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Biomedical subjects

S Sharma

Publications and source records attributed to S Sharma.

At least 667 records · Page 37Linked to original sources
PubMed1997

Central administration of the neurotensin receptor antagonist, SR48692, modulates diurnal and stress-related hypothalamic-pituitary-adrenal activity.

Previous studies in our laboratory suggest that neurotensin (NT) acts centrally to modulate adrenocorticotropin hormone (ACTH) and corticosterone release. In the present studies, we examined hypothalamic-pituitary-adrenal (HPA) function under basal conditions and during restraint stress following central administration of the highly specific NT receptor antagonist, SR48692. Chronic delivery of SR48692 to the paraventricular nucleus (PVN) of the hypothalamus via indwelling central cannulae attenuated both the diurnal- and stress-induced elevations in HPA activity. Thus, SR48692 decreased the diurnal increase in plasma ACTH and corticosterone during the evening phase of the cycle, but did not affect morning levels. Restraint-induced increases in plasma ACTH and corticosterone levels were also significantly reduced in the SR48692-implanted animals. This suggests that the inhibitory effects of SR48692 were restricted to periods of stimulated HPA activity. A decrease in corticotropin-releasing hormone (CRH)-like immunoreactivity was observed within the PVN following chronic SR48692, and parallel decreases in CRH-like immunoreactivity were observed within the external zone of the median eminence. These findings suggest that endogenous NT serves to increase HPA activity during periods of enhanced stimulation.

Animals↗
PubMed1997

Pityriasis rubra pilaris as an initial presentation of hepatocellular carcinoma.

Pityriasis rubra pilaris (PRP) is a rare skin condition that is of unknown etiology. We present an unusual case of a patient with PRP as the sole initial manifestation of hepatocellular cancer. The course of the patient's illness and management of this case is discussed. Possible reasons for this association are presented.

Administration, Oral↗
PubMed1997

Stress-induced declarative memory impairment in healthy elderly subjects: relationship to cortisol reactivity.

A group of 14 healthy elderly subjects was submitted to a nonstressful (attentional task) and a stressful (public speaking task) condition. Declarative (conscious recollection of learned information) and nondeclarative (retrieved information without conscious or explicit access) memory as well as salivary cortisol levels were measured before and after each condition. The results showed that the stressful condition significantly decreased declarative memory performance, whereas the nonstressful condition did not. Nondeclarative memory performance was not affected by either condition. Further analyses separating the subjects into responders and nonresponders in terms of stress-induced cortisol changes revealed a very different pattern of cortisol secretion and declarative memory performance in both populations. We showed that the responders presented increased cortisol levels 60 min before the actual stressor, whereas the nonresponders presented increased cortisol levels 25 min before the actual stressor. Although the responders did not differ from the nonresponders in declarative memory performance before and after the nonstressful condition, they presented a lower declarative memory performance when measured before and after the stressful condition. The early increase in cortisol levels observed in the responder group suggests that the anticipation of the stress, rather than the actual stressor per se, may have played a more significant role in the stress-induced declarative memory deficits observed in this subgroup. Together, these results show that the cortisol response to anticipation of stress and/or to stress in the elderly specifically affects those memory functions that are dependent on hippocampal activity. They also suggest that an altered cortisol responsivity to acute and/or chronic stress, with its detrimental effects on memory, could be an important factor explaining the genesis of memory deficits in aged populations.

Aged↗
PubMed1997

A randomized trial of empyema therapy.

STUDY OBJECTIVES: To determine the optimal treatment of empyema thoracis (within the fibrinopurulent phase of illness) comparing pleural drainage and fibrinolytic therapy vs video-assisted thoracoscopic surgery (VATS), with regard to efficacy and duration of hospitalization. DESIGN: Twenty patients with confirmed parapneumonic empyema thoracis were randomized to chest tube pleural drainage plus streptokinase (CT-SK) vs VATS. SETTING: University-based teaching hospital providing for Dallas County. PATIENTS AND METHODS: Equivalent groups of patients with parapneumonic empyema thoracis were randomized to receive either of two therapies: CT-SK (n=9) or VATS (n=11). Outcomes analysis with respect to treatment efficacy, hospital duration, chest tube duration, hospital costs, and need for subsequent procedures was performed. RESULTS: Each group suffered one mortality (p=not significant). When compared with the CT-SK group, the VATS group had a significantly higher primary treatment success [10/11, 91% vs 4/9, 44%; p<0.05 Fisher's Exact Test], lower chest tube duration (5.8+/-1.1 vs 9.8+/-1.3 days; p=0.03), and lower number of total hospital days (8.7+/-0.9 vs 12.8+/-1.1 days; p=0.009). Clinically relevant but not statistically significant differences in hospital costs ($16,642+/-2,841 vs $24,052+/-3,466, p=0.11) also favored the VATS group. Of note, all the CT-SK treatment failures could be salvaged with VATS, and none required thoracotomy. CONCLUSIONS: In patients with loculated, complex fibrinopurulent parapneumonic empyema thoracis, a primary treatment strategy of VATS is associated with a higher efficacy, shorter hospital duration, and less cost than a treatment strategy that utilizes catheter-directed fibrinolytic therapy.

Adult↗
PubMed1997

Telomerase and telomere inhibitors in preclinical development.

Telomerase is an enzyme required by actively dividing cells to maintain the ends of chromosomes (telomeres). It is present in germline tissue, stem cells and cancer cells, but is repressed in somatic cells. Efforts are underway to exploit this selective expression of telomerase in cancer therapeutics. This review describes the status of telomerase research, which although at present predominantly preclinical, has the potential to enter clinical research.

Journal Article↗
PubMed1997

Circulating T helper 1 (Th1) cell- and Th2 cell-associated cytokines in Indian patients with visceral leishmaniasis.

Sera from 61 Indian patients with visceral leishmaniasis caused by infection with Leishmania donovani were tested for the presence of T helper 1 (Th1) cell-(interferon-gamma [IFN-gamma]) and Th2 cell-associated cytokines (interleukin-4 [IL-4] and IL-10). The IFN-gamma activity was detected in 53%. IL-4 in 84%, and IL-10 in 56% of patient samples. Sera from 10 healthy Indian controls showed detectable IFN-gamma in 90%. IL-4 in 10%, and IL-10 in 20%; corresponding percentages for sera from eight healthy American controls were 100%, 12%, and 0%, respectively. Quantitative data for the 61 patients compared with the 10 Indian controls indicated comparable mean levels of IFN-gamma, but three- and 13-fold increases in IL-10 and IL-4, respectively. Undetectable IFN-gamma activity, observed in 47% of patients, was associated with the presence IL-4 alone or in combination with IL-10 but not with IL-10 alone. In patients who had failed prior therapy (n = 29) compared with previously untreated patients (n = 32). IFN-gamma levels were 67% lower and IL-4 levels were two-fold higher, IL-10 activity was comparable. These results using peripheral blood support the presence of a suppressive Th2 cell-associated immune response in symptomatic Indian kala-azar and point to a possible role for IL-4.

Adult↗
PubMed1997

Effect of silver leaf on circulating lipids and cardiac and hepatic enzymes.

About 50 mg of silver leaf (metallic silver) was given daily by mouth to 30 healthy volunteers for 20 days. A statistically significant hypophospholipidemic, hypotriglyceridemic, hypocholesterolemic and hypoglycemic effect was observed. This was accompanied by a less marked fall in total lipids and significant rise in HDL-cholesterol. In addition, a decrease in plasma enzymes - alkaline phosphatase (ALP), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), creatine phosphokinase (CPK), gamma glutamyl transpeptidase (GGT) and lactate dehydrogenase (LDH) was noted. This was statistically significant for all enzymes except CPK. The safety of ingested silver foil is indicated by absence of pathology in urine and unaltered levels of protein and albumin in the plasma. These observations suggest that silver could be beneficial in conditions like diabetes mellitus, obesity and atherosclerosis.

Female↗
PubMed1997

Transthoracic echocardiography in young patients with acute retinal arterial obstruction. RECO Study Group. Retinal Emboli of Cardiac Origin Group.

OBJECTIVE: To report the transthoracic echocardiographic findings in young patients presenting with acute retinal arterial obstruction, given their clinical risk status for cardioembolic disease. DESIGN: Case series. SETTING: Four North American tertiary hospital centres. PATIENTS: Eleven patients less than 45 years of age presenting with acute retinal arterial obstruction who underwent transthoracic echocardiography. OUTCOME MEASURES: Anticoagulation therapy or cardiac surgery. RESULTS: Echocardiography showed abnormalities in five patients (45%). Five of the 11 patients were at high risk for cardioembolic disease on the basis of a history of risk factors or the presence of a cardiac murmur on presentation, or both. Three (60%) of the five had abnormal findings on echocardiography; all three required anticoagulation therapy or cardiac surgery. Of the six patients at low risk two (33%) had abnormal echocardiograms; neither required anticoagulation therapy or surgical intervention. CONCLUSIONS: All the patients who required anticoagulation therapy or cardiac surgery based on the findings on transthoracic echocardiography were deemed to be at high risk for cardioembolic disease. This emphasizes the importance of clinical risk stratification in the systemic evaluation of young patients presenting with acute retinal arterial obstruction.

Acute Disease↗
PubMed1997

Effect of time and washing on the adhesion of Acanthamoeba to extended wear disposable hydrogel contact lenses.

PURPOSE: This study was undertaken to determine the extent of adhesion of cysts and trophozoites of Acanthamoeba to worn disposable hydrogel lenses and to study the effect of time, lens material, and washing on the adhesion. METHODS: Etafilcon A (58% water content) and Polymacon (38% water content) lenses worn on a 6 night extended wear basis and collected aseptically in PBS pH 7.2, were used for the study. Unworn lenses of the same materials were used as controls. Segments of lenses were incubated in Acanthamoeba suspension (cysts and trophozoites) and examined at 0, 5, and 24 hours, either washed or unwashed, for adherent Acanthamoeba. The amoebae adherent per square mm surface of the lens were enumerated. Levels of adhesion in various groups were compared using Wilcoxon sign rank test. RESULTS: At 0 hours, unwashed worn Polymacon lenses showed significantly greater adherence than Etafilcon A lenses compared to the controls (P = 0.0469). However, there was no difference at 5 and 24 hours exposure time between the lenses. At 24 hours the adhesion of Acanthamoeba was greater for washed worn lenses of both types compared to washed lenses of controls (P = 0.002, 0.012). CONCLUSIONS: Amoebae adhered with equal affinity to both types of lenses but adhered with greater affinity to worn lenses than unworn lenses. Adhesion of Acanthamoeba to worn disposable lenses may be a factor in the pathogenesis of Acanthamoeba keratitis in disposable lens wearers.

Acanthamoeba↗
PubMed1997

Correlation of the pilo-pupil ratio average, a new test for autonomic denervation, to the severity of diabetic retinopathy.

OBJECTIVE: To evaluate the association between the degree of diabetic retinopathy and autonomic neuropathy, and to test whether ocular parasympathetic denervation is correlated to the degree of diabetic retinopathy. DESIGN: Cross-sectional pilot study. SETTING: The tertiary ophthalmic centre for the Atlantic provinces in Halifax. PATIENTS: Twelve randomly selected patients (six women and six men with a mean age of 36.6 years) with insulin-dependent diabetes mellitus who had diabetic retinopathy. OUTCOME MEASURES: Degree of diabetic retinopathy, hemoglobin Alc level, orthostatic change in systolic and diastolic blood pressure and in serum catecholamine levels, degree of pupillary supersensitivity to 0.125% pilocarpine (pilo-pupil ratio average [PPRA]). RESULTS: The degree of diabetic retinopathy was significantly correlated with the duration of diabetes (p = 0.035), the hemoglobin Alc level (p = 0.004), the orthostatic change in diastolic blood pressure (p = 0.022) and the PPRA (p = 0.0007). CONCLUSIONS: The degree of diabetic retinopathy was significantly correlated with autonomic neuropathy and with the PPRA. Given these results, further study is indicated to determine whether autonomic neuropathy is a predictor of the severity of diabetic retinopathy.

Adult↗