664 results on '"Dvorák J"'
Search Results
202. Results of simulation of non-homogeneous ventilatory mechanics for a patient-computer arrangement
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Cettl, L., Dvorak, J., Felkel, H., and Feuereisl, R.
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- 1979
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203. Sensitivity analysis of biological models
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Cettl, L. and Dvořák, J.
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- 1982
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204. Women's place in space exploration
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Sýkora, J., Šolcová, I., Dvořák, J., Polánková, M., and Tomeček, A.
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- 1996
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205. Behavioural and EEG changes induced by the pyrethroid insecticide cyhalothrin
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Z̆ufan, L., Kubát, J., Formánek, J., Fuchs, A., Tobis̆ková, G., Zajic̆ek, P., Vodic̆ková, J., R̆hák, P., and Dvor̆ak, J.
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- 1989
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206. 17 Fibrinolytic capacity in young survivors of myocardial infarction and its affection by low-energy diet
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Čepelák, V., Dvořák, J., and Beránek, V.
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- 1988
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207. Motor evoked potentials (MEP) in cervical spondylotic myelopathy
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Tanaka, M., Yonenobu, K., Ono, K., and Dvorak, J.
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- 1997
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208. In memoriam Milan Morávek 1923–1980
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Dvořák, J.
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- 1980
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209. Principles of electrochemistry : Wiley, New York, 1987 (ISBN 0-471-91211-5). xi+447 pp. Price £49.50
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Koryta, J., Dvorak, J., and Bond, Alan M.
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- 1987
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210. The Isolation of Trichophyton Gallinae (Mégnin) Silva Et Benham 1952 from Man
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Dvořák, J. and Otčenášek, M.
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- 1964
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211. Uncovering the dispersion history, adaptive evolution and selection of wheat in China.
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Zhou Y, Chen Z, Cheng M, Chen J, Zhu T, Wang R, Liu Y, Qi P, Chen G, Jiang Q, Wei Y, Luo MC, Nevo E, Allaby RG, Liu D, Wang J, Dvorák J, and Zheng Y
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- China, Gene Frequency genetics, Genetic Variation genetics, Genome, Plant genetics, Triticum physiology, Triticum genetics
- Abstract
Wheat was introduced to China approximately 4500 years ago, where it adapted over a span of time to various environments in agro-ecological growing zones. We investigated 717 Chinese and 14 Iranian/Turkish geographically diverse, locally adapted wheat landraces with 27 933 DArTseq (for 717 landraces) and 312 831 Wheat660K (for a subset of 285 landraces) markers. This study highlights the adaptive evolutionary history of wheat cultivation in China. Environmental stresses and independent selection efforts have resulted in considerable genome-wide divergence at the population level in Chinese wheat landraces. In total, 148 regions of the wheat genome show signs of selection in at least one geographic area. Our data show adaptive events across geographic areas, from the xeric northwest to the mesic south, along and among homoeologous chromosomes, with fewer variations in the D genome than in the A and B genomes. Multiple variations in interdependent functional genes such as regulatory and metabolic genes controlling germination and flowering time were characterized, showing clear allelic frequency changes corresponding to the dispersion of wheat in China. Population structure and selection data reveal that Chinese wheat spread from the northwestern Caspian Sea region to South China, adapting during its agricultural trajectory to increasingly mesic and warm climatic areas., (© 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.)
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- 2018
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212. Osteoarthritis in Football.
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Salzmann GM, Preiss S, Zenobi-Wong M, Harder LP, Maier D, and Dvorák J
- Abstract
Football is currently the most popular sporting activity in the world. Multiple reports have shown that a high incidence of osteoarthritis is found in football players. Evidence clearly shows that traumatic injury significantly predisposes players for such pathophysiology. Injuries are frequent in amateur as well as professional football players, with knee and ankle accounting for the most severe injuries. Many professional athletes lose playing time due to injuries and many are forced into early retirement. Posttraumatic osteoarthritis is a common finding among ex-football players with numbers well above the normal population. Today's surgical techniques are advanced and capable of restoring the joint to a certain extent. However, a restitution ad integrum is reached only in very rare cases. Professional football players that return to play after serious injuries perform their extremely strenuous activity on morphologically compromised joints. Incomplete rehabilitation and pressure to return to play after an injurious event clearly put the athlete at an even higher risk for joint degeneration. Prevention strategies, improved surgical management, strict rehabilitation, as well as future aspects such as early suppression of inflammation, personalized medicine, and predictive genomics DNA profiling are needed to reduce incidence and improve the health perspectives of football players.
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- 2017
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213. Injuries of veteran football (soccer) players in Germany.
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Hammes D, Aus Der Fünten K, Kaiser S, Frisen E, Dvorák J, and Meyer T
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- Adult, Age Factors, Aged, Athletic Injuries etiology, Germany epidemiology, Humans, Incidence, Male, Middle Aged, Physical Conditioning, Human adverse effects, Prospective Studies, Athletic Injuries epidemiology, Lower Extremity injuries, Muscle, Skeletal injuries, Soccer injuries
- Abstract
There is a lack of injury data for the population of veteran football players. Therefore, a prospective study was conducted to investigate injury incidences and characteristics. Over one season, injuries and exposure of 18 teams (n = 265 players, age: 44.2±7.3 years, BMI: 26.6±3.2 kg/m(2)) were documented. Sixty-three players sustained a total of 88 injuries during the season. The incidence of training injuries (4.5 per 1000 hours) was significantly lower than of match injuries (24.7 per 1000 hours). The majority of injuries (n = 73; 83%) were located at the lower extremities, 52 (47%) were muscle injuries. The injury incidence of veteran football players is similar to other male football players of different skill levels and age groups, indicating a need for the implementation of preventive measures. Prevention programmes should consider the specific injury characteristics, with more muscle injuries in this population compared with younger football players.
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- 2015
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214. Zero tolerance: the future of head injury in sports.
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Aubry M, Dvorák J, McCrory P, Meeuwisse W, Raftery M, Sills A, and Engebretsen L
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- Female, Humans, Male, Athletic Injuries therapy, Brain Concussion therapy
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- 2013
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215. Evidence-based approach to revising the SCAT2: introducing the SCAT3.
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Guskiewicz KM, Register-Mihalik J, McCrory P, McCrea M, Johnston K, Makdissi M, Dvorák J, Davis G, and Meeuwisse W
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- Ataxia diagnosis, Evidence-Based Medicine, Humans, Physical Examination methods, Post-Concussion Syndrome diagnosis, Postural Balance, Surveys and Questionnaires standards, Athletic Injuries diagnosis, Brain Concussion diagnosis, Trauma Severity Indices
- Abstract
The Sport Concussion Assessment Tool 2 (SCAT2), which evolved from the 2008 Concussion in Sport Group (CISG) Consensus meeting, has been widely used internationally for the past 4 years. Although the instrument is considered very practical and moderately effective for use by clinicians who manage concussion, the utility and sensitivity of a 100-point scoring system for the SCAT2 has been questioned. The 2012 CISG Consensus Meeting provided an opportunity for several of the world's leading concussion researchers and clinicians to present data and to share experiences using the SCAT2. The purpose of this report is to consider recommendations by the CISG, and to review the current literature to identify the most sensitive and reliable concussion assessment components for inclusion in a revised version-the SCAT3. Through this process, it was determined that important clinical information can be ascertained in a streamlined manner through the use of a multimodal instrument such as the SCAT3. This test battery should include an initial assessment of injury severity using the Glasgow Coma Scale, immediately followed by observing and documenting concussion signs. Once this is complete, symptom endorsement and symptom severity, neurocognitive function and balance function should be assessed in any athlete suspected of sustaining a concussion. There is no evidence to support the use of a composite/total score; however, there is good evidence to support the use of each component (scored independently) in a revised assessment tool.
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- 2013
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216. What are the most effective risk-reduction strategies in sport concussion?
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Benson BW, McIntosh AS, Maddocks D, Herring SA, Raftery M, and Dvorák J
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- Biomechanical Phenomena, Equipment Design, Head Protective Devices, Humans, Mouth Protectors, Muscle Strength physiology, Muscle, Skeletal physiology, Neck physiology, Risk Reduction Behavior, Sports legislation & jurisprudence, Athletic Injuries prevention & control, Brain Concussion prevention & control
- Abstract
Aim: To critically review the evidence to determine the efficacy and effectiveness of protective equipment, rule changes, neck strength and legislation in reducing sport concussion risk., Methods: Electronic databases, grey literature and bibliographies were used to search the evidence using Medical Subject Headings and text words. Inclusion/exclusion criteria were used to select articles for the clinical equipment studies. The quality of evidence was assessed using epidemiological criteria regarding internal/external validity (eg, strength of design, sample size/power, bias and confounding)., Results: No new valid, conclusive evidence was provided to suggest the use of headgear in rugby, or mouth guards in American football, significantly reduced players' risk of concussion. No evidence was provided to suggest an association between neck strength increases and concussion risk reduction. There was evidence in ice hockey to suggest fair-play rules and eliminating body checking among 11-years-olds to 12-years-olds were effective injury prevention strategies. Evidence is lacking on the effects of legislation on concussion prevention. Equipment self-selection bias was a common limitation, as was the lack of measurement and control for potential confounding variables. Lastly, helmets need to be able to protect from impacts resulting in a head change in velocities of up to 10 and 7 m/s in professional American and Australian football, respectively, as well as reduce head resultant linear and angular acceleration to below 50 g and 1500 rad/s(2), respectively, to optimise their effectiveness., Conclusions: A multifactorial approach is needed for concussion prevention. Future well-designed and sport-specific prospective analytical studies of sufficient power are warranted.
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- 2013
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217. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012.
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McCrory P, Meeuwisse WH, Aubry M, Cantu B, Dvorák J, Echemendia RJ, Engebretsen L, Johnston K, Kutcher JS, Raftery M, Sills A, Benson BW, Davis GA, Ellenbogen RG, Guskiewicz K, Herring SA, Iverson GL, Jordan BD, Kissick J, McCrea M, McIntosh AS, Maddocks D, Makdissi M, Purcell L, Putukian M, Schneider K, Tator CH, and Turner M
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- Acute Disease, Adolescent, Aggression, Athletic Injuries diagnosis, Athletic Injuries prevention & control, Brain Concussion diagnosis, Brain Concussion prevention & control, Child, Clinical Competence standards, Clinical Protocols, Cognition Disorders diagnosis, Cognition Disorders etiology, Depressive Disorder etiology, Diagnosis, Computer-Assisted, Diagnostic Imaging methods, Emergency Treatment methods, Female, Head Protective Devices, Health Policy, Humans, Injury Severity Score, Male, Neurologic Examination methods, Neuropsychological Tests, Recovery of Function, Rest, Risk Assessment, Sex Factors, Sports Medicine standards, Switzerland, Unconsciousness complications, Violence, Athletic Injuries therapy, Brain Concussion therapy
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- 2013
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218. What is the lowest threshold to make a diagnosis of concussion?
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McCrory P, Meeuwisse WH, Echemendia RJ, Iverson GL, Dvorák J, and Kutcher JS
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- Acute Disease, Athletic Injuries etiology, Brain Concussion etiology, Brain Diseases, Metabolic diagnosis, Brain Diseases, Metabolic etiology, Consensus, Diagnosis, Differential, Glasgow Coma Scale, Humans, Memory Disorders diagnosis, Memory Disorders etiology, Nervous System Diseases diagnosis, Nervous System Diseases etiology, Self Report, Terminology as Topic, Athletic Injuries diagnosis, Brain Concussion diagnosis
- Abstract
Objective: The purpose of this review is to examine the evidence for determining the lowest threshold for diagnosing a sport-related concussion., Data Sources: MEDLINE, CINAHL, EMBASE, Mosby's Index, PsycEXTRA, PsycINFO and Scopus. Key words included sports concussion, concussion assessment, diagnosis, concussion symptoms, onfield assessment and sports-related traumatic brain injury., Results: The majority of concussions in sport occur without loss of consciousness or frank neurological signs. Some of the hallmark signs of acute concussion include mental confusion, memory and balance disturbance. Over the course of the first 24 h, the most common symptoms include headache, nausea, dizziness and balance problems, blurred vision or other visual disturbance, confusion, memory loss and 'fatigue'. Symptoms such as tiredness, irritability, nervousness or anxiety, sleep disturbance and sensitivity to light or noise may be noticed in the days after injury. The pathophysiology of sports concussion remains poorly understood. There appears to be a period of vulnerability following concussion in which an overlapping injury might cause magnified pathophysiology., Conclusions: Sport-related concussions can be difficult to diagnose. Concussion produces an evolving constellation of somatic, cognitive and neurobehavioral symptoms that are typically most severe during the earliest acute postinjury period (ie, within the first 24-48 h) and diminish over a matter of several days to weeks in the majority of athletes. Athletes suspected of concussion should be removed from play and evaluated thoroughly.
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- 2013
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219. Hepatic arterial infusion for biliary tract carcinoma: single-center experience.
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Melichar B, Voboril Z, Dvorák J, Ferko A, Rozkos T, and Krajina A
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- Adult, Aged, Aged, 80 and over, Biliary Tract Neoplasms mortality, Female, Hepatic Artery, Humans, Male, Middle Aged, Retrospective Studies, Antineoplastic Combined Chemotherapy Protocols administration & dosage, Biliary Tract Neoplasms drug therapy, Infusions, Intra-Arterial
- Abstract
Aim: The aim of the present study was to evaluate a single-center experience in hepatic arterial infusion (HAI) of patients with biliary tract carcinomas., Patients and Methods: A retrospective analysis of 60 patients treated between 1997 and 2011 was performed., Results: Most patients were treated with HAI of a combination of 5-fluorouracil, folinic acid and cisplatin. The response was not evaluable in most patients, predominantly because of prior surgical procedures. The median survival of all patients was 15.1 months (5-year survival=13%). The survival was significantly better in patients treated with radical surgery (median=50.1 months, 5-year survival=45%) or palliative surgery (median=22.5 months, 5-year survival=13%) compared to no surgery (median=7.6 months, 5-year survival=3%)., Conclusion: The current data demonstrate the efficacy of HAI in patients with biliary tract carcinoma. HAI is a therapeutic method to be considered in patients with inoperable biliary tract carcinoma and no extrahepatic spread.
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- 2013
220. Hepatic arterial infusion of irinotecan, 5-Fluorouracil and leucovorin in patients with liver metastases from colorectal carcinoma.
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Melichar B, Voboril Z, Krajina A, Malírová E, Weiner P, Nová M, Ryska A, and Dvorák J
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- Adult, Aged, Camptothecin administration & dosage, Camptothecin analogs & derivatives, Disease-Free Survival, Female, Fluorouracil administration & dosage, Hepatic Artery, Humans, Infusions, Intra-Arterial, Irinotecan, Leucovorin administration & dosage, Male, Middle Aged, Retrospective Studies, Survival Rate, Antineoplastic Combined Chemotherapy Protocols administration & dosage, Colorectal Neoplasms drug therapy, Colorectal Neoplasms pathology, Liver Neoplasms drug therapy, Liver Neoplasms secondary
- Abstract
Aim: The aim of the present study was to evaluate single center experience with hepatic arterial infusion (HAI) of irinotecan, 5-fluorouracil and leucovorin in patients with liver metastases from colorectal carcinoma (CRC)., Patients and Methods: A retrospective analysis of 68 patients treated between 1998 and 2007 was performed., Results: Among 60 patients who had no simultaneous liver-directed procedure (LDP), the best results obtained were complete response in two patients (3%), partial response in 18 patients (30%), and stable disease in 23 patients (38%), for an overall disease control rate of 72%. Median progression-free survival was 11 months, and median survival was 24 months. Overall survival was significantly better in patients with simultaneous LDP or secondary resection. Steatosis was present in all secondary resection specimens., Conclusion: Our data demonstrate the efficacy of HAI of irinotecan combined with 5-fluorouracil and leucovorin for liver metastases from CRC, specifically in patients also treated with LDP.
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- 2012
221. Hepatic arterial infusion of oxaliplatin, 5-fluorouracil and leucovorin in patients with liver metastases from colorectal carcinoma.
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Melichar B, Ferko A, Krajina A, Rousková L, Dvorák J, Svébisova H, Neoral C, Köcher M, Malirová E, and Paral J
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- Adult, Aged, Aged, 80 and over, Carcinoembryonic Antigen blood, Female, Fluorouracil administration & dosage, Hepatic Artery, Humans, Leucovorin administration & dosage, Male, Middle Aged, Organoplatinum Compounds administration & dosage, Oxaliplatin, Retrospective Studies, Antineoplastic Combined Chemotherapy Protocols administration & dosage, Colorectal Neoplasms pathology, Infusions, Intra-Arterial, Liver Neoplasms drug therapy
- Abstract
Purpose: Limited data are available regarding the efficacy of hepatic arterial infusion (HAI) of oxaliplatin in patients with liver metastases from colorectal carcinoma (CRC). The aim of the present study was to evaluate the results of HAI of oxaliplatin combined with 5-fluorouracil (5-FU) and leucovorin (LV) in patients with such metastases., Methods: A retrospective analysis of 22 CRC patients treated with HAI of combination of oxaliplatin and 5-FU and LV was performed., Results: Partial response (PR) was observed in 4 (18%) patients and stable disease (SD) in 7, with an overall disease control rate of 50%. The median progression-free (PFS) and overall survival (OS) were 7 and 11 months, respectively. Two patients treated with first-line treatment underwent subsequent liver resection. In 2 patients, HAI of oxaliplatin, 5-FU and LV was combined with systemic administration of bevacizumab., Conclusion: Our data demonstrate reasonable efficacy of HAI with oxaliplatin, 5-FU and LV in patients with liver metastases from CRC.
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- 2012
222. [Acute retinal necrosis].
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Mach R, Brichová M, Pokorná J, Dvorák J, and Gregusová D
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- Adult, Female, Humans, Male, Middle Aged, Retinal Necrosis Syndrome, Acute drug therapy, Retinal Necrosis Syndrome, Acute diagnosis
- Abstract
Aim: The paper documents the cumulating appearance of 3 cases of the acute retinal necrosis (ARN) during one-year period at the district (local) eye department. It concerns the etiology, the treatment, evaluates its results and reveals the recommendations for the clinical practice., Methods: retrospective study., Results: The ARN was diagnosed in 3 patients (2 woman and 1 man) at the age of 29, 43, and 58 years. Uveitis was unilateral in all cases. All three patients were treated early with adequate systemic antiviral (acyclovir) and corticosteroids treatment, which caused improving of the clinical findings and visual acuity as well. In 2 patients, pars plana vitrectomy was performed. Despite the long-lasting chronic combined medication, during the follow-up period in these 2 patients the decrease of the visual acuity occurred., Conclusion: ARN is very rare, vision-threatening viral disease. The appearance of 3 cases of ARN at a local hospital is unusual. The diagnosis may be established according to the characteristic clinical findings and to its development. To determine the pathogen (varicella zoster virus in 70 %, herpes simplex virus in almost 30 %, and cytomegalovirus very rarely) is not critical for the diagnosis establishment. The early use of specific virostatic drugs is the key assumption for optimal ARN treatment, as it happened in our patients. Contrary to the adequate treatment, retinal complications may occur, and often, even after successful pars plana vitrectomy, the decrease of visual functions is possible. For the ophthalmologic practice, it is important to remember, that in case of ARN suspicion, it is urgent to start the virostatic treatment and to add corticosteroids not earlier than after 24-48 hours. In case of complications, it is necessary to contact the specialized vitreoretinal center immediately. It is necessary to inform the patient about very serious condition of the infected eye and its uncertain prognosis contrary to the adequate treatment, and about the danger to the opposite eye in case of delay of missing treatment. In case of herpetic anterior uveitis, the fundus examination, including the periphery of the retina is important.
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- 2012
223. Special Issue on Articular Cartilage Injury in the Football (Soccer) Player.
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Mithoefer K, Peterson L, Saris D, Mandelbaum B, and Dvorák J
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- 2012
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224. Cartilage Issues in Football (Soccer): An Executive Summary of the Fédération Internationale de Football Association (FIFA)/ International Cartilage Repair Society (ICRS) Initiative.
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Mandelbaum B, Mithoefer K, Peterson L, Saris D, and Dvorák J
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- 2012
- Full Text
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225. Critical evaluation of the optimal medical therapy in the cardiac resynchronization therapy candidates--single centre experience.
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Vondráková D, Málek F, Dvorák J, Sedivá L, Kupec J, Petrů J, Táborský M, and Neuzil P
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- Adrenergic beta-Antagonists administration & dosage, Aged, Angiotensin Receptor Antagonists administration & dosage, Angiotensin-Converting Enzyme Inhibitors administration & dosage, Anti-Arrhythmia Agents administration & dosage, Carbazoles administration & dosage, Cardiac Resynchronization Therapy, Carvedilol, Enalapril administration & dosage, Female, Heart Failure therapy, Humans, Losartan administration & dosage, Male, Propanolamines administration & dosage, Defibrillators, Implantable, Heart Failure drug therapy
- Abstract
Unlabelled: The aim of the present study was to evaluate the optimal medical therapy in the chronic heart failure (CHF) patients referred from the comunity centres and the outpatients cardiology clinics for the cardiac resynchronization therapy with defibrilator (CRTD) to the Department of Cardiology, Na Homolce Hospital with the device implantation between 1st January 2008 and 30st September 2009., Methods: The optimal medical therapy was analysed retrospectively from the medical records of 179 consecutive CHF patients NYHA class III-IV. Beta-blockers (BB) were used only in 81% subjects referred for CRTD, ACE inhibitors (ACEI) were used only in 68% patients Angiotensin receptor blockers (ARB) were used in 18% subjects. ACEI or ARB were used in 81%, spironolacton was use in 59%. Recommended target DD for BB (carvedilol 25 mg bid) was used only in 13% subjects, recommended target DD for ACEI (enalapril 10 mg bid) was used only in 9.4% patients., Results: In the Department of Cardiology, the optimal medical therapy was changed after CRTD, BB were used in 95% subjects at discharge (p < 0.01) and the number of patients reaching at least of 50% of recommended daily dose (DD) of BB increased (p < 0.05). ACEI were recommended after CRTD in 80% subjects after implantation (p < 0.05), the number of patients reaching at least of 50% of recommended DD for ACEIs increased too (p < 0.05). There was no significant difference in ARB use recomended in the hospital (19% after CRTD - NS). ACEI or ARB were used in 98% patients after the device implanted (p < 0.05) and spironolacton in 77% after CRTD (p < 0.05)., Conclusions: Despite optimal composition of the optimal medical heart failure therapy only small number of CRTD candidates are reaching recommended drug dose. The optimization of the medical therapy in the specialized center lead to significantly higher proportion of CHF using the optimal therapy with the increased dose of BB and ACEI.
- Published
- 2011
226. [Eye and inflammatory bowel diseases].
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Brichová M, Heissigerová J, Svozílková P, Dvorák J, Jenícková D, and Ríhová E
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- Adult, Aged, Female, Humans, Male, Middle Aged, Uveitis drug therapy, Inflammatory Bowel Diseases complications, Uveitis complications
- Abstract
Aim: To point out the wide range of ocular features of inflammatory bowel diseases (IBD), focusing on uveitis., Methods: A retrospective study., Results: In the Centre for diagnosis and therapy of uveitis of our Ophthalmology Department, we have in years 2003-2010 followed in total 18 patients with intraocular inflammation associated with IBD: anterior uveitis (14), vasculitis (1), panuveitis (1), infectious uveitis as a secondary complication of systemic immunosuppressive therapy (2). The most often diagnosis was mild to moderate recurrent acute anterior uveitis. We have noticed more severe course of uveitis in patients with the HLA B27 positivity. Part of this paper consists of an overview of other ocular manifestations of IBD and current available therapeutical strategies., Conclusion: Ocular manifestations of IBD can be a valuable signal of the activity of the primary disease. The knowledge of the ocular manifestations of these systemic diseases and of possible complications is required for successful interdisciplinary care of patients with IBD. While local treatment is fully in hands of an ophthalmologist, the form and extent of the systemic treatment is necessary to coordinate with gastroenterologists.
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- 2011
227. Gastroduodenal, intestinal and colonic permeability during anticancer therapy.
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Melichar B, Hyspler R, Kalábová H, Dvorák J, Tichá A, and Zadák Z
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- Adult, Aged, Colon metabolism, Duodenum metabolism, Humans, Middle Aged, Permeability, Sucrose analogs & derivatives, Sucrose pharmacokinetics, Antineoplastic Agents pharmacokinetics, Gastric Mucosa metabolism, Intestinal Mucosa metabolism
- Abstract
Background/aims: Measurement of the permeability of gut mucosa may offer a method for objective assessment of mucosal dysfunction during cancer therapy., Methodology: Gastroduodenal, intestinal and colonic permeability was studied by using capillary gas chromatography and measuring urinary sucralose, sucrose, lactulose, xylose and mannitol levels. A total of 41 patients with metastatic colorectal carcinoma or epithelial ovarian carcinoma were studied before and during chemotherapy with the combinations of cetuximab, irinotecan, 5-fluorouracil and leucovorin; bevacizumab, oxaliplatin, 5-fluorouracil and leucovorin; or paclitaxel/ platinum., Results: Compared to pretreatment values, a significant increase was observed during the first cycle of therapy in the percentage of sucrose, sucrose/mannitol ratio, lactulose and lactulose/ mannitol ratio in patients treated with the combination of bevacizumab, oxaliplatin, 5-fluorouracil and leucovorin. No changes were observed in patients treated with cetuximab, irinotecan, 5-fluorouracil and leucovorin, but these patients had significantly higher baseline percentage of lactulose excretion and sucrose/mannitol and lactulose/ mannitol ratios., Conclusions: An increase in gastroduodenal and intestinal permeability was observed in patients treated with bevacizumab, oxaliplatin, 5-fluorouracil and leucovorin, but not in patients treated with cetuximab, irinotecan, 5-fluorouracil and leucovorin. No significant increase in colonic permeability was observed, but the present method was insufficient to detect colonic permeability in a significant proportion of patients.
- Published
- 2011
- Full Text
- View/download PDF
228. [Intrathoracic goiter--undiagnosed nevertheless operated].
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Dvorák J
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- Humans, Goiter, Substernal diagnosis, Goiter, Substernal surgery
- Published
- 2011
229. Intensity-modulated radiotherapy in the treatment of subhepatic carcinomas.
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Petera J, Kasaová L, Paluska P, Sirák I, Jansa J, Macingová Z, Dvorák J, and Soumarova R
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- Aged, Female, Humans, Male, Middle Aged, Radiotherapy Dosage, Bile Duct Neoplasms radiotherapy, Bile Ducts, Intrahepatic, Cholangiocarcinoma radiotherapy, Gallbladder Neoplasms radiotherapy, Radiotherapy, Intensity-Modulated methods
- Abstract
Background/aims: The aim of our study was to evaluate preliminary results of intensity modulated radiotherapy (IMRT) in patients with inoperable subhepatic tumors., Methodology: Thirteen patients with inoperable cholangiocarcinoma or gall bladder carcinoma were treated by biliary drainage and intensity modulated radiotherapy. In patients with tumors limited to the biliary duct only tumor stenosis was irradiated to the dose of 50-60 Gy. In patients with bulky extraductal tumors the dose was 50 Gy/25 fractions to the whole tumor and an integrated boost was used to raise the dose to the malignant stenosis to 60 Gy/25 fractions., Results: Doses to organs at risk (duodenum, small intestine, liver) were in tolerable limits. In four patients transient fever occurred; one patient had duodenal bleeding that resolved after conservative treatment. Recurrent dilatation of the biliary tract was observed in 4 patients and was managed by exchange of the internal biliary drainage. Median survival was 10.4 months, 5 patients survived for more than one year following diagnosis., Conclusions: IMRT of inoperable extrahepatic biliary tract tumors allows application of high doses of radiation to the tumor with effective sparing of healthy tissues. The control of jaundice is good. In selected cases IMRT may prolong overall survival.
- Published
- 2011
230. Intestinal permeability, vitamin A absorption, alpha-tocopherol, and neopterin in patients with rectal carcinoma treated with chemoradiation.
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Dvorák J, Melichar B, Hyspler R, Krcmová L, Urbánek L, Kalábová H, Kasparová M, and Solichová D
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- Adenocarcinoma drug therapy, Adenocarcinoma immunology, Adenocarcinoma radiotherapy, Aged, Antimetabolites, Antineoplastic therapeutic use, Antioxidants metabolism, Carbohydrates urine, Chromatography, Gas, Chromatography, High Pressure Liquid, Combined Modality Therapy, Dietary Carbohydrates pharmacokinetics, Diterpenes, Female, Fluorouracil therapeutic use, Humans, Male, Middle Aged, Rectal Neoplasms drug therapy, Rectal Neoplasms immunology, Rectal Neoplasms radiotherapy, Retinyl Esters, Vitamin A administration & dosage, Vitamin A analogs & derivatives, Vitamin A blood, Adenocarcinoma metabolism, Antimetabolites, Antineoplastic adverse effects, Fluorouracil adverse effects, Intestinal Absorption drug effects, Intestinal Absorption radiation effects, Neopterin urine, Radiotherapy, High-Energy adverse effects, Rectal Neoplasms metabolism, Vitamin A pharmacokinetics, alpha-Tocopherol blood
- Abstract
Although gastrointestinal toxicity is one of the most common side effects of anticancer therapy, the diagnosis and assessment of this toxicity still depend mostly on anamnestic data. Measurement of intestinal permeability is one of potential methods of non-invasive laboratory evaluation of gastrointestinal toxicity. The aim of the present study was to investigate intestinal permeability, vitamin A absorption, serum alpha-tocopherol, and urinary neopterin in patients with rectal carcinoma treated with chemoradiation. We have studied intestinal permeability, vitamin A absorption, serum alpha-tocopherol, and urinary neopterin in 17 patients with rectal carcinoma treated with chemoradiation. Urinary lactulose, mannitol, and xylose were measured by capillary gas chromatography, and serum alpha-tocopherol, retinol, retinyl esters, and urinary neopterin were determined by high-performance liquid chromatography. Lactulose/mannitol ratio was increased 5 and 6 weeks after the start of the treatment. Serum alpha-tocopherol was decreased significantly throughout the course of treatment, but no significant changes were observed in postprandial serum concentrations of retinyl esters or in the concentrations of urinary neopterin. A correlation was observed between baseline parameters of intestinal permeability and urinary neopterin. The measurement of intestinal permeability using the lactulose/mannitol test may represent a sensitive tool in the detection of changes associated with chemoradiation in patients with rectal carcinoma. The therapy is also associated with a decrease of alpha-tocopherol.
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- 2010
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231. [Proximal humeral fracture complicated by axillary artery lesion--a case review].
- Author
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Edelmann K, Dvorák J, Kopp L, and Obruba P
- Subjects
- Accidents, Traffic, Aged, Axillary Artery surgery, Blood Vessel Prosthesis Implantation, Female, Fracture Fixation, Internal, Humans, Shoulder Fractures surgery, Axillary Artery injuries, Shoulder Fractures complications
- Abstract
Although proximal humeral fractures are common diagnosis in emergency, cases of axillary artery injuries are rare. Authors present a patient, who underwent high energy trauma during a traffic accident like a pedestrian. Comminuted proximal humeral fracture was complicated with an occlusion of the third part of the axillary artery. There was necessary an urgent surgery, ostesynthesis with locking plate and reconstruction of the axillary artery by interposition of expanded polytetrafluoroethylene (ePTFE) graft. Postoperative course was uncomplicated, patient had no symptoms of ischaemia of extremity or claudication and started physiotherapy. In review of the literature authors present possible reasons of arterial injuries, possibilities of treatments to minimize risk of amputation. Axillary artery injury from proximal humeral fracture is rare, but every surgeon must be aware of this entity in order to avoid fatal complications.
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- 2010
232. Intestinal permeability, vitamin A absorption and serum alpha-tocopherol during therapy with gefitinib.
- Author
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Melichar B, Dvorák J, Kalábová H, Hyspler R, Krcmová L, Kasparová M, Urbánek L, and Solichová D
- Subjects
- Adult, Aged, Case-Control Studies, Female, Gefitinib, Humans, Male, Middle Aged, Permeability drug effects, Intestinal Absorption drug effects, Intestines drug effects, Quinazolines pharmacology, Quinazolines therapeutic use, Vitamin A metabolism, alpha-Tocopherol blood
- Abstract
Measurement of intestinal permeability represents one of the potential methods of noninvasive laboratory assessment of gastrointestinal toxicity of anticancer therapy. We have assessed intestinal permeability (by measuring absorption of lactulose, mannitol, and xylose), vitamin A absorption and serum alpha-tocopherol in patients with non-small cell lung carcinoma or head and neck carcinomas treated with gefitinib. Lactulose, mannitol and xylose were determined by capillary gas chromatography, and retinol, alpha-tocopherol, retinyl stearate and retinyl palmitate were determined by high-performance liquid chromatography. Compared to healthy controls, patients had significantly increased lactulose/mannitol ratio and lower postprandial retinyl palmitate and retinyl stearate concentrations. Compared with pre-treatment values, xylose absorption was decreased and lactulose/mannitol and lactulose/xylose ratios were increased during the therapy. A significant decrease of serum alpha-tocopherol was evident throughout the course of therapy. In contrast, only minor alterations of vitamin A absorption were observed. In conclusion, an alteration in intestinal permeability reflected in increased lactulose/mannitol and lactulose/xylose ratios was observed during gefitinib therapy. Potential association between decreased serum alpha-tocopherol concentrations and the toxicity of gefitinib therapy should be further investigated.
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- 2010
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233. Biolistic transformation of Schistosoma mansoni: Studies with modified reporter-gene constructs containing regulatory regions of protease genes.
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Dvorák J, Beckmann S, Lim KC, Engel JC, Grevelding CG, McKerrow JH, and Caffrey CR
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- Animals, Biolistics, Cathepsin D genetics, Cathepsin D metabolism, Cathepsin F genetics, Cathepsin F metabolism, Gene Expression Regulation, Helminth Proteins metabolism, Peptide Hydrolases metabolism, Schistosoma mansoni metabolism, Genes, Reporter, Helminth Proteins genetics, Peptide Hydrolases genetics, Regulatory Sequences, Nucleic Acid, Schistosoma mansoni genetics, Transformation, Genetic
- Abstract
Biolistics of the flatworm parasite Schistosoma mansoni facilitates the accurate spatial expression of transgenes under the control of gene-specific promoter elements. To improve transgene expression, either in the number of positive worms and/or an increased transgene signal per worm, we tested plasmid constructs incorporating 5' and 3' gene-specific genomic fragments, and parts of the open reading frame for two S. mansoni proteases, cathepsins F and D (SmCF and SmCD). GFP-expression was gut-localized, a novel finding for SmCD and consistent with previous data for SmCF. The mCherry fluorescent protein can also operate as a reporter. Though certain constructs imparted stronger and better distributed signals per positive worm, the low yields throughout (1-5% positive per experiment) precluded further quantifications of improvement. Electroporation of the same constructs was also weakly efficient (1-10% positives per experiment). However, reporter signals were found in tissues other than the gut, which may represent dysregulated transcription.
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- 2010
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234. Intestinal permeability, vitamin A absorption and serum alpha-tocopherol in gastrointestinal stromal tumor patients treated with imatinib.
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Melichar B, Kašparová M, Kalábová H, Dvorák J, Hyšpler R, Tichá A, Krcmová L, Plíšek J, Holecková P, and Solichová D
- Subjects
- Adult, Aged, Aged, 80 and over, Antineoplastic Agents therapeutic use, Benzamides, Female, Gastrointestinal Stromal Tumors blood, Gastrointestinal Stromal Tumors drug therapy, Humans, Imatinib Mesylate, Intestinal Mucosa drug effects, Intestinal Mucosa metabolism, Male, Middle Aged, Permeability, Piperazines therapeutic use, Pyrimidines therapeutic use, Antineoplastic Agents pharmacology, Dietary Sucrose pharmacokinetics, Gastrointestinal Stromal Tumors metabolism, Intestinal Absorption drug effects, Piperazines pharmacology, Pyrimidines pharmacology, Vitamin A pharmacokinetics, alpha-Tocopherol blood
- Abstract
Administration of imatinib is the therapy of choice in patients with advanced (inoperable) or metastatic gastrointestinal stromal tumors (GIST). Gastrointestinal toxicity is one of the most common side effects of anticancer therapy, including imatinib. Measurement of intestinal permeability represents a method of noninvasive laboratory assessment of gastrointestinal toxicity. We have measured intestinal permeability (by determining absorption of lactulose, mannitol and xylose), vitamin A absorption and serum alpha-tocopherol in 16 patients with advanced/metastatic GIST treated with imatinib. Lactulose/mannitol and lactulose/xylose ratios as well as parameters of vitamin A absorption did not change significantly during the treatment, but a significant decrease of alpha-tocopherol was observed. We conclude that, in contrast to most other anticancer agents studied so far, imatinib does not have an effect on intestinal permeability. No effect on vitamin A absorption was observed, but serum alpha-tocopherol decreased significantly during the treatment.
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- 2010
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235. Analysis of free fatty acids in beer: comparison of solid-phase extraction, solid-phase microextraction, and stir bar sorptive extraction.
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Horák T, Culík J, Cejka P, Jurková M, Kellner V, Dvorák J, and Hasková D
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- Chromatography, Gas, Solid Phase Extraction instrumentation, Solid Phase Microextraction instrumentation, Solid Phase Microextraction methods, Beer analysis, Fatty Acids analysis, Solid Phase Extraction methods
- Abstract
Solid-phase extraction (SPE), solid-phase microextraction (SPME) using carbowax/divinylbenzen fiber, and stir bar sorptive extraction (SBSE) followed by solvent back extraction have been used for the extraction of free fatty acids (caproic, caprylic, pelargonic, capric, lauric, myristic, palmitic, stearic, oleic, linoleic, and linolenic acids) from beer. Subsequent gas chromatographic analyses with flame ionization detection were used for the determination of these compounds. Medium-chain fatty acids (caproic-lauric acid) were determined as free acids, and long-chain fatty acids (myristic-linolenic acids) were determined as methyl esters after methylation by BF(3)-methanol 14%. Linearity, recovery, and repeatability of all methods have been determined and compared with the SPE method used as a reference (SPME method was used only for medium-chain fatty acid determination). All three procedures provide similar working parameters characterized by high repeatability (2.3-16.3%) and good linearity (correlation coefficient ranging from 0.9919 to 0.9999). Results of beer analyses obtained by using these three methods were highly correlated. Although all methods provide compatible alternatives, for medium-chain fatty acid analysis SPME may be a more appropriate technique due to its operational simplicity, repeatability, and low cost.
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- 2009
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236. Aza-peptidyl Michael acceptor and epoxide inhibitors--potent and selective inhibitors of Schistosoma mansoni and Ixodes ricinus legumains (asparaginyl endopeptidases).
- Author
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Ovat A, Muindi F, Fagan C, Brouner M, Hansell E, Dvorák J, Sojka D, Kopácek P, McKerrow JH, Caffrey CR, and Powers JC
- Subjects
- Amino Acid Sequence, Animals, Biological Availability, Drug Design, Enzyme Inhibitors chemical synthesis, Enzyme Inhibitors chemistry, Enzyme Inhibitors pharmacokinetics, Enzyme Inhibitors pharmacology, Kinetics, Oligopeptides chemical synthesis, Oligopeptides pharmacokinetics, Aza Compounds chemistry, Cysteine Endopeptidases metabolism, Epoxy Compounds chemistry, Ixodes enzymology, Oligopeptides chemistry, Oligopeptides pharmacology, Schistosoma mansoni enzymology
- Abstract
Aza-peptide Michael acceptors and epoxides with the general structure of YCO-Ala-Ala-AAsn-trans-CH horizontal lineCHCOR and YCO-Ala-Ala-AAsn-EP-COR, respectively, are shown to be potent inhibitors of asparaginyl endopeptidases (legumains) from the bloodfluke, Schistosoma mansoni (SmAE), and the hard tick, Ixodes ricinus (IrAE). Structure-activity relationships (SARs) were determined for a set of 41 aza-peptide Michael acceptors and eight aza-peptide epoxides. Both enzymes prefer disubstituted amides to monosubstituted amides in the P1' position, and potency increased as we increased the hydrophobicity of the inhibitor in this position. Extending the inhibitor to P5 resulted in increased potency, especially against IrAE, and both enzymes prefer small over large hydrophobic residues at P2. Aza-peptide Michael acceptor inhibitors are more potent than aza-peptide epoxide inhibitors, and for some of these compounds, second-order inhibiton rate constants are the fastest yet discovered. Given the central functions of these enzymes in both parasites, the data presented here may facilitate the eventual design of selective antiparasitic drugs.
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- 2009
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237. SmCL3, a gastrodermal cysteine protease of the human blood fluke Schistosoma mansoni.
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Dvorák J, Mashiyama ST, Sajid M, Braschi S, Delcroix M, Schneider EL, McKerrow WH, Bahgat M, Hansell E, Babbitt PC, Craik CS, McKerrow JH, and Caffrey CR
- Subjects
- Amino Acid Sequence, Animals, Cathepsin L genetics, Cricetinae, DNA, Protozoan genetics, Enzyme Stability, Expressed Sequence Tags, Gastrointestinal Tract chemistry, Gene Expression, Hemoglobins metabolism, Humans, Hydrogen-Ion Concentration, Models, Molecular, Molecular Sequence Data, Phylogeny, Pichia genetics, Polymerase Chain Reaction methods, Protease Inhibitors pharmacology, Schistosoma mansoni genetics, Sequence Homology, Amino Acid, Serum Albumin metabolism, Snails, Substrate Specificity, Cathepsin L isolation & purification, Cathepsin L metabolism, Schistosoma mansoni enzymology
- Abstract
Background: Blood flukes of the genus Schistosoma are platyhelminth parasites that infect 200 million people worldwide. Digestion of nutrients from the host bloodstream is essential for parasite development and reproduction. A network of proteolytic enzymes (proteases) facilitates hydrolysis of host hemoglobin and serum proteins., Methodology/principal Findings: We identified a new cathepsin L termed SmCL3 using PCR strategies based on S. mansoni EST sequence data. An ortholog is present in Schistosoma japonicum. SmCL3 was heterologously expressed as an active enzyme in the yeast, Pichia pastoris. Recombinant SmCL3 has a broad pH activity range against peptidyl substrates and is inhibited by Clan CA protease inhibitors. Consistent with a function in degrading host proteins, SmCL3 hydrolyzes serum albumin and hemoglobin, is localized to the adult gastrodermis, and is expressed mainly in those life stages infecting the mammalian host. The predominant form of SmCL3 in the parasite exists as a zymogen, which is unusual for proteases. This zymogen includes an unusually long prodomain with alpha helical secondary structure motifs. The striking specificity of SmCL3 for amino acids with large aromatic side chains (Trp and Tyr) at the P2 substrate position, as determined with positional scanning-synthetic combinatorial library, is consistent with a molecular model that shows a large and deep S2 pocket. A sequence similarity network (SSN) view clusters SmCL3 and other cathepsins L in accordance with previous large-scale phylogenetic analyses that identify six super kingdoms., Conclusions/significance: SmCL3 is a gut-associated cathepsin L that may contribute to the network of proteases involved in degrading host blood proteins as nutrients. Furthermore, this enzyme exhibits some unusual sequence and biophysical features that may result in additional functions. The visualization of network inter-relationships among cathepsins L suggests that these enzymes are suitable 'marker sequences' for inclusion in future phylogenetic analyses.
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- 2009
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238. [Evaluation of surgical repair of distal biceps tendon ruptures].
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Behounek J, Hrubina M, Skoták M, Krumpl O, Zahálka M, Dvorák J, and Fucík M
- Subjects
- Adult, Aged, Humans, Male, Middle Aged, Radius surgery, Rupture, Elbow Joint surgery, Tendon Injuries surgery, Tendons surgery
- Abstract
PURPOSE OF THE STUDY To present the results of surgical repair of ruptures of the distal tendon of the biceps brachii muscle and thus show the adequacy of this treatment. MATERIAL Between 1987 and 2006, 19 patients had surgery for distal biceps tendon rupture. Only one side was affected in each patient. All patients were men between 28 and 69 years (average age, 47.5 years) at the time of injury (surgery). When the patients were evaluated at the end of 2007, 18 patients were included, because one died a year after surgery. METHODS The surgical repair always included a single-incision anatomical reattachment into the radial tuberosity. In 11 patients, a modified Mac Reynolds method with screw and washer fixation was used; in seven patients the insertion was fixed with Mitek anchors and, in one, it was sutured to the adjacent soft tissues. The average follow-up was 7 years (range, 1 to 20.5 years). The patients were evaluated for the cause of injury, their physical activity, age, dominance of the injured arm, surgical procedure and complications. RESULTS In 18 patients surgical repair was done early and, in one, at 16 days after injury. In all of them the tendon was detached from its site of insertion, but never torn. The intra-operative complications included, in one patient, bleeding owing to iatrogenic damage to a branch of the brachial artery, and difficult separation of the tendon due to its previous healed injury in another patient. Early post-operative complications included superficial skin necrosis in one patient and transient neurological deficit of the dorsal brand of the radial nerve and of the lateral cutaneous nerve of the forearm in two and one patient, respectively. The late complications were heterotropic ossification in three patients and screw migration in the one treated by the Mac Reynolds method. Excellent results were recorded in 11 patients (61 %), and good outcomes with a slight restriction of motion or muscle strength not limiting the patient's physical activities were in six (33.5 %) patients; only one patient (5.5 %) experienced pain on moderate exercise and had recurrent heterotropic ossification. Apart from this condition, there was no difference in the frequency of complications associated with the method used. DISCUSSION Only sparse information on distal biceps tendon ruptures has been available in the relevant Czech literature and, if so, only small groups with short follow-ups have been involved. Conservative treatment or the methods of non-anatomical reattachment have poor functional outcomes. Much better results are achieved by anatomical reattachment. Based on our experience with the Mac Reynolds technique, an anterior single-incision approach using fixation with Mitek anchors can be recommended. CONCLUSIONS Early surgical repair involving anatomical reattachment from the anterior singleincision approach with two Mitek anchors is recommended when a rupture of the distal tendon insertion of the biceps brachii is diagnosed. Key words: biceps radii muscle, biceps tendon injury, tendon fixation, bone screw and washer use.
- Published
- 2009
239. The functional expression and characterisation of a cysteine peptidase from the invasive stage of the neuropathogenic schistosome Trichobilharzia regenti.
- Author
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Dolecková K, Kasný M, Mikes L, Cartwright J, Jedelský P, Schneider EL, Dvorák J, Mountford AP, Craik CS, and Horák P
- Subjects
- Amino Acid Sequence, Animals, Blotting, Western, Cathepsin B biosynthesis, Cattle, Cysteine Proteases genetics, Ducks, Humans, Mice, Mice, Inbred BALB C, Molecular Sequence Data, Pichia, Rabbits, Schistosoma mansoni enzymology, Snails, Substrate Specificity, Turkeys, Cysteine biosynthesis, Cysteine Proteases biosynthesis, Cysteine Proteases physiology, Schistosoma enzymology
- Abstract
A transcriptional product of a gene encoding cathepsin B-like peptidase in the bird schistosome Trichobilharzia regenti was identified and cloned. The enzyme was named TrCB2 due to its 77% sequence similarity to cathepsin B2 from the important human parasite Schistosoma mansoni. The zymogen was expressed in the methylotropic yeast Pichia pastoris; procathepsin B2 underwent self-processing in yeast media. The peptidolytic activity of the recombinant enzyme was characterised using synthetic fluorogenic peptide substrates at optimal pH 6.0. Functional studies using different specific inhibitors proved the typical cathepsin B-like nature of the enzyme. The S(2) subsite specificity profile of recombinant TrCB2 was obtained. Using monospecific antibodies against the recombinant enzyme, the presence of cathepsin B2 was confirmed in extracts from cercariae (infective stage) and schistosomula (early post-cercarial stage) of T. regenti on Western blots. Also, cross-reactivity was observed between T. regenti and S. mansoni cathepsins B2 in extracts of cercariae, schistosomula or adults. In T. regenti, the antisera localised the enzyme to post-acetabular penetration glands of cercariae implying an important role in the penetration of host skin. The ability of recombinant TrCB2 to degrade skin, serum and nervous tissue proteins was evident. Elastinolytic activity suggests that the enzyme might functionally substitute the histolytic role of the serine class elastase known from S. mansoni and Schistosoma haematobium but not found in Schistosoma japonicum or in bird schistosomes.
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- 2009
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240. Chapter 4. Peptidases of trematodes.
- Author
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Kasný M, Mikes L, Hampl V, Dvorák J, Caffrey CR, Dalton JP, and Horák P
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- Animals, Host-Parasite Interactions, Humans, Trematode Infections parasitology, Trematode Infections veterinary, Virulence Factors genetics, Virulence Factors metabolism, Peptide Hydrolases genetics, Peptide Hydrolases metabolism, Trematoda enzymology
- Abstract
Among human and veterinary parasitic diseases the trematodiases (e.g. schistosomiasis, fascioliasis) represent a problem of global importance with vast social, economic and public health impacts, especially in developing countries. Therefore, host-parasite (host-trematode) interactions represent a key topic in many research laboratories, and modern approaches and technologies allow us to study the molecular basis of these interactions. As a consequence, key molecules produced by trematodes in order to ensure parasite invasion and survival within a hosts can be characterized. Trematode peptidases certainly belong to such molecules; as they are indispensable biocatalysts in a number of basal biological processes in trematodes (e.g. tissue invasion/migration, nutrition, immune evasion or other host-parasite interactions). Schistosoma mansoni cercarial elastase (CE) (penetration enzyme), cathepsin B (CB) (mainly nutrition enzyme) and Fasciola hepatica cathepsin L (CL) (nutrition, immune evasion enzyme) are probably the most studied trematode peptidases with well-characterized critical functions. Due to the importance of peptidases in host-parasite interactions they are considered to be promising targets for the development of novel chemotherapeutic drugs and vaccines against a number of trematodiases, including schistosomiasis, fascioliasis, paragonimiasis and opisthorchiasis. The present chapter summarizes the data on the biochemical and molecular features of the major trematode peptidases, and describes their role in trematode biology and host-parasite interactions based on proteolysis (peptidolysis).
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- 2009
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241. Intestinal permeability and vitamin A absorption in patients with chemotherapy-induced diarrhea.
- Author
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Melichar B, Dvorák J, Krcmová L, Hyspler R, Urbánek L, and Solichová D
- Subjects
- Adult, Aged, Aged, 80 and over, Case-Control Studies, Diarrhea drug therapy, Diarrhea metabolism, Female, Gastrointestinal Stromal Tumors complications, Gastrointestinal Stromal Tumors pathology, Humans, Lactulose urine, Male, Mannitol urine, Middle Aged, Permeability, Prognosis, Rectal Neoplasms complications, Rectal Neoplasms pathology, Xylose urine, Young Adult, Antineoplastic Combined Chemotherapy Protocols adverse effects, Diarrhea chemically induced, Gastrointestinal Stromal Tumors drug therapy, Intestinal Absorption, Rectal Neoplasms drug therapy, Vitamin A metabolism
- Abstract
Objective: Gastrointestinal toxicity is one of the most common side effects of anticancer therapy. Measurement of intestinal permeability represents one of the potential methods of noninvasive laboratory assessment of gastrointestinal toxicity. The aim of the present study was to investigate intestinal permeability and vitamin A absorption in patients with chemotherapy-induced diarrhea (CID)., Methods: We have assessed intestinal permeability, by measuring absorption of lactulose, mannitol, xylose, and vitamin A absorption, in 11 patients with CID, 10 healthy controls, and 24 untreated patients with gastrointestinal tumors. Urinary lactulose, mannitol and xylose were measured by capillary gas chromatography and serum retinol and retinyl esters were determined by high performance liquid chromatography. The results obtained in patients and controls were compared by Mann-Whitney U test., Results: Lactulose/mannitol and lactulose/xylose ratios were increased and retinol esters (retinyl palmitate and retinyl stearate) were decreased significantly in patients with CID., Conclusions: Measurements of intestinal permeability and vitamin A absorption may represent sensitive tools in the assessment of CID.
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- 2008
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242. Intestinal permeability and toxicity of second-line therapeutic agents in ovarian cancer.
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Melichar B, Hyspler R, Dragounová E, Kalábová H, and Dvorák J
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- Adult, Aged, Antineoplastic Combined Chemotherapy Protocols administration & dosage, Biomarkers metabolism, Camptothecin administration & dosage, Camptothecin analogs & derivatives, Cisplatin administration & dosage, Deoxycytidine administration & dosage, Deoxycytidine analogs & derivatives, Drug Administration Schedule, Female, Fluorouracil administration & dosage, Humans, Irinotecan, Lactulose blood, Lactulose urine, Leucovorin administration & dosage, Mannitol blood, Mannitol urine, Middle Aged, Permeability, Topotecan administration & dosage, Gemcitabine, Antineoplastic Combined Chemotherapy Protocols pharmacology, Carcinoma drug therapy, Carcinoma metabolism, Intestinal Mucosa metabolism, Lactulose metabolism, Mannitol metabolism, Ovarian Neoplasms drug therapy, Ovarian Neoplasms metabolism
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- 2008
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243. Aza-peptidyl Michael acceptors. A new class of potent and selective inhibitors of asparaginyl endopeptidases (legumains) from evolutionarily diverse pathogens.
- Author
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Götz MG, James KE, Hansell E, Dvorák J, Seshaadri A, Sojka D, Kopácek P, McKerrow JH, Caffrey CR, and Powers JC
- Subjects
- Animals, Aza Compounds chemistry, Biotin chemistry, Cysteine Proteinase Inhibitors chemistry, Dithiothreitol chemistry, Inhibitory Concentration 50, Oligopeptides chemistry, Structure-Activity Relationship, Sulfhydryl Compounds chemistry, Aza Compounds chemical synthesis, Cysteine Endopeptidases chemistry, Cysteine Proteinase Inhibitors chemical synthesis, Ixodes enzymology, Oligopeptides chemical synthesis, Schistosoma mansoni enzymology, Trichomonas vaginalis enzymology
- Abstract
Aza-peptide Michael acceptors with the general structure of Cbz-Ala-Ala-AAsn- trans-CH=CHCOR are a new class of inhibitors specific for the asparaginyl endopeptidases (AE) (legumains). Structure-activity relationships (SARs) were characterized for a set of 31 aza-peptide Michael acceptors with AEs derived from three medically important parasites: the protist Trichomonas vaginalis, the hard tick Ixodes ricinus, and the flatworm Schistosoma mansoni. Despite arising from phylogenetically disparate organisms, all three AEs shared a remarkably similar SAR with lowest IC50 values extending into the picomolar range. The results suggest an evolutionary constraint on the topography of the prime side of the active site. SAR also revealed that esters in the P1' position are more potent than disubstituted amides and that monosubstituted amides and alkyl derivatives show little or no inhibition. The preferred P1' residues have aromatic substituents. Aza-asparaginyl Michael acceptors react with thiols, which provides insight into the mechanism of their inhibition of asparaginyl endopeptidases.
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- 2008
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244. Differential use of protease families for invasion by schistosome cercariae.
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Dvorák J, Mashiyama ST, Braschi S, Sajid M, Knudsen GM, Hansell E, Lim KC, Hsieh I, Bahgat M, Mackenzie B, Medzihradszky KF, Babbitt PC, Caffrey CR, and McKerrow JH
- Subjects
- Animals, Cathepsin B chemistry, Chymotrypsin metabolism, Gene Transfer, Horizontal, Larva enzymology, Larva pathogenicity, Mass Spectrometry, Phylogeny, Proteomics, Schistosoma japonicum growth & development, Schistosoma japonicum pathogenicity, Schistosomatidae enzymology, Serine Endopeptidases classification, Serine Endopeptidases genetics, Species Specificity, Cathepsin B metabolism, Schistosoma japonicum enzymology, Schistosoma mansoni enzymology, Serine Endopeptidases metabolism
- Abstract
Schistosomes are parasitic platyhelminths (flatworms) of birds and mammals. As a parasitic disease of humans, schistosomiasis ranks second only to malaria in global importance. Schistosome larvae (cercariae) must invade and penetrate skin as an initial step to successful infection of the vertebrate host. Proteolytic enzymes secreted from the acetabular glands of cercariae contribute significantly to the invasion process. In this comparative study, we analyzed protease activities secreted by cercariae of Schistosoma mansoni, Schistosoma japonicum and Schistosomatium douthitti. Using protease-family specific, irreversible active-site probes, fluorogenic peptidyl substrates, immuno-histochemistry and high-resolution mass spectrometry, considerable species differences were noted in the quantity and character of proteases. Serine proteases, the most abundant enzymes secreted by S. mansoni cercariae, were not identified in S. japonicum. In contrast, the acetabular gland contents of S. japonicum cercariae had a 40-fold greater cathepsin B-like activity than those of S. mansoni. Based on the present data and previous reports, we propose that cysteine proteases represent an archetypal tool for tissue invasion among primitive metazoa and the use of serine proteases arose later in schistosome evolution. Computational analysis of serine protease phylogeny revealed an extraordinarily distant relationship between S. mansoni serine proteases and other members of the Clan PA family S1 proteases.
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- 2008
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245. Synthesis, antimycobacterial and antifungal evaluation of 3-arylaminopyrazine-2,5-dicarbonitriles.
- Author
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Palek L, Dvorák J, Svobodová M, Buchta V, Jampílek J, and Dolezal M
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- Absidia drug effects, Antifungal Agents pharmacology, Antitubercular Agents pharmacology, Aspergillus fumigatus drug effects, Candida drug effects, Chromatography, High Pressure Liquid, Microbial Sensitivity Tests, Mycobacterium drug effects, Nitriles pharmacology, Pyrazinamide pharmacology, Pyrazines pharmacology, Structure-Activity Relationship, Trichosporon drug effects, Antifungal Agents chemical synthesis, Antitubercular Agents chemical synthesis, Nitriles chemical synthesis, Pyrazinamide analogs & derivatives, Pyrazinamide chemical synthesis, Pyrazines chemical synthesis
- Abstract
This paper describes preparation and biological evaluation of pyrazinamide analogues. Pyrazinamide with its simple structure gives a good opportunity for further modification regarding an increase of its antimycobacterial activity. We prepared a series of compounds derived from pyrazine-2,5-dicarbonitrile with arylamino substitution in position 3. All compounds were assayed in vitro against major Mycobacterium and various Fungi species. The best activity was found in 3-{[3-(trifluoromethyl)phenyl]amino}pyrazine-2,5-dicarbonitrile 11 with the value of 6.25 micromol(-1) against M. tuberculosis H(37)Rv and moderate activity against minor Mycobacterium pathogens.
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- 2008
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246. Gastrointestinal permeability in ovarian cancer and breast cancer patients treated with paclitaxel and platinum.
- Author
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Melichar B, Hyspler R, Dragounová E, Dvorák J, Kalábová H, and Tichá A
- Subjects
- Adenocarcinoma drug therapy, Adenocarcinoma metabolism, Adenocarcinoma pathology, Adult, Aged, Antibodies, Monoclonal administration & dosage, Antibodies, Monoclonal, Humanized, Breast Neoplasms metabolism, Breast Neoplasms pathology, Carboplatin administration & dosage, Cisplatin administration & dosage, Female, Humans, Intestinal Absorption drug effects, Lactulose metabolism, Mannitol metabolism, Middle Aged, Neoplasms, Glandular and Epithelial drug therapy, Neoplasms, Glandular and Epithelial metabolism, Neoplasms, Glandular and Epithelial pathology, Ovarian Neoplasms metabolism, Ovarian Neoplasms pathology, Paclitaxel administration & dosage, Sucrose metabolism, Trastuzumab, Xylose metabolism, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Breast Neoplasms drug therapy, Cell Membrane Permeability drug effects, Gastrointestinal Tract metabolism, Ovarian Neoplasms drug therapy
- Abstract
Background: Combination of platinum derivatives with paclitaxel is currently the standard front line regimen for patients with epithelial ovarian carcinoma, and represents also an active regimen in patients with metastatic breast or unknown primary carcinomas. Measurement of intestinal permeability represents one of the potential methods of noninvasive laboratory assessment of gastrointestinal mucositis induced by chemotherapy, but little is known about intestinal permeability in patients treated with paclitaxel or platinum., Methods: Intestinal permeability was assessed in 36 breast and ovarian cancer patients treated with paclitaxel/platinum combination by measuring, using capillary gas chromatography, urinary sucrose, lactulose, xylose and mannitol after oral challenge. The significance of differences during the therapy compared to pre-treatment values was studied by Wilcoxon paired test. The differences between groups of patient were studied by Mann-Whitney U test. Fisher exact test was used to compare the frequency in different subgroups., Results: After administration of the first dose, a significant (p < 0.05) decrease in xylose absorption and increased lactulose/mannitol, sucrose/mannitol, lactulose/xylose and sucrose/xylose ratios were observed, but these parameters returned subsequently to pre-treatment levels. Patients who experienced serious (grade 3 or 4) toxicity had at baseline significantly lower percentages of xylose, mannitol and sucrose, and higher lactulose/mannitol ratio. Nine of 13 (69%) patients with baseline lactulose/mannitol ratio 0.070 or above experienced serious toxicity compared to 4 out of 23 patients (17%) with the ratio below 0.070 (p = 0.002). Post-treatment lactulose, lactulose/mannitol, sucrose/mannitol and lactulose/xylose ratios were significantly increased in patients with serious toxicity., Conclusion: A transient significant increase in lactulose/monosaccharide and sucrose/monosaccharide ratios was observed in ovarian and breast cancer patients treated with paclitaxel and platinum. Increased lactulose absorption, lactulose/mannitol, sucrose/mannitol and lactulose/xylose ratios were evident in patients with grade 3 or 4 toxicity, and increased baseline lactulose/mannitol ratio predicted serious toxicity.
- Published
- 2007
- Full Text
- View/download PDF
247. IrAE: an asparaginyl endopeptidase (legumain) in the gut of the hard tick Ixodes ricinus.
- Author
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Sojka D, Hajdusek O, Dvorák J, Sajid M, Franta Z, Schneider EL, Craik CS, Vancová M, Buresová V, Bogyo M, Sexton KB, McKerrow JH, Caffrey CR, and Kopácek P
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Cathepsin B metabolism, Cloning, Molecular, Cysteine Endopeptidases chemistry, Cysteine Endopeptidases isolation & purification, Cysteine Endopeptidases metabolism, Female, Fluorescent Antibody Technique, Indirect, Hemoglobins metabolism, Ixodes genetics, Microscopy, Electron, Transmission, Molecular Sequence Data, Phylogeny, Pichia genetics, Pichia metabolism, RNA, Messenger biosynthesis, RNA, Messenger genetics, Recombinant Proteins biosynthesis, Recombinant Proteins genetics, Reverse Transcriptase Polymerase Chain Reaction, Sequence Alignment, Cysteine Endopeptidases genetics, Digestive System enzymology, Ixodes enzymology
- Abstract
Ticks are ectoparasitic blood-feeders and important vectors for pathogens including arboviruses, rickettsiae, spirochetes and protozoa. As obligate blood-feeders, one possible strategy to retard disease transmission is disruption of the parasite's ability to digest host proteins. However, the constituent peptidases in the parasite gut and their potential interplay in the digestion of the blood meal are poorly understood. We have characterised a novel asparaginyl endopeptidase (legumain) from the hard tick Ixodes ricinus (termed IrAE), which we believe is the first such characterisation of a clan CD family C13 cysteine peptidase (protease) in arthropods. By RT-PCR of different tissues, IrAE mRNA was only expressed in the tick gut. Indirect immunofluorescence and EM localised IrAE in the digestive vesicles of gut cells and within the peritrophic matrix. IrAE was functionally expressed in Pichia pastoris and reacted with a specific peptidyl fluorogenic substrate, and acyloxymethyl ketone and aza-asparagine Michael acceptor inhibitors. IrAE activity was unstable at pH > or = 6.0 and was shown to have a strict specificity for asparagine at P1 using a positional scanning synthetic combinatorial library. The enzyme hydrolyzed protein substrates with a pH optimum of 4.5, consistent with the pH of gut cell digestive vesicles. Thus, IrAE cleaved the major protein of the blood meal, hemoglobin, to a predominant peptide of 4kDa. Also, IrAE trans-processed and activated the zymogen form of Schistosoma mansoni cathepsin B1 -- an enzyme contributing to hemoglobin digestion in the gut of that bloodfluke. The possible functions of IrAE in the gut digestive processes of I. ricinus are compared with those suggested for other hematophagous parasites.
- Published
- 2007
- Full Text
- View/download PDF
248. A multienzyme network functions in intestinal protein digestion by a platyhelminth parasite.
- Author
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Delcroix M, Sajid M, Caffrey CR, Lim KC, Dvorák J, Hsieh I, Bahgat M, Dissous C, and McKerrow JH
- Subjects
- Animals, Cathepsin B antagonists & inhibitors, Cathepsin D antagonists & inhibitors, Cathepsin L, Cathepsins antagonists & inhibitors, Cysteine Endopeptidases pharmacology, Enzyme Inhibitors pharmacology, Hemoglobins chemistry, Hydrogen-Ion Concentration, Mice, Mice, Inbred C57BL, Models, Biological, RNA, Double-Stranded chemistry, Intestines parasitology, Multienzyme Complexes metabolism, Schistosoma mansoni metabolism
- Abstract
Proteases frequently function not only as individual enzymes but also in cascades or networks. A notable evolutionary switch occurred in one such protease network that is involved in protein digestion in the intestine. In vertebrates, this is largely the work of trypsin family serine proteases, whereas in invertebrates, cysteine proteases of the papain family and aspartic proteases assume the role. Utilizing a combination of protease class-specific inhibitors and RNA interference, we deconvoluted such a network of major endopeptidases functioning in invertebrate intestinal protein digestion, using the parasitic helminth, Schistosoma mansoni as an experimental model. We show that initial degradation of host blood proteins is ordered, occasionally redundant, and substrate-specific. Although inhibition of parasite cathepsin D had a greater effect on primary cleavage of hemoglobin, inhibition of cathepsin B predominated in albumin degradation. Nevertheless, in both cases, inhibitor combinations were synergistic. An asparaginyl endopeptidase (legumain) also synergized with cathepsin B and L in protein digestion, either by zymogen activation or facilitating substrate cleavage. This protease network operates optimally in acidic pH compartments either in the gut lumen or in vacuoles of the intestinal lining cells. Defining the role of each of these major enzymes now provides a clearer understanding of the function of a complex protease network that is conserved throughout invertebrate evolution. It also provides insights into which of these proteases are logical targets for development of chemotherapy for schistosomiasis, a major global health problem.
- Published
- 2006
- Full Text
- View/download PDF
249. [Chronic postoperative endophthalmitis].
- Author
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Svozílková P, Ríhová E, Brichová M, Diblík P, Dvorák J, and Sach J
- Subjects
- Aged, Chronic Disease, Endophthalmitis etiology, Gram-Positive Bacterial Infections etiology, Humans, Male, Propionibacterium, Cataract Extraction adverse effects, Endophthalmitis therapy, Gram-Positive Bacterial Infections therapy
- Abstract
Purpose: To evaluate our experience with the diagnosis and the treatment of chronic postoperative endophthalmitis., Methods: A retrospective study., Results: The authors present three cases of chronic postoperative endophthalmitis following cataract surgery. Propionibacterium species has been determined as the causative agent in two patients. All patients were men; the mean age was 75 years (from 73 to 78 years). The mean time period from the cataract operation to the onset of intraocular inflammatory signs was 5 months (from 2 to 9 months). Pars plana vitrectomy with intravitreal administration of antibiotics and intraocular lens explantation with total capsulectomy were performed. This treatment led to the reduction of the intraocular inflammatory reaction and to the improvement of the visual acuity., Conclusion: The effective treatment of chronic postoperative endophthalmitis caused by Propionibacterium species is a combined operation--intraocular lens explantation with total capsulectomy and pars plana vitrectomy with intravitreal administration of antibiotics.
- Published
- 2006
250. [Tumor angiogenesis].
- Author
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Lukesová S, Kopecký O, Dvorák J, Hlávková D, and Vroblová V
- Subjects
- Animals, Humans, Neoplasms physiopathology, Neoplasms blood supply, Neovascularization, Pathologic physiopathology
- Abstract
Angiogenesis have shown a major role in tumor growth and metastasis formation. For tumor growth beyond the size 1-2 mm3, angiogenesis must be started to form vascular supply of tumor cells. Angiogenesis is a complex process, involving degradation of the basement membrane of preexisting vessel, proliferation of endothelial cells towards the angiogenetic stimulus, maturation of endothelial cells with formation of luminized capillary, and finally formation of a functional vessel, surrounded by basement membrane and pericytes. Angiogenesis is regulated by numerous angiogenic and anti-angiogenic factors. Hypoxia is a significant stimulus for angiogenesis. For many cancers the extent of vascularisation is a negative prognostic indicator signifying aggressive disease and increased potential for metastasis.
- Published
- 2006
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