Search PubMed⌕ Search

Biomedical subjects

J Shah

Publications and source records attributed to J Shah.

At least 163 records · Page 9Linked to original sources
PubMed1994

Cisplatin, fluorouracil, and leucovorin. Increased toxicity without improved response in squamous cell head and neck cancer.

OBJECTIVE: To evaluate the activity and toxicity of the drug combination cisplatin, fluorouracil by continuous infusion, and high-dose oral leucovorin calcium (PFL) as induction chemotherapy in patients with advanced and untreated squamous cell head and neck (SCHN) cancer. DESIGN: Nonrandomized, prospective trial. SETTING: Referral center (comprehensive cancer center). PATIENTS: Twenty-two patients with stage III (n = 7) and IV (n = 15) M0 SCHN cancer of the larynx (n = 13), hypopharynx (n = 7), and oropharynx (n = 2) whose standard treatment would have required total laryngectomy. INTERVENTIONS: Three cycles of PFL were administered prior to local-regional therapy (concomitant cisplatin and radiation and/or neck dissection, with total laryngectomy reserved for nonresponse or relapse). Chemotherapy included cisplatin (100 mg/m2) on day 1 by short intravenous infusion; fluorouracil (800 mg/m2) on days 1 through 5 by continuous infusion; and leucovorin (100 mg) every 4 hours by mouth for 30 doses. The PFL combination was administered every 21 days. MAIN OUTCOME MEASURES: Clinical response to chemotherapy and observed toxic effects during chemotherapy. RESULTS: Five patients were inevaluable for response, with three early deaths (infection in two and sudden death in one), one cerebrovascular accident, and one patient declining further chemotherapy. Of the remaining 17 patients, 10 had a major response to chemotherapy, but in only five patients (29%) was this complete (95% confidence interval, 8% to 51%). Other significant toxic effects included grade 3 to 4 mucositis in eight patients and grade 3 to 4 neutropenia in 10. CONCLUSIONS: While PFL is active in patients with SCHN cancer, we were unable to reproduce the high complete response rates reported by other centers. Its use can be associated with significant toxic effects. We do not recommend the use of PFL for the treatment of patients with SCHN cancer outside the context of a clinical trial until there is further critical assessment of its activity and toxicity.

Adult↗
PubMed1994

The relationship of loss of heterozygosity to tobacco exposure and early recurrence in head and neck squamous cell carcinoma.

BACKGROUND: Tobacco usage contributes to carcinomas of the lung, bladder, esophagus, uterine cervix, and head and neck, and can induce specific genetic lesions. Studies of the above tumor types have documented allelic deletions affecting 3p, 5q, 9p, 9q, 10q, 11p, 13q, 17p, and 18q. Relationships between genetic loss, tobacco exposure, and patient outcome have not been described. PATIENTS AND METHODS: To confirm and further define loss of heterozygosity in head and neck squamous cell carcinoma (HNSCC), and to examine relationships between loss of heterozygosity and both tobacco exposure and early recurrence, we undertook this study on previously untreated patients with HNSCC. We performed a Southern blot analysis using 11 probes specific for loci deleted in tobacco-associated cancers. We have investigated 42 prospectively collected, paired samples of HNSCC and peripheral blood. Demographic and follow-up data were collected on these patients. RESULTS: Significant loss of heterozygosity was observed in descending order of frequency at 11p, 9p, 17p, 3p, 10q, and 13q. All nonsmokers showed loss of heterozygosity on one or more loci compared with only 53% of smokers (P < 0.05). Furthermore, patients with multiple deletions had a significantly higher rate of early recurrence than those with fewer deletions (P < 0.05). CONCLUSION: Multiple deletions occurred more frequently in nonsmokers and predicted a higher risk of early recurrence.

Blotting, Southern↗
PubMed1994

Structure and thermotropic properties of 1-stearoyl-2-acetyl-phosphatidylcholine bilayer membranes.

The structural and thermotropic properties of 1-stearoyl-2-acetyl-phosphatidylcholine (C(18):C(2)-PC) were studied as a function of hydration. A combination of differential scanning calorimetry and x-ray diffraction techniques have been used to investigate the phase behavior of C(18):C(2)-PC. At low hydration (e.g., 20% H2O), the differential scanning calorimetry heating curve shows a single reversible endothermic transition at 44.6 degrees C with transition enthalpy delta H = 6.4 kcal/mol. The x-ray diffraction pattern at -8 degrees C shows a lamellar structure with a small bilayer periodicity d = 46.3 A and two wide angle reflections at 4.3 and 3.95 A, characteristic of a tilted chain, L beta' bilayer gel structure. Above the main transition temperature, a liquid crystalline L alpha phase is observed with d = 53.3 A. Electron density profiles at 20% hydration suggest that C(18):C(2)-PC forms a fully interdigitated bilayer at -8 degrees C and a noninterdigitated, liquid crystalline phase above its transition temperature (T > Tm). Between 30 and 50% hydration, on heating C(18):C(2)-PC converts from a highly ordered, fully interdigitated gel phase (L beta') to a less ordered, interdigitated gel phase (L beta), which on further heating converts to a noninterdigitated liquid crystalline L alpha phase. However, the fully hydrated (> 60% H2O) C(18):C(2)-PC, after incubation at 0 degrees C, displays three endothermic transitions at 8.9 degrees C (transition I, delta H = 1.6 kcal/mol), 18.0 degrees C (transition II), and 20.1 degrees C (transition III, delta HII+III = 4.8 kcal/mol). X-ray diffraction at -8 degrees C again showed a lamellar gel phase (L beta') with a small periodicity d = 52.3 A. At 14 degrees C a less ordered, lamellar gel phase (L beta) is observed with d = 60.5 A. However, above the transition III, a broad, diffuse reflection is observed at approximately 39 A, consistent with the presence of a micellar phase. The following scheme is proposed for structural changes of fully hydrated C(18):C(2)-PC, occurring with temperature: L beta' (interdigitated)-->L beta (interdigitated)-->L alpha(noninterdigitated)-->Micelles. Thus, at low temperature C(18):C(2)-PC forms a bilayer gel phase (L beta') at all hydrations, whereas above the main transition temperature it forms a bilayer liquid crystalline phase L alpha at low hydrations and a micellar phase at high hydrations (> 60 wt% water).

Biophysical Phenomena↗