Affected sib-pair analysis of the GLUT1 glucose transporter gene locus in non-insulin-dependent diabetes mellitus (NIDDM): evidence for no linkage

Despite the strong evidence for a major role played by genetic factors in the aetiology of non-insulin-dependent diabetes mellitus (NIDDM), the genes involved are still unknown. Association studies of candidate genes for the inheritance of NIDDM have so far yielded inconclusive results. Some evidence exists for an association between NIDDM and the glucose transporter gene GLUT1, involved in basal glucose transport, although this has not been confirmed. In the present study we have tested the hypothesis of linkage between NIDDM and the GLUT1 gene, using affected sib-pairs. With this method the concordance observed for a given gene marker is compared with that expected under the assumption of no linkage between that marker and the disease. Fifty-four pedigrees (22 Italians and 32 British), for a total of 82 sibpairs were studied by the affected sib-pair method proposed by Weeks and Lange, using two restriction fragment length polymorphisms (RFLPs) at the GLUT1 locus, the MspI RFLP, at an estimated 0.171 recombination frequency from the GLUT1 gene, and the XbaI RFLP, located within the GLUT1 gene and previously shown to be associated with the disease. Results showed that the MspI marker and NIDDM segregate independently; for the XbaI RFLP, linkage could be shown only if the results were weighted by the allele frequency [f(p) = 1/p], and only in the Italian and the combined (Italian and British) sib-pair groups. Multilocus analysis with both markers was also negative. We conclude that the GLUT1 gene is very unlikely to play a major role in the aetiology of NIDDM, although an accessory role cannot be excluded, and studies of the gene sequence should help to clarify this question.     

High frequency of polymorphism but no mutations found in the GLUT1 glucose transporter gene in NIDDM and familial obesity by SSCP analysis

To evaluate whether a structural defect in the human glucose transporter gene GLUT1 could be involved in the aetiology of insulin resistance, a key factor of non-insulin-dependent diabetes mellitus (NIDDM) and obesity, we performed single-strand conformation polymorphism (SSCP) analysis in 40 subjects (20 NIDDM patients and 20 subjects with familial obesity). The GLUT1 gene, which is involved in basal glucose transport in most tissues, consists of ten exons and encodes a 492 amino acid protein. Population studies have shown a strong association between the X1 allele of an XbaI restriction fragment length polymorphism of the GLUT1 gene and NIDDM. We therefore performed SSCP analysis in NIDDM subjects known to carry at least one X1 allele. Variant SSCP patterns were detected in exons 2, 4, 5 and 9. Sequence analysis of the SSCP variants revealed the presence, in all exons examined, of silent mutations consisting of single-nucleotide substitutions with no amino acid changes. Both NIDDM and obese patients showed a high frequency of polymorphism in the sequence (50% and 35%, respectively). We conclude that the GLUT1 gene is unlikely to play a role in the aetiology of NIDDM and obesity. However, the strong association between the GLUT1 gene and NIDDM, together with the recent family studies showing linkage between chromosome 1p and NIDDM warrant further studies on this chromosomal region. Received: 18 August 1997 / Accepted: 10 December 1997     

Style morph frequencies in Minnesota populations of Lythrum (Lythraceae)

Style morph frequencies (shortmidlong) were determined for a total of n = 11 918 plants in 16 Minnesota populations of Lythrum salicaria L. Nine populations were in the establishment phase, with population sizes ranging from n = 56 to n = 2 192. Most of these populations exceeded previously reported population sizes in the native European habitat. A nonparametric statistical test, the chi-square (²), can be used to determine if populations are at isoplethic equilibrium (111, shortmidlong); a ² value >5.99 is significant at the 5% level. Only one established population (White Bear Lake, n = 1991, ² = 3.0) fitted the null hypothesis for isoplethy, although all established populations contained all three style morphs. Pooled values for these populations indicated an excess of mids and longs, with shorts being deficient. Colonizing populations had a higher percentage of mids (54%) when compared to established populations (33.7%). Short styles were almost nonexistent (8%) in colonizing populations. Five out of the seven populations lacked at least one style morph. A review of the literature reporting style morph frequencies in tristylous L. salicaria revealed that no statistical analysis for isoplethy has been performed. Darwin originally assumed that all populations would be isoplethic, possessing equal numbers of all three style morphs, but concluded, without statistical analysis, that, instead, populations were anisoplethic. Since tests for statistical deviations from the expected frequencies (111) have not been used, ² analysis was performed. Several of these populations were at isoplethic equilibrium (Nadder su2 = 1.7, Blelham ² = 1.69, Potsdam ² = 1.5, Vestfold ² = 0.4, Buskerud ² = 5.62, Kilchberg ² = 0.35, Lausanne ² = 3.32, Canberra ² = 5.29, Massachusetts ² = 3.13), suggesting that the general conclusion of anisoplethy in tristylous L. salicaria is inappropriate.This is Scientific Journal Series Paper Number 19 128 of the Minnesota Agricultural Experiment Station     

Elevated frequency of an ETS-1 restriction fragment polymorphism in chronic B-cell leukaemia

We studied the frequency of an SstI polymorphism in 70 patients with chronic B-cell leukaemia (CLL) and 100 normal controls. There was a highly significant difference in the distribution of the three genotypes between the CLL patients and the normal controls (²= 13.46, 2 df, P<0.001). The C2 allele was found more frequently in CLL patients and may be a marker for a predisposition to develop CLL.     

Alcohol dehydrogenase genes: restriction fragment length polymorphisms for ADH4 (π-ADH) and ADH5 (χ-ADH) and construction of haplotypes among different ADH classes

Of the five human alcohol dehydrogenase (ADH) genes located in the region q21–25 of chromosome 4, genetic markers have been reported previously only for class I enzymes, ADH1-3. Here, new restriction fragment length polymorphisms (RFLPs) are described for the genes of two other classes, ADH4 () and ADH5 ( or formaldehyde dehydrogenase, FDH). The frequencies and modes of inheritance of these RFLPs were determined with DNA both from unrelated individuals and from families. A polymorphic PstI site is assigned to the fourth intron of the ADH4 gene. Pairwise linkage disequilibrium calculations for these new RFLPs and already known RFLPs at the ADH2 and ADH3 loci establish strong linkage disequilibria between polymorphic MspI and BstXI sites in the ADH5 gene as well as between XbaI and MspI sites in the ADH3 gene. Furthermore, linkage disequilibria were detected between RFLPs of the ADH2 and ADH3 genes as well as between those of the ADH4 and ADH5 genes. The latter disequilibrium implies a hitherto unknown physical proximity of two genes belonging to different ADH classes. The RFLPs were used to construct chromosomal haplotypes that include three ADH classes. Of the 16 possible haplotypes for four RFLP markers used here, 10 were experimentally detected. The potential application of the ADH RFLPs and haplotypes in linkage or association studies of inherited diseases such as familial alcoholism is discussed.     

Polymorphism of Glutathione S-Transferase M1 and P1 in Patients with Cystic Fibrosis and Chronic Respiratory Diseases

Polymorphism of GSTM1 and GSTP1 genes was studied in patients with cystic fibrosis (CF) and chronic bronchopulmonary diseases (CBPD) living in Bashkortostan. A combination of certain GSTM1 and GSTP1 genotypes accompanied by severe mutations inCFTRgene proved to intensify a pathologic process in respiratory organs of patients with CF; a combination of the normal GSTM1 and heterozygous I/V GSTP1 genotypes is the most favorable (OR = 4.49; ² = 11.53, P < 0.002). In patients with CBPD, a combination of the GSTM1null genotype and the homozygous GSTP1 V/V genotype is the most common (5.5% versus 1.3% in control; ² = 3.01, P = 0.08). The frequency of this genotype is highest in groups of patients with recurrent bronchitis (8.1%; P = 0.07; OR = 6.75) and bronchiectatic disease (BED) (9.1%, P > 0.10, OR = 7.65). A combination of the null GSTM1 andI/V GSTP1 genotypes was found in 40.0% of patients with chronic nonobstructive bronchitis (² = 4.87; P = 0.03; OR = 4.03). Among patients with BED, a proportion of individuals with the normal GSTM1 and I/V GSTP1 genotypes was increased (36.4% versus 19.4% in control). In patients with chronic obstructive pulmonary disease (COPD), the frequencies of the GSTM1 and GSTP1 genotype combinations virtually did not differ from those in the control group suggesting that COPD severity is not related to changes in activities of glutathione S-transferases M1 and P1.     

Genetic Determinants of Predisposition to Bronchial Asthma

The ratio between the normal (+) and null (0) alleles of the genes encoding glutatione S-transferases M1 (GSTM1) and T1 (GSTT1) were studied in normal individuals from northwestern Russia (control group) and in patients with bronchial asthma (BA). The frequency of the GSTM1 0/0 genotype in the population sample was statistically significantly lower (37.8%) than in the BA patients (82.1%; ² = 16.8;P< 0.001; _W² = 15.7; = 0.01). For the GSTT1 gene, similar data were obtained. The frequency of the GSTT1 0/0 genotype in healthy donors was statistically significantly higher (16.3%) than in the BA patients (73.7%; ² = 28.5;P < 0.001; _W² = 23.22; = 0.01). A significant preponderance of the compound homozygotes for the GSTM1 and GSTT1 null alleles among the BA patients was observed. The frequency of the GSTM1 0/0, GSTT10/0 individuals among the patients was 57.9%, while it was only 4.7% among the controls (² = 27.4; P < 0.001).     

The breeding cycle of Scylla serrata (Forskal, 1755) at Ramisi River estuary,Kenya

The mud crab Scylla serrata was collected from Ramisi river estuaryfor a period of 14 months (January 1990–February 1991) using madema traps. For each crab, the carapace width (mm), sex and weightwere noted, and the number of ovigerous female crabs was recorded. Both ovigerous and non-ovigerous females were dissected in order to observeof the maturity stages of ovaries. The ovarian maturity stages weredescribed as stage zero – virgin/resting, stage one – developing, stage two– well developed and stage thre e– ripe. The most abundant was stage twothroughout the study period. The smallest ovigerous crab had a carapacewidth of 139 mm. A test of homogeneity of the binomial distributionof the sex ratio showed homoscedasticity (² = 14.615; d.f. = 13; p> 0.05) and the overall sex ratio did not differ from 1:1 (² = 0.776; d.f. = 1; p> 0.05). The variance test ofhomogeneity of the binomial distribution of sex in relation to size showeda very significant heterogeneity (² = 32.83; d.f. = 9; p< 0.05). There was no significant difference when the overall mean sizesfor males and females were compared using t-test (t = 4.26; d.f. = 18;p< 0.001). The relatively high numbers of females with stage two ovariesindicated that spawning took place throughout the year with a possible peakin the second half of the year.     

Polymorphisms in the apolipoprotein B-100 gene contributes to normal variation in plasma lipids in 464 Danish men born in 1948

We have studied the possible association of 5 polymorphisms in the apoB gene [a 9-bp insertion/deletion length polymorphism in the signal peptide coding region, XbaI, MspI, and EcoRI restriction fragment length polymorphisms (RFLPs) and a 15-bp variable number of tandem repeats (VNTR) region 3 to the apoB gene] with plasma concentrations of cholesterol, high density lipoprotein cholesterol, triglycerides and apolipoprotein B-100 in 464 randomly selected Danish men born in 1948. The XbaI RFLP and the insertion/deletion length polymorphism were significantly associated with plasma concentration and inter-individual variation of cholesterol and apolipoprotein B-100 (1.77% and 1.37% of sample variance in cholesterol, and 1.4% and 1.39% of sample variance in apoB). The association was particularly strong in men with a body mass index less than 25 kg/m² (the mean value of the whole cohort) (3.43% and 2.93% of sample variance in cholesterol, and 3.1% and 2.13% of sample variance in apoB). The XbaI RFLP and the insertion/deletion length polymorphism were in strong linkage disequilibrium, explaining why independent associations of these two polymorphisms with cholesterol and apoB could not be established. There were no other associations between apoB gene polymorphisms and lipoprotein components.     

Estimation of the Stationary Gene Migration Rate: A Cartographic Approach

A method of geographic mapping of the stationary (limiting) gene migration rate has been developed. The method is based on approximation of the empirical distribution of gene frequencies by a theoretical steady-state distribution. The maximum likelihood method and the ² minimization method are used to obtain consistent estimations of the gene migration rate as a parameter of the steady-state distribution. The new method makes it possible to determine the geographical distribution of the ratio between the properties of the population migration structure described by the stepping-stone and island models and to construct a geographical map of ² values. This map approximately reflects the distribution of natural selection pressure on the gene pool if genetic processes are quasisteady.     

ATM and GLUT1-S490 Phosphorylation Regulate GLUT1 Mediated Transport in Skeletal Muscle

Objective

The glucose and dehydroascorbic acid (DHA) transporter GLUT1 contains a phosphorylation site, S490, for ataxia telangiectasia mutated (ATM). The objective of this study was to determine whether ATM and GLUT1-S490 regulate GLUT1.

Research Design and Methods

L6 myoblasts and mouse skeletal muscles were used to study the effects of ATM inhibition, ATM activation, and S490 mutation on GLUT1 localization, trafficking, and transport activity.

Results

In myoblasts, inhibition of ATM significantly diminished cell surface GLUT1, glucose and DHA transport, GLUT1 externalization, and association of GLUT1 with G_α-interacting protein-interacting protein, C-terminus (GIPC1), which has been implicated in recycling of endosomal proteins. In contrast, ATM activation by doxorubicin (DXR) increased DHA transport, cell surface GLUT1, and the GLUT1/GIPC1 association. S490A mutation decreased glucose and DHA transport, cell surface GLUT1, and interaction of GLUT1 with GIPC1, while S490D mutation increased transport, cell surface GLUT1, and the GLUT1/GIPC1 interaction. ATM dysfunction or ATM inhibition reduced DHA transport in extensor digitorum longus (EDL) muscles and decreased glucose transport in EDL and soleus. In contrast, DXR increased DHA transport in EDL.

Conclusions

These results provide evidence that ATM and GLUT1-S490 promote cell surface GLUT1 and GLUT1-mediated transport in skeletal muscle associated with upregulation of the GLUT1/GIPC1 interaction.     

Intestinal Dehydroascorbic Acid (DHA) Transport Mediated by the Facilitative Sugar Transporters,GLUT2 and GLUT8

Intestinal vitamin C (Asc) absorption was believed to be mediated by the Na⁺-dependent ascorbic acid transporter SVCT1. However, Asc transport across the intestines of SVCT1 knock-out mice is normal indicating that alternative ascorbic acid transport mechanisms exist. To investigate these mechanisms, rodents were gavaged with Asc or its oxidized form dehydroascorbic acid (DHA), and plasma Asc concentrations were measured. Asc concentrations doubled following DHA but not Asc gavage. We hypothesized that the transporters responsible were facilitated glucose transporters (GLUTs). Using Xenopus oocyte expression, we investigated whether facilitative glucose transporters GLUT2 and GLUT5–12 transported DHA. Only GLUT2 and GLUT8, known to be expressed in intestines, transported DHA with apparent transport affinities (K_m) of 2.33 and 3.23 mm and maximal transport rates (V_max) of 25.9 and 10.1 pmol/min/oocyte, respectively. Maximal rates for DHA transport mediated by GLUT2 and GLUT8 in oocytes were lower than maximal rates for 2-deoxy-d-glucose (V_max of 224 and 32 pmol/min/oocyte for GLUT2 and GLUT8, respectively) and fructose (V_max of 406 and 116 pmol/min/oocyte for GLUT2 and GLUT8, respectively). These findings may be explained by differences in the exofacial binding of substrates, as shown by inhibition studies with ethylidine glucose. DHA transport activity in GLUT2- and GLUT8-expressing oocytes was inhibited by glucose, fructose, and by the flavonoids phloretin and quercetin. These studies indicate intestinal DHA transport may be mediated by the facilitative sugar transporters GLUT2 and GLUT8. Furthermore, dietary sugars and flavonoids in fruits and vegetables may modulate Asc bioavailability via inhibition of small intestinal GLUT2 and GLUT8.     

Einfluß von Bromuracil auf die Mutationsauslösung und Inaktivierung durch UV und Röntgenstrahlen beim Phagen χ

Zusammenfassung Durch Anreicherung in BUdR- und FUdR-haltigem Medium wurde in die DNS des Serratiaphagen Bromuracil (BU) eingebaut. Im CsCl-Gradienten zeigte die Dichte der BU--Partikel einen Ersatz des Thymins durch BU von 25 bis 30% an. Die Häufigkeit zweier Plaquetypmutanten (c und b) war in der BU--Population signifikant (durchschnittlich 1,4 bzw. 2,4), die des dritten Typs (e) nur insignifikant über die in BU-freien Phagen erhöht. Im Vergleich zu letzterem betrug die absolute Häufigkeit der zusätzlichen c- und b-Mutanten in BU- 2,2 × 10^–4 bzw. 1,1 × 10^–4.Die UV-Inaktivierung von BU- war etwa um den Faktor 1,40 höher als die des normalen . Die Inaktivierung durch Röntgenstrahlen war dagegen nur um das 1,14fache erhöht. Die Häufigkeit der durch Röntgenstrahlen induzierten Plaquemutationen wurde durch den BU-Einbau nicht merklich beeinflußt. Dagegen war die UV-Induktion der Mutationen sehr viel mehr verstärkt als die UV-Inaktivierung. Die Sensibilisierungsfaktoren der drei Mutantentypen waren verschieden und am höchsten bei niederen UV-Dosen (3,4, 5,0 und 22 für c, b bzw. e). Das bedeutet eine Annäherung der Dosiskurven an linearen Verlauf. Die zur Auslösung von Mutationen erforderliche Trefferzahl wird somit durch BU-Einbau vermindert. Für -normal entsprachen die Kurven der UV-Mutationsinduktion dem 2-Treffertyp. Es wird geschlossen, daß die Hemmung der Dunkelreaktivierung (HCR) der Letalläsionen und Prämutationen in BU-DNA nicht die einzige Ursache für die Unterschiede in den UV-Sensibilitäten ist, sondern daß die Bildung anderer UV-Produkte als in der normalen DNA ebenfalls eine Rolle spielt.

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Summary Bromouracil (BU) was incorporated into the DNA of theSerratiaphage by means of culture in a medium with BUdR and FUdR. The density of BU-x particles in the CsCl-gradient indicated a replacement of about 24 to 32 % of the thymine by BU. The frequency of two types of plaquemutants (c and b) in the BU--population was increased significantly above the frequencies in BU-free phage by average factors of 1.4 and 2.4, resp. A third mutant type (e) was increased less. The absolut frequencies of additional c- and b-mutants in BU- compared with normal were about 2.10^–4 and 1.10^–4, resp.The UV-inactivation of BU- was higher by a factor of about 1.40 than that of normal , the inactivation by X-rays was only 1.14 times higher. The X-ray induced plaquemutation frequencies were not remarkably influenced by incorporated BU, but UV-mutation-induetion was increased much stronger than UV-inactivation. The sensitization factors were different for the three mutation types and highest at low UV-doses (3.4, 5.0 and 22 for c, b and e resp.). The UV-dose curves of mutation induction in normal are of the 2 hit type, but for BU- they were significantly less curved indicating the participation of 1-hit-processes in premutation production. It is concluded that inhibition of dark repair (HCR) of lethal lesions and premutations in BU-DNA is not the only reason for the differences in UV-sensitivities but that production of other species of UV-products in BU-DNA than in normal DNA plays also a role.

     

Analysis of the N-Acetyltransferase 2 Gene Polymorphism in the Patients with Chronic Obstructive Pulmonary Disease and in Populations of the Volga–Ural Region

Restriction fragment-length polymorphism of the gene coding for N-acetyltransferase 2 (NAT2) was typed in populations of the Volga–Ural region (Bashkirs, Tatars, Chuvashes, Udmurts, and Russians) as well as in patients with chronic obstructive pulmonary disease (COPD) and in healthy individuals. Rapid and slow acetylator phenotypes were determined based on the presence or absence of the KpnI, TaqI, and BamHI restriction endonuclease recognition sites. The proportion of slow acetylators in the populations examined varied from 40.00% in Bashkirs to 64.15% in Chuvashes with statistically significant difference between these two ethnic groups (² = 5.7; P = 0.02). Overall, in the Volga–Ural populations slow acetylators represented 56.25% of the subjects examined. This value was similar to those presented in other studies of Caucasoid populations. In the COPD patients a statistically significant decrease of the slow acetylator frequency to 48.28% compared to healthy individuals (62.18%) was observed (² = 4.60; P = 0.036). The data obtained suggest a possible association between the drug resistance in the COPD patients with the rapid acetylator phenotype, which can lead to the development of the chronic form of the disease.     

Apolipoprotein B amino acid 3611 substitution from arginine to glutamine creates the Ag (h/i) epitope: the polymorphism is not associated with differences in serum cholesterol and apolipoprotein B levels

Summary A G-to A-DNA sequence change in exon 26 of the human apolipoprotein B (apo B) gene leads to a glutamine substitution for arginine at codon 3611 of the mature apolipoprotein B100 and causes a loss of an MspI site. In 106 Finnish individuals, a complete correspondence exists between this MspI polymorphic site and the Ag (h/i) immunochemical polymorphism. Linkage disequilibrium was found between this MspI polymorphic site and the apo B XbaI and EcoRI variable sites and the Ag (a1/d) and (c/g) epitope pairs; there is apparent linkage equilibrium with the apo B PvuII variable site. Based on three population studies (samples from London, Finland and Italy), no significant association was found between this RFLP and serum cholesterol and apo B levels. These data suggest that the arginine 3611glutamine 3611 substitution has no significant effect on apo B function.     

The polymorphism ApoB/4311 in patients with myocardial infarction and controls: the ECTIM study

Summary The polymorphism affecting codon 4311 of the apolipoprotein B gene (ApoB/4311) was investigated in a large case-control study in two French and one Northern Irish geographically defined populations. Cases were recruited 3 to 9 months after a myocardial infarction (MI) and controls were randomly selected from the population. The polymorphism was assessed using allele-specific oligonucleotides (ASO). The genotype frequencies of the ApoB/4311 polymorphism did not differ in Northern Ireland and France and were in Hardy-Weinberg equilibrium in all groups; strong associations with three other polymorphisms of the ApoB gene (XbaI, EcoRI, VNTR(34 repeats)) were observed and it was possible to identify highly sensitive and specific markers of the ApoB/4311 rare variant. Homozygotes for the ApoB 4311 rare variant were slightly less frequent in cases than in controls: 22 (4.4%) and 35 (6.7%) respectively (population adjusted ²=3.3 P<0.07), especially in Belfast: 6 (3.1%) and 12 (7.6%), respectively (P<0.06). Several lipid and lipoprotein parameters were measured. Consistently among control groups, rare homozygotes had lower mean levels of ApoB (P<0.02), triglycerides (P<0.02), and lipoprotein particles containing ApoE and ApoB (LpE:B; P<0.001) and a higher mean level of lipoprotein particles containing ApoAI and not ApoAII (LpAI; P<0.02) than heterozygotes and frequent homozygotes combined. The strong association between the ApoB/4311 polymorphism and LpE:B was also observed in patients with MI. When present in the homozygous form, the ApoB/ 4311 AsnSer variant is associated with a lipoprotein profile that is apparently favourable.     

Structural and evolutionary comparisons of four alleles of the mouse immunoglobulin kappa chain gene,Igk-VSer

The mouseIgK-VSer gene encodes an immunoglobulin light chain variable region which gives rise to two phenotypic polymorphisms of mouse chains. The nucleotide sequences of coding and flanking regions of theIgk-VSer ^c andIgk-VSer ^d alleles found in recently inbred strains of wild mice are compared with those of theIgk-VSer ^a andIgk-VSer ^b alleles described previously. Results suggest that the gene is evolving randomly and that framework 2 and complentarity determining region 2 are preserved, presumably for overall light chain structure. Results indicate that all four allels have an octamer motif upstream of the gene which should be functional and allow prediction of whether or not the product of the germ line gene will be detectable as either the I_B-peptide or Ef1^a phenotypic polymorphism. Southern hybridization of genomic DNA using as probe a 1-kbXba I-Xba I fragment located approximately 4 kb upstream of the BALB/cIgk-VSer ^b coding region demonstrated the presence of homologous DNA in mice bearing theIgk-VSer ^a allele and absence from mice bearing theIgk-VSer ^c andIgk-VSer ^d alleles. Nucleotide sequence comparison of BALB/c and SK/CamRk (Igk-VSer ^d ) DNA in this region demonstrated that BALB/c contained an insertion 2.4 kb in length which was absent from SK/CamRk. Both strains contain DNA homologous to the reverse complement of the mouse Bam5 repetitive element at the point of the insertion, with BALB/c containing approximately 70 nucleotides more of the element than SK/CamRk. Surprisingly, the strains containing DNA related to theXba I-Xba I probe are not those determined to be the most similar by nucleotide sequence comparisons and by the Phylogenetic Analysis Using Parsimony program. The evolutionary relationship of the alleles and a possible basis for the inconsistency presented by theXba I-Xba I fragment-related DNA are discussed.     

A distinct HLA-DRw8 haplotype characterizes patients with juvenile rheumatoid arthritis

We studied the first domain of the HLA-DRB1, HLA-DQA1, and HLA-DQB1 loci of 67 HLA-DRw8-positive Caucasians including 43 with early-onset pauciarticular juvenile rheumatoid arthritis (EOPA-JRA, alternatively known as early-onset pauciarticular juvenile chronic arthritis). Serology, restriction fragment length polymorphism (RFLP), and polymerase chain reaction (PCR) oligotyping revealed that 62, including all the EOPA-JRA patients, carried the HLA-DRB1*0801, DQA1*0401, DQB1*0402 genotype. Approximately onefifth of the controls carried atypical HLA-DRB1, HLA-DQA1, and/or HLA-DQB1 loci on their HLA-DRw8 haplotype confirmed by family studies. DNA sequences of HLA-DRB1, DQA1, and DQB1 alleles in patients and controls were identical to those previously reported. Disease association studies in 113 EOPA-JRA patients and 207 controls unselected for HLA-DRw8 revealed that the HLA-DRB1*0801, DQA1*0401, DQB1*0402 genotype was associated with a higher relative risk (RR) for disease (RR = 12.8, ² = 48.8, P < 10^–4) than was the serologically defined presence of HLA-DRw8 (RR = 8, ² = 39, P < 10^–4). Further analysis suggested that the DQ genes on HLA-DRw8 haplotypes are as likely as the DR genes to contribute to the pathogenesis of EOPA-JRA. This study increases to five the number of HLA-DR/DQ haplotypes identified in HLA-DRw8 Caucasians.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number M34308.     

Correlation between antibodies to Cowdria ruminantium (Rickettsiales) in cattle and the distribution of Amblyomma vector ticks in Zimbabwe

Cowdriosis, caused by Cowdria ruminantium, is transmitted by Amblyomma ticks, which are widely distributed in Zimbabwe. To assess the distribution of this disease in Zimbabwe, cattle either exposed to Amblyomma ticks or maintained in areas free from these ticks were tested for antibodies to Cowdria. A total of 324 sera were tested using competitive ELISA and the indirect fluorescent antibody test (IFAT). At diptanks in Amblyomma-infested areas 52% (n=95) and 26% (n=47) of sera were positive by cELISA and IFAT, respectively. At diptanks in Amblyomma-free areas 11% (n=125) and 10% (n=134) of sera were positive by cELISA and IFAT, respectively. The results were significantly different between Amblyomma-infested and tick-free areas (²=24.73, P0.005 for IFAT and ²=57.53, P0.005 for cELISA). High background readings in field sera, possibly due to cross-reactive antibodies to Ehrlichia spp., complicated the determination of a realistic cut-off point, especially in cELISA. On the basis of the distribution of Amblyomma ticks, currently a large part of Zimbabwe can be considered endemic for the disease.     

Allele Polymorphism of the Serotonin Transporter Gene and Clinical Heterogeneity of Depressions

Depression disorders are a clinically heterogeneous disease group. Their development is to a substantial extent underlain by dysfunction of the serotonin system, in particular, disturbed serotonin transport. The heterogeneity of depressions is associated, among other factors, with the age at disease onset. Allele polymorphism of the serotonin transporter (5-HTT) gene was tested for association with age at disease onset, clinical signs, and anxiety-related traits of depression patients. A sample included 77 patients (mean age 61.2 ± 8.8 years) with late-onset depression (LOD, mean age at onset 56.58 ± 9.7 years) and 74 patients (mean age 31.0 ± 11.8 years) with early-onset depression (EOD, mean age at onset 23.9 ± 7.4 years). In genotype frequency distribution of two 5-HTT gene polymorphisms, the LOD and EOD groups did not differ from each other (² = 0.33, P = 0.85 for VNTR; ² = 3.33, P = 0.19 for HTTLPR) and from a control group (² = 0.34,P = 0.84 for VNTR; ² = 2.1, P= 0.35 for HTTLPR). In either group, patients differing in VNTR and HTTLPR genotypes did not differ in psychological traits and, in particular, in anxiety-related traits. In the case of the HTTLPR polymorphism, LOD patients with genotype sstended to display less severe neuroticism (t= 2.03, P = 0.0507) and scored significantly less on the Hamilton depression scale (t = 2.19, P = 0.039). Thus, the 5-HTT gene polymorphisms do not affect the risk of depression but is possibly associated with specific clinical signs of the disease, at least in elderly patients.