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Biomedical subjects

S Lal

Publications and source records attributed to S Lal.

At least 235 records · Page 13Linked to original sources
PubMed1983

Does isopathic phenomenon occur in leprosy?

Twenty-five patients of leprosy classified according to the criteria of Ridley and Jopling (1966) were studied to verify the existence of isopathic phenomenon, using lepromin and autoclaved BCG as antigens. BCG as well as lepromin injection sites showed tuberculoid granulomas in all the cases of tuberculoid, borderline tuberculoid, mid-borderline and indeterminate leprosy. In lepromatous and borderline lepromatous cases BCG injection sites showed infiltration of foam cells containing AFB and foci of epithelioid cells, while lepromin injection sites showed infiltration of foam cells containing AFB only. These findings in the present study do not support the occurrence of isopathic phenomenon in leprosy with BCG.

BCG Vaccine↗
PubMed1982

Hypothalamic-pituitary dopaminergic function in hepatic failure in man.

The growth hormone (GH) response to apomorphine HCl (Apo) (0.75 mg sc), a dopamine (DA) receptor agonist, was assessed in healthy chronic alcoholics without cirrhosis (N = 20) and in patients with alcoholic cirrhosis both with (N = 5) and without (N = 14) hepatic encephalopathy (HE). A significant number of cirrhotic patients with (P less than 0.004) and without (P less than 0.002) HE had an impaired GH response (peak increment less than 5 ng/ml) compared with non-cirrhotic individuals. An impaired GH response was independent of the presence of HE. The magnitude of the GH response was unrelated to plasma oestrone, oestradiol, or progesterone concentrations but was significantly correlated with plasma testosterone levels (P less than 0.01). None of the patients with an abnormally low testosterone concentration showed a normal GH response. None of the subjects with HE showed an arousal response to Apo. These results suggest that DA receptor sensitivity is decreased in liver cirrhosis and that this decrease is related to inadequate circulating levels of testosterone. The occurrence of HE is independent of impaired DA function. The present study only evaluates DA function in the hypothalamic-pituitary axis and therefore may not reflect changes in other regions of brain.

Alcoholism↗
PubMed1982

Effect of domperidone on apomorphine-induced growth hormone secretion in normal men.

Domperidone, a peripheral dopamine (DA) receptor blocker which poorly crosses the blood-brain barrier and which is inactive towards dopamine-sensitive adenylate cyclase, in a dose (100 micrograms/kg) sufficient to increase serum prolactin levels at least 5-fold, decreased the growth hormone (GH) response to the DA receptor agonist, apomorphine HCI (Apo) (0.5 gm s.c.) in each of six normal men examined. The mean GH increment at 30, 45, 60 and 75 min following Apo injection, the mean individual peak increment and the mean individual GH secretion (ng min) was significantly decreased by domperidone pretreatment (p less than 0.005 -p less than 0.002). These results indicate that in man Apo stimulates GH secretion by an effect on DA receptors which are not linked to adenylate cyclase and which are situated at a locus in the hypothalamic-pituitary axis that lies outside the blood-brain barrier.

Adult↗
PubMed1982

The spatial distribution and functional properties of type I mechanoreceptor units of the sural nerve of the rabbit.

The functional characteristics and spatial arrangement of Type I mechanosensitive units found in the sural nerve of the anaesthetized rabbit have been investigated. There are approximately 108 Type I units innervating a skin area of about 59.1 cm2 supplied by the sural nerve giving an innervation density of 1.83. This innervation density of 1.83 does not vary over the skin territory innervated by the sural. The dome/fibre ratio was 2.7. The domes were found to be distributed in a dispersed but fairly regular pattern. The average nearest neighbour distance was 5.3 mm. A stimulus of 5.5 threshold units showed the existence of a small receptive field of radius 2 mm surrounding each dome; at a 3 mm radius even the largest 2 mm indentation failed to evoke a response. The response of the Type I units exhibited 4 distinct phases: (1) a dynamic phase; (2) a transient adaptive phase; (3) a highly irregular static phase; (4) an off phase. The impulse frequency/static displacement relationship was best fitted by a power function. The impulse frequency-velocity characteristic became horizontal at an average value of 15 micrometers/ms. A power function provided the best fit for this relationship. The possible physiological significance of the differences between properties of Type I receptor populations in the rabbit and cat are discussed.

Animals↗
PubMed1982

The functional properties and innervation density of type II mechanoreceptor units of the sural nerve of the rabbit.

The functional properties of Type II mechanoreceptor units of the sural nerve of the rabbit have been examined, using controlled mechanical stimuli applied to the skin. The response of Type II units exhibited 5 phases: (1) a resting spontaneous phase (2) an open phase, (3) a transient adaptive phase, (4) a regular static phase, and (5) an off phase. The impulse frequency/indentation depth relationship for the static phase was best fitted by a linear function with a slope of 0.015 and an intercept of 2.47. An almost as good fit could be obtained with a power function (exponent of 0.57 and a multiplying constant of 17.2). The impulse frequency/velocity characteristics was best fitted by a power function; it became horizontal at an average value of 5 micrometer/s. The mean threshold if Type II units was 17.2 micrometer; there was no change in response frequency once the displacement reached 1340 micrometer. There are approximately 206 Type II units innervating a skin area of 59.1 cm2, giving an innervation density of 3.42. The significance of the similarities and differences between Type II units in the rabbit compared with those in the cat are discussed.

Animals↗
PubMed1982

The responses of dorsal horn neurones to controlled mechanical stimulation of the hindlimb skin in the rabbit.

Seven types of neurones responding to mechanical stimulation of the hindlimb skin were identified in the dorsal horn of the spinal cord of the rabbit. Of the 218 units examined, 33% were activated by movement of hairs--H cells; 25% were excited by stimulation of Type I domes--on/off cells; 15.6% were spontaneously active and were excited by vertical displacement of the skin and lateral skin stretch--SPE (spontaneous excited) cells; 4.4% were spontaneously active and were inhibited by mechanical stimulation of the skin--SPI (spontaneous inhibited) cells; 5.2% were spontaneously active and responded to application of pressure--SPEP (spontaneous excited pressure) cells; 3% were spontaneously active and were excited by movement of joints--SPEJ (spontaneous excited joint) and 13.8% of neurones responded to hair movement and also to some other forms of mechanical stimulus--CM (combined mechanosensitive) cells. Of the 218 units examined, 133 were located in lamina IV and 85 in lamina V. A quantitative analysis of some of the characteristics of the on/off, SPE and SPI cells is carried out and a model of the dorsal horn system activated by Type I and Type II receptor units is proposed.

Animals↗
PubMed1982

Effect of sulpiride, an atypical neuroleptic, on apomorphine-induced growth hormone secretion.

Sulpiride (100 mg IM), an atypical neuroleptic, which does not block dopamine (DA) receptors that are linked to adenylate cyclase, abolished the growth hormone (GH) response to the DA receptor agonist, apomorphine (Apo) HCl (0.5 mg SC) in seven healthy male subjects. These results suggest that Apo increases GH secretion in man by an effect on DA receptors that are not linked to adenylate cyclase.

Adult↗
PubMed1982

Gabaergic regulation of nigrostriatal neurons: coupling of benzodiazepine and GABA receptors.

1. The GABA agonist muscimol and the benzodiazepine diazepam both decrease dopamine (DA) release in the rat nigrostriatal pathway. 2. These actions are reversed by the GABA antagonist picrotoxin and in the case of diazepam, by the benzodiazepine antagonist RO151788. 3. Our data support an inhibitory GABAergic regulation of nigrostriatal DA neurons and indicate the presence of a GABA/benzodiazepine receptor complex on these neurons.

Animals↗
PubMed1982

Drug-induced growth hormone and prolactin responses in schizophrenia research.

1. Interpretation of neuroendocrine studies in schizophrenia requires consideration of (a) the large number of variables that affect drug-induced endocrine responses (b) the effect of prior neuroleptic therapy (c) heterogeneity of schizophrenia (d) heterogeneity of receptors (e) uniqueness of the hypothalamic-pituitary axis (f) selectivity and pharmacokinetics of administered drugs. 2. Apomorphine increases growth hormone secretion by an effect on dopamine receptors that are not linked to adenylate cyclase and which are located outside the blood brain barrier. 3. Hypothalamic-pituitary histaminergic H2 and alpha-adrenergic function are unchanged in chronic schizophrenia. 4. Schizophrenic symptoms persist despite complete blockade of dopamine receptors modulating prolactin secretion. 5. Studies on dopamine receptors modulating prolactin secretion are unlikely to shed light on the pathophysiology of schizophrenia. 6. Screening for drugs which block apomorphine-induced growth hormone secretion but do not increase prolactin may provide a way of detecting anti-schizophrenic drugs which are devoid of side effects associated with hyperprolactinemia and which do not induce parkinsonism or tardive dyskinesia.

Antipsychotic Agents↗
PubMed1982

Comparison of sodium cromoglycate pressurized aerosol and powder in the treatment of asthma.

The effect of a pressurized aerosol formulation of sodium cromoglycate divided in doses of 8 mg a day was compared with that of a standard sodium cromoglycate powder (80 mg a day) in a double blind crossover trial lasting 16 weeks. No significant differences between the two formulations were detected in terms of patients' asthma severity and lung function, recorded monthly at the clinic and daily by the patients. The pressurized aerosol in a much smaller dose appears to be as effective a method as standard cromoglycate, and an alternative method of inhaling sodium cromoglycate for patients who prefer an aerosol to a dry powder formulation.

Administration, Intranasal↗
PubMed1982

Composite skin contact smears in multibacillary leprosy patients.

"Composite skin contact smears" technique was used in 20 multibacillary leprosy patients to find out the presence of AFB on their intact skin. One hundred and twenty one AFB were found in 930 sq.cm. area of skin surface examined. Seventy-five AFB were solidly staining and 46 were granular. The bacilli were found in all the sites examined. Immunofluorescent staining showed M. leprae in one out of four patients. The number of bacilli discharged from the intact skin seems adequate for the transmission of leprosy considering the large surface area of the skin and evidence in mouse experiments that multiplication of M. leprae can be obtained after inoculation of very small number of bacilli.

Female↗
PubMed1982

Epidemiology of leprosy in rural population of Pondicherry.

A village having population of 2000 in 350 families and coming under the Villianur Commune of the Union Territory of Pondicherry was subjected to a total population survey. The population examined was 92.2%. A total of 138 cases of leprosy were found in 94 families making a prevalence rate of 6.9%. There were single cases in 61 families and two to four cases in 33 families. Child rate for leprosy was 37%. The male to female ratio showed no sex predilection. Maximum percentage (30.4%) of cases belonged to maculoanaesthetic type, followed by tuberculoid (27.5%), indeterminate (19.6%), borderline (14.5%), polyneuritic (6.5%) and lepromatous (1.5%) types. Nerve involvement was more frequent in multiple skin lesion cases than in single lesion cases.

Adolescent↗