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991.
992.
This study demonstrates by a virologic culture method that human immunodeficiency virus (HIV) resides in bone. After freezing, some initially positive specimens no longer yielded virus, but those that continued to yield virus were not further altered by subsequent washing, which removed essentially all marrow, or by freeze-drying. The safeguards against potential transmission of HIV by a bone allograft are principally the screening and testing methods previously described, although there may be a further reduction of the remote residual risk by the freezing step in the usual technical sequence for tissue banking by sterile techniques.  相似文献   
993.
The cell organization of the pituitary gland and the relationship between neurohypophysis and adenohypophysis in the early developmental stages of the gilthead sea bream, Sparus aurata, were studied by electron microscopy. In newly hatched larvae, the pituitary gland was embedded in the ventral floor of the diencephalon and separated from the hypothalamus by a continuous basal lamina. Elongated mesenchymal cells next to the ventral surface were observed. At this stage, there was no neurohypophysis and the adenohypophysis consisted of undifferentiated endocrine cells with small scarce secretory granules and a few stellate cells, with no distinctive zonation. An incipient neurohypophysis was present in 1-day-old larvae. The first evagination of the neurohypophysis into the adenohypophysis were observed in 2-day-old larvae and developed progressively with age, being deeper in the caudal zone. Two regions in the adenohypophysis, one anterior — the presumptive pars distalis — and one posterior — the presumptive pars intermedia — were found in 2-day-old larvae. Three regions (rostral and proximal pars distalis and pars intermedia) were clearly distinguishable in 4-day-old larvae. The ultrastructural features of the pituitary endocrine cells varied during gland differentiation, with the secretory granules gradually increasing in number and size, accompanying organelle development. Nevertheless, even in the oldest larvae studied (65 days), undifferentiated cells similar to those in the earliest stages were observed. The first blood vessels appeared in the neurohypophysis around 16 days after hatching. During early development, the pituitary gland progressively emerged from the ventral floor of the brain. By 16 days, the principal pattern of the pituitary gland architecture appeared to be established.  相似文献   
994.
995.
1 Cytochrome P450-mediated bioactivation of sulphamethoxazole to a hydroxylamine has been implicated in the hypersensitivity reactions associated with co-trimoxazole administration. Inhibiting the formation of the hydroxylamine may be one method of preventing the high frequency of toxicity which is observed in HIV-infected patients. Therefore, in this study, we have investigated the ability of fluconazole and ketoconazole, known cytochrome P450 inhibitors, to inhibit the formation of sulphamethoxazole hydroxylamine.
2 Ten healthy male volunteers were given co-trimoxazole (800  mg sulphamethoxazole and 160  mg trimethoprim) alone or 1  h after either fluconazole (150  mg) or ketoconazole (200  mg) in a randomized fashion with a washout period of at least 1 week between each phase. Urine was collected for 24  h, and sulphamethoxazole and its metabolites were quantified by electrospray LC-MS.
3 Ketoconazole had no effect on the urinary recovery of sulphamethoxazole or any of its metabolites. In contrast, fluconazole significantly ( P <0.001) inhibited the formation of sulphamethoxazole hydroxylamine by 50.0±15.1%. Fluconazole also inhibited the oxidation of sulphamethoxazole to the 5-methylhydroxy and 5-methylhydroxy acetate metabolites by 69.9±15.8% and 64.0±12.0%, respectively, but had no effect on the amount of sulphamethoxazole, N4-acetyl sulphamethoxazole, or sulphamethoxazole N1-glucuronide excreted in urine.
4 The potential clinical benefit of using fluconazole to prevent hypersensitivity to co-trimoxazole in patients with AIDS needs to be assessed in a prospective study using both metabolite formation and the clinical occurrence of adverse reactions as end-points.  相似文献   
996.
997.
998.
Five commercially available nitropolyclyclic aromatic hydrocarbons (nitro-PAH), namely, 4-nitrobiphenyl, 2-nitrofluorene, 9-nitroanthracene, 1-nitropyrene, and 2,7-dinitrofluorene, were exposed under restricted sunlight in the open air. The direct-acting mutagenicities of the samples after an exposure of 45 days were measured in order to compare them with those of the original samples in the Ames Salmonella typhimurium bioassay. It was found that the mutagenicities of some nitro-PAH do not change significantly while the mutagenicities of others increase or decrease after exposure. A preliminary study of nitro-PAH reaction products after exposure using GC, GC/MS, and FT-IR is also reported.  相似文献   
999.
Twenty-two infants of isolated ventricular septal defect with congestive heart failure were fed with lower-sodium content formula-Lonalac (Mead-Johnson) to study the clinical response of treatment for congestive heart failure. There were no significant changes of intake, urinary output, serum sodium, potassium and osmolality before, 2 days and 6 days after Lonalac feeding. The low sodium content formula may feed the infants with congestive heart failure in addition to the traditional anticongestive therapy.  相似文献   
1000.
Islet cell carcinomas of the pancreas: a twenty-year experience   总被引:16,自引:0,他引:16  
Unlike its lethal exocrine counterpart, islet cell carcinoma of the pancreas is an indolent neuroendocrine neoplasm. The majority of these tumors are hormonally active. When functioning, a number of clinical syndromes (for example, hyperinsulinism, Zollinger-Ellison and Cushing's syndromes) may be evident. Fifty-eight patients surgically treated between 1965 and 1984 were retrospectively analyzed. The purpose of this study was to determine the distribution of functioning versus nonfunctioning tumors and the response to type of therapy. Mean postoperative follow-up was 7.4 years. Survival and prognostic indices were calculated by the Kaplan-Meier method and compared with log-rank tests. Of the group, 54% had functioning and 46% nonfunctioning tumors. Gastrinomas were the most common functioning tumors encountered (19%). Of interest was the finding that nonfunctioning tumors increased steadily during the last 15 years of the study (25% to 65%). Curative resections were performed in 15 (26%) and noncurative procedures in 43 patients (74%), with an overall operative mortality rate of 3%. Symptomatic improvement was achieved in 90% (curative) and 51% (noncurative). Survival at 3 years was 87% and 66% for the curative and noncurative groups, respectively (p less than 0.1), with an overall 5-year survival of 42%. The absence of hepatic metastases was a major predictor of survival at 3 years (82% vs 56%, p less than 0.05). Survival was statistically better at 3 years in those patients with gastrinomas compared with patients with nonfunctioning tumors (91% vs 58%, p less than 0.05). Although surgical cure is rare, significant long-term palliation may be achieved in a large percentage of patients with an aggressive surgical approach, occasional total gastrectomy, combination chemotherapy, H2 blockade, when indicated, and, most recently, with the new long-acting analogue of somatostatin.  相似文献   
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