Temperature rising elution fractionation of a random ethene/styrene copolymer

A random ethene/styrene copolymer containing 13.8 mol-% styrene was prepared with the Ziegler-Natta catalyst system Me₂Si(Me₄Cp)(N-t-butyl)TiCl₂/methylaluminoxane and characterized by means of preparative temperature rising elution fractionation (TREF) combined with size exclusion chromatography, NMR, differential scanning calorimetry and wide-angle X-ray scattering analyses of the copolymer fractions. Efforts are made to describe the distribution of the styrene content of the copolymers using the Stockmayer-Tacx distribution function. Both, comonomer distribution and molar mass distribution strongly support the presence of a single type of catalytically active center.     

Assessment of HER‐2/neu overexpression and/or gene amplification in breast carcinomas: should in situ hybridization be the method of choice?

AIMS: Since the release of Herceptin, pathology laboratories have been requested to test breast carcinomas for HER-2/neu overexpression and/or gene amplification. Standardized IHC and FISH are mandatory in order to get reliable results, but there are problems even with standardized procedures. We decided to evaluate the two methods to determine which, or possibly if both, should be the primary investigation method(s). METHODS AND RESULTS: The material consisted of 215 primary invasive breast carcinomas with complete clinical follow-up of 15 years. HER-2/neu protein expression was determined for all specimens, whereas FISH for assessing HER-2/neu gene signal number was done in 165 cases. IHC was double-checked with two or three different antibodies in 35 tumours, including all cases with discrepancies between IHC and FISH. Among these, there were discrepancies in a third. IHC overexpression of HER-2/neu was found in 13% and gene amplification in 18%. Discordance between IHC and FISH was found in 11 cases (8%). Five tumours were IHC+/FISH- and six were IHC-/FISH+. IHC and FISH positive cases as well as FISH only positive tumours had the same prognosis respecting survival. Tumours with >2 but 4 gene signals per nucleus. In contrast, cases with IHC overexpression without gene amplification had a prognosis similar to that of IHC-/FISH- tumours. CONCLUSIONS: From our data, it seems to be more important to assess HER-2/neu gene amplification than IHC overexpression. Failure to detect FISH-amplified (IHC-negative) cases would have an adverse effect on the survival of these patients. On the other hand, IHC overexpression tumours without gene amplification appear to belong to a better prognostic group, and failure to detect them would probably not have a negative effect on the survival of these women. Even though FISH is a more complex and expensive procedure, it should be considered the method of choice for primary assessment of HER-2/neu status in breast cancer patients.     

Autosomal dominant inheritance of left ventricular outflow tract obstruction

Most nonsyndromic congenital heart malformations (CHMs) in humans are multifactorial in origin, although an increasing number of monogenic cases have been reported recently. We describe here four new families with presumed autosomal dominant inheritance of left ventricular outflow tract obstruction (LVOTO), consisting of hypoplastic left heart (HLHS) or left ventricle (HLV), aortic valve stenosis (AS) and bicuspid aortic valve (BAV), hypoplastic aortic arch (HAA), and coarctation of the aorta (CoA). LVOTO in these families shows a wide clinical spectrum with some family members having severe anomalies such as hypoplastic left heart, and others only minor anomalies such as mild aortic valve stenosis. This supports the suggestion that all anomalies of the LVOTO spectrum are developmentally related and can be caused by a single gene defect.     

Natural transmission of a partial AZFb deletion of the Y chromosome over three generations: case report

The natural transmission of microdeletions of the Y chromosome is occasionally reported in the literature. Here we describe the natural transmission of a partial AZFb deletion over three generations. PCR amplification of several sequence tagged site markers in the three AZF regions of the Y chromosome was carried out in a patient with oligoasthenoteratozoospermia, his father and his naturally conceived son. The deletion was confirmed by Southern blotting. The propositum, his father and his son showed a probably identical, partial deletion of the distal part of the AZFb region, involving sY130 and sY143. The deletion was confirmed by Southern blotting using the sY130 probe. Partial AZFb microdeletions can be associated with moderate oligozoospermia allowing natural conception and therefore natural transmission of this genetic anomaly. Further studies are needed to define the pathogenetic significance of microdeletions involving sY130 and sY143.     

Interpersonal callousness, hyperactivity/impulsivity, inattention, and conduct problems as precursors to delinquency persistence in boys: a comparison of three grade-based cohorts.

Boys who exhibit interpersonal callousness (IC), hyperactivity/impulsivity (HI), inattention (IN), and conduct problems (CP) may be at risk for exhibiting persistent delinquent behavior. However, few studies have established the distinctiveness of these constructs or examined their relative contributions to the prediction of delinquent behavior across different developmental periods. This study explores these issues using boys from the youngest (1st grade, N = 849), middle (4th grade, N = 868), and oldest (7th grade, N = 856) cohorts of the Pittsburgh Youth Study. Confirmatory factor analysis indicates that the 4 constructs are related, yet independent, from childhood to adolescence. After controlling for the overlap among the constructs, CP significantly predicted delinquency persistence in the youngest cohort, whereas CP and IN predicted delinquency persistence in the middle cohort. IC uniquely predicted delinquency persistence for the oldest cohort. The results suggest that the saliency of specific predictors of delinquent behavior may change from childhood to adolescence.     

DGGE-based whole-gene mutation scanning of the dystrophin gene in Duchenne and Becker muscular dystrophy patients

Duchenne and Becker muscular dystrophy (DMD and BMD) are caused by mutations in the dystrophin gene. Large rearrangements in the gene are found in about two-thirds of DMD patients, with approximately 60% carrying deletions and 5-10% carrying duplications. Most of the remaining 30-35% of patients are expected to have small nucleotide substitutions, insertions, or deletions. To detect these subtle changes within the coding and splice site determining sequences of the dystrophin gene, we established a semiautomated denaturing gradient gel electrophoresis (DGGE) mutation scanning system. The DGGE scan covers the dystrophin gene with 95 amplicons, PCRed either individually or in a multiplex setup. PCR and pooling were performed semiautomatically, using a pipetting robot and 384-well plates, enabling concurrent amplification of DNA of four patients in one run. Amplification of individual fragments was performed using one PCR program. The products were pooled just before gel loading; DGGE requires only a single gel condition. Validation was performed using DNA samples harboring 39 known DMD variants, all of which could be readily detected. DGGE mutation scanning was applied to analyze 135 DMD/BMD patients and potential DMD carriers without large deletions or duplications. In DNA from 25 out of 44 DMD patients (57%) and from 5 out of 39 BMD patients (13%), we identified clear pathogenic changes. All mutations were different, with the exception of one DMD mutation, which occurred twice. In DNA from 10 out of 44 potential DMD carriers, including four obligate carriers, we detected causative changes, including one pathogenic change in every obligate carrier. In addition to these pathogenic changes, we detected 15 unique unclassified variants, i.e., changes for which a pathogenic nature is uncertain.     

LTD4 augments TNF releasein vivo andin vitro

In vivo data suggest a role of LTD₄ in mediating endotoxin (LPS)-inducible liver injury in galactosamine-sensitized mice. Leukotriene D₄ (LTD₄) was shown to synergize in this model with subtoxic amounts of LPS in inducing hepatitis. Mice challenged i.v. with a subtoxic dose of LPS [50 ng/kg] showed significant TNF serum levels 90 min later which were sixfold increased by coadministration of 50 μg/kg LTD₄. When rat Kupffer cells were challenged with LPS, TNF-α measured in the supernatant was significantly increased by LTD₄ [100 pg–100 ng/ml]. Addition of LTD₄ alone did not result in any detectable TNF formation.Since Kupffer cells are known producers of small amounts of LTD₄, it seems feasible that LTD₄ represents an autocrine stimulus of nonparenchymal liver cells. In fact, different LTD₄ synthesis inhibitors and receptor antagonists attenuated LPS-inducible TNF release of rat Kupffer cells supporting the conclusion that LTD₄ acts as an endogenous autocrine enhancer of liver macrophage TNF release.