Interstitial deletion of chromosome 15: two cases

Summary Two cases of interstitial deletion of chromosome 15 with similar clinical features are presented. In one case, assay of hexosaminidase A enabled us to confirm that the structural gene is located between 15q22 and 15q25 and that it is included in the deletion.     

Effects of traces of rare earth elements on the protozoanBlepherisma and on mice

The growth of the protozoanBlepherisma is stimulated by Lanthanum (La) at concentrations as low as 0.32 ppm. In mice Yttrium (Y) and Ytterbium (Yb) are absorbed, accumulated, and metabolized. Both rare earth elements (RE) exhibit a high affinity for teeth and bones, accumulation occurs and metabolism is slow. In the livers of RE-exposed mice, concentrations are variable. The liver is apparently capable of absorbing and discharging RE in a manner depending on metabolic activity. The main route of discharge for ingested REs is the alimentary canal. Exposure of pregnant mice to RE leads to rapid placental transfer of RE; 14.1% of the total amount of RE administered was detected in newborn mice. Young, developing organisms appear to be especially susceptible to RE accumulation.     

RNA recombination of murine coronaviruses: recombination between fusion-positive mouse hepatitis virus A59 and fusion-negative mouse hepatitis virus 2.

It has previously been shown that the murine coronavirus mouse hepatitis virus (MHV) undergoes RNA recombination at a relatively high frequency in both tissue culture and infected animals. Thus far, all of the recombination sites had been localized at the 5' half of the RNA genome. We have now performed a cross between MHV-2, a fusion-negative murine coronavirus, and a temperature-sensitive mutant of the A59 strain of MHV, which is fusion positive at the permissive temperature. By selecting fusion-positive viruses at the nonpermissive temperature, we isolated several recombinants containing multiple crossovers in a single genome. Some of the recombinants became fusion negative during the plaque purification. The fusion ability of the recombinants parallels the presence or absence of the A59 genomic sequences encoding peplomers. Several of the recombinants have crossovers within 3' end genes which encode viral structural proteins, N and E1. These recombination sites were not specifically selected with the selection markers used. This finding, together with results of previous recombination studies, indicates that RNA recombination can occur almost anywhere from the 5' end to the 3' end along the entire genome. The data also show that the replacement of A59 genetic sequences at the 5' end of gene C, which encodes the peplomer protein, with the fusion-negative MHV-2 sequences do not affect the fusion ability of the recombinant viruses. Thus, the crucial determinant for the fusion-inducing capability appears to reside in the more carboxyl portion of the peplomer protein.     

Human glutathione S-transferases. The Ha multigene family encodes products of different but overlapping substrate specificities

The human glutathione S-transferase cDNAs encoding subunits 1 and 2 contain intrinsic ribosome-binding sites in their 5'-untranslated regions for direct expression in Escherichia coli. We show that functional human GSH S-transferases 1-1 and 2-2 are synthesized from lambda gt11 cDNA clones lambda GTH1 and lambda GTH2 in phage lysates of E. coli Y1090, in lysogens of E. coli Y1089, and from the plasmid expression constructs in pKK223-3. The E. coli-expressed human GHS S-transferases 1-1 and 2-2 do not have blocked N termini in contrast to those directly purified from human livers. These two isozymes, with 11 amino acid substitutions between them, are similar in their Km values for GSH and 1-chloro-2,4-dinitrobenzene and Kcat values for this conjugation reaction. The human GSH S-transferase 2-2, however, is a more active GSH peroxidase than transferase 1-1 toward cumene hydroperoxide and t-butyl hydroperoxide. Our results indicate that different members of a GSH S-transferase gene family with limited amino acid substitutions have different with limited amino acid substitutions have different but overlapping substrate specificities. We propose that accumulation of single amino acid replacements may be an important mechanism for generating diversity in GSH S-transferases with various xenobiotic substrates. In situ chromosomal hybridization results show that the GSH transferase Ha genes are located in the region of 6p12.     

广西黄皮属六种叶片的比较解剖观察

<正> 芸香科黄皮属(Clausena)植物全球约25种,分布于东半球热带、亚热带地区;我国记载有9种,产长江以南各省区,以两广、云南种类较多;广西现知6种,民间大多作药用,黄皮和小叶黄皮在我国南部广泛栽培,果实供生食或加工,黄皮的优良品种为岭南佳果之一。目前正在挖掘其潜在的药用价值及进行化学成分和挥发油的研究。中国人民解放军181医院药理室,用大鼠进行动物实验,证明黄皮叶有降血脂作用。在研究黄皮属的分类时,某些种的形态特征很接近,叶的形状、大小变化大,在无花果的情况下更难区分,笔者试图从叶的解剖构造探讨种间的差异,为植物分类和生药鉴定提供依据,供临床用药及有关方面参考。     

Analysis of proliferative activity in colorectal mucosa by immunohistochemical detection of proliferating cell nuclear antigen (PCNA). Methodological aspects and application to routine diagnostic material.

Immunohistochemical detection of proliferating cell nuclear antigen (PCNA) has been suggested as a new approach for determining proliferative activity in paraffin-embedded tissue. In a prospective study PCNA immunostaining was performed in 284 colorectal biopsies using monoclonal antibodies 19F4 (Ogata et al. 1987) and PC10 (Waseem and Lane 1990) and compared with the Ki67 method. From each site three biopsies were taken and a variety of fixation regimens for frozen and paraffin-embedded samples tested. For frozen biopsies methanol fixation at -20 degrees C proved best. In paraffin sections PCNA could be detected after methacarn fixation as well as after controled fixation at 4 degrees C in 4% paraformaldehyde for 1 h and in most biopsies routinely fixed with 10% formalin. However, the latter fixation regimens revealed additional PCNA-positive cells in the normal superficial colonic mucosal epithelium. Although the percentage of cells positive for PCNA was generally lower than for Ki67, the rates correlated in a highly significant fashion, both in frozen methanol-fixed biopsies, and in paraformaldehyde-fixed paraffin-embedded samples. PCNA immunohistochemistry revealed a similar proliferative activity in different parts of the large bowel. A higher proliferative activity was found in inflamed mucosa, adenomas, carcinomas and even in normal mucosa from patients with colorectal neoplasms. In routinely fixed biopsies, the monoclonal antibody PC10 was superior to 19F4 because of considerably less background staining. However, in the routine material only a rough estimate of the proliferative activity was possible by PCNA immunohistochemistry using these antibodies, because unpredictable numbers of non-S-phase cells were also stained.(ABSTRACT TRUNCATED AT 250 WORDS)     

柴达木盆地荒漠土壤蓝藻群落的初步研究

本文分析了柴达木盆地东部和中部具有代表性地区的丘陵、戈壁和沙丘的蓝藻种类组成、生物量及主要的土壤化学成分;采用了模糊聚类、系统聚类及多元线性回归等方法分析藻类的群落及其与环境因子的关系。共鉴定出21种蓝藻,其中6种为国内首次报道。研究表明:土壤含磷量、总盐量及与粘性和湿度有关的土壤结构是决定柴达木盆地蓝藻群落组成的重要因素。     

The 32-kilodalton envelope protein of vaccinia virus synthesized in Escherichia coli binds with specificity to cell surfaces.

The nature of interaction between vaccinia virus and the surface of host cells as the first step in virus infection is undefined. A 32-kDa virus envelope protein has been identified as a cell surface binding protein (J.-S. Maa, J. F. Rodriguez, and M. Esteban, J. Biol. Chem. 265:1569-1577, 1990). To carry out studies on the structure-function relationship of this protein, the 32-kDa protein was obtained from Escherichia coli cells harboring the expression plasmid pT7Ek32. The recombinant polypeptide was found to have structural properties similar to those of the native virus envelope protein. Binding studies of 125I-labeled 32-kDa protein to cultured cells of various origins revealed that the E. coli-produced 32-kDa protein exhibited selectivity, specificity, and saturability. Scatchard analysis indicated about 4.5 x 10(4) sites per cell with a high affinity (Kd = 1.8 x 10(-9) M), suggesting interaction of the 32-kDa protein with a specific receptor. The availability of large quantities of the 32-kDa virus protein in bacteria will permit further structural and functional studies of this virus envelope protein and facilitate identification of the specific cell surface receptor.