Toll-like receptor 4 deficiency: Smaller infarcts,but nogain in function

Backgound  

It has been reported that Toll-like receptor 4 (TLR4) deficiency reduces infarct size after myocardial ischemia/reperfusion (MI/R). However, measurement of MI/R injury was limited and did not include cardiac function. In a chronic closed-chest model we assessed whether cardiac function is preserved in TLR4-deficient mice (C3H/HeJ) following MI/R, and whether myocardial and systemic cytokine expression differed compared to wild type (WT).     

Antigenic study of the differentiation of the human kidney using monoclonal antibodies

The production of monoclonal antibodies against human embryonic renal cells allowed to display on the adult human kidney some antigens typical of certain structures or tissues: the proximal convoluted tubule for EG 9-11 and EG 19-6 monoclonal antibodies, the glomerular basement membrane for EG 14-1, the urothelium for EE 24-6, the connective tissue for EK 8-1 and EK 17-1 and probably the capsular and tubular basement membranes for EK 8-1. Simultaneously, we could follow the spatial and temporal repartition of the antigens during the renal development. One of them (EI 16-1) seemed to disappear in the adult and might correspond to a foetal type-antigen.     

Molecular diagnosis of Duchenne and Becker muscular dystrophies. Current data

Carrier diagnosis and prenatal diagnosis of Duchenne's muscular dystrophy (DMD) and Becker's muscular dystrophy (BMD) has become possible using some twenty RFLPs detected by more than a dozen Xp21 probes that are either intragenic or flanking the disease locus. Results from familial studies on 88 DMD and BM families stress important considerations concerning a priori and final risks, individuals necessary for the identification of the phase, and the different strategies that can be applied, regardless of whether the study concerns an on-going pregnancy or a carrier-status determination, and whether the patient is at high or low risk. Finally, multiple sources of difficulties in interpreting the results depend on a) the occurrence of new mutations that must be traced; b) the existence of meiotic recombination; c) the necessity, in some instances, of relying upon the sole identification of the paternal X. These considerations emphasize the characteristics and the important limitations of this type of methodology.     

Defective,deleted or converted CYP21B gene and negative association with a rare restriction fragment length polymorphism allele of the factor B gene in congenital adrenal hyperplasia

Summary Defects in the enzyme, steroid 21-hydroxylase, result in congenital adrenal hyperplasia (CAH), a common autosomal recessive disorder of cortisol biosynthesis. The gene encoding this protein (CYP21B) and a closely linked pseudogene (CYP21A) have been mapped in the HLA complex on chromosome 6p, adjacent to the complement genes C4B and C4A, about 80 kb from the factor B gene. Molecular analyses of patients with CAH have shown that the cause of the defect may be either a deletion, a point mutation or a conversion of the active gene. Linkage of the disease to HLA has previously been studied by several groups. We have analyzed DNAs from patients with classical and non-classical CAH and from their family members, by probing with CYP21, C4 and BF cDNAs. In 70% of the CAH haplotypes studied, the defective CYP21B gene was indistinguishable from its structurally intact corresponding gene in Southern blot analysis, and presumably bore point mutations. In the remaining chromosomes, evidence for gene conversions, deletions and various deleterious mutations of the CYP21B gene is given. Moreover, our linkage studies show that a polymorphic TaqI cleavage site in the factor B gene, recently described by us, may be a new and useful genetic marker, because we found this TaqI restriction site only in unaffected haplotypes carrying functional CYP21B genes and, therefore, in negative association with the defective CYP21B gene.     

Structural characterization of the human B lymphocyte-restricted differentiation antigen CD22. Comparison with CD21 (complement receptor type 2/Epstein-Barr virus receptor)

CD22 and CD21 are glycoproteins primarily expressed on normal and neoplastic human B cells. The surface expression of these two molecules parallel each other during normal B cell differentiation, and the reported relative mobilities for CD22 and CD21 are 130/140 kDa and 140 kDa, respectively. Herein we present a detailed analysis of the biosynthesis and structure of CD22 and also compare it directly to CD21. Electrophoresis under reducing and nonreducing conditions suggested that CD22 and CD21 may have similarities in intra-chain disulfide bond formation. Biosynthesis and processing of CD22 and CD21 were very similar with respect to kinetics and post-translational modification, and both could be phosphorylated. However, endoglycosidase digestion (using N-glycanase and endoglycosidase H) and peptide mapping (using V8 protease and N-chlorosuccinimide) strongly suggested that CD22 and CD21 are distinct gene products.     

Clastogen-induced chromosomal breakage as a marker for first trimester prenatal diagnosis of Fanconi anemia

Summary Using cultured trophoblast cells obtained by chorionic villus biopsy, we diagnosed Fanconi anemia (FA) in two pregnancies and excluded it in eight pregnancies at risk for the syndrome. Baseline chromosomal breakage and breakage induced by diepoxybutane (DEB) were analyzed. Increased breakage was used as a marker for the syndrome. Our results were unambiguous and provide a reliable method for prenatal detection of FA in the first trimester of pregnancy.     

Lambda Ig constant region genes are translocated to chromosome 8 in Burkitt''s lymphoma with t(8;22)

By in situ hybridization of normal human chromosomes with a cloned genomic probe specific for the constant region of the lambda immunoglobulin genes, band 22q11 was preferentially labelled. In two cell lines with t(8;22) derived from Burkitt's lymphoma a strong signal was noted on the 8q+ chromosome derivative, indicating that the constant region of the lambda Ig gene cluster was translocated from chromosome 22 to chromosome 8. In addition, the signal observed on the 22q- derivative chromosome was stronger than the background in one of the two cell lines tested, but not in the other. The implications are that the break point in chromosome 22 in some cases lies within the Ig gene itself or between clusters of such genes, and that different cases have different break points.     

Alpha-melanocyte-stimulating hormone immunoreactivity in human melanoma metastases extracts

Seven human melanoma metastases were extracted in order to check the possible presence of any alpha-melanocyte stimulating hormone (MSH) immunoreactivity. The aim of that study was to provide some explanation for, mainly, two observations that we have already made and reported: 1) increased plasma alpha-MSH levels in melanoma of tumour-bearing patients as compared with tumour-free patients; 2) the presence of specific alpha-MSH receptors on human melanoma cells in culture. We could measure large amounts of immunoreactive alpha-MSH in all tumours ranging from 0.31 to 4.27 pmoles per g of wet tissue. Further identification of the extracted material by high-performance liquid chromatography revealed compounds of higher molecular weight and more hydrophobic than synthetic alpha-MSH. In addition, purified extracts could also displace 125I-labelled alpha-MSH from its cellular binding sites in an alpha-MSH specific radio-receptor binding assay. Our findings would suggest a possible presence of some hormone precursor(s) inside the melanoma tumours.     

Prenatal diagnosis of Niemann-Pick type C disease: current strategy from an experience of 37 pregnancies at risk.

Thirty-seven pregnancies at risk for Niemann-Pick type C disease were monitored by study of cultured amniotic fluid cells (8 cases) or chorionic villus cells (29 cases) in 23 couples over the period 1984-91. An early protocol combined determination of sphingomyelinase activity with electron microscopy. The current strategy, based on the demonstration of specific abnormalities in intracellular processing of exogenous cholesterol, combines the study of the early phase (first 6 h) of LDL-induced cholesteryl ester formation and the histochemical evaluation (filipin staining after 24 h of LDL uptake) of the LDL-induced accumulation of unesterified cholesterol. Thirteen fetuses were predicted to be affected. Confirmation of the diagnosis was made by study of cholesterol processing in fetal skin fibroblast cultures and/or by demonstration of a characteristic lipid storage in fetal liver, already present at 14 w gestation. Definition of the biochemical phenotype (classical, variant, or intermediate) of the index case, with regard to cholesterol-processing abnormalities, is an absolute prerequisite to adequate genetic counseling in a given family. Prenatal diagnosis has now proved a safe procedure in the predominant (approximately 85%) group of families with the classical phenotype.