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Biomedical subjects

S S Sircar

Publications and source records attributed to S S Sircar.

13 recordsLinked to original sources
PubMed1996

Teaching nerve conduction to undergraduates: the "traveling flame" analogy revisited.

A familiar analogy to the propagation of the electric wave in a nerve lies in the burning of a cigarette. This analogy, which has persisted through several editions of popular textbooks of physiology, has never been elaborated beyond a cursory mention. In this article, the analogy is reinvoked and refined to explain the cable properties of nerve, saltatory conduction, and some other factors affecting nerve conduction velocity. Experience in lecture classes and feedback obtained through class tests indicate that the analogy, if suitably elaborated and judiciously applied, can increase the retention of the subject by the students.

Education, Medical, Undergraduate↗
PubMed1995

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.

Cohort Studies↗
PubMed1995

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.

Age of Onset↗
PubMed1994

The oxygen-carrying flask: a representational transform of the oxygen dissociation curve of hemoglobin.

The teaching of oxygen transport by hemoglobin is supported by a graphic depiction of the sigmoid O2 dissociation curve of hemoglobin. However, a reconstruction of the same curve into an alternate paradigm, the "O2-carrying flask," affords a visual demonstration of the significance of its sigmoid shape and the implications of its shifts, which should be useful in elucidating certain aspects of O2 transport to undergraduate students of physiology. This article provides a mathematical justification for the flask design.

Education, Medical, Undergraduate↗
PubMed1994

A hydrostatic model of membrane potential.

A model based on the elementary principles of hydrostatic and air pressures is proposed for classroom demonstration of some concepts related to membrane potential. The instrument comprises a system of U tubes, pressure gauges, stopcocks, and syringes. Intracellular and extracellular ionic concentrations are represented in the model by the pressure heads of fluid columns in the twin limbs of the U tubes. Membrane channels are simulated by stopcocks interposed at the bends of the U tubes. The Na(+)-K+ pump is represented by the syringes that shunt fluid from one limb of the U tube to the other. The pressure of air trapped above the fluid columns is equivalent to electrical potential.

Hydrostatic Pressure↗
PubMed1994

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.

Animals↗
PubMed1994

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.

Adolescent↗
PubMed1994

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.

Animals↗
PubMed1991

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.

Adult↗
PubMed1990

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.

Citrates↗