Testing genetic models for multiple symptoms: An application to the genetic analysis of liability to depression

A model is presented which allows for the contribution of genes and environment to categorical data on multiple symptoms. The model distinguishes between parameters needed to express the relationship between a latent trait and observed responses and the parameters required to represent the causes of variation in the latent trait. The regression of the latent trait on covariates may also be specified. The model is applied to symptoms of depression in 1983 pairs of adult female monozygotic and dizygotic twins. A model which allows only for polygenic variation in the latent trait is supported as well as the mixed model, which also allows for the effects of a major gene. The likelihood is significantly lower when all genetic effects are ascribed to a single gene. Practical limitations of the method are discussed.This research is supported by Grants AG04954, AA06781, GM32782, GM30250, and MH40828 from the National Institutes of Health. We are indebted to Dr. Greg Carey for his incisive discussion.     

Renal glomerulogenesis in medaka fish, Oryzias latipes

We provide an overview of glomerulogenesis in medaka from the embryo to the adult by means of in situ hybridization with the wt1 gene as a marker as well as histology and three-dimensional images. The pronephric glomus starts to develop in the intermediate mesoderm during early somitogenesis, is completed before hatching, and persists throughout the lifetime of the fish. Within 5 days after hatching, mesonephric glomerulus formation begins in the caudomedial end of the pronephric sinus and duct area. The number of glomeruli reaches approximately 200-300 in each kidney within 2 months after hatching. wt1 expression during nephron maturation served as a marker for the formation of the mesenchymal condensate and the nephrogenic body. Existence of mesenchymal condensates and persistence of wt1 expression in the adult kidney suggest that the mesonephros retains precursor cells that may be capable of contributing to neoglomerulogenesis during adulthood. Developmental Dynamics 237:2342-2352, 2008. (c) 2008 Wiley-Liss, Inc.     

The effects of thermochemotherapy using cyclophosphamide plus hyperthermia on the malignant pleural mesothelioma in vivo

The human malignant pleural mesothelioma is related to the use of asbestos in the majority of cases. Though the use of asbestos has been prohibited since the 1990s, the incidence of pleural mesothelioma is still increasing because of a latency period of at least 20 years. This study investigated the benefit of single therapy with cyclophosphamide or hyperthermia or the combination of both on cells of a human pleural mesothelioma cell line, xenotransplanted subcutaneously in the paw of mice. A CONTROL group received the same volume of physiological saline. The oxygenation of tumours was measured, tumour growth was followed over 3 weeks, immunohistochemical studies and a light and electron microscopic evaluation were performed. Chemotherapy or hyperthermia alone was only temporarily effective. The greatest benefit was achieved using combined thermochemotherapy consisting of cyclophosphamide plus hyperthermia: 50% of this group had partial remissions, and 67% responded to this therapy. After 3 weeks tumours grew again. Superior effects could be achieved by performing additional cycles of chemotherapy or adding another drug or radiation for instance. This study shows promising results in the treatment of malignant pleural mesothelioma.     

材料参数与镍钛形状记忆合金的本构关系

在Ｔａｎａｋａ模型基础上，我们讨论了形状记忆合金热力学特性的本构关系。特别注意了桓温拉伸过程和强迫回复过程。本构方程的材料参数，即弹性模量Ｄ，变化张量Ω，热力弹性张量均以镍钛合金实验测试值来确定。在不同的应力－应变－温度关系试验中发现Ｄ和Ω与温度之间有很强的相关性。     

Patient-ventilator interaction: A general model for nonpassive mechanical ventilation

A general mathematical model for the dynamic behaviour of asingle-compartment respiratory system in response to an arbitraryapplied inspiratory airway pressure and arbitrary respiratorymuscle activity is investigated. The model is used to computeexplicit expressions for ventilation and pressure variablesof clinical interest for clinician-selected and impedance-determinedinputs. The outcome variables include tidal volume, end-expiratorypressure, minute ventilation, mean alveolar pressure, averagepleural pressure, as well as the work performed by the ventilatorand the respiratory muscles. It is also demonstrated that undersuitable conditions, there is a flow reversal that can occurduring inspiration.     

Psychopathology and Public Policy

An effective definition of psychopathology would be helpful in distinguishing between normal and abnormal behavior and would provide guidance for important public policy decisions. Overinclusive definitions, such as the capacity/disability formulation, do not provide meaningful direction for defining need or assessing eligibility for insurance or other entitlements. Coping failures due to lack of skill, inadequate preparation, or other factors should be distinguished from those due to dysfunction or disturbance of psychological mechanisms. The capacity/disability formulation encourages confusion between different performance decrements and gives no guidance for appropriate boundaries for psychotherapy.     

Interpretation of venous occlusion plethysmography using a nonlinear model

Venous occlusion plethysmography (VOP) is a noninvasive technique widely employed for the detection of deep-vein thrombosis. Previous reports that VOP outflow curves are closely fit by a first-order exponential suggest that venous compliance and resistance are nearly constant. Typically, however, the venous compliance function has a sigmoid shape; in addition, the resistance in a collapsing tube must increase. This paradox was resolved by the surprising finding that for realistic nonlinear compliance and resistance these nonlinearities cancel, producing a quasilinear venous outflow that approximates a simple exponential.     

Theoretical analysis of surface EMG in voluntary isometric contraction

Summary A new stochastic model of the surface EMG is suggested and the spectral density of the surface EMG is studied theoretically and experimentally to confirm the validity of this model.Theoretical results show that while the contraction level is not so high, the shape of the spectral density (distribution) does not change and its amplitude is directly proportional to the motor unit firing frequency and recruitment.To illustrate the theoretical results, experiments were carried out for rectus femoris and biceps brachii. The surface EMG was lead off by bipolar surface electrodes. And the spectral density of the surface EMG was calculated using FFT algorithm.From these experimental results, it was confirmed that our theoretical results were almost valid.     

钴60放射法制备免疫功能抑制大鼠模型

目的通过系统的钴60放射计划,对大鼠免疫功能抑制的合适剂量进行评估,为干细胞移植研究提供合适的的动物模型。方法SD大鼠随机分为12.5Gy、10Gy、7.5Gy、5Gy4个剂量组,10只/组。计算放射后2个月的死亡率。检测白细胞数量,评价各剂量组动物的白细胞参考值范围。结合死亡率和白细胞参考值范围,确定合适的放射剂量。通过对外周血中性粒细胞(PMN)吞噬实验和外周血白细胞移行抑制实验(MIT),对细胞免疫功能进行检测。结果行12.5Gy照射的大鼠,3d内全部死亡;10Gy放射后的大鼠在1个月内全部死亡;7.5Gy照射的大鼠2个月内死亡1只;5Gy照射的大鼠没有死亡情况发生。设定95%作为可信区间,计算白细胞数量参考值范围(109个/L),未放疗组:16.978+1.96×6.46;5Gy放疗组:4.93+1.96×0.72;7.5Gy放疗组:2.313+1.96×0.782;10Gy放疗组:1.03+1.96×0.507。t检验表明,随着放疗剂量的增加,各实验组的白细胞数量显著减少。对于细胞免疫功能的检测,外周血中性粒细胞(PMN)吞噬实验结果表明,机体全身免疫功能降低;外周血白细胞移行抑制实验(MIT)表明,机体T细胞免疫功能降低。结论7.5Gy可以一定程度上抑制大鼠的免疫功能,为合适的放疗剂量。