Microbial contamination of tooth brushes and their decontamination

With the dawn of the new century, dentistry has seen a new face in the fields of diagnosis, treatment and prevention. Twenty one children were asked to brush their teeth for five days. The brushes were put in Robertson's Cooked Meat broth and cultured. Growth of Streptococcus Mutans were seen. These brushes were then placed in disinfectants such as 0.2% chlorhexidine gluconate (Gp I), 1% sodium hypochlorite(Gp II) and water (Gp III) for 24 hrs and then cultured. Disappearance of growth of microorganisms was seen in Gp I and Gp II and remnants of growth seen in Gp III. It can be concluded that the use of disinfectant is a must for every individual at regular intervals.

A new physiological approach to control essential hypertension

This study was conducted on 20 male patients of Essential Hypertension (EH) in order to explore the possible role of baroreflex mechanism in the etiology of EH and also to find out whether by restoration of baroreflex sensitivity to normal level either by postural tilt stimulus on a tilt table or by the equivalent yogic postural exercise (Yogic asanas), the EH could be cured or controlled. Patients on therapeutic regime were gradually withdrawn from drug therapy, and later divided into two groups of 10 each. Group-I (age 34 +/- 1.7 years) was subjected to a 3 week course of 70 degrees head-up tilt for 30 min daily, while in group-II (age 50 +/- 3.3 years), specific yogic exercises equivalent to head-up or head-down tilt were administered for the same duration. The progressive autonomic readjustments were assessed by a battery of tests including cardiovascular responses to head up tilt, cold pressor response at 4 degrees C water (CPR), alpha index of EEG (AI), level of blood catecholamines (CA) and plasma renin activity (PRA). At the end of 3 weeks, there was a significant reduction (P < 0.001) in blood pressure in both the groups. Progressive changes in BP and HR response to tilt during 3 weeks course of tilt and yogic exercise clearly indicated gradual improvement in baroreflex sensitivity. Likewise, changes in other indices like CPR, AI, CA and PRA indicated progressive attenuation of sypatho-adrenal and renin-angiotensin activity. All these changes together with the reduction in BP strongly suggest a close link between the etiology of EH and baroreflexes on the one hand and controlling influence of the latter on sympatho-adrenal and renin-angiotensin systems on the other. It also throws light on the physiological mechanism underlying the effects of selected yogic exercises in the treatment of EH.

Cardiovascular responses to application of lower body negative pressure of male volunteers in seated position

Lower body negative pressure (LBNP) has been used to evaluate orthostatic tolerance and for studying the effects of +Gz induced physiological strain and hence has great practical significance in aerospace medicine. Cardiovascular responses in man on application to LBNP (-40 mmHg) in seated (upright) position in a specially designed LBNP chamber have been studied in eight normal healthy male volunteers between the age group of 25-36 yrs. They were subjected to -40 mmHg negative pressure in steps of -10 mmHg for a duration of 5 min each. The total duration of the experiment was 20 min. Heart rate (HR), blood pressure (BP) Cardiac output (CO) were measured and mean blood pressure (MBP) and total peripheral resistance (TPR) were computed. The results indicate a significant increase in HR (P < 0.01), SV (P < 0.01). Studies on limited number of subjects on application to LBNP (40 mmHg) in supine position have also been carried out and compared with the physiological strain induced in subjects in seated position. Study of HR, SV, CO, responses of the subjects on exposure to LBNP in seated position elicit similar response in subjects exposed to +Gz stress as reported by other workers. It is concluded that LBNP technique can be used to study the effects of +Gz induced physiological strain in man.

Personality traits and performance of military parachutist trainees

Fifty-two Indian military parachutist trainees were studied throughout the training period to investigate effects of stress in parachutist training on performance efficiency. Stress attributable to fear, anxiety, and apprehension about the inherent risk of paratrooping was studied along with physiological and biochemical changes. An attempt is made to correlate personality traits with performance efficiency. In cognitive and psychomotor tests, maximum deterioration was seen before the tower jump and aircraft jump. The deterioration was correlated with the level of anxiety and urinary catecholamine levels. Inter-correlations between anxiety, catecholamine, and blood pressure were positive, and the level of anxiety was seen to be affecting the quality of performance adversely.

An interactive image analysis system for quantitative cytology & to classify cervical cells

Introduction of computers and image analysis systems are gaining faster momentum in order to quantitate the assessment of cells for diagnosis and prognosis, and this system aims to relieve the operator from the tedium of microscopic observation and reduce operator bias and human error. This paper discusses the design and configuration of an interactive image analysis system built in the laboratory for the purpose of cell analysis and classification. The software developed to compute various textural and morphological parameters of cells on smear are briefly described. The results of the experiments carried out to classify normal and abnormal cells on cervical smear show 94 per cent success rate.

Role of xanthinol nicotinate in the revival of monkeys subjected to acute haemorrhagic shock

The therapeutic potential of xanthinol nicotinate in the revival of anaesthetised monkeys subjected to acute blood loss was investigated. The arterial pressure was lowered to 40 +/- 5 mmHg by rapid arterial bleeding and was maintained at this level for 2 h. Shed blood was then returned through infusion, to the animals. Animals alive at the end of 72 h observation period were considered as survivors. The test drug was infused 1/2 h prior to and 1/2 h, 1 h, 1 1/2 h and 2 h after the onset of oligaemic hypotension. The animals which received normal saline instead of test drug were treated as control. The physiological and biochemical parameters recorded prior to and after the onset of oligaemic hypotension were heart rate, pulse pressure, electrocardiogram, electroencephalogram (EEG), lactic acid, creatine phosphokinase, urea and glucose. The results showed tachycardia, narrowing of pulse pressure, depression of ST segment with occasional T inversion, slowing of EEG with increase in amplitude, rise in blood lactic acid, creatine phosphokinase, urea and glucose. The magnitude of these responses were proportional to the duration and severity of shock. These changes were markedly attenuated in the drug treated group. Enhancement of survival was observed in drug treated groups as compared to control. It was 10 per cent in control as against 60, 86, 71, 57 and 50 per cent in the groups which received the test drug 1/2 h prior to and 1/2 h, 1 h, 1 1/2 h and 2 h after the onset of oligaemic hypotension. It is concluded that the beneficial effect of the drug in the revival of monkeys subjected to acute haemorrhagic shock may be due to better maintenance of tissue perfusion.

Influence of thyroid hormone on the phospholipid composition of lung tissue and surfactant of rats

Thyroid hormone is an important regulator of lipid metabolism in vivo. The effect of thyroid hormone on the phospholipid composition of lung tissue and surfactant has been studied in hypothyroid and hyperthyroid rats in comparison with the control rats. Rats were made hyperthyroid by administering 1 mg of L-thyroxine/kg body weight for six days. Another group of rats was rendered hypothyroid by injecting 1 mci of Na I131 to each rat. Phosphatidyl choline, lysophosphatidyl choline, lysophosphatidyl ethanolamine, phosphatidyl ethanolamine, and sphingomyclin, were estimated by thin layer chromatography. A decrease in phospholipids in hypothyroid and an increase in the hyperthyroid rats was observed. This can be attributed to the altered thyroid activity.

Alveolar macrophages and pulmonary surfactant of altitude-raised rats

Alveolar macrophages and pulmonary surfactant were estimated in rates raised at high altitude (3500 m) and compared with control rats. Macrophages were obtained by washing the lungs with isotonic saline and counted in a haemocytometer to obtain the total number present. Proportions of two types of macrophages (precursor and mature) have been evaluated. Different fractions of phospholipids in lung lavage and lung tissue were separated by thin layer chromatography and estimated colorimetically. The results showed a reduction in the number of macrophages/g of lung with a corresponding a decrease in surfactant. The percentage of immature (precursor) macrophages was lower in high-altitude-raised rates. These changes observed in alveolar macrophages and lung surfactant could be due to an altered metabolism at high altitude.

Combined effect of hypoxia and cold on the phospholipid composition of lung surfactant in rats

The phsopholipid composition of lung tissue and lung lavage in rats exposed to acute hypoxia, chronic hypoxia, and acute and chronic hypoxia associated with cold has been estimated and compared with controls. Different fractions of phospholipids were separated by thin layer chromatography. Results showed that acute hypoxia lowered phospholipids in lung lavage but superimposition of cold lowered phospholipids both in lung tissue and lavage. In chronic hypoxia, phospholipid contents of lung tissue and lavage decreased while the addition of cold showed no further reduction in lung tissue phospholipids; on the contrary phosphatidyl choline fraction of lung lavage increased. It is concluded that the effect of hypoxia alone in lowering surfactant is related to the duration of exposure. Cold with hypoxia lowers phospholipids in the acute stage; in the chronic stage; it does not further reduce phospholipids.

Alveolar stability of altitude raised rats

On the lining of alveolar membrane of the lung presence of surfactant, a surface tension lowering agent which is a phospholipid in nature, is well established. A good correlation exists between pulmonary lecithin, the principle constituent of surfactant system and alveolar stability. The production of surface active material in the type II cells is oxygen dependent and is affected by hypoxia. The chemical and physical nature of the surfactant in the lungs of the rats raised at high altitude has been studied in comparison with that of sea level control. Eighteen male adult rats raised at high altitude (3520 m) were used. Phospholipids (Phosphatidyl Choline, Phosphatidyl ethanolamine, Lysophosphatidyl choline, Lysophosphatidyl ethanolamine and Sphingomyelin) were estimated by thin layer chromatography, stability index by Pattle's bubble technique and dynamic surface tension have also been studied to assess the surfactant activity of the lung. The results indicate that there was a decrease in lung surfactant as measured by chemical analysis. However, stability ratio measurements showed that there was very little change in the stability ratio (Sr) as the value of both groups lay in the normal range namely 0.6 to 0.9 hence the lungs of high altitude raised rats had normal alveolar stability. Surface tension values of alveolar lavage in altitude raised animals were also similar to those of normal rats. It is concluded that the rats raised at altitude show a lowering of surfactant as estimated chemically but the stability ratio is not significantly altered to indicate alveolar instability. In the altitude rats lesser quantum of surfactant is adequate to maintain alveolar stability.