Cloning and sequencing of a cDNA encoding a copper-zinc superoxide dismutase enzyme from the marine yeast Debaryomyces hansenii

The endothelium and blood platelets are intimately involved in both the maintenance of vascular tone and in haemostasis. They are also exposed to high concentrations of lipoproteins, either in the plasma or in the sub-endothelial region of the artery wall, and the biological activity of these cells has been shown to be modulated. Oxidative modification of these lipoproteins results in further variations in the properties of these particles in relation to the activities of the endothelium and platelets. These effects and how the work of Hermann Esterbauer on the details of lipoprotein oxidation permitted rapid progress in understanding these phenomena are discussed in this review.     

Repeated exposure of adult rats to Aroclor 1254 causes brain region-specific changes in intracellular Ca2+ buffering and protein kinase C activity in the absence of changes in tyrosine hydroxylase

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants, some of which may be neurotoxic. In vitro studies from this laboratory indicated that noncoplanar PCBs perturbed intracellular signal transduction mechanisms including Ca2+ homeostasis, receptor-mediated inositol phosphate production, and translocation of protein kinase C (PKC). In the present study, we examined the effects of PCBs in vivo by dosing adult male Long-Evans rats orally with Aroclor 1254 (0, 10, or 30 mg/kg/day; 5 days/week for 4 weeks) in corn oil. At 24 h after the last dose, rats were tested for motor activity in a photocell device for 30 min. Immediately, the rats were euthanized, blood was collected for thyroid hormone analysis, and brains were removed, dissected into regions (cerebellum, frontal cortex, and striatum), and subcellular fractions were obtained for neurochemical analysis. Following Aroclor 1254 treatment, body weight gain in the high-dose group was significantly lower than the control and low-dose groups. Horizontal motor activity was significantly lower in rats dosed with 30 mg/kg Aroclor 1254. Ca2+ buffering by microsomes was significantly lower in all three brain regions from the 30 mg/kg group. In the same dose group, mitochondrial Ca2+ buffering was affected in cerebellum but not in cortex or striatum. Similarly, total cerebellar PKC activity was decreased significantly while membrane-bound PKC activity was significantly elevated at 10 and 30 mg/kg. PKC activity was not altered either in cortex or the striatum. Neurotransmitter levels in striatum or cortex were slightly altered in PCB-exposed rats compared to controls. Furthermore, repeated oral administration of Aroclor 1254 to rats did not significantly alter forebrain tyrosine hydroxylase immunoreactivity or enzymatic activity. Circulating T4 (total and free) concentrations were severely depressed at both doses in Aroclor 1254-exposed rats compared to control rats, suggesting a severe hypothyroid state. These results indicate that (1) in vivo exposure to a PCB mixture can produce changes in second messenger systems that are similar to those observed after in vitro exposure of neuronal cell cultures; (2) second messenger systems seem to be more sensitive than alterations in neurotransmitter levels or tyrosine hydroxylase involved in dopamine synthesis during repeated exposure to PCBs; and (3) the observed motor activity changes were independent of changes in striatal dopamine levels.     

Identification and sequence analysis of Treponema pallidum tprJ, a member of a polymorphic multigene family

This study examines occupational health and safety provision from farmers' perspectives, to address the question 'Are farmers' health and safety needs being met?' Given that farmers encounter a variety of health and safety risks in the course of their daily work, and that available statistics clearly indicate they are a high risk group, a review of the literature suggests that this area has attracted little research attention. No study has critically examined the system of occupational health and safety provision for farmers and no attempts have been made to elicit farmers' perspectives on the subject. A telephone survey using a questionnaire divided into four sections, involving a random sample of 150 farmers from the counties of Cumbria, Cheshire and Cambridgeshire in England, found that farmers considered the system of occupational health and safety provision to be inadequate and that their occupational health and safety needs were not being met. Recommendations for improvements are made based on the results of the survey.     

Viracept (nelfinavir mesylate, AG1343): a potent, orally bioavailable inhibitor of HIV-1 protease

Using a combination of iterative structure-based design and an analysis of oral pharmacokinetics and antiviral activity, AG1343 (Viracept, nelfinavir mesylate), a nonpeptidic inhibitor of HIV-1 protease, was identified. AG1343 is a potent enzyme inhibitor (Ki = 2 nM) and antiviral agent (HIV-1 ED50 = 14 nM). An X-ray cocrystal structure of the enzyme-AG1343 complex reveals how the novel thiophenyl ether and phenol-amide substituents of the inhibitor interact with the S1 and S2 subsites of HIV-1 protease, respectively. In vivo studies indicate that AG1343 is well absorbed orally in a variety of species and possesses favorable pharmacokinetic properties in humans. AG1343 (Viracept) has recently been approved for marketing for the treatment of AIDS.     

Induction of NG108-15 cells differentiation by human bone marrow stromal cells

The survival and differentiation of neuronal cells is dependent on factors such as neurotrophins, cytokines and components of extracellular matrix. Bone marrow stromal cells have been shown to support the growth and differentiation of neuroblastoma cells. In an attempt to study the effects of bone marrow stromal cells on neuronal differentiation, we have co-cultured neuroblastoma x glioma hybrid NG108-15 cells with human bone marrow stromal cells. After co-culturing, clones exhibiting morphological differentiated phenotype and high level of neurofilament expression were isolated. Interestingly, these clones maintain their ability to proliferate in contrast to differentiated NG108-15 cells induced by dibutyryladenosine 3',5'-cyclic monophosphate. These results suggested that bone marrow stromal cells can induce partial differentiation of NG108-15 cells.     

Genomic organization and refined mapping of the mouse beta-dystrobrevin gene

beta-Dystrobrevin, a dystrophin-related protein that is expressed in non-muscle tissues, is highly homologous to alpha-dystrobrevin, a member of the dystrophin-associated protein complex (DPC). beta-Dystrobrevin associates with Dp71 and syntrophin and is believed to have a role in non-muscle DPCs. Here we report the characterization and mapping of the mouse beta-dystrobrevin gene. The mouse beta-dystrobrevin gene is organized into 21 exons spanning over 130 kb of DNA. We provide evidence that this gene is transcribed from at least two promoter regions but appears to utilize a common translation initiation site. We show that the similarity between beta-dystrobrevin and alpha-dystrobrevin is reflected in the conservation of their exon-intron junctions. beta-Dystrobrevin has been localized to proximal mouse Chromosome (Chr) 12 by backcross mapping. A database search revealed that two mouse genetic diseases involving tissues expressing beta-dystrobrevin have been mapped to this region, namely, congenital polycystic kidneys (cpk) and fatty liver dystrophy (fld). However, refined mapping analysis has excluded beta-dystrobrevin as a candidate gene for either disease.     

Immunochemical characterization of the deficiency of the alpha-ketoglutarate dehydrogenase complex in thiamine-deficient rat brain

Mitochondrial dysfunction is a common feature of many neurodegenerative disorders. The metabolic encephalopathy caused by thiamine deficiency (TD) is a classic example in which an impairment of cerebral oxidative metabolism leads to selective cell death. In experimental TD in rodents, a reduction in the activity of the thiamine diphosphate-dependent, mitochondrial enzyme alpha-ketoglutarate dehydrogenase complex (KGDHC) occurs before the onset of pathologic lesions and is among the earliest biochemical deficits found. To understand the molecular basis and the significance of the deficiency of KGDHC in TD-induced brain damage, the enzyme activity and protein levels of KGDHC were analyzed. The effect of TD on the subregional/cellular distribution of KGDHC and the anatomic relation of KGDHC with selective cell death were also tested by immunocytochemistry. Consistent with several previous studies, TD dramatically reduced KGDHC activity in both anatomically damaged (thalamus and inferior colliculus) and spared (cerebral cortex) regions. Immunocytochemistry revealed no apparent correlation of regional KGDHC immunoreactivity or its response to TD with affected regions in TD. The basis of the enzymatic and immunocytochemical behavior of KGDHC was further assessed by quantitative immunoblots, using antibodies specific for each of the three KGDHC components. Despite the marked decrease of KGDHC activity in TD, no reduction of any of the three KGDHC protein levels was found. Thus, TD impairs the efficacy of the KGDHC catalytic machinery, whereas the concentration of protein molecules persists. The generalized decline of KGDHC activity with no apparent anatomic selectivity is consistent with the notion that the compromised mitochondrial oxidation sensitizes the brain cells to various other insults that precipitate the cell death. The current TD model provides a relevant experimental system to understand the molecular basis of many neurodegenerative conditions in which mitochondrial dysfunction and KGDHC deficiency are prominent features.     

Rapid cloning of mouse DNA as yeast artificial chromosomes by transformation-associated recombination (TAR)

The purpose of this study is to investigate the count-characteristics of wrist actigraphy in basic human activities and to discuss the agreement of sleep-wake identification between polysomnography (PSG) and wrist actigraphy during nocturnal sleep. There was a distinct distribution of actigraphy counts over the studied activities. The evaluation of sleep-wake scoring using the wrist actigraphy agreed 96.9% with the polysomnographic scoring during nocturnal sleep.     

Experimental gastrocarcinogenesis: the dynamics of morphological and biochemical changes

Nebulization of lignocaine is a common technique for preparing the airway prior to awake intubation. The aim of the study was to assay the serum levels of lignocaine. Ten ASA I volunteers had 6 mg/kg of 10% lignocaine solution nebulized via facemask. Blood assays for peak levels were performed. Mean peak serum lignocaine level was 0.29 mg/l with a highest measurement of 0.45 mg/l. This peak occurred 30 minutes following commencing nebulization. No subject developed symptoms or signs of lignocaine toxicity. Peak plasma lignocaine levels were an order of magnitude below the accepted toxic threshold of 5 mg/l. This indicates that supplemental doses of lignocaine via the bronchoscope can be given with safety.     

A case of fracture of a ceramic head in total hip arthroplasty

We report a case of fracture of a ceramic femoral head, which spontaneously occurred 4 years after implantation of an uncemented total hip replacement in a 48-year-old male patient with avascular necrosis of the hip. At revision surgery, the fractured ceramic head was replaced with a 32-mm metallic femoral head.