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Biomedical subjects

A C Silva

Publications and source records attributed to A C Silva.

At least 73 records · Page 4Linked to original sources
PubMed1991

Determination of cadaveric antibody against HIV in vitreous humor of HIV-positive patients: potential use in corneal transplantation.

The authors suggest the determination of antibody against HIV in vitreous humor as a screening technique for AIDS carriers, specially in cases of corneal transplantation when the eye bank could make the examinations required and in cases when drawing blood after death becomes difficult. Ten eyes of patients having died of AIDS-related causes were studied and 100% of the samples tested were found to be positive. False-positive results were eliminated by the study of a group of 90 eyes of patients dead from nonrelated causes; the results were all negative. Therefore, no discrepancy was noticed between the examination of the blood and the vitreous humor. A description is made of a technique which uses a special trocar that enables the examination to be made without contamination with blood. The authors conclude that the determination of antibodies in vitreous humor is a choice to be considered as a postmortem examination because it can be easily obtained and its results are reliable.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Child health in the states of Ceará, Rio Grande do Norte and Sergipe, Brazil: description of a methodology for community diagnosis].

No reliable data are available from most Brazilian states for a number of child health indicators, such as nutritional status, breast feeding, vaccine coverage, incidence and management of infectious diseases, and coverage of antenatal and perinatal services. However a methodology has been developed for state-wide, community-based health surveys for the obtaining of such information, which was recently applied in studies of representative samples of children from the states of Ceará, Sergipe and Rio Grande do Norte in Northeastern Brazil. The present report describes the key aspects of this methodology and some of the main findings. These results point out to the need for promoting breast feeding, increasing vaccine coverage, improving diarrhoea management with oral rehydration therapy and investing in antenatal and perinatal care, as well as in growth monitoring. They also show that child survival activities are paradoxically concentrated on higher-income, lower risk children. Besides contributing to the planning and evaluation of health programs, community-based child health surveys provide baseline data against which future progress may be ascertained.

Anthropometry↗
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

Aerobic training effects on maximum oxygen consumption, lactate threshold and lactate disappearance during exercise recovery of dogs.

1. Dogs were submitted to an aerobic training schedule and its maximum oxygen consumption, lactate threshold and lactate concentration during recovery were compared among the following conditions: not trained (UT), after 1 month of training (T1), after 2 months of training (T2) and after detraining (DT). 2. Maximum oxygen consumption increased significantly in relation to UT condition only at T2 condition. The detraining reversed this alteration. 3. Lactate threshold when expressed as Vo2 or absolute work load increased significantly after aerobic training (T2) but did not present any alteration when it was expressed as % of Vo2 max. 4. The lactate decreasing during recovery did not differ between the four experimental conditions (after 10 min). 5. The latency time for the lactate concentration to reach the top values was reduced by aerobic training (T2).

Animals↗
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↗
PubMed1989

Effect of exercise training during pregnancy: maternal and fetal responses of the rat.

Pregnancy duration, offspring number, body weight gain per day, as well as offspring body and heart weights were studied in pregnant Wistar rats subjected to exercise training at relative work loads of 60, 70, 80 or 90% of maximum oxygen consumption (VO2max) (N = 6 for each group). Pregnancy duration, offspring number and heart weight of the rats subjected to exercise during pregnancy were not different from the control group not subjected to exercise training. Body weight gain per day of pregnant rats subjected to exercise was 4.64 +/- 0.21, 4.79 +/- 0.22 and 4.72 +/- 0.12 g, respectively, for work loads of 70, 80 or 90% of VO2max. This decrease of body weight gain per day was significantly different (P less than 0.05) from the control group (5.69 +/- 0.22 g). The offspring body weight decreased in the rats submitted to work loads of 70, 80 and 90% of VO2max (5.30 +/- 0.05, 5.34 +/- 0.02 and 5.24 +/- 0.01 g, respectively) by comparison to the control group value (5.73 +/- 0.07 g). These results suggest that only intense exercise could impair body weight gain in pregnant rats and their offspring.

Animals↗
PubMed1989

Oxygen consumption and ventilation during constant-load exercise in runners and cyclists.

The effect of using specialized or no specialized muscle groups on ventilatory threshold (VT) and on maintenance of steady-state oxygen consumption during long term exercise on treadmill and on cycle ergometer was studied in ten endurance runners and nine cyclists. Initially, maximum oxygen consumption (VO2max) and VT were determined. Oxygen consumption (VO2) ventilation (VE) respiratory rate (f), and blood lactate (in the beginning and at the end of exercise) were measured during exercise at constant relative loads of 60, 70, and 80% of VO2max. In the runners, both VO2max and VT (expressed as % VO2max and VO2 l/min) were greater on treadmill than on cycle ergometer and in the cyclists, VO2max was higher on cycle ergometer than on treadmill, but no differences in VT were detected between the two tests. The VO2, VE, and f drifts correlated with blood lactate level as well as with the calculated VT. The results suggest that the effect of using specialized or no specialized muscle groups on the maintenance of VO2 steadiness is achieved through training-induced changes on the level of blood lactate and, in VT.

Adult↗
PubMed1987

McArdle's disease in two generations: autosomal recessive transmission with manifesting heterozygote.

A 17-year-old boy had exercise-induced cramps and myoglobinuria. The mother had myalgia and weakness after exercise but the father was asymptomatic. Muscle biopsy was normal in the father but showed glycogen storage and absent or markedly decreased histochemical stain for phosphorylase in mother and son. Autosomal dominant McArdle's disease was considered likely, but biochemical studies showed that muscle phosphorylase activity was 0.6% of normal in the son, 20% in the mother, and 45% in the father, with corresponding decreases of cross-reacting material by immunotitration. These data suggest autosomal recessive transmission. One of the parents was clinically silent and the other was a manifesting heterozygote.

Adolescent↗
PubMed1987

Breathing pattern during exercise in myopathic subjects.

Previous studies have described a neurogenic-induced ventilatory tachypneic response during exercise. The present paper compares the breathing pattern of control and myopathic human subjects submitted to exercise. Peripheral neurogenic stimuli (PNS) at the same level of oxygen consumption should be enhanced in myopathic subjects as a consequence of muscular mass loss. Myopathic individuals showed hyperventilation (increased VeO2 and VeCO2) which was mostly due to higher respiratory frequency. The shorter respiratory cycle was due chiefly to Te reduction, since the Ti/TTOT ratio was greater in the myopathic individuals for a VO2 of 1 L. These results are in agreement with previous studies in anesthetized dogs and in unanesthetized humans in which a tachypneic mechanism associated to the relative work load was observed. These results also suggest that PNS may have a facilitatory effect upon the inspiratory off switch mechanism.

Adolescent↗
PubMed1987

Cardiorespiratory responses to exercise in patients with spinal muscular atrophy and limb-girdle dystrophy.

Maximum oxygen consumption, maximum heart rate and maximum ventilation during cycle ergometer exercise were studied in individuals with spinal muscular atrophy (N = 8) and limb-girdle dystrophy (N = 8). The limiting factors in aerobic power may be related to loss of functional muscular mass rather than to changes in the oxygen transport system. There was no correlation between VO2 max values and muscle strength as determined by a manual test of the affected muscles recruited for bicycle exercise. The results, therefore, do not support the possibility of a correlation between these indices previously proposed on the basis of clinical evidence.

Adolescent↗
PubMed1984

Maximal oxygen uptake during exercise using trained or untrained muscles.

Maximal oxygen uptake, VO2 max, was determined for cyclists, long-distance runners and non-athletes during uphill running (treadmill) and cycling (cycloergometer) to compare trained and untrained muscles. Blood lactate, maximal heart rate and maximal ventilation during work were also measured. VO2 max was higher for runners and non-athletes during exercise on the treadmill and higher for cyclists during exercise on the cycloergometer. For runners and non-athletes, maximal heart rate accompanied the increase in VO2 max, whereas similar values were obtained for cyclists on both ergometers. Maximal ventilation during work accompanied the difference in VO2 max in both groups of athletes but among non-athletes it was similar during exercise on both the cycloergometer and the treadmill. Blood lactate was similar during exercise on both ergometers for all groups. These results suggest that the quantitative effects of training on cardiovascular and respiratory functions may only be properly evaluated by using an ergometer which requires an activity similar to that usually performed by the subjects. Cycle riding may possibly induce significant and specific alterations in the muscles involved in the exercise, thus increasing peripheral O2 uptake even after stabilization of maximal cardiac output, whereas running may well induce an improvement of all factors which are responsible for aerobic work power.

Bicycling↗
PubMedDate not supplied

[Distal gastric carcinoma with duodenal invasion. Histopathologic study and review of the literature].

Gastric carcinoma with duodenal invasion is reported in 11% to 33.3% of surgical specimens. In spite of this high frequency, it is not easily recognised during the surgical proceeding or at gross examination. The study of risk factors like histological type, tumor stage and extension of duodenal invasion can be useful in establishing the best surgical approach in order to diminish the risk of local recurrence. We report 50 cases of distal gastric carcinoma in which we analysed the tumor extension in the different layers of the duodenal wall; duodenal invasion was correlated with histological type, level of infiltration in the gastric wall and presence of vascular invasion. Duodenal invasion was observed in 27 cases (54%), 17/32 of intestinal type (53%), 9/10 of diffuse type (90%) e 1/8 of non-classifiable tumours (12.5%). Diffuse type carcinoma was the most important risk factor for invasion (OR = 11; CI 95%: 1.20 to 254.16; P < 0.01). Most of the cases (21/27, 77%) were stage III or IV. The submucosal layer was the most frequent (22/27 cases, 81%) and also most extensively (8.21 +/- 9.75 mm) invaded. We conclude that the risk of duodenal invasion is higher in diffuse type tumours and in stage III or IV. Distal surgical resection should be wider in these cases and determined by frozen section biopsy specimen at the point of transection.

Carcinoma↗
PubMedDate not supplied

Studies on human anti-rabies immunization in Brazil. I--Evaluation of the 3 + 1 pre-exposure vaccination schedule under field conditions.

The currently used pre-exposure anti-rabies immunization schedule in Brazil is the one called 3+1, employing suckling mouse brain vaccine (3 doses on alternate days and the last one on day 30). Although satisfactory results were obtained in well controlled experimental groups using this immunization schedule, in our routine practice, VNA levels lower than 0.5 IU/ml are frequently found. We studied the pre-exposure 3+1 schedule under field conditions in different cities on the State of São Paulo, Brazil, under variable and sometimes adverse circumstances, such as the use of different batches of vaccine with different titers, delivered, stored and administered under local conditions. Fifty out of 256 serum samples (19.5%) showed VNA titers lower than 0.5 IU/ml, but they were not distributed homogeneously among the localities studied. While in some cities the results were completely satisfactory, in others almost 40% did not attain the minimum VNA titer required. The results presented here, considered separately, question our currently used procedures for human pre-exposure anti-rabies immunization. The reasons determining this situation are discussed.

Antibodies, Viral↗
PubMedDate not supplied

Visceral larva migrans and tropical pyomyositis: a case report.

We report a case of tropical pyomyositis in a boy who presented with a severe febrile illness associated with diffuse erythema, and swelling in many areas of the body which revealed on operation extensive necrotic areas of various muscles that required repeated débridement. The patient gave a history of contact with dogs, and an ELISA test for Toxocara canis was positive. He also presented eosinophilia and high serum IgE levels. Staphylococcus aureus was the sole bacteria isolated from the muscles affected. We suggest that tropical pyomyositis may be caused by the presence of migrating larvae of this or other parasites in the muscles. The immunologic and structural alterations caused by the larvae, in the presence of concomitant bacteremia, would favour seeding of the bacteria and the development of pyomyositis.

Adolescent↗
PubMedDate not supplied

[Disseminated cutaneous leishmaniasis due to Leishmania viannia braziliensis in the state of Maranhão, Brazil].

The authors describe a case of a patient from Barreirinhas, MA with disseminated cutaneous leishmaniasis, who presented 58 lesions spread all over his body, with many different aspects, but ulcerative lesions were predominant. They discuss the difficulty of laboratory diagnosis in the beginning of the investigation and its therapeutics implications. The parasite isolated was identified as Leishmania viannia braziliensis using monoclonal antibodies in the fluorescent antibody test. This form of the disease is different from the diffuse cutaneous leishmaniasis found in Maranhão, due to Leishmania (Leishmania) amazonensis which is responsible for most of the cases of cutaneous leishmaniasis in our state. The possible mechanisms of lesions dissemination are discussed.

Adult↗