重组人白细胞介素-1β对小鼠骨髓粒系细胞和红系细胞的正负调节作用

为阐明IL-1对粒系细胞和红系细胞的作用,我们通过对小鼠骨髓及外周血的研究探讨了IL-1对粒系和红系造血细胞的调节作用.结果表明:IL-1单剂量腹腔注射后第7天红系造血细胞明显减少,外周血网织红细胞在第8天显著下降.在5～10万U/kg剂量范围内IL-1明显促进粒系细胞的增殖.应用流式细胞仪对DNA分析显示IL-1并不引起全骨髓细胞DNA的变化,但大体积细胞在注射IL-1后第3天S期细胞明显增多.我们的结果表明IL-1抑制红系造血细胞的分化增殖,在适当的剂量范围内促进粒系细胞的增殖和分化成熟.其作用的分子基础是诱导造血细胞的细胞周期变化.     

Modulation of carbohydrate metabolism in the selected tissues of marine prawn, Penaeus indicus (H. Milne Edwards), under phosphamidon-induced stress

Changes in carbohydrate metabolism were studied in midgut gland, muscle, and gill tissues of marine prawn Penaeus indicus exposed to a sublethal concentration (0.3 ppm) of phosphamidon. A significant decrease in glycogen and pyruvate and an increase in lactate content were observed in all phosphamidon-exposed prawn tissues after 96 hr. An increase in phosphorylase a and aldolase activity levels suggested the increased formation of triose sugars during phosphamidon toxicity. LDH activity was considerably decreased and an increment in lactate content was observed which indicates reduced mobilization of pyruvate into the citric acid cycle. Glucose-6-phosphate dehydrogenase activity was considerably increased, suggesting the enhanced oxidation of glucose in the hexose monophosphate shunt pathway. Krebs cycle enzymes such as NAD-isocitrate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase were found to be decreased, suggesting the impairment in mitochondrial oxidative metabolism due to the acute toxic impact of phosphamidon. Cytochrome-c oxidase and Mg2+ ATPase activity levels were also decreased considerably, suggesting impaired energy synthesis and breakdown during phosphamidon toxicity, as a result of reduced oxidation of glucose aerobically. The increase in acid and alkaline phosphatase activities indicates the enhanced breakdown of phosphate to release energy in view of inhibiton or impairment in the ATPase system during phosphamidon-induced stress. These results suggest that phosphamidon has a profound effect on the oxidative metabolism of prawn which results in the triggering of compensatory metabolic pathways for survivability.     

Differentiation of pancreatic epithelial progenitor cells into hepatocytes following transplantation into rat liver

The ability to identify, isolate, and transplant progenitor cells from solid tissues would greatly facilitate the treatment of diseases currently requiring whole organ transplantation. In this study, cell fractions enriched in candidate epithelial progenitor cells from the rat pancreas were isolated and transplanted into the liver of an inbred strain of Fischer rats. Using a dipeptidyl dipeptidase IV genetic marker system to follow the fate of transplanted cells in conjunction with albumin gene expression, we provide conclusive evidence that, after transplantation to the liver, epithelial progenitor cells from the pancreas differentiate into hepatocytes, express liver-specific proteins, and become fully integrated into the liver parenchymal structure. These studies demonstrate the presence of multipotent progenitor cells in the adult pancreas and establish a role for the liver microenvironment in the terminal differentiation of epithelial cells of foregut origin. They further suggest that such progenitor cells might be useful in studies of organ repopulation following acute or chronic liver injury.     

Radiotherapy in the treatment of low-grade astrocytomas

Between 1954 and 1986 inclusive, 160 children in the North West Region of England were registered with histologically proven lowgrade astrocytomas (grade 1 or 2). Ten died before receiving any treatment, and a further seven died within 28 days of surgery, leaving 143 children whose survival in relation to treatment modality is the subject of this paper. Low-grade astrocytomas are responsive to radiation therapy. This treatment has no clear benefit to offer children with superficial tumours that can be resected completely or nearly so, but significantly improves survival rates when tumours are deep-seated and not amenable to excision.     

Isolated Castleman disease of the neck: MR findings.

Castleman disease in an 11-year-old girl appeared as a neck mass that grew despite antibiotic treatment. MR showed a well-defined solid mass, isointense with muscle on short-repetition-time/short-echo-time images, with a stellate area of central hypointensity on long-repetition-time/long-echo-time images, that did not enhance with gadolinium.     

Open extremity fracture penetrating the skull

We present a case in which an open fracture of the ulna penetrated the skull and caused a comminuted, depressed skull fracture with a large intraparenchymal hematoma containing bone fragments.     

Post-keratoplasty corneal ulcers and bandage lenses

285 cases of penetrating keratoplasty in whom hydrophilic bandage lenses were fitted were analyzed for the occurrence of corneal ulcers. Of these eyes 26 developed culture-proven bacterial ulcers. No correlation could be made between any particular type of contact lens and the development of corneal ulcer. Although no single factor could be delineated which may be responsible for this problem, this risk appears to be escalated where host defense mechanisms are impaired. The clinician should recognize the potential risk in using bandage lenses when the cornea is immunosuppressed and completely denervated.     

Reaction of dithiothreitol and para-nitroacetophenone with different radical precursors of .OH radical-induced strand break formation of single-stranded DNA in anoxic aqueous solution.

The yields of single-strand breakage (ssb) in single-stranded calf thymus DNA (ssDNA) have been determined after 60Co gamma-irradiation of aqueous anoxic solutions in the presence of different concentrations of dithiothreitol (DTT), ascorbate or trans-4,5-dihydroxy-1,2-dithiane, using low-angle laser light scattering. The influence of DTT on the kinetics of ssb formation has been determined by conductivity measurements in pulse radiolysis. The results suggest that strand breakage in ssDNA proceeds via two modes of about equal contribution and with half-lives of about 7 ms and 0.8s, respectively. Both modes reflect reactions of at least two DNA radicals, which react with DTT by hydrogen-atom transfer reactions with similar rate constants of about 5-9 x 10(5) dm3 mol-1 s-1. These hydrogen-atom transfer reactions inhibit strand break formation. The slow mode is shown to represent the decay of base-radicals to generate sugar radicals. The involvement of the oxidizing .OH adduct radical of guanine in the formation of strand breaks can be ruled out and there is no evidence for a contribution from the anion or radical anion of DTT to the inhibition of strand breaks via electron transfer reactions to DNA radicals.