Medical Research Society 52 P gens. More recent studies have shown associations with the DQ subregion. The DP subregion lies centromeric to DQ, and although DP-typing can be performed by primed lymphocyte testing, this technique is difficult and not widely available. The aim of this study was to examine the DP-alpha gene with regard to susceptibility to CD, using recombinant DNA techniques. DNA from 58 CD patients and 80 healthy controls was studied by Southern blotting, using a Bgl I1 digest and a genomic DP-alpha probe (kindly provided by J. Trowsdale, ICRF, London). This detects a polymorphism characterised by allelic fragments sized 3.5 and 2.2 kb. The distribution of genotypes in controls and patients is shown in the table: genotype: controls n=80 CD n=58 3.5/3.5 3.5/2.2 2.2/2.2 3.75% 32.5% 74.1% 63.75% 25.9 % 0 % p(O.0001 Thus CD is strongly associated with possession of the 3.5 kb allele; the relative risk (calculated by the method of Woolf) is 5.0 (95% confidence limits 2.2 - 7.9). We conclude that genes important in determining susceptibility to CD are located centromeric to the HLA-DQ subregion and closer to the HLA-DP subregion. THE APOPROTEIN B GENE I N EXTRACORONARY ATHEXOSCLEROSIS 185 A POLYMORPHISM OF G. O'Connor, J . Stocks, and D.J. Galton. Diabetes and Lipid Bartholomew's Lospital, Laboratory, LONDON EC1 7 B E . St. Athrrosclerosis has a strong familial com?onent and reconbinant DNA techno lo:,^ can be used to identify the genes responsible for this. The apoprotein B gene is a useful candidate, since it's product i s the major of low density prorein component lipoproteins. We studied a group of 4 6 patients with angio~raphically proven si t e s at e 1: t ra c o r ona r y at hero s c 1e K O s i s (carotid and aortofemoral) to determine the frequencies of restriction fragment length polymorphisms. These were identified by hybridization of a cloned human apoprotein E gene to patient DNA which v7as digested with the restriction endonuclease Xba-1. The results were compared with those f r o m a group o f 4 7 healthy controls selected from a health screen in^ clinic. from whole blood and DNA was isolated dizested vith Xba-1. The resultant fragments were s ~ p a r a t e d according to size using agaruse &el electrophoresis, and transferred Southern blotting. to a nylon nembrane b y T h e position of tiLe fraL;ments was revealed by hybridization to a labelled apo-B gene probe and autoradioGraphy. The fragments obtained wPre 8.6 kilobase 5.0 kilobase pairs ( X 2 pairs ( X I allele) and allele) in length. The X 1 allele frequency 0.5 in patients. was 0.415 in cor.tro1.s and The X 2 allele frequencies w e r ~0 . 5 6 5 and 0.5 respectively (chi square = 4 . 4 3 , p < 0.05). The genotype frrquencies did not differ between the groups. 186 SPECIFIC INHIBITION OF MACROPHAGE PHAGOCYTOSIS OF SENESCENT HUMAN NEUTROPHILS BY MONOSACCHARIDES J. SAVILL AND C. HASLETT. Department of Medicine, Royal Postgraduate Medical School, DU Cane Road, London W12 OHS. Macrophage (Md) phagocytosis of neutrophils (PMN) occurs in vivo. At inflammatory sites, specific recognition and "disposal" of intact effete PMN by Md may limit tissue injury by preventing release of phloqistic contents from PMN otherwise dooned to disintegration. In vitro evidence suggests that aging PMN may develop specific surface changes recognizable to Md: human PMN isolated from normal peripheral blood and "aged" in culture for 24 hours are phagocytosed by monocyte derived Md; freshly isolated PMN are not recognized. HLA compatibility and serum are not required (1). We have developed a 30 minutes serum free assay of M+aged PMN interaction, quantified by microscopy and myeloperoxidase staining. At 37OC and pH 7.4. 46.1 +2.3% (mean fSE, n=159) of Md ingested aged PMN. (Only 3.4 +0.3%, n=36, of Md recognize freshly isolated PMN). A specific sugar-lectin recognition system in Md-aged PMN interaction was sought by inclusion of monosaccharides at lOmMolar (ionic strength 0.145) and 5 0 mMolar (ionic strength 0.125) in the assay at pH 7.4; the proportion of Md ingesting aged PMN was expressed as % of control (mean tSE; *indicates pCO.01 by Wilcoxon rank sum). Glucose (10 mM:95.9 f2.1%, n=12 - 50 mM:98.1 +4.6%, n=5), Fucose (lOmM:99.6 +2.6%, n=12 - 50mM:lOO.l ?3.0%, n=8), Mannose (lOmM:99.1 +3.0%, n=10 - 50mM:100.5 ?3.9%, n=6), Galactose (10mM:100.2 +3.1%, n=10 - 50mM:gg.l fl.l%, n=6), N-acetylglucosamine (lOmM:97.5 +1.6%, n=15 - 50mM:100.3 +2.7%, n=8) and N-acetylgalactosamine (10mM:gg.g +2.4%, n=10 - 50mM:100.2 +2.2%, n=8) had no effect on Md phagocytosis of aged PMN. However, the amino-sugars glucosamine (1OmM:39.7 ?1.6%*, n=32 - 50mM:23.5 ?3.1%*, n=10) and galactosamine (lOmM:49.5 f2.3%*, n=15 - 50mM:27.4 ?0.9%, n=5) specifically inhibited Md phagocytosis of aged PMN phaqocytosia of opsonised ox erythrocytes was not affected (>99%) nor was aged PMN viability (>97% by trypan blue exclusion). In summary, glucosamine and galactosamine specifically inhibit Md phaqocytosis of aged PMN, suggesting that a lectin-like cell surface structure may mediate this interaction. (1) Newman et al, J Exp Med 1982: 156 : 430. 187 REDUCED PIdDTEIN SYNTHESIS A3 A CAUSE OF AKOHOLF INDUCED SKELETIU. MUSCLE MYVPAPAI V.R. PREEDY AND T.J. PETERS Division of Clinical Cell Biology, Centre, Harrow, Middlesex MRC Clinical Research Alcoholic patients frequently exhibit skeletal muscle weakness and wasting. Histological investigations have revealed a selective reduction in the diameter of Type 11 fibres. Type I fibres are relatively unaffected. These changes may be the direct result of ethanol toxicity on protein synthesis in skeletal muscle. To test this hypothesis we measured fractional rates of protein synthesis in 1009 male rats (n-7-9) given an i.p. injection of ethanol (75nmol/kg BW). Controls were injected with an isovolumetric amount of 0.15mol/l NaC1. At the e d of 140 min rats were intravenously injected with [ 4 'Hlphenylalanine ( 1 5 O ~ l / l O O gBw) to measure fractional rates of protein synthesis. Results, based on the assumption that the precursor phenylalanine waa derived from the intraoellular pool, shared that the synthesis of myofibrillar proteins in gastrocnemius muscle fell by 26% (p < 0.01). A similar decline was observed in sarcoplasmic ( 2 6 % fall, p < 0.01) and stromal fraction8 (29% fall, p < 0.01). Rates of protein synthesis w e r e also examined in Type I (plantaris) and Type I1 (soleus) fibre-rich muscles. The decline in the Type I muscle (22% fall, p < 0.01) was less than the decline in Type I1 muscles (30% fall, p < 0.001). There was a significant change in the Type I/Type I1 ratio of synthesia rates (11% increase, p < 0 . 0 5 ) . Similar fractional synthesis rates were obtained when the data was calculated from the assumption that the precursor phenylalanine was derived from the extracellular pool. In conclusion, muscle protein synthesis is reduced in direct response to ethanol. The relative sensitivity of protein synthesis in Type I1 fibre-rich muscles may be related to the selective reduction in the diameter of Type I1 fibres of alcoholic patients.
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