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Biomedical subjects

U Banerjee

Publications and source records attributed to U Banerjee.

106 records · Page 6Linked to original sources
PubMed1970

Microinjections of tubocurarine, leptazol, strychnine and picrotoxin into the cerebral cortex of anaesthetized cats.

1. In cats anaesthetized with intravenous chloralose, microinjections of tubocurarine, leptazol, strychnine or picrotoxin, in a volume of 1 mul, were made into the grey matter of the cerebral cortex and the electrical activity was recorded from the site of injection with the microinjection cannula which, insulated except at its tip, served as recording electrode.2. Routinely the injections were made into the gyrus splenialis or into the underlying gyrus cinguli close to the mid-line, because the injections would then most likely be in grey and not in white matter. Injected in this way all four drugs set up foci of excitation which gave rise to synchronous firing of a large number of neurones with the result that high voltage negative spikes were recorded from the microinjection cannula.3. On injection into the gyrus splenialis the threshold dose was about 0.04 mug for picrotoxin, about 0.2 mug for tubocurarine, about 5 mug for strychnine and 25 to 50 mug for leptazol. Following the injection of larger doses the spike discharge continued for a few hours after picrotoxin and tubocurarine, for over an hour after strychnine, but for a few minutes only after leptazol. On injection into the gyrus cinguli the threshold doses were slightly greater and with larger doses the spikes occurred at greater frequency but were of lower voltage than in the gyrus splenialis.4. With large doses of picrotoxin injected into the gyrus splenialis the spikes developed an after-positivity and an after-discharge which sometimes passed into a short period of fast activity.5. The foci of excitation set up by the drugs were restricted to the site of injection because on raising or lowering the microinjection cannula the spikes recorded from it quickly decreased in voltage and then disappeared. When the injections were made close to a sulcus and the microinjection cannula, on being lowered, traversed the sulcus, the spikes changed their polarity.6. The spike discharge appears to be a consistent response to the injections of the drugs into grey matter of any part of the cerebral cortex since it was also obtained on their injection into the pyriform cortex, amygdala and area retrolimbica anterior, but not on their injection into white matter or caudate nucleus, thalamus or hypothalamus.

Action Potentials↗
PubMed1968

Effect on temperature of 5-hydroxytryptamine injected into the cerebral ventricles of cats.

1. In unanaesthetized cats the effect on rectal temperature was examined of 5-HT injected through a Collison cannula chronically implanted into the left lateral ventricle. The response depended on the amount of 5-HT injected and on the solvent employed.2. An intraventricular injection of 200 mug 5-HT creatinine sulphate dissolved in 0.9% NaCl solution resulted in a long-lasting rise often interrupted initially by a transient fall in temperature.3. This fall became more prominent with larger doses of 5-HT; even more when the 5-HT was dissolved in distilled water, and then the hyperthermic effect was attenuated.4. It is concluded that intraventricular 5-HT raises rectal temperature in cats when the amount is not too large, and that a hypothermic effect when it occurs results from paralysis of cells in the anterior hypothalamus which are excited by small doses. This would be similar to the actions of acetylcholine in the perfused superior cervical ganglion of the cat, where small doses excite but large doses paralyse the ganglion cells.5. An intraventricular injection of distilled water produced a steady rise in temperature which is attributed to release of 5-HT.

Animals↗
PubMed1968

Temperature effects of reserpine injected into the cerebral ventricles of rabbits and cats.

1. In unanaesthetized rabbits and cats reserpine was injected through a chronically implanted cannula in the left lateral cerebral ventricle, and rectal temperature was recorded.2. In rabbits the reserpine (0.5-0.6 mg) caused a rise in temperature, frequent defaecation and sedation. On repeating the intraventricular injections at 24 hr intervals the rise in temperature was not obtained with the second or third injection, but defaecation and sedation still occurred. When the hyperthermic response to intraventricular reserpine had disappeared the anterior hypothalamus still responded to intraventricular noradrenaline which produced a rise in temperature.3. In cats the reserpine (0.5-0.75 mg) caused a biphasic change in temperature, i.e. an initial fall followed by a rise, frequent defaecation, and catalepsy. On repeating the intraventricular injections at 24 hr intervals the initial hypothermic phase of the temperature response was not obtained with the second or third injection, but the late rise, defaecation and catalepsy were still produced. When the hypothermic phase had disappeared the hypothalamus still responded to intraventricular noradrenaline or adrenaline which produced a fall, and to intraventricular 5-hydroxytryptamine (5-HT) which produced a rise in temperature.4. It is concluded that the rise in temperature in rabbits and the initial fall produced in cats is not due to a direct action of reserpine on the cells of the anterior hypothalamus but to noradrenaline released from adrenergic fibres ending at these cells. When these fibres are depleted of their noradrenaline by one or two injections of reserpine, these effects are not obtained because noradrenaline is no longer available to be released in sufficient amounts to raise temperature in rabbits and to lower it in cats.

Animals↗
PubMedDate not supplied

A two-step schedule for the treatment of actinomycotic mycetomas.

Actinomycotic mycetomas usually respond slowly to treatment with antibiotics. In an attempt to hasten clinical resolution, we used a 2-step regimen consisting of an intensive phase of therapy with penicillin, gentamycin and co-trimoxazole for 5-7 weeks, followed by maintenance therapy with amoxicillin and co-trimoxazole. Seven patients were treated, all of whom showed significant reduction in discharge and swelling after the intensive phase. Maintenance therapy was continued for 2-5 months after the lesions became completely inactive. Five patients completed maintenance therapy, which was given for 6-16 months (mean 10.7 months), and remained free of disease during a mean post-treatment follow-up period of 6.4 months. The other 2 patients also responded satisfactorily and continue to receive maintenance therapy. Side-effects necessitating a modification of the treatment schedule occurred in 2 patients but reversed on discontinuation of the drugs responsible. This treatment schedule produces a rapid clinical response during the initial, intensive phase and promotes compliance with the longer maintenance phase of treatment necessary to achieve a complete cure.

Actinomycosis↗
PubMedDate not supplied

Study of onychomycosis in India.

Fungal agents causing onychomycosis in an Indian population were studied in a hospital based study. It revealed that onychomycosis is more common in adult males, and that finger nails were more often affected compared with toe nails. Occupation did not seem to be related to infection. Trichophyton rubrum was the commonest fungus isolated (49.3%) followed by Candida species (23.2%). Four morphological varieties of Tr. rubrum colonies were observed but the role of a particular variety in causing chronic infection could not be ascertained.

Adolescent↗
PubMedDate not supplied

Broad spectrum herbal therapy against superficial fungal infections.

Skin disease associated with keratinized tissues in animal and human beings has been investigated. The essential oil of Eucalyptus pauciflora in vitro showed strong antifungal activity at 1.0 microl/ml against human pathogenic fungi, viz. Epidermophyton floccosum, Microsporum audouinii, M. canis, M. gypseum, M. nanum, Trichophyton mentagrophytes, T. rubrum, T. tonsurans and T. violaceum. The oil has heavy doses of inoculum potential at 1.0 microl/ml. Moreover, it did not exhibit any adverse effects on mammalian skin up to 5% concentrations. Further, we formulated the oil in the form of ointment 'BSHT' (broad spectrum herbal therapy) (1% v/v) and subjected it to topical testing on patients attending the outpatient department of M.L.N. Medical College, Allahabad. Fifty patients were selected on the basis of KOH-positive results and diagnosed as either tinea pedis, tinea corporis or tinea cruris. After the second week of treatment, all patients were KOH-negative. At the end of medication, 60% of patients recovered completely and 40% showed significant improvement from the disease. No KOH-negative cases of relapse were observed when patients were re-examined after 2 months following the end of treatment. Thus, the ointment can be exploited commercially after undergoing successful multicenter clinical trials, which are in progress.

Adult↗
PubMedDate not supplied

Humoral immune response to mutans streptococci associated with dental caries.

BACKGROUND: Mutans streptococci are important aetiological agents in dental caries and their prolonged contact with oral tissues evokes a variety of immune responses through local secretory and systemic antibodies. Patterns of such humoral responses in Indian children have not been reported and we undertook the present study to examine these. METHODS: One hundred and twenty-six children with dental caries and 55 matched controls were studied and saliva and sera collected from them. The tests on these specimens included total salivary and systemic immunoglobulins of different classes using radial immunodiffusion and Streptococcus mutans specific IgA, IgG and IgM using specifically standardized enzyme immunoassays. RESULTS: Children with caries had higher levels of IgG (1350 +/- 9.9 mg/dl; controls 1110 +/- 6.7 mg/dl) and IgA (260 +/- 1.8 mg/dl; controls 190 +/- 1 mg/dl) in the serum but their saliva had lower levels of total IgG (160 +/- 0.7 mg/dl; controls 340 +/- 2.9 mg/dl) and IgA (130 +/- 0.5 mg/dl; controls 410 +/- 3 mg/dl). IgM levels in caries children and controls were not significantly different. Higher levels of Streptococcus mutans specific IgA were detected in the saliva of 95 out of 126 (75%) children with caries compared to 13 out of 55 (22%) controls. Specific serum IgG and IgA levels were also increased in 105 and 114 children with caries, although the levels were not as high as those in saliva. Total and specific salivary and serum IgM antibodies were similar in children with caries and control subjects. CONCLUSION: The nature of the humoral immune response in Indian children with dental caries suggests that Streptococcus mutans specific salivary and serum antibodies may play a major role in pathogenesis. Our findings may have importance when devising methods for follow up and prognosis as well as for vaccination strategies.

Adolescent↗
PubMedDate not supplied

A case of prosthetic valve endocarditis caused by Cryptococcus neoformans var. neoformans.

A case of prosthetic valve endocarditis caused by Cryptococcus neoformans var. neoformans is described. The infection followed closed mitral valvotomy and insertion of a valvular prosthesis. Infection was manifested 2 weeks after the operation. The diagnosis was based on direct demonstration of the yeast with characteristic morphology in clinical material, isolation from an arterial thrombus and detection of cryptococcal antigen in the serum. The patient's infection could not be resolved despite institution of antifungal therapy.

Amphotericin B↗
PubMedDate not supplied

A comparative study of several methods for recording spontaneous motor activity in mice under drug effects.

Various existing methods of recording motor activity in animals are briefly reviewed. An electronic adaptation of an old one, the Jiggle cage, is described. The relative advantages and demerits in recording behaviour of mice under drug effects are compared with those of the traditional Jiggle cage, an electromagnetic activity counter and observational ratings.

Amphetamine↗