37 results on '"M, Krsek"'
Search Results
2. Plasma ghrelin levels in patients with end-stage renal disease
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Z, Jarkovská, M, Rosická, M, Krsek, S, Sulková, M, Haluzík, V, Justová, Z, Lacinová, and J, Marek
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Leptin ,Male ,Human Growth Hormone ,Peptide Hormones ,Receptors, Cell Surface ,Middle Aged ,Ghrelin ,Insulin-Like Growth Factor Binding Protein 1 ,Insulin-Like Growth Factor Binding Protein 3 ,Renal Dialysis ,Creatinine ,Body Composition ,Humans ,Insulin ,Kidney Failure, Chronic ,Receptors, Leptin ,Female ,Insulin-Like Growth Factor I ,Insulin-Like Growth Factor Binding Protein 6 ,Aged - Abstract
Ghrelin is an acylated peptide stimulating secretion of the growth hormone (GH). It was originally isolated from the rat stomach as an endogenous ligand for the growth hormone secretagogue receptor. Although being predominantly produced by endocrine cells of the gastric fundus, its secretion has been found in various tissues including the kidney. To study the influence of renal failure on plasma ghrelin levels we examined 16 patients with end-stage renal disease (ESRD) receiving hemodialysis (8 men and 8 women) and 19 controls (10 men and 9 women). Both groups were comparable in age and BMI. In all subjects we assessed plasma levels of ghrelin, leptin, soluble leptin receptor, insulin, IGF-I, IGFBP-1, IGFBP-3 and IGFBP-6. Ghrelin levels were significantly higher in the group of dialyzed patients (4.49+/-0.74 vs. 1.79+/-0.15 ng/ml; p0.001). These patients had significantly higher levels of GH, IGFBP-1, IGFBP-6, leptin and percentage of body fat (p0.05). In the group of patients with ESRD plasma ghrelin levels positively correlated with IGFBP-1 (p0.01). In the control group, ghrelin positively correlated with GH concentrations (p0.01) and negatively correlated with the levels of insulin and creatinine (p0.05). In conclusion, patients with ESRD have higher ghrelin concentrations, which might be caused by a decreased excretion/metabolism of ghrelin in the kidney during renal failure.
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- 2004
3. Endocrine and metabolic activities of a recently isolated peptide hormone ghrelin, an endogenous ligand of the growth hormone secretagogue receptor
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Z, Jarkovska, M, Krsek, M, Rosicka, and J, Marek
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Peptide Hormones ,Animals ,Humans ,Growth Hormone-Releasing Hormone ,Ligands ,Receptors, Ghrelin ,Ghrelin ,Receptors, G-Protein-Coupled - Abstract
Ghrelin is a member of the group of growth hormone secretagogues (GHSs). It is a peptide hormone, recently isolated from stomach as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R). Ghrelin is mostly produced by the stomach, although its production has been proved in various tissues. It is a potent releaser of growth hormone (GH) from anterior pituitary cells, but it also stimulates the release of other hypophyseal hormones. Ghrelin stimulates food intake and induces metabolic changes leading to an increase in body weight and body fat mass. This effect seems to be independent of GH action and needs an intact NPY/AGRP (neuropeptide Y/agouti-related protein) system. Plasma ghrelin levels are decreased in obesity, elevated in cachexia and show a diurnal rhythm. Its preprandial elevation suggests, that it might be a signal for meal initiation. Ghrelin further stimulates the release of gastric acid and gastric motility and affects pancreatic functions. It has vasodilatatory, cardioprotective and antiproliferative effects. This article is focused on ghrelin's endocrine and metabolic functions.
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- 2004
4. Serum ghrelin levels in obese patients: the relationship to serum leptin levels and soluble leptin receptors levels
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M, Rosická, M, Krsek, M, Matoulek, Z, Jarkovská, J, Marek, V, Justová, and Z, Lacinová
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Adult ,Leptin ,Male ,Peptide Hormones ,Humans ,Receptors, Leptin ,Female ,Receptors, Cell Surface ,Obesity ,Middle Aged ,Ghrelin ,Body Mass Index - Abstract
Ghrelin is a new endogenous ligand for the growth hormone secretagogue receptor. It activates the release of growth hormone from the pituitary and it also participates in the regulation of energy homeostasis. The aim of the study was to characterize changes in serum ghrelin levels in obese subjects and their relationship to the serum levels of leptin and soluble leptin receptor. Eight obese patients (6 women and 2 men) with body mass index (BMI) 40.3+/-13.4 kg.m(-2) and eight healthy controls (5 women and 3 men) with BMI 22.7+/-1.3 kg.m(-2) were examined. The ghrelin serum levels (165.0+/-58.1 vs. 343.37+/-81.96; p0.001) and soluble leptin receptor serum levels (7.25+/-3.44 vs. 21.80+/-4.99; p0.0001) were significantly lower in obese patients. The leptin serum levels (23.45+/-12.90 vs. 6.41+/-2.96; p0.005) were significantly higher compared to the lean subject group. In both measured groups the levels of serum leptin significantly positively correlated with BMI. We proved a significantly lower serum ghrelin levels in the group of obese patients in comparison with the control group.
- Published
- 2003
5. Ghrelin -- a new endogenous growth hormone secretagogue
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M, Rosická, M, Krsek, Z, Jarkovská, J, Marek, and V, Schreiber
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Human Growth Hormone ,Peptide Hormones ,Animals ,Humans ,Neurosecretory Systems ,Ghrelin - Abstract
Ghrelin is a new endogenous peptide, discovered in 1999 by Kojima et al., as the result of a search for an endogenous ligand for an orphan receptor of known structure and function. Ghrelin is composed of 28 amino acids and is produced mostly by cells of the stomach, hypothalamus, and hypophysis, but it has also been detected in other tissues. Its discovery is related to the development of a new hypothesis regarding the regulation of growth hormone secretion. It is an antagonist of somatostatin. Ghrelin activates the release of growth hormone from the somatotrophic cells of the hypophysis. It participates in the regulation of energy homeostasis, increases food intake, decreases energy output and exerts a lipogenetic effect. Its metabolic effects do not depend on the GH/IGF-I system, but are mediated by the NPY/Y1 and AGRP receptor system. Ghrelin influences the secretion and motility of the gastrointestinal tract, especially the stomach. The presence of ghrelin and its receptors has also been demonstrated in many other tissues. Its function in these tissues has not yet been studied, thus providing many possibilities for further research.
- Published
- 2002
6. The relationship between the IGF-I system and its binding proteins and microvascular reactivity in Type 1 diabetes mellitus
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M, Krsek, M, Prázný, J, Skrha, V, Justová, Z, Lacinová, and T, Haas
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Insulin-Like Growth Factor Binding Proteins ,Male ,Diabetes Mellitus, Type 1 ,Reference Values ,Microcirculation ,Blood Circulation ,Laser-Doppler Flowmetry ,Humans ,Female ,Insulin-Like Growth Factor I ,Middle Aged - Abstract
The system of IGF-I and its binding proteins may be involved in the pathogenesis of vascular damage in Type 1 diabetes. The aim of this study was to analyze the relationship between this system and the microvascular reactivity in Type 1 diabetes as measured by laser-Doppler flowmetry. Twenty-two Type 1 diabetic patients (13 women and 9 men) with microangiopathy and fifteen healthy subjects (8 women and 7 men) were examined clinically, underwent laser-Doppler flowmetry and intima-media thickness measurements. Fasting serum levels of IGF-I, free IGF-I, IGFBPs and lipids were examined. The microvascular reactivity was impaired in Type 1 diabetic patients. Maximal perfusion during post-occlusive reactive hyperemia (PORHmax) and during thermal hyperemia (THmax) was significantly decreased in Type 1 diabetes (p0.01). Percentage perfusion increase in both tests (PORH and TH) was lower in Type 1 diabetes mellitus (p0.01) and the reaction after heating was slower in diabetic patients (THmax) (p0.01). We did not find any significant dependence of microvascular reactivity on the parameters of IGF-I or its binding proteins. We conclude that the microvascular reactivity is impaired in Type 1 diabetes mellitus, but this impairment is not clearly dependent on the activity of the IGF-I system. It is probably only a complementary pathogenic factor.
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- 2002
7. Adrenal insufficiency - causes and laboratory diagnosis.
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Brutvan T, Jezkova J, Kotasova M, and Krsek M
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Adrenal insufficiency (AI) manifests as a clinical syndrome arising from either the direct impairment of adrenal glands, leading to primary AI characterized by deficiencies in glucocorticoids and mineralocorticoids, or adrenal cortex atrophy due to diminished adrenocorticotropic hormone (ACTH) stimulation, a consequence of hypothalamic and/or pituitary damage, resulting in secondary AI. The diagnosis of AI is based on clinical assessment and biochemical tests, including basal hormone level measurements and stimulation tests. In evaluating the results of laboratory tests, it is necessary to consider factors that may influence both pre-analytical and analytical phases, as well as the chosen methodology. Correct diagnosis of adrenal insufficiency and timely initiation of suitable replacement therapy are paramount. These steps are crucial not only for managing the condition but also to avert potentially life-threatening adrenal crises., Competing Interests: The authors report no conflicts of interest in this work.
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- 2024
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8. Pediatric Cushing's disease: Case reports and retrospective review.
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Pomahacova R, Paterova P, Nykodymova E, Sykora J, and Krsek M
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- Adult, Female, Male, Humans, Child, Retrospective Studies, Czech Republic, Growth Disorders, Diagnosis, Differential, Pituitary ACTH Hypersecretion diagnosis, Pituitary Neoplasms
- Abstract
Background: We report four pediatric subjects with Cushing's disease (CD) diagnosed in the Czech Republic. We focus on initial symptoms of Cushing's syndrome (CS) which can lead to early diagnosis, on typical symptoms of CS in children, their age and sex distribution, the mean length of symptoms prior to diagnosis, indication for examination, post-cure growth, sexual development and pituitary function in our four CD patients after transsphenoidal pituitary surgery (TSS). We describe the diagnostic process leading to confirmation of CD and we emphasize the biochemical and radiological diagnostic difficulties., Conclusions: Pediatric CD has a number of features distinct from adult CD. Our retrospective analysis confirmed the presence of growth retardation and change in facial appearance with development of moon face as the first symptoms of CS. According to our observation, growth retardation is prior to development of moon face. The other typical symptoms frequently seen in pediatric patients are pseudo-precocious puberty in both sexes, hirsutism in pubertal girls due to excessive adrenal androgen secretion and pubertal delay. A corticotropin-releasing hormone (CRH) test and especially bilateral inferior petrosal sinus sampling for ACTH (BIPSS) contribute to confirming the diagnosis of CD and excluding ectopic ACTH syndrome in children with unvisible adenoma on pituitary magnetic resonance imaging (MRI)., Competing Interests: The authors report no conflicts of interest in this work.
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- 2024
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9. Oral Health Knowledge, Attitudes, and Behaviors (KAB) of German Dental Students: Descriptive Cross-Sectional Study.
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Riad A, Buchbender M, Howaldt HP, Klugar M, Krsek M, and Attia S
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Germany's 2030-oral health agenda incorporates behavioral targets such as twice-daily toothbrushing and routine dental check-ups. Given the professional and social roles of dentists in oral health promotion, the oral health-related knowledge, attitudes, and behaviors (KAB) of dentists and dental students became worth investigation. The present study was designed as a descriptive cross-sectional study that aimed to evaluate oral health KAB of German dental students using the Hiroshima University - Dental Behavioral Inventory (HU-DBI). A total of 508 dental students filled in the questionnaire, out of which 74.2% were females, 38.8% were clinical students, 11.4% reported tobacco smoking at least once week, 26.6% reported drinking alcohol at least once a week, and 82.9% reported suffering from problematic internet use. The overall HU-DBI score was high (7.67 ± 1.32), and it was slightly higher among females (7.70 ± 1.33) than males (7.59 ± 1.29), and gender-diverse students (7.33 ± 1.37). Clinical students (7.88 ± 1.26) had a significantly higher HU-DBI score, especially in the domain of oral health behaviors, compared with preclinical students (7.53 ± 1.34). A significant improvement in oral health behaviors and HU-DBI score was found between the third- vs . the fourth year, which corresponds to the period when prophylaxis, hygiene, and periodontology courses are delivered. Tobacco smoking was significantly associated with poor oral health knowledge, behaviors, and overall HU-DBI score. Problematic internet use and alcohol drinking had slightly lower HU-DBI scores. The findings of the present study call for early implementation of preventive dentistry elements in German curricula and addressing oral health needs of gender minorities in Germany by future epidemiologic studies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Riad, Buchbender, Howaldt, Klugar, Krsek and Attia.)
- Published
- 2022
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10. Tumor induced osteomalacia - A long way toward correct diagnosis and management.
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Filipová L, Zikán V, Krsek M, Netuka D, Michal M, and Lazúrová I
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Tumor-induced osteomalacia (TIO) is an uncommon type of osteomalacia associated with phosphaturic mesenchymal tumors (PMTs). Due to nonspecific symptoms, the diagnosis and appropriate management of the disease is often delayed for many years. Involvement of spine with TIO associated tumors is exceedingly rare. We present a 53-year-old woman with a 10-year history of bone pain, muscle weakness and multiple bone fractures that markedly impaired her quality of life. Biochemical evaluation revealed hypophosphatemia due to renal phosphate wasting and elevated plasma fibroblast growth factor 23 (FGF-23) concentration indicating PMT. It was found using
68 Ga DOTA TOC PET/CT scan in the vertebral body L2. The patient underwent surgical resection of the tumor. Postoperatively, there was a significant decrease in phosphaturia, normalization of serum phosphate, 1.25 dihydroxyvitamin D and plasma FGF23 concentration. Thereafter the patient's condition markedly improved concerning her motility and basic daily activities. This case report demonstrates the first known case of TIO in the Slovakia and points to a long way from onset of symptoms toward correct diagnosis and successful surgical management., Competing Interests: The authors declare that the case report description was realized in the absence of any commercial or financial relationship that could represent a potential conflict of interest., (© 2022 Published by Elsevier Inc.)- Published
- 2022
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11. Czech and Slovak Dental Students' Oral Health-Related Knowledge, Attitudes, and Behaviours (KAB): Multi-Country Cross-Sectional Study.
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Riad A, Chuchmová V, Staněk J, Hocková B, Attia S, Krsek M, and Klugar M
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- Cross-Sectional Studies, Czech Republic, Female, Health Behavior, Health Knowledge, Attitudes, Practice, Humans, Oral Hygiene, Slovakia, Surveys and Questionnaires, Oral Health, Students, Dental
- Abstract
Dentists play a key role in the primary prevention of oral diseases and related systemic complications; therefore, their views on behavioural interventions need to be aligned with the current agendas for oral health. Likewise, dental students' oral health-related knowledge, attitudes, and behaviours (KAB) are of practical importance, as they are the future opinion leaders for oral health in their respective communities. A cross-sectional survey-based study was designed to evaluate the oral health KAB of dental students in both the Czech Republic and Slovakia. The study utilized translated versions of the Hiroshima University Dental Behavioural Inventory (HU-DBI), and it aimed to recruit students from all Czech and Slovak dental schools. A total of 487 students were included in this study, out of which 372 (76.4%) were females, 271 (55.6%) were enrolled in preclinical years, 68 (14%) reported smoking tobacco at least once a week, and 430 (88.3%) reported problematic internet use. The mean HU-DBI score of Czech and Slovak dental students (8.18 ± 1.80) was comparable with the previously reported scores of dental students in Nordic and Western European countries. Czech students (9.34 ± 1.29) had a significantly higher score than their Slovak counterparts (7.56 ± 1.73). In both countries, preclinical students (8.04 vs. 8.35), the students who reported tobacco smoking (7.63 vs. 8.27), and those who reported problematic internet use (8.11 vs. 8.70) had significantly lower HU-DBI scores than their counterparts, respectively. In the Czech Republic, the significant increases in HU-DBI scores occurred after the first academic year when the students received preventive dentistry courses; therefore, one can put forward that early implementation of preventive elements in undergraduate dental curricula may yield better and more sustainable oral health gains for the students. Future research on Czech and Slovak dental curricula need to re-evaluate the oral hygiene and anti-smoking components and their impact on students' views and attitudes., Competing Interests: The authors declare no conflict of interest.
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- 2022
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12. Estonian Dental Students' Oral Health-Related Knowledge, Attitudes and Behaviours (KAB): National Survey-Based Study.
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Riad A, Põld A, Olak J, Howaldt HP, Klugar M, Krsek M, and Attia S
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- Cross-Sectional Studies, Estonia epidemiology, Female, Health Behavior, Health Knowledge, Attitudes, Practice, Humans, Male, Oral Hygiene, Surveys and Questionnaires, Oral Health, Students, Dental
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The strategic plan for dentistry and oral health in Estonia of 2030 focuses on oral health promotion and disease prevention through undergraduate dental curricula and fostering public health-oriented research among students. The present study was designed as a descriptive cross-sectional study to evaluate oral health-related knowledge, attitudes, and behaviours (KAB) of dental students in Estonia. The study was carried out in the spring semester of 2020, and it used a modified version of the Hiroshima University Dental Behavioural Inventory (HU-DBI). A total of 129 students responded to the survey, constituting a response rate of 93.5% due to the total population sampling (census) technique used in this study and the small target population size. Out of the 124 students included in the final analysis, 79% were females, 62.1% were clinical students, 11.3% reported smoking tobacco at least once a week, and 86.3% reported problematic internet use. The present study found that mean HU-DBI score of Estonian dental students was 8.09 ± 1.22 which is so far the highest recorded HU-DBI score in Europe. There was no significant difference between female vs. male or preclinical vs. clinical students in terms of HU-DBI score. While clinical students reported less faulty oral hygiene practices, such as hard toothbrush use and aggressive toothbrushing, preclinical students reported a slightly higher mean HU-DBI score. Smoking behaviour was more common among male and clinical students, and it was also associated with alcohol drinking and worry about teeth colour and halitosis.
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- 2022
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13. Oral Health-Related Knowledge, Attitudes and Behaviours of Arab Dental Students: Multi-National Cross-Sectional Study and Literature Analysis 2000-2020.
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Riad A, Al-Khanati NM, Issa J, Zenati M, Abdesslem NB, Attia S, and Krsek M
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- Arabs, Cross-Sectional Studies, Female, Health Behavior, Health Knowledge, Attitudes, Practice, Humans, Lebanon epidemiology, Male, Oral Hygiene, Surveys and Questionnaires, Oral Health, Students, Dental
- Abstract
Dental students are the future leaders of oral health in their respective communities; therefore, their oral health-related attitudes and behaviours are of practical value for primary disease prevention. The present study aimed to evaluate oral health-related knowledge, attitudes, and behaviours of dental students in Arab countries and explore the potential sociodemographic predictors of their oral health outcomes. A multi-centre, cross-sectional study was conducted during the academic year 2019/2020 in three Arab countries: Lebanon, Syria, and Tunisia. The study used a validated Arabic version of the Hiroshima University Dental Behavioural Inventory (HU-DBI) composed of original twenty items that assess the level of oral health-related knowledge, attitudes, and behaviours, and four additional dichotomous items related to tobacco smoking, alcohol drinking, problematic internet use, and regular dental check-up The HU-DBI score ranges between 0 and 12. A total of 1430 students took part in this study, out of which 60.8% were females, 57.8% were enrolled in clinical years, 24.5% were tobacco smokers, 7.2% were alcohol drinkers, and 87% reported internet addiction. The mean HU-DBI score was 6.31 ± 1.84, with Lebanon having the highest score (6.67 ± 1.83), followed by Syria (6.38 ± 1.83) and Tunisia (6.05 ± 1.83). Clinical students (6.78 ± 1.70) had higher HU-DBI scores than their preclinical peers (5.97 ± 1.86). The year-over-year analysis revealed that dental public health and preventive dentistry courses had significantly and positively impacted the undergraduate students' knowledge, attitudes, and behaviours. The gender-based differences were not statistically significant, with a modest trend favouring males, especially oral health behaviours. Tobacco smoking, alcohol drinking, and problematic internet use were associated with lower HU-DBI scores. In the Arab world, the economic rank of the country where the dental students live/study was weakly correlated with the students' mean HU-DBI score.
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- 2022
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14. Oral Health-Related Knowledge, Attitudes and Behaviours of Elementary School Teachers.
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Yılmaz G, Riad A, Krsek M, Kurt H, and Attia S
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- Cross-Sectional Studies, Female, Health Education, Dental, Humans, Male, Oral Health, Surveys and Questionnaires, Health Knowledge, Attitudes, Practice, School Teachers
- Abstract
Background: elementary schoolteachers play a central role in shaping their students' beliefs, attitudes, and behaviours related to health and oral hygiene. This study was designed to evaluate Turkish schoolteachers' levels of oral health knowledge, attitudes, and behaviours., Methods: A cross-sectional survey-based study was conducted among elementary schoolteachers in Istanbul using a validated self-administered questionnaire. The questionnaire was composed of 36 multiple-choice items categorised into six sections, and the participants were recruited using convenience sampling. (3) Results: A total of 385 elementary schoolteachers participated in this study. The majority were female (62.2%), qualified with a licensure degree (81.3%) and working in public schools (86.5%). Female gender and greater work experience were found to be promoters for oral health knowledge and positive attitudes. The correlation between their perceived knowledge and actual knowledge was very weak, thus suggesting that the teachers are inclined to overestimate their knowledge., Conclusions: The Turkish elementary schoolteachers showed satisfactory oral health knowledge and attitudes toward oral health education. The teachers' knowledge about dental trauma management was inadequate, necessitating urgent educational interventions, especially for physical education teachers, who are at the greatest risk of encountering such events during their work. The oral hygiene behaviours were not associated with teachers' oral health knowledge, attitudes, or practice, thus requiring further investigation.
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- 2021
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15. A Consensus on the Diagnosis and Treatment of Acromegaly Comorbidities: An Update.
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Giustina A, Barkan A, Beckers A, Biermasz N, Biller BMK, Boguszewski C, Bolanowski M, Bonert V, Bronstein MD, Casanueva FF, Clemmons D, Colao A, Ferone D, Fleseriu M, Frara S, Gadelha MR, Ghigo E, Gurnell M, Heaney AP, Ho K, Ioachimescu A, Katznelson L, Kelestimur F, Kopchick J, Krsek M, Lamberts S, Losa M, Luger A, Maffei P, Marazuela M, Mazziotti G, Mercado M, Mortini P, Neggers S, Pereira AM, Petersenn S, Puig-Domingo M, Salvatori R, Shimon I, Strasburger C, Tsagarakis S, van der Lely AJ, Wass J, Zatelli MC, and Melmed S
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- Acromegaly diagnosis, Comorbidity, Consensus, Humans, Acromegaly therapy, Practice Guidelines as Topic standards, Quality of Life
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Objective: The aim of the Acromegaly Consensus Group was to revise and update the consensus on diagnosis and treatment of acromegaly comorbidities last published in 2013., Participants: The Consensus Group, convened by 11 Steering Committee members, consisted of 45 experts in the medical and surgical management of acromegaly. The authors received no corporate funding or remuneration., Evidence: This evidence-based consensus was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence following critical discussion of the current literature on the diagnosis and treatment of acromegaly comorbidities., Consensus Process: Acromegaly Consensus Group participants conducted comprehensive literature searches for English-language papers on selected topics, reviewed brief presentations on each topic, and discussed current practice and recommendations in breakout groups. Consensus recommendations were developed based on all presentations and discussions. Members of the Scientific Committee graded the quality of the supporting evidence and the consensus recommendations using the GRADE system., Conclusions: Evidence-based approach consensus recommendations address important clinical issues regarding multidisciplinary management of acromegaly-related cardiovascular, endocrine, metabolic, and oncologic comorbidities, sleep apnea, and bone and joint disorders and their sequelae, as well as their effects on quality of life and mortality., (© Endocrine Society 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2020
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16. Characteristic CT features of pheochromocytomas - probability model calculation tool based on a multicentric study.
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Ctvrtlik F, Tudos Z, Szasz P, Sedlackova Z, Hartmann I, Schovanek J, Frysak Z, Macova I, Zelinka T, Hora M, Kocova E, Pacovsky J, Krsek M, Lehotska V, Mojtova E, Molnar J, Vanek V, Pacak K, and Baxa J
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- Adrenocortical Carcinoma diagnostic imaging, Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Models, Statistical, Neoplasm Metastasis, Regression Analysis, Tomography, Spiral Computed, Young Adult, Adrenal Gland Neoplasms diagnostic imaging, Pheochromocytoma diagnostic imaging
- Abstract
Objectives: The aim of the study was to evaluate the CT features of adrenal tumors in an effort to identify features specific to pheochromocytomas and second, to define a feasible probability calculation model., Methods: This multicentric retrospective study included patients from the period 2003 to 2017 with an appropriate CT examination and a histological diagnosis of an adrenal adenoma, pheochromocytoma, adrenocortical carcinoma, or metastasis. In total, 346 patients were suitable for the CT image analysis, which included evaluation of the largest diameter, the shape of the lesion, the presence of central necrosis and its margins, and the presence of an enhancing peripheral rim ("ring sign")., Results: Pheochromocytomas have a significantly more spherical shape (P<0.001), whereas an elliptical shape significantly reduces the probability of a pheochromocytoma (odds ratio = 0.015), as does another shape (odds ratio = 0.006). A "ring sign" is also more frequent in pheochromocytomas compared to other adrenal tumors (P=0.001, odds ratio = 6.49). A sharp necrosis also increases the probability of a pheochromocytoma more than unsharp necrosis (odds ratio 231.6 vs. 20.2). The probability calculation model created on the basis of the results confirms a high sensitivity and specificity (80% and 95%)., Conclusion: This study confirms the value of anatomical features in the assessment of adrenal masses with the ability to significantly improve the identification of pheochromocytomas. Advanced assessment of the tumor shape was defined and a original comprehensive calculating tool of the pheochromocytoma probability was created on the basis of the results presented here and could be used in clinical routine.
- Published
- 2019
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17. Stereotactic Radiosurgery for Cushing Disease: Results of an International, Multicenter Study.
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Mehta GU, Ding D, Patibandla MR, Kano H, Sisterson N, Su YH, Krsek M, Nabeel AM, El-Shehaby A, Kareem KA, Martinez-Moreno N, Mathieu D, McShane B, Blas K, Kondziolka D, Grills I, Lee JY, Martinez-Alvarez R, Reda WA, Liscak R, Lee CC, Lunsford LD, Vance ML, and Sheehan JP
- Subjects
- ACTH-Secreting Pituitary Adenoma metabolism, Adenoma metabolism, Adolescent, Adult, Aged, Aged, 80 and over, Child, Female, Follow-Up Studies, Humans, Male, Middle Aged, Retrospective Studies, Treatment Outcome, Young Adult, ACTH-Secreting Pituitary Adenoma surgery, Adenoma surgery, Pituitary ACTH Hypersecretion surgery, Radiosurgery methods
- Abstract
Context: Cushing disease (CD) due to adrenocorticotropic hormone-secreting pituitary tumors can be a management challenge., Objective: To better understand the outcomes of stereotactic radiosurgery (SRS) for CD and define its role in management., Design: International, multicenter, retrospective cohort analysis., Setting: Ten medical centers participating in the International Gamma Knife Research Foundation., Patients: Patients with CD with >6 months endocrine follow-up., Intervention: SRS using Gamma Knife radiosurgery., Main Outcome Measures: The primary outcome was control of hypercortisolism (defined as normalization of free urinary cortisol). Radiologic response and adverse radiation effects (AREs) were recorded., Results: In total, 278 patients met inclusion criteria, with a mean follow-up of 5.6 years (0.5 to 20.5 years). Twenty-two patients received SRS as a primary treatment of CD. Mean margin dose was 23.7 Gy. Cumulative initial control of hypercortisolism was 80% at 10 years. Mean time to cortisol normalization was 14.5 months. Recurrences occurred in 18% with initial cortisol normalization. Overall, the rate of durable control of hypercortisolism was 64% at 10 years and 68% among patients who received SRS as a primary treatment. AREs included hypopituitarism (25%) and cranial neuropathy (3%). Visual deficits were related to treatment of tumor within the suprasellar cistern (P = 0.01), whereas both visual (P < 0.0001) and nonvisual cranial neuropathy (P = 0.02) were related to prior pituitary irradiation., Conclusions: SRS for CD is well tolerated and frequently results in control of hypercortisolism. However, recurrences can occur. SRS should be considered for patients with persistent hypercortisolism after pituitary surgery and as a primary treatment in those unfit for surgery. Long-term endocrine follow-up is essential after SRS., (Copyright © 2017 Endocrine Society)
- Published
- 2017
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18. Can the gold standard be beaten? How reliable are various modifications of the Synacthen test compared to the insulin tolerance test.
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Kosak M, Duskova M, Starka L, Jandikova H, Pospisilova H, Sramkova M, Hana V, Krsek M, Springer D, and Simunkova K
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- Adult, Cosyntropin standards, Female, Humans, Hydrocortisone analysis, Hypothalamo-Hypophyseal System drug effects, Hypothalamo-Hypophyseal System metabolism, Insulin standards, Insulin Resistance physiology, Male, Pituitary-Adrenal System drug effects, Pituitary-Adrenal System metabolism, Reference Standards, Reproducibility of Results, Saliva chemistry, Saliva metabolism, Cosyntropin administration & dosage, Hydrocortisone blood, Insulin administration & dosage
- Abstract
Criteria for the evaluation of the insulin tolerance test (ITT) and Synacthen test are still a matter of debate. The objective of the study was to make a comparison of serum and salivary cortisol during four stimulation tests. Sixty four healthy volunteers underwent the ITT, the Synacthen test with 1 (LDST), 10 (MDST) and 250 (HDST) microg dose of ACTH. Maximum serum cortisol response was observed at the 90 min of the ITT (49 %), HDST (89 %) and MDST (56 %) and at the 40 min of the LDST (44 %). Results expressed as 95 % confidence intervals: 408.0-843.6 and 289.5-868.1 nmol/l in the IIT at 60 and 90 min. In the HDST and the MDST serum cortisol reached the maximum at 90 min 542.6-1245.5 and 444.2-871.3 nmol/l. Levels of salivary cortisol followed the same pattern as serum cortisol. Salivary cortisol reached the maximum response in the HDST and the MDST at 90 min and at 40 min in the LDST. We confirmed good reliability of all tests with respect to timing of response and maximum response compared to the ITT. We proved that the MDST test can provide the similar response in serum cortisol to the HDST. Measuring either salivary cortisol or ACTH levels did not provide any additional benefit then measuring serum cortisol by itself.
- Published
- 2017
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19. The possible role of mRNA expression changes of GH/IGF-1/insulin axis components in subcutaneous adipose tissue in metabolic disturbances of patients with acromegaly.
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Touskova V, Klouckova J, Durovcova V, Lacinova Z, Kavalkova P, Trachta P, Kosak M, Mraz M, Haluzikova D, Hana V, Marek J, Krsek M, and Haluzik M
- Subjects
- Adult, Case-Control Studies, Female, Human Growth Hormone blood, Humans, Insulin blood, Insulin-Like Growth Factor I metabolism, Male, Middle Aged, RNA, Messenger metabolism, Acromegaly metabolism, Class Ia Phosphatidylinositol 3-Kinase blood, Human Growth Hormone metabolism, Insulin Resistance, Insulin-Like Growth Factor Binding Protein 3 metabolism, Subcutaneous Fat metabolism
- Abstract
We explored the effect of chronically elevated circulating levels of growth hormone (GH)/insulin-like-growth-factor-1 (IGF-1) on mRNA expression of GH/IGF-1/insulin axis components and p85alpha subunit of phosphoinositide-3-kinase (p85alpha) in subcutaneous adipose tissue (SCAT) of patients with active acromegaly and compared these findings with healthy control subjects in order to find its possible relationships with insulin resistance and body composition changes. Acromegaly group had significantly decreased percentage of truncal and whole body fat and increased homeostasis model assessment-insulin resistance (HOMA-IR). In SCAT, patients with acromegaly had significantly increased IGF-1 and IGF-binding protein-3 (IGFBP-3) expression that both positively correlated with serum GH. P85alpha expression in SCAT did not differ from control group. IGF-1 and IGFBP-3 expression in SCAT were not independently associated with percentage of truncal and whole body fat or with HOMA-IR while IGFBP-3 expression in SCAT was an independent predictor of insulin receptor as well as of p85alpha expression in SCAT. Our data suggest that GH overproduction in acromegaly group increases IGF-1 and IGFBP-3 expression in SCAT while it does not affect SCAT p85alpha expression. Increased IGF-1 or IGFBP-3 in SCAT of acromegaly group do not appear to contribute to systemic differences in insulin sensitivity but may have local regulatory effects in SCAT of patients with acromegaly.
- Published
- 2016
- Full Text
- View/download PDF
20. Designing and Implementing an Assay for the Detection of Rare and Divergent NRPS and PKS Clones in European, Antarctic and Cuban Soils.
- Author
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Amos GC, Borsetto C, Laskaris P, Krsek M, Berry AE, Newsham KK, Calvo-Bado L, Pearce DA, Vallin C, and Wellington EM
- Subjects
- Actinobacteria enzymology, Actinobacteria genetics, Antarctic Regions, Base Sequence, Clone Cells, Cuba, DNA Primers metabolism, DNA, Bacterial genetics, Europe, Gene Library, Multigene Family, Phylogeny, Biological Assay methods, Peptide Synthases metabolism, Polyketide Synthases metabolism, Soil chemistry
- Abstract
The ever increasing microbial resistome means there is an urgent need for new antibiotics. Metagenomics is an underexploited tool in the field of drug discovery. In this study we aimed to produce a new updated assay for the discovery of biosynthetic gene clusters encoding bioactive secondary metabolites. PCR assays targeting the polyketide synthases (PKS) and non-ribosomal peptide synthetases (NRPS) were developed. A range of European soils were tested for their biosynthetic potential using clone libraries developed from metagenomic DNA. Results revealed a surprising number of NRPS and PKS clones with similarity to rare Actinomycetes. Many of the clones tested were phylogenetically divergent suggesting they were fragments from novel NRPS and PKS gene clusters. Soils did not appear to cluster by location but did represent NRPS and PKS clones of diverse taxonomic origin. Fosmid libraries were constructed from Cuban and Antarctic soil samples; 17 fosmids were positive for NRPS domains suggesting a hit rate of less than 1 in 10 genomes. NRPS hits had low similarities to both rare Actinobacteria and Proteobacteria; they also clustered with known antibiotic producers suggesting they may encode for pathways producing novel bioactive compounds. In conclusion we designed an assay capable of detecting divergent NRPS and PKS gene clusters from the rare biosphere; when tested on soil samples results suggest the majority of NRPS and PKS pathways and hence bioactive metabolites are yet to be discovered.
- Published
- 2015
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21. Response of cortisol metabolites in the insulin tolerance test and Synacthen tests.
- Author
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Simunkova K, Duskova M, Kosak M, Krsek M, Hana V, Hill M, Jandikova H, Pospisilova H, Sramkova M, Bifulco E, and Starka L
- Subjects
- Adult, Cortisone agonists, Female, Humans, Hydrocortisone agonists, Insulin agonists, Male, Middle Aged, Cortisone blood, Cosyntropin pharmacology, Hydrocortisone blood, Insulin blood, Insulin Resistance physiology
- Abstract
Determination of response of cortisol and its metabolites to different stimuli may be important for adrenal gland disorders. To date, only one metabolite, cortisone, has been followed in stimulation tests of the adrenal gland. We aimed to describe a response of cortisol metabolites to the standard short Synacthen test (HDST), insulin tolerance test (ITT), low dose Synacthen test (LDST) and medium dose Synacthen test (MDST). Sixty healthy subjects were investigated: 30 men and 30 women. Plasma for measurements of cortisol and its metabolites was obtained before and 30th and 60th min after Synacthen and insulin administration. The cut-off 500 nmol/l of cortisol was reached after stimulation in all of tests, the maximal stimulation level was reached in 60th min in all of the tests except for LDST. The response of cortisol and its metabolites at 30th and 60th min strongly correlated in all of the tests except for LDST. Cortisol and its metabolites increased after stimulation; in contrast, cortisone and its metabolites decreased. We showed that the response of the cortisol metabolites during the Synacthen tests and ITT well correlated, and the MDST showed similar response compared to HDST. The decrease in cortisone metabolites may correspond to the regeneration of cortisol from cortisone in response to stimulation test.
- Published
- 2015
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22. Metagenomic analysis of a southern maritime antarctic soil.
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Pearce DA, Newsham KK, Thorne MA, Calvo-Bado L, Krsek M, Laskaris P, Hodson A, and Wellington EM
- Abstract
Our current understanding of Antarctic soils is derived from direct culture on selective media, biodiversity studies based on clone library construction and analysis, quantitative PCR amplification of specific gene sequences and the application of generic microarrays for microbial community analysis. Here, we investigated the biodiversity and functional potential of a soil community at Mars Oasis on Alexander Island in the southern Maritime Antarctic, by applying 454 pyrosequencing technology to a metagenomic library constructed from soil genomic DNA. The results suggest that the commonly cited range of phylotypes used in clone library construction and analysis of 78-730 OTUs (de-replicated to 30-140) provides low coverage of the major groups present (∼5%). The vast majority of functional genes (>77%) were for structure, carbohydrate metabolism, and DNA/RNA processing and modification. This study suggests that prokaryotic diversity in Antarctic terrestrial environments appears to be limited at the generic level, with Proteobacteria, Actinobacteria being common. Cyanobacteria were surprisingly under-represented at 3.4% of sequences, although ∼1% of the genes identified were involved in CO(2) fixation. At the sequence level there appeared to be much greater heterogeneity, and this might be due to high divergence within the relatively restricted lineages which have successfully colonized Antarctic terrestrial environments.
- Published
- 2012
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23. Plasma concentrations of fibroblast growth factors 21 and 19 in patients with Cushing's syndrome.
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Ďurovcová V, Marek J, Hána V, Matoulek M, Zikán V, Haluzíková D, Kaválková P, Lacinová Z, Krsek M, and Haluzík M
- Subjects
- Adiposity, Adult, Biomarkers blood, Body Mass Index, Case-Control Studies, Cushing Syndrome physiopathology, Enzyme-Linked Immunosorbent Assay, Female, Humans, Hydrocortisone blood, Male, Middle Aged, Obesity physiopathology, Waist Circumference, Cushing Syndrome blood, Fibroblast Growth Factors blood, Obesity blood
- Abstract
The objective of this study was to measure plasma fibroblast growth factor 21 and 19 (FGF21 and FGF19) levels in patients with Cushing's syndrome (CS) and to compare it with those of lean control subjects (C) and patients with obesity (OB). Fourteen untreated patients with CS, 19 patients with OB and 36 controls were included in the study. Plasma FGF21 and FGF19 levels were measured by ELISA kits, other hormonal and biochemical parameters were measured by standard laboratory methods. Plasma FGF19 did not significantly differ among the studied groups. Plasma FGF21 levels were significantly higher in both CS and OB groups relative to C group but they did not differ between CS and OB groups. In a combined population of all three groups FGF21 levels positively correlated with BMI, waist circumference and percentage of total and truncal fat mass. Less prominent inverse relationship with these parameters was found for FGF19. Neither FGF21 nor FGF19 were significantly related to cortisol concentrations. Increased FGF21 concentrations in both patients with CS and OB relative to lean subjects suggest that excessive body fat and/or related metabolic abnormalities rather than direct effects of cortisol are responsible. In contrast neither obesity nor hypercortisolism significantly affected FGF19 concentrations.
- Published
- 2010
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24. Impaired microvascular reactivity and endothelial function in patients with Cushing's syndrome: influence of arterial hypertension.
- Author
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Prázný M, Ježková J, Horová E, Lazárová V, Hána V, Kvasnicka J, Pecen L, Marek J, Skrha J, and Krsek M
- Subjects
- Adult, Analysis of Variance, Biomarkers metabolism, Blood Coagulation physiology, Body Mass Index, Case-Control Studies, Cushing Syndrome complications, Cushing Syndrome physiopathology, Female, Fibrinolysis physiology, Humans, Hydrocortisone blood, Hyperemia complications, Hyperemia physiopathology, Hypertension complications, Hypertension physiopathology, Insulin Resistance physiology, Intercellular Adhesion Molecule-1 metabolism, Laser-Doppler Flowmetry, Male, Matched-Pair Analysis, Middle Aged, Oxidative Stress physiology, Reference Values, Statistics, Nonparametric, Cushing Syndrome blood, Endothelium, Vascular physiopathology, Hyperemia blood, Hypertension blood, Microcirculation physiopathology
- Abstract
The aim of the study was to evaluate skin microvascular reactivity (MVR) and possible influencing factors (fibrinolysis, oxidative stress, and endothelial function) in patients with Cushing's syndrome. Twenty-nine patients with active Cushing's syndrome (ten of them also examined after a successful operation) and 16 control subjects were studied. Skin MVR was measured by laser Doppler flowmetry during post-occlusive (PORH) and thermal hyperemia (TH). Malondialdehyde and Cu,Zn-superoxide dismutase were used as markers of oxidative stress. Fibrinolysis was estimated by tissue plasminogen activator (tPA) and its inhibitor (PAI-1). N-acetyl-beta-glucosaminidase, E-selectin, P-selectin, and ICAM-1 were used as markers of endothelial function. Oxidative stress and endothelial dysfunction was present in patients with hypercortisolism, however, increased concentration of ICAM-1 was also found in patients after the operation as compared to controls (290.8+/-74.2 vs. 210.9+/-56.3 ng.ml(-1), p<0.05). Maximal perfusion was significantly lower in patients with arterial hypertension during PORH and TH (36.3+/-13.0 vs. 63.3+/-32.4 PU, p<0.01, and 90.4+/-36.6 vs. 159.2+/-95.3 PU, p<0.05, respectively) and similarly the velocity of perfusion increase during PORH and TH was lower (3.2+/-1.5 vs. 5.2+/-3.4 PU.s(-1), p<0.05, and 0.95+/-0.6 vs. 1.8+/-1.1 PU.s(-1), p<0.05, respectively). The most pronounced impairment of microvascular reactivity was present in patients with combination of arterial hypertension and diabetes mellitus.
- Published
- 2008
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25. Plasma levels of total and active ghrelin in acromegaly and growth hormone deficiency.
- Author
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Jarkovská Z, Rosická M, Marek J, Hána V, Weiss V, Justová V, Lacinová Z, Haluzík M, and Krsek M
- Subjects
- Adult, Anthropometry, Case-Control Studies, Female, Ghrelin, Hormones blood, Humans, Male, Middle Aged, Nutritional Status, Somatomedins metabolism, Acromegaly blood, Human Growth Hormone deficiency, Peptide Hormones blood
- Abstract
Ghrelin is an endogenous growth hormone (GH) secretagogue recently isolated from the stomach. Although it possesses a strong GH releasing activity in vitro and in vivo, its physiological significance in endogenous GH secretion remains unclear. The aim of this study was to characterize plasma ghrelin levels in acromegaly and growth hormone deficiency (GHD). We investigated plasma total and active ghrelin in 21 patients with acromegaly, 9 patients with GHD and 24 age-, sex- and BMI-matched controls. In all subjects, we further assessed the concentrations of leptin, soluble leptin receptor, insulin, IGF-I, free IGF-I and IGFBP-1, 2, 3 and 6. Patients with acromegaly and GHD as well as control subjects showed similar levels of total ghrelin (controls 2.004+/-0.18 ng/ml, acromegalics 1.755+/-0.16 ng/ml, p=0.31, GHD patients 1.704+/-0.17 ng/ml, p=0.35) and active ghrelin (controls 0.057+/-0.01 ng/ml, acromegalics 0.047+/-0.01 ng/ml, p=0.29, GHD patients 0.062+/-0.01 ng/ml, p=0.73). In acromegalic patients plasma total ghrelin values correlated negatively with IGF-I (p<0.05), in GHD patients active ghrelin correlated with IGF-I positively (p<0.05). In the control group, total ghrelin correlated positively with IGFBP-2 (p<0.05) and negatively with active ghrelin (p=0.05), BMI (p<0.05), WHR (p<0.05), insulin (p=0.01) and IGF-I (p=0.05). Plasma active ghrelin correlated positively with IGFBP-3 (p=0.005) but negatively with total ghrelin and free IGF-I (p=0.01). In conclusion, all groups of the tested subjects showed similar plasma levels of total and active ghrelin. In acromegaly and growth hormone deficiency plasma ghrelin does not seem to be significantly affected by changes in GH secretion.
- Published
- 2006
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26. Increased lipolysis of subcutaneous abdominal adipose tissue and altered noradrenergic activity in patients with Cushing's syndrome: an in-vivo microdialysis study.
- Author
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Krsek M, Rosická M, Nedvídková J, Kvasnicková H, Hána V, Marek J, Haluzík M, Lai EW, and Pacák K
- Subjects
- Abdomen, Adult, Cushing Syndrome physiopathology, Dihydroxyphenylalanine blood, Epinephrine blood, Female, Humans, Hydrocortisone blood, Male, Methoxyhydroxyphenylglycol analogs & derivatives, Methoxyhydroxyphenylglycol blood, Microdialysis, Middle Aged, Subcutaneous Fat innervation, Cushing Syndrome metabolism, Lipolysis physiology, Norepinephrine blood, Subcutaneous Fat metabolism, Sympathetic Nervous System physiology
- Abstract
Cushing's syndrome is associated with typical central redistribution of adipose tissue. The aim of the study was to assess lipolysis and catecholamines and their metabolites in subcutaneous abdominal adipose tissue using an in-vivo microdialysis technique. Nine patients with Cushing's syndrome and nine age-, gender- and body mass index (BMI)-matched control subjects were included in the study. Local glycerol concentrations were significantly increased in subcutaneous adipose tissue of patients with Cushing's syndrome (p<0.001). Plasma noradrenaline, dihydroxyphenylglycol and dihydroxyphenylalanine were decreased in patients with Cushing's syndrome (p<0.02, p<0.05, and p<0.02, respectively). Adrenaline, noradrenaline, dihydroxyphenylglycol and dihydroxyphenylalanine concentrations in subcutaneous abdominal adipose were non-significantly higher in patients with Cushing's syndrome. In conclusion, we showed that lipolysis in subcutaneous adipose tissue of patients with Cushing's syndrome is significantly increased as compared to healthy subjects. This finding together with non-significantly increased local catecholamine concentrations in these patients suggests a possible link between increased lipolysis and catecholaminergic activity in subcutaneous adipose tissue.
- Published
- 2006
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27. Angiogenic factors are elevated in overweight and obese individuals.
- Author
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Silha JV, Krsek M, Sucharda P, and Murphy LJ
- Subjects
- Adiponectin blood, Adult, Analysis of Variance, Angiopoietin-2 blood, Female, Hepatocyte Growth Factor blood, Humans, Insulin Resistance, Leptin blood, Linear Models, Male, Middle Aged, Overweight, Ribonuclease, Pancreatic blood, Sex Characteristics, Vascular Endothelial Growth Factor A blood, Vascular Endothelial Growth Factor C blood, Vascular Endothelial Growth Factor D blood, Vascular Endothelial Growth Factor Receptor-2 blood, Angiogenic Proteins blood, Endostatins blood, Obesity blood
- Abstract
Background: Adipose tissue produces both vascular growth factors and inhibitors. Since obesity is associated with expansion of the capillary bed in regional adipose depots the balance between these factors may favor angiogenesis., Objective: To investigate the relationship between body mass index and serum concentrations of vascular growth factors in human subjects., Methods: Vascular endothelial growth factor (VEGF), VEGF-C, VEGF-D, soluble VEGF receptor-2 (sVEGFr2), hepatocyte growth factor (HGF), angiopoietin-2, angiogenin and endostatin concentrations were measured in serum collected from 58 lean (24 males, 34 female, mean BMI, 22.2+/-0.3) and 42 overweight and obese (16 males and 26 females, mean BMI, 33.5+/-1.2) subjects after an overnight fast., Results: Sexual dimorphism was apparent in the serum concentrations of VEGF-C, VEFG-D and angiopoietin-2 with significantly higher levels in female compared to male subject. VEGF, VEGF-C, VEGF-D, soluble VEGF receptor-2, angiopoietin-2, angiogenin and endostatin but not HGF were significantly elevated in overweight and obese subjects. Positive correlations between BMI and the serum concentrations of VEGF-C, VEGF-D, sVEGF-R2, angiopoietin-2, angiogenin and endostatin were observed even after adjustment for gender and age., Conclusions: Increased levels of vascular growth factors as well as the angiogenesis inhibitor endostatin are present in overweight and obese subjects and may contribute to previously documented increased risk of metastatic disease in obese subjects with cancer.
- Published
- 2005
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28. Soil invertebrates disrupt carbon flow through fungal networks.
- Author
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Johnson D, Krsek M, Wellington EM, Stott AW, Cole L, Bardgett RD, Read DJ, and Leake JR
- Subjects
- Animals, Carbon Isotopes, Environment, Fatty Acids analysis, Feeding Behavior, Food Chain, Mycorrhizae metabolism, Oxygen Consumption, Phospholipids analysis, Plant Roots microbiology, Scotland, Symbiosis, Arthropods physiology, Carbon Dioxide metabolism, Ecosystem, Mycorrhizae physiology, Soil analysis, Soil Microbiology
- Abstract
Annual carbon flux through soil respiration is ten times greater than fossil fuel combustion, but its component parts are poorly understood because they are the product of complex multitrophic interactions between soil organisms. A major component of carbon flux from plants to soil occurs through networks of symbiotic arbuscular mycorrhizal fungi. Here, using 13CO2 pulse labeling, we show that natural densities of the numerically dominant fungal feeding invertebrate Protaphorura armata (order Collembola) reduces 13C enrichment of mycorrhizosphere respiration by 32%. Our findings emphasize the importance of multitrophic interactions in regulating respiration of recent plant photosynthate from soil.
- Published
- 2005
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- View/download PDF
29. Plasma ghrelin levels in patients with end-stage renal disease.
- Author
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Jarkovská Z, Rosická M, Krsek M, Sulková S, Haluzík M, Justová V, Lacinová Z, and Marek J
- Subjects
- Aged, Body Composition physiology, Creatinine blood, Female, Ghrelin, Human Growth Hormone metabolism, Humans, Insulin metabolism, Insulin-Like Growth Factor Binding Protein 1 metabolism, Insulin-Like Growth Factor Binding Protein 3 metabolism, Insulin-Like Growth Factor Binding Protein 6 metabolism, Insulin-Like Growth Factor I metabolism, Leptin blood, Male, Middle Aged, Receptors, Cell Surface metabolism, Receptors, Leptin, Renal Dialysis, Kidney Failure, Chronic blood, Peptide Hormones blood
- Abstract
Ghrelin is an acylated peptide stimulating secretion of the growth hormone (GH). It was originally isolated from the rat stomach as an endogenous ligand for the growth hormone secretagogue receptor. Although being predominantly produced by endocrine cells of the gastric fundus, its secretion has been found in various tissues including the kidney. To study the influence of renal failure on plasma ghrelin levels we examined 16 patients with end-stage renal disease (ESRD) receiving hemodialysis (8 men and 8 women) and 19 controls (10 men and 9 women). Both groups were comparable in age and BMI. In all subjects we assessed plasma levels of ghrelin, leptin, soluble leptin receptor, insulin, IGF-I, IGFBP-1, IGFBP-3 and IGFBP-6. Ghrelin levels were significantly higher in the group of dialyzed patients (4.49+/-0.74 vs. 1.79+/-0.15 ng/ml; p<0.001). These patients had significantly higher levels of GH, IGFBP-1, IGFBP-6, leptin and percentage of body fat (p<0.05). In the group of patients with ESRD plasma ghrelin levels positively correlated with IGFBP-1 (p<0.01). In the control group, ghrelin positively correlated with GH concentrations (p<0.01) and negatively correlated with the levels of insulin and creatinine (p<0.05). In conclusion, patients with ESRD have higher ghrelin concentrations, which might be caused by a decreased excretion/metabolism of ghrelin in the kidney during renal failure.
- Published
- 2005
30. Endocrine and metabolic activities of a recently isolated peptide hormone ghrelin, an endogenous ligand of the growth hormone secretagogue receptor.
- Author
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Jarkovska Z, Krsek M, Rosicka M, and Marek J
- Subjects
- Animals, Ghrelin, Growth Hormone-Releasing Hormone agonists, Humans, Ligands, Peptide Hormones chemistry, Peptide Hormones isolation & purification, Receptors, Ghrelin, Peptide Hormones physiology, Receptors, G-Protein-Coupled metabolism
- Abstract
Ghrelin is a member of the group of growth hormone secretagogues (GHSs). It is a peptide hormone, recently isolated from stomach as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R). Ghrelin is mostly produced by the stomach, although its production has been proved in various tissues. It is a potent releaser of growth hormone (GH) from anterior pituitary cells, but it also stimulates the release of other hypophyseal hormones. Ghrelin stimulates food intake and induces metabolic changes leading to an increase in body weight and body fat mass. This effect seems to be independent of GH action and needs an intact NPY/AGRP (neuropeptide Y/agouti-related protein) system. Plasma ghrelin levels are decreased in obesity, elevated in cachexia and show a diurnal rhythm. Its preprandial elevation suggests, that it might be a signal for meal initiation. Ghrelin further stimulates the release of gastric acid and gastric motility and affects pancreatic functions. It has vasodilatatory, cardioprotective and antiproliferative effects. This article is focused on ghrelin's endocrine and metabolic functions.
- Published
- 2004
31. Serum ghrelin levels in obese patients: the relationship to serum leptin levels and soluble leptin receptors levels.
- Author
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Rosická M, Krsek M, Matoulek M, Jarkovská Z, Marek J, Justová V, and Lacinová Z
- Subjects
- Adult, Body Mass Index, Female, Ghrelin, Humans, Male, Middle Aged, Receptors, Leptin, Leptin blood, Obesity blood, Peptide Hormones blood, Receptors, Cell Surface blood
- Abstract
Ghrelin is a new endogenous ligand for the growth hormone secretagogue receptor. It activates the release of growth hormone from the pituitary and it also participates in the regulation of energy homeostasis. The aim of the study was to characterize changes in serum ghrelin levels in obese subjects and their relationship to the serum levels of leptin and soluble leptin receptor. Eight obese patients (6 women and 2 men) with body mass index (BMI) 40.3+/-13.4 kg.m(-2) and eight healthy controls (5 women and 3 men) with BMI 22.7+/-1.3 kg.m(-2) were examined. The ghrelin serum levels (165.0+/-58.1 vs. 343.37+/-81.96; p<0.001) and soluble leptin receptor serum levels (7.25+/-3.44 vs. 21.80+/-4.99; p<0.0001) were significantly lower in obese patients. The leptin serum levels (23.45+/-12.90 vs. 6.41+/-2.96; p<0.005) were significantly higher compared to the lean subject group. In both measured groups the levels of serum leptin significantly positively correlated with BMI. We proved a significantly lower serum ghrelin levels in the group of obese patients in comparison with the control group.
- Published
- 2003
32. Molecular analysis of a bacterial chitinolytic community in an upland pasture.
- Author
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Metcalfe AC, Krsek M, Gooday GW, Prosser JI, and Wellington EM
- Subjects
- Actinomycetales classification, Actinomycetales genetics, Actinomycetales metabolism, Bacteria classification, Bacteria genetics, Bacteria isolation & purification, Chitinases metabolism, DNA, Ribosomal analysis, DNA, Ribosomal genetics, Microscopy, Electron, Scanning, Phylogeny, Actinomycetales isolation & purification, Chitin metabolism, Ecosystem, Soil Microbiology
- Abstract
The effects of agricultural-improvement treatments on the chitinolytic activity and diversity of a microbial community were investigated within an upland pasture. The treatments of interest were lime and treated sewage sludge, both commonly applied to pasture land to improve fertility. Burial of chitin-containing litter bags at the field site resulted in enrichment of bacteria according to 16S rRNA fingerprinting. Chitinolytic-activity measurements showed that the highest activity occurred in those bags recovered from sludge-amended plots, which correlated well with increased counts of actinobacteria in samples from these chitin bags. Our findings suggest that sewage sludge increases the fertility of the soil in terms of chitinase activity. Ten clone libraries were constructed from family 18 subgroup A chitinases, PCR amplified from litter bags buried in soil in July 2000 or in September 2000, in a separate study. Analysis of these libraries by restriction fragment length polymorphism and sequencing showed that they were dominated by actinobacterium-like chitinase sequences. This suggests that actinobacteria have an important chitinolytic function in this soil ecosystem. Our findings showed that sludge application increased chitinolytic activity but decreased the diversity of chitinases present.
- Published
- 2002
- Full Text
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33. Ghrelin -- a new endogenous growth hormone secretagogue.
- Author
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Rosická M, Krsek M, Jarkovská Z, Marek J, and Schreiber V
- Subjects
- Animals, Ghrelin, Humans, Human Growth Hormone metabolism, Neurosecretory Systems physiology, Peptide Hormones physiology
- Abstract
Ghrelin is a new endogenous peptide, discovered in 1999 by Kojima et al., as the result of a search for an endogenous ligand for an orphan receptor of known structure and function. Ghrelin is composed of 28 amino acids and is produced mostly by cells of the stomach, hypothalamus, and hypophysis, but it has also been detected in other tissues. Its discovery is related to the development of a new hypothesis regarding the regulation of growth hormone secretion. It is an antagonist of somatostatin. Ghrelin activates the release of growth hormone from the somatotrophic cells of the hypophysis. It participates in the regulation of energy homeostasis, increases food intake, decreases energy output and exerts a lipogenetic effect. Its metabolic effects do not depend on the GH/IGF-I system, but are mediated by the NPY/Y1 and AGRP receptor system. Ghrelin influences the secretion and motility of the gastrointestinal tract, especially the stomach. The presence of ghrelin and its receptors has also been demonstrated in many other tissues. Its function in these tissues has not yet been studied, thus providing many possibilities for further research.
- Published
- 2002
34. The relationship between the IGF-I system and its binding proteins and microvascular reactivity in Type 1 diabetes mellitus.
- Author
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Krsek M, Prázný M, Skrha J, Justová V, Lacinová Z, and Haas T
- Subjects
- Female, Humans, Laser-Doppler Flowmetry, Male, Microcirculation, Middle Aged, Reference Values, Blood Circulation, Diabetes Mellitus, Type 1 physiopathology, Insulin-Like Growth Factor Binding Proteins metabolism, Insulin-Like Growth Factor I metabolism
- Abstract
The system of IGF-I and its binding proteins may be involved in the pathogenesis of vascular damage in Type 1 diabetes. The aim of this study was to analyze the relationship between this system and the microvascular reactivity in Type 1 diabetes as measured by laser-Doppler flowmetry. Twenty-two Type 1 diabetic patients (13 women and 9 men) with microangiopathy and fifteen healthy subjects (8 women and 7 men) were examined clinically, underwent laser-Doppler flowmetry and intima-media thickness measurements. Fasting serum levels of IGF-I, free IGF-I, IGFBPs and lipids were examined. The microvascular reactivity was impaired in Type 1 diabetic patients. Maximal perfusion during post-occlusive reactive hyperemia (PORHmax) and during thermal hyperemia (THmax) was significantly decreased in Type 1 diabetes (p<0.01). Percentage perfusion increase in both tests (PORH and TH) was lower in Type 1 diabetes mellitus (p<0.01) and the reaction after heating was slower in diabetic patients (THmax) (p<0.01). We did not find any significant dependence of microvascular reactivity on the parameters of IGF-I or its binding proteins. We conclude that the microvascular reactivity is impaired in Type 1 diabetes mellitus, but this impairment is not clearly dependent on the activity of the IGF-I system. It is probably only a complementary pathogenic factor.
- Published
- 2002
35. Analysis of actinomycete communities by specific amplification of genes encoding 16S rRNA and gel-electrophoretic separation in denaturing gradients.
- Author
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Heuer H, Krsek M, Baker P, Smalla K, and Wellington EM
- Subjects
- Bacteria genetics, DNA Primers genetics, Electrophoresis, Polyacrylamide Gel methods, Polymerase Chain Reaction methods, Sensitivity and Specificity, Sequence Alignment, Soil Microbiology, Actinomycetales genetics, Actinomycetales isolation & purification, DNA, Bacterial analysis, RNA, Ribosomal, 16S genetics
- Abstract
A group-specific primer, F243 (positions 226 to 243, Escherichia coli numbering), was developed by comparison of sequences of genes encoding 16S rRNA (16S rDNA) for the detection of actinomycetes in the environment with PCR and temperature or denaturing gradient gel electrophoresis (TGGE or DGGE, respectively). The specificity of the forward primer in combination with different reverse ones was tested with genomic DNA from a variety of bacterial strains. Most actinomycetes investigated could be separated by TGGE and DGGE, with both techniques giving similar results. Two strategies were employed to study natural microbial communities. First, we used the selective amplification of actinomycete sequences (E. coli positions 226 to 528) for direct analysis of the products in denaturing gradients. Second, a nested PCR providing actinomycete-specific fragments (E. coli positions 226 to 1401) was used which served as template for a PCR when conserved primers were used. The products (E. coli positions 968 to 1401) of this indirect approach were then separated by use of gradient gels. Both approaches allowed detection of actinomycete communities in soil. The second strategy allowed the estimation of the relative abundance of actinomycetes within the bacterial community. Mixtures of PCR-derived 16S rDNA fragments were used as model communities consisting of five actinomycetes and five other bacterial species. Actinomycete products were obtained over a 100-fold dilution range of the actinomycete DNA in the model community by specific PCR; detection of the diluted actinomycete DNA was not possible when conserved primers were used. The methods tested for detection were applied to monitor actinomycete community changes in potato rhizosphere and to investigate actinomycete diversity in different soils.
- Published
- 1997
- Full Text
- View/download PDF
36. Impaired glucose homeostasis in insulin-like growth factor binding protein-1 transgenic mice.
- Author
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Rajkumar K, Krsek M, Dheen ST, and Murphy LJ
- Subjects
- Animals, Blood Glucose analysis, Deoxyglucose metabolism, Insulin metabolism, Insulin pharmacology, Insulin Secretion, Insulin-Like Growth Factor Binding Protein 1 analysis, Insulin-Like Growth Factor Binding Protein 1 genetics, Insulin-Like Growth Factor I pharmacology, Islets of Langerhans metabolism, Male, Mice, Mice, Transgenic, Glucose metabolism, Homeostasis, Insulin-Like Growth Factor Binding Protein 1 physiology
- Abstract
Transgenic mice that overexpressed IGFBP-1 are hyperinsulinemic in the first week of life and gradually develop fasting hyperglycemia. In adult transgenic mice, the hypoglycemic response to IGF-I but not insulin or des (1-3) IGF-I was attenuated (P < 0.05) compared with wild-type mice. Furthermore, in isolated adipocytes from transgenic mice, the stimulatory effect of IGF-I but not insulin on 2-deoxy-[3H]-glucose uptake was reduced (P < 0.02). In contrast, in isolated soleus muscle, the effects of both IGF-I and insulin on 2-deoxy-3H-glucose uptake and on [3H]-glucose incorporation into glycogen were significantly reduced compared to wild-type mice. The decline in specific activity of the 2-deoxy-3H-glucose, a measure of glucose appearance in the circulation, was more marked in transgenic animals (P < 0.05). In addition, tissue uptake of glucose was significantly higher in diaphragm, heart, intestine, liver, soleus muscle, and adipose tissue from fasting transgenic mice. Plasma concentrations of alanine, lysine, and methionine were also elevated in transgenic mice. These data suggest that overexpression of IGFBP-1 attenuates the hypoglycemic effect of endogenous IGF-I, which is initially compensated for by enhanced pancreatic insulin production. However, in adult mice pancreatic insulin content is reduced, insulin resistance is demonstrable in skeletal muscle and fasting hyperglycemia develops.
- Published
- 1996
- Full Text
- View/download PDF
37. Impaired estrogen action in the uterus of insulin-like growth factor binding protein-1 transgenic mice.
- Author
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Rajkumar K, Dheen T, Krsek M, and Murphy LJ
- Subjects
- Animals, Base Sequence, DNA biosynthesis, Epidermal Growth Factor pharmacology, Female, Humans, Insulin-Like Growth Factor I pharmacology, Mice, Molecular Probes genetics, Molecular Sequence Data, Polymerase Chain Reaction methods, Recombinant Proteins, Transcription, Genetic, Uterus chemistry, Uterus metabolism, Estradiol pharmacology, Insulin-Like Growth Factor Binding Protein 1 genetics, Mice, Transgenic genetics, Uterus drug effects
- Abstract
Insulin-like growth factor-I (IGF-I) has been implicated as autocrine/paracrine mediator of estrogen action in the rodent uterus. Here, we examined the effects of 17-beta estradiol (E2), epidermal growth factor (EGF), and IGF-I on DNA synthesis in the uterus of ovariectomized (ovex) transgenic mice (Tg), which overexpress rat insulin-like growth factor binding protein-1 (IGFBP-1). Litter size was significantly reduced in Tg mice compared with wild-type mice. Immunohistochemical studies localized the expression of the transgene to the luminal and glandular epithelium. In addition, rat IGFBP-1 immunoreactivity was present in luminal secretions. E2-induced uterine DNA synthesis as measured by methyl-3H thymidine incorporation, was significantly reduced in ovex Tg mice; 4.77 +/- 0.59 and 4.97 +/- 0.53 for Tg strains 57C and 277A, respectively, compared with 8.65 +/- 0.73 fmol/microgram of DNA for Wt mice. Similarly, uterine weight after three daily injections of E2 was reduced in Tg mice compared with Wt mice; 2.85 +/- 0.39 vs. 4.23 +/- 0.26 mg/g BW, P < 0.01. Semiquantitative RT-PCR assays were used to demonstrate changes in uterine IGF-I messenger RNA (mRNA) and EGF mRNA abundance after administration of E2. An approximately 3-fold increase in IGF-I mRNA abundance was seen 6 h after E2 in both Tg and Wt mice. Over the same time course, little change was seen in EGF mRNA levels, which were similar in Tg and Wt mice. After 3 days of E2 treatment, an increase in EGF mRNA was apparent in Wt mice but not in Tg mice. The uterine DNA response to both IGF-I and EGF was significantly attenuated in Tg mice compared with Wt mice. The data reported here together with previous reports of E2 regulation of IGF-I and IGFBP-1 expression in uterus support the hypothesis that the IGF-I is a mediator of estrogen action in the uterus. In addition attenuation of the EGF response in the uterine tissue of Tg mice suggests that this response is also mediated, in part, by IGF-I.
- Published
- 1996
- Full Text
- View/download PDF
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