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Biomedical subjects

C Sinha

Publications and source records attributed to C Sinha.

16 recordsLinked to original sources
PubMed1998

Acinic cell carcinoma presenting as an upper lip mass.

BACKGROUND: Acinic cell carcinoma (ACC) is a rare tumor generally involving the parotid gland and infrequently the minor salivary glands. OBJECTIVE: Clinical and histopathological characteristics of a case of ACC of the minor salivary glands, and brief review of the literature. METHODS: Routine stains with H&E, PAS, iron, and mucicarmine; immunohistochemistry with cytokeratin, CEA, S-100, and leu-M1. RESULTS: The ACC was removed by wide local excision. Histopathology revealed papillary cystic, solid, and ductal architectural features. The mucinous material within the lumina of the cystic and ductal structures was PAS and mucicarmine positive, and diastase resistant. All tested immunohistochemical reagents reacted with the epithelial cells. There were no mitoses, necrosis, cellular pleomorphism, or infiltration. CONCLUSIONS: ACC is a rare tumor of salivary glands characterized by an indolent clinical course with the potential for both local recurrence and metastatic spread when tracked for decades. Published mortality rates vary from 6 to 50%. Histopathologic features do not reliably predict biologic behavior.

Carcinoma, Acinar Cell↗
PubMed1998

Excitotoxicity and oxidative stress during inhibition of energy metabolism.

Glutamate receptor involvement and oxidative stress have both been implicated in damage to neurons due to impairment of energy metabolism. Using two different neuronal in vitro model systems, an ex vivo chick retinal preparation and dopamine neurons in mesencephalic culture, the involvement and interaction of these events as early occurring contributors to irreversible neuronal damage have been examined. Consistent with previous reports, the early acute changes in the retinal preparation, as well as irreversible loss of dopamine neurons due to inhibition of metabolism, can be prevented by blocking NMDA receptors during the time of energy inhibition. Oxidative stress was suggested to be a downstream consequence and contributor to neuronal cell loss due to either glutamate receptor overstimulation or metabolic inhibition since trapping of free radicals with the cyclic nitrone spin-trapping agent MDL 102,832 (1 mM) attenuated acute excitotoxicity in the retinal preparation or loss of mesencephalic dopamine neurons due to either metabolic inhibition by the succinate dehydrogenase inhibitor, malonate, or exposure to excitotoxins. In mesencephalic culture, malonate caused an enhanced efflux of both oxidized and reduced glutathione into the medium, a significant reduction in total reduced glutathione and a significant increase in total oxidized glutathione at time points that preceded those necessary to cause toxicity. These findings provide direct evidence for early oxidative events occurring following malonate exposure and suggest that the glutathione system is important for protecting neurons during inhibition of energy metabolism. Consistent with this, lowering of glutathione by buthionine sulfoxamine (BSO) pretreatment greatly potentiated malonate toxicity in the mesencephalic dopamine population. In contrast, BSO pretreatment did not potentiate glutamate toxicity. This latter finding indicates dissimilarities in the type of oxidative stress that is generated by the two insults and suggests that the oxidative challenge during energy inhibition is not solely a downstream consequence of glutamate receptor overstimulation.

Animals↗
PubMed1997

Ketorolac tromethamine and hemorrhage in tonsillectomy: a prospective, randomized, double-blind study.

Ketorolac tromethamine (KT) is a nonsteroidal, antiinflammatory analgesic. Its nonsedating property makes it an attractive analgesic for sleep apnea patients undergoing uvulopharyngopalatoplasty, but its antiplatelet activity makes the potential for postoperative hemorrhage a concern. A prospective, randomized, double-blind study was designed to evaluate the bleeding risk of KT using adult tonsillectomy patients as the model. Patients were randomized into two groups receiving Meperidine (MP) (controls) or KT for the first postoperative day. Posttonsillectomy bleeding rates of 7% (3/43) in the MP group and 18.9% (7/37) in the KT group were demonstrated, but this difference was not statistically significant. The number of KT doses administered had no effect on the incidence of bleeding or the number of cases requiring return to the operative suite for hemostasis. Although this study did not attain statistical significance, the trend towards increased hemorrhage with KT is worrisome. This study and other reports in the literature support the manufacturer's warning that the use of KT is contraindicated in major surgery.

Adult↗
PubMed1989

Studies of pathogenicity of the digenetic trematode Ganeo tigrinum (Mehra et Negi) for the stomach of Rana tigrina (Daudin).

Ganeo tigrinum (Mehra et Negi) was seen to be attached to the stomach wall of Rana tigrina (Daudin) by suckers drawing out mucosal plugs. The tissues lodged inside the suckers were desquamated, ulcerated and necrosed. Encapsulated flukes were seen in the submucosa. The stomach wall was completely dissolved at the site of entry of the fluke, while adjacent tissues were compressed. The gastric mucosa was mechanically compressed by the fluke. Oedema, cellular infiltrate, dilated blood vessels and congested blood capillaries were seen in the infected stomach. PAS positive and alcian blue negative mucoid substances were present in large amounts in the lumen and in small amounts in the mucosal epithelial cells of the fluke-infected stomach.

Animals↗