Interferon-alpha alters spectrin organization in normal and leukemic human B lymphocytes

Interferon-alpha (IFN-alpha) regulates the growth, differentiation, and recirculation of normal and malignant B lymphocytes. In this report we examine the effects of IFN-alpha on the distribution of the cytoskeletal protein spectrin in peripheral blood B lymphocytes from normal donors and patients diagnosed with chronic lymphocytic leukemia (CLL) and hairy cell leukemia (HCL). Exposure of normal and leukemic B cells to IFN-alpha in vitro was shown by immunofluorescence microscopy to cause a dose-dependent increase in the percentage of cells containing discrete focal accumulations of spectrin, ie, a single large aggregate or cap-like structure near the plasma membrane. Although the magnitude of this effect was variable among individual patient samples, in some experiments IFN-alpha induced a fourfold increase in the percentage of leukemic B cells exhibiting focal accumulations of spectrin. Spectrin reorganization induced by IFN-alpha was abrogated by the protein synthesis inhibitor cycloheximide. In addition, IFN-alpha increased the total cellular content of spectrin in B-CLL cells by approximately twofold to fourfold. Finally, a role for protein kinase C in mediating the effects of IFN-alpha on spectrin's organization is implicated by studies in which calphostin C inhibited the IFN-induced focal accumulation of spectrin. Taken together, these studies suggest that the immunomodulatory activities of IFN-alpha in normal and malignant B cells involve a change in the organization of the spectrin- based cytoskeleton.     

Identification of mutations in the connexin 26 gene that cause autosomal recessive nonsyndromic hearing loss

Mutations in the Cx26 gene have been shown to cause autosomal recessive nonsyndromic hearing loss (ARNSHL) at the DFNB1 locus on chromosome 13q12. Using direct sequencing, we screened the Cx26 coding region of affected and nonaffected members from seven ARNSHL families either linked to the DFNB1 locus or in which the ARNSHL phenotype cosegregated with markers from chromosome 13q12. Cx26 mutations were found in six of the seven families and included two previously described mutations (W24X and W77X) and two novel Cx26 mutations: a single base pair deletion of nucleotide 35 resulting in a frameshift and a C-to-T substitution at nucleotide 370 resulting in a premature stop codon (Q124X). We have developed and optimized allele-specific PCR primers for each of the four mutations to rapidly determine carrier and noncarrier status within families. We also have developed a single stranded conformational polymorphism (SSCP) assay which covers the entire Cx26 coding region. This assay can be used to screen individuals with nonsyndromic hearing loss for mutations in the CX26 gene. Hum Mutat 11:387–394, 1998. © 1998 Wiley-Liss, Inc.     

天然抗氧化剂抗血管生成作用的研究进展

血管生成（Angiogenesis）是指从已有的血管上长出新的毛细血管的过程．在这一过程中,活性氧作为信号分子起着非常重要的作用．因此从天然抗氧化剂中寻找新的血管生成抑制剂已成为近年来研究的热点,我们综述了近年来抗氧化剂的抗血管生成作用、机制以及应用前景的国内外最新研究进展．     

74例血友病B患者FⅨ基因突变研究

目的 研究导致中国人血友病B的凝血因子Ⅸ（FⅨ）基因突变类型的分布,并比较与美国白种人群有何异同。方法 从患者外周血白细胞抽提基因组DNA,分9段扩增Ⅸ基因外显子序列,用基因扩增转录测序技术直接测序法检出突变。结果 74例患者中有69例查到了FⅨ基因58种突变。分析比较这69例患者FⅨ基因突变类型的分布特征与美国白种人无显著性。中国不同地区之间差异也无显著性。结论 中国人血友病B的FⅨ基因突变类型非常分散,呈高度异质性。与美国白种人之间相比差异无显著性。     

Improvement of wound tissue repair by chitosan films containing (–)‐borneol,a bicyclic monoterpene alcohol,in rats

The aim of this study was to investigate the wound‐healing activity of (–)‐borneol (BOR) incorporated in chitosan film on healing protocol in rodents. To assess the BOR wound‐healing potential, male Wistar rats were subjected to a full‐thickness excisional wound. The animals were divided into three groups: dressed with chitosan‐based film (QUIN); dressed with chitosan‐based film containing 0·5% BOR (QUIBO05); or dressed with chitosan‐based film containing 1% BOR (QUIBO1). Dressing the wound areas and histological analysis were performed on the 3rd, 7th, 14th, and 21st days. The myeloperoxidase (MPO) activity was assessed on the third and seventh days after surgical procedures. Wounds dressed with chitosan‐based film containing BOR reduced significantly the MPO activity (P < 0·001), showed significantly larger wound retraction rates (7 days, P < 0·05), improved the granulation reaction, and also provided better collagenisation density and arrangement during wound healing. It is suggested that BOR modulates the wound‐healing process and is a promising compound to be used in wound care. This product may be quite useful in improving wound healing and could be a new biotechnological product with healing properties and clinical application. Further ongoing studies will enable us to understand the precise mechanisms whereby BOR improves the wound‐healing process.     

Bi-directional dideoxy fingerprinting (Bi-ddF): a rapid method for quantitative detection of mutations in genomic regions of 300-600 bp

There is a great need for rapid screening methods that detect essentially all mutations. Dideoxy fingerprinting (ddF) is a highly sensitive screening method that is performed by electrophoresing one lane of a Sanger dideoxy termination reaction through a nondenaturing gel. Mutations may produce an extra segment or eliminate a segment from the termination products (informative dideoxy component). In addition, mutations can be detected by the altered mobility of one or more termination segments (informative SSCP component). To screen larger segments with virtually 100% sensitivity, bi-directional ddF (Bi-ddF) was developed. Bi-ddF is a 'second generation ddF' in which the dideoxy termination reaction is performed simultaneously with two opposing primers. Bi-ddF has two important advantages over ddF: (i) the dideoxy component can detect 10 of the 12 types of possible single-base substitutions; and (ii) the SSCP component is enhanced because alterations of mobility can be detected in either the downstream or upstream direction. As a result, Bi-ddF can screen larger regions of genomic DNA with virtually 100% sensitivity. Bi-ddF detected 100% of 28 single-base substitutions in a 494 bp segment containing exons B and C of the human factor IX gene and 100% of 42 single-base substitutions and one microdeletion present in a 577 bp region containing exon H. In a blinded analysis in which 39 wildtype samples were randomly mixed with 51 mutant samples, all mutations were detected with no false positives. Bi-ddF requires essentially the same effort as ddF, yet twofold more DNA sequence can be screened reliably per unit effort.