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Biomedical subjects

M Vaz

Publications and source records attributed to M Vaz.

At least 73 records · Page 4Linked to original sources
PubMed1993

Superficial thermal gradients during mild body cooling and its relationship to forearm blood flow.

Forearm and fingertip temperature gradients were related to simultaneously measured forearm blood flow in eleven adult subjects at rest and during a mild cold stimulus. The change in temperature gradients were converted into a percentage change of the potential capacity for heat exchange and this was found to correlate well (r = 0.73: P < 0.001) with the absolute reduction in forearm blood flow.

Adolescent↗
PubMed1993

The use of topical phenytoin as an adjunct to immobilization in the treatment of trophic leprosy ulcers.

A total of 30 leprosy patients (controls n = 16; topical phenytoin n = 14) with trophic ulcers on the feet were investigated to ascertain the efficacy of topical phenytoin powder in the healing of ulcers. The ulcers in the two groups were matched for initial size. Healing patterns were assessed by determining changes in depth and planar (surface) dimensions at weekly intervals over a three week study period. Results indicate that while immobilization of the ulcer site is effective in promoting ulcer healing, additional use of topical phenytoin accelerates the healing process. There may however be non-responders to topical phenytoin.

Administration, Topical↗
PubMed1992

Energy supplementation reverses changes in the basal metabolic rates of chronically undernourished individuals.

The objective of the present study was to examine the influence of energy supplementation and its cessation thereafter on the basal metabolic rates (BMR) of chronically undernourished individuals. Seven apparently healthy males were supplemented daily with 3.35 MJ (15 g protein, 35 g fat, 105 g carbohydrate) for 12 weeks. The average gain in body-weight was 1.9 kg (body fat, 58%; fat-free mass (FFM), 42%). The rise in BMR exceeded that accounted for by the increases in FFM during the 12 weeks of supplementation and was attributed to increases in the amount and activity of the visceral tissue as well as to an added cost of lipogenesis. At 12 weeks after cessation of the supplement, body-weights and FFM had decreased to presupplementation levels. BMR at this stage were significantly lower than at the 12th week of supplementation, when expressed per kg FFM or when adjusted for FFM using an analysis of covariance. These results suggest an increase in the metabolic efficiency during this negative energy balance period. The study demonstrates that, in the chronically undernourished, the changes in BMR are reversible and, hence, physiologically important to the process of adaptation to low-energy intakes.

Adaptation, Physiological↗
PubMed1991

Variability in cardiovascular and plasma norepinephrine responses to head-up tilt in healthy human subjects.

Eight healthy, young adult males underwent three separate, 10-min 70 degrees head-up tilts (HUT) over a period of nine days, in order to assess the intra- and inter-individual variability of cardiovascular and plasma norepinephrine (NE) responses to the manoeuvre. Cardiovascular parameters and plasma NE were measured in the basal state and at 2-min intervals during the HUT. The results indicate that: (1) the intra-individual variability is a smaller component of the total variability of both cardiovascular and plasma NE responses to HUT; (2) the variability in cardiovascular parameters is smaller than that in plasma NE levels, both basal and in response to postural stress; (3) there does not appear to be any difference in variability when expressed either as the maximal or the mean response to HUT; and (4) there does not appear to be an increase in the variability of the measured parameters over the duration of the HUT.

Adult↗
PubMed1991

Thermogenic responses to noradrenaline are unaltered following energy supplementation in chronically energy-deficient human subjects.

A group of chronically undernourished labourers underwent a period of controlled supplementary feeding (3.35 MJ per day) over a period of 12 weeks. Thermogenic responses to Noradrenaline (NA) (0.15 microgram kg-1 fat-free mass per min) were assessed (1) before supplementation (2) during the 12th week of supplementation and (3) 12-16 weeks following the cessation of supplementation. There were significant changes in anthropometric indices and basal metabolic rates (BMR) during the three stages of the study; however, these were not accompanied by significant changes in the thermogenic responses to NA.

Adult↗
PubMed1989

Repeated infusions of identical doses of norepinephrine show potentiation of metabolic responses in human subjects.

Thermogenic responses to similar doses of norepinephrine appear to be different when repeatedly administered. This hypothesis was tested by three consecutive 30-minute infusions of a fixed dose of norepinephrine separated by a rest period of one hour between infusions. There was a significant increase or potentiation of the metabolic response as measured by oxygen consumption to the third dose of norepinephrine, while the cardiovascular responses showed no change. It is therefore important to make allowances for this phenomenon when assessing intergroup differences in regulatory thermogenesis using dose-response protocols for norepinephrine administration.

Adult↗
PubMedDate not supplied

Is Helicobacter pylori infection associated with chronic idiopathic urticaria?

BACKGROUND: Chronic idiopathic urticaria (CIU) is one of the most frequent skin diseases, however its causes remain unknown in the vast majority of cases. There is increasing evidence for systemic effects of gastric Helicobacter pylori infection, which may result in extra gastrointestinal disorders. Although CIU can result from several causes, a possible relationship between chronic urticaria and Helicobacter pylori has been recently suggested. OBJECTIVE: The aim of this study is to determine the prevalence of Helicobacter pylori infection in a series of patients with CIU, and measure the effectiveness of eradication therapy on the skin disease. METHOD: We assess Helicobacter pylori infection by 13C urea breath test (UBT) in 21 CIU patients. Amoxicillin, clarithromycin, and omeprazole were given to infected patients for seven days. The results of therapy were assessed by urea breath test one month after therapy. Urticaria and gastrointestinal symptoms were assessed on enrolment and for six months after eradication. RESULTS: Prevalence of Helicobacter pylori infection was of 71.4 % (15/21). There were no differences concerning age (31.83 vs. 33.82 years) and duration of symptoms (38.40 vs. 35.38 months) in patients with respectively positive and negative UBT. Helicobacter pylori eradication rate was of 80 % (12/14). Three patients had clinical improvement with total resolution of urticaria starting immediately after eradication therapy, being able to completely withdrawn antihistamine and corticosteroids therapy without complaints. In relation to the rest of the patients, these three had smaller duration of urticaria disease (14.3 vs. 43.7 months; p = 0.038) and greater titters in the UBT results (42.39 vs. 25.81; p = 0.073). DISCUSSION: Although some authors found convincing evidence of the involvement of Helicobacter pylori as one possible cause of chronic urticaria, our results have failed to confirm the existence of this etiological association. The most remarkable finding was that those patients who had clinical remission of disease were the ones with greater UBT titters suggesting a role for the amount of colonization by Hp in the pathogenesis of urticaria disease.

Adult↗
PubMedDate not supplied

Prediction equations for handgrip strength in healthy Indian male and female subjects encompassing a wide age range.

PRIMARY OBJECTIVE: Handgrip strength is a simple index of skeletal muscle function and a functional index of nutritional status. A major lacuna in the use of handgrip strength is the limited availability of normative data. The main objective of this paper was to develop prediction equations for handgrip strength in Indians covering a wide age range. METHODS: Handgrip strength and basic anthropometric parameters were measured in 1024 healthy Indian subjects of both genders (613 males, 411 females) between the ages of 5 and 67 years. The sample was randomly divided into two sets; one set (n = 677) was used to develop the prediction equations for handgrip strength and the other (n = 347) was used to validate the equations. Each data set was further divided into two subsets (adults > 18 years, sub-adults <or= 18 years), since separate equations were developed for adults and sub-adults. Simple models that included one of the following variables: height, forearm circumference and age as well as a full model that included all three variables were developed. Gender was included in all models. RESULTS: In general, all simple models predicted handgrip strength better in sub-adults (R(2) = 0.78-0.81) as compared to adults (R(2) = 0.52-0.57). The best simple model in sub-adults was that which included age and gender (R(2) = 0.81), while for adults it was that which included forearm circumference and gender (R(2) = 0.57). The full model explained a further 3.4-6.5% of the variance in handgrip strength in sub-adults and a further 6.3-13.3% in adults. CONCLUSIONS: The simple and full model equations for handgrip strength had high predictive power in the sub-adults, while they were less predictive in adults. The equations will be of particular use in physiological studies assessing muscle strength and in clinical investigations of patients with malnutrition and neuromuscular disorders.

Adolescent↗
PubMedDate not supplied

Nimesulide-induced fixed drug eruption.

BACKGROUND: Nimesulide is a cyclooxygenase (COX) inhibitor with a high degree of selectivity to COX-2. It is a widely used and well tolerated nonsteroidal antiinflammatory drug that also has analgesic and antipyretic properties. The most frequently reported side effects concern the gastrointestinal tract. Pruritus and skin rash are the most common cutaneous adverse reactions. There are only eight cases of fixed drug eruptions due to nimesulide, described in the literature. CASE REPORT: The authors report a case of a patient with a history of antihistamine hypersensitivity who developed a bullous form of pigmented fixed drug eruption after nimesulide ingestion. Patch tests performed on residual skin lesion were positive to nimesulide, confirming that this was the culprit drug. CONCLUSIONS: Fixed drug eruptions are common cutaneous drug reactions, often misdiagnosed. A detailed anamnesis and physical examination are the key to suspect this condition.

Acetaminophen↗
PubMedDate not supplied

Central nervous system monoamine neurotransmitter turnover in primary and obesity-related human hypertension.

Recent experiments in laboratory animals have challenged the conventional view that the dominant effect of CNS noradrenergic neurons in cardiovascular control is sympathetic nervous inhibition and blood pressure reduction, describing instead sympathetic activation. We have tested whether such a stimulant effect on sympathetic outflow is also evident in human hypertension. CNS norepinephrine turnover was estimated from the combined overflow of norepinephrine, MHPG and DHPG into the internal jugular veins. Cerebral blood flow scans allowed differentiation between cortical and subcortical jugular venous drainage. In patients with pure autonomic failure, jugular overflow of norepinephrine and metabolites was not reduced, indicating brain neurons and not cerebrovascular sympathetics was the source. In healthy men, CNS norepinephrine turnover and muscle sympathetic nerve activity were directly related (p < 0.02). Administration of the ganglion blocker, trimethaphan, caused a compensatory five-fold increase in jugular overflow of MHPG. Conversely, intravenous clonidine reduced CNS norepinephrine turnover by approximately 50%, this possibly representing a mechanism of drug action. In cardiac failure patients, sympathetic nervous activation was associated with a trebling of CNS norepinephrine turnover (p < 0.01). In untreated patients with essential hypertension, the sympathetic activation present was associated with 250% higher CNS norepinephrine turnover (p < 0.01), but in subcortical brain regions only. A close and direct relation exists between brain norepinephrine turnover and human sympathetic nervous activity. CNS release of norepinephrine, presumably in the forebrain where noradrenergic neurons are sympathoexcitatory and pressor, mediates increased sympathetic nerve firing in patients with essential hypertension.

Animals↗
PubMedDate not supplied

Practices and perceptions of physical activity in urban, employed, middle-class Indians.

The aim of this study was to describe the detailed physical activity profiles of educated, employed, urban Indians and to ascertain their knowledge about the benefits of exercise, their concept of 'ideal' exercise, and the constraints in achieving it. To this end, 401 subjects (193 males, 208 females) between the ages of 25 and 58 years were studied. Women were significantly more active than men (p < 0.05), largely due to enhanced household activity (p < 0.05), which was not offset by the higher leisure time-related exercise of males (p < 0.05). Over 50 percent of subjects were aware of the benefits of exercise in preventing heart disease. The subjects' perceptions of 'ideal' exercise, based on exercise programmes they had drawn up for themselves, were adequate in terms of frequency and duration, but inadequate in intensity, when compared with the current recommendations for exercise in primary prevention of coronary heart disease. Lack of time (men 53.4%, women 68.3%) and lack of motivation (men 26.4%, women 28.4%) were the most-often cited reasons for being unable to achieve 'ideal' exercise goals. The data provides an important framework for understanding physical activity profiles of urban, educated and employed Indians on the basis of which behavioural strategies can be formulated to enhance physical activity and reduce cardiovascular risk.

Adult↗
PubMedDate not supplied

Heart rate and systolic blood pressure variability: the impact of thinness and aging in human male subjects.

BACKGROUND: Life spans are steadily increasing in developing countries where 'thinness' is widely prevalent. However, the interaction of aging and thinness has been poorly studied in terms of its physiological consequences. OBJECTIVE: To determine the impact of aging and 'thinness' (body mass index (BMI) < 18.5 kg/m2) on resting heart rate and systolic blood pressure (SBP) variability indices in the frequency domain. SUBJECTS: Ninety seven healthy male subjects were divided into two age categories; young; 18-30 yrs and old superior 60 yrs. The subjects were further divided on the basis of BMI into young, thin (n=32), young, normal BMI (BMI 18.5-25, n = 27), old, thin (n = 15) and old, normal BMI (n = 23) groups. METHODS: Cardiac autonomic nerve function was determined using heart rate variability indices in the frequency domain (low frequency, cardiac sympathetic 0.04- 0.15 Hz; high frequency, cardiac parasympathetic 0.15-0.4 Hz). Vasomotor sympathetic activity was determined from the low frequency component of SBP variability. Baroreflex sensitivity was determined from the spectral power of both RR variability and SBP variability between 0.07 to 0.14 Hz. RESULTS: Thinness was associated with a reduction in the absolute total, low and high frequency heart rate power spectrum as compared to individuals of normal BMI, but this difference was only apparent in young adults (P < 0.05) and not in older subjects. The age related decline in heart rate variability (absolute units) was apparent for subjects of both low and normal BMI (P < 0.05). There were no differences in SBP variability either with age or BMI. CONCLUSIONS: The data suggest that aging has a pronounced effect on heart rate variability, which may mask differences in heart rate variability related to thinness.

Adolescent↗