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991.
Lactic acidosis due to thiamine deficiency is known to complicate chemotherapy and radiotherapy treatment of malignant extracranial tumors, but to the authors' knowledge, this complication has not been reported in patients treated for malignant brain tumors. They report three such cases, demonstrating that this complication can occur during treatment of brain tumors. In all patients, consciousness levels deteriorated within 1 to 2 days. Serum lactic acid levels increased to concentrations between 62 and 96.7 mg/dl, resulting in severe metabolic acidosis. A low blood thiamine level (9 ng/ml) was demonstrated at the onset in one case, and high-dose thiamine infusions dramatically improved lactic acidemia as well as impairment of consciousness in two cases. In the other case, hydrocephalus was suspected initially, resulting in a delay in thiamine supplementation. Clinical differentiation of this form of lactic acidosis from hydrocephalus or tumor progression can be very difficult in a patient undergoing treatment for a malignant brain tumor. Demand for thiamine is thought to be increased in patients with malignant brain tumors, and supplemental thiamine during treatment is necessary to prevent lactic acidosis. When this complication occurs, immediate treatment with sufficient thiamine is essential, together with normalization of pH by using sodium bicarbonate. With timely intervention, the level of consciousness can recover to the preacidotic state with no new neurological deficits.  相似文献   
992.
Reading in peripheral vision is slow and requires large print, posing substantial difficulty for patients with central scotomata. The purpose of this study was to evaluate the effect of print size on reading speed at different eccentricities in normal peripheral vision. We hypothesized that reading speeds should remain invariant with eccentricity, as long as the print is appropriately scaled in size--the scaling hypothesis. The scaling hypothesis predicts that log-log plots of reading speed versus print size exhibit the same shape at all eccentricities, but shift along the print-size axis. Six normal observers read aloud single sentences (approximately 11 words in length) presented on a computer monitor, one word at a time, using rapid serial visual presentation (RSVP). We measured reading speeds (based on RSVP exposure durations yielding 80% correct) for eight print sizes at each of six retinal eccentricities, from 0 (foveal) to 20 deg in the inferior visual field. Consistent with the scaling hypothesis, plots of reading speed versus print size had the same shape at different eccentricities: reading speed increased with print size, up to a critical print size and was then constant at a maximum reading speed for larger print sizes. Also consistent with the scaling hypothesis, the plots shifted horizontally such that average values of the critical print size increased from 0.16 deg (fovea) to 2.22 deg (20 deg peripheral). Inconsistent with the scaling hypothesis, the plots also exhibited vertical shifts so that average values of the maximum reading speed decreased from 807 w.p.m. (fovea) to 135 w.p.m. (20 deg peripheral). Because the maximum reading speed is not invariant with eccentricity even when the print size was scaled, we reject the scaling hypothesis and conclude that print size is not the only factor limiting maximum reading speed in normal peripheral vision.  相似文献   
993.
The Staphylococcus aureus 8325-4 hyaluronate lyase gene (hysA) was identified after detecting hyaluronate lyase activity expressed by phages from a genomic library. The hysA open reading frame, capable of encoding a protein of 91 980 Da, was identified by Tn5 mutagenesis and nucleotide sequencing. HysA shares 35 and 36% amino acid sequence identity with group B streptococcal hyaluronate lyase and pneumococcal hyaluronidase, respectively. A 94-kDa protein was expressed in Escherichia coli minicells, a result consistent with the coding capacity of hysA. Identification of the S. aureus 8325-4 hyaluronate lyase gene will allow the regulation of this putative virulence determinant to be studied.  相似文献   
994.
BACKGROUND: The supply of solid organs for transplantation will never meet the growing demand. Xenotransplantation is considered to be a potential solution for the critical shortage of allografts. However, xenograft rejection is currently not controlled by conventional immunosuppressive agents. Bone marrow chimerism induces donor-specific tolerance without the requirement for chronic immunosuppressive therapy. The aim of this study was to develop a nonlethal recipient-conditioning approach to achieve mixed bone marrow chimerism and donor-specific tolerance. METHODS: C57BL/10SnJ mice were conditioned with total body irradiation followed by a single injection of cyclophosphamide on day +2. On day 0, mice were reconstituted with untreated bone marrow cells from Fischer 344 rats. Recipients were analyzed by flow cytometry for donor bone marrow engraftment and multilineage chimerism. Donor-specific tolerance was tested by skin grafting. RESULTS: One hundred percent of recipients engrafted after irradiation with 600 cGy total body irradiation, transplantation with 80 x 10(6) Fischer 344 bone marrow cells, and injection with 50 mg/kg cyclophosphamide intraperitoneally. Donor chimerism was detectable in all engrafted animals for up to 11 months. This conditioning was nonlethal, because conditioned untransplanted animals survived indefinitely. Mixed xenogeneic chimeras were tolerant to donor-specific skin grafts but rejected third-party (Wistar Furth) grafts as rapidly as naive C57BL/10SnJ mice. In contrast, animals that received less efficacious conditioning regimens and did not exhibit detectable chimerism showed prolonged graft survival, but delayed graft rejection occurred in all animals within 10 weeks. CONCLUSION: The induction of bone marrow chimerism and donor-specific tolerance after nonlethal conditioning might be useful to prevent the vigorous cellular and humoral rejection response to xenografts.  相似文献   
995.
In many different murine models, the immunogenicity of tumor cells can be increased by transduction with a range of immunostimulatory genes, inducing an immune response that causes regression of pre-existing unmodified tumor cells. To investigate the relevance of these animal models to pediatric malignancy, we used autologous unirradiated tumor cells transduced with an adenovirus-IL-2 to immunize 10 children with advanced neuroblastoma. In a dose-escalation study, we found that this tumor immunogen induced a moderate local inflammatory response consisting predominantly of CD4(+) T lymphocytes, and a systemic response, with a rise in circulating CD25(+) and DR+ CD3(+) T cells. Patients also made a specific antitumor response, manifest by an IgG antitumor antibody and increased cytotoxic T-cell killing of autologous tumor cells. Clinically, five patients had tumor responses after the tumor immunogen alone (one complete tumor response, one partial response, and three with stable disease). Four of these five patients were shown to have coexisting antitumor cytotoxic activity, as opposed to only one of the patients with nonresponsive disease. These results show a promising correlation between preclinical observations and clinical outcome in this disease, and support further exploration of the approach for malignant diseases of children.  相似文献   
996.
This study examined the early response of pro-inflammatory and regulatory cytokines in the mouse brain following triethyltin (TET)-induced myelin injury characterized by edematous vacuolation. Following an acute intraperitoneal injection of triethyltin (TET) sulfate (3 mg/kg) to 17-day old CD1 mice, significant increases in brain stem TNF-alpha and IL-1alpha mRNA levels occurred at 6 and 24 h, respectively with elevations in TGF-beta1 and MIP-1alpha at 1 h. In the cortex, responses were limited to elevations at 6 h in TNF-alpha, TGF-beta1 and MIP-1alpha. These data suggest that a chemokine/cytokine response can occur with minimal alterations to the integrity of the myelin sheath and may contribute to the initial signaling mechanisms associated with demyelinating disorders.  相似文献   
997.
Despite the increasing awareness of the important role that Accident and Emergency (A&E) personnel have in the diagnosis and management of domestic violence victims, there is limited knowledge about the nurses' or doctors' knowledge of or attitudes to domestic violence in Australian health care settings. In addition nursing and medical staff still receive very little training in working with domestic violence victims. This study was conducted to examine the existing knowledge, attitudes to and management strategies for domestic violence victims among 111 nurses and doctors in two rural and two country hospitals. The findings indicate that A&E staff recognise the importance of their role in the identification and management of domestic violence victims. Despite this they do not have all the skills necessary to deal effectively with the problem or to be able to access local resources for assistance. Education programs should focus on direct questioning techniques, and recognition of risk factors and protocols to provide guidelines for police involvement.  相似文献   
998.
999.
Samples of duck eggs were collected from 65 farms distributed in 6 counties in Taiwan to analyze the contents of Pb, Cd, Hg, and Cu in albumen and yolk. Lead, Cd, and Cu determinations were performed by microwave digestion together with atomic absorption spectrophotometry, whereas Hg was analyzed by sulfuric acid-nitric acid digestion and cold vapor atomic absorption spectrophotometry. Expressed on a wet weight basis, the average concentrations (ranges) of the four metals were as follows: Pb, 13.6 ng/g (.8 to 27.5) in albumen and 84.7 ng/g (44.8 to 224.7) in yolk; Cd, 1.8 ng/g (< .5 to 4.4) in albumen and 3.8 ng/g (< 1.0 to 5.7) in yolk; Hg, 17.8 ng/g (2.5 to 47.5) in albumen and 9.7 ng/g (1.2 to 20) in yolk; Cu, .83 micrograms/g (.56 to 1.08) in albumen and 1.36 micrograms/g (.95 to 1.95) in yolk. Comparison of the calculated daily intakes of Pb, Cd, and Hg from eggs with the World Health Organization-Food Agriculture Organization provisional tolerated daily intakes suggest that duck eggs are safe with respect to the contents of the three metals. Eggs are poor sources of Cu, supplying less than 2% of the Recommended Dietary Allowance.  相似文献   
1000.
1. Bovine aortic endothelial (BAE) cells contain two co-existing receptors for extracellular ATP, the P2Y and P2U-purinoceptors. Here we have determined whether the proposed P2X-purinoceptor antagonist, pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid (PPADS) could distinguish between these two receptor subtypes. 2. Cells labelled with myo-[2-3H]-inositol were stimulated with increasing concentrations of either the P2Y-agonist, 2MeSATP, or the P2U-agonist, UTP in the absence or presence of 30 microM PPADS. The accumulation of total [3H]-inositol (poly)phosphates mediated by 2MeSATP was markedly attenuated by PPADS, whereas the response to UTP was not significantly affected. 3. Stimulation of BAE cells with increasing concentrations of ATP showed a reduced response in the presence of 10 microM PPADS, but this effect of the antagonist was not significant. By contrast, inhibition of the response to ADP was profound and highly significant. 4. These observations show that PPADS is not a selective P2X-purinoceptor antagonist, but is able to distinguish between P2Y- and P2YU-purinoceptors in BAE cells, and indicate that this compound may provide a useful tool in the study of multiple subtypes of P2-purinoceptors. Furthermore the results are consistent with the hypothesis that ATP interacts with both receptor subtypes, but that the action of ADP is primarily at the P2Y-purinoceptor in these endothelial cells.  相似文献   
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