Biomedical subjects
Publications and source records attributed to H Singh.
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The successful management of a patient with potentially lethal intrathoracic trauma resulting from bull horn injury and involving the intrapericardial and extrapericardial portions of the right inferior pulmonary vein is described. To the best of our knowledge this particular injury has not previously been reported. Irrespective of the external appearance of the wound, hospitalization and close observation are essential. Exploration if required should be under optimal operative conditions. Popularization of disbudding and dehorning will prove an effective preventive measure.
A description is given of the pathological changes present in 8 mares which died or were euthanased in the course of an outbreak of paralysis on a Thoroughbred studfarm. In all cases the principal changes were in the central nervous system (CNS) and consisted of a severe and widespread vaculitis in the brain, cord, sheaths of nerves, capsules of ganglia and occasionally elsewhere in the body. Associated with the damage to vessel walls there was haemorrhage and exudation of plasma into the perivascular tissues. Involvement of neurones was minimal and no neuronophagia was present. Six cases had malacic foci in the brain, related to thrombosis of local arteries. Acinar necrosis in the mammary gland was present in one case. Examinations of the CNS and cerebrospinal fluid (CSF) for the presence of equid herpesvirus 1 (EHV1) or other microbial agents proved negative but EHV1 was isolated from the spleen of one mare and from the pharyngeal mucos membrane in another. The pathogenesis of this type of paralysis is discussed.
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The effects of pesticides containing either an organophosphate malathion (Cythion) or an organochloride endrin (Hexadrin) on the survival, ovarian 32P uptake and the gonadotrophic potency of the pituitary gland and serum of Heteropneustes fossilis were studied for 96 h. Hexadrin was found to be more toxic than Cythion. Reduced ovarian 32P uptake and a significantly decreased level of total gonadotrophin in the pituitary gland and serum were seen when fish were placed either in a drug concentration that had been found to kill half the fish in 96 h or in a safe concentration of Hexadrin and cythion in aquarium water. Administration of LH or homologous pituitary extract during the exposure of the fish to the pesticides increased the ovarian 32P uptake. The data suggest that these pesticides retarded gonadotrophin secretion which in turn reduced ovarian 32P uptake. However, they did not interfere with the effects of exogenous LH or pituitary extract at the dose levels tested.
Four patients with an unusual type of bone lesion are reported. The histological diagnosis in two of them was non-specific chronic inflammation and one case was diagnosed as chronic eosinophilic granuloma. On subjecting the material to culture Mycobacterium Kansasii (a photochromogen) were isolated. It is suggested that M. Kansasii are capable of producing osteoarticular lesions with a rather vague clinical and radiological picture not typical of osteoarticular tuberculosis.
In Heteropneustes fossilis testicular 32P uptake, gonadotrophin level, lipid and cholesterol contents of testis, liver and blood serum were estimated after exposing the fish to Cythion and Hexadrin at sublethal (SL) and safe concentration (SC). Four weeks of exposure to these pesticides at above concentrations during spawning phase of annual reproductive cycle, brought down effectively the testicular 32P uptake and gonadotrophic potency of the pituitary gland and blood serum. Treatment with pesticides augmented testicular lipid between 200 to 350% of control values. Liver lipid also exhibited but insignificant increase, cholesterol content of testis, liver and blood serum showed very spectacular rise in its level when compared to untreated controls. Both pesticides seem to act alike and obviously suppress gonadotrophin secretion and testicular 32P uptake. Increase in testicular and serum cholesterol is suggestive of its decreased utilization probably for steroidogenesis either due to a direct effect of pesticides or indirect on resulting from reduced output of gonadotrophin during spawning phase when in normal case both these activities were on their peaks.
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Exchange of phosphatidylinositol and phosphatidylcholine between microsomal and myelin membranes has been demonstrated. This exchange is reversible and catalyzed by soluble proteins from the brain homogenate precipitated at pH 5.1. The extent of exchange of phosphatidylinositol from microsomal membrane to myelin is dependent upon pH and temperature, with an optimum around pH 7 and at 50 degrees C. Maximum exchange was observed at approximately equal amounts of microsomal, myelin, and supernatant proteins. The extent of the catalyzed exchange increases 4- to 8-fold upon using sonicated or heat-treated myelin as an acceptor membrane. Heating of microsomal membranes results in no change. The extent of catalyzed exchange of phosphatidylcholine is less than that of the phosphatidylinositol. The exchange of other phospholipids and glycolipids between microsomal and myelin membranes cannot be demonstrated. The catalytic activity of the pH 5.1 supernatant proteins in rat brain for the exchange of phosphatidylinositol increases with age after birth and reaches a maximum around 21 days of age analogous to the process of myelination. The pH 5.1 supernatant proteins from quaking and jimpy mutant mice has normal catalytic activity.
The plasma half-life, MCR and plasma metabolite levels at various time intervals have been studied in six women after an intravenous injection of 3H-norethindrone acetate. The disappearance curve due to norethindrone acetate showed an initial rapid disappearance of 3H with an average half-life of 7.5 minutes and a subsequent slow disapperance with a half-life of 51.5 hours. Norethindrone acetate was cleared from the plasma with an average MCR of 495 L/day. Norethindrone acetate is rapidly metabolised after an intravenous injection. Norethindrone, the main metabolite, disappears from the plasma with an average half-life of 34.8 hours. Norethindrone maintains a high level compared with norethindrone acetate at all time intervals up to 24 hours and an equilibrium is reached between the two at 24 to 48 hours.
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The intra-arterial injection of 2-4 dinitrophenol, an uncoupler of oxidative phosphorylation, resulted in the production of ragged red fibers. The ultrastructure of these fibers showed intramitochondrial paracrystalline inclusions, laminar and fingerprint bodies. Antimycin A and oligomycin injection (which inhibit mitochondrial respiration) only caused swelling and disruption of the mitochondria. An increase in muscle lactic acid, decrease in ATP, glycogen and phosphocreatine was observed after the injection of all these agents. This indicates that lactic acidosis has no significant role in the pathogenesis of mitochondrial pathology. It is concluded that mitochondrial changes are a morphological expression of uncoupled but intact mitochondrial respiration.