Linkage of Niemann-Pick disease type D to the same region of human chromosome 18 as Niemann-Pick disease type C.

Niemann-Pick type II disease is a severe disorder characterized by accumulation of tissue cholesterol and sphingomyelin and by progressive degeneration of the nervous system. This disease has two clinically similar subtypes, type C (NPC) and type D (NPD). NPC is clinically variable and has been identified in many ethnic groups. NPD, on the other hand, has been reported only in descendants of an Acadian couple who lived in Nova Scotia in the early 18th century and has a more homogeneous expression resembling that of less severely affected NPC patients. Despite biochemical differences, it has not been established whether NPC and NPD are allelic variants of the same disease. We report here that NPD is tightly linked (recombination fraction .00; maximum LOD score 4.50) to a microsatellite marker, D18S480, from the centromeric region of chromosome 18q. Carstea et al. have reported that the NPC gene maps to this same site; therefore we suggest that NPC and NPD likely result from mutations in the same gene.     

HLA-B*57 Micropolymorphism shapes HLA allele-specific epitope immunogenicity, selection pressure, and HIV immune control

The genetic polymorphism that has the greatest impact on immune control of human immunodeficiency virus (HIV) infection is expression of HLA-B*57. Understanding of the mechanism for this strong effect remains incomplete. HLA-B*57 alleles and the closely related HLA-B*5801 are often grouped together because of their similar peptide-binding motifs and HIV disease outcome associations. However, we show here that the apparently small differences between HLA-B*57 alleles, termed HLA-B*57 micropolymorphisms, have a significant impact on immune control of HIV. In a study cohort of >2,000 HIV C-clade-infected subjects from southern Africa, HLA-B*5703 is associated with a lower viral-load set point than HLA-B*5702 and HLA-B*5801 (medians, 5,980, 15,190, and 19,000 HIV copies/ml plasma; P = 0.24 and P = 0.0005). In order to better understand these observed differences in HLA-B*57/5801-mediated immune control of HIV, we undertook, in a study of >1,000 C-clade-infected subjects, a comprehensive analysis of the epitopes presented by these 3 alleles and of the selection pressure imposed on HIV by each response. In contrast to previous studies, we show that each of these three HLA alleles is characterized both by unique CD8(+) T-cell specificities and by clear-cut differences in selection pressure imposed on the virus by those responses. These studies comprehensively define for the first time the CD8(+) T-cell responses and immune selection pressures for which these protective alleles are responsible. These findings are consistent with HLA class I alleles mediating effective immune control of HIV through the number of p24 Gag-specific CD8(+) T-cell responses generated that can drive significant selection pressure on the virus.     

Synthesis and structure–activity relationship of a novel series of heterocyclic sulfonamide γ-secretase inhibitors

γ-Secretase inhibitors have been shown to reduce the production of β-amyloid, a component of the plaques that are found in brains of patients with Alzheimer’s disease. A novel series of heterocyclic sulfonamide γ-secretase inhibitors that reduce β-amyloid levels in cells is reported. Several examples of compounds within this series demonstrate a higher propensity to inhibit the processing of amyloid precursor protein compared to Notch, an alternative γ-secretase substrate.     

(S)-N-(5-Chlorothiophene-2-sulfonyl)-β,β-diethylalaninol a Notch-1-sparing γ-secretase inhibitor

Accumulation of beta-amyloid (Aβ), produced by the proteolytic cleavage of amyloid precursor protein (APP) by β- and γ-secretase, is widely believed to be associated with Alzheimer’s disease (AD). Research around the high-throughput screening hit (S)-4-chlorophenylsulfonyl isoleucinol led to the identification of the Notch-1-sparing (9.5-fold) γ-secretase inhibitor (S)-N-(5-chlorothiophene-2-sulfonyl)-β,β-diethylalaninol 7.b.2 (Aβ _40/42 EC₅₀ = 28 nM), which is efficacious in reduction of Aβ production in vivo.     

Bovine viral diarrhea virus (BVDV) associated with single in vivo-derived and in vitro-produced preimplantation bovine embryos following artificial exposure

The objective was to determine the average amount of bovine viral diarrhea virus (BVDV) associated with single in vivo-derived and in vitro-produced bovine embryos following recommended processing procedures for embryos. In vivo-derived and in vitro-produced bovine embryos at 7 d post-fertilization were exposed (for 2 h) to 2 × 10^5-7 cell culture infective dose (CCID₅₀)/mL of SD-1 (a noncytopathic, Type 1a strain of BVDV), and then washed according to International Embryo Transfer Society (IETS) guidelines prior to testing. Of the 87 in vivo-derived embryos tested, 27% were positive for virus by quantitative polymerase chain reaction (qPCR). The range in amount of virus associated with 99% of the contaminated embryos was ≤6.62 ± 1.57 copies/5 μL; 90% of the contaminated embryos had ≤4.64 ± 1.57 viral copies/5 μL of embryo-associated virus, using tolerance intervals (P < 0.05). The SEM was 0.33 and the mean of averages was 1.12/5 μL. Of the 87 in vitro-produced embryos, 42% were positive for virus. The range in amount of virus associated with 99% of the contaminated embryos was ≤3.44 ± 0.89 copies/5 μL; 90% of the contaminated embryos had ≤2.40 ± 0.89 viral copies/5 μL of embryo-associated virus using tolerance intervals (P < 0.05; S.E.M. was 0.14 and the mean of averages was 0.55/5 μL). Therefore, although many embryos were positive for virus, there were limited numbers of copies, thereby posing doubt regarding their potential for contamination following embryo transfer.