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Biomedical subjects

B K Maini

Publications and source records attributed to B K Maini.

At least 19 recordsLinked to original sources
PubMed1990

Comparison of effects of naloxone and catecholamines on acid-base balance in canine hemorrhagic shock.

The present study was conducted to compare the effect of naloxone, an opiate receptor antagonist, with catecholamines on acid-base status and survival in dogs subjected to hemorrhagic shock. Arterial lactic acid concentration which had increased during hemorrhage, decreased significantly (P less than 0.05) in naloxone treated animals but increased further in catecholamine treated dogs. Blood bicarbonate concentration and PCO2 which had markedly decreased 1 hr after hemorrhage recovered significantly (P less than 0.05) in naloxone group of animals. On the other hand bicarbonate and pH declined further in noradrenaline group and remained unchanged in dopamine group. These results as well as better survival rate observed in naloxone treated animals suggest the superiority of naloxone over dopamine and noradrenaline, as an adjunct to blood transfusion in the treatment of hemorrhagic shock.

Acid-Base Equilibrium↗
PubMed1989

Long latency cutaneous reflex effect on H-reflex recovery in hemiplegics and paraplegics: a longitudinal study for the assessment of motor function.

H-reflex recovery by twin pulses was recorded serially in 10 paraplegics for 5 months and in 23 hemiplegics for 2 months after the lesion. Fifty-one normal subjects acted as controls. The effect of cutaneous tactile stimulation was also studied simultaneously by applying electrical stimuli synchronized with twin pulses to the skin over the lateral border of small toe. In paraplegics, the H-reflex recovery curves recorded serially showed a highly depressed pattern during the first two weeks, an almost normal pattern during the second and third months and a significantly elevated pattern during the fourth and fifth months. Whereas cutaneous stimulation in control subjects produced a highly significant late inhibition of H-reflex recovery between 600 ms and 600 ms, in paraplegics it failed to produce any significant effect, except in two, who besides having a normal H-reflex recovery curve even during the first week, showed a substantial amount of cutaneous inhibition of H-reflex recovery, 4 months after the lesion. A highly depressed pattern of H-reflex recovery was observed on the affected side of the majority of hemiplegics during the first week after the lesion, many of them showing similar pattern on the "unaffected side" also. The serial study showed very good improvement in all hemiplegics both in terms of H-reflex recovery pattern and the amount of cutaneous inhibition. The observations in present study suggest preservation and/or restoration of supraspinal influences in many hemiplegics and in at least two paraplegics. The study also shows that a serial recording of H-reflex recovery curve and the amount of cutaneous reflex effect on it, is a very sensitive method of assessing the supraspinal influences on the spinal motoneurones and so can be of immense help in the diagnosis and prognosis in hemiplegics and paraplegics.

Female↗
PubMed1989

Lithium chloride SCN injection alters the circadian rhythm of food intake.

Effect of lithium injections through chronically implanted cannulae into the bilateral suprachiasmatic nuclei (SCN) on the circadian rhythm of food intake was investigated in the rat. It was observed that the circadian rhythm was disrupted by injections of lithium at the beginning of the light as well as the dark phase of the LD cycle. In either case the percentage of the food consumed during the 12-hr light period increased while that during the dark period decreased without any significant change in the total daily intake. Disruptions in the circadian rhythm of food intake failed to show any dose-response relation. Injections of saline into the SCN or lithium into the nearby SCN area did not produce a disruption of the circadian rhythm of food intake.

Animals↗
PubMed1988

Long latency inhibition of H-reflex recovery by cutaneous tactile stimulation in man: a cutaneous transcortical reflex.

The effect of cutaneous tactile stimulation on motoneuron excitability was studied in 20 normal subjects and in patients of hemiplegia (n = 14) and paraplegia (n = 15) by plotting H-reflex recovery curves during application of twin pulses alone ("basal" H-reflex recovery curve), and twin pulses synchronized with electrical stimuli evoking tactile sensation in skin over the lateral border of the small toe. The "basal" H-reflex recovery curves from normal subjects showed a significant lateral asymmetry of motoneuron excitability, with an even distribution of subjects showing greater excitability on the left and right sides. However, there was no relation between handedness and the side with greater excitability. The cutaneous stimulation produced a highly significant inhibition of the H-reflex recovery between 600 and 6000 ms, with the maximum inhibition recorded at 1000 and 2000 ms, at which time even a complete inhibition of the test H-reflex was observed in some instances. The effect of cutaneous stimulation before 600 ms was statistically insignificant. The amount of cutaneous inhibition of H-reflex recovery showed a lateral asymmetry. The side with greater motoneuron excitability showed more cutaneous inhibition of the H-reflex recovery. A comparison of the H-reflex recovery at higher frequencies of cutaneous stimulation with that at basal frequency showed a slight but statistically insignificant difference in the amount of cutaneous inhibition of the H-reflex recovery. In hemiplegics, the "basal" H-reflex recovery curves showed greater motoneuron excitability on the affected side as compared to those of the unaffected side or controls, with the late inhibitory phase being completely obliterated. A similar pattern was also observed in paraplegics. Significantly, the lateral asymmetry of motoneuron excitability observed in the control group was absent in paraplegics. The cutaneous stimulation failed to produce any significant effect on the H-reflex recovery curves either in the affected side of hemiplegics or in both sides of paraplegics. The significant long latency inhibition of the H-reflex recovery curve produced by cutaneous tactile stimulation is a new finding.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1987

Suprachiasmatic injection of a vasopressin antagonist modifies the circadian rhythm of food intake.

To study the effect on the circadian feeding rhythm, injections of AVP and its antagonist were made into the suprachiasmatic nuclei (SCN) of rats after implanting cannulae into the bilateral SCN. Injections of arginine vasopressin (AVP) antagonist at the beginning of the light and dark phases disrupted the circadian rhythm of food intake while injections of AVP during the beginning of the light or dark phase did not disrupt the circadian rhythm. It may be concluded that endogenous vasopressin has a modulatory role in the mediation of the circadian feeding rhythm at SCN.

Animals↗
PubMedDate not supplied

Pulmonary diffusion capacity for Co at varying alveolar oxygen tensions and different alveolar volumes.

In six healthy nonsmoker volunteers pulmonary diffusion capacity for Co (DLCO) was determined by single breath holding technique. Multiple measurements of DLCO were taken with PAO2 from 70 to 610 mm Hg, out of which at least 10 tests were performed between 100 to 140 mm Hg. A wide and non uniform inverse relationship was found between DLCO and PAO2 from 70 to 610 mm Hg. In narrow range of 100-140 mm Hg, a highly significant linear negative correlation was found. To find out corrected DLCO at PAO2 120 mm Hg, expressed as DLCO120, a correction factor of 0.45% for each mm Hg change in PAO2 should be applied to measured DLCO inversely. By regulating inspiratory volume, DLCO was studied at different alveolar volumes and there was a direct positive correlation between them. DLCO should be measured at maximum alveolar volume, as with one percent fall in VA there is 0.69% decrease in DLCO. This new method of expressing DLCO as DLCO120 at maximal effective alveolar volume will be more useful in studying the effects of factors affecting DLCO and for interlaboratory comparison.

Adult↗
PubMedDate not supplied

Amygdalar injections of vasopressin and its antagonist do not disrupt the circadian rhythm of food and water intake in the rat.

There is an indication that areas of the brain other than the suprachiasmatic nuclei (SCN), the known neural circadian pacemaker, are involved in the control of circadian rhythms. The present study investigated the role of amygdala in the circadian rhythms of food and water intake. Vasopressin and its antagonist d(CH2)5Tyr(Me)AVP were injected into the amygdala bilaterally through chronically implanted stainless steel cannulae. The results of the study have shown that neither vasopressin nor its antagonist d(CH2)5Tyr(Me)AVP alters the circadian rhythm of food and water intake thereby showing that vasopressinergic neurons/projections to amygdala are not involved in the control of circadian rhythms of food and water intake and amygdala is not likely to be an additional oscillator.

Amygdala↗