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Biomedical subjects

K Gopal

Publications and source records attributed to K Gopal.

At least 19 recordsLinked to original sources
PubMed1990

Hypertension and myocarditis in rabbits exposed to hexachlorocyclohexane and endosulfan.

Male albino rabbits were exposed to the organochlorinated pesticides hexachlorocyclohexane (HCH) and endosulfan (2.5 and 5.0 mg/kg, ip) twice a week for 12 mo. The mean body weight of the rabbits at 12 mo was lower than that of the controls. There was rise in blood pressure and heart rate. Electrocardiograms (ECG) in both the exposed groups showed increases in PR, QT and RR intervals. Extensive myocardial damage was recorded with marked degeneration of muscle fibers vacuolization and leucocytic infiltration. Adrenals had thickened capsules and hyperplasia of cortical cells. Both pesticides produced significant increases (p less than 0.001) of 11-hydroxycortisone at all time intervals. Hypertension and myocarditis occurred in rabbits exposed to HCH and endosulfan.

Adrenal Glands↗
PubMed1989

Role of neurotransmitters in fenitrothion-induced aggressive behaviour in normal and lesioned rats.

Normal and brain-lesioned (amygdala, septal and nigral regions) rats exposed to fenitrothion (10 mg/kg) for 15 subsequent days showed elevated foot-shock fighting behaviour (septal and nigral lesioned rats). Treated animals failed to perform the rotorod test and showed decreased locomotor activity followed by convulsions. The brain-lesioned rats treated with 10 mg/kg fenitrothion showed a marked decrease in the level of norepinephrine (NE) and serotonin (5-HT).

Aggression↗
PubMed1988

Effect of repeated exposure to lindane and cadmium on lindane metabolism in rats.

The effects of daily administration of cadmium and lindane for 35 days on the metabolism of lindane in rats were investigated. The results indicate that cadmium induces a significant inhibition of lindane metabolism, since the group dosed with lindane plus cadmium had a significantly higher concentration of lindane in plasma and tissues than the group dosed with lindane alone. The inhibition in the metabolic rate of lindane is associated with the cadmium-induced alterations in the disposition of essential trace elements, Zn, Cu and Fe, in the liver.

Animals↗
PubMed1986

Endosulfan induced inhibition of 3H-5-hydroxytryptamine uptake in platelets.

Endosulfan, a chlorinated pesticide, is widely used to control various insect pests. Rats exposed to 1 mg and 3 mg endosulfan/kg for periods of 10, 30, and 60 days showed significant (P less than 0.05) inhibition of [3H]5-hydroxytryptamine (5-HT) uptake by platelet-rich plasma (PRP) in an ex vivo study. Rats treated with endosulfan (1 and 3 mg/kg) up to 60 days elucidated a marked inhibition of ADP-induced aggregatory responses of the platelets. Incubation of PRP with 10 microM and 100 microM endosulfan for 15 min at 37 degrees C also resulted in significant (P less than 0.05) inhibition of platelet aggregation in vitro. The paper discusses the use of rat blood platelets as a model for the study of neuro- and cardiovascular toxicity of endosulfan.

Animals↗
PubMed1986

Endosulfan and cholinergic (muscarinic) transmission: effect on electroencephalograms and [3H]quinuclidinyl benzilate in pigeon brain.

Single exposure of endosulfan (5 mg/kg) to pigeons (Columbia livia) caused neuronal hyperexcitability as evidenced by spike discharges of 200-500 microV in the electroencephalograms (EEG) from the telencephalon and hyperstriatum, but there was no effect on the ectostriatal area. Cholinergic (muscarinic) receptor binding study using [3H]quinuclidinyl benzilate ([3H]QNB) as a specific ligand indicated that a single exposure to 5 mg/kg of endosulfan caused a significant increase (P less than 0.05) in [3H]QNB binding to the striatal membrane. Behavioral study further indicated that a single dose of 200 micrograms/kg of oxotremorine produced a significant induction in the tremor (P less than 0.01) in endosulfan-pretreated pigeons. The results of this behavioral and biochemical study indicate the involvement of a cholinergic (muscarinic) transmitter system in endosulfan-induced neurotoxicity.

Animals↗
PubMed1985

Role of neurotransmitters in endosulfan-induced aggressive behaviour in normal and lesioned rats.

Normal and lesioned rats exposed to 3 mg/kg i.p. endosulfan for 10 subsequent days showed elevated foot-shock fighting behaviour in septal and nigral brain-lesioned animals. Increased ipsilateral circling was noticed in unilateral-nigral lesioned rats. A marked decrease in locomotor activity and no seizure pattern were recorded in rats treated with chlorpromazine (CPz). Electroencephalographic recording on the tenth day of endosulfan exposure showed high-voltage slow activity (HVSA) with occasional spindles and 5-6 Hz amplitude of 200 microV. In the treated rats an increase in the concentration of dopamine (DA) and a decrease in serotonin (5-HT) were recorded in amygdaloid, septal and nigral brain-lesioned rats.

Aggression↗
PubMed1981

The acute toxicity of endosulfan to fresh-water organisms.

A static bioassay is performed for measuring the short-term (96 h) toxicity of endosulfan to juvenile catfish Clarias batrachus, insect nymph Enallagma sp. and frog tadpoles of Rana tigrina. Median Tolerance Limit, Slope Function, Confidence Limit, and Presumable Harmless Concentration were computed. The results showed that frog tadpoles are more susceptible to endosulfan than insect nymph and catfish. Morphological changes and behavioural alterations were evaluated as symptoms of endosulfan toxicity.

Animals↗
PubMed1981

Bromocriptine therapy in acromegaly. A long-term review of 35 cases.

Bromocriptine (CB-154, Parlodel, Sandoz) was given to 35 acromegalic patients for a period of 6-36 months. Basal and post-therapy endocrine functions including estimation of serum growth hormone (GH) profile; and GH kinetics during oral glucose tolerance test, augmented insulin tolerance test and thyrotrophin releasing hormone test were determined. The pituitary tumour size was delineated by a pneumoencephalogram. The mean GH levels ranged from 14 micrograms/l to 316 micrograms/l. Bromocriptine suppressed GH values to 5 micrograms/l or less in 16 patients and less than 10 micrograms/l in a further 6 patients. In 33 patients GH values fell to 50% of the basal value or less. There was no significant GH reduction in 2 'nonresponders'. Bromocriptine did not block the stress-induced GH secretion. It did not disturb pituitary functions other than prolactin which was suppressed much earlier and was maintained with smaller doses. GH suppression on the other hand was shortlived and rebounded when the drug was omitted. It had no adverse effect on tumour size in 2 patients having suprasellar extension of the tumour. Bromocriptine improved carbohydrate tolerance and sexual function although it did not affect insulin and gonadotrophin values. It seems reasonable to offer a trial of bromocriptine in all patients with acromegaly where therapy is deemed necessary as it is well tolerated, has insignificant side effects and no adverse drug interactions. Its high cost and prolonged course are obvious disadvantages. Caution should be exercised in cases with suprasellar extension and visual field involvement.

Acromegaly↗
PubMed1981

Pituitary apoplexy (spontaneous pituitary necrosis).

Pituitary apoplexy or spontaneous pituitary necrosis is an ill-understood clinical syndrome. It may occur as a neurological emergency requiring urgent interference in a patient with a known pituitary dysfunction or it may be responsible for drawing attention to an as yet unrecognized pituitary pathology. It has a bizarre clinical profile and an unpredictable neurological and endocrine course. Patients may die at once or may recover with or without endocrine/neurological deficit. Six cases of pituitary apoplexy with varied clinical presentation are cited.

Adenoma, Chromophobe↗
PubMed1980

Effect of endosulfan of bioelectrical activity of brain in rats.

Bioelectrical activity of rat brain was studied after administration of endosulfan (5 mg/kg, ip) for 10 days. The pesticide produced rhythmic bursts of spikes and waves of seizure pattern that started 25-30 minutes after dosing and persisted for 60-minutes. The clonic convulsions were more marked over the head region and were mainly localized in the upper extremities. Histopathologic examination of the liver showed congestion of the central veins and its adjacent sinusoids. Concentration of the compound in brain parallelled the electrical activity.

Animals↗