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Biomedical subjects

S Desai

Publications and source records attributed to S Desai.

At least 145 records · Page 8Linked to original sources
PubMed1992

Value of acute-phase angiography in the detection of vascular injuries caused by gunshot wounds to the head: analysis of 12 cases.

A study of the angiographic findings in consecutive civilian patients with cranial gunshot wounds examined in the acute stage has not been done. Most prior clinical studies have evaluated the findings in survivors in the subacute or chronic stages and have often been of war-time casualties. We determined the clinicoradiologic features of six cases of posttraumatic intracranial aneurysm, vascular occlusion, or arteriovenous fistula caused by penetrating missiles among 12 civilian patients who were examined in the acute posttraumatic stage (within 48 hr of injury) during a 1-year period. Three internal carotid/vertebral artery aneurysms, one external carotid artery aneurysm, one combined aneurysm/arteriovenous fistula of the vertebrobasilar circulation, and one cerebral venous occlusion were identified. The 50% overall prevalence of major vascular lesions in this series of civilian patients with penetrating missile injuries examined in the acute stage suggests these injuries are more common than previously suspected. It may indicate that selective cerebral angiography should be considered in the evaluation of the cranial vascular system of such persons.

Cerebral Angiography↗
PubMed1991

Duration of the preclinical phase of chronic myelogenous leukemia: a case report.

The molecular events that allow for clonal expansion of the malignant population in chronic myelogenous leukemia (CML) are poorly understood. Recent experiments in transgenic mice suggest a close temporal relationship between expression of the aberrant protein and manifestation of a hematologic neoplasm that resembles CML; tracing the same phenomenon in humans has not been possible. We studied a patient who underwent autologous bone marrow harvest after completion of chemotherapy and radiation therapy for advanced stage Hodgkin's disease. At the time of harvest his peripheral blood counts and bone marrow were morphologically normal. Sixteen months later he developed the clinical manifestations of CML. Detailed molecular evaluation of the harvested marrow showed that a small number of cells contained the Philadelphia chromosome. The time interval required for expansion of the malignant clone, as suggested by this particular patient, was at least 16 months although it is recognized that this figure may be variable.

Adult↗
PubMed1991

Primary lymphoma of bone: a clinicopathologic study of 25 cases reported over 10 years.

Twenty-five cases of primary lymphoma of bone (PLB) reported over a 10-year period were reviewed. The presenting symptom was related to involvement of a single bone with or without regional nodal disease. None showed dissemination of lymphoma in the subsequent six months. Patients affected were 7-65 years of age. An equal predilection for the axial and appendicular skeleton was noted. Histologically, the commonest subtype was diffuse histiocytic lymphoma (DHL, 17 cases), whereas four were poorly differentiated lymphocytic (PDL) type and another four were unclassifiable. Follow-up was available in 18 out of 25 patients for periods ranging from 7 months to 8 years. On clinicopathologic correlation we found that 75% of disease-free patients had a DHL whereas 60% of those alive with disease had a PDL. This study reiterates the view that PLB has a good prognosis and the DHL subtype is especially amenable to complete eradication.

Adolescent↗
PubMed1991

Two unusual cases of pneumatosis coli.

We present two patients with pneumatosis coli. The first patient demonstrates the variable distribution of gas cysts prior to spontaneous resolution. The second case presented with colonic obstruction due to gas cysts at the recto-sigmoid junction.

Barium Sulfate↗
PubMed1991

Antigen-induced mediator release in primates.

We examined the release of bronchoactive mediators into the airways of allergic primates during the acute response to specific antigen inhalation. Twelve adult male cynomolgus monkeys (Macaca fascicularis) with a naturally occurring respiratory sensitivity to inhaled Ascaris suum extract were anesthetized and intubated for each study. Respiratory system resistance (Rrs) and dynamic lung compliance (CLdyn) were measured before and after antigen inhalation, and the release of mediators into the airways was assessed by bronchoalveolar lavage (BAL). BAL samples were concentrated approximately 5-fold before quantitation of LTC4 and PGD2 by RP-HPLC and radioimmunoassay and histamine by a fluorometric assay. Antigen inhalation resulted in a 40-fold increase in BAL levels of i-LTC4 (1.5 +/- 0.7 to 41.6 +/- 12.7 ng, p less than 0.01), a 10-fold increase in i-PGD2 (2.4 +/- 0.9 to 25.9 +/- 5.5 ng, p less than 0.01), and a 20-fold increase in BAL histamine (1.0 +/- 1.5 to 21.4 +/- 2.3 micrograms, p less than 0.01). Dexamethasone (n = 7) inhibited the antigen-induced increase in BAL i-LTC4 (71 +/- 6%, p less than 0.01) and i-PGD2 (52 +/- 8%, p less than 0.05) while weakly inhibiting histamine release (43 +/- 10%). Indomethacin (n = 7) had a variable effect on i-LTC4 levels (6 +/- 51%), strongly inhibited i-PGD2 (88 +/- 9%, p less than 0.01), and had no effect on histamine release (25 +/- 8%). Pretreatment with iodoxamide tromethamine significantly blocked the release of each mediator, but mepyramine, an H1 antagonist, had no effect on mediator release.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1991

The effects of a 5-lipoxygenase inhibitor on antigen-induced mediator release, late-phase bronchoconstriction and cellular infiltrates in primates.

Inhaled BI-L-239 significantly inhibited i-LTC4 generation, late-phase bronchoconstriction and the influx of neutrophils into the lungs. We conclude that leukotriene generation and release within the lungs, following allergen exposure, in part mediate altered lung function and contribute to the development of airway inflammation. As such, treatment with a selective 5-lipoxygenase inhibitor may aid in the treatment of bronchial asthma and other allergic diseases.

Administration, Intranasal↗
PubMed1991

Acid-induced death in neurons and glia.

Lactic acidosis has been proposed to be one factor promoting cell death following cerebral ischemia. We have previously demonstrated that cultured neurons and glial are killed by relatively brief (10 min) exposure to acidic solutions of pH less than 5 (Goldman et al., 1989). In the present series of experiments, we investigated the relationship between changes in intracellular pH (pHi) and cellular viability. pHi was measured using fluorescent pH probes and was manipulated by changing extracellular pH (pHe). Homeostatic mechanisms regulating pHi in neurons and glia were quickly overwhelmed: neither neurons nor glial cells were able to maintain baseline pHi when incubated at pHe below 6.8. Neuronal and glial death was a function of both the degree and the duration of intracellular acidification, such that the LD50 following timed exposure to HCl increased from pH, 3.5 for 10-min acid incubations to pHi 5.9 for 2-hr exposures and pHi 6.5 for 6-hr exposures. Replacement of HCl with lactic acid raised the LD50 to pHi 4.5 for 10-min acid exposures, but did not change the LD50 for longer exposures: pHi measurements concurrent with extracellular acidification suggested that the greater cytotoxicity of lactic acid relative to that of HCl was caused by the more rapid intracellular acidification associated with lactic acid. The onset of death after exposure to moderately acidic solutions was delayed in some cells, such that death of the entire cell population became evident only 48 hr after acid exposure. During this latency period, cellular viability indices and ATP levels fell in parallel.(ABSTRACT TRUNCATED AT 250 WORDS)

Acids↗
PubMed1990

Dicarboxy-dichlorofluorescein: a new fluorescent probe for measuring acidic intracellular pH.

Derivatives of fluorescein sensitive to pH are extensively utilized for the determination of intracellular pH (pHi). Available dyes have pKa values of approximately 7.0, and are not well suited for measuring acidic pHi. We examined the fluorescein derivative, 5 (and 6)-carboxy-2',7'-dichlorofluorescein (CDCF) for its potential in the microspectrofluorometric measurement of pHi during acidic conditions. CDCF showed intense fluorescence and pH sensitivity near its "effective" pKa value of 4.2, using a 495/440 nm dual excitation wave-length ratio method. Protein interactions caused fluorescence ratio deviations which were most pronounced at the extremes of pH, whereas calcium and magnesium concentrations had little effect on the fluorescent ratio intensity. Intracellular calibration performed using nigericin in the presence of high potassium eliminated the need to correct for protein interactions, and the ratio method minimized any variations due to dye concentration differences or instrument fluctuation. Intracellular retention of the dye was high, and 95% of the initial signal remained after 1 h. Fluorescence bleaching was 14.5% after 1 h of continuous excitation and cell survival was not affected by dye loading. We conclude that CDCF is an excellent intracellular pH indicator in the pH range of 4-5.

Acids↗
PubMed1990

Ultrastructure of the pituitary intermediate lobe in aging rats.

The pituitary intermediate lobe, a source of pro-opiomelanocortin (POMC) peptides, was examined with light and electron microscopic techniques in Sprague-Dawley rats aged 5-18 months and Zucker rats aged 18 months. Cysts were common in the intermediate lobe in the Zucker animals, a finding also noted in human pituitary glands by other investigations. The nuclear envelopes were often indented in cells of aging rats, while those of young animals were generally smooth. Lipid droplets and lysosomes, rarely seen in tissue from young animals, were frequently observed in endocrine cells of older rats. Most cells had an abundance of secretory granules, suggestive of enhanced storage of peptides in the cytoplasm. Nerve terminals which were present among endocrine cells contained myelin figures in some of the old rats, and may indicate degenerative changes, while other terminals appeared normal. These morphologic findings suggest that the aging phenomena in intermediate lobe tissue have characteristics in common with nervous tissue, and may also reflect a diminished inhibitory neuroregulation.

Aging↗
PubMed1990

Stress-induced peptide release from rat intermediate pituitary. An ultrastructural analysis.

We tested the hypothesis that acute restraint stress results in ultrastructural evidence for enhanced release of alpha-melanocyte-stimulating hormone (alpha-MSH) and beta-endorphin from the intermediate lobe (IL) of the rat pituitary. Measurements of plasma alpha-MSH- and beta-endorphin-immunoreactivity (ir) were used to confirm ultrastructural findings. Plasma alpha-MSH-ir was elevated after 20 and 30 min of restraint while plasma beta-endorphin-ir peaked 10 min after the onset of restraint. Ultrastructural analysis revealed a decrease in the content of secretory granules within IL cells of stressed rats. Analysis of Golgi-related immature secretory granules in IL cells indicated that new peptide synthesis was not enhanced after 30 min of restraint. These results confirm previous studies showing an elevation of plasma beta-endorphin and alpha-MSH-ir during acute restraint. Furthermore, these results indicate that quantitative analysis at the ultrastructural level can be used to assess peptide release from IL secretory cells during stress.

Animals↗
PubMed1990

Discrimination between HIV-1 and HIV-2-seropositive individuals using mouse monoclonal antibodies directed to HIV transmembrane proteins.

Mouse monoclonal antibodies directed against the transmembrane proteins of HIV-1 or HIV-2 provided site-directed, unambiguous discrimination between HIV-1 and HIV-2 antibody-positive sera, when employed in immunoassays as competitive probes against serum antibodies. These monoclonal antibodies mapped to epitopes outside of the well-characterized immunodominant regions (IDR) of the transmembrane proteins. The monoclonal competitive immunoassay was a superior method for discrimination compared with immunoprecipitation of metabolically radiolabeled HIV envelope glycoproteins, Western blot against viral envelope glycoproteins, or noncompetitive enzyme immunoassays employing HIV recombinant transmembrane proteins or synthetic IDR peptides as serological targets. The monoclonal competitive assay was not affected by antigenic cross reactivity or nonspecific reactivity exhibited by selected serum samples toward envelope proteins or peptides, respectively. Results of the monoclonal competitive immunoassay were supported by results of a peptide inhibition assay employing free IDR peptides in competition with IDR peptides on a solid support for binding of serum antibody. IDR peptide inhibition clearly demonstrated non-cross-reactive antigenic specificity of sera toward either the HIV-1 IDR or the HIV-2 IDR. The monoclonal competitive assay also identified samples containing antibody to both HIV-1 and HIV-2 transmembrane proteins. Analysis of these samples by IDR peptide inhibition indicated they contained two distinct, non-cross-reactive populations of antibodies, one directed to the HIV-1 IDR and the other directed to the HIV-2 IDR.

AIDS Serodiagnosis↗
PubMed1990

Neuralgic amyotrophy: a long term follow-up of four cases.

Neuralgic amyotrophy or brachial plexus neuralgia is a condition of uncertain etiology. It needs to be differentiated from the usual brachial plexus injuries. Nerves outside the plexus especially the spinal accessory nerve are involved. Neuralgia is also a feature. Four cases were followed-up in detail over a period of two years. The condition usually resolves almost completely on its own.

Adolescent↗
PubMed1989

Pharmacological comparison of active and passive experimental allergic encephalomyelitis in the rat.

Models of actively induced and passively transferred experimental allergic encephalomyelitis (EAE) have been compared in the rat. The time of disease onset, severity of clinical symptoms and percent incidence were compared and assessed for their suitability for evaluation of immunosuppressive agents. The passive EAE model had an earlier disease onset (6 +/- 0.1 days) and 100% of the cell recipients (n = 45) developed severe clinical symptoms, including paralysis of the tail and hind limbs. In contrast, the active EAE model had a mean disease onset day of 13 +/- 0.1 and only 53% of the induced rats (n = 85) developed EAE clinical symptoms which were variable. The average symptom score in both models was inhibited by dexamethasone (1 mg/kg/day p.o.; day 0 to 3), methotrexate (3 mg/kg i.p. single dose; day 1) and cyclosporin A (30 mg/kg/day p.o.; day 0 to 7). The above study indicates that the passive EAE model is more advantageous for pharmacologic evaluation of immunosuppressive agents.

Animals↗
PubMed1989

Subungual keratoacanthoma in the hand.

A subungual keratoacanthoma of the thumb with a 5-year follow-up is reported. Recurrence after initial curettage necessitated amputation of the terminal phalanx as definitive treatment. The 22 subungual keratoacanthomas of the hand reported in the literature are reviewed. Although conservative treatment sparing the digit in the form of excision and curettage is recommended as the initial treatment of choice, this uncommon benign, but aggressive, lesion of the nail bed may require amputation of the involved phalanx as definitive treatment.

Amputation, Surgical↗
PubMed1989

Experience with the Merck small bowel enema tube.

We describe our experience using the Merck 10 French small bowel enema tube in 50 patients. Small bowel intubation was quick and easy to perform, and the tube was well tolerated by our patients. Kinking of the Merck tube was correctable, but prolonged the examination. The examination had to be abandoned in 6% of cases due to retrograde movement of the tube back into the stomach.

Adolescent↗