0～2岁儿童低血红蛋白与铅中毒对智能发育的影响

目的:了解铅中毒、低血红蛋白对儿童智能发育的影响及相关性。方法:在城区初级保健门诊随机对201例0~2岁儿童检测血铅、血红蛋白及发育指数。采用CDCC量表,通过智力发育指数(MDI)、心理运动发育指数(PDl)评估儿童智商状况。结果:血铅≥100μg/L32例,占15.92%,其MDI均值为(94.18±9.49),PDI均值为(91.43±10.70)。正常对照组MDI均值为(106.18±16.24),PDI均值为(94.42±12.55),两组相比智力发育有明显差异。血红蛋白≤110 g/L 24例,占11.94%,均为轻度贫血,其MDI为(102.25±16.50),PDI为(88.95±11.33),两项指标均为低水平,但差异不显著。结论:与轻度贫血相比,铅中毒更能导致婴幼儿智力发育落后,低浓度铅中毒与贫血相关性尚不明显。【关键词】血红蛋白铅中毒婴幼儿智能发育     

Residues of Polychlorinated Biphenyls（PCBs）in Fish,Water and Sediment from Shing Mun River

The level and pattern of contamination by polychlorinated biphenyls (PCBs) were investigated in tilapia, Oreochromis mossambicus (Peters), sediment, and water from the Shing Mun River. The range of total PCBs was 12.9 ng/g to 181.6 ng/g wet weight in tilapia, 12.7 ng/g to 46.0 ng/g freeze-dried weight in sediment, and 3.8 ng/L to 13.6 ng/L in water. The effect of biomagnification was also observed, PCB concentrations increased from water to sediment to tilapia. PCB congeners occurred in such a way that lower chlorinated PCBs comprised a higher fraction of the total PCBs in water, sediment, and tilapia muscle, whereas higher chlorinated PCBs were more commonly found only in tilapia.     

Neuronal loss is greater in the locus coeruleus than nucleus basalis and substantia nigra in Alzheimer and Parkinson diseases

CONTEXT: Alzheimer disease (AD) and Parkinson disease (PD) are associated with neuronal degeneration in major subcortical nuclei, but few studies have examined the neuronal degeneration in these nuclei concurrently. OBJECTIVE: To identify clinical and pathological correlates of neuronal loss in the nucleus basalis (NB), locus coeruleus (LC), and substantia nigra pars compacta (SN) in AD and PD. DESIGN: The study sample comprised 86 cases with pathologically confirmed AD, 19 cases with PD, and 13 healthy elderly control subjects. The number of nucleolated neurons was counted in representative sections of the NB, LC, and SN. Effect sizes (ES) were computed to determine the standardized difference in cell counts relative to healthy controls. RESULTS: Cases of AD showed the greatest neuronal loss in the LC (ES = 3.16) followed by the NB (ES = 1.10), but variable loss in the SN (ES = 0.16). Cases of PD also showed the greatest neuronal loss in the LC (ES = 6.47), followed by the SN (ES = 2.58) and the NB (ES = 0.85). Significant correlations were found between the number of neurons in the NB and LC in PD (r = 0.54, P<.05), as well as AD (r = 0.24, P<.05). The duration of illness correlated with greater neuronal loss in the LC and NB in AD, and greater neuronal loss in the SN in PD. CONCLUSIONS: For both AD and PD the greatest neuronal loss was found in the LC. In AD, neuronal loss was most severe and best correlated with the duration of illness in the LC, rather than in NB as traditionally expected. Correlations between neuronal loss in the LC and NB (but not SN) in both PD and AD suggest that the former 2 nuclei may share common pathogenetic susceptibilities. Given the prominent loss of neurons in the LC, detection and treatment of noradrenergic deficiencies warrant attention in both AD and PD.     

早期蔺草尘肺的HRCT表现

目的：研究早期蔺草尘肺的HRCT表现。方法：对经高kVp胸片筛选后的47例蔺草作业工人作胸部HRCT扫描并分析CT表现,其中包括25例已被确诊尘肺和22例未能确诊尘肺者。结果：44例显示弥漫性分布的类圆形“P”小结节阴影,包括高kVp胸片尚难以确诊蔺草尘肺的22例,3例上肺野出现大阴影及间质性纤维化。结论：早期的蔺草尘肺结节在肺小叶内呈随机分布,并非仅在小叶中心,细支气管壁和小叶间隔未见增厚,HRCT对显示弥漫性尘肺结节灶及肺间质性改变明显优于胸片。     

Volumetric MRI predicts rate of cognitive decline related to AD and cerebrovascular disease

OBJECTIVE: To examine volumetric MRI correlates of longitudinal cognitive decline in normal aging, AD, and subcortical cerebrovascular brain injury (SCVBI). BACKGROUND: Previous cross-sectional studies examining the relationship between cognitive impairment and dementia have shown that hippocampal and cortical gray matter atrophy are the most important predictors of cognitive impairment, even in cases with SCVBI. The authors hypothesized that hippocampal and cortical gray matter volume also would best predict rate of cognitive decline in cases with and without SCVBI. METHODS: Subjects were recruited for a multicenter study of contributions to dementia of AD and SCVBI. The sample (n = 120) included cognitively normal, cognitively impaired, and demented cases with and without lacunes identified by MRI. Cases with cortical strokes were excluded. Average length of follow-up was 3.0 years. Measures of hippocampal volume, volume of cortical gray matter, presence of subcortical lacunes, and volume of white matter hyperintensity were derived from MRI. Random effects modeling of longitudinal data was used to assess effects of baseline MRI variables on longitudinal change in a measure of global cognitive ability. RESULTS: Cortical gray matter atrophy predicted cognitive decline regardless of whether lacunes were present. Hippocampal atrophy predicted decline only in those without lacunes. Neither lacunes nor white matter hyperintensity independently predicted decline. CONCLUSIONS: Results suggest that cortical atrophy is an index of disease severity in both AD and subcortical cerebrovascular brain injury and consequently predicts faster progression. Hippocampal volume may index disease severity and predict progression in AD. The absence of this effect in cases with lacunes suggests that this group is etiologically heterogeneous and is not composed simply of cases of AD with incidental stroke.     

Establishment of a simple assay in vitro for hepatitis C virus NS3 serine protease based on recombinant substrate and single—Chain protease

AIM: To establish a simple and convenient assay in vitro for the Hepatitis C virus NS3 serine protease based on the recombinant protease and substrate, and to evaluate its feasibility in screening the enzyme inhibitors. METHODS: Based on the crystallographic structure of hepatitis C virus (HCV) serine protease, a novel single-chain serine protease was designed, in which the central sequence of cofactor NS4A was linked to the N-terminus of NS3 serine protease domain via a flexible linker GSGS. The fusion gene was obtained by two-step PCR that was carried out with three primers and then cloned into the prokaryotic expression vector pQE30, and the recombinant clone was verified by DNA sequencing. The single-chain recombinant protease was expressed when the E.coli was induced with IPTG and the expression conditions were optimized to produce large amount of soluble protease. The recombinant substrate NS5ab that covers the cleavage point NS5A/B was also expressed in E.coli. Both of the protease and substrate were purified by using Ni-NTA agarose metal affinity resin, then they were mixed together in a specific buffer, and the mixture was analyzed by SDS-PAGE. The cleavage system was used to evaluate some compounds for their inhibitory activity on serine protease. RESULTS: The single-chain recombinant protease was over-expressed as soluble protein when the E.coli was induced at a low dosage of IPTG (0.2 mM) and cultured at a low temperature (15 degrees ). The protease was purified by using Ni-NTA agarose metal affinity resin (the purity is over 95 %). The recombinant substrate NS5ab was expressed in an insoluble form and could refold successfully after purification and dialysis. A simple and convenient assay in vitro was established, in which the purified single-chain serine protease could cleave the recombinant substrate NS5ab into two fragments that were visualized by SDS-PAGE. PMSF had an effect on inhibiting activity of serine protease, while EDTA had not. CONCLUSION: A simple and convenient assay in vitro for hepatitis C virus NS3 serine protease is based on recombinant substrate NS5ab and single-chain serine protease. This assay can be used in screening of enzyme inhibitors.