Molecular analysis of HLA allelic frequencies and haplotypes in Jordanians and comparison with other related populations.

Twenty alleles for the locus human leukocyte antigen (HLA-A) and 46 for the HLA-B locus were detected in Jordanians. This indicates the existence of high polymorphism in this area. The most frequent HLA class I alleles found were A*0201 (0.1344), B*0713 (0.1724), and C*0502 (0.1793). Twenty-six different alleles in the Jordanian population were identified for the DRB1 locus being the DRB1*0704 (0.2552), DRB1*0401 (0.1965), and DRB1*1501 (0.0896) the most frequent. Common DQA1 alleles were DQA1*0201 (0.2690), DQA1*0301 (0.2414), and DQA1*0501 (0.1724). Three-loci haplotype heterogeneity was common: 38 HLA class II haplotypes were identified, of which the most frequently observed was DRB1*0401-DQA1*0301-DQB1*0302 (0.1793). In addition, as expected, 220 different five-loci haplotypes with several unusual allelic combinations were observed, although many of them are pan-European haplotypes. The most frequent five-loci haplotype was the A30-B7-DRB1*03-DQA1*0501-DQB1*0201 (0.0138). It seems that the specific Jordanian haplotypes are the following: the A31-B7-DRB1*04/07-DQA1*0301/0201-DQB1*0302/0202 haplotypes (0.0103) and the A1-B7-DRB1*07-DQA1*0201-DQB1*0202, A2-B7-DRB1*04-DQA1*0301-DQB1*0302, A11-B7-DRB1*07-DQA1*0201-DQB1*0201 haplotypes but at lower frequencies (0.007). A tree analysis of HLA class I and class II alleles were made for several Caucasian populations and individual genetic distances calculated. The haplotype frequencies, genetic distances, and dendrograms do not reveal great differences as compared with those in other Mediterranean countries and Western Europeans populations. Our results suggest that both HLA class I and class II polymorphism (but especially the former) of the Jordanian population demonstrates considerable heterogeneity, which reflects ancient and recent admixture with neighboring populations, and important human migratory trends throughout the history.

Comparative study of the levels of antioxidants of students at Amman and Dead Sea level.

The effect of hyperoxia on the level of the antioxidants: glutathione (GSH) in the whole blood and the enzymes, catalase, superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6-PGD), was studied in the erythrocytes of male high school students living at Dead Sea level (390 m below Sea level and 794.7 mm Hg), and compared with those of students living at Amman level (766 m above sea level and 697.5 mm Hg). The levels of the antioxidant enzymes were found to be lower at Dead Sea level than in Amman, except for the catalase level, which was similar in both groups. The ratio of GSH/Hb was significantly higher in the blood of students at Dead Sea level than in Amman. The combined activities of the antioxidants protected the RBC's but permitted increased level of GSH/Hb in the blood to protect peripheral cells from damage by oxidants.

Pyruvate kinase (PK) deficiency in Jordan.

BACKGROUND AND METHODS: The clinical and biochemical aspects of two cases of PK deficiency associated with chronic hemolytic anemia in two unrelated patients are reported. The residual erythrocyte PK enzymes in both patients were characterized by the recommended methods of the International Committee for Standardization in Hematology (ICSH). RESULTS AND CONCLUSIONS: Patient (W.Q.) had 60% residual PK activity and may be considered homozygous on the basis of consanguinity in the family. This patient suffered from moderate hemolytic anemia that improved after splenectomy. The enzymatic properties were: low activity, moderate thermal stability, reduced affinity for phosphoenol-pyruvate (PEP), and normal electrophoretic mobility. Patient (E.O.) had 42% residual PK activity and may be considered compound heterozygous since his parents are not related. He suffered from moderate hemolytic anemia. The enzymatic properties were: low activity, moderate thermal stability, reduced affinity for PEP and minimal retardation in electrophoretic migration. Theses two cases of PK deficiency are the first to be discovered in Jordan and probably the first in any Arab country.

GM1 ganglioside enhances cholinergic parameters in the brain of senescent rats.

GM1 ganglioside and nerve growth factor both promote the recovery of injured central cholinergic neurons in young animals. Brain cholinergic activity declines with aging and nerve growth factor has been shown to correct cholinergic deficits in senescent animals. We have administered GM1, to young (three months old) or senescent (22-24 months old) rats and evaluated acetylcholine and choline content, choline acetyltransferase and acetylcholinesterase activity as well as choline uptake in striatum, hippocampus and frontal cortex. For some studies, nerve growth factor was administered alone or together with GM1. Our results indicate that cholinergic neurochemical parameters are decreased in some brain areas of senescent animals and that both GM1 and nerve growth factor can enhance their recovery.

Inhibition of acetylcholinesterase by caffeine, anabasine, methyl pyrrolidine and their derivatives.

The inhibition of acetylcholinesterase (AChE) by caffeine, anabasine, methylpyrrolidine and several derivatives was examined. Most of the compounds had moderate inhibitory activity with I50 values in the range of 87-480 microM. The inhibition of AChE by these compounds has not been previously reported. A structural feature common to these compounds is the N-methyl determinant of the pyrrolidine ring which may be important in binding to the AChE.

Phosphoglycerate kinase San Francisco: a new variant associated with hemolytic anemia but not with neuromuscular manifestations.

Phosphoglycerate kinase deficiency is a rare, x-linked glycolytic defect that, when severe, can be associated with hemolytic anemia, rhabdomyolysis, or neurological disorders. We report here a new phosphoglycerate kinase variant discovered in a boy with severe hemolytic anemia but no evidence of neuromuscular disease or developmental delay. The biochemical properties of the variant enzyme (greatly increased kmATP and km3-phosphoglycerate; normal pH optimum, electrophoretic mobility, and substrate specificity; resistance to heat inactivation) establish its uniqueness. Separation of light and dense red cells by centrifugation showed no greater loss of phosphoglycerate kinase activity in dense ("old") variant cells than in normal cells. We postulate that the striking stability of the variant enzyme allows cells capable of protein synthesis to accumulate sufficient enzyme to limit neuromuscular sequelae.

Two new glucose-6 phosphate dehydrogenase (G6PD) variants associated with hemolytic anemia: G6PD Amman-1 and G6PD Amman-2.

Two glucose-6-phosphate dehydrogenase (G6PD) variants were investigated. G6PD Amman-1 was partially purified from the red cells of a patient suffering from recurrent jaundice and spontaneous episodic attacks of severe hemolysis in the absence of oxidant drugs, infection, or fava beans. The enzymatic characteristics of G6PD Amman-1 were markedly reduced activity, fast eletrophoretic mobility, slightly increased km for NADP, normal km for G-6-P, normal heat stability, normal utilization of substrate analogues 2-deoxy G-6-P and deamino-NADP, and a monophasic pH curve with a peak at 8.5 to 9.3. The second variant, G6PD Amman-2, was partially purified from the red cells of a patient suffering from recurrent jaundice with episodic mild hemolysis caused by infection or unknown factors. G6PD Amman-2 characteristics were severely reduced activity, slow electrophoretic mobility, normal km for NADP, decreased km for G-6-P, decreased heat stability, increased utilization of substrate analogues, and a monophasic pH curve with a narrow peak at pH 9.5. The red cell level of reduced glutathione was markedly decreased with twofold increase in the activity of glutathione reductase in the patient with G6PD Amman-2.

Relationship of biochemical drug effects to their antitumor activity--II. Diacridines and membrane-related reactions.

A method is presented that determines the degree of attachment of cancer cells to normal cells. This method may be useful in determining the extent to which treatment of normal cells (or of a tumor-bearing host) with a particular chemotherapeutic agent may affect the degree of attachment of cancer cells to the normal cells. The effects of several diacridines upon this process are described. In addition, we have determined the ability of individual diacridines to alter the permeability of P-388 cells; this effect has been related to their antitumor properties. In general, the most effective antitumor diacridines are those that cause minimal disruption of cell permeability. Conversely, diacridines that disrupt cell permeability tend to have poor antitumor properties. It is considered that the toxicity of these compounds may be a necessary consequence of the assays used for testing anticancer agents, and may not necessarily be related to their antitumor activity.

Changes in allosteric properties of phosphofructokinase bound to erythrocyte membranes.

Human and rabbit erythrocyte membranes prepared by hypotonic hemolysis contained 5 to 15% of the phosphofructokinase in the erythrocytes. The membrane-bound phosphofructokinase can be eluted by a saline wash. Human erythrocyte and rabbit muscle phosphofructokinase bind to the saline-washed membranes. This binding is specific for the inner surface of the membrane. The amount of phosphofructokinase bound is dependent on pH; at pH 7, 6 times more enzyme is bound than at pH 7.5. Unlike free phosphofructokinase, the membrane-bound phosphofructokinase is not inhibited by ATP or 2,3-diphosphoglycerate, and its fructose-6-P saturation curve is nonsigmoidal.