Planning for smallpox outbreaks

Mathematical models of viral transmission and control are important tools for assessing the threat posed by deliberate release of the smallpox virus and the best means of containing an outbreak. Models must balance biological realism against limitations of knowledge, and uncertainties need to be accurately communicated to policy-makers. Smallpox poses the particular challenge that key biological, social and spatial factors affecting disease spread in contemporary populations must be elucidated largely from historical studies undertaken before disease eradication in 1979. We review the use of models in smallpox planning within the broader epidemiological context set by recent outbreaks of both novel and re-emerging pathogens.     

Deletion of brain dystroglycan recapitulates aspects of congenital muscular dystrophy

Fukuyama congenital muscular dystrophy (FCMD), muscle-eye-brain disease (MEB), and Walker-Warburg syndrome are congenital muscular dystrophies (CMDs) with associated developmental brain defects. Mutations reported in genes of FCMD and MEB patients suggest that the genes may be involved in protein glycosylation. Dystroglycan is a highly glycosylated component of the muscle dystrophin-glycoprotein complex that is also expressed in brain, where its function is unknown. Here we show that brain-selective deletion of dystroglycan in mice is sufficient to cause CMD-like brain malformations, including disarray of cerebral cortical layering, fusion of cerebral hemispheres and cerebellar folia, and aberrant migration of granule cells. Dystroglycan-null brain loses its high-affinity binding to the extracellular matrix protein laminin, and shows discontinuities in the pial surface basal lamina (glia limitans) that probably underlie the neuronal migration errors. Furthermore, mutant mice have severely blunted hippocampal long-term potentiation with electrophysiologic characterization indicating that dystroglycan might have a postsynaptic role in learning and memory. Our data strongly support the hypothesis that defects in dystroglycan are central to the pathogenesis of structural and functional brain abnormalities seen in CMD.     

New estimates of trends in births by birth order in England and Wales

A greater understanding of past, present and future trends in fertility can be gained from analysing trends in birth order; that is whether a birth is a first, second, third or higher order birth. However, under current legislation, birth order information is not collected at registration for births outside marriage and birth order recorded within marriage is not the true birth order. This article presents revised and updated estimates of true birth order. It discusses the construction of the new estimates and presents analysis relating the births by true birth order to the population of women by parity on both a period (fertility in a particular year) and cohort (fertility of women born in a particular year) basis. The new true birth order figures are also compared to the previous set of estimates.     

The Need for a Systemic Approach to Change Management—A Case Study

Change is now a constant feature of organizational life, but the effectiveness of change management initiatives is often open to question. By reflecting on a case of change management involving a Higher Education Institution (HEI), this paper argues that, to be more effective, organizational change must be managed systemically. The paper first provides a systemic conceptual underpinning to change management, and then examines the case by comparing what had really happened with what might have happened if organizational change had been managed systemically. The analysis helps build an improved understanding of change management, and provides implications for future change management practice.     

cDNA芯片技术和病毒感染的基因表达

论述了最近发展的ｃＤＮＡ芯片技术及其在基因的发现和表达以及在疾病诊断上的应用。该技术是把ｃＤＮＡ的阵列由高速自动控制仪器置于玻璃片上,用标记的探针测定互补结合的情况,可同时进行大量基因的表达和基因的发现研究。这是一个高效率和大规模的基因组分析和表达的研究技术。使用这一新技术,发现了ＨＩＶ感染期间ｈｓｐ７０基因表达发生的变化,传统的Ｎｏｒｔｈｅｒｎ分析证实了芯片的测定结果。综述中还包括了作者未作发表     

Direct control of paralysed muscles by cortical neurons

A potential treatment for paralysis resulting from spinal cord injury is to route control signals from the brain around the injury by artificial connections. Such signals could then control electrical stimulation of muscles, thereby restoring volitional movement to paralysed limbs. In previously separate experiments, activity of motor cortex neurons related to actual or imagined movements has been used to control computer cursors and robotic arms, and paralysed muscles have been activated by functional electrical stimulation. Here we show that Macaca nemestrina monkeys can directly control stimulation of muscles using the activity of neurons in the motor cortex, thereby restoring goal-directed movements to a transiently paralysed arm. Moreover, neurons could control functional stimulation equally well regardless of any previous association to movement, a finding that considerably expands the source of control signals for brain-machine interfaces. Monkeys learned to use these artificial connections from cortical cells to muscles to generate bidirectional wrist torques, and controlled multiple neuron-muscle pairs simultaneously. Such direct transforms from cortical activity to muscle stimulation could be implemented by autonomous electronic circuitry, creating a relatively natural neuroprosthesis. These results are the first demonstration that direct artificial connections between cortical cells and muscles can compensate for interrupted physiological pathways and restore volitional control of movement to paralysed limbs.