Vesicular pityriasis rosea: response to erythromycin treatment

Pityriasis rosea (PR) is a relatively common disease although its aetiology has not yet been identified. It occurs worldwide and there is no racial susceptibility factor. It usually affects teenagers and young adults between 10 and 35 years of age. Typical PR is much easier to diagnose than the rare atypical forms. We report a rare case of vesicular PR in a black woman who had vesicular lesions limited to her palms and soles in addition to regular typical lesions. We devised an efficient oral erythromycin treatment for this patient.     

Molecular genetics and transgenic model of Gertsmann-Str?ussler-Scheinker disease.

Gerstmann-Str?ussler-Scheinker disease (GSS) is a rare, dominantly inherited neurodegenerative disease that can sometimes be transmitted to experimental animals through intracerebral inoculation of brain homogenates from patients. Substitution of leucine for proline at codon 102 of the prion protein gene has been found in several families with the disease; this mutation is genetically linked to GSS. Mice containing murine prion protein transgenes with this mutation spontaneously develop neurologic symptoms of ataxia, lethargy, and rigidity accompanied by spongiform degeneration throughout the brain. Thus, many of the clinical and pathological features of the GSS have been reproduced in this transgenic mouse paradigm; to our knowledge, this study illustrates, for the first time, that a neurodegenerative process similar to a human disease can be genetically modeled in animals. Whether or not this transgenic mouse model of GSS may facilitate the understanding of common neurodegenerative disorders such as Alzheimer disease remains to be established.     

Immunoblotting of Creutzfeldt-Jakob disease prion proteins: host species-specific epitopes

Creutzfeldt-Jakob disease (CJD) is a rare dementia that is generally found in older people and is caused by unusual infectious pathogens or prions. Using rabbit antisera raised against hamster scrapie prion proteins (HaPrPSc), we identified by immunoblotting human CJD prion proteins (HuPrPCJD) in the brains of 14 patients dying of CJD. Extracts from 6 of the patients were transmitted to mice after prolonged incubation. The rabbit antisera raised against HaPrPSc also reacted with the mouse CJD prion proteins (MoPrPCJD) found in the brains of these experimentally infected mice. When mice were immunized with HuPrPCJD, they produced antibodies that reacted with HuPrPCJD but not with MoPrPCJD. Mice immunized with MoPrPCJD produced antibodies to neither murine nor human prion proteins. Our results provide evidence for host species-specific epitopes on prion proteins. The existence of such epitopes is consistent with the apparent lack of an immune response during prion infections and the finding that prion protein molecules are encoded by host genes.     

环孢菌素A阻断人HL－60抗药性细胞于G_1期而诱导敏感细胞凋亡

进一步研究了抗三尖杉酯碱的ＨＬ－６０细胞（ＨＲ２０）抗细胞凋亡的机制及该抗性和抗药性的关系。结果表明，环孢菌素Ａ（ＣｓＡ）２０，１０μｇ·ｍｌ￣（－１）诱导ＨＬ－６０细胞发生凋亡，而阻断ＨＲ２０细胞于Ｇ＿１期，就不能诱导细胞发生凋亡。低浓度的ＣｓＡ明显增加柔红霉素在ＨＲ２０细胞内的积聚，其逆转抗药性作用与阻断细胞周期运行无关。ＣｓＡ１０μｇ·ｍｌ￣（－１）处理ＨＲ２０细胞，可引起５０ｋＤａ的蛋白质高度磷酸化。结果提示：环孢菌素Ａ阻断抗三尖杉酯碱的ＨＬ－６０细胞于Ｇ＿１期，而诱导敏感的ＨＬ－６０细胞发生凋亡，其阻断作用与抗药性无关     

Replication of distinct scrapie prion isolates is region specific in brains of transgenic mice and hamsters.

Scrapie prions are composed largely, if not entirely, of PrPSc molecules. The prion isolates Sc237 and 139H exhibit markedly different incubation times in Syrian, Armenian, and Chinese hamsters, as well as in transgenic (Tg) 81 mice expressing Syrian hamster PrP (SHaPrP). Repassage of prions from transgenic mice or Chinese hamsters into Syrian hamsters revealed that the original properties of the prion isolates are retained. When Syrian hamsters were first inoculated with 139H prions and subsequently challenged with Sc237 prions, the incubation period was determined by the faster Sc237 isolate. Regional mapping studies demonstrated different kinetics and patterns of PrPSc accumulation for Sc237 and 139H prions in the brains of Syrian hamsters as well as Tg(SHaPrP)7 mice. That distinct prion isolates induce different region-specific accumulations of PrPSc in brain suggests a novel mechanism for propagation of isolates whereby they replicate in particular sets of neurons. The prion isolates could be targeted to specific CNS cells by differing conformations of PrPSc, post-translational modifications of PrPSc such as Asn-linked glycosylation, or an as yet undetected macromolecule complexed with PrPSc in the prion.     

Prion Protein Transgenes and the Neuropathology in Prion Diseases

The concept that prions are novel pathogens which are different from both viroids and viruses has received increasing support from many avenues of investigation over the past decade. Enriching fractions from Syrian hamster (SHa) brain for scrapie prion infectivity led to the discovery of the prion protein (PrP). Prion diseases of animals include scrapie and “mad cow” disease; those of humans present as inherited, sporadic and infectious neurodegenerative disorders, two of which are called Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker disease (GSS). The inherited human prion diseases are genetically linked to mutations in the PrP gene that result in non-conservative amino acid substitutions. Transgenic (Tg) mice expressing PrP carrying a GSS mutation developed neurodegeneration spontaneously and produced prions de novo. In other studies, Tg mice expressing both SHa and mouse (Mo) PrP genes were used to demonstrate that the “species barrier” for scrapie prions resides in the primary structure of PrP. This concept was strengthened by the results of studies in which mice expressing chimeric Mo/human (Hu) PrP transgenes were constructed which differ from MoPrP by nine amino acids between residues 96 and 167. All of the Tg(MHu2M) mice developed neurologic disease ～200 days after inoculation with brain homogenate from three patients who died of CJD. About 10% of Tg(HuPrP) mice expressing HuPrP and non-Tg mice developed neurologic disease >500 days after inoculation with CJD prions. The different susceptibilities of Tg(HuPrP) and Tg(MHu2M) mice to human prions indicate that additional species specific factors such as chaperone proteins are involved in prion replication. Diagnosis, prevention and treatment of human prion diseases should be facilitated by study of Tg(MHu2M) mice. Our findings and those from other studies suggest that mutant and wtPrP interact, perhaps through a chaperone-like protein, during the pathogenesis of the prion diseases.     

Needle biopsy of renal allografts: comparison of two techniques

Two techniques for renal allograft biopsy were retrospectively evaluated to compare relative safety and efficacy. After ultrasound (US) localization of the kidney and biopsy with a hand-held 14-gauge cutting needle, an adequate specimen was obtained in 74 of 77 cases (96%). Major complications occurred in six of these 77 cases (8%). One hundred four biopsies were performed by using a smaller 18-gauge cutting needle with a spring-loaded biopsy "gun" and real-time US guidance. With this newer technique, specimens adequate for diagnosis were obtained in 99 biopsies (95%). There was a single major complication with this technique (1%). The 18-gauge needle with real-time US guidance yields comparably adequate specimens with a lower frequency of complications.