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Biomedical subjects

F R Silva

Publications and source records attributed to F R Silva.

15 recordsLinked to original sources
PubMed2007

Anorectal three-dimensional endosonography and anal manometry in assessing anterior rectocele in women: a new pathogenesis concept and the basic surgical principle.

OBJECTIVE: The anatomy of the anal canal, the anorectal junction and the lower rectum was studied with 3-D ultrasound. METHOD: Seventeen women with normal bowel transit, without rectocele (group 1) and 17 female patients with a large anterior rectocele (group 2) were examined with a B&K Medical Rawk. Mean age was 44.5 and 51.6 years respectively. In group 1, one (5.8%) patient was nuliparous, five (29.4%) had a caesarian section, 11 (64.7%) had a vaginal delivery while in group 2, two (11.7%) patients were nuliparous, four (23.5%) had a caesarian section and 11 (64.7%) had a vaginal delivery. Images were reconstructed in midline longitudinal (ML) and transverse (T) planes. The external (EAS) and internal (IAS) anal sphincters were measured in both projections. RESULTS: In the ML plane, the EAS length was longer in group 1 (1.94 cm vs 1.61 cm, P < 0.05), the gap length was shorter (1.54 cm vs 1.0 cm P < 0.01) and the wall thickness was shorter in group 2 (0.40 cm vs 0.50 cm P < 0.01). The IAS (0.18 cm vs 0.23 cm P < 0.01) and EAS thickness (0.68 cm vs 0.77 cm, P < 0.05) (left lateral of the posterior quadrant) was greater in group 2. In group 1, the anterior upper anal canal wall in normal females was an extension of the rectal wall and the circular muscle was thicker in the mid-anal canal to form the IAS. In group 2, however, the wall layers were not identified and the IAS was found to be more distal. The differences were not statistically significant in the anal canal resting and squeeze pressures in the two groups. CONCLUSION: Obstetric trauma does not seem to play any role in rectocele pathogenesis because the anal sphincter muscles are anatomically and functionally normal and rectocele is also present in nuliparous and in women with caesarian sections. It seems that it is associated with the absence of EAS and thinner IAS in the anterior upper anal canal. Herniation starts at the upper anal canal extending to the lower rectum in high or large rectoceles and maybe produced by rectal intussusception because of excessive and prolonged straining during defecation. In fact, the denomination 'rectocele' should be changed to 'anorectocele'.

Adult↗
PubMed2005

Transanal repair of rectocele and full rectal mucosectomy with one circular stapler: a novel surgical technique.

We present a new surgical stapling technique for treatment of rectocele when associated with internal mucosal prolapse or haemorrhoids using only one circular mechanical stapler. Eight female patients, mean age 53 years (range, 42-70), complaining of obstructed defecation with vaginal digitation because of rectocele associated with internal mucosal prolapse underwent transanal repair of rectocele and rectal mucosectomy using one circular stapler between April and July 2004. A running horizontal mattress suture was placed through the base of the rectocele including mucosa, submucosa and the muscle layer of the whole anterior anorectal junction wall. The prolapsed mucosa and the muscular layer were then excised with an electrical scapel. A continuous pursestring rectal mucosa suture was placed 0.5 cm before the previous anterior mucosa and muscle layers resected wound, including the anorectal junction wall which was kept separate from the posterior vaginal wall by a Babcock forceps. Posteriorly, the pursestring suture included only mucosal and submucosal layers. The stapled suture was positioned between normal anterior rectal wall and the anal canal, 0.5 cm above the pectinate line. The stapler was then closed, fired and withdrawn. One patient complained of a perianal hematoma on the seventh postoperative day, requiring surgical excision. Postoperative defecography showed correction of the rectocele and outlet obstruction disappeared in all patients. This novel combined manual-stapled technique for rectocele and rectal internal mucosal prolapse seems to be a safe procedure and the preliminary results are encouraging. Further investigations have to be performed to assess long-term outcome in a larger number of patients.

Adult↗
PubMed2001

Effect of 3,5,3'-triiodo-L-thyronine on amino acid accumulation and membrane potential in Sertoli cells of the rat testis.

The purpose of this study was to investigate the effect of T3 on amino acid accumulation and on the membrane potential of Sertoli cells of immature rat testes. Testes of pre-pubertal and pubertal rats were pre-incubated (30 min) in Krebs-Ringer bicarbonate buffer and incubated in the presence of [14C]methylaminoisobutyric acid with and without T3 for 15, 45 and 60 min. The hormone (10(-6) M and 10(-7) M) significantly stimulated amino acid accumulation in 6 and 13-day old rat testes but did not have any effect in neonatal and pubertal animals. T3 produced a dose-dependent hyperpolarizing effect at concentrations of 10(-6) M, 10(-5) M, 2 x 10(-5) M and 10(-4) M. We conclude that T3 induces a membrane hyperpolarization in Sertoli cells and stimulates amino acid accumulation in immature rat testes, demonstrating that the hormone has a rapid plasma membrane action.

Amino Acids↗
PubMed2001

Isolation and molecular characterization of methicillin-resistant coagulase-negative staphylococci from nasal flora of healthy humans at three community institutions in Rio de Janeiro City.

We describe the isolation and molecular characterization of methicillin-resistant coagulase-negative staphylococci (MRCNS) from the nasal flora of healthy humans from three institutions located in Rio de Janeiro City. Swabs were obtained from the nares of students attending a non-residential public school and adults from two military quarters. Isolates of staphylococci were tested for the presence of the mecA gene by hybridization with a specific probe. S. epidermidis was the most frequent MRCNS (38 of the total 45 CNS isolated). Twenty-five percent of nasal staphylococcal carriers studied were colonized with MRCNS. Pulsed-field gel electrophoresis (PFGE) of SmaI-digested genomic DNA was carried out to study the clonality of the methicillin-resistant S. epidermidis (MRSE) isolates. In addition to cross-colonization among individuals belonging to the same institution, familial cross-colonization appeared to contribute to the spread of the methicillin-resistant isolates among two inter-communicable institutions. Indeed, the wide genomic diversity among the MRSE flora suggests that the spread of the mecA gene among these isolates might also have occurred via horizontal transmission. Despite the limited number of institutions analysed, it is reasonable to conclude that our data do not represent a situation unique to the three organizations but may reflect other communities in Rio with respect to transmission of MRCNS.

Adolescent↗
PubMed2000

Adsorption of inulinases in ion-exchange columns.

The use of adsorption columns packed with ion-exchange resins for recovering, concentrating and purifying proteins is now widespread. The present work consists of a study on the dynamic behavior of adsorption columns that uses two kinds of adsorbents: a cationic and an anionic resin. A frontal analysis of the columns was performed with experimental data obtained from Fructozyme, a mixture of inulinase enzymes. The parameters of a Langmuir type of isotherm and adsorption kinetics were obtained from experimental tests in a batch system. A numerical technique based on orthogonal collocation and a fourth-order Runge-Kutta method was coupled with a nonlinear optimization method to predict the coefficients of the rate equations, which are fundamental for scale-up purposes.

Adsorption↗
PubMed1999

Developmental, neuro and immunotoxic effects of perinatal diazepam treatment in rats.

In utero exposure of rats to low dosages of diazepam (1.0-2.0 mg/kg) has been found to result in depression of the cellular and humoral immune responses during adulthood. Behavioral dysfunctions were also reported in infants from mothers with high benzodiazepine (BDZ) intake during pregnancy. The present experiment was undertaken to reconsider the potential action of diazepam during ontogeny in order to obtain further information about developmental processes using a refined methodology. Time-pregnant rats were treated subcutaneously with diazepam (2.0 mg/kg/day,: group E1) or with diazepam vehicle (group C1) from gestational day 14 to 20. Other dams (group E2) received the same BDZ dose from the 1st to the 21st day of lactation (weaning) or were not treated, remaining undisturbed in their home cages (group C2). The following results were obtained for animals perinatally treated with diazepam compared to groups C1 and C2: 1--increased time for testis descent and decreased time for vaginal opening (group E2); 2--no changes in the dates for ear end eye opening, or incisor tooth eruption (groups E1 and E2); 3--increased locomotor activity in the open-field (group E2) and/or in the plus maze (groups E1 and E2); 4--decreased levels of anxiety measured in the plus maze (groups E1 and E2); 5--decreased macrophage spreading and phagocytosis (groups E1 and E2). These results, which occurred in the absence of overt signs of maternal or fetal toxicity, demonstrate developmental, neuro- and immunotoxic effects of perinatal diazepam treatment in rats.

Animals↗
PubMed1992

Biochemical factors involved in the FSH action on amino acid transport in immature rat testes.

Testes of 15-day-old rats preincubated and incubated during different times with various doses of FSH (0.2; 2.0 and 20.0 mU/ml) in Krebs-Ringer bicarbonate (KRb) buffer increase the uptake of [14C] methylaminoisobutyric acid and [14C] aminoisobutyric acid. The basal and FSH stimulated amino acid transport occurs at absolute lower levels when the protein or glycoprotein synthesis is inhibited by cycloheximide (350 mumol/l) or tunicamycin (12 mumol/l) or when the microtubules are depolymerized with colchicine (1.2 mumol/l). However, the proportional increase of amino acid transport produced by FSH was maintained. The blockage of the voltage-dependent Ca++ channels with verapamil or the competitive inhibition of the bivalent ion channels by Co++ or Ni++ nullified the stimulatory action of FSH on the amino acid transport. Also quinine, that blocks the ATP dependent K+ channels, abolished the FSH action. It was concluded that in immature rat testes FSH stimulates amino acid transport through a mechanism involving voltage-dependent Ca++ channels and ATP-sensitive K+ channel.

Amino Acids↗
PubMed1992

Electrophysiological changes of Sertoli cells produced by the acute administration of amino acid and FSH.

Electrophysiological studies were carried out using seminiferous tubules of "Sertoli cell enriched testes" of rats irradiated in utero. Sertoli cells were inserted with glass microelectrodes in a superfusion chamber continuously perfused with KRb buffer. The topical application of FSH (4.0 mU/ml) produced a biphasic effect characterized by a rapid hyperpolarization (less than 3 s) followed by depolarization. The depolarizing effect of FSH was prolonged and potentiated in the presence of 5 mmol/l alpha-methylamino-isobutyric acid in the bath medium of the superfusion chamber. Verapamil, at a dose (250 mumol/l) that nullified the stimulatory action of FSH in the amino acid transport, suppressed the depolarizing effect of FSH. It was concluded that in immature rat testes FSH produces electrophysiological changes that mediate the stimulatory action of the amino acid transport.

Amino Acids↗
PubMed1990

Effects of caffeine on the rate of perceived exertion.

The role of caffeine in improving performance in endurance exercises is controversial and its mechanism of action is not well understood. The purpose of the present study was to evaluate the effects of caffeine on the rate of perceived exertion (RPE) by exercising athletes. Six male non-smoking runners, aged 26.8 +/- 4.9 years (mean +/- SD), who had been in training continuously for at least two years before the experiment were studied. Mean maximum oxygen consumption (VO2max) was 61.21 +/- 5.36 ml kg-1 min-1. The subjects were asked to exercise on a bicycle ergometer for 3 min each at 300 and 600 kg m min-1, after which the work load was elevated to 1200 kg m min-1 and they exercised until exhaustion. In order to evaluate the effects of caffeine, the exercise was performed twice following the ingestion of 200 ml decaffeinated coffee with and without caffeine (5 mg/kg body weight). Caffeine had no significant effect on exercise time, pulmonary ventilation, oxygen consumption, carbon dioxide extraction or exchange respiratory ratio, but the RPE was significantly lower (P less than 0.05) at the work load of 1200 kg m min-1 after the ingestion of caffeine for both trials I and II. The present results suggest that metabolic acidosis and glycogen depletion were not the main causes of exhaustion.

Adult↗
PubMed1989

Breathing pattern during pharmacological activation and blockade of the intermediate area of the ventrolateral surface of the cat medulla.

The present study analyzes the respiratory pattern of chloralose-(50-60 mg/kg, iv) anesthetized cats treated with Nembutal (NE) (30 mg/ml), glycine (GL) (200 mg/ml) or leptazol (LE) (200 mg/ml) topically applied to the intermediate area of the ventrolateral surface of the medulla oblongata in a volume of 20 microliters. Application of NE and GL produced a decrease in ventilation (approximately 24%) and tidal volume (approximately 25%) suggesting that the intermediate area facilitates respiratory drive and inhibits the inspiratory off-switch mechanism. These results are consistent with the view that intermediate area is necessary for the central chemosensitivity to CO2. The topical application of LE produced an increase in inspiration time (12.5%), expiration time (20.8%) and tidal volume (7%). The increased tidal volume caused by LE is compatible with its action as a GL antagonist.

Animals↗
PubMed1984

Progressive multifocal leukoencephalopathy in a renal transplant recipient. Increased diagnostic sensitivity of computed tomographic scanning by double-dose contrast with delayed films.

A progressive, deteriorating neurologic disorder developed in a 28-year-old white man 10 years after he successfully received a living related donor kidney transplant. An extensive neurologic evaluation was unrevealing, including normal results of computed tomographic scanning of the brain with and without contrast medium. Repeated computed tomographic scanning after a double dose of radiocontrast medium in conjunction with delayed imaging revealed multiple areas of abnormal enhancement. This technique helped to direct brain biopsy, which led to the early diagnosis of progressive multifocal leukoencephalopathy and the institution of specific therapy.

Adult↗
PubMedDate not supplied

Changes in Saccharomyces cerevisiae development induced by magnetic fields.

Saccharomyces cerevisiae cultures exposed to 110 mT and 220 mT steady magnetic fields (SMF) were studied to observe eventual induced growth alterations and changes in metabolic activity. Cell mass (biomass) growth was evaluated by light spectrometry, and metabolic alterations were estimated on the basis of the CO2 pressure produced and by the culture media pH changes, measured at the beginning and the end of the observation. The yeast strain DAUFPE-1012, cultivated in a nonaerated liquid agar Sabouraud glucose medium, was exposed to SMF generated by NdFeBr magnets. Results showed alterations induced by 220 mT SMF as an increment in cell proliferation (1.84%) and an increased CO2 production (36.1%) as compared to control groups. Furthermore, the initial-to-final pH difference in 220 mT SMF exposed cultures was higher than the 110 mT SMF and the control values. The whole acidification and the rise in CO2 production observed after 220 mT SMF exposure did not correspond to the biomass growth values, as compared to the other cultures, and was apparently provoked by a enhancement in the cellular metabolic rate. This technique becomes very promising for future biotechnological applications in fermentative processes.

Biomass↗
PubMedDate not supplied

[Glomus tumors in head and neck: assessment with magnetic resonance].

Glomus tumors originate from paranglionic tissues. In head and neck, these lesions are mainly found near carotid bifurcation, X nerve, jugular bulb or middle ear. These tumors have a low growing rate and are hypervascularized. Their histology show "nonchromaffin" cells and vascular structures involved by a fibrous matrix. MRI, CT and angiography are imaging methods used in glomus tumor. The author describe four cases of jugulo-timpanic glomus tumors studied by MRI, showing their main findings and the value of this method to detection of these lesions.

Adolescent↗