Induction of acute phase gene expression by brain irradiation

PURPOSE: To investigate the in vivo acute phase molecular response of the brain to ionizing radiation. METHODS AND MATERIALS: C3Hf/Sed/Kam mice were given midbrain or whole-body irradiation. Cerebral expression of interleukins (IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6), interferon (IFN-gamma), tumor necrosis factors (TNF-alpha and TNF-beta), intercellular adhesion molecule-1 (ICAM-1), inducible nitric oxide synthetase (iNOS), von Willebrand factor (vWF), alpha 1-antichymotrypsin (EB22/5.3), and glial fibrillary acidic protein (GFAP) was measured at various times after various radiation doses by ribonuclease (RNase) protection assay. The effects of dexamethasone or pentoxifylline treatment of mice on radiation-induced gene expression were also examined. RESULTS: Levels of TNF-alpha, IL-1 beta, ICAM-1, EB22/5.3 and to a lesser extent IL-1 alpha and GFAP, messenger RNA were increased in the brain after irradiation, whether the dose was delivered to the whole body or only to the midbrain. Responses were radiation dose dependent, but were not found below 7 Gy; the exception being ICAM-1, which was increased by doses as low as 2 Gy. Most responses were rapid, peaking within 4-8 h, but antichymotrypsin and GFAP responses were delayed and still elevated at 24 h, by which time the others had subsided. Pretreatment of mice with dexamethasone or pentoxifylline suppressed radiation-induced gene expression, either partially or completely. Dexamethasone was more inhibitory than pentoxifylline at the doses chosen. CONCLUSIONS: The initial response of the brain to irradiation involves expression of inflammatory gene products, which are probably responsible for clinically observed early symptoms of brain radiotherapy. This mechanism explains the beneficial effects of the clinical use of steroids in such circumstances.     

Ethanol consumption and resistance are inversely related to neuropeptide Y levels

Genetic linkage analysis of rats that were selectively bred for alcohol preference identified a chromosomal region that includes the neuropeptide Y (NPY) gene. Alcohol-preferring rats have lower levels of NPY in several brain regions compared with alcohol-non-preferring rats. We therefore studied alcohol consumption by mice that completely lack NPY as a result of targeted gene disruption. Here we report that NPY-deficient mice show increased consumption, compared with wild-type mice, of solutions containing 6%, 10% and 20% (v/v) ethanol. NPY-deficient mice are also less sensitive to the sedative/hypnotic effects of ethanol, as shown by more rapid recovery from ethanol-induced sleep, even though plasma ethanol concentrations do not differ significantly from those of controls. In contrast, transgenic mice that overexpress a marked NPY gene in neurons that usually express it have a lower preference for ethanol and are more sensitive to the sedative/hypnotic effects of this drug than controls. These data are direct evidence that alcohol consumption and resistance are inversely related to NPY levels in the brain.     

Giant cell tumor (osteoclastoma) of the mandible: a diagnostic dilemma and a therapeutic challenge

We have recently identified a novel RNA sequence in ameloblasts, coding for amelin (Cerny et al., 1996). In the present paper, its expression has been compared with that of amelogenin in developing incisors and molars of rats, by means of in situ hybridization of paraffin sections. The RNAs for both amelin and amelogenin were highly expressed in secretory ameloblasts. The expression of RNA for amelogenin gradually decreased in the post-secretory ameloblasts. In contrast, the RNA expression for amelin remained high in post-secretory ameloblasts up to the stage of fusion between dental and oral epithelia at the time of tooth eruption. We suggest that amelin might be involved in the mineralization of enamel or in the attachment of ameloblasts to the enamel surface. The whole-mount in situ hybridization procedure is described for the first time in dental research. It proved to be a useful method and confirmed the results of the conventional in situ hybridization.     

The intraoperative assessment of ascending aortic atheroma: epiaortic imaging is superior to both transesophageal echocardiography and direct palpation

Effective models of delivery of directly observed therapy (DOT) for tuberculosis in resource-poor settings are needed. Intermittent chemotherapy may be an important component of DOT delivered in the community as it means fewer visits to supervisors. There is no published evidence on the efficacy of twice weekly therapy given from the start of treatment without an intensive daily phase. We analysed data from 3 large cohort studies in a migrant, urban workforce in South Africa between 1975 and 1983. All patients received 4 drugs (isoniazid, rifampicin, pyrazinamide and streptomycin) twice weekly under direct observation by a nurse in the workplace. Of 444 patients, 378 (85.1%) completed treatment. Cure could be assessed in 362, and 348 (96.1%, 95% confidence interval 93.7-97.8%) were bacteriologically cured. Sputum status was assessed at 2-3 months in 343 patients and 309 (90.1%) were sputum negative. Eighteen patients relapsed (5.7%; 2.9/100 patient-years of observation). DOT can be effectively delivered to a migrant, urban workforce, and 4-drug therapy given twice weekly under direct observation is efficacious.     

Kainate-induced retina amacrine-like cell damage is mediated by AMPA receptors

We investigated the effect of domoate, kainate and AMPA on 45Ca2+ uptake and on metabolic activity of cultured chick amacrine-like cells, as measured by reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Domoate and kainate stimulated 45Ca2+ uptake and decreased MTT reduction, in a LY 303070-sensitive manner. AMPA caused a small increase on 45Ca2+ uptake, but it was without effect on MTT reduction. AMPA reduced both the 45Ca2+ entry and neurotoxicity induced by kainate, and cyclothiazide enhanced both the 45Ca2+ entry and neurotoxicity induced by AMPA. The results indicate that the AMPA receptors are the non-NMDA glutamate receptors involved in excitotoxicity.     

Clinical aspects of strabismus with insufficiency of the superior oblique muscle

In Europe patients are increasingly entering the healthcare debate, demanding explanations and questioning medical practice and clinical nursing traditions, at a time when human and financial resources are short and the relevancy of standard setting and quality assurance activities are being questioned. Working on heavily loaded units, nurses may feel tempted to dismiss the need for systematic evaluation of their work. However, quality assurance may be the way to empower nurses, but only if done collectively.     

螺杆式制冷压缩机新技术应用的进展

本文主要就目前市场上推出的螺杆式制冷压缩机新产品作一解剖,综述了许多新技术的应用,以供读者参考。