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Distal contractile integral (DCI) is influenced by factors other than esophageal smooth muscle contractility, such as intrabolus pressure and vascular and respiratory movements’ artifacts. We aimed to determine the size of the contribution of pressures generated by vascular compression on the esophagus to the DCI measured in HRM recordings in symptomatic patients. HRM manometry recordings obtained from 383 subjects referred to the GI motility laboratory at a tertiary center (2012–2016) were evaluated by visual inspection for evidence of strong vascular compression (SVC) of the esophagus. Clinical, demographic, manometric, and serologic data for Chagas disease were obtained. Subjects were classified, respectively, as asymptomatics (ASYM) or symptomatics (SYMP). DCI and SVC-DCI were measured, and the SVC-DCI/DCI ratio was expressed as a percentage and the difference between DCI and SVC-DCI (neat-DCI) was calculated. DCI, SVC-DCI, SVC-DCI/DCI % and neat-DCI from SYMP and ASYM were compared. SVC was conspicuous in 42 of 383 subjects (11%). In 33 subjects, SVC was detected only in supine position. SVC was localized in middle esophagus in 21 subjects (50%), in distal esophagus in 12 subjects (29%) and in both regions in 9 subjects (21%). In 9 subjects, SVC vanished from the swallowing window analysis (21%). SVC is a common finding in esophageal HRM study, particularly in the supine position. Occasionally, its contribution to DCI value is sufficiently great to masquerade esophageal hypocontractility. Different manometric protocols may be required in patients with SVC.

Background: Inflammatory bowel disease (IBD) is associated with delay in gastric emptying, increase in ghrelin, and decrease in leptin. The aim was to investigate the correlation between gastroduodenal (GD) symptoms, gastric emptying, and serum levels of active ghrelin and leptin in IBD. Twenty-seven IBD patients and 26 healthy volunteers were asked to complete the Porto Alegre Dyspeptic Symptoms Questionnaire. A gastric emptying test for solids was performed using a C13 octanoic acid breath test. During this test, serum samples were collected for measuring active ghrelin and leptin concentrations by radioimmunoassay. Summary: Patients with IBD demonstrated delayed gastric emptying compared with healthy volunteers. In patients with GD symptoms, the delay in gastric emptying was more pronounced, and there were significant correlations of satiety and vomiting with gastric emptying. Basal leptin, but not active ghrelin, increased in patients with GD symptoms compared with patients without these symptoms. There were negative correlations between basal active ghrelin with total Porto Alegre score and epigastric pain in IBD patients with GD symptoms. Key Messages: In IBD, satiety and vomiting were associated with delay in gastric emptying. Conversely, epigastric pain had a negative correlation with active ghrelin. Our results suggest that different pathophysiological mechanisms contribute to GD symptoms in IBD.

Made available in DSpace on 2021-06-25T11:15:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Background: Gastroparesis is a chronic stomach disorder and effective treatment is the aim of different strategies. Alternative therapies consist of an electrical stimulation of the stomach to evoke a response in the gastric activity. We present the development and in vivo application of an electromagnet system to induce a mechanical stimulus in the stomach aiming for gastric contractile responses. Methods: The electromagnet system consisted of an implantable magnet and an external drive coil. We implanted the magnet at the greater curvature of the gastric body in rats. We applied an alternating current to the drive coils, inducing mechanical stimulation of the gastric wall. We measured the gastric contraction activity and gastric electrical activity in response to the stimulus using AC biosusceptometry and electrogastrography. Moreover, we used the phenol red to evaluate the stimulus effects on gastrointestinal transit. Key Results: The stimulus increased the spectral intensity and signal-to-noise ratio significantly of gastric contraction activity and gastric electrical activity. Furthermore, we found a lower phenol red retention in the stomach in rats without stimulus. No significant differences were found in frequency and root mean square amplitude. Conclusions & Inferences: We developed a new simple electromagnet system that evoked a contraction and gastric electrical response using a mechanical stimulus and decreased gastric emptying time. The system is an accessible tool and may contribute to gastroparesis studies in animals. Departamento de Biofísica e Farmacologia Laboratório de Biomagnetismo UNESP/São Paulo State University Faculdade de Medicina de Ribeirão Preto USP/University of São Paulo Instituto de Física USP/University of São Paulo Departamento de Biofísica e Farmacologia Laboratório de Biomagnetismo UNESP/São Paulo State University

Vigorous exercise can induce gastrointestinal disorders such decreased gastric emptying pace, while low-intensity exercise can accelerate gastric motility. However, the mechanisms of these effects are still unknown. We investigated the possible neurohumoral mechanisms involved in these phenomena. In sedentary (Sed) and acute exercise (Ex) groups of rats, we assessed the activation of c-Fos in NTS and DVMN and the plasma levels of CCK and OXT. Separate groups received pretreatment with the oxytocin antagonist atosiban (AT), the cholecystokinin antagonist devazepide (DVZ), or the TRPV1 receptor inhibitor capsazepine (CAPZ). AT, DVZ and CAPZ treatments prevented (p

Made available in DSpace on 2022-04-28T19:43:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-08-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Pharmacomagnetography involves the simultaneous assessment of solid dosage forms (SDFs) in the human gastrointestinal (GI) tract and the drug plasmatic concentration, using a biomagnetic technique and pharmacokinetics analysis. This multi-instrumental approach helps the evaluation, as GI variables can interfere with the drug delivery processes. This study aimed to employ pharmacomagnetography to evaluate the influence of omeprazole on the drug release and absorption of metronidazole administered orally in magnetic-coated tablets. Magnetic-coated tablets, coated with Eudragit® E-100 (E100) and containing 100 mg of metronidazole, were produced. For the in vivo experiments, 12 volunteers participated in the two phases of the study (placebo and omeprazole) on different days to assess the bioavailability of metronidazole. The results indicated a shift as the pH of the solution increased and a delay in the dissolution of metronidazole, showing that the pH increase interferes with the release processes of tablets coated with E100. Our study reinforced the advantages of pharmacomagnetography as a tool to perform a multi-instrumental correlation analysis of the disintegration process and the bioavailability of drugs. Department of Biophysics and Pharmacology Institute of Biosciences São Paulo State University—UNESP Center of Integrative Sciences Alagoas State University of Health Sciences—UNCISAL School of Medicine of Ribeirão Preto University of São Paulo Department of Biophysics and Pharmacology Institute of Biosciences São Paulo State University—UNESP FAPESP: 2015/1492.3-9 CNPq: 312074/2018-9

Chagas disease, formerly confined to the Latin-American sub-continent, is now diagnosed in vast numbers of T. cruzi chronically infected individuals living in the United States, Canada, virtually all European countries, Asia, and Oceania, because of recent population migratory and globalization patterns.

Objective: Saliva is the most important biological factor to protect against erosive tooth wear (ETW). Gastroesophageal reflux disease (GERD) patients have an increased risk of ETW due to the frequent presence of intrinsic acids in the oral cavity. Remarkably, not all GERD patients suffer from ETW, which might be due to differences in the composition of the saliva. Methods: This study compared the proteomic profile of saliva in patients (1) with GERD and ETW (basic erosive wear examination, BEWE, score ≥9; GE group) and (2) with GERD without ETW (BEWE = 0; GNE group) using shotgun label-free quantitative proteomic analysis nLC-ESI-MS/MS. The ability of hemoglobin (Hb) to protect against initial enamel erosion caused by a daily 10-s immersion of enamel specimens in 0.01 M HCl (pH 2.3) for 3 days was evaluated in vitro for proof of concept. Surface hardness change was used as response variable. Results: The differential expression of Hb subunits was significantly increased in the GNE group versus the GE group, in particular the Hb α-subunit that showed a >22-fold increase. Expressions of serum albumin (4.5-fold) and isoforms of cytoskeletal keratin type II (>3-fold) were also increased in the GNE group. Proteinase inhibitors, such as α1-antitrypsin and α2-macroglobulin, were only identified in the GNE group. In vitro, Hb (1.0 and 4.0 mg/mL) significantly reduced initial enamel erosion compared to a negative control after 3 days. Conclusions: Our results indicate that many proteins, with special emphasis on Hb, may be involved in the resistance of GERD patients to the occurrence of ETW. These proteins may be candidates for inclusion in dental products to protect against ETW.

BACKGROUND Reduced vagal activity is often present in obese adolescents. Simple and practical strategies for the assessment of isolate parasympathetic outflow in this population are therefore useful. OBJECTIVES To compare the methods derived from heart rate variability (HRV) analysis at rest and 4 s exercise testing (T4S) for the assessment of cardiac parasympathetic modulation in adolescents classified as obese (OB) or with normal weight (NW). Additionally, associations between total and trunk fat versus autonomic modulation determined by the two methods were calculated. APPROACH A cross-sectional study was conducted with 50 adolescents (26 OB and 24 NW, 14.7 ± 1.5 years), comparing autonomic indices provided by HRV and T4S. Body fractioning was determined employing dual-energy x-ray absorptiometry (DXA). MAIN RESULTS The cardiac vagal index (CVI) obtained from T4S and standard time- and frequency-domain HRV measures were lower in OB versus NW (P ⩽ 0.05). Correlations between CVI and HRV indices of cardiac vagal modulation were as follows: CVI versus RMSSD (r = 0.44; P = 0.003); CVI versus pNN50 (r = 0.32; P = 0.04); CVI versus HF (r = 0.35; P = 0.02). Associations between body fat, android/gynoid ratio, and percent trunk fat versus CVI were of similar magnitude and direction than versus HRV indices. SIGNIFICANCE The T4S proved to be adequate to detect cardiac parasympathetic impairment in obese adolescents. Moreover, vagal modulation assessed by HRV and T4S inversely correlated with visceral adipose tissue. These findings along with the simplicity and safety of the T4S should encourage its use in the assessment of cardiac parasympathetic modulation in obese pediatric populations.

The evidence that quality of life is a positive variable for the survival of cancer patients has prompted the interest of the health and pharmaceutical industry in considering that variable as a final clinical outcome. Sustained improvements in cancer care in recent years have resulted in increased numbers of people living with and beyond cancer, with increased attention being placed on improving quality of life for those individuals. Connected Health provides the foundations for the transformation of cancer care into a patient-centric model, focused on providing fully connected, personalized support and therapy for the unique needs of each patient. Connected Health creates an opportunity to overcome barriers to health care support among patients diagnosed with chronic conditions. This paper provides an overview of important areas for the foundations of the creation of a new Connected Health paradigm in cancer care. Here we discuss the capabilities of mobile and wearable technologies; we also discuss pervasive and persuasive strategies and device systems to provide multidisciplinary and inclusive approaches for cancer patients for mental well-being, physical activity promotion, and rehabilitation. Several examples already show that there is enthusiasm in strengthening the possibilities offered by Connected Health in persuasive and pervasive technology in cancer care. Developments harnessing the Internet of Things, personalization, patient-centered design, and artificial intelligence help to monitor and assess the health status of cancer patients. Furthermore, this paper analyses the data infrastructure ecosystem for Connected Health and its semantic interoperability with the Connected Health economy ecosystem and its associated barriers. Interoperability is essential when developing Connected Health solutions that integrate with health systems and electronic health records. Given the exponential business growth of the Connected Health economy, there is an urgent need to develop mHealth (mobile health) exponentially, making it both an attractive and challenging market. In conclusion, there is a need for user-centered and multidisciplinary standards of practice to the design, development, evaluation, and implementation of Connected Health interventions in cancer care to ensure their acceptability, practicality, feasibility, effectiveness, affordability, safety, and equity. European Cooperation in Science and Technology (COST) ENJECT TD 1405 European Union's Horizon 2020 grant number: 722012 Tatra banka Foundation (2018vs108) Research Agency in Slovakia (ITMS: 26240120038) Fundação para a Ciência e a Tecnologia (FCT) SFRH/BSAB/142983/2018 Fundação para a Ciência e a Tecnologia (FCT) UID/DTP/00617/2019

PURPOSE This paper presents a novel method to compute oesophageal transit velocity in a direct and automatized manner by the registration of scintigraphy images. METHODS A total of 36 images from nine healthy volunteers were processed. Four dynamic image series per volunteer were acquired after a minimum 8 h fast. Each acquisition was made following the ingestion of 5 ml saline labelled with about 26 MBq (700 µCi) technetium-99m phytate in a single swallow. Between the acquisitions, another two swallows of 5 ml saline were performed to clear the oesophagus. The composite acquired files were made of 240 frames of anterior and posterior views. Each frame is the accumulate count for 250 ms.At the end of acquisitions, the images were corrected for radioactive decay, the geometric mean was computed between the anterior and posterior views and the registration of a set of subsequent images was performed. Utilizing the improved Demons technique, we obtained from the deformation field the regional resultant velocity, which is directly related to the oesophagus transit velocity. RESULTS The mean regional resulting velocities decreases progressively from the proximal to the distal oesophageal portions and, at the proximal portion, is virtually identical to the primary peristaltic pump typical velocity. Comparison between this parameter and 'time-activity' curves reveals consistency in velocities obtained using both methods, for the proximal portion. CONCLUSION Application of the improved Demons technique, as an easy and automated method to evaluate velocities of oesophageal bolus transit, is feasible and seems to yield consistent data, particularly for the proximal oesophagus.

Objectives This in vivo study compared the protein profile of the acquired enamel pellicle (AEP) in volunteers 1) with gastroesophageal reflux disease (GERD) and erosive tooth wear (ETW) (BEWE ≥ 9; GE group); 2) with GERD without ETW (BEWE = 0; GNE group) and 3) control (without GERD and BEWE = 0; C group). Materials and methods Twenty-four subjects (8/group) participated. AEP was formed during 120 min and collected. After protein extraction, the samples were submitted to reverse phase liquid chromatography coupled to mass spectrometry. Label-free proteomic quantification was performed using Protein Lynx Global Service software. Results In total, 458 proteins were identified. Seventy-six proteins were common to all the groups. The proteomic profile of the AEP was quite different among the distinct groups. The numbers of proteins exclusively found in the C, GE and GNE groups were 113, 110 and 81, respectively. Most of the proteins exclusively identified in the C and GNE groups bind metals, while those in the GE group are mainly membrane proteins. Many proteins were found exclusively in the reflux groups. In the quantitative analyses, when the GNE group was compared with the GE group, the proteins with the highest decreases were Lysozyme C, Antileukoproteinase, Cathepsin G, Neutrophil defensins and Basic salivary proline-rich proteins, while those with the highest increases were subunits of Hemoglobin, Albumin and isoforms of Cystatin. Conclusion Profound alterations in the proteomic profile of the AEP were seen in GNE compared with GE volunteers, which might play a role in the resistance to ETW seen in the first. Clinical significance This pioneer study compared the proteomic profile of the AEP of patients with GERD with or without ETW. Increased proteins in those without ETW might be protective and are good candidates to be added to dental products to protect against erosion caused by intrinsic acids.

OBJECTIVE: The 13C-urea breath test is the main non-invasive test for the diagnosis of Helicobacter pylori infection. The availability of this test throughout the country is limited, mainly due to the difficulty in obtaining the labeled isotope from abroad. Recently, researchers from the Nuclear Energy Center in Agriculture at the University of São Paulo (CENA/USP) succeeded in synthesizing 13C-enriched urea for Helicobacter pylori diagnosis. The aim of the study was to compare the performance of the 13C-urea breath test using 13C-urea acquired abroad with that of a test using 13C-urea synthesized in Brazil. METHOD: Sixty-four dyspeptic patients participated in the study (24 men and 40 women). Initially, the patients performed the 13C-urea breath test using the imported substrate (Euriso-Top, France). Seven to fourteen days later, all the patients repeated the test using the Brazilian substrate. The samples from both examinations were processed in an infrared isotope analyzer (IRIS, Wagner Analisen Technik, Germany), and all delta over baseline (DOB) [%] values above four were considered positive results. RESULTS: Twenty-seven patients (42%) exhibited negative results for Helicobacter pylori infection, and thirty-seven patients (58%) exhibited positive results when tested using the foreign substrate (gold standard). There was a 100% concordance regarding the presence or absence of infection when the gold standard results were compared with those obtained using the Brazilian substrate. CONCLUSIONS: Similar performance in the diagnosis of Helicobacter pylori infection was demonstrated when using the 13C-urea breath test with the Brazilian 13C-urea substrate and the test with the substrate produced abroad. This validation represents an important step toward increasing the availability of the 13C-urea breath test throughout the country, which will have a positive influence on the management of Helicobacter pylori infection.

Made available in DSpace on 2018-11-26T15:43:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-03-21 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundacao de Amparo a Pesquisa do estado de Goias (FAPEG) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Background: We introduce and demonstrate that the AC biosusceptometry (ACB) technique enables real-time monitoring of magnetic nanoparticles (MNPs) in the bloodstream. We present an ACB system as a simple, portable, versatile, non-invasive, and accessible tool to study pharmacokinetic parameters of MNPs, such as circulation time, in real time. We synthesized and monitored manganese doped iron oxide nanoparticles in the bloodstream of Wistar rats using two different injection protocols. Aiming towards a translational approach, we also simultaneously evaluated cardiovascular parameters, including mean arterial pressure, heart rate, and episodes of arrhythmia in order to secure the well-being of all animals. Results: We found that serial injections increased the circulation time compared with single injections. Immediately after each injection, we observed a transitory drop in arterial pressure, a small drop in heart rate, and no episodes of arrhythmia. Although some cardiovascular effects were observed, they were transitory and easily recovered in both protocols. Conclusions: These results indicate that the ACB system may be a valuable tool for in vivo, real-time MNP monitoring that allows associations with other techniques, such as pulsatile arterial pressure and electrocardiogram recordings, helping ensuring the protocol safety, which is a fundamental step towards clinical applications. Sao Paulo State Univ, Biosci Inst Botucatu, Botucatu, SP, Brazil Univ Fed Goias, Inst Phys, Goiania, Go, Brazil Univ Sao Paulo, Ribeirao Preto Sch Med, Ribeirao Preto, SP, Brazil Univ Fed Goias, Inst Fis, BR-74690900 Goiania, Go, Brazil Sao Paulo State Univ, Biosci Inst Botucatu, Botucatu, SP, Brazil

Immunosuppressive therapy after kidney transplant is necessary to prevent allograft rejection and it is the cause of several gastrointestinal (GI) disorders that have been scantily studied. This study was aimed at investigating the influence of triple immunosuppressive therapy on GI transit in renal transplant patients by employing a biomagnetic technique. Twenty-one renal transplant patients underwent triple therapy, which included either tacrolimus (TAC) or cyclosporin A (CsA) associated with prednisone and azathioprine. They were all evaluated, and fifteen other healthy individuals formed the control group. After a standardized meal, GI transit of magnetic markers was assessed using Alternating Current Biosusceptometry (ACB). Patients taking TAC had significantly accelerated gastric emptying and colonic arrival (p ≤ 0.001) when compared with those taking CsA and those in the control group. However, no differences were observed in small bowel transit among the groups studied. Overall, the inter-subject coefficients of variation for gastrointestinal transit parameters were higher for the TAC group and similar for the CsA and control groups. This study demonstrated that ACB is a suitable methodology when evaluating the influence of different immunosuppressive therapies on gastrointestinal transit after renal transplantation. Pronounced inter-individual variation was found in patients treated with tacrolimus, thus showing the prokinetic effect of this drug on GI motility. Studies of motility patterns in this population could be useful as complementary information toward determining the mechanisms and the relationship between motility and therapeutic doses.

Arteriovenous anastomoses disrupt cardiovascular and renal homeostasis, eliciting hemodynamic adjustments, resetting the humoral pattern, and inducing cardiac hypertrophy. Because acute circulatory imbalance alters gut motor behavior, we studied the effects of arteriovenous fistula placement on the gastric emptying (GE) of a liquid meal in awake rats. After laparotomy, we created an aortocaval fistula (ACF) by aorta and cava wall puncture with a 21-, 23-, or 26-gauge needle. The ACF was not created in the control group, which underwent sham operation. After 12, 24, or 48 h, mean arterial pressure, heart rate, and central venous pressure were continuously recorded, and cardiac output was estimated by thermal dilution. The rats were then gavage fed a test meal (i.e., phenol red in glucose solution), and fractional dye retention was determined 10, 20, or 30 min later. The effect of prior bleeding on ACF-induced GE delay, the role of neuroautonomic pathways, and changes in plasma hormone levels (i.e., angiotensin II, arginine vasopressin, atrial natriuretic peptide, corticosterone, and oxytocin) were evaluated. When compared with the sham-operated group, ACF rats exhibited arterial hypotension, higher ( P < 0.05) heart rate, central venous pressure, and cardiac output values and increased ( P < 0.05) gastric dye retention, a phenomenon prevented by bilateral subdiaphragmatic vagotomy and hexamethonium treatment. Pirenzepine also impaired the occurrence of gastric delay in subjects with ACF. In addition to causing hyperkinetic circulation, ACF placement delayed the GE of liquid in awake rats, an effect that likely involves a parasympathetic pathway.

Made available in DSpace on 2018-11-26T17:34:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) We describe the development of a joint in vivo/ex vivo protocol to monitor magnetic nanoparticles in animal models. Alternating current biosusceptometry (ACB) enables the assessment of magnetic nanoparticle accumulation, followed by quantitative analysis of concentrations in organs of interest. We present a study of real-time liver accumulation, followed by the assessment of sequential biodistribution using the same technique. For quantification, we validated our results by comparing all of the data with electron spin resonance (ESR). The ACB had viable temporal resolution and accuracy to differentiate temporal parameters of liver accumulation, caused by vasculature extravasation and macrophages action. The biodistribution experiment showed different uptake profiles for different doses and injection protocols. Comparisons with the ESR system indicated a correlation index of 0.993. We present the ACB system as an accessible and versatile tool to monitor magnetic nanoparticles, allowing in vivo and real-time evaluations of distribution and quantitative assessments of particle concentrations. (C) 2017 Elsevier Inc. All rights reserved. Univ Estadual Paulista, Dept Fis & Biofis, Lab Biomagnetismo, IBB, Botucatu, SP, Brazil Univ Fed Goias, Inst Fis, Goiania, Go, Brazil Univ Texas MD Anderson Canc Ctr, Dept Expt Radiat Oncol, Houston, TX 77030 USA Univ Estadual Paulista, Fac Med Botucatu, Dept Doencas Trop & Diagnost Imagem, Botucatu, SP, Brazil Univ Sao Paulo, Fac Med Ribeirao Preto, Ribeirao Preto, SP, Brazil Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Fis, Ribeirao Preto, SP, Brazil Univ Estadual Paulista, Dept Fis & Biofis, Lab Biomagnetismo, IBB, Botucatu, SP, Brazil Univ Estadual Paulista, Fac Med Botucatu, Dept Doencas Trop & Diagnost Imagem, Botucatu, SP, Brazil FAPESP: 2010/07639-9 FAPESP: 2011/18696-6 FAPESP: 2013/20842-6 FAPESP: 2015/14914-0

Made available in DSpace on 2018-11-26T15:30:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-07-07 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) AIM: To correlate gastric contractility, gastrointestinal transit, and hormone levels in non-pregnant (estrous cycle) and pregnant rats using noninvasive techniques. METHODS: Female rats (n = 23) were randomly divided into (1) non-pregnant, (contractility, n = 6; transit, n = 6); and (2) pregnant (contractility, n = 5; transit, n = 6). In each estrous cycle phase or at 0, 7, 14, and 20 d after the confirmation of pregnancy, gastrointestinal transit was recorded by AC biosusceptometry (ACB), and gastric contractility was recorded by ACB and electromyography. After each recording, blood samples were obtained for progesterone and estradiol determination. RESULTS: In the estrous cycle, despite fluctuations of sex hormone levels, no significant changes in gastrointestinal motility were observed. Days 7 and 14 of pregnancy were characterized by significant changes in the frequency of contractions (3.90 +/- 0.42 cpm and 3.60 +/- 0.36 cpm vs 4.33 +/- 0.25 cpm) and gastric emptying (168 +/- 17 min and 165 +/- 15 min vs 113 +/- 15 min) compared with day 0. On these same days, progesterone levels significantly increased compared with control (54.23 +/- 15.14 ng/mL and 129.96 +/- 30.52 ng/mL vs 13.25 +/- 6.31 ng/mL). On day 14, we observed the highest level of progesterone and the lowest level of estradiol compared with day 0 (44.3 +/- 15.18 pg/mL vs 24.96 +/- 5.96 pg/mL). CONCLUSION: Gastrointestinal motility was unaffected by the estrous cycle. In our data, high progesterone and low estradiol levels can be associated with decreased contraction frequency and slow gastric emptying. Sao Paulo State Univ, BR-18618970 Botucatu, SP, Brazil Univ Fed Mato Grosso, Inst Ciencias Biol & Saude, Ave Valdon Varjao 6390, BR-78600000 Barra Do Garcas, MT, Brazil Univ Estadual Ciencias Saude Alagoas, BR-57010300 Maceio, AL, Brazil Univ Sao Paulo, BR-14049900 Ribeirao Preto, SP, Brazil Sao Paulo State Univ, BR-18618970 Botucatu, SP, Brazil FAPESP: 2010/14845-4 FAPESP: 2015/14923-9 CNPq: 150456/2009-3

Objective: To investigate the effects of rapid anesthesia and long-term sedation with the essential oils (EOs) of Myrcia sylvatica (EOMS) and Curcuma longa (EOCL) on biochemical and oxidative parameters in matrinxã. Study design: Prospective, randomized, laboratory experiment. Animals: A total of 72 matrinxã (Brycon amazonicus) adults weighing 404.8 ± 27.9 g were divided into eight groups of nine fish. Methods: Biochemical and oxidative effects were investigated in plasma and tissues of matrinxã subjected to rapid anesthesia (5 minutes) or long-term sedation (360 minutes, simulating the practice of transport) with EOMS (200 μL L−1 and 10 μL L−1, respectively) and EOCL (500 μL L−1 and 40 μL L−1, respectively). Results: Transport simulation without sedation or anesthesia increased lipid peroxidation levels in the gills and kidney of fish in the control group. Anesthesia and sedation with EOs decreased cortisol concentrations and increased lactate concentrations compared with controls. Lipid peroxidation was lower in the brain, gills, liver and kidney of sedated and anesthetized fish, than in the control group. Anesthesia with EOs increased the activity of superoxide dismutase and glutathione-S-transferase in the brain, and catalase in the liver and gills, compared with controls. Long-term sedation with EOs increased superoxide dismutase, glutathione peroxidase and glutathione reductase activities in the brain, catalase in the liver, glutathione peroxidase and glutathione reductase in the gills and superoxide dismutase in the kidney. In general, nonprotein thiols content and total reactive antioxidant potential of tissues were higher after anesthesia and sedation with EOs compared with the control group. Conclusions and clinical relevance: The concentrations of EOMS and EOCL used were effective at preventing a stress response and excess of reactive oxygen species formation. For these reasons, these substances may be recommended for use in the transportation of fish to improve survival and animal welfare. Fil: Saccol, Etiane M. H.. Universidad Federal de Santa Maria; Brasil Fil: Londero, Érika P.. Universidad Federal de Santa Maria; Brasil Fil: Bressan, Caroline A.. Universidad Federal de Santa Maria; Brasil Fil: Salbego, Joseânia. Universidad Federal de Santa Maria; Brasil Fil: Gressler, Luciane T.. Universidad Federal de Santa Maria; Brasil Fil: Silva, Lenise V. F.. Universidade Federal do Pará; Brasil Fil: Mourão, Rosa H. V.. Universidade Federal do Pará; Brasil Fil: Oliveira, Ricardo B.. Universidad Federal de Santa Maria; Brasil Fil: Llesuy, Susana Francisca. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina Fil: Baldisserotto, Bernardo. Universidad Federal de Santa Maria; Brasil Fil: Pavanato, Maria A.. Universidad Federal de Santa Maria; Brasil

BackgroundGastrointestinal (GI) complications are common after renal transplantation, mainly owing to immunosuppressive therapy. Assessment of GI transit time can facilitate rational management of these disorders.ObjectiveWe evaluate the GI transit parameters in renal transplant recipients taking tacrolimus, azathioprine, and prednisone with the use of the alternate current biosusceptometry (ACB) technique and compared them with healthy volunteers.MethodsTen renal transplant recipients and 10 healthy volunteers were enrolled in this study. After an overnight fast, patients and volunteers ingested a standard meal containing magnetic markers. The biomagnetic monitoring was performed at 10-minute intervals for at least 8 hours to obtain gastric emptying as well as the colonic arrival time–intensity curves. Mean gastric emptying time (MGET), mean colon arrival time (MCAT), and mean small intestinal transit time (MSITT) were quantified and compared between control and patient groups with results expressed as mean ± SD.ResultsThe MGET measured by the ACB technique was 48 ± 31 minutes and 197 ± 50 minutes for patients and healthy subjects, respectively. MSITT and MCAT values calculated for patients versus volunteers were 171 ± 71 minutes versus 197 ± 71 minutes and 219 ± 83 minutes versus 373 ± 52 minutes, respectively. Renal transplant recipients showed significantly faster; gastric emptying and colon arrival times (P < .001) compared with normal volunteers; however, small intestinal transit time was not significantly different (P = .44).ConclusionsIn stable renal transplant recipients, the GI transit parameters were significantly faster than in normal healthy volunteers. ACB sensors are versatile technologies that can be used for clinical research, because they offer an excellent opportunity to evaluate GI transit in a noninvasive manner without the use of ionizing radiation.

Aim Stapled haemorrhoidopexy may damage the anorectal musculature and its sensorimotor function. Most studies have not used a barostat for the measurement of compliance. This study aimed to investigate the effect of stapled haemorrhoidopexy on rectal compliance and sensitivity. Method After Ethical Committee approval, we studied 10 male patients (mean age 33.8 years) with third- or fourth-degree haemorrhoids. Rectal compliance and sensitivity were measured with a 600-ml bag and an electronic barostat. Volunteers were submitted to two consecutive rectal distension protocols, including continuous distension at 2, 4 and 6 months after stapled haemorrhoidopexy. Intraluminal volume and pressure were recorded, including the first rectal sensation, desire to defecate and onset of rectal pain. Another group of 10 male control patients (mean age 24.9 years) with pilonidal sinus and no haemorrhoids was also included in the study. Results Two months after stapled haemorrhoidopexy, rectal compliance decreased (7.1 ± 0.2 vs 5.3 ± 0.1, 6.4 ± 0.1 vs 5.1 ± 0.1 and 5.6 ± 0.2 vs 4.7 ± 0.1 ml/mmHg for first rectal sensation, desire to defecate and rectal pain, respectively; P

Biomagnetic methods have been designed for a wide range of applications. Recently, such methods have been proposed as alternatives to scintigraphy for evaluating of a number of pharmaceutical processes in vitro as well as under the influence of gastrointestinal physiological parameters. In this review, physical characterization as well as the most recent applications of Superconducting Quantum Interference Device (SQUID), Anisotropic Magnetoresistive (AMR) and AC Biosusceptometry (ACB) in the pharmaceutical research will be explored. Moreover, their current status and how these technologies can be employed to improve the knowledge about the impact of gastrointestinal physiology on drug delivery in association with pharmacokinetic outcomes, termed pharmacomagnetography, will be presented.

Reduced food intake, appetite loss and alteration of ghrelin and PYY(3-36) secretion have been suggested to have a function in the loss of body weight commonly observed after gastrectomy. The objective of this study was to investigate the circulating concentrations of ghrelin and PYY(3-36) and their relationships with food intake, appetite and resting energy expenditure (REE) after gastrectomy plus vagotomy.Seven patients with total gastrectomy (TG), 14 with partial gastrectomy (PG) and 10 healthy controls were studied. Habitual food intake and REE was assessed; fasting and postprandial plasma total ghrelin, PYY(3-36) concentrations and appetite ratings were determined after ingestion of a liquid test meal.Differently from PG and controls, fasting ghrelin correlated with REE, and a higher energy intake was observed in the TG group. Fasting plasma ghrelin concentrations were lower in TG compared with controls, and no ghrelin response to the meal was observed in either PG or TG. Fasting plasma PYY(3-36) concentrations were not different among the groups. There was an early and exaggerated postprandial rise in PYY(3-36) levels in both PG and TG groups, but not in controls. No effect of ghrelin or PYY(3-36) concentrations was observed on hunger, prospective consumption or fullness ratings.Total ghrelin and PYY(3-36) do not seem to be involved with appetite or energy intake regulation after gastrectomy plus vagotomy. Ghrelin secreted by sources other than stomach is likely to have a function in the long-term regulation of body weight after TG.

Association techniques could be the answer for evaluating electromechanical coupling and gastric emptying under basal conditions and after administration of drugs. Electrogastrography (EGG) and alternating current biosusceptometry (ACB) emerged due to their interesting nature, noninvasiveness and low cost. The aims were to examine in dogs the effect of erythromycin on gastric emptying by ACB and electrical and motor responses to erythromycin and propranolol by ACB and EGG respectively. Twelve beagle dogs ingested a solid test meal on separate days. Under anesthesia, gastric motility was evaluated by EGG and ACB after erythromycin and propranolol administration. Without anesthesia, gastric emptying was assessed under basal conditions and after erythromycin by ACB. ACB and EGG showed a strong temporal correlation. Erythromycin and propranolol presented the same profile with different power ratios; the amplitude increased whereas frequency decreased. Also, erythromycin administration hastened gastric emptying while reducing the orocaecal transit time. There is a demand for reliable, easy-to-perform and comfortable techniques to record gastric emptying and gastric activity in medicine and veterinary practice. In summary, the association of ACB with EGG accompanied by an appropriate animal model is promising for evaluating effects of drugs in gastric myoelectrical and contractile activity.

To evaluate gastrointestinal motility during 5-fluorouracil (5-FU)-induced intestinal mucositis. Wistar rats received 5-FU (150 mg kg−1, i.p.) or saline. After the 1st, 3rd, 5th, 15th and 30th day, sections of duodenum, jejunum and ileum were removed for assessment of epithelial damage, apoptotic and mitotic indexes, MPO activity and GSH concentration. In order to study gastrointestinal motility, on the 3rd or 15th day after 5-FU treatment, gastric emptying in vivo was measured by scintilographic method, and stomach or duodenal smooth muscle contractions induced by CCh were evaluated in vitro. On the third day of treatment, 5-FU induced a significant villi shortening, an increase in crypt depth and intestinal MPO activity and a decrease in villus/crypt ratio and GSH concentration. On the first day after 5-FU there was an increase in the apoptosis index and a decrease in the mitosis index in all intestinal segments. After the 15th day of 5-FU treatment, a complete reversion of all these parameters was observed. There was a delay in gastric emptying in vivo and a significant increase in gastric fundus and duodenum smooth muscle contraction, after both the 3rd and 15th day. 5-FU-induced gastrointestinal dysmotility outlasts intestinal mucositis.

Sildenafil slows down the gastric emptying of a liquid test meal in awake rats and inhibits the contractility of intestinal tissue strips. We studied the acute effects of sildenafil on in vivo intestinal transit in rats. Fasted, male albino rats (180-220 g, N = 44) were treated (0.2 mL, iv) with sildenafil (4 mg/kg) or vehicle (0.01 N HCl). Ten minutes later they were fed a liquid test meal (99m technetium-labeled saline) injected directly into the duodenum. Twenty, 30 or 40 min after feeding, the rats were killed and transit throughout the gastrointestinal tract was evaluated by progression of the radiotracer using the geometric center method. The effect of sildenafil on mean arterial pressure (MAP) was monitored in a separate group of rats (N = 14). Data (medians within interquartile ranges) were compared by the Mann-Whitney U-test. The location of the geometric center was significantly more distal in vehicle-treated than in sildenafil-treated rats at 20, 30, and 40 min after test meal instillation (3.3 (3.0-3.6) vs 2.9 (2.7-3.1); 3.8 (3.4-4.0) vs 2.9 (2.5-3.1), and 4.3 (3.9-4.5) vs 3.4 (3.2-3.7), respectively; P < 0.05). MAP was unchanged in vehicle-treated rats but decreased by 25% (P < 0.05) within 10 min after sildenafil injection. In conclusion, besides transiently decreasing MAP, sildenafil delays the intestinal transit of a liquid test meal in awake rats.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2014-02-26T17:00:41Z No. of bitstreams: 1 WOS000249845300005.pdf: 271464 bytes, checksum: 7e50f44b347f595115846327da97fdb5 (MD5) Made available in DSpace on 2014-02-26T17:00:41Z (GMT). No. of bitstreams: 1 WOS000249845300005.pdf: 271464 bytes, checksum: 7e50f44b347f595115846327da97fdb5 (MD5) Previous issue date: 2007-10-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:32:51Z No. of bitstreams: 1 WOS000249845300005.pdf: 271464 bytes, checksum: 7e50f44b347f595115846327da97fdb5 (MD5) Made available in DSpace on 2014-05-20T13:32:51Z (GMT). No. of bitstreams: 1 WOS000249845300005.pdf: 271464 bytes, checksum: 7e50f44b347f595115846327da97fdb5 (MD5) Previous issue date: 2007-10-01 Abnormal intragastric distribution of food (IDF) and a phasic contractility in the proximal stomach have been related to dyspeptic symptoms. Thus, the behaviour of the stomach and the proximal region, in particular, continues to attract attention and demand for reliable and comfortable techniques. The aims of this study were to employ AC Biosus-ceptometry (ACB) and scintigraphy to evaluate IDF and gastric motor activity in humans. Fifteen healthy volunteers ingested 60 mL of yogurt containing 2 mCi of Tc-99m and 4 g of ferrite. Each volunteer had gastric motility and IDF evaluated twice on separate days; on one occasion by ACB and another by scintigraphy. Digital signal processing was performed in MatLab (Mathworks Inc., Natick, MA, USA). Results were expressed as mean +/- SD. Similar results of distal accumulation time (P < 0.001) were obtained for scintigraphy (6.93 +/- 3.25 min) and for ACB (7.04 +/- 3.65 min). Fast Fourier Transform revealed two dominant frequencies (P > 0.9). Besides the well-know frequency of 3 cpm, our results showed identical frequencies in proximal stomach recordings (P < 0.001) for scintigraphic (1.01 +/- 0.01 cpm) and ACB (0.98 +/- 0.06 cpm). In summary, our data showed that scintigraphy and ACB are promising techniques to evaluate several aspects of gastric motility. Moreover, ACB is non-invasive, radiation-free and deserves the same importance as conventional methods for this kind of analysis. Univ Estadual Paulista, Lab Biomagnet, Inst Biociencias IBB, Dept Fis & Biofis, BR-18618000 São Paulo, Brazil Univ Estadual Paulista, FMB, Dept Clin Med, BR-18618000 São Paulo, Brazil Univ São Paulo, FFCLRP, Dept Fis & Matemat, São Paulo, Brazil Univ São Paulo, FMRP, Dept Clin Med, São Paulo, Brazil Univ São Paulo, FMRP, Dept Fisiol, São Paulo, Brazil Univ Estadual Paulista, Lab Biomagnet, Inst Biociencias IBB, Dept Fis & Biofis, BR-18618000 São Paulo, Brazil Univ Estadual Paulista, FMB, Dept Clin Med, BR-18618000 São Paulo, Brazil

We employed ACB to characterize Gastric Emptying Time (GET — T1/2) and Gastric Activity Contraction (GAC) in dogs after erythromycin administration. An erythromycin dose of 50 mg was infused, after 24 h of fasting. Without erythromycin administration, ACB recorded GET of 157.5±13.6 min (mean±SD) and GAC of 4.4±0.5 cpm (cycles per minute). After erythromycin administration was measured a GET of 84.2±19.7 min. GAC was measured before, during and after erythromycin administration and results were, respectively, 4.4±0.5, 4.9±0.6 and 4.2±0.3 cpm. Erythromycin produced efficient prokinetic action in gastric emptying and increased gastric motility in dogs. © 2007 Elsevier B.V. All rights reserved.

The biomagnetic technique called Alternate Current Biosusceptometry (ACB) is a proposal to evaluate a multiparticulate drug delivery system in the human gastrointestinal tract. Results show that ACB was able to quantify the gastrointestinal transit and spreading of the magnetic material and is an attractive tool for pharmaceutical research.

Background: Patients with alcohol-related chronic pancreatitis (ARCP) may present with abnormal gastric emptying (GE), which has been ascribed mainly to nutrient maldigestion. Nevertheless, many patients also have diabetes with autonomic dysfunction and malnutrition and the role of these factors on abnormal GE has not been investigated. Goals: To determine the influences of malabsorption, diabetes, malnutrition, and autonomic dysfunction on GE abnormalities in patients with ARCP. Study: Forty ARCP outpatients and 18 healthy controls were studied. GE was measured by scintigraphy after a standard, liquid, nutrient meal labeled with 99 m Technetium-phytate. Autonomic function was evaluated by cardiovascular tests. The influence of each factor on abnormal GE was assessed by Bayesian multiple regression analysis. Results: In the ARCP group, GE was abnormal in 19 patients (47.5%), who showed either accelerated (N = 12) or delayed emptying (N = 7). Diabetes was highly prevalent (P < 0.01) in ARCP patients with either rapid or delayed GE (18/19). Multiple regression analysis showed that not only diabetes, but also autonomic dysfunction has significant effects on abnormal GE, whereas malabsorption and malnutrition seemed not to be associated to abnormal emptying. Conclusions: A substantial proportion of patients with ARCP may have abnormal GE. Either delayed or accelerated GE seem to be related to underlying diabetes mellitus and autonomic neuropathy rather than to nutrient malabsorption and malnutrition.

Background This study proposes an experimental model to assess the consequences of gastric surgeries on gastric motility. We investigated the effects of proximal gastrectomy (PG) using a non-invasive technique (alternate current biosusceptometry [ACB]) on gastric contractility (GC), gastric emptying (GE), and orocecal transit (OCT) after the ingestion of liquids and solids in rats. Methods Twenty-four male rats were subjected to gastric motility assessment before and after the PG procedure. The GE and OCT results are expressed as the mean time of gastric emptying (MGET) and cecum arrival (MCAT). The GC recordings are presented as the frequency and amplitude of contractions. Key Results Mean time of gastric emptying after solid meals were significantly different (p

The distribution of intragastric contents has been studied using operator-dependent methods. We devised an automated technique for determining post-prandial intragastric distribution of radiolabeled meals, based on the calculation of the 'center of activity' (CA) of the radioactivity contained in the stomach in any given scintigraphic image. Twelve healthy volunteers and eleven functional dyspepsia (FD) patients ingested a liquid meal (320 mL, 450 kcal) labeled with 99mTechnetium-phytate. Images of the stomach were acquired every 5–10 min for 2 h, and counted to determine the percentage of total activity retained in the upper half of the stomach, as visually delineated. Each image was then processed using an algorithm for calculating a CA value representing the average of image-forming points corrected by pixel number. The relative CA position along the main longitudinal axis of the stomach, as defined by a digital 'skeletonizing' process, was expressed in a '0 to 1' scale. In the FD patients, the average of all CA determinations was significantly higher than in the controls (0.56, 0.30–0.80 versus 0.48, 0.33–0.68, p < 0.05) and correlated significantly with proximal stomach retention values assessed by a visual method (R = −0.64, p < 0.001). Assessing post-prandial intragastric distribution by a novel automated method is feasible and yields reliable data, while being much less operator dependent.

Oral administration of solid dosage forms is usually preferred in drug therapy. Conventional imaging methods are essential tools to investigate the in vivo performance of these formulations. The non-invasive technique of ac biosusceptometry has been introduced as an alternative in studies focusing on gastrointestinal motility and, more recently, to evaluate the behaviour of magnetic tablets in vivo. The aim of this work was to employ a multisensor ac biosusceptometer system to obtain magnetic images of disintegration of tablets in vitro and in the human stomach. The results showed that the transition between the magnetic marker and the magnetic tracer characterized the onset of disintegration (t(50)) and occurred in a short time interval (1.1 +/- 0.4 min). The multisensor ac biosusceptometer was reliable to monitor and analyse the in vivo performance of magnetic tablets showing accuracy to quantify disintegration through the magnetic images and to characterize the profile of this process.

RACIONAL: O tratamento convencional de Helicobacter pylori consiste na utilização de antimicrobianos, aos quais uma minoria expressiva de pacientes não responde. Tratamentos alternativos para a infecção têm sido propostos, incluindo o uso de antioxidantes. Destaque crescente tem sido atribuído à vitamina C ao se demonstrar que concentrações da mesma no estômago de indivíduos infectados com H. pylori são substancialmente menores do que as de indivíduos saudáveis. Doses farmacológicas de vitamina C foram investigadas na erradicação de H. pylori com resultados controversos. OBJETIVO: Avaliar o efeito da administração via oral de vitamina C sobre a colonização de estômago por H. pylori em pacientes infectados, com gastrite crônica ou com úlcera péptica cujos tratamentos convencionais não resultaram em erradicação. MATERIAL E MÉTODOS: Protocolo I: estudo aleatório, duplo-cego, controlado por placebo em pacientes com gastrite crônica, sem tratamento prévio para a infecção. Protocolo II: estudo aberto, não controlado em pacientes com úlcera péptica e pelo menos dois tratamentos prévios de erradicação. O tratamento consistiu em vitamina C 5 g/dia durante 28 dias consecutivos. Seu efeito foi avaliado pelo teste respiratório com 14C-uréia quanto à taxa de erradicação, à variação de radioatividade e à supressão da infecção. RESULTADOS: No protocolo I, 38 pacientes completaram o estudo, 21 recebendo vitamina C e 17 recebendo placebo durante 28 dias. A taxa de erradicação "por protocolo" com vitamina C foi zero, intervalo de confiança de 95%: 0%-15%. No protocolo II, oito pacientes completaram o tratamento. A taxa de erradicação foi zero, com intervalo de confiança de 95%: 05-32%. Não houve diminuição da carga bacteriana. CONCLUSÕES: A administração de vitamina C na dosagem diária de 5 g durante 28 dias não é eficaz na erradicação de infecção por H. pylori, nem altera quantitativamente sua carga no estômago dos pacientes infectados.

A study of the mechanical activity of the large intestine using remanent magnetization (RM) measurement of ingested magnetic tracers is presented. A fluxgate magnetometer is employed to record the movements of magnetic tracers previously ingested by the subject and contained in the right colon. An intense short magnetic pulse magnetizes the magnetic tracers producing a RM and the magnetic content movement in the right colon is assessed by the variations of the RM. The method was capable of revealing both the stimulatory effect of the ingestion of a meal and the reducing effect of an anti-cholinergic drug on the colonic transit in normal subjects.

Made available in DSpace on 2022-04-28T19:56:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-01-01 Oral administration is the most convenient route for drug therapy. The knowledge of the gastrointestinal transit and specific site for drug delivery is a prerequisite for development of dosage forms. The aim of this work was to demonstrate that is possible to monitor the disintegration process of film-coated magnetic tablets by multi-sensor alternate current Biosusceptometry (ACB) in vivo and in vitro. This method is based on the recording of signals produced by the magnetic tablet using a seven sensors array and signal-processing techniques. The disintegration was confirmed by signals analysis in healthy human volunteers' measurements and in vitro experiments. Results showed that ACB is efficient to characterize the disintegration of dosage forms in the stomach, being a research tool for the development of new pharmaceutical dosage forms. © 2003 Elsevier B.V. All rights reserved. Department of Pharmacology Biosciences Institute UNESP, Botucatu-SP Department of Physiology Medical School USP, Ribeirão Preto-SP Dept. of Physics and Mathematics FFCLRP USP, Ribeirão Preto-SP Department of Physics and Biophysics Biosciences Institute UNESP, Botucatu-SP Department of Physics and Biophysics Biosciences Institute - IBB Univ. Estadual Paulista - UNESP, CXP 510, CEP 18618-000 Botucatu, Sao Paulo Department of Pharmacology Biosciences Institute UNESP, Botucatu-SP Department of Physics and Biophysics Biosciences Institute UNESP, Botucatu-SP Department of Physics and Biophysics Biosciences Institute - IBB Univ. Estadual Paulista - UNESP, CXP 510, CEP 18618-000 Botucatu, Sao Paulo

The mechanical nature of gastric contraction activity (GCA) plays an important role in gastrointestinal motility. The aim of this study was to detect GCA in anaesthetized dogs, using simultaneously the techniques of AC biosusceptometry (ACB) and manometry, analysing the characteristics of frequency and amplitude (motility index) of GCA, modified by drugs such as prostigmine and N-butyl-scopolamine. The ACB method is based on a differential transformer of magnetic flux and the magnetic tracer works as a changeable external nucleus. This magnetic tracer causes a modification in the magnetic flux, which is detected by the coils. The results obtained from the ACB showed a performance comparable to the manometry in measuring the modifications in the frequency and amplitude of the GCA. We concluded that this ACB technique, non-invasive and free of ionizing radiation, is an option for evaluating GCA and can be employed in future clinical studies.

Gastric emptying reflects a diversity of important physiological functions. Alternating Current Biosusceptometry (ACB) is an inexpensive, radiation-free, and noninvasive method to evaluate gastric emptying, but its response depends on the spatial distribution of the magnetized material and does not have anatomical information. The hybrid transducer - which combines ACB and ultrasound probe - improved susceptometric measurements potential, namely the spatial localization of the magnetized source. This study monitored relative stomach emptying in rats with the aid of the hybrid transducer. Yogurt mixed with ferrite particles was injected into the rats' stomach. The hybrid transducer was placed on the rat's abdominal during experiments. Susceptometric signal and power Doppler (PWD) data were saved and post-processed. In a second experiment, a volumetric image from axial sequences was obtained by means of a transducer displacement system. The relative stomach emptying was evaluated on the bases of PWD images and the susceptometric signal with the hybrid transducer. PWD maps highlighted the movement of magnetic particles (due magnetic force from ACB excitation coils) and showed the rats' stomach location with anatomic information (B-mode). After the acquisition period, the mean relative ACB signal decayed by 4.6 ± 0.1%, and the mean relative PWD area decreased by 4.5 ± 0.2% as a result of stomach emptying. However, these values diminished (∼ 0.5%) when stomach shape was larger and the meal was more widely spread. The distribution spatial was more sensitive to PWD than ACB. The PWD volumetric image provided details of the stomach wall, which may enable minimally invasive detestation of abnormalities. Ultrasound image increased ACB spatial resolution and furnished additional anatomical information.