Synergic in-vitro activity of imipenem and sulbactam against Acinetobacter baumannii

The interaction between sulbactam and imipenem was evaluated with four clinical isolates of Acinetobacter baumannii, including two isolates resistant to imipenem, one of which produced IMP-1 metallo-beta-lactamase. Two isolates (one of which was imipenem-resistant) were sulbactam-resistant by undefined mechanisms. MICs were determined by standard broth microdilution methods. Time-kill assays with imipenem and sulbactam, alone or in combination at 0.5 x MIC and 1 x MIC, showed a synergic effect in all four isolates of A. baumannii after incubation for 0, 4, 8 and > 24 h at 35 degrees C.     

Stereoselective determination of cetirizine and studies on pharmacokinetics in rat plasma

Enantiomers may confer benefits over racemates in therapeutic uses and we developed a chiral separation method of cetirizine enantiomers, a second generation H1 histamine receptor antagonist, in rat plasma. alpha1-Acidglycoprotein based chiral stationary phase(AGP-CSP), monitored with UV at 230 nm was used to separate the enantiomers. Observed enantioselectivity (alpha) was 2.0. The AGP-CSP was also used at a preparative scale to isolate the enantiomers with an optical purity of greater than ee 99%. In addition, an analysis was carried out for the cetirizine enantiomers in rat plasma to study the differences of enantiomers in pharmacokinetics. Both (+)- and (-)-cetirizine were separated using a reversed-phase column of AGP, and were detected at the range of 2.5-200 microg ml(-1) in plasma. Although there was no recognizable differences in pharmacokinetics between the enantiomers in rat, the method appears to be useful for their pharmacokinetic studies.     

Stratification based on language-related endophenotypes in autism: attempt to replicate reported linkage.

The identification of autism susceptibility genes has been hampered by phenotypic heterogeneity of autism, among other factors. However, the use of endophenotypes has shown preliminary success in reducing heterogeneity and identifying potential autism-related susceptibility regions. To further explore the utility of using language-related endophenotypes, we performed linkage analysis on multiplex autism families stratified according to delayed expressive speech and also assessed the extent to which parental phenotype information would aid in identifying regions of linkage. A whole genome scan using a multipoint non-parametric linkage approach was performed in 133 families, stratifying the sample by phrase speech delay and word delay (WD). None of the regions reached suggested genome-wide or replication significance thresholds. However, several loci on chromosomes 1, 2, 4, 6, 7, 8, 9, 10, 12, 15, and 19 yielded nominally higher linkage signals in the delayed groups. The results did not support reported linkage findings for loci on chromosomes 7 or 13 that were a result of stratification based on the language delay endophenotype. In addition, inclusion of information on parental history of language delay did not appreciably affect the linkage results. The nominal increase in NPL scores across several regions using language delay endophenotypes for stratification suggests that this strategy may be useful in attenuating heterogeneity. However, the inconsistencies in regions identified across studies highlight the importance of increasing sample sizes to provide adequate power to test replications in independent samples.     

Growth hormone deficiency,aortic dilation,and neurocognitive issues in Feingold syndrome 2

We report three patients with Feingold 2 syndrome with the novel features of growth hormone deficiency associated with adenohypophyseal compression, aortic dilation, phalangeal joint contractures, memory, and sleep problems in addition to the typical features of microcephaly, brachymesophalangy, toe syndactyly, short stature, and cardiac anomalies. Microdeletions of chromosome 13q that include the MIR17HG gene were found in all three. One of the patients was treated successfully with growth hormone. In addition to expanding the phenotype of Feingold 2 syndrome, we suggest management of patients with Feingold 2 syndrome include echocardiography at the time of diagnosis in all patients and consideration of evaluation for growth hormone deficiency in patients with short stature.     

Alterations in extracellular matrix components in transplant glomerulopathy

The distribution pattern of extracellular matrix (ECM) components in transplant glomerulopathy was studied in relation to light microscopic features, actin expression of mesangial cells, and intraglomerular inflammatory cells. Nine cases of mild (group I) and nine cases of severe (group II) transplant glomerulopathy were stained with antisera against fibronectin (FN), tenascin (TN), collagen types III and IV, smooth muscle actin, CD45RO, CD68, and Ki-67 antigen. The composition of ECM was similar in the two groups. The expanded mesangium was diffusely stained by type-IV collagen, FN and TN, and focally and weakly stained by type-III collagen and smooth muscle actin. Type-IV collagen was linearly stained along the capillary walls, imparting a double-contour feature, whereas FN and TN showed granular staining along the capillary walls. CD68 positive cells were increased in severe transplant glomerulopathy, but this increase was not related to ECM deposition. These findings suggest that increased glomerular deposition of normal and abnormal ECM components participate in the evolution of transplant glomerulopathy. Received: 5 October 1999 / Accepted: 17 January 2000     

Reduced thirst in old, thermally dehydrated rats

Water intake and blood parameters of young (7-month) and old (23-month) male Brown Norway rats were assessed following a period of thermal dehydration. Rats of both ages were randomly assigned to one of three groups: (1) Unheated-blood sample, (2) Heated-blood sample, and (3) Heated-water intake. The colonic temperature of heated rats was raised at the rate of 0.05 degrees C/min for 1 h using an infrared heat lamp. Water intake was then measured over the following 2 h. The heating protocol resulted in a similar level of dehydration in both young and old rats; however, plasma osmolality and sodium concentration increased to a significant extent only in the young rats. Old rats drank significantly less water at all time points during the 2 h following the heat stress. While neither group replaced the water lost as a result of the thermal dehydration, the young rats did rehydrate to a greater extent. These results suggest that the diminished level of rehydration in aged rats, following a thermal dehydration, is due to an attenuated rise in plasma osmolality.     

Five haplotypes account for fifty-five percent of ATM mutations in Brazilian patients with ataxia telangiectasia: seven new mutations

We have studied the molecular genetics of 27 Brazilian families with ataxia telangiectasia (AT). Five founder effect haplotypes accounted for 55.5% of the families. AT is an autosomal recessive disorder of childhood onset characterized by progressive cerebellar ataxia, ocular apraxia, telangiectasia, immunodeficiency, radiation sensitivity, chromosomal instability, and predisposition to cancer. The ATM gene spans more than 150 kb on chromosome region 11q23.1 and encodes a product of 3056 amino acids. The ATM protein is a member of the phosphatidylinositol 3-kinase (PI-3K) family of proteins and is involved in cell cycle control and DNA repair pathways. DNA was isolated from lymphoblastoid cell lines and haplotyped using four STR markers (D11S1818, NS22, D11S2179, D11S1819) within and flanking the ATM gene; all allele sizes were standardized in advance. In addition to the STR haplotypes, SNP haplotypes were determined using 10 critical polymorphisms. The entire gene was screened sequentially by protein truncation testing (PTT), single strand conformation polymorphism (SSCP), and then denaturing high performance liquid chromatography (dHPLC) to identify the disease-causing mutations. Of the expected 54 mutations, 50 were identified. All mutations but one, led to a truncated or null form of the ATM protein (nonsense, splice site, or frameshift). Five families (18.5%) carried a deletion of 3450nt (from IVS28 to Ex31), making this one of the two most common Brazilian mutations. Mutations were located throughout the entire gene, with no clustering or hotspots. Standardized STR haplotype analysis greatly enhanced the efficiency of mutation screening.     

First serologic evidence of human spotted fever group rickettsiosis in Korea

To investigate the prevalence of spotted fever group rickettsioses in Korea, a serosurvey of Japanese spotted fever rickettsiosis in patients with acute febrile illness was conducted with an indirect immunofluorescence assay. Overall, 19.88% of the patients were found to have polyvalent antibody against Rickettsia japonica. This study is the first documentation of spotted fever group rickettsiosis in Korea.     

A novel Plasmodium falciparum erythrocyte binding protein-2 (EBP2/BAEBL) involved in erythrocyte receptor binding

The 175-kDa erythrocyte binding protein (EBA-175) of Plasmodium falciparum and Duffy antigen binding proteins of P. vivax and P. knowlesi are members of a protein family. The features of this protein family include a cysteine-rich motif present in the erythrocyte receptor-binding domain. We identify here a novel 140-kDa P. falciparum erythrocyte binding protein (EBP2/BAEBL) containing the signature cysteine-rich motif by comparative analysis of gene sequence information. Polyclonal antibodies generated by immunization with an EBP2/BAEBL DNA vaccine immunoprecipitated a 140-kDa protein from P. falciparum schizont-infected erythrocyte lysates. Similar to EBA-175, the binding of EBP2/BAEBL to human erythrocytes was dependent on sialic acids because neuraminidase treatment of those erythrocytes rendered them incapable of binding, but differed from EBA-175 in that trypsin treatment decreased EBP2/BAEBL binding by only twofold compared to a 10-fold reduction in EBA-175 binding. Antibodies raised against the putative erythrocyte-binding domain of EBP2/BAEBL effectively blocked the binding of native EBP2/BAEBL to erythrocytes. These functional antibodies localize EBP2/BAEBL to the invasive apical end of the merozoite. We identify EBP2/BAEBL as a paralogue of EBA-175 and as a novel P. falciparum vaccine candidate.     

应用复合诱导突变分离PCR法检测mtDNA的单核苷酸多态性

目的应用复合诱导突变分离PCR(multiplexed mutagenically separated PCR,MS-PCR)技术、银染分型,建立线粒体DNA(mitochondrial DNA,mtDNA)编码区单核苷酸多态(single nucleotide polymorphism,SNP)分型系统,探讨其应用价值。并调查了成都汉族群体mtDNA编码区4个SNP基因座等位基因频率和单倍型分布情况。方法根据SNP基因座(C12705T、A8701G、G8584A、C10400T)设计两条片段相差4个碱基的等位基因特异性引物和一条公共引物,4个SNP基因座复合扩增,PCR产物经聚丙烯酰胺凝胶电泳、银染显带后确定样本的基因型。结果不同SNP基因座为长度不同的单一谱带,其分型结果与直接测序一致。在成都汉族160名无关个体中,4个SNP基因座C12705T、A8701G、G8584A、C10400T等位基因频率分别为0.3813/0.6187、0.4813/0·5187、0.8250/0.1750、0.4938/0.5062;共检出6种单倍型,单倍型的基因多样性为0.7137。结论建立的MMS-PCR银染分型系统是一种简单、快速、准确、有效的SNP分型方法,对建立mtDNA编码区SNP数据库,研究群体遗传学、进化学和进行法医学个人识别和亲子鉴定有重要意义。