The transformation of irinotecan (CPT-11) to its active metabolite SN-38 by human liver microsomes. Differential hydrolysis for the lactone and carboxylate forms

Apolipoprotein E (apo E) is a component of all the classes of lipoproteins and can be distributed among apo B- (LpB) and non apo B-containing lipoproteins (Lp-non-B). Using a new electroimmunoassay kit, plasma apo E, apo E in Lp-non-B (apo E-Lp-non-B) and apo E in LpB (apo E-LpB) levels were measured in healthy control subjects (n=481) from 3 centers participating in the ECTIM study (Etude Cas-Témoins sur l'Infarctus du Myocarde), a population-based study on myocardial infarction. The distribution of apo E among lipoproteins was analyzed according to the apo E phenotype after adjustment for center, body mass index, tobacco use, alcohol consumption and triglycerides. Apo E was higher (average excess: + 0.32; P < 0.0001) and lower (average excess: -0.12; P < 0.0001) in subjects carrying the allele epsilon2 and the allele epsilon4 respectively, than in apo E3/3 subjects. These differences are the consequence of variations in apo E-Lp-non-B which clearly differed between the groups classified according to their apo E phenotype (P < 0.0001). The average excess of apo E Lp non-B compared to apo E3/3 subjects was + 0.43 (P < 0.0001) and -0.22 (P < 0.0001) for the epsilon2 and epsilon4 alleles respectively. Apo E-LpB was lower in subjects carrying the epsilon2 allele (P < 0.02) while the presence of the epsilon4 allele did not modify this parameter. The proportion of apo E within HDL was clearly higher and lower in subjects carrying apo E2 and apo E4 respectively than in apo E3/3 subjects. Although triglyceride levels were dependent on the apo E phenotype, the adjustment of the proportion of apo E in HDL for triglycerides hardly modified the results. For the first time, these results, using direct measurements on a large number of subjects, confirm the greater preference of apo E4 over apo E2 for LpB and vice versa for Lp-non-B. They also show a greater affinity of apo E2 for HDL compared to apo E3. This high affinity of apo E2 for HDL could be due to the formation of the apo E-A-II complex. These results indicate that apo E phenotype modulates the distribution of apo E among lipoproteins and suggest differences in lipoprotein metabolism between apo E2, apo E3 and apo E4.     

Improving critical thinking in nursing practice

In a Japanese population study of the D1S80 locus 24 alleles ranging from allele 16 to allele43 were analysed using PCR-RFLP. As two repeat units were found to contain the restriction cleavage site (CCAGG) for EcoRII, we digested the alleles with EcoRII, separated the digested fragments on polyacrylamide gels and stained with ethidium bromide. Of the 24 alleles 11 band patterns were identified and tentatively labeled E1 to E11. A total of 42 subtypes were detected in a population group of 111 unrelated individuals. All samples of allele 18 were of the E3 type, while about 60% of the allele24 samples were of the E4 type and about 40% were of the E8 type. The third most frequent allele (allele30) contained four types, E4, E8, E5 and E6. No deviations from Hardy-Weinberg equilibrium were observed. Since this method could differentiate those samples which had the same length but different sequences, it is quite useful for paternity testing and individual identification.     

Beta-2 adrenoceptor genetic variation is associated with genetic predisposition to essential hypertension: The Bergen Blood Pressure Study

We tested the hypothesis that genetic variation in the beta-2 adrenoceptor gene is associated with a genetic predisposition to hypertension. Offspring of two hypertensive parents were compared with offspring of two normotensive parents. The subjects were participants of the Bergen Blood Pressure Study, where couples were recruited in 1963 to 1964 and re-examined in 1990. We studied offspring of those couples in which both partners were either hypertensive or normotensive in both examinations. Twenty-three hypertensive and 22 normotensive families met the inclusion criteria. DNA samples from the first born of hypertensive family-history offspring and normotensive family-history offspring were analyzed. We used multiplex sequencing and specifically examined the promoter and the N-terminal portion of the beta-2 adrenoceptor gene. We found four genetic variants: at position -47, a C-->T substitution in the 5' leader cistron causing an Arg-->Cys exchange, at -20, a T-->C substitution, at +46 an A-->G substitution leading to an Arg16-->Gly exchange, and at +79, a C-->G substitution leading to a Gln27-->Glu exchange. The frequency of the Arg16 allele was significantly higher in the hypertensive family-history offspring compared to normotensive family-history offspring (58% vs. 28% P < 0.011). We constructed haplotypes for the four intragenic variants and found significant linkage dysequilibrium. In particular, the 5' leader cistron mutant with the wild type alleles at the other loci was significantly more frequent in offspring of hypertensive parents, compared to offspring of normotensive parents. We also performed a relative risk analysis comparing the Gly/Gly, Arg/Gly, and Arg/Arg alleles, which implicated the Arg-containing allele. Finally, we analyzed the effect of genotype on blood pressure in the offspring. We found a significant step-wise effect for all four polymorphisms examined. Our data suggest that the Arg variant of the Arg-->Gly exchange is associated with parental hypertension and higher blood pressure values in this northern European population.     

Beneficial effects of pentoxifylline treatment of experimental acute pancreatitis in rats

BACKGROUND: Apolipoprotein E (apo E) is a protein associated with plasma lipoproteins. Apo E polymorphism has been related to significant modifications of lipoprotein profile, as well as to the incidence of different pathologies including cardiovascular disease, Alzheimer's disease, and vascular dementia. Furthermore, it was proposed that apo E polymorphism might be involved in the aging selection process. OBJECTIVE: The purposes of the present study were the following: (1) to evaluate apo E polymorphism in 'successful' and 'unsuccessful' aging, defined as the absence or presence of disability and severe chronic diseases (mainly cardiovascular disease and dementia), respectively; (2) to evaluate the impact of apo E polymorphism on plasma lipids in very old individuals free of or affected by disability. METHODS: 253 Italian subjects including 100 free-living healthy octo- and nonagenarians, 62 disabled octo- and nonagenarians, and 91 healthy adult controls, all matched for origin were studied. Apo E phenotypes were determined by PhastSystem (Pharmacia). Lipoprotein parameters (total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, lipoprotein (a), and apoprotein A-I and B) were measured by standardized methods. ADL were evaluated by the Katz index. RESULTS: The frequency of sigma2, sigma3, and sigma4 alleles was 0.062, 0.887, and 0.051 respectively in the entire sample; no differences in alleles distribution were found between the three groups. When the subjects were divided according to the E type (E2 type: E2/E2 and E2/E3; E3 type: E3/E3; E4 type: E3/E4 and E4/E4), no differences in lipoprotein parameters emerged, but a trend toward higher total and LDL-cholesterol from the E2 to the E4 type was observed. The sigma4 allele had a raising effect, while sigma2 had a lowering effect on total cholesterol levels, but these effects were much less profound in the disabled octo- and nonagenarians. CONCLUSIONS: We conclude that (1) the frequency of the sigma4 allele is very low in this sample of subjects from central Italy; (2) no differences emerged in sigma4 distribution between healthy and disabled octo- and nonagenarians, and adult controls; the very low frequency of sigma4 allele might contribute to this finding; (3) our data do not support the hypothesis of a possible association between apo E polymorphism and longevity or disability in this population.     

Allele distribution at nine STR loci--D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317 and D7S820--in the Japanese population by multiplex PCR and capillary electrophoresis

Nine tetranucleotide short tandem repeat (STR) loci, D3S1358, vWA, FGA TH01, TPOX, CSF1PO, D5S818, D13S317 and D7S820, were analyzed in the Japanese population with a newly released kit for personal identification using multiplex PCR with fluorescent-labeled primers following capillary electrophoresis. The observed heterozygosities were 0.67, 0.77, 0.82, 0.61, 0.62, 0.73, 0.78, 0.81 and 0.74, respectively, and the combined discrimination power of the nineplex was 0.9999999991. None of the nine loci deviated from Hardy-Weinberg equilibrium expectations using the chi-square test, homozygosity test, likelihood ratio test and exact test after the grouping of the alleles. The nine STR loci allele frequencies were significantly different from those of other ethnic populations.     

Polymerase chain reaction analysis of allele frequency and loss at the Harvey ras locus in myeloid malignancies

The hypothesis that 'rare' variable number tandem repeat (VNTR) alleles of the Harvey ras (Ha-ras) locus are an inherited predisposing factor in myeloid malignancies has been evaluated. We describe an application of the polymerase chain reaction (PCR) which amplifies the VNTR region at the Ha-ras locus and offers a number of advantages over conventional Southern analysis. Ha-ras VNTR genotypes were assigned to 57 normal subjects, 46 patients with acute myeloid leukaemia (AML), 26 with myelodysplastic syndrome (MDS) and 49 with chronic granulocytic leukaemia (CGL). By comparison with previous reports we found significantly higher frequencies of rare alleles (20.2%) in our normal subjects of whom more than 35% had at least one 'rare' allele. The frequencies of rare alleles in the patient groups was not significantly different from the normal group (chi 2 = 0.54, p = 0.91). In studies of constitutional and leukaemic DNA from patients with AML, we found that allelic loss at the Ha-ras locus was not a common phenomenon. The improved resolution achievable with PCR compared with Southern analysis was demonstrated by the inability of Southern analysis to resolve six out of 34 PCR heterozygotes. We therefore suggest that previous studies showing linkage between rare Ha-ras alleles and susceptibility to malignancy should be reevaluated using our sensitive PCR technique.     

Evidence by allelic association-dependent methods for a type 1 diabetes polygene (IDDM6) on chromosome 18q21

Type 1 diabetes is a common polygenic disease. Fine mapping of polygenes by affected sibpair linkage analysis is not practical and allelic association or linkage disequilibrium mapping will have to be employed to attempt to detect founder chromosomes. Given prior evidence of linkage of the Jk-D18S64 region of chromosome 18q12-q21 to type 1 diabetes, we evaluated the 12 informative microsatellite markers in the region for linkage with disease by the transmission disequilibrium test (TDT) in a UK data set of type 1 diabetic families (n = 195). Increased transmission of allele 4 of marker D18S487 to affected children was detected (P = 0.02). Support for this was extended in a total of 1067 families from four different countries by isolating, and evaluating by the TDT, two novel microsatellites within 70 kb of D18S487. Evidence for linkage and association was P = 5 x 10(-5) and 3 x 10(-4), respectively. There was no evidence for increased transmission of associated alleles to nonaffected siblings. Analysis of an additional 390 families by the TDT did not extend the evidence further, and reduced support in the total 1457 families to P = 0.001 for linkage and P = 0.003 for association. However, evidence for linkage by affected sibpair allele sharing was strong (P = 3.2 x 10(-5)) in the second data set. Heterogeneity in TDT results between data sets was, in part, accounted for by the presence of more than one common disease-associated haplotype (allelic heterogeneity) which confounds the analysis of individual alleles by the TDT. Guidelines for strategies for the mapping of polygenes are suggested with the emphasis on collections of large numbers of families from multiple populations that should be as genetically homogeneous as possible.     

Expression of lactate dehydrogenase, myosin heavy chain and myogenic regulatory factor genes in rabbit embryonic muscle cell cultures

Polymorphisms of cytochrome P450 genes show pronounced interethnic variation and have not been previously studied in the South-Amerindian population, which probably has an Asian origin. Therefore, a similar distribution of allelic and haplotype frequencies of cytochrome P450 genes to Asian populations might be expected in South-Amerindians. We analysed the allelic frequencies and haplotype distribution for CYP2D6, CYP1A1 and CYP2E1 genes in the South-Amerindian population of Chile (Mapuche, n = 84) by Southern blot or polymerase chain reaction-restriction fragment length polymorphism. Similar allelic frequencies and haplotype distribution for the CYP2E1 gene between Mapuches and Asian populations were observed. Frequencies of the two major functional CYP2D6*1 and CYP2D6*2 alleles and the CYP2D6*5 null allele were similar to most populations world-wide. The alleles CYP2D6*3 and *9, absent in Asians, were not found in Mapuches. The CYP2D6*4 allelic group, uncommon in Asian populations, had a low frequency in Mapuches (0.036). However, the CYP2D6*10 allele (Ch1, Ch2 and J), highly frequent in Asians (0.33-0.50), had a very low frequency (0.018) in our study population. In addition, the presence of the common Chinese 44 kb XbaI fragment of CYP2D6 (0.19-0.31 in Asians) was not detected in South-Amerindians. Interestingly, high frequencies for the rare m2 and Val alleles of the CYP1A1 gene were found in Mapuches (0.821 and 0.91, respectively), and the rare Val/m2 haplotype was significantly higher in Mapuches (0.748) than in Asians (0.24) (P < 0.01). The frequency of this haplotype in Mapuches is the highest frequency reported to date. The population studied was in Hardy-Weinberg equilibrium for these polymorphisms. The major differences between Mapuches and Asians were for CYP2D6*10 and CYP1A1 allelic frequencies, as well as the absence of the common Chinese 44 kb XbaI fragment of CYP2D6. These differences might be interpreted as a consequence of genetic drifts caused by a founder effect in the settlement of South-Amerindians, or genetic selection caused by dietary or environmental factors.     

A novel microsatellite polymorphism in the human OB gene: a highly polymorphic marker for linkage analysis

The mouse ob gene and its human homologue OB have recently been cloned. The mutations in the ob gene are known to be associated with extreme obesity. The relationship between the human OB gene and disease, however, is largely unknown due to the lack of suitable markers within or adjacent to the OB gene. To obtain informative markers, we searched for simple tandem repeat polymorphisms in the genomic sequence of the human OB gene and identified a novel tetranucleotide repeat in the 3' flanking region. Fifteen alleles were detected in this marker with a heterozygosity of 0.85 and polymorphism information content of 0.83, indicating a highly informative nature of this marker. Two-point linkage mapping in two Centre Etude Polymorphisme Humaine (CEPH) reference families suggested that this marker is located in the interval between D7S514 and D7S530, the same interval where the OB gene is located (recombination fractions with D7S514 and D7S530 were 0.026 and 0.034, respectively). Although allele frequency distributions of this marker did not differ between 84 control subjects and 69 NIDDM patients, there was a tendency to higher body weight in control subjects with class I/class I genotype than in those without this genotype (68.8 +/- 11.1 vs 60.8 +/- 10.3 kg, p = 0.05). The highly polymorphic nature of this marker and its location in the OB gene makes this marker useful for linkage studies of the OB gene with a number of phenotypes, such as obesity, non-insulin-dependent diabetes mellitus, hypertension and the insulin resistance syndrome.     

Diurnal blood pressure patterns in normotensive and hypertensive children and adolescents

As abnormalities in diurnal ambulatory blood pressure (BP) have been associated with hypertensive target organ damage in adults, we investigated the diurnal systolic BP (SBP) and diastolic BP (DBP) patterns of 54 normotensive children, age 13.4 +/- 3.0 years, and 45 untreated borderline and mildly hypertensive children, age 14.4 +/- 2.6 years. Subjects wore the SpaceLabs 90207 ambulatory BP monitor for 24 h. BP was measured q 15 min from 08.00-21.00 h then q 30 min from 21.00-08.00 h. Nocturnal BP fall, the night-day ratio and cusum derived measures were calculated from time-weighted daytime and night-time SBP and DBP. The groups were compared using analysis of covariance with adjustment for age, race, gender and body mass index. The influence of age, gender and race on the diurnal BP profile was also examined. Nocturnal SBP fall was greater in hypertensive compared to normotensive subjects (17.1 +/- 6.7 vs 14.6 +/- 7.1 mm Hg; unadjusted mean +/- s.d., P = 0.022). Normotensive and hypertensive groups did not differ in nocturnal DBP fall or SBP or DBP night-day ratio. Race appeared to influence the diurnal BP pattern as black subjects had less nocturnal SBP fall (12.9 +/- 6.9 vs 17.1 +/- 6.5 mm Hg; P < 0.005) and a higher night-day SBP ratio (90.1 +/- 5.3 vs 86.7 +/- 4.6%; P < 0.005) than white subjects. In conclusion, hypertensive children and adolescents have a similar diurnal BP pattern as their normotensive counterparts, except that the entire BP profile is shifted upward with a greater absolute fall in SBP at night. Race also appears to influence the diurnal BP profile of normotensive and hypertensive children and adolescents.     

Clinical, haematological and molecular studies in patients with chromosome translocation t(7;11): a study of four Chinese patients in Taiwan

We examined the association between the polymorphism of the apolipoprotein E (apoE) and the ACE genes and the intima-media thickness (IMT) of the carotid and femoral arteries measured using ultrasonography. The values of IMT of each artery were significantly higher in NIDDM patients (n = 356) than in control subjects (n = 235). The E4 allele or the D allele did not affect clinical characteristics, including age, fasting plasma glucose, total cholesterol, HDL cholesterol, LDL cholesterol, or blood pressure, in NIDDM or control subjects. No difference in the carotid IMT value was noted among the apoE genotypes in control or diabetic subjects. The carotid IMT was significantly higher in diabetic patients with the DD genotype (1.200 +/- 0.586 mm) than in those with the II genotypes (0.990 +/- 0.364 mm). Neither the E4 allele nor the D allele affected the femoral IMT in control or diabetic subjects. Multiple regression analysis demonstrated that the carotid IMT of NIDDM patients was associated with age, the D allele, and LDL cholesterol but not with the E4 allele, whereas that of control subjects was associated with age, sex, systolic blood pressure, LDL cholesterol, and HDL cholesterol, inversely. These results suggested that the E4 allele was not associated with the carotid or femoral IMTs, but that the D allele was statistically associated with carotid IMT in NIDDM patients but not control subjects. However, since the association was weak (2.3% explanatory power), its biological significance remains to be determined.     

CYP2C19 genotype and phenotype determined by omeprazole in a Korean population

Omeprazole (20 mg orally) was given to 103 healthy Korean subjects and blood was taken 3 h after administration. The plasma concentration ratio of omeprazole and hydroxyomeprazole, used as an index of CYP2C19 activity, was bimodally distributed. Thirteen subjects (12.6%) were identified as poor metabolizers (PMs) with an omeprazole hydroxylation ratio of 6.95 or higher. Among the 206 CYP2C19 alleles, CYP2C19*2 and CYP2C19*3 were found in 43 alleles (21%) and 24 alleles (12%), respectively. Twelve subjects (12%) carried two defect alleles (*2/*2, *2/*3 or *3/*3), 43 subjects (42%) were heterozygous for a mutated (*2 or *3) and a wild type (*1) allele, and the remaining 48 subjects (47%) were homozygous for the wild type allele. The distributions of the metabolic ratio between these three genotype groups were significantly different (Kruskal-Wallis test: p < 0.0001). The genotypes of 19 additional Korean PMs has been identified in a previous mephenytoin study. From a total of 32 PMs, 31 were genotypically PMs by analysis of the CYP2C19*2 and *3 alleles and only one PM subject was found to be heterozygous for the *1 and *2 alleles. At present it cannot be judged whether this subject has a defective allele with a so-far unidentified mutation or a true wild type allele. We thus confirm a high incidence (12.6%) of PMs of omeprazole in Koreans and of the 32 Korean PMs 97% could be identified by the genotype analysis.     

Does the biocompatibility of the hemodialysis membrane influence the prognosis of acute renal insufficiency?

OBJECTIVE: This study was aimed at the use of old blood stains for investigating the distribution of three STR loci in Jingpo ethnic group. METHODS: DNA extraction from old blood stains (106 in number) and multiplex amplification of CSF1PO, TPOX and TH 01 were carried out. Using denaturing polyacrylamide gel electrophoresis and silver stain, the authors investigated the distribution of allele frequencies of CSF1PO, TPOX and TH01 loci in a Jingpo ethnic group in the southwestern part of Yunnan province. RESULTS: 7 alleles and 26 genotypes of CSF1PO locus,7 alleles and 19 genotypes of TPOX locus, and 6 alleles and 18 genotypes of TH01 locus were observed. CONCLUSION: The satisfactory results demonstrate that multiplex amplification of CSF1PO, TPOX and TH01 is sensitive and the old stain of a drop of blood is sufficient for such amplification.     

Association of posterior p-values of S.A.G.E. SIBPAL proportion-IBD and Haseman-Elston statistics for ACTHR112

A common practice among researchers performing linkage studies is the use of equal allele frequencies as input when reporting p-values from computer linkage programs such as S.A.G.E. SIBPAL. Our results, using 5,000 sets from a uniform-prior distribution of allele frequencies, showed that such input may be problematic. Further, we found that the S.A.G.E. SIBPAL test for proportion of alleles shared identical by descent among concordantly affected sib pairs showed a greater percentage of significant p-values with decreasing parental genotype information (Table III), while the S.A.G.E. SIBPAL Haseman-Elston test produced significant p-values comparatively less frequently (Table IV).     

Identification of human plasma kallikrein gene polymorphisms and evaluation of their role in end-stage renal disease

Kallikreins are serine proteases that release kinins from kininogens. Kinins, via their effects on cardiovascular and renal function, may be involved in the pathogenesis of hypertension and renal failure. Two groups of kallikreins exist, glandular or tissue kallikrein and plasma kallikrein. In this study, we examined the human plasma kallikrein gene KLK3 to determine whether it contributed to end-stage renal disease (ESRD) susceptibility. We identified two novel polymorphic sequences closely linked to the KLK3 gene, designated KLK3b and KLK3c (heterozygosities: 0.64 to 0.68 and 0.48 to 0.52, respectively). We mapped the KLK3 gene and the marker KLK3c to the long arm of human chromosome 4 between F11 and D4S426 using a radiation hybrid panel. The study population consisted of 142 sibling pairs concordant for ESRD from 121 African American families. The 142 sibling pairs were stratified into 78 pairs with hypertension- and chronic glomerulonephritis-associated ESRD and 64 with non-insulin-dependent diabetes mellitus-associated ESRD. Linkage analyses, using SIBPAL of SAGE, and exclusion analysis, using MAPMAKERS/SIBS, were performed. Linkage analysis of affected sibling pairs did not reveal any evidence of linkage of KLK3 to ESRD in all 142 sib-pairs or in the two stratified subsets. Exclusion analysis indicated that the KLK3 gene could be excluded from contributing to ESRD at a relative risk of 3 when the maximum log of the odds score of -2 was used as the criterion for exclusion. However, an association analysis using the relative predispositional effect technique showed that alleles 7 and 9 of KLK3b were consistently associated with ESRD. Alleles 7 and 9 were present in 11.2% and 10.8% of the 113 unrelated ESRD probands and in 6.6% and 6.6% of the 204 race-matched control subjects without renal disease (allele P=.0041 and .0016, respectively). Alleles 7 and 9 were also present in 13% and 10.4% of the proband's first siblings (allele P=.00014 and .0087, respectively). The association of KLK3b alleles with ESRD raises the possibility that polymorphisms in KLK3 may play a role in ESRD susceptibility. The lack of linkage might reflect our relatively small family set.     

Definition and distribution analysis of glycoprotein B gene alleles of human herpesvirus 7

As for other herpesviruses, glycoprotein B (gB) of human herpesvirus 7 (HHV-7) is believed to play a major role in virus infection and as a target of the host immunogenic response. Using nested PCR, we amplified the whole HHV-7 gB gene from 108 human peripheral blood mononuclear cell samples and studied its variability. By means of restriction fragment length polymorphism (RFLP) analysis, three distinct patterns, designated I, II, and III, were defined and detected at frequencies of 93, 5, and 2%, respectively. Determination of the nucleotide sequence allowed us to recognize five critical positions in the gB gene with six specific combinations of point changes at these positions. These combinations were gB alleles A, B, C, D, E, and F. Alleles D and E corresponded to RFLP patterns II and III, respectively, while the other four alleles corresponded to RFLP pattern I. Identical gB alleles were detected in serial samples as well as in paired samples of blood and saliva from the same individuals, except for one case. In contrast, the distribution of gB alleles differed according to the geographical origin of the human samples: C was the most frequent allele in both African and Caribbean samples, whereas F was the most frequent allele in European ones. Although none of the allele-specific nucleotide changes induced any modification at the protein level, the definition of gB alleles provided convenient viral markers for the study of both HHV-7 infections and human population genetics.     

CYP2D6 phenotype-genotype relationships in African-Americans and Caucasians in Los Angeles

CYP2D6 genotyping (CYP2D6*3, CYP2D6*4, CYP2D6*5, CYP2D6*13, CYP2D6*16 alleles and gene duplications) was previously performed on 1053 Caucasian and African-American lung cancer cases and control individuals and no significant difference in allele frequencies between cases and control individuals detected. We have carried out additional genotyping (CYP2D6*6, CYP2D6*7, CYP2D6*8, CYP2D6*9, CYP2D6*10, CYP2D6*17 alleles) and debrisoquine phenotyping on subgroups from this study to assess phenotype-genotype relationships. African-Americans showed significant differences from Caucasians with respect to frequency of defective CYP2D6 alleles, particularly CYP2D6*4 and CYP2D6*5. The CYP2D6*17 allele occurred at a frequency of 0.26 among 87 African-Americans and appeared to explain higher average metabolic ratios among African-Americans compared with Caucasians. CYP2D6*6, CYP2D6*8, CYP2D6*9 and CYP2D6*10 were rare in both ethnic groups but explained approximately 40% of higher than expected metabolic ratios among extensive metabolizers. Among individuals phenotyped with debrisoquine, 32 out of 359 were in the poor metabolizer range with 24 of these (75%) also showing two defective CYP2D6 alleles. Additional single strand conformational polymorphism analysis screening of samples showing large phenotype-genotype discrepancies resulted in the detection of three novel polymorphisms. If subjects taking potentially interfering drugs were excluded, this additional screening enabled the positive identification of 88% of phenotypic poor metabolizers by genotyping. This sensitivity was comparable with that of phenotyping, which identified 90% of those with two defective alleles as poor metabolizers.     

Association and linkage of the dopamine transporter gene and attention-deficit hyperactivity disorder in children: heterogeneity owing to diagnostic subtype and severity

Attention-deficit hyperactivity disorder (ADHD) affects approximately 3%-5% of children in the United States. In the current psychiatric nomenclature, ADHD comprises three subtypes: inattentive, hyperactive-impulsive, and combined. In this study, we used four analytic strategies to examine the association and linkage of the dopamine transporter gene (DAT1) and ADHD. Our sample included 122 children referred to psychiatric clinics for behavioral and learning problems that included but were not limited to ADHD, as well as their parents and siblings. Within-family analyses of linkage disequilibrium, using the transmission disequilibrium test (TDT), confirmed the 480-bp allele as the high-risk allele. In between-family association analyses, levels of hyperactive-impulsive symptoms but not inattentive symptoms were related to the number of DAT1 high-risk alleles. Siblings discordant for the number of DAT1 high-risk alleles differed markedly in their levels of both hyperactive-impulsive and inattentive symptoms, such that the sibling with the higher number of high-risk alleles had much higher symptom levels. Within-family analyses of linkage disequilibrium, using the TDT, suggested association and linkage of ADHD with DAT1 and that this relation was especially strong with the combined but not the inattentive subtype. The relation of DAT1 to ADHD increased monotonically, from low to medium to high levels of symptom severity. Our results replicate and extend previous findings of the association between the DAT1 gene and childhood ADHD. This represents one of the first replicated relations of a candidate gene and a psychiatric disorder in children.     

Urokinase-type plasminogen activator and plasminogen activator inhibitors (PAI-1 and PAI-2) in extracts of invasive cervical carcinoma and precursor lesions

BACKGROUND: HFE mutations are associated with hereditary haemochromatosis. However, a simple method capable of demonstrating the cis/trans arrangement of alleles is lacking, and linkage disequilibrium between HFE alleles and classic HLA loci is unknown. These are important issues as the pathogenic role of the mutations is not known. AIMS: To develop a simple method of genotyping HFE mutations suitable for clinical use in addition to large disease studies. PATIENTS: A total of 330 Caucasoid cadaveric organ donor controls were examined. Ten individuals previously HLA-H genotyped by polymerase chain reaction using restriction fragment length polymorphism (PCR-RFLP) were also examined to validate the method. METHODS: A simple polymerase chain reaction using sequence specific primers (PCR-SSP) capable of haplotyping the mutations was developed. HFE allele and haplotype frequencies and linkage disequilibrium with eight HLA class I and II loci were examined in the control population. RESULTS: 27% and 19.7% of patients were positive for the 63D and 282Y alleles, respectively. No chromosome carried both 63D and 282Y. Linkage disequilibrium between 282Y and HLA-A*03 was confirmed, but was not straightforward: some A*03-associated alleles (DRB1*15, DQB1*06), but not all (B*07, Cw*0702), were associated with 282Y. CONCLUSIONS: Linkage disequilibrium data suggest that an HLA-B*07 containing haplotype contains an element affording protection from haemochromatosis and may suggest the timing of the founder 282Y mutation.     

Weight reduction regresses left ventricular mass regardless of blood pressure level in obese subjects

The effects of weight reduction on left ventricular mass in obese normotensive and hypertensive subjects were investigated. Previous studies have shown that weight reduction in hypertensive (HT) obese patients is associated with decreased left ventricular mass (LVM) and decreased blood pressure (BP). This study was performed to examine whether weight reduction would also regress LVM in normotensive (NT) obese subjects and to clarify the mechanisms of these effects if they occurred. A weight-reduction program consisted of mild exercise and mild hypocaloric intake. M-mode echocardiography was performed to estimate the LVM. After the 12-week intervention, the mean reductions in body weight (BW) in the NT (n = 11) and HT (n = 11) groups were 4.9 kg (p < 0.005) and 4.6 kg (p < 0.0005), respectively. Systolic, diastolic, and mean BP were significantly reduced by 13, 9, and 11 mm Hg, respectively, in the HT group. By contrast, no significant changes in systolic, diastolic, or mean BP were observed in the NT group. LVM was significantly reduced from 176 +/- 26 gm to 159 +/- 26 gm (p < 0.05) in the HT group and from 167 +/- 33 gm to 145 +/- 34 gm (p < 0.02) in the NT group. These results suggest that weight reduction in obese subjects by mild exercise and mild hypocaloric intake can lead to a reduction in LVM, regardless of whether the subjects have normal or high blood pressure.