Correlation of autonomic indices with thyroid status.

The autonomic status in female thyroid patients was compared with healthy, age matched normal females taken as controls. The patients (29 +/- 7 years) were categorised into two groups: hyperthyroid and hypothyroid. The valsalva manoeuvre, standing to lying ratio (S/L ratio) and immediate heart rate response to standing (30:15 ratio) to assess the parasympathetic status while the galvanic skin response (GSR) was recorded to assess the sympathetic status. Statistical analysis was done using Student's t-test for comparing between the different groups and regression analysis were performed between autonomic indices and thyroid hormone levels. Although the mean values were not significantly different in hypothyroid and hyperthyroid patients, yet the correlation between autonomic function and thyroid hormone levels indicates a statistically significant difference (P-value<0.05), with the S/L ratio. The correlation was negative for log [T3] and log [T4], while it was positive for log [TSH]. This indicates that there is decreased parasympathetic activity with increased T3 and T4, which is in agreement earlier reports. The GSR, which is one of the measures of sympathetic activity, was found to be unaffected.

Task related changes in ERP auditory vs visual tasks.

P3 component of event related potentials have been studied in relaxed state of mind. Changes in P3 latency and amplitude are expected if measured after a rigorous mental exercise. The event related potentials (ERP) were measured in 20 normal male subjects aged between 18 and 22 years. ERP was recorded twice in each subject before and after the administration of a mental task. The auditory mental task comprised of repeating in reverse order string of random digits read out to the subject at a uniform speed of 1 per second. The visual task comprised reading laterally inverted type written text. Each subject had to undergo 2 sessions in separate sittings. The latency and amplitude of P300 recorded before and after the task were compared statistically using Students' unpaired t-test. There was significant increase in P3 latency following both visual and auditory tasks (auditory task: before 330 +/- 24.43 msec and after 342.9 +/- 27.66 msec, similarly visual task: before 333.2 +/- 26.66 msec and after 345.65 +/- 26.56 msec). All other ERP waves latency and amplitude changes were insignificant.

Effect of aminophylline on muscle fatigue.

The effects of two different concentrations of aminophylline, 50 microM/L and 500 microM/L on muscle fatiguability were tested using frog gastrocnemius-sciatic preparations. Two stimulation protocols, one high energy demand, and the other low energy demand were used to induce muscle fatigue. The indices of fatigue employed were (a) the decrease in peak tetanic contraction, (b) the increase in half-contraction time and (c) the increase in the contraction period in response to a high-energy-demand stimulation protocol of fatigue-induction. At the same time, it prolongs the increase in relaxation50-80 time in response to the same protocol.

Are ventilatory impairments related to early onset and long history of diabetes?

Spirometric measurements were done on 20 elderly patients (average age 49 years) of non-insulin dependent diabetes mellitus with a short history of the presenting complaints (3 months to 1 year) and moderate hyperglycaemia (blood glucose 166.42 +/- 43.58 mg/dl) and were compared with age, height and weight-matched healthy controls. The results showed significant restrictive impairments in ventilation in the diabetic group, indicating that the lung volume reductions in diabetes mellitus may not be contingent upon an early age of onset or a long duration of the disease.

Airway functions in pregnant Indian women.

The airway functions in pregnancy have been widely studied but reports obtained from Western and Indian population show divergence. While the Indian populations show significant changes in total and timed vital capacity (FVC and FEV1), the Western counterparts dismiss such changes as insignificant. Our results show insignificant alteration in airway function and support the results reported for Western population.

Effect of thyroxine on taste hedonics in rat.

1. The hedonic response to sweetness was tested in 12 thyroxine treated rats using the method of single-bottle brief-exposure to sweet (saccharin) solution. 2. Consumption of the sweet solution was significantly more following administration of thyroxine than during the control period. 3. The 1-hr consumption of saccharin solution appeared to be more sensitive to thyroxine than the 5-minute consumption.

Effect of ambient temperature changes in autonomic responses.

Effect of moderate changes in ambient temperature on autonomic activity was studied in male medical students. Autonomic function tests, i.e. Valsalva ratio, standing-to-lying ratio (S/L ratio), cold pressor response (CPR) and resting heart rate were carried out at two different ambient temperatures of 37.45 degrees +/- 0.52 degrees C and 32.54 degrees +/- 0.65 degrees C. At lower ambient temperature, there was decrease in the Valsalva ratio, increase in S/L ratio and lesser augmentation of systolic and diastolic blood pressure in CPR as compared to that at higher ambient temperature, indicating alteration in autonomic response with moderate changes in ambient temperature.

A BASIC program for teaching membrane potential.

A qualitative discourse on membrane potential, albeit simple, may be equivocal at crucial points while a purely mathematical treatise on the subject, for all its exactitude, may be incomprehensible to a student of Physiology. A quasi-quantitative approach has therefore been attempted as a compromise between clarity and exactness. A BASIC program is utilised to compute the stereotype calculations and to give instant displays of the results through figures and graphic animations.

Taste disorder in hypo and hyperthyroidism.

Gustatory responses to the basic taste substances (sweet, salty, sour and bitter) were studied in hypothyroid and hyperthyroid subjects. The intensity and hedonic responses were evaluated using "category scaling" for 7 concentrations of glucose, sodium chloride, citric acid and quinine sulphate. The intensity and hedonic values decrease in hyperthyroidism for salt and bitter solution, and sourness is perceived as more unpleasant. In hypothyroid subjects intensity and hedonic value decreases for sweetness, the pleasant responses to salt and bitter increase, though intensity perception decreases for bitter solutions.

Gustatory differences in hypothyroid and hyperthyroid tasters and non-tasters.

Gustatory differences in Phenylthiocarbamide (PTC) tasters and non-tasters were studied in hypothyroid and hyperthyroid subjects. After presenting for PTC sensitivity, gustatory responses to 7 dilutions of test solutions for glucose (sweet), sodium chloride (salt), citric acid (sour) and quinine sulphate (bitter) were studied in PTC tasters and non-tasters. The intensity and pleasantness responses for 4 basic tastes were measured on a 7-point and 6-point category scale respectively. Sixty percent of subjects of hyperthyroid and 40% of hypothyroid subjects were tasters. Hypothyroid subjects showed more gustatory differences as compared to hyperthyroids. The diminished intensity perception for sweet and bitter taste was much more prominent in non-tasters than tasters hypothyroids. The greater hedonic value for salt was largely observed among hypothyroid tasters.