Biomedical subjects
Publications and source records attributed to P Chandra.
Cholangiocarcinoma is one of the most common malignancies of the biliary tree. Most cases are perihilar. Cholangiocarcinoma usually has an indolent, slowly progressive course and is associated with a high mortality rate. In this article, we discuss the management of perihilar cholangiocarcinoma by radiation therapy and chemotherapy in a case in which no recurrence was found on autopsy.
Patterns of antibody response to recombinant transactivator protein (HIV-1 tat) in serum samples from HIV-1-negative persons (n = 60), HIV-1-infected asymptomatic persons (n = 20), HIV-1-infected people with Kaposi's sarcoma (n = 25) and of people with Kaposi's sarcoma without HIV-1 infection have been analyzed. None of the healthy people had anti-tat IgG in their serum. All asymptomatic patients with HIV-1 infection were anti-tat IgG-positive. Epitope mapping revealed that these sera have anti-tat IgG to all the functional domains of tat protein. Four of the 25 HIV-1-infected patients with Kaposi's sarcoma were anti-tat IgG-positive; however, epitope analysis revealed that IgG to functional domains of tat protein, in particular to TAR-binding site, were absent. All patients with Kaposi's sarcoma without HIV-1 infection were anti-tat IgG-negative. Presence or absence of anti-tat IgG, and prevalence of different antibody profiles in different groups of patients suggest the pathophysiologic role of tat protein. Thus, a passive immunization with anti-tat IgG could be a useful strategy to influence the pathophysiologic state of the disease.
Monoclonal antibodies (mAbs) directed against the amino-terminal region (N-terminal sequence 2-19) of transactivator protein (tat) of HIV-1 have been shown to inhibit intercellular transactivation mediated by the extracellular tat protein. The intracellular transactivation was not significantly affected by anti-tat mAbs. The specificity of anti-tat mAbs in abolishing the transactivating potential of extracellular tat is documented by studies with mAbs to HIV-1 reverse transcriptase, or to a human mammary cancer protein. None of these antibodies showed any inhibitory effect on intercellular transactivation. Specific interaction of anti-tat IgG with tat protein expressed in Jurkat cells is further supported by experiments on immunoblotting. Extracellular tat is responsible for signals which induce a variety of biological responses in HIV-infected cells, as well as in uninfected cells. The fact that anti-tat mAbs can abolish the intercellular traffic of tat protein offers a unique strategy in the development of vaccines against AIDS.
We report an interesting case with bilateral PTFE aorto-renal grafts of which one graft underwent balloon angioplasty and stenting for proximal stenosis. Combined debulking by AngioJet thrombectomy and Simpsons directional atherectomy was performed within the stent following reocclusion of the graft 9 months later.
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OBJECTIVES: While the unemployment rate of African-American people is more than twice that of the white population, the research on the impact of unemployment on the health of this population is scarce. This study analysed the impact of unemployment on depression and well being among African-American people, and the factors associated with well being. METHODS: Logistic and multiple regression models were used to analyse panel data collected in the National Survey of Families and Households 1987-1992. African-American (1369) and white (6660) respondents were analysed separately. Outcome variables included an index of depression and self reported health status. MAIN FINDINGS: Differences between employment and unemployment groups were less significant for African-Americans than for the white population in predicting depression and well being. Health enhancing factors such as education and wealth were significantly associated with better health and lower depression indices among the white population but not consistently so among African-Americans. Satisfaction with personal relationships was the strongest predictor of well being for both groups. CONCLUSION: Research should focus on the special needs and circumstances of African-Americans, because protective factors may not have the same impact in different groups of the population.
PURPOSE: This is a prospective study to improve the therapeutic ratio in the treatment of patients with locally advanced nasopharyngeal and paranasal sinus tumors by using split-course concomitant infusion cisplatin chemotherapy and hyperfractionated radiotherapy. METHODS AND MATERIALS: From 1983 to 1993, 21 patients with locally advanced nasopharyngeal and paranasal sinus tumors (T3 and T4, or recurrent tumors involving the facial bones and/or the base of the skull) were treated with a regimen of split-course hyperfractioned radiotherapy (1.2 Gy/fraction/bid) and concomitant infusion cisplatin (5-10 mg/m2/24 h). The therapy was given in three separate 2-week sessions with 1 to 2 week breaks between sessions. Seventeen of 21 patients were treated with curative intent with cumulative radiation doses ranging from 64.8 to 70.8 Gy. Four patients were treated with palliative intent to a total dose of less than 60 Gy or to a limited field due to previous irradiation. RESULTS: Sixteen of 17 patients (94%) treated curatively achieved a complete response. Of the 16 patients who achieved complete response, 7 patients (50%) were alive at the time of analysis (36 to 126 months). One patient was alive at 4 years with no evidence of disease, and died in 10 years at the age of 80 of unknown cause. Two patients died of local recurrence at 21 and 45 months and one patient died of a cerebrovascular accident at 12 months with disease status unknown. Five patients died of distant metastases. The one patient who had a partial response died in 25 months with local disease and metastases to the bone and lung. Four patients that were previously irradiated received a reduced total dose or treated to a limited irradiation field. All had near complete responses, but died within a year of treatment, with the exception of one patient who died at 23 months. Acute reactions included intense erythema of the mucosa in all patients. Five of 21 (23%) developed punctate mucositis and 3 of 21 (14%) developed confluent mucositis. Hematologically, one patient developed neutropenia (1800 WBC/mm3) and one developed thrombocytopenia (38,000/mm3). A rising creatinine was observed in three patients (2.0, 1.7, 1.7) all of whom were treated with the higher 10 mg/m2/day dose of infusional cisplatin. In all three of these cases, the creatinine slowly returned to normal over a 6-month period. Hormonal evaluations were performed in three patients and all were within normal ranges. There was no evidence of neck fibrosis or trismus. One patient with gross recurrent disease of the orbit developed blindness of the involved eye due to corneal opacification. The orbital area had been reirradiated in this patient. CONCLUSIONS: Concomitant infusion cisplatinum with hyperfractionated radiation improved tumor control, but did not increase normal tissue injury. Acute reactions were minimized by splitting the treatment with a 1- to 2-week break after each 2 weeks of radiation treatment. Late complications were not increased by using a hyperfractionated radiation regimen. The local failure rate was only 18% (3 of 17 patients), but the distant failure rate was 35% (6 patients). Further investigation is needed to prove if adjuvant chemotherapy after concomitant chemoradiation improves survival by decreasing the distant failure in such advanced cases.
The protein secretion patterns in a macrophage-like cell line (CBrD), established from the peritoneal cells of NMRI mice treated with the dioxin analog 2,3,7,8-tetrabromodibenzo-p-dioxin (TBrDD), were analyzed by high resolution two-dimensional gel electrophoresis (2-D PAGE), and compared to the pattern of proteins secreted by control macrophages which were intraperitoneally activated by bacterial lipopolysaccharide. The most striking alterations were observed in the low molecular range. The transformed cells encode a number of low molecular mass proteins (10-20 kDa) which were not detected in control cells under identical experimental conditions. The protein pattern with respect to isoelectric point, molecular weight, optical density (OD) and area of the spot (in mm2) has been depicted by computer analysis in relation to a standardized spot outline and the spot's background (in OD). It is concluded that the transformation of murine peritoneal macrophages by TBrDD leads to an upregulation of proteins, in particular of low-molecular-weight proteins.
The effect of iron (FeCl3) on chlorophyll content, lipid peroxidation product, potassium ion leakage (a measure of damage to the permeability barrier), and antioxidants was studied in Hydrilla verticillata. The effect of iron-induced damage to the plant was compared with those of N-ethyl maleimide (NEM), a sulfhydryl reagent, and cumene hydroperoxide (CHP), an organic peroxide known to induce lipid peroxidation by free radical formation. The level of lipid peroxidation product was increased in the plants treated with Fe, CHP, and CHP + NEM but not with NEM alone. A significant increase in potassium ion leakage to the external solution was observed by the addition of Fe, CHP, and CHP + NEM, while this did not increase significantly in NEM-treated plants. When NEM and CHP were added simultaneously, the results were the same as those obtained with high iron concentrations, suggesting a combined effect of thiol depletion and lipid peroxidation by Fe ions. In addition, the results indicated loss of glutathione (GSH) and increased oxidized glutathione (GSSG) under Fe stress, indicative of oxidative stress. The oxidative stress may increase the production of free radicals and subsequently resulted in peroxidation of lipids. Further, addition of iron increased the activity of superoxide dismutase (SOD) which may be due to enhanced production of oxygen free radical and related tissue damage. The results suggest that iron-induced damage in plants can be ascribed to a direct metal action on thiols and by toxic oxygen species. An increase in lipid peroxidation product and K+ leakage are the primary responses of iron toxicity on membrane damage. However, the decrease in chlorophyll content is part of the overall expression of iron toxicity.
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We present a case of severe proximal circumflex artery tortuosity with two 90 degrees bends and then a tight stenosis in the mid part of first obtuse marginal branch. Conventional method used to cross the lesion by wire failed. However, a commercially available new wire with ability to change the degree of tip angulation (Pilot wire, USCI Bard) was then used successfully to cross the stenosis. In addition, the wire straightened the tortuosities and provided good trackability to the balloon. Thus, this new wire is a valuable addition to the angioplasty armamentarium.
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Drug advertisements have important effect in prescribing habits of physicians. WHO states that all the claims in drug advertisements should be supported by suitable documentary evidences (references). The present study evaluated citations (mentioned/not mentioned), sources (journals, books, conferences/symposia, personal testimonial, unpublished data in file) and adequacy (complete/incomplete) of the references in 585 drug advertisements supplied by medical detail persons to different clinical departments of our hospital. The references were cited only in 37.9% of the drug advertisements. In total, 1032 references (76% of journals, 15% of books, 2% of conferences/symposia, 4% of personal testimonials, 1% of unpublished data and 2% of data in file) were cited. Only 10% references of journals, 7% of books and 12% of conferences/symposia were found complete (according to standard bibliographic norms). The current situation can be improved if the government, industry and the prescribers formulate some guidelines for the mentioning of adequate references in drug advertisements.
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