Synthesis and characterization of α-hydroxy, α-thiol and α-chloroformyl oligomers of poly(butylene terephthalate)

α-Hydroxy and α-chloroformyl oligomers of poly(butylene terephthalate) (PBT) were prepared in 1,1,2,2-tetrachloroethane by condensing terephthaloyl chloride and 1,4-butanediol and using benzoyl chloride and 4-hydroxybutyl benzoate as chain limitator. The average molecular weight was determined by ¹H NMR analysis, and thermal properties were assessed by differential scanning calorimetry (DSC). Preparation of α-thiol oligomers of PBT was also investigated by esterification of α-hydroxy oligomers with thioglycolic acid and using p-toluenesulfonic acid as catalyst. The DSC and TGA analyses pointed out that the introduction of a thiol group by esterification has no influence on the thermal properties of the PBT oligomers.     

Analysis on distribution and genomic diversity of high-level antiseptic resistance genes qacA and qacB in human clinical isolates of Staphylococcus aureus

High-level antiseptic resistance of Staphylococcus aureus is mediated by multidrug efflux pumps encoded by qacA and qacB genes. We investigated distribution and genomic diversity of these antiseptic resistance genes in a total of 522 clinical strains of S. aureus isolated recently in a Japanese hospital. The qacA/B gene was detected in 32.6% of methicillin-resistant S. aureus (MRSA) and 7.5% of methicillin-susceptible S. aureus (MSSA), whereas the low-level resistance gene smr, which was examined simultaneously, was detected at lower frequencies in both MRSA (3.3%) and MSSA (5.9%). Epidemiologic typing of S. aureus isolates suggested that higher prevalence of qacA/B in MRSA may be due to spread of a single predominant MRSA strain carrying qacA/B in the hospital. Restriction fragment length polymorphism (RFLP) analysis indicated higher prevalence of the qacB-type gene (59.3%) than the qacA-type gene (40.7%) among the qacA/B genes detected. Nucleotide sequencing analysis revealed the presence of two genetic variants in qacA (V1 and V2) and four variants in qacB (V1-V4) that differ from the qacA prototype in pSK1 by 1-5 nucleotides and 7-9 nucleotides, respectively. Although most strains with qacA-V1, qacA-V2, qacB-V3, and qacB-V4 showed high-level resistance to ethidium bromide (EB)(MIC > 100 microg/ml), all of the S. aureus isolates carrying qacB-V1 and qacB-V2 showed lower MICs of EB and some monovalent cationic antiseptic substances. By analysis of the genomic organization of the qacA/B downstream region, divergent forms of this region rearranged with an insertion of IS256 or IS257 were found primarily for qacB. The downstream region of qacA-V1 was suggested to be an evolutionary origin for other divergent forms. These findings indicated that both qacA and qacB are prevalent in recent clinical isolates, especially in MRSA, and these genes consist of variable genetic variants that may be responsible for different resistance levels against antiseptic substances.     

Genetic linkage analysis identifies new proximal and distal flanking markers for the X-linked agammaglobulinemia gene locus, refining its localization in Xq22

Genetic linkage analysis has been instrumental in mapping thegene for X-linked agammaglobulinemia (XLA) to the proximal longarm of the human X chromosome, to Xq22. Due to the relativerarity of this disease the localization of the gene within Xq22has remained imprecise. We have investigated twenty-nine familiesaffected by XLA and have found no recombinants with the DXS178locus in over 30 informative meioses. DXS178 is now the mostreliable and informative locus for use in pre-natal diagnosisand carrier detection of XLA. In addition, we have identifiednew closely linked proximal and distal flanking markers forXLA, DXS442 and DXS101, respectively. These loci are separatedby 2cM, considerably reducing the extent of DNA within whichthe XLA locus can be contained. This will open up the way formore directed positional cloning efforts for the isolation ofthe XLA gene.     

Refined genetic mapping of autosomal recessive chronic distal spinal muscular atrophy to chromosome 11q13.3 and evidence of linkage disequilibrium in European families

Chronic distal spinal muscular atrophy (Chronic DSMA, MIM (*)607088) is a rare autosomal recessive disorder characterized by a progressive motor weakness and muscular atrophy, predominating in the distal parts of the limbs. A form of Chronic DSMA gene has been previously mapped to chromosome 11q13 in the 10.3 cM interval defined by loci D11S1889 and D11S1321. By linkage analysis in 12 European Chronic DSMA families, we showed that a disease gene maps to chromosome 11q13.3 (Z(max)=6.66 at theta=0.00 at the DSM4 locus) and suggested that this condition is genetically homogeneous. Recombination events allowed us to reduce the genetic interval to a 2.6 cM region, telomeric to the IGHMBP2 gene, excluding this gene as the disease causing gene in Chronic DSMA. Moreover, partial linkage disequilibrium was found between three rare alleles at loci D11S1369, DSM4 and D11S4184 and the mutant chromosome in European patients. Analysis of the markers at these loci strongly suggests that most Chronic DSMA chromosomes are derived from a single ancestor. Refinement of the Chronic DSMA locus will hopefully allow to test candidate genes and lead to identification of the disease-causing mutations.     

Mise au point sur l'analyse par chromatographie par exclusion stérique en milieu aqueux de télomères de l'acide acrylique

In the case of water soluble polymers, the use of size exclusion chromatography (SEC) for the determination of the molecular weight involves numerous difficulties. In order to analyse and determine the molecular weight of acrylic acid telomers we have first tried to obtain a satisfactory and reproducible separation. In this particular case, low-molecular-weight standards are not commercially available. Therefore, we decided to prepare standards based on acrylic acid, either by telomerization with a fluorinated telogen or by polymerization with an initiator bearing a fluorinated group. A calibration curve was obtained from the standards. Telomers of acrylic acid with thioglycolic acid were analysed. This is a general method for determination of DP _n by SEC when there is no standard for the polymers. It can be used in a wide range of DP _n from 1 to 700.     

Aspiration cytology of chromophobe cell carcinoma of the kidney

Fine-needle aspiration biopsy findings in three cases of chromophobe cell carcinoma are described and correlated with histologic and ultrastructural observations. In addition, comparisons are made with three cases each of oncocytoma and granular cell carcinoma. The cells in aspiration smears from chromophobe cell carcinoma closely correlated with histologic pattern of three cell types which were not present in oncocytomas and granular cell carcinomas. These cells had prominent cell borders, and their cytoplasm was either opaque and granular (type I) or variably translucent and reticular (type II and III). Ultrastructurally, the translucent areas within the cytoplasm contained large numbers of microvesicles which were unique to chromophobe cell carcinoma and were not seen in other neoplasms. Fine-needle aspiration may be used to diagnose chromophobe cell carcinoma and distinguish it from other related renal neoplasms. © 1995 Wiley-Liss, Inc.     

Fourteen novel OPA1 mutations in autosomal dominant optic atrophy including two de novo mutations in sporadic optic atrophy

The OPA1 gene, encoding a dynamin-related GTPase that plays a role in mitochondrial biogenesis, is implicated in most cases of autosomal dominant optic atrophy (ADOA). Sixty-nine pathogenic OPA1 mutations have been reported so far. Most of these are truncating mutations located in the GTPase domain coding region (exons 8-16) and at the 3'-end (exons 27-28). We screened 44 patients with typical ADOA using PCR-sequencing. We also tested 20 sporadic cases of bilateral optic atrophy compatible with ADOA. Of the 18 OPA1 mutations found, 14 have never been previously reported. The novel mutations include one nonsense mutation, 3 missense mutations, 6 deletions, one insertion and 3 exon-skipping mutations. Two of these are de novo mutations, which were found in 2 patients with sporadic optic atrophy. The recurrent c.2708_2711delTTAG mutation was found in 2 patients with a severe congenital presentation of the disease. These results suggest that screening for OPA1 gene mutations may be useful for patients with optic atrophy who have no affected relatives, or when the presentation of the disease is atypical as in the case of early onset optic atrophy.     

“Pulmonary tongue” a right ventricle phase abnormality in muga studies in patients with pulmonary hypertention

Pulmonary hypertension (PH) produces strain followed by hypertrophy and later dilatation of the right ventricle (RV) and pulmonary artery. The signs and symptoms are nonspecific. There is a need for a noninvasive sensitive way to diagnose PH. The purpose of this study is to evaluate phase abnormalities in radionuclide MUGA studies of patients with referred diagnosis of PH. In a retrospective analysis of 44 patients who had a radionuclide multigated study (MUGA) and contrast ventriculography (CV), 19 had high mean pulmonary pressure (over 20 mmHg) and a high pulmonary vascular resistance index (over 2.0). In 15 patients, a delayed phase segment in the RV corresponding to the pulmonary infundibulum and pulmonary conus was noted The Pulmonary Tongue sign (PT), 12 had PH (True positive) and 3 did not (false positive) on CV. No PT was seen in the remaining 29 patients, only 7 of them had PH (False negative). The sensitivity, specificity and accuracy of the PT sign in detecting PH was 80%, 72% and 77% respectively. The number of patients was too small to calculate the correlation of the grade of PT with the severity of PH. We conclude that The Pulmonary Tongue sign on a MUGA study is clinically useful in detecting PH.This project is supported by research project MLNO13 and funded by research Council, Kuwait University     

Toxicokinetics and molecular interaction of [14C]-formaldehyde in rats

The excretion, tissue distribution, and binding of [¹⁴C]-formaldehyde were studied at different time intervals in male rats following a single intraperitoneal injection of 72 mg CH₂O (14.7 Ci)/ kg body weight. Within 30 min, 10% of the total dose was recovered in expired air as¹⁴CO₂ and by the end of 72 hr, 41% of the administered dose was eliminated through expired air. The total elimination of¹⁴CH₂O activity in urine and feces in 72 hr was 15%. Erythrocytes retained significant amounts of radioactivity, even at the end of 72 hr. Substantial levels of radioactivity were detected in most tissues one hr after administration, indicating a fast absorption and rapid distribution. Subcellular fractionation of the tissues showed that the highest levels of relative percent binding was in the microsomal fraction, whereas cytosol fractions contained lowest levels of bound radioactivity. DNA, RNA, protein and lipid fractions of liver and spleen tissues showed significantly elevated levels of¹⁴C-incorporation as compared to other tissues. Thein vivo incorporation of¹⁴C-activity showed an increased association of¹⁴CH₂O with RNA in all the tissues. The maximum registration of radioactivity in RNA was at 48 hr after administration. Significantly higher amounts of¹⁴C-activity were registered in DNA of all tissues. The maximum registration of radiolabel in DNA of most tissues was at 12 hr after the¹⁴CH₂O administration. The liver DNA showed maximal levels at 3 hr with a second peak at 48 hr.Substantial amounts of bound radioactivity in nucleic acids of all the tissues were observed even 72 hr after dosing. The relationship between macromolecular association and formaldehyde toxicity has been discussed.