RESUMO
Seasonal plasticity in the small intestine of neonatal tegu lizards was investigated using morphometry and analysis of enzymes involved in supplying energy to the intestinal tissue. In the autumn, the intestinal mass (Mi) was 1.0% of body mass and the scaling exponent b=0.92 indicated that Mi was larger in smaller neonates. During arousal from dormancy Mi was 23% smaller; later in spring, Mi increased 60% in relation to the autumn and the exponent b=0.14 indicated that the recovery was disproportionate in smaller tegus. During the autumn, the intestinal villi were greatly elongated; by midwinter, the Hv, SvEp, and VvEp were smaller than during the autumn (59%, 54%, 29%) and were restored to autumn levels during spring. In the active tegus, the maximum activity (Vmax) of enzymes indicated that the enterocytes can obtain energy from different sources, and possess gluconeogenic capacity. During winter, the Vmax of CS, HOAD, GDH, PEPCK was 40-50% lower in relation to the autumn and spring, while the Vmax of HK, PK, LDH, AST was unchanged. The hypoglycemia and the mucosal atrophy/ischemia during winter would prevent the enterocytes from using glucose, whereas they could slowly oxidize fatty acids released from body stores and amino acids from the tissue proteolysis to satisfy their needs of energy. Contrastingly, starvation during spring caused severe mass loss (50%); the tissue protein and the VvEp and VvLP did not change while the thickness of the muscular layer increased 51%, which suggested different effects along the length of the organ. In addition, the Vmax of the glycolytic enzymes was lower, indicating that a regulatory mechanism would spare blood glucose for vital organs during unanticipated food restriction.
Assuntos
Jejum , Hibernação , Intestino Delgado/metabolismo , Lagartos/fisiologia , Animais , Peso Corporal , Lagartos/crescimento & desenvolvimento , Estações do AnoRESUMO
The primary goal of this phase II study was to determine the efficacy of gemcitabine (Gemzar; Eli Lilly and Company, Indianapolis, IN) plus 5-fluorouracil in patients with pancreatic cancer. Eligibility criteria included nonresectable locally advanced or metastatic pancreatic adenocarcinoma and measurable disease. Gemcitabine at 1,000 mg/m(2) and leucovorin at 20 mg/m(2) were administered intravenously 30 minutes before 5-fluorouracil 600 mg/m(2), weekly for 3 of every 4 weeks. Twenty nine patients were enrolled. The overall response rate was 21% (95% confidence interval: 8% to 40%), consisting of one complete response and five partial responses; 16 patients (55%) had stable disease. Median survival was 8.4 months (95% confidence interval: 2.6 to 14.2), and actuarial 1-year survival was 36%. Neutropenia (grade 3 only) was reported in 3.4% of patients, but was generally of short duration. No thrombocytopenia or evidence of cumulative myelosuppression was observed. The only significant nonhematologic events were grade 3 diarrhea and alopecia (both 3.4%). Gemcitabine plus 5-fluorouracil is active and well tolerated compared with results reported for each of these single agents. Thus, this combination justifies future comparative clinical trials. Semin Oncol 28 (suppl 10):44-49.