Putative association of peroxisome proliferator-activated receptor gamma co-activator 1beta (PPARGC1B) polymorphism with Type 2 diabetes mellitus

AIMS

Peroxisome proliferator-activated receptor gamma co-activator 1beta (PPARGC1B) may play an important role in obesity and Type 2 diabetes mellitus (T2DM). In an effort to identify genetic polymorphisms in potential candidate genes for T2DM, genetic associations of PPARGC1B were examined in a Korean T2DM study.

METHODS

We have sequenced the PPARGC1B, and examined its association with T2DM and diabetic phenotypes in a Korean T2DM study (775 T2DM patients and 316 control subjects) using the TaqMan method. Logistic and multiple regression models were employed to analyse the genetic contributions of polymorphisms. Nineteen polymorphisms were identified in PPARGC1B.

RESULTS

By logistic regression analysis controlling for age and sex as covariates, one non-synonymous single-nucleotide polymorphism (SNP; +102605C>A; Arg292Ser) in exon 5 showed marginal significant associations with the risk of T2DM. The allele frequency of the minor allele ['A (= Ser)' allele of +102605C>A] was lower among T2DM patients (frequency = 0.101) than among control subjects (frequency = 0.135) [P = 0.03, OR = 0.71 (95% CI: 0.51-0.94)]. Furthermore, serum triglyceride level was also associated with this non-synonymous SNP (+102605C>A; Arg292Ser) in exon 5 among controls (P = 0.03 in the dominant analysing model). Serum triglyceride levels [1.46 +/- 0.70 (log-transformed value; 0.12 +/- 0.18)] were lower in individuals who carry one or two copies of minor alleles than among others [1.60 +/- 0.85 (log-transformed value; 0.16 +/- 0.21)].

CONCLUSION

The present study provides, for the first time, information about genetic polymorphisms in PPARGC1B and putative associations of one non-synonymous SNP with the risk of T2DM and serum triglyceride (TG) levels in the Korean population, although this result was not significant after correction for multiple testing.

Poly(ADP-ribose) polymerase (PARP) polymorphisms associated with nephritis and arthritis in systemic lupus erythematosus

OBJECTIVE

The objective of this study was to confirm whether polymorphisms of the poly(ADP-ribose) polymerase gene (PARP) are associated with genetic susceptibility to systemic lupus erythematosus (SLE) and to investigate the possible association of nephritis and arthritis in SLE with PARP polymorphisms.

METHODS

Using direct DNA sequencing in 24 individuals, we identified 44 sequence variants within exons and their flanking regions, including the 1.5-kb promoter region of PARP. Six common polymorphic sites were selected for larger-scale genotyping (in 350 Korean SLE patients and 330 healthy controls), which identified six common haplotypes.

RESULTS

Although no statistically significant association with the risk of SLE was observed, we found that two single-nucleotide polymorphisms (SNPs -1963A --> G and +28077G --> A) were significantly associated with an increased risk of nephritis, and one non-synonymous variant [+40329T --> C(V762A)] was also significantly associated with an increased risk of arthritis, while the -1963A --> G SNP showed a protective effect on arthritis in Korean SLE patients.

CONCLUSION

Our results demonstrate that PARP polymorphisms are not associated with SLE susceptibility, but that -1963A --> G, +28077G --> A and +40329T --> C(V762A) are significantly associated with nephritis and arthritis in Korean SLE patients.

Association of PLXNA2 polymorphisms with vertebral fracture risk and bone mineral density in postmenopausal Korean population

INTRODUCTION

Plexin A2 (PLXNA2) is a receptor that recognizes secreted or membrane-bound semaphorin 3A, which is implicated in neural regulation of bone metabolism.

MATERIALS AND METHODS

In the present study, we identified 48 genetic polymorphisms in PLXNA2 by resequencing, and 10 single nucleotide polymorphisms (SNPs) were selected for further investigation into their potential involvement in osteoporosis in a postmenopausal population (n=560).

RESULTS

Two SNPs, +14G>A (Gln5Arg) and +183429C>T (Tyr1621Tyr), and Block1-ht2 were associated with risk of vertebral fracture (p=0.01-0.05), and three SNPs, +799G>A (Ala267Thr), +135391G>A, and +190531G>C, were associated with bone mineral density at various femur sites (p=0.003-0.03). Particularly, the minor allele of +14G>A was associated with a protective effect on vertebral fracture and higher lumbar bone mineral density, suggesting that +14G>A may be a useful marker for osteoporosis and its related fracture.

CONCLUSION

These results provide, for the first time, evidence supporting the association of PLXNA2 with osteoporosis in postmenopausal women.

Common promoter polymorphism in monocyte differentiation antigen CD14 is associated with serum triglyceride levels and body mass index in non-diabetic individuals

AIMS

Growing evidence supports the hypothesis that chronic low-grade inflammation related to innate immunity may play an important role in the pathophysiology of Type 2 diabetes mellitus (T2DM). The monocyte differentiation antigen CD14 gene (CD14) acts as the receptor for lipopolysaccharide (LPS) and augments monocyte/macrophage inflammatory responses.

METHODS

We have sequenced the gene, including all exons, exon/intron boundaries, and the -1.5 kb of the 5' flanking region. Two common loci (minor allele frequency > 0.05) were genotyped in 775 T2DM patients and 316 control subjects recruited in the Korean T2DM Study.

RESULTS

Eight polymorphisms, including four non-synonymous forms, were identified in CD14. No polymorphisms were found in association with T2DM. However, one common promoter SNP (-260T>C) was significantly associated with both the serum triglyceride level (TG) and body mass index (BMI) in non-diabetic control subjects. Individuals who carried the minor allele (C) had higher TG levels (1.65 +/- 0.81 vs. 1.46 +/- 0.80 mmol/l; P = 0.0007) and BMI (23.96 +/- 3.00 vs. 23.28 +/- 3.22 kg/m(2); P = 0.04) as compared with subjects carrying T/T genotypes.

CONCLUSION

Our data suggest that lipid metabolism and obesity, important pathophysiological elements of T2DM and the metabolic syndrome, are regulated by complex mechanisms that include the CD14 gene polymorphism-mediated genetic propensity to non-specific inflammatory responses.

Interleukin-10 gene polymorphisms are associated with the SLICC/ACR Damage Index in systemic lupus erythematosus

OBJECTIVE

Overproduction of interleukin-10 (IL-10) is a pivotal feature in the pathophysiology of systemic lupus erythematosus (SLE). We examined the IL10 genotype of Korean patients with SLE and normal controls to determine whether associations exist between the pattern of inherited IL10 genes and SLE susceptibility or the SLICC/ACR Damage Index (SDI).

METHODS

A total of 350 Korean SLE patients and 330 healthy subjects were enrolled. Direct DNA sequencing and primer extension procedures were employed. Logistic regression analyses were performed to examine the genetic association with SLE and SDI.

RESULTS

Eight sequence variants were identified by direct DNA sequencing in 24 Korean individuals. Five of the polymorphisms were selected for larger scale genotyping (n = 680) by considering their allele frequencies, haplotype-tagging status and linkage disequilibrium coefficients among polymorphisms. Haplotypes and allele distributions of the IL10 polymorphisms did not differ significantly between SLE patients and controls. Among identified SNPs, the rare C allele of IL10-592A-->C was significantly associated with the SDI among SLE patients in the following three alternative models: codominant (P = 0.007, odds ratio = 1.70), dominant (P = 0.02, odds ratio = 1.85) and recessive (P = 0.05, odds ratio = 2.25). Similarly, IL10+955T-->G and IL10-ht2 were significantly associated with the SDI in the codominant and dominant models.

CONCLUSION

IL10 polymorphisms are not associated with disease susceptibility in Korean patients with SLE. However, IL10-592A-->C, IL10+955T-->G and IL10-ht2 are significantly associated with the SDI, suggesting that IL10-592C, IL10+955G and IL10-ht2 accelerate the damage induced by SLE.

Association of a polymorphism in the gene encoding phosphoenolpyruvate carboxykinase 1 with high-density lipoprotein and triglyceride levels

AIMS/HYPOTHESIS

Phosphoenolpyruvate carboxykinase (PCK) is the key enzyme involved in the regulation of gluconeogenesis. The aim of this study was to identify genetic polymorphisms in potential candidate genes for type 2 diabetes by sequencing all exons in the PCK genes (PCK1 and PCK2), and examining the association with type 2 diabetes and diabetic phenotypes in a Korean population (775 type 2 diabetic patients and 316 normal control subjects).

MATERIALS AND METHODS

Twenty-two polymorphisms in PCK1 and PCK2 were identified in a Korean population (n=24) by direct DNA sequencing. The TaqMan genotyping method was applied for genotyping the remainder of the study population. Associations of PCK polymorphisms with the risk of type 2 diabetes and diabetic phenotypes were analysed using logistic and multiple regressions, adjusting for age, sex and BMI.

RESULTS

Although no significant associations between the genetic polymorphisms in PCK genes and the risk of type 2 diabetes were detected, in further haplotype analysis, one of the common haplotypes, PCK1 ht3, revealed susceptibility to type 2 diabetes (p=0.006). One 3' untranslated region (UTR) single nucleotide polymorphism (SNP) also showed an association with HDL levels among non-diabetic control subjects: individuals homozygous for the major allele (T/T) had the lowest HDL level (1.11+/-0.32 mmol/l), heterozygotes (T/C) had an intermediate level (1.27+/-0.37 mmol/l), and those homozygous for the minor allele (C/C) had the highest level (1.39+/-0.28 mmol/l) (p=0.000003). This 3' UTR SNP was also associated with triglyceride levels, with a lower triglyceride level observed among individuals who were homozygous for the minor allele (C/C) than among those who were not.

CONCLUSIONS/INTERPRETATION

The strong genetic association of HDL and triglyceride levels with variation/haplotype information identified in this study would be useful for further genetic epidemiological studies of this important gene.

Association between polymorphisms in the nuclear respiratory factor 1 gene and type 2 diabetes mellitus in the Korean population

AIMS/HYPOTHESIS

Dysfunction in mitochondrial oxidative phosphorylation plays a central role in insulin resistance and type 2 diabetes. Nuclear respiratory factor 1 (NRF1) is a transcription factor that acts on nuclear genes encoding respiratory subunits and components of the mitochondrial transcription and replication machinery. Thus, we investigated its genetic association with type 2 diabetes.

METHODS

The NRF1 gene was sequenced to identify polymorphisms in 24 Korean DNA samples and then common variants were genotyped in 766 patients with type 2 diabetes and 303 non-diabetic subjects.

RESULTS

Twelve single nucleotide polymorphisms and one insertion/deletion polymorphism were identified. Six common variants among them were genotyped in a larger study. Although three individual polymorphisms appeared to be associated with type 2 diabetes (g.-46350insdel A, g.+141G>T and g.+54529A>G), the effects were only marginal. However, a haplotype (H2) was associated with a decreased risk of type 2 diabetes and another haplotype (H4) was associated with an increased risk of type 2 diabetes (p values for the Haplo. Score test were 0.009 and 0.004, respectively).

CONCLUSIONS/INTERPRETATION

We demonstrated that two common haplotypes of NRF1 gene are associated with type 2 diabetes in the Korean population.

Association study of Toll-like receptor 9 gene polymorphism in Korean patients with systemic lupus erythematosus

Mammalian Toll-like receptors (TLR) play an important role in both adaptive immunity and innate immunity. Genetic variations within TLR genes are known to be associated with a variety of inflammatory and infectious diseases. TLR9 is potentially associated with autoimmune diseases, because it participates in the production of pro-inflammatory cytokines and the maturation of dendritic cells. We investigated the association of four TLR9 gene polymorphisms (-1486 T>C, -1237 C>T, +1174 A>G and +2848 G>A) with the susceptibility to systemic lupus erythematosus (SLE) and related phenotypes in 680 Korean people (350 SLE patients and 330 controls). TLR9 gene polymorphisms were not significantly associated with the susceptibility to SLE and related phenotypes.

Interleukin-10 haplotype associated with total serum IgE in atopic dermatitis patients

BACKGROUND

The genetic background of atopic dermatitis (AD) is not clearly understood. Interleukin (IL)-10 is a powerful Th-2 cell cytokine produced by lymphoid cells that exerts its function by inhibiting macrophage/monocyte and T-cell lymphocyte replication and secretion of inflammatory cytokines [IL-1, tumour necrosis factor-alpha (TNFA), IL-6, IL-8 and IL-12].

OBJECTIVE

In an effort to discover additional polymorphism(s) in genes whose variant(s) have been implicated in total immunoglobulin E (IgE) level in AD patients, we scrutinized the single nucleotide polymorphisms (SNPs) in the IL10 gene as a potent candidate for contributing to the level of IgE in serum.

METHODS

We recruited 334 AD patients and assayed their serum total IgE levels using the LIPA-200 system. Four SNPs in the IL10 gene were genotyped using the single-base extension (SBE) method. Logistic regression analyses were performed with single polymorphisms and haplotypes (ht) to determine their association with the level of serum total IgE.

RESULTS

Genetic association analysis of total serum IgE in AD patients revealed that one of the IL10 ht, IL10-ht2, was associated with decreased serum total IgE in gene dose-dependent manner (P = 0.02-0.001).

CONCLUSIONS

It was predicted that the inhibition of innate immunity by increased IL-10 production in IL10-ht2-bearing individuals might be associated with decreased total serum IgE levels among AD patients. The greater effects of IL10 ht on decreased total serum IgE levels suggest that the effect of IL-10 polymorphism might be the result of a combined genotype (ht) rather than single polymorphisms.

Genetic polymorphisms in peroxisome proliferator-activated receptor gamma are associated with Type 2 diabetes mellitus and obesity in the Korean population

AIMS

We examined whether the common polymorphisms of the peroxisome proliferator-activated receptor-gamma (PPARgamma) gene are associated with Type 2 diabetes or obesity in the Korean population.

METHODS

We genotyped two common PPARgamma polymorphisms (Pro12Ala and 161C > T) and examined their association with the clinical phenotypes found in 684 patients with Type 2 diabetes mellitus and 291 non-diabetic control subjects.

RESULTS

The 12Ala allele was less frequent in the Type 2 diabetic patients than in the non-diabetic control subjects (0.036 vs. 0.053, P = 0.024). The allele frequencies of the 161C > T polymorphism did not differ between the control and Type 2 diabetic group (0.158 vs. 0.173). In the non-diabetic controls, those with the T allele had lower BMI and fasting serum triglyceride (TG) concentrations than those with the C/C homozygote (22.7 +/- 2.9 vs. 23.8 +/- 3.2 kg/m2, P = 0.002; 1.45 +/- 0.81 vs. 1.65 +/- 0.83 mmol/l, P = 0.03, respectively). The 12Ala-161T haplotype was associated with a decreased risk for Type 2 diabetes (OR = 0.47, P = 0.009), whereas the 12Pro-161T haplotype was associated with lower BMI and lower fasting serum TG (22.5 +/- 2.8 vs. 23.7 +/- 3.2 kg/m2, P = 0.004; 1.41 +/- 0.87 vs. 1.64 +/- 0.79 mmol/l, P = 0.02, respectively).

CONCLUSIONS

The PPARgamma 12Ala allele was associated with a reduced risk of Type 2 diabetes, whereas the PPARgamma 161T allele was associated with lower BMI and fasting serum TG concentrations in the Korean subjects. The subjects with 12Ala-161T haplotypes had a reduced risk of Type 2 diabetes.

Peroxisome proliferator-activated receptor gamma coactivator 1 alpha promoter polymorphisms are associated with early-onset type 2 diabetes mellitus in the Korean population

AIMS/HYPOTHESIS

Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1alpha) is a transcriptional coactivator implicated in insulin release by beta cells and in insulin resistance. Therefore, genetic variation of PPARGC1A could be implicated in the onset of type 2 diabetes. In this study, we examined whether the PPARGC1A gene locus is associated with type 2 diabetes mellitus. We also investigated its association with clinical and metabolic parameters in healthy and diabetic subjects.

METHODS

After sequencing exons and their boundaries of the PPARGC1A gene, including the promoter region ( approximately 1.5 kb), we genotyped eight common single nucleotide polymorphisms (SNPs) in an association study comprising 762 unrelated patients with type 2 diabetes and 303 non-diabetic control patients. We divided the patients with type 2 diabetes into quartiles or three groups according to age at diagnosis of type 2 diabetes (early-onset: <40 years of age, average-onset: 40< or = <60 years, and late-onset: > or =60 years).

RESULTS

There was no strong association between SNPs or haplotypes of PPARGC1A and type 2 diabetes. However, the SNPs of g.-1789G>A and g.-1437C>T were associated with the age at diagnosis of type 2 diabetes (p=0.042 and p=0.032, respectively). In addition, the promoter SNPs of g.-1789G>A and g.-1437C>T and the haplotypes ht2 (-1789A and -1437T) were significantly associated with early-onset type 2 diabetes (p=0.002, p=0.001 and p=0.001, respectively).

CONCLUSIONS/INTERPRETATION

Our results suggest that PPARGC1A promoter polymorphisms are associated with age at diagnosis of type 2 diabetes and early-onset type 2 diabetes in the Korean population.

Association of interleukin 18 (IL18) polymorphisms with specific IgE levels to mite allergens among asthmatic patients

BACKGROUND

Allergy is regarded as a multifactorial condition. Its onset and severity are influenced by both genetic and environmental factors. Identification of genetic factors involved in asthma development and related phenotypes is a major task in understanding the genetic background of asthma. The possible involvement of IL18 polymorphisms in asthma was examined in a Korean asthma cohort.

METHODS

Direct sequencing was performed to discover single-nucleotide polymorphisms (SNPs) in the IL18 gene. Single-base extension (SBE) method was employed for genotyping. Genotypic influence of IL18 was analysed using logistic and multiple-regression models.

RESULTS

Although no polymorphisms in the IL18 gene showed significant association with the risk of asthma development, analyses of the association with specific serum IgE levels to Dermatophagoides farinae (D.f.) and D. pteronyssinus (D.p.) among asthmatic patients revealed significant associations with two completely linked SNPs, i.e. -148G>C and +13925A>C(Ser35Ser) (P = 0.01-0.11 for D.f. and P = 0.005-0.11 for D.p.). Both C allele of -148G>C and C allele of +13925A>C showed gene dose-dependent effects on the levels of specific IgE. The lowest IgE levels in homozygotes of minor alleles (1.13 and 1.22 of D.f.; 1.38 and 1.33 of D.p., respectively), intermediate IgE levels in heterozygotes (1.60 and 1.70 of D.f.; 1.84 and 1.92 of D.p., respectively), and the highest levels in homozygotes for major allele (1.93 and 1.93 of D.f.; 2.24 and 2.24 of D.p., respectively), were found.

CONCLUSION

The genetic relevance of IL18 to specific IgE might offer an important step in understanding the genetic background of allergic diseases.

Genetic association study of adiponectin polymorphisms with risk of Type 2 diabetes mellitus in Korean population

AIMS

To investigate any association between Type 2 diabetes mellitus and two single nucleotide polymorphisms (SNPs) in the adiponectin gene, T45G and G276T, in the Korean population.

METHODS

We genotyped 427 non-diabetic controls and 493 Type 2 diabetic patients for SNPs T45G and G276T of adiponectin gene, measured plasma adiponectin concentrations, and examined clinical parameters in Koreans.

RESULTS

There were no statistically significant differences in allele frequencies of SNPs 45 and 276 comparing control with Type 2 diabetic subjects (T frequency 68.3% vs. 71.6%, P=0.13 for SNP45, G frequency 72.2% vs. 68.9%, P=0.12 for SNP276). The genotype distributions of these SNPs had no association with the risk of Type 2 diabetes and metabolic parameters of insulin resistance. Plasma levels of adiponectin were not statistically different according to T45G and G276T either, in both control and Type 2 diabetic subjects.

CONCLUSION

The T45G and G276T of the adiponectin gene may not be an important determinant of Type 2 diabetes or insulin resistance in Korean subjects.

ADAM33 polymorphism: association with bronchial hyper-responsiveness in Korean asthmatics

BACKGROUND

A disintegrin and metalloprotease 33 (ADAM33) is expressed in the lung by fibroblasts and bronchial smooth muscle cells. Given its structure and cellular provenance, ADAM33 may be associated with airway remodelling and bronchial hyper-responsiveness. Single nucleotide polymorphisms (SNPs) and haplotypes of the ADAM33 gene have previously been associated with asthma susceptibility in the Caucasian population.

OBJECTIVE AND METHODS

To assess whether genetic variants of ADAM33 are related to asthma in a Korean population, we conducted an association study of the ADAM33 gene with asthma susceptibility, bronchial hyper-reactivity and serum IgE in Korean asthmatics (n=326) and normal controls (n=151). Five of the 14 polymorphisms originally reported to be associated with asthma development (S1 G>A, T1 T>C, V-1 C>A, V1 T>A, V4 C>G) were genotyped using single base extension and electrophoresis. Haplotypes and their frequencies were inferred using the algorithm implemented by the software Arlequin. Allele frequencies of each SNP and haplotypes were compared between the patients and the normal controls using logistic regression analysis.

RESULTS

There was no significant difference in the distribution of SNPs and the six haplotypes between asthmatics and normal controls. All single SNPs and six haplotypes in ADAM33 were also analysed for the association with level of PC(20) using general linear models. The distribution of the T1 T>C SNP and one haplotype (ht4: GCGG) showed significant association with log-transformed PC(20) methacholine level in the asthma patients (P=0.03 and 0.0007, respectively, using a co-dominant model).

CONCLUSION

Polymorphism of ADAM33 may contribute to development of BHR in asthma.

Multifactor-dimensionality reduction shows a two-locus interaction associated with Type 2 diabetes mellitus

AIMS/HYPOTHESIS

Type 2 diabetes mellitus is a complex genetic disease, which results from interactions between multiple genes and environmental factors without any single factor having strong independent effects. This study was done to identify gene to gene interactions which could be associated with the risk of Type 2 diabetes.

METHODS

We genotyped 23 different loci in the 15 candidate genes of Type 2 diabetes in 504 unrelated Type 2 diabetic patients and 133 non-diabetic control subjects. We analysed gene to gene interactions among 23 polymorphic loci using the multifactor-dimensionality reduction (MDR) method, which has been shown to be effective for detecting and characterising gene to gene interactions in case-control studies with relatively small samples.

RESULTS

The MDR analysis showed a significant gene to gene interaction between the Ala55Val polymorphism in the uncoupling protein 2 gene ( UCP2) and the 161C>T polymorphism in the exon 6 of peroxisome proliferator-activated receptor gamma ( PPARgamma) gene. This interaction showed the maximum consistency and minimum prediction error among all gene to gene interaction models evaluated. Moreover, the combination of the UCP2 55 Ala/Val heterozygote and the PPARgamma 161 C/C homozygote was associated with a reduced risk of Type 2 diabetes (odds ratio: 0.51, 95% CI: 0.34 to 0.77, p=0.0016).

CONCLUSIONS/INTERPRETATION

Using the MDR method, we showed a two-locus interaction between the UCP2 and PPARgamma genes among 23 loci in the candidate genes of Type 2 diabetes. The determination of such genotype combinations contributing to Type 2 diabetes mellitus could provide a new tool for identifying high-risk individuals.

Common genetic polymorphisms in the promoter of resistin gene are major determinants of plasma resistin concentrations in humans

AIMS/HYPOTHESIS

Resistin is thought to be an important link between obesity and insulin resistance. It has been suggested that genetic polymorphism in the promoter of resistin gene is a determinant of resistin mRNA expression and possibly associated with obesity and insulin resistance. In this study, we investigated the association between the genotype of resistin promoter and its plasma concentrations.

METHODS

We examined g.-537A>C and g.-420C>G polymorphisms in the resistin promoter and measured plasma resistin concentrations in Korean subjects with or without Type 2 diabetes. We also did haplotype-based promoter activity assays and the gel electrophoretic mobility shift assay.

RESULTS

The -420G and the -537A alleles, which were in linkage disequilibrium, were associated with higher plasma resistin concentrations. Individuals with haplotype A-G (-537A and -420G) had significantly higher plasma resistin concentrations than the others. Haplotype A-G had modestly increased promoter activity compared to the other haplotypes. Electrophoretic mobility shift assay showed that the -420G allele is specific for binding of nuclear proteins from adipocytes and monocytes. However, none of the two polymorphisms were associated with Type 2 diabetes or obesity in our study subjects.

CONCLUSIONS/INTERPRETATION

Polymorphisms in the promoter of resistin gene are major determinants of plasma resistin concentrations in humans.

Markers for mapping by admixture linkage disequilibrium in African American and Hispanic populations

Population linkage disequilibrium occurs as a consequence of mutation, selection, genetic drift, and population substructure produced by admixture of genetically distinct ethnic populations. African American and Hispanic ethnic groups have a history of significant gene flow among parent groups, which can be of value in affecting genome scans for disease-gene discovery in the case-control and transmission/disequilibrium test designs. Disease-gene discovery using mapping by admixture linkage disequilibrium (MALD) requires a map of polymorphic markers that differentiate between the founding populations, along with differences in disease-gene allele frequencies. We describe markers appropriate for MALD mapping by assessing allele frequencies of 744 short tandem repeats (STRs) in African Americans, Hispanics, European Americans, and Asians, by choosing STR markers that have large differences in composite delta, log-likelihood ratios, and/or I*(2) for MALD. Additional markers can be added to this MALD map by utilization of the rapidly growing single-nucleotide-polymorphism databases and the literature, to achieve a 3-10-cM scanning scale. The map will be useful for studies of diseases, including prostate and breast cancer, diabetes, hypertension, and end-stage renal disease, that have large differences in incidence between the founding populations of either Hispanics or African Americans.

[Host genetic epidemiology by single nucleotide polymorphism(SNP) analysis]

The completion of the whole human genome sequences is now a reality. Emphasis on the analysis of genetic variations on both an individual level and a population level is more important than ever. The identification and characterization of single nucleotide polymorphisms (SNPs) in target genes or candidate genes plays a crucial role in identification of disease genes and in expediting drug discovery/development. Identification of known SNPs can be easily accomplished by searching the ever-expanding public domain databases. However, discovery of new SNPs is best accomplished by sequencing a reasonable subset of the applicable population groups. Particular SNPs of interest will be the ones that affect coding changes and regulatory functions of genes. Once SNPs have been identified, the next step is to examine their frequency in disease models by accurate, cost-effective and high-throughput SNP genotyping methods. This presentation will cover the overview of principal techniques of SNP genotyping which have been developed so far. And also will be discussed the importance of well-defined disease model and error-free high-throughput SNP genotyping in candidate genes and genome-wide SNP screening in the near future.

Genetic restriction of HIV-1 pathogenesis to AIDS by promoter alleles of IL10

IL10 is a powerful TH-2 cell cytokine produced by lymphoid cells that limits HIV-1 replication in vivo, ostensibly by inhibiting macrophage/monocyte and T-cell lymphocyte replication and secretion of inflammatory cytokines (IL1, TNFalpha, IL6, IL8, and IL12). A genetic epidemiological scan of patients enrolled in AIDS cohorts for candidate gene-linked short tandem repeat polymorphisms revealed significant genotype associations for HIV-1 infection and progression to AIDS with markers adjacent to and tracking (by linkage disequilibrium) common single nucleotide polymorphic variants in the IL10 promoter region. Individuals carrying the IL10-5'-592A (IL10-5'A) promoter allele possibly were at increased risk for HIV-1 infection, and once infected they progressed to AIDS more rapidly than homozygotes for the alternative IL10-5'-592 C/C (IL10-+/+) genotype, particularly in the later stages of HIV-1 infection. An estimated 25-30% of long-term nonprogressors (who avoid clinical AIDS for 10 or more years after HIV-1 infection) can be attributed to their IL10-+/+ promoter genotype. Alternative IL10 promoter alleles are functionally distinct in relative IL10 production, in retention of an avian erythroblastosis virus transcription factor recognition sequence and in binding to specific putative nuclear transcription factors, suggesting a potential mechanism whereby IL10-5'A down-regulation of inhibitory IL10 facilitates HIV-1 replication in vivo, accelerating the onset of AIDS.

Polymorphisms of the human IFNG gene noncoding regions

Interferon gamma (IFN-gamma) is a multifunctional cytokine that is essential in the development of Th1 cells and in cellular responses to a variety of intracellular pathogens including human immunodeficiency virus (HIV-1). We screened genomic DNA samples from a predominately Caucasian male population of HIV-infected and healthy donors for polymorphisms in the human IFNG gene from -777 to +5608 by single-stranded conformational polymorphism. Surprisingly, the proximal promoter (-777 to transcription start) is invariant as no polymorphisms were found in over 100 samples tested. However, further screening revealed polymorphisms in other regions of the gene including a single base insertion in a poly-T tract in the first intron, three single base pair substitutions in the third intron, and another single base pair substitution in the 3' untranslated region (UTR). Electrophoretic mobility shift assay was used to investigate whether these variants have altered DNA-binding abilities, since intronic enhancer elements have been reported for the IFNG gene. Oligonucleotides constructed for two third intron variants showed no difference in DNA-binding abilities as compared with wild-type sequences. However, the 3'UTR variant showed the formation of unique DNA-binding complexes to radiolabeled oligonucleotide probes as compared with the wild-type sequence. The influence of a CA-repeat microsatellite on AIDS disease progression in HIV-1 seroconverters was tested by a Cox proportional hazards model. There is no evidence of an association between alleles and infection with HIV-1 or progression to AIDS. We report an invariant proximal human IFNG promoter and the existence of multiple intronic variants and a potentially functional 3'UTR polymorphism.

Dating the origin of the CCR5-Delta32 AIDS-resistance allele by the coalescence of haplotypes

The CCR5-Delta32 deletion obliterates the CCR5 chemokine and the human immunodeficiency virus (HIV)-1 coreceptor on lymphoid cells, leading to strong resistance against HIV-1 infection and AIDS. A genotype survey of 4,166 individuals revealed a cline of CCR5-Delta32 allele frequencies of 0%-14% across Eurasia, whereas the variant is absent among native African, American Indian, and East Asian ethnic groups. Haplotype analysis of 192 Caucasian chromosomes revealed strong linkage disequilibrium between CCR5 and two microsatellite loci. By use of coalescence theory to interpret modern haplotype genealogy, we estimate the origin of the CCR5-Delta32-containing ancestral haplotype to be approximately 700 years ago, with an estimated range of 275-1,875 years. The geographic cline of CCR5-Delta32 frequencies and its recent emergence are consistent with a historic strong selective event (e.g. , an epidemic of a pathogen that, like HIV-1, utilizes CCR5), driving its frequency upward in ancestral Caucasian populations.

Is it necessary to decorticate segmentally instrumented spines to achieve fusion?

STUDY DESIGN

The effects of spinal instrumentation and decortication on spinal arthrodesis rates--when performed independently and when used together--were studied in an experimental animal model.

MATERIALS AND METHODS

Fifty-two immature New Zealand white rabbits underwent six different spinal procedures. The animals were killed six weeks postoperatively and their spines were evaluated by gross examination, radiography, manual stress testing, and histologic means.

RESULTS

The addition of rigid instrumentation to autologous iliac grafting significantly improved fusion rates in animals that were not decorticated. However, when decortication was done, a statistically significant improvement could not be documented. The addition of decortication to autologous iliac grafting significantly improved fusion rates in noninstrumented spines, but in instrumented spines, a statistically significant improvement could not be demonstrated.

Velocity field of pulsatile flow in a porous tube

This paper describes velocity fields for fully developed periodic laminar flow in a rigid tube with a porous wall. We obtained an analytical solution of the flow by the linear approximation of the Navier-Stokes equation. Unlike the previous works with a constant seepage rate along the axis, we used a wall velocity which contained hydraulic permeation constant Lp. The axial velocity profile shows a local maximum velocity near the wall at a large Womersley number alpha. This suggests that concentration polarization in porous tubular membrane may be reduced at high frequencies if a membrane device is operated under pulsatile flow conditions. The magnitude of wall permeation velocity decreases linearly along the tube axis because the damping of the pressure difference between the inside and the outside of the tube is very small.

15-Hydroxyeicosatetraenoic acid dehydrogenase activity in microsomal fraction of mouse liver homogenate

The microsomal fraction of mouse liver homogenate showed NAD(P)-dependent dehydrogenase activity involved in the conversion of 15-hydroxyeicosatetraenoic acid to 15-ketoeicosatetraenoic acid, which was determined quantitatively by HPLC assay. This enzyme, tightly bound to membranes and relatively stable, possessed apparent values of Km of 8.3 microM and Vmax of 2.8 nmoles/mg.min in the oxidation of 15-HETE, and gave an optimum pH of 9.8. Additionally, the enzyme, not susceptible to the inhibition by indomethacin and showing a similar cosubstrate specificity between NAD and NADP, utilized other hydroxylated eicosanoids as substrates, based on HPLC analyses.