Association of adiponectin promoter variants with traits and clusters of metabolic syndrome in Arabs: family-based study.

Plasma levels of adiponectin are decreased in type 2 diabetes, obesity and hypertension. Our aim was to use a family-based analysis to identify the genetic variants of the adiponectin (ADIPOQ) gene that are associated with obesity, insulin resistance, dyslipidemia and hypertension, among Arabs. We screened 328 Arabs in one large extended family for single nucleotide polymorphisms (SNPs) in the promoter region of the ADIPOQ gene. Two common SNPs were detected: rs17300539 and rs266729. Evidences of association between traits related to the metabolic syndrome and the SNPs were studied by implementing quantitative genetic association analysis. Results showed that SNP rs266729 was significantly associated with body weight (p-value=0.001), waist circumference (p-value=0.037), BMI (p-value=0.015) and percentage of total body fat (p-value=0.003). Up to 4.1% of heritability of obesity traits was explained by the rs266729 locus. Further cross-sectional analysis showed that carriers of the G allele had significantly higher values of waist circumference, BMI and percentage of total body fat (p-values 0.014, 0.004 and 0.032, respectively). No association was detected between SNP rs266729 and other clusters of metabolic syndrome or their traits except for HOMA-IR and fasting plasma insulin levels, p-values 0.035 and 0.004, respectively. In contrast, both measured genotype and cross-sectional analysis failed to detect an association between the SNP rs17300539 with traits and clusters of metabolic syndrome. In conclusion, we showed family-based evidence of association of SNP rs266729 at ADIPOQ gene with traits defining obesity in Arab population. This is important for future prediction and prevention of obesity in population where obesity is in an increasing trend.

Biodegradation of organophosphate pesticide chloropyrifos by Egyptian bacterial isolates.

Sixteen microbial isolates capable of growing on Dursban as a secondary substrate were isolated from three soil and sewage water samples collected from different localities polluted with pesticides. Six developed isolates only were capable of biodegrading Dursban and utilizing it as only sole source of carbon, energy and phosphorus. The six bacterial isolates were managed to grow on enrichment medium containing Dursban up to 40 ml/liter, for seven days at 25 degrees C. Each isolate exhibited growth and degradation of Dursban concentrations that best bacteria were identified as Pseudomonas stutzeri S7B4 and Flavobacterium balustinum S8B6. These two bacterial isolates were subjected to some environmental and nutritional parameters that affect the biodegradation process of Dursban. The optimum conditions includes :incubation period, 7 days; Dursban concentrations, 10 ml/l; inoculum size, 4 ml/l; incubation temperature, 35 degrees C; optimum pH value, 7; carbon source, fructose and ribose, respectively; nitrogen source, urea and peptone, respectively; amino acid, histidine; and vitamin, yeast extract, under shaking condition (200 rpm). Only the most potent microbial isolate Pseudomonas stutzeri was grown on their own mineral salts medium which contained 40 mlM/l in case of Dursban in the absence and presence of fructose as the best carbon source for two time intervals i.e. 7 and 15 days. Absence of phosphorus and the presence of many oxidized compounds revealed that the ability of P. stutzeri to biodegrade and detoxify Dursban using it as the sole phosphorus, carbon and energy sources. GC-MS analysis of all three treatments of Dursban-bioremediation process showed no detection of any phosphorus compounds especially Dursban in the three treatments, indicated that both bacterial strains i.e. P. stutzeri S7-B4 and F. balustinum S8B6 were able to utilize Dursban pesticide as carbon and phosphorus sources. Thus, it is possible to use both bacterial strains in the bioremediation of pesticides especially Dursban-contaminated sites.

A novel locus for hereditary spastic paraplegia with thin corpus callosum and epilepsy.

BACKGROUND: Hereditary spastic paraplegia (HSP) are classified clinically as pure when progressive spasticity occurs in isolation or complicated when other neurologic abnormalities are present. At least 22 genetic loci have been linked to HSP, 8 of which are autosomal recessive (ARHSP). HSP complicated with the presence of thin corpus callosum (HSP-TCC) is a common subtype of HSP. One genetic locus has been identified on chromosome 15q13-q15 (SPG11) for HSP-TCC, but some HSP-TCC families have not been linked to this locus. METHODS: The authors characterized two families clinically and radiologically and performed a genome-wide scan and linkage analysis. RESULTS: The two families had complicated ARHSP. The affected individuals in Family A had thin corpus callosum and mental retardation, whereas in Family B two of three affected individuals had epilepsy. In both families linkage analysis identified a locus on chromosome 8 between markers D8S1820 and D8S532 with the highest combined lod score of 7.077 at marker D8S505. This 9 cM interval located on 8p12-p11.21 represents a new locus for ARHSP-TCC. Neuregulin and KIF13B genes, located within this interval, are interesting functional candidate genes for this HSP form. CONCLUSION: Two consanguineous families with complicated autosomal recessive hereditary spastic paraplegia were clinically characterized and genetically mapped to a new locus on 8p12-p11.21.

A family study in Oman: large, consanguineous, polygamous Omani Arab pedigrees.

OBJECTIVE: To establish a suitable human model for the study of the genetics of complex diseases. METHODS: We have selected an Omani Arab population to provide the statistical power required to study the genetics of complex diseases with confidence. This model consists of five multigenerational highly inbred pedigrees, descending from a small number of founders just a few generations ago with environmental homogeneity, restricted geographical distribution, detailed records and well-ascertained and -validated pedigrees. Stringent criteria were adopted for defining the phenotypes of hypertension, diabetes mellitus, dyslipidemias and obesity. The SOLAR genetic software package was used to draw the pedigree structure. RESULTS: Outstanding statistical power to detect susceptibility loci was obtained. CONCLUSIONS: This model represents a large homogeneous human family-based population for the study of genetic and environmental factors contributing to complex diseases.

Diversity in expression of glucose-6-phosphate dehydrogenase deficiency in females.

The aims of this study were to determine the prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency in the United Arab Emirates (UAE), to describe the different mutations in the population, to determine its prevalence, and to study inheritance patterns in families of G6PD-deficient individuals. All infants born at Tawam Hospital, Al-Ain, UAE from January 1994 to September 1996 were screened at birth for their G6PD status. In addition, those attending well-baby clinics during the period were also screened for the disorder. Families of 40 known G6PD-deficient individuals, selected randomly from the records of three hospitals in the country, were assessed for G6PD deficiency. Where appropriate, this was followed by definition of G6PD mutations. Of 8198 infants, 746 (9.1%), comprising 15% of males and 5% of females tested, were found to be G6PD deficient. A total of 27 families were further assessed: of these, all but one family had the nt563 Mediterranean mutation. In one family, two individuals had the nt202 African mutation. The high manifestation of G6PD deficiency in women may be due to the preferential expression of the G6PD-deficient gene and X-inactivation of the normal gene, and/or to the presence of an 'enhancer' gene that makes the expression of the G6PD deficiency more likely. The high level of consanguinity which, theoretically, should result in a high proportion of homozygotes and consequently a higher proportion of females with the deficiency, was not found to be a significant factor.

The association of Hb Khartoum [beta124(H2)Pro-->Arg] with gamma+-thalassemia is responsible for hemolytic disease in the newborn of a Sudanese family.

The unstable Hb Khartoum with a Pro-->Arg replacement at position beta124 was identified by isoelectrofocusing, high performance liquid chromatography, and peptide mapping in a mother and two male children of a Sudanese family. All three were heterozygous for the abnormal hemoglobin; the father and a third male child did not carry the mutation. The mother was also homozygous for two putative gamma+-thalassemia point mutations, one affecting both Agamma and Ggamma genes at IVS-II-115 (A-->G), and one affecting the Ggamma gene at the 3' untranslated region (-A) at position -6 from the polyadenylation site. The father had normal gamma genes. All three children were heterozygous for both the gamma+-thalassemia mutations. The two older children, who were compound heterozygotes for Hb Khartoum/gamma+-thalassemia, presented at birth with severe neonatal jaundice which necessitated exchange blood transfusions. Other causes of neonatal jaundice were excluded. The third male child, who did not carry the Hb Khartoum anomaly but was heterozygous for gamma+-thalassemia, did not develop neonatal jaundice. It is concluded that the instability of Hb Khartoum in combination with gamma+-thalassemia is responsible for neonatal hemolytic anemia in this family.

Epidemiology of clinical hyperbilirubinaemia in Al Ain, United Arab Emirates.

All infants born at Al Ain Hospital, United Arab Emirates between 1 January and 30 June 1995 who developed clinically relevant hyperbilirubinaemia defined as jaundice requiring investigation and treatment were prospectively studied. Of the 2300 live births, 85 (3.7%) developed hyperbilirubinaemia. Of these, 22 were premature, 22 had ABO haemolytic disease of the newborn, eight had G6PD deficiency (Mediterranean), seven had breast-milk jaundice, five were born to mothers with diabetes mellitus and one had Rh incompatibility. No specific factor was identified in 20 (24%). Significant differences in the distribution of diagnostic categories were found among the major ethnic groups in the population studied. This first study of the epidemiology of clinically relevant hyperbilirubinaemia in this community identified locally relevant risk factors and highlighted areas of health care which, if modified, might reduce the incidence of hyperbilirubinaemia.

PIP: If untreated, severe unconjugated hyperbilirubinemia is neurotoxic. Management of the condition therefore includes preventing serum bilirubin from reaching toxic levels. Identifying infants at risk of developing severe hyperbilirubinemia and early intervention have reduced levels of morbidity and mortality associated with bilirubin encephalopathy. The incidence of neonatal jaundice and the etiological factors associated with hyperbilirubinemia vary by locale. All infants born at Al Ain Hospital, United Arab Emirates, between January 1 and June 30, 1995, who developed clinically relevant hyperbilirubinemia defined as jaundice requiring investigation and treatment were prospectively studied. 85 (3.7%) of the 2300 live births developed hyperbilirubinemia. Of those, 22 were premature, 22 had ABO hemolytic disease of the newborn, 8 had G6PD deficiency (Mediterranean), 7 had breast milk jaundice, 5 were born to mothers with diabetes mellitus, and 1 had Rh incompatibility. No specific factor was identified in 20 (24%) infants. Significant differences in the distribution of diagnostic categories were found among the major ethnic groups in the population studied.

Antibody responses to Rhoptry-Associated Protein-1 (RAP-1) of Plasmodium falciparum parasites in humans from areas of different malaria endemicity.

Plasma IgM and IgG antibody reactivities against the recombinant Plasmodium falciparum protein, Rhoptry Associated Protein-1 (rRAP-1) were measured by ELISA in individuals from Sudan, Indonesia, Kenya and The Gambia living in areas of different malaria endemicity. IgG and IgM reactivities to rRAP-1 increased with malaria endemicity. IgG reactivities were associated with spleen rates in Indonesia with high malaria endemicity while IgM reactivities were associated with spleen rates in Kenya with low malaria endemicity. IgG and IgM reactivities to rRAP-1 increased during acute episodes of P. falciparum malaria in Sudanese adults and IgG reactivities remained high one month after treatment in all adults tested. Antibody reactivities to rRAP-1 in Gambian children in the dry season were higher in children with parasitaemia than in children without detectable parasitaemia. Antibody reactivities were not associated with protection against clinical episodes in the following rainy season but higher antibody reactivities were detectable at the end of the rainy season. There was no difference in antibody reactivity to rRAP-1 between Gambian children with mild or severe malaria.

Soluble haemoglobin is a marker of recent Plasmodium falciparum infections.

Monoclonal antibodies (Mab) were raised against haemoglobin (Hb) associated with Plasmodium falciparum protein and used to develop an ELISA, measuring circulating levels of released Hb. This assay was evaluated in different malaria patients in parallel with ELISA assays for C-reactive protein (CRP) and haptoglobin. Levels of Hb were negatively associated with levels of haptoglobin. Increased levels of serum Hb and CRP and decreased levels of haptoglobin were seen in Danish malaria patients. Consecutive studies showed that increased Hb levels were detectable 3-7 days after initiation of treatment probably because of drug induced destruction of infected erythrocytes. Increased levels of CRP were measured 0-3 days after initiation of treatment. The Hb assay was used in an epidemiological study of malaria in an area of Sudan with unstable malaria transmission. The proportion of Sudanese adults with detectable soluble Hb was higher in the rainy season with malaria transmission compared to the dry season. Hb levels in the rainy season were negatively associated with levels of haptoglobin. Most adults had increased levels of soluble Hb and decreased levels of haptoglobin 7 and 30 days after their treatment of P. falciparum malaria compared to the levels during acute disease. Thus, both soluble Hb and haptoglobin appear to be markers of recent P. falciparum infections. Very high levels of CRP protein were measured in some of the malaria patients at the day of treatment while lower levels were recorded 7 and 30 days after treatment. Soluble Hb levels were associated with malariometric parameters in a similar fashion to haptoglobin. The new Mab-based assay for measuring soluble Hb in the peripheral blood of malaria patients may be useful for future epidemiological studies of malaria.

United Arab Emirates population data on three DNA tetrameric short tandem repeat loci: HUMTHO1, TPOX and CSF1PO--derived using multiplex polymerase chain reaction and manual typing.

Allele and genotype frequencies for three tetrameric short tandem repeat (STR) loci: HUMTHO1, TPOX, and CSFIPO, were determined in a United Arab Emirates (UAE) national population sample (n = 119). The loci were amplified simultaneously and the PCR products were separated in polyacrylamide DNA sequencing gels. Detection of the DNA fragments was accomplished using silver staining. Allele designations were determined by comparison to an allelic ladder. One allele at each locus was sequenced to confirm the nature of the repeats and their number. Alleles at the HUMTHO1 and TPOX loci were distributed bimodally, while CSF1PO showed unimodal distribution. The observed heterozygosities were 76% for HUMTHO1, 64% for TPOX, and 71% for CSF1PO. No deviation from the Hardy-Weinberg expectations was observed in the genotype distribution for the loci TPOX and CSF1PO, but the HUMTHO1 locus did depart from HWE based on the likelihood ratio and the exact test. No correlation was detected between the alleles at any of the three pairs of loci. The allelic frequency data of these three loci in the UAE population sample can thus be used in human identity testing.

Effect of previous chloroquine intake on in vivo P. falciparum drug sensitivity.

Investigation of the in vivo response of P. falciparum malaria parasites to chloroquine was conducted during 1993/94 in Al-Ain District of Abu Dhabi Emirate, UAE. Sixty seven expatriates who developed falciparum malaria on their return from Pakistan, Oman and Sudan were recruited for the WHO in vivo tests. Of the 67 patients, eight were classified as having RII and RIII responses, while 59 remained aparasitaemic at the end of the seven-day WHO standard test. On continuation into the 28-day WHO extended test, a further 34 patients exhibited RI resistance. Resistance of parasites to chloroquine was confirmed by measurement of plasma chloroquine using High-Performance Liquid Chromatography. In all 67 patients, the level of chloroquine was well above the minimum therapeutic level. The outcome of the in vivo test in patients treated for the first time was significantly different from that in patients who were previously on chloroquine. Among patients treated for the first time, 36 out of 41 (88%) had a resistant response, whereas, among those previously on chloroquine only six out of 26 (23%) had a resistant response. The difference is probably due to the higher initial plasma level of chloroquine among patients who were previously on the drug. Curing more patients with higher plasma chloroquine implies that chloroquine shall continue to be useful, particularly if resistance is at the RI level. Appropriate higher therapeutic levels of chloroquine should be defined for such patients.

Polymorphic N-acetyltransferase (NAT2) genotyping of Emiratis.

Polymorphic N-acetyltransferase (NAT2) genotypes were determined in 106 unrelated Emiratis by PCR-RFLP analysis to obtain estimates of allele frequencies. Thirteen different genotypes were found, four associated with the rapid acetylator phenotype and nine with the slow acetylator phenotype. Among 67 phenotypically slow acetylators, there was 100% concordance between phenotype and genotype. Among 39 phenotypically rapid acetylators, 37 possessed at least one wild type allele; a 95% concordance with genotype. Seven different NAT2 alleles associated with slow acetylation were found. The commonest was a NAT2*5 type (C481T) allele which occurred with a frequency of 0.53, a significantly higher frequency than has been reported for other ethnic groups. A second slow allele, a NAT2*6 type (G590A), occurred with a frequency of 0.21. The most common genotypes found were NAT2*5/*5 homozygotes, NAT2*5/*6 heterozygotes and NAT2*4/*5 heterozygotes with frequencies of 0.25, 0.25 and 0.22 respectively. The high overall prevalence of alleles associated with slow acetylation (173/212; 81.6%) among Emiratis is consistent with previously reported high frequency of the slow acetylator phenotype in Arabs. Two apparently new slow alleles were identified but have not yet been fully characterized. One appears to be a NAT2*5 variant allele. The other uncharacterized allele appears likely to contain an entirely new mutation associated with slow acetylation.

Does the mechanism of protection from falciparum malaria by red cell genetic disorders involve a switch to a balanced TH1/TH2 cytokine production mode?

The mechanism of protection from falciparum malaria by red cell genetic disorders still remains controversial. Decreased survival of parasites in variant red cells has previously been proposed. However, in vitro experiments were not conclusive and do not seem sufficient to explain the substantial degree of in vivo protection afforded to red cell genetic trait carriers. Evidence has recently been accumulating in favour of enhancement of the host immune response by these genetic traits. Malaria-infected variant red cells undergo modifications to their antigenicity which lead to accelerated and selective removal of early blood-stage parasites by splenic macrophages, resulting in fewer parasites reaching schizogony. Consequently there will be alterations in antigen processing, presentation and recognition which could explain the differences observed in T-cell responses between trait carriers and normal individuals. It is suggested that exposure to a lower dose of early parasite-stage antigens rather than the exoantigens of late mature schizonts could lead during primary and subsequent secondary infections to differentiation of T-helper cells into balanced TH1/TH2 subsets that promote protection, reversing the susceptibility to the fatal complications of falciparum malaria.

Antibody reactivities to glutamate-rich peptides of Plasmodium falciparum parasites in humans from areas of different malaria endemicity.

Synthetic P. falciparum peptides were evaluated as tools in epidemiological investigations of malaria. Plasma IgM and IgG antibody reactivities against synthetic peptides covering sequences of glutamate-rich protein (GLURP) and acidic-basic repeat antigen (ABRA) were measured by ELISA in individuals from malaria-endemic areas of Sudan, Indonesia and The Gambia to study antibody responses to these peptides in donors living in areas of different malaria endemicity. IgG and IgM reactivities to the peptides increased with malaria endemicity, although there were no differences in reactivities to the GLURP peptide between non-exposed donors and donors living in areas of low malaria endemicity. IgG reactivities to the GLURP peptide in Sudanese adults were high one month after treatment in all adults tested, while IgG reactivities to the ABRA peptide were infrequent. IgM responses to the peptides tested were shortlived in most patients. In Gambian children with malaria, IgM reactivities but not IgG antibody reactivities against the ABRA peptide were higher in those with mild malaria than in those with severe malaria. The peptides may be useful in future epidemiological studies, especially in areas of low malaria endemicity.

Molecular characterization of erythrocyte glucose-6-phosphate dehydrogenase deficiency in Al-Ain District, United Arab Emirates.

In a cross-sectional study, the activity, electrophoretic mobility and genotypes of glucose-6-phosphate dehydrogenase (G6PD) were determined among healthy, UAE national school boys from Al-Ain District in the United Arab Emirates, The prevalence of G6PD deficiency in this population sample was 11%. The majority of G6PD-deficient subjects were descendants of Omani, Baluchi or Yemeni migrants. Of 18 deficient subjects, 16 had an enzyme activity of < 10% of normal while 2 had an activity of just above 10%. Electrophoresis was performed on 166 samples and showed that, apart from deficient samples, all had the normal mobility of G6PD type B. Of the 18 deficient subjects, 14 had the B type mobility of G6PD Mediterranean and 4 had the A type mobility of G6PD A-. Genotyping demonstrated that 10 had the Mediterranean mutation while 3 had the A- mutation, consistent with their electrophoretic mobility. Another 3 had the G6PD Aures mutation, recently described as polymorphic in Algeria and Spain. The mutations in the remaining 2 subjects have not yet been identified.

Uptake and efflux of chloroquine by chloroquine-resistant Plasmodium falciparum clones recently isolated in Africa.

In recently isolated African Plasmodium falciparum clones, the intracellular chloroquine concentration at steady-state, under standard culture conditions, could not differentiate chloroquine-sensitive from resistant parasites. However, under an atmosphere of air the chloroquine-resistant P. falciparum clones released pre-accumulated [3H]chloroquine more rapidly than sensitive clones. The very fast efflux of the pre-accumulated drug from chloroquine-resistant (CQR) parasites resulted in a differential in the drug retained by resistant and sensitive parasites. The chloroquine-sensitive parasites retained 2-3 times more chloroquine than resistant parasites. The steady-state uptake of [3H]chloroquine appeared to be enhanced by verapamil and desipramine in the chloroquine-resistant clones, while the opposite was observed with sensitive clones. This confirmed the suggestion that verapamil inhibits the rapid efflux in CQR parasites resulting in a readily detectable increase in chloroquine accumulation. These observations indicate that the biochemical phenotypes of African chloroquine-resistant P. falciparum are similar to those reported from S.E. Asia and Latin America and are consistent with a common molecular basis for the phenomenon.