Enhanced neurofibrillary degeneration in transgenic mice expressing mutant tau and APP

JNPL3 transgenic mice expressing a mutant tau protein, which develop neurofibrillary tangles and progressive motor disturbance, were crossed with Tg2576 transgenic mice expressing mutant beta-amyloid precursor protein (APP), thus modulating the APP-Abeta (beta-amyloid peptide) environment. The resulting double mutant (tau/APP) progeny and the Tg2576 parental strain developed Abeta deposits at the same age; however, relative to JNPL3 mice, the double mutants exhibited neurofibrillary tangle pathology that was substantially enhanced in the limbic system and olfactory cortex. These results indicate that either APP or Abeta influences the formation of neurofibrillary tangles. The interaction between Abeta and tau pathologies in these mice supports the hypothesis that a similar interaction occurs in Alzheimer's disease.     

Discrete visual defects in pearl mutant mice

The mutant mouse pearl, characterized by its hypopigmentation, has a specific functional defect in a sensory system--the retina. The intact pearl mouse has reduced sensitivity in the dark-adapted condition. Normal sensitivity is restored by isolation and superfusion of the retina with bicarbonate-buffered Ringer solution, suggesting that the retinal expression of the pearl mutation depends on a diffusible substance. The pearl phenotype is described as a possible model for human congenital stationary night blindness.     

中国拒绝疯牛病

随着改革开放的不断深入,中国经济和对外贸易呈现较好的发展势头,特别是在国家新的农业发展战略指引下,农业和畜牧业方面的投资不断增加,使中国与国外间的动物及动物产品的交流日益频繁和活跃.国外优良动物新品种的引进,势必增强我国畜牧业的发展后劲,进而大大提高我国人民生活水平和质量.然而,疯牛病等国外危险性动物疫病不断给我国的动物卫生和人体健康造成新的威胁.面对严峻的形势,中国进出境检验检疫部门严把检验检疫关,有效地御疫于国门之外,防止了疯牛病传入我国.     

Spontaneous neurodegeneration in transgenic mice with mutant prion protein

Transgenic mice were created to assess genetic linkage between Gerstmann-Str?ussler-Scheinker syndrome and a leucine substitution at codon 102 of the human prion protein gene. Spontaneous neurologic disease with spongiform degeneration and gliosis similar to that in mouse scrapie developed at a mean age of 166 days in 35 mice expressing mouse prion protein with the leucine substitution. Thus, many of the clinical and pathological features of Gerstmann-Str?ussler-Scheinker syndrome are reproduced in transgenic mice containing a prion protein with a single amino acid substitution, illustrating that a neurodegenerative process similar to a human disease can be genetically modeled in animals.     

Hypolipidemia in a mutant strain of "acatalasemic" mice

Mutant "acatalasemicm" mice have an unstable catalase in hepatic and renal peroxisomnes that is readily degraded, apparently into peroxidase subunits. The hypothesis that an in situ cataloperoxidase would affect serum lipids was tested in these mutants and serum triglycerides and cholesterol were found to be significantly lower than in the wild strain. This finding is in accordance with reports that a hypolipidemic response to the injection of peroxidase subunits of hepatic catalase occurs in humans and rabbits.     

Spongiform disease. Experts downplay new vCJD fears

The chilling scenario of getting "mad cow disease" from eating products of other animals besides just cows was splashed across the mainstream British press last week based on a report from a leading U.K. lab that prions--abnormal proteins linked to bovine spongiform encephalopathy and its human form, variant Creutzfeldt-Jakob disease--can jump from one species to another more easily than previously believed. Although some experts say the findings raise concern about a threat to human health, others decry the media frenzy and contend that the new research adds little to what is known about the mysterious, fatal diseases.     

疯牛病的研究进展

疯牛病(Bovine Spongiform Encephalopathy,BSE)是一种严重危害畜牧业和人类健康的传染性疾病,该病以侵害中枢神经系统为特征.本文就疯牛病病原、发病机理以及检测方法的研究进展作一综述.     

疯牛病—牛海绵状脑病（BSE）研究进展

疯牛病是一种由朊病毒感染引起的、非炎性致死性的脑退化性疾病，并可传染给人。本文从流行病学、病原学、病理学等方面论述了疯牛病的研究进展情况。详细讨论了朊病毒的生物学特性、致病机理和增殖模式。     

Wild-type nonneuronal cells extend survival of SOD1 mutant motor neurons in ALS mice

The most common inherited [correct] form of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease affecting adult motor neurons, is caused by dominant mutations in the ubiquitously expressed Cu-Zn superoxide dismutase (SOD1). In chimeric mice that are mixtures of normal and SOD1 mutant-expressing cells, toxicity to motor neurons is shown to require damage from mutant SOD1 acting within nonneuronal cells. Normal motor neurons in SOD1 mutant chimeras develop aspects of ALS pathology. Most important, nonneuronal cells that do not express mutant SOD1 delay degeneration and significantly extend survival of mutant-expressing motor neurons.     

Early forebrain wiring: genetic dissection using conditional Celsr3 mutant mice

Development of axonal tracts requires interactions between growth cones and the environment. Tracts such as the anterior commissure and internal capsule are defective in mice with null mutation of Celsr3. We generated a conditional Celsr3 allele, allowing regional inactivation. Inactivation in telencephalon, ventral forebrain, or cortex demonstrated essential roles for Celsr3 in neurons that project axons to the anterior commissure and subcerebral targets, as well as in cells that guide axons through the internal capsule. When Celsr3 was inactivated in cortex, subcerebral projections failed to grow, yet corticothalamic axons developed normally, indicating that besides guidepost cells, additional Celsr3-independent cues can assist their progression. These observations provide in vivo evidence that Celsr3-mediated interactions between axons and guidepost cells govern axonal tract formation in mammals.     

Long lives for homozygous trembler mutant mice despite virtual absence of peripheral nerve myelin

Nervous system functions are dependent on point-to-point communication of signals along neuronal axons, and axonal insulation by myelin is thought to speed such conduction. Loss of previously formed myelin or lack of myelin formation can have serious, even fatal, consequences. Mice homozygous for the trembler mutation make virtually no peripheral nervous system myelin, yet have long and functional lives. This result calls into question the view that peripheral nervous system myelin plays a vital role, at least in this species.