Modulation of apolipoprotein B antigenic determinants in human low density lipoprotein subclasses

To investigate the effect of low density lipoprotein (LDL) heterogeneity on the conformation of LDL apolipoprotein B (apo-B), the immunoreactivities of 6 monoclonal antibodies against LDL apo-B were measured in 3 LDL subfractions isolated by equilibrium density gradient ultracentrifugation. To ensure a broad range of LDL particles, the LDL subfractions were prepared from normal subjects and patients with hyperapobetalipoproteinemia. With 3 of the antibodies, 1D1, 5E11, and 3A10, LDL fractions 1 (the most buoyant), 2 (the intermediate), and 3 (the densest) were equally immunoreactive and competed similarly with reference whole LDL. In contrast, with 3 other antibodies, 2D8, 3F5, and 4G3, fraction 1 was significantly more reactive than fraction 3; that is for each in turn, 290, 250, and 150% more of the densest LDL protein was required to achieve the same displacement as with fraction 1. Further, the immunoreactivities of the 3 LDL fractions with antibodies 2D8, 3F5, and 4G3 were negatively correlated with their LDL cholesterol to LDL protein ratio with r values of 0.727, 0.898, and 0.870, respectively, suggesting that as LDL particle size decreases, the conformation of the LDL apo-B changes progressively. It is of interest that the antigenic determinants recognized by 3F5 and 4G3 are close to the LDL receptor recognition site on LDL apo-B. Therefore, it is possible that the reduced immunoreactivity of these determinants in dense LDL may be the in vitro correlate of the reduced fractional catabolics rate of dense LDL compared to buoyant LDL previously observed in vivo.     

Analysis of the sheep MHC using HLA class I,II, and C4 cDNA probes

Four cDNA probes for the human major histocompatibility complex (MHC) were used to investigate the sheep MHC, in conjunction with serological typing for ovine lymphocyte antigen (OLA). Lymphocytes from a family (two parents and five offspring) of Romanov sheep were subjected to genomic DNA digestion by the restriction endonuclease Eco RI, followed by gel electrophoresis. A single Southern blot representing all seven individuals was then consecutively hybridized with the class I, alpha-DC, beta-DR, and C4 probes, which were originally designed to identify HLA class I, class II (DC and DR), and C4 products, respectively. Using each of the three class I/class II probes, several bands showing DNA polymorphism were detected. The segregation of these bands in the five offspring exactly paralleled the OLA haplotype segregation established by serological typing. A further eight individuals carrying haplotypes which were phenotypically identical to those in the above-mentioned family showed bands in the corresponding positions when tested with the same three probes. Using the C4 probe, no polymorphism was detected in these fifteen individuals.Abbreviations used in this paper MHC major histocompatibility complex - OLA ovine lymphocyte antigen - kbp kilobase pair(s) - MLR mixed lymphocyte reaction - RFLP restriction fragment length polymorphism     

Polymorphisms within the HLA-DR3 haplotypes

HLA-DR molecules were isolated from eight different HLA-DR3 homozygous B-cell lines by immunoprecipitation with monoclonal antibodies, and they were subsequently analyzed by two-dimensional gel electrophoresis. We found that HLA-DR3 homozygous B-cell lines of consanguineous origin express two types of HLA-DR molecules. One type of HLA-DR molecule was present in all the cell lines tested, whereas the second DR molecule appears to be polymorphic. DNA isolated from the different HLA-DR3 homozygous cell lines was studied by Southern blot analysis to determine whether any DR restriction fragment length polymorphism could be observed. Polymorphisms detected at both the product and genomic level have been compared to each other, and their relations to the serological (HLA-DR) and cellular (HLA-D and LB-Q1) typing data will be discussed.No reprints available     

Distribution of chlorpromazine and imipramine in adipose and other tissues of rats

Adipose tissue kinetics of chlorpromazine and imipramine, two drugs which are more lipophilic than thiopental, were studied in the rat. After single i.v. doses, the time-course of drug distribution was followed in adipose and various other tissues, until their concentrations in adipose tissues declined. Under these conditions the two drugs behaved almost identically. Among the tissues analyzed, the lowest concentrations were found in adipose tissue, with the exception of plasma. At its maximum concentration after about 30 minutes, total adipose tissue contained only 3 % of the dose of administered drugs. Adipose/plasma and adipose/lung concentration ratios were 2–5 and 0.05, respectively.After maximum tolerated oral doses of imipramine for 3 weeks, similar steady state concentration ratios (plasma:adipose:brain:lung 1:3:12:96) were observed. In adipose tissue the imipramine/desmethylimipramine ratio was about 1, and the desmethylimipramine steady state levels did not increase with time. Literature data indicate that many basic lipophilic drugs are not stored in adipose tissue. This is now clearly shown for chlorpromazine and imipramine, even under extreme, subchronic conditions in the case of imipramine.     

Transfer RNA genes ofZea mays chloroplast DNA

A minimum of 37 genes corresponding to tRNAs for 17 different amino acids have been localized on the restriction endonuclease cleavage site map of theZea mays chloroplast DNA molecule. Of these, 14 genes corresponding to tRNAs for 11 amino acids are located in the larger of the two single-copy regions which separate the two inverted copies of the repeat region. One tRNA gene is in the smaller single-copy region. Each copy of the large repeated sequence contains, in addition to the ribosomal RNA genes, 11 tRNA genes corresponding to tRNAs for 8 amino acids. The genes for tRNA₂ ^Ile and tRNA^Ala map in the ribosomal spacer sequence separating the 16S and 23S ribosomal RNA genes. The three isoaccepting species for the tRNAs^Leu and the three for tRNAs^Ser, as well as the two isoaccepting species for tRNA^Asn, tRNA^Gly, tRNAs^Ile, tRNAs^Met, tRNAs^Thr, are shown to be encoded at different loci. Two independent methods have been used for the localization of tRNA genes on the physical map of the maize chloroplast DNA molecule: (a) cloned chloroplast DNA fragments were hybridized with radioactively-labelled total 4S RNAs, the hybridized RNAs were then eluted, and identified by two-dimensional polyacrylamide gel electrophoresis, and (b) individual tRNAs were³²P-labelledin vitro and hybridized to DNA fragments generated by digestion of maize chloroplast DNA with various restriction endonucleases.     

La forme scléronodulaire de la maladie de Hodgkin: expérience du CHU de Sherbrooke

Scleronodular type of Hodgkin''s disease: experience at the Centre hospitalier universitaire de SherbrookeThe nodular sclerosis type of Hodgkin''s disease appears to be a distinct clinical entity. However, the incidence, the initial localization of the tumour and the survival of the patients are variable. The present study was carried out on a group of 17 patients, all French Canadians living in the province of Quebec, from a total of 31 with Hodgkin''s disease, an incidence of 55%. There were more males (10) than females (7). The mean age of the group was 37 years, but that of the females was lower than that of the males. The mediastinum was involved at the onset in 47% of the patients. The initial staging (according to the classification of Rye) in 76% of the patients was I or II.Four patients showed disease below the diaphragm. The lungs were infiltrated three times, the spleen six times, and the liver five times. The duration of survival of the 17 patients was twice that of the patients with the three other types of the disease.     

Differents aspects du fer dans l'organisme : II. Différentes formes de l'hémosidérine

On voit des molécules de ferritine apparaitre dans le cytoplasme des cellules réticulaires au cours de la digestion des érythrocytes, autour des stromas phagocytés. Cette ferritine s'accumule en amas dans lesquels entrent d'autres substances, en particulier des lipides, provenant aussi des stromas globulaires et qui apparaissent sous forme myélinique. Souvent la ferritine se dispose d'une manière cristalline. Parfois la ferritine et l'apoferritine alternent dans ces cristaux. Parfois l'hémosidérine contient des cristaux qui semblent bien être de l'apoferritine pure. L'injection de sels de fer donne lieu à l'apparition de ferritine dans les cellules réticulaires. Dans les conditions de nos expériences, la plus grande partie du fer injecté était sous forme de ferritine dans un délai de 3 jours. Un aspect intermédiaire entre celui du fer injecté et celui de la ferritine a été trouvé. Dans le cas des injections de saccharate de fer ce sont de fines aiguilles; dans le cas des injections de lactate de fer, il s'agit de masses fibreuses.     

Autoradiographies de Coupes d'os compact après marquage aux isotopes in vitro

Résumé Etude qualitative et quantitative du marquage in vitro de coupes d'os compact. Détermination du rôle joué par les processus de diffusion, d'adsorption et d'échange dans ces phénomènes.

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Zusammenfassung Qualitative und quantitative Studie der in vitro-Markierung von Schliffen aus Knochen-Compacta. Bestimmung der Rolle der Diffusions-, Adsorptions- und Austauschprozesse für diese Vorgänge.

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La partie expérimentale de ce travail a pu être réalisée grâce à des subsides fournis par l'European Office of the Air Research and Development Command [contrat n^o AF 61 (514) 1175], par l'Institut Interuniversitaire Belge des Sciences Nucléaires, et par la Commission pour la Science Atomique du Fonds National Suisse de la Recherche Scientifique.