Apolipoprotein E genotype influences cognitive ''phenotype'' in patients with Alzheimer''s disease but not in healthy control subjects

The effects of eicosanoids and of inhibitors of eicosanoid synthesis on the migration of third-stage larvae (L3) of Oesophagostomum dentatum were studied in an in vitro migration assay procedure. The L3 were incubated with diethylcarbamazine (DEC), indomethacin (INDO) or acetylsalicylic acid (ASA). Incubation with these inhibitors of eicosanoid metabolism resulted in a dose-dependent reversible inhibition of migration. The antimigratory effect of DEC could be completely reversed by treatment of the L3 with the lipoxygenase (LOX)-products leukotriene (LT) B4 or LTC4. LTD4 had a less distinct but similar effect, while LTE4 failed to reverse migration inhibition. Treatment with combinations of cyclooxygenase (COX)-products (prostaglandin, PG) partially restored the migration ability of ASA-treated L3, while PGD2, PGE2, PGF2 alpha or PGI2 exerted no distinct effect on ASA-treated L3 when given separately. The suppression of L3 migration by compounds that are known as antagonists of eicosanoid synthesis and the stimulation of migration of inhibitor-treated L3 by simultaneous application of eicosanoids indicate that these lipid mediators may play a significant role in physiological processes that interact with worm motility.     

Antiviral properties of 3-quinolinecarboxamides: a series of novel non-nucleoside antiherpetic agents

Despite the long history in medicine, the pathophysiological mechanism(s) of seasonal affective disorder (SAD) remain largely unknown. By employing a meta-analytic methodology, the authors of this study attempted to verify the validity of different pathophysiological mechanism(s) proposed for SAD. The findings showed that for phototherapy of medium light intensity, a combination of morning-evening therapy regime yielded the best therapeutic effect, and the antidepressant effect of the morning-evening light regime was superior to a single pulse of light administered at other times of day. Furthermore, the data showed that the antidepressant effect of a single pulse of light was similar for morning, midday, and evening light. These findings supported the photon-count hypothesis and refuted the proposed photoperiod, melatonin, and phase-shifting models of SAD.     

裸眼取换套管工艺的研究及应用

裸眼取换套管工艺是随着油水井老井及腐蚀损坏而开展的一项新的工艺技术。钻井二公司运用该项技术成功地取换修复了因套管腐蚀老化而停产的５口油水井。在取换套管施工过程中，对工具的配套准备、套管割铣工艺及套管回接技术等进行了应用研究，取得了良好的效果。５口井经试压达到了甲方设计要求的，均已恢复了注水及采油生产。     

Effects of efferent neurotransmitter acetylcholine and cochlear active substance ATP on cochlear outer hair cells

Toxoplasma antibody serological tests were carried out using the Dye test on sera of pregnant and postpartum Nigerian women to investigate whether there was any association between the levels of antibody titres and the occurrence of stillbirths and congenital malformations. There was a high prevalence of toxoplasma antibodies in the sera of both pregnant and postpartum women. The prevalence rates for the pregnant women ranged from 72.5% to 88.8% with an overall rate of 75.4%; whilst for the postpartum women, the prevalence rates ranged from 75.0% to 94.4% with an overall rate of 80.5%. The toxoplasma antibody titres of the sera from the live-born babies as well as stillbirths and congenitally malformed babies ranged from 1:16 to 1:1024. The exact role played by toxoplasma in the occurrence of stillbirths and congenital malformation in our area of study is, however, not clear. For future research, it is suggested that larger samples be studied in order to enhance the validity of the findings of the present study.     

Absence of contour linking in peripheral vision

Human foveal vision is subserved initially by groups of spatial, temporal and orientational 'filters', the outputs of which are combined to define perceptual objects. Although a great deal is known about the filtering properties of individual cortical cells, relatively little is known about the nature of this 'linking' process. One recent approach has shown that the process can be thought of in terms of an association field whose strength is determined conjointly by the orientation and distance of the object. Here we describe a fundamental difference in this feature-linking process in central and peripheral parts of the visual field, which provides insight into the ways that foveal and peripheral visual perception differ. In the fovea, performance can be explained only by intercellular linking operations whereas in the periphery intracellular filtering will suffice. This difference represents a substantial economy in cortical neuronal processing of peripheral visual information and may allow a recent theory of intercellular binding to be tested.     

Localization of neutral endopeptidase in the ovine uterus and conceptus during the oestrous cycle and early pregnancy

Allylamine (AA) is an electrophilic amine with a long history of experimental usage because of its extremely potent and relatively specific cardiovascular toxicity; it has been utilized in a variety of experimental models attempting to mimic human atherosclerotic lesions, myocardial infarction, and vascular injury. Even though the exact mechanisms by which AA causes vascular lesions remain unresolved, recent studies on the acute effects of AA exposure in rats strongly suggest that deamination to the aldehyde acrolein, oxidative stress, and the resultant increase in lipid peroxidation, generation of .OH radicals, and acute depletion of glutathione (GSH) may be some of the causative factors in AA-induced vascular lesions. Since glutathione S-transferase 8-8 (GST8-8) of rat belongs to a distinct subgroup of GST isozymes involved in the detoxification of products of lipid peroxidation, we designed studies to examine the effects of AA exposure on this GST isoform in rat aorta using Western blotting and immunohistochemical techniques. The results of these studies demonstrate that GST8-8 is expressed in rat aorta and is dramatically induced upon AA exposure. By immunohistochemistry, GST8-8 was localized in the smooth muscle cells of the vascular media which is believed to be the site of metabolism of AA. A significant increase in gamma-glutamylcysteine synthetase activity and GST activity toward 4-hydroxynonenal and acrolein, which are preferred substrates of GST8-8, was seen as early as 3 days following AA treatment. Alterations in GSH and other GSH-related enzymes at 3 and 10 days support the concept that--upon AA exposure--aortic defense mechanisms respond early and induction of GSH biosynthesis and rat GST8-8 occur to alleviate the toxic effects of acrolein, a major, genotoxic product of AA metabolism. The presence of GST8-8 in the vasculature, which is constantly exposed to products of lipid peroxidation, and its induction by AA, suggest that GST8-8 plays a key role in protecting blood vessels against oxidative stress and hence, may be involved in the atherogenic process.     

Functional NMDA receptors are transiently active and support the survival of Purkinje cells in culture

Conflicting evidence exists concerning the activity of NMDA receptors (NMDARs) in cerebellar Purkinje cells and their possible functions. To investigate the activity of NMDARS, we used whole-cell recording on immunocytochemically identified Purkinje cells in primary culture. In addition, we used mice with a disrupted NMDAR1 gene that lack functional NMDARs (NR1-/-) to assess the physiological role of NMDARs. In cultures from normal mice, NMDA-medicated currents were detected in all identified Purkinje cells at 4 d in vitro (div). After 14 d, however, NMDA responses were reduced in amplitude, whereas the responses to kainate and glutamate increased steadily in amplitude. In addition, the NMDA-induced current displayed a pronounced desensitization at these later stages; peak current declined to zero during steady application of NMDA. At 7 div, the number of surviving Purkinje cells was less in cultures treated with NMDA antagonists, and their survival was dose-dependent. Purkinje cell survival was correspondingly poorer in cultures from the NR1-/- mice than in wild-type controls, suggesting that NMDAR activity enhances the survival of Purkinje cells in vitro. The addition of moderate doses of NMDA promoted the survival of wild-type Purkinje cells in the presence of tetrodotoxin. Feeder layers of cerebellar granule cells derived from wild-type or NR1-/- mice promoted survival of Purkinje cells to a similar degree, suggesting that the NMDAR in Purkinje cells, but not in other cells, is directly involved in Purkinje cell viability. The results demonstrate that NMDARs transiently produce membrane current in Purkinje cells and may serve as one of the epigenetic factors that support the survival of Purkinje cells in vitro.     

Clinical features of tuberculosis associated with HIV infection in Taiwan

To understand the clinical characteristics and outcome of tuberculosis (TB) in patients with acquired immunodeficiency syndrome (AIDS) in Taiwan, we reviewed the medical records of 118 adult AIDS patients who were hospitalized at National Taiwan University Hospital between January 1988 and September 1995. Among them, 29 (24.6%) had TB. The mean age of the AIDS patients with TB was 37 years (range, 25-66 yr). Most patients were in the advanced stages of AIDS when human immunodeficiency virus (HIV) infection and/or TB were first diagnosed. The mean CD4+ lymphocyte count was 0.037 x 10(9)/L (range, 0-0.152 x 10(9)/L) at the time TB was diagnosed. There was no statistically significant difference in the mean CD4+ lymphocyte count between patients with isolated pulmonary TB and those with extrapulmonary involvement. Twenty-two patients (75.8%) had extrapulmonary TB with the most common site being the lymph nodes (72.7%). Clinical symptoms were nonspecific, and the chest physical examination was not helpful in the diagnosis. Acid-fast bacilli were detected in sputum smears from eight patients (36.4%). A primary tuberculosis pattern (hilar adenopathy, pleural effusion, middle or lower lobe infiltrates) in the chest radiographs was the most common radiologic finding (36.4%) in patients with pulmonary TB. The reactivation pattern (predominant upper-lobe infiltrates with or without cavitation) could only be found in cases of pulmonary TB without extrapulmonary involvement. Atypical patterns (diffuse interstitial infiltrates mimicking Pneumocystis carinii pneumonia or other patterns) and normal chest radiographs were noted in nearly one-third of the patients with pulmonary TB. A good response to antituberculosis drugs and a favorable outcome were demonstrated in the patients, except for two with drug-resistant Mycobacterium tuberculosis infection. Early identification of TB in HIV-infected patients requires clinical awareness of the unusual clinical presentations, especially among patients in the advanced stages of AIDS.