Direct carrier testing of haemophilia B by SSCP

Summary. Haemophilia B is due to multiple molecular defects in the factor IX gene. Most of them are single base substitutions, and can now be identified by direct sequencing of the coding sequence of the factor IX gene, preceded or not by a screening strategy. In some instances the mutation alters an enzyme recognition site and this allows rapid and accurate carrier testing and prenatal diagnosis in the affected pedigree. This was not the case for the previously described nt 31119 (G– > A) mutation that we found in an extended haemophilia B pedigree, during the search for mutations in the factor IX gene in patients from Southern France. We first detected this mutation by single stranded conformation polymorphism (SSCP) and then identified it by DNA sequencing. Carriership could be easily determined in the females of the pedigree by analysis of the SSCP patterns. Our results indicate that the SSCP analysis of amplified genomic DNA fragments can be successfully used as a diagnosis approach for direct carrier testing and prenatal diagnosis.     

Trisomy 3 in marginal zone B-cell lymphoma: a study based on cytogenetic analysis and fluorescence in situ hybridization

Trisomy 3 represents the most frequent and consistent chromosomal abnormality characterizing the recently defined entity marginal zone B-cell lymphoma (MZBCL). By cytogenetic analysis and/or fluorescence in situ hybridization (FISH) on interphase nuclei we found an increased copy number of chromosome 3 in 22/36 (61%) successfully analysed cases, including 8/12 cases with extranodal MZBCL, 8/13 cases with nodal MZBCL, and 6/11 patients with splenic MZBCL. Sensitivity of interphase cytogenetics was somewhat higher than that of conventional cytogenetic investigation. Structural chromosomal changes involving at least one chromosome 3 were seen in 11/20 cases with an increased copy number of chromosome 3: +del(3)(p13) was demonstrated in three cases, and was the sole chromosomal abnormality in one of them; +i(3)(q10) was seen in two other patients; and rearrangements involving various breakpoints on the long arm of chromosome 3 were found in the remaining cases. FISH on metaphase spreads confirmed these structural abnormalities and additionally showed two unexpected translocations involving chromosome 3. We conclude that: (1) trisomy 3 occurs in a high proportion of extranodal, nodal and splenic MZBCL; (2) FISH on interphase nuclei is an additional and sensitive tool in detecting an increased copy number of chromosome 3 in MZBCL; (3) additional structural abnormalities involving the long arm of chromosome 3 are frequent but non-recurrent and are perhaps secondary changes; and (4) abnormalities such as +del(3)(p13) and +i(3)(q10) suggest that genes located on the long arm of chromosome 3 are of particular importance in the pathogenesis of MZBCL.     

Characterization of variable immunodominant antigens of Cowdria ruminantium by ELISA and immunoblots

Cross-immunization experiments have revealed a significant antigenic diversity of the isolate of Cowdria ruminantium which needs to be characterized for the development of vaccines. We identified polymorphic immunodominant antigens by ELISA and immunoblot. Using serum from a goat immune to the Gardel stock of Cowdria (isolated in Guadeloupe) adsorbed on antigen of the Senegal stock of this pathogen, distinct serogroups were revealed by ELISA among six isolates from different geographical origins. Furthermore, a goat serum directed against the Senegal stock and adsorbed on Gardel antigens was shown to be specific for the Senegal stock, thus confirming the existence of serotypes in Cowdria . The Major Antigenic Protein 1 (MAP1) of Cowdria was shown to have variable antigenic determinants. Also in a group of variable proteins ranging from 23 to 29 kDa, one antigen of 26–27 kDa had a determinant specific for the Gardel isolate. These polymorphic antigens may be relevant components of Cowdria ruminantium for a vaccine as the sera revealing these antigens originated from a goat surviving a lethal challenge. However, the presence of T-cell epitopes and the ability of these antigens to confer protection to ruminants remain to be investigated. The production of a rabbit antiserum against this group of polypeptides will be of great use for their purification and for the screening of expression libraries .     

NUTRITIONAL STATUS IN CHRONICALLY ALCOHOLIC MEN FROM THE MIDDLE SOCIOECONOMIC CLASS AND ITS RELATION TO ETHANOL INTAKE

Two-hundred and fifty chronically alcoholic men (mean age, 41± 11 years) entering an alcoholism treatment programwere studied. Detailed clinical history, nutritional assessmentand measurement of muscle strength by electronic myometer wereperformed in each case. In addition, hepatic ultrasonographyand liver biopsy, echocardiography and radionuclide cardiacscanning, and electrophysiological testing of peripheral nerveswere performed when there was clinical evidence of liver disease,cardiomyopathy or neuropathy, respectively. Alcoholic cirrhosiswas diagnosed in 20 cases, skeletal myopathy in 117, dilatedcardiomyopathy in 20 and peripheral neuropathy in 41 cases.No patients with chronic myopathy or cardiomyopathy showed eitherclinical or laboratory evidence of malnutrition. Patients withcirrhosis showed a significantly lower lean body mass than controls(P = 0.03) and significantly lower nutritional protein levelsthan those alcoholics without cirrhosis. Alcoholics with peripheralneuropathy had significantly lower anthropometric parametersand nutrition protein levels than their counter parts (P <0.001). However, in the multivariate analysis, the only independentfactor for developing these complications of alcoholism wasthe total lifetime dose of ethanol (P < 0.001). We concludethat alcohol-related diseases are common in asymptomatic alcoholicmen and these diseases appear to be due to an accumulative toxiceffect of ethanol. Age and nutritional status do not seem toplay a part in the development of such diseases     

Ostium Primum Atrial Septal Defect Associated with Obstructive Hypertrophic Cardiomyopathy

A 48-year-old white male was referred for cardiac catheterization following a bout of near syncope and severe angina. He was diagnosed to have obstructive hypertrophic cardiomyopathy by transthoracic echocardiography (TTE). Right bundle branch block and plethoric chest X ray suggested shunt physiology, which was confirmed on transesophageal echocardiography and angiocardiography to be a primum type of atrial septal defect (primum ASD) with cleft mitral leaflet. He underwent septal myomectomy and patching of the ASD. Surgical pathological specimen revealed enlarged nuclei and myocardial disarray consistent with congenital hypertrophic cardiomyopathy. (ECHOCARDIOGRAPHY, Volume 8, May 1991)     

Dissociation of Autoaggression and Self-Superantigen Reactivity

Self-superantigens have been described as products of endogenous retroviruses of the mouse ('minor lymphocyte stimulating loci') that are capable of interacting without prior processing with conserved domains of TCR Vβ chains, causing the activation and deletion of most T cells expressing products of determined Vβ gene families [1–4], The fact that superanti-gens activate a far higher percentage of T cells (1–20%) than conventional, peptidic antigens (< 0.1 %) provides the methodological advantage that the degree of clonal deletion may be measured by the analysis of the TCR repertoire using appropriate anti-Vβ antibodies. Although much information on the spatio-temporal organization of repertoire-purging has been gathered by virtue of self-superantigens, serious doubts exist as to the possibility that such structures serve as pathogenetically relevant autoantigens. Thus, certain inbred mice spontaneously develop autoimmune diseases, although they bear T-cell repertoires that appear to be purged from self-superantigen-reactive Vβ products. In addition, therapeutic interventions targeted to Vβ gene products that are not specific for self-superantigens are successful in preventing disease development. The lack of correlation between superantigen-related Vβ deletions and autoimmune disease development is substantiated in further models of murine autoimmunity. Based on these observations, we formulate the hypothesis that self-superantigen-reactive T cells are not involved in the development of autoimmune diseases.