Comparison of Marker Intervals and Number of Sib Pairs Used for Linkage Analysis on Simulated Nuclear Family Data

Using a two‐stage global scan design, we analyzed general population replicates 1 and 42 of the Genetic Analysis Workshop (GAW) 12 simulated data set using three methods: revisited Haseman‐Elston (HER), maximum likelihood variance estimation (ML), and variance components (VC). Three marker densities, 5‐, 10‐, and 15‐cM intervals, were examined in the first‐stage scan. We found that the 10‐cM interval appears to be the most cost‐effective approach in genotyping without sacrificing power when using a first stage significance level of 0.01. Subsequently, we performed the second‐stage scan at 1‐cM intervals for those putative positive regions identified in the first‐stage scan at a significance level of 0.01. We also compared the power to detect linkage using different numbers of sib pairs for a genome‐wide scan at a 10‐cM interval and found that power decreases nonlinearly as the number of sib pairs decreases. © 2001 Wiley‐Liss, Inc.     

Numerical data on neocortical neurons in adult rat, with special reference to the GABA population

The disector method was used to estimate the numerical density of neurons (number per unit volume) and their actual number per column (number under a given area of pial surface), in the occipital (monocular segment of the primary visual area, Oc1M), the parietal (somatosensory barrelfield area, Par1) and the frontal cortex (primary motor area, Fr1) of adult rat. Values were first obtained for all neurons in each layer, and then for GABA neurons as identified with postembedding immunocytochemistry on semithin sections. The numerical density of neurons in the frontal cortex (34,000/mm³) was significantly lower than in the two other neocortical areas (occipital: 52,000; parietal: 48,000/mm³). The GABA population showed a similar difference and consequently represented an equivalent proportion of total (15%) in the three cortical areas. Across layers, there was an alternate distribution of low and high density of neurons from layers II–III to VI in the three cortical areas, with the highest density in layer IV of the two sensory areas. The laminar changes in density of the GABA neurons were not as pronounced as those of the overall population. Consequently, the layers with the highest overall neuronal densities tended to have a lower proportion of GABA neurons and vice versa. There were more neurons under 1 mm² of surface in the parietal (90,000) than the occipital or the frontal cortex (71,000), which was also true of the GABA neurons. The greater number of neurons per column in the parietal cortex was mostly imputable to layer IV, the main recipient of thalamic axons. Comparing these values from the rat with those previously obtained in cat and monkey, it seemed that the number of neurons per cortical column was the highest in the sensory area preferentially used by each species.     

全国部分城乡家鼠鼠情监测三年结果分析——Ⅰ.鼠种组成及地区分布

对全国部分城乡家鼠鼠情监测三年结果的分析表明:城乡家鼠组成均以三大家鼠(褐家鼠、小家鼠、黄胸鼠)为主,其次为食虫目臭鼩鼱~#和黑线姬鼠。五种主要鼠种在家鼠组成中的数量比基本稳定,但三年中城乡少数鼠种间的顺位有所变化。监测结果亦表明,五种主要鼠种的地区分布是:褐家鼠、小家鼠遍布所有监测的省、市、区,同以往文献中遍布全国的说法一致;黄胸鼠分布于黄河以南;食虫目中的臭鼩鼱分布于华中区以南的广大地区。这在以往文献中均已有记载,但以往文献有关黄胸鼠和臭鼩鼱分布的其他说法,则被证实为不确切的。黑线姬鼠的分布范围已超过以往文献中关于分布于东北、华北及长江流域的说法,但以往文献中关于该鼠种遍及全国的说法是否正确,则有待进一步证实。     

The accuracy of volumetric bone density measurements in dual X-ray absorptiometry

New developments in dual x-ray absorptiometry (DXA) allow the performance of high precision anteroposterior (AP) and lateral scans of spinal bone mineral density (BMD, units: g/cm²) without the patient moving from the supine position. Data from both projections may be combined to give an estimate of the true volumetric bone mineral density (VBMD, units: g/cm³) of the lumbar vertebral bodies. This report presents a cadaver study designed to validate DXA measurements of volumetric bone density. Sections of whole lumbar spine were scanned in AP and lateral projections in a water tank to simulate soft tissue. Individual vertebrae were then divided to separate the vertebral body from the neural arch, and vertebral body volume was measured using the displacement of sand. The bone mineral content (BMC) of vertebral bodies and neural arches was measured by ashing at 250°C for 60 hours followed by 500°C for a further 24 hours. The results showed that DXA scanning systematically underestimated ashing data by 14% for AP BMC, 33% for vertebral body BMC, 23% for vertebral body volume, and 12% for VBMD. Despite these significant systematic errors, the DXA measurements and ashing values were highly correlated (r=0.979-0.992). The results suggested that after allowing for the systematic errors, lateral DXA parameters related closely to true BMC, volume, and VBMD.     

High Cell-Density Culture System of Hepatocytes Entrapped in a Three-Dimensional Hollow Fiber Module with Collagen Gel

Abstract: A compact three-dimensional (3D) module is needed for hepatocyte culture in order to develop an effective hybrid artificial liver system that can retain hepa-tocellular structure and differentiated functions. We treated the 3D module with collagen gel to entrap rat hepatocytes. This method yielded a high hepatocellular density (2 times 10⁷ cells/ml) over a period of 14 days and maintained the secretion of albumin and ureogenesis at the same level as the control monolayer method. The ammonia removal remained at 43% of the Day 0 value over 8 days of perfusion. Our data show that this approach may be useful for liver support therapy in an ex-tracorporeal circuit.     

Ex vivo estimation of thoracolumbar vertebral body compressive strength: The relative contributions of bone densitometry and vertebral morphometry

The estimation of vertebral fracture risk in individuals with suspected osteopenia is commonly based on measurements of lumbar spine bone density. The efficacy of vertebral size and deformity, as assessed by vertebral morphometry, in the prediction of fractures has been less studied. In an ex vivo investigation the regional relationships between vertebral size, vertebral deformity, bone density and compressive strength throughout the thoracolumbar spine were examined. In 16 vertebral columns (T1–L5) the bone mineral content (BMC) and bone mineral density (BMD) of each segment were measured using lateral projection dual-energy X-ray absorptiometry, and the vertebral cancellous density (VCD) and mid-vertebral cross-sectional area (CSA) measured using quantitative computed tomography. Vertebral body heights were determined from mid-sagittal CT scans, and vertical height ratios calculated for each segment. The failure load and failure stress of the isolated vertebral bodies were determined using a material testing device. Separate analyses were performed for the upper (T1–4), middle (T5–8) and lower (T9–12) thoracic, and lumbar (L1–5) segments. In all regions, failure load was strongly correlated with BMD (r=0.82–0.86), moderately correlated with VCD (r=0.60–0.71) and vertebral height (r=0.22–0.49), and poorly correlated with the height ratios (r=0.04–0.33). Failure stress was best predicted by BMD (r=0.73–0.78) and VCD (r=0.70–0.78) but was poorly correlated with all morphometric variables (r=0.01–0.33). The segmental correlations between BMD and VCD ranged fromr=0.49 tor=0.79. For all regions, BMD and VCD were included in the stepwise regression models for predicting failure load and failure stress. Either the mid-vertebral height or CSA were included in all the failure load models, while mid-vertebral height was included in only one of the failure stress models. The results suggest that vertebral deformity and size (as assessed by vertebral morphometry) make only a minor contribution to the prediction of vertebral strength additional to that provided by bone densitometry alone. The consistent regional relationships between variables appear to support the practice of global fracture risk assessment based on lumbar spine densitometry.     

砀山县2001年肾综合征出血热疫源地主要宿主调查分析

目的:探讨砀山县肾综合征出血热(EHF)的宿主动物,明确主要传染源种类,为预防和控制EHF的发生与流行,给制订防治对策提供科学依据。方法:根据地理景观特点选择近几年疫情较重的黄楼、关帝庙为调查点,用夹夜法进行鼠密度、种类调查,对捕获的鼠检测EHF抗原、抗体,同时对健康人群用间接免疫荧光法(IFA)检测EHF抗体。结果:室内外平均鼠密度为4.14%(63/1520),室内以小家鼠(占60.0%)、室外黑线姬鼠(占70.8%)为优势鼠种;鼠肺EHF带毒率为1.59%(1/63)、鼠血EHF抗体阳性率为7.94%(5/63),健康人群EHF抗体阳性率为3.7%(2/54)。结论:鼠类有1目2科6种鼠,另有食虫目鼠句鼠青科的臭鼠句鼠青;黑线姬鼠为砀山县EHF的主要宿主动物,健康人群血清学调查证实有隐性感染存在。     

原发性食管癌中胸苷磷酸化酶表达和血管生成的临床意义

目的　观察原发性食管癌中胸苷磷酸化酶 (thymidinephosphorylase,TP)的表达情况 ,探讨肿瘤组织中胸苷磷酸化酶表达、肿瘤微血管密度 (microvesseldensity ,MVD)和临床病理特征之间的关系 ,分析TP表达和肿瘤MVD的预后意义。方法　应用单克隆抗体对 6 5例食管癌标本进行免疫组化染色 ,测定TP表达及MVD。结果　TP在食管癌中的表达 (4 5 / 6 5 ,6 9.2 % )明显 (P <0 .0 0 1)高于正常食管粘膜 (4 / 2 4 ,16 .7% )。食管癌的MVD(4 5 .0 9± 8.76 )与正常食管粘膜的MVD(2 7.4 8± 8.4 4 )的差别显著 (P <0 .0 0 1)。食管癌TP阳性的MVD的均值是 (4 6 .5 3± 7.18) ,TP阴性的MVD的均值是 (4 1.85± 11.0 8) ,前者明显 (P =0 .0 4 6 ) 高于后者。食管癌的TP表达与临床病理特征无相关性 ,MVD却与肿瘤的浸润深度(P =0 .0 35 ) 及分期(P =0 .0 18) 有关 ,而且只有MVD才是食管癌的一个预后指标(P <0 .0 0 1)。结论　食管癌的TP表达与MVD密切相关。TP表达与食管癌的临床病理特征无关。MVD与肿瘤的浸润发展有关 ,同时只有MVD才是食管癌的一个预后指标     

The distribution profiles of very low density and low density lipoproteins in poorly-controlled male,Type 2 (non-insulin-dependent) diabetic patients

Summary The distribution and composition of lipoproteins spanning the very low density and low density lipoprotein spectra have been analysed in ten poorly-controlled, male, Type 2 (non-insulin-dependent), diabetic patients pre-disposed to mild, secondary hypertriglyceridaemia. As compared to age-matched control subjects, the diabetic patients displayed grossly modified, distinctly atherogenic lipoprotein profiles. Modifications were not limited to the very low density lipoprotein profile, as would be expected from the pre-treatment hypertriglyceridaemia. There was also an aberrant low density lipoprotein profile, which was not evident from plasma cholesterol measurements, especially as the diabetic patients at entry were well matched to control subjects with respect to plasma levels of this lipid. Compositional abnormalities were also observed in the poorly-controlled diabetic group, although these were less marked than the distributional changes. There were substantial improvements of the abnormalities detailed above, even over a short treatment period (two weeks), with therapy designed primarily to ameliorate metabolic control. The data suggest that, in the presence of poor metabolic control and hypertriglyceridaemia, occult, atherogenic modifications of low density lipoproteins can occur. The results argue in favour of strict control of triglyceride levels even in diabetic patients with apparently acceptable cholesterol levels.