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Biomedical subjects

L G Best

Publications and source records attributed to L G Best.

12 recordsLinked to original sources
PubMed2005

Linkage analysis of LDL cholesterol in American Indian populations: the Strong Heart Family Study.

Previous studies have demonstrated that low density lipoprotein cholesterol (LDL-C) concentration is influenced by both genes and environment. Although rare genetic variants associated with Mendelian causes of increased LDL-C are known, only one common genetic variant has been identified, the apolipoprotein E gene (APOE). In an attempt to localize quantitative trait loci (QTLs) influencing LDL-C, we conducted a genome-wide linkage scan of LDL-C in participants of the Strong Heart Family Study (SHFS). Nine hundred eighty men and women, age 18 years or older, in 32 extended families at three centers (in Arizona, Oklahoma, and North and South Dakota) were phenotyped for LDL-C concentration and other risk factors. Using a variance component approach and the program SOLAR, and after accounting for the effects of covariates, we detected a QTL influencing LDL-C on chromosome 19, nearest marker D19S888 at 19q13.41 [logarithm of odds (LOD) = 4.3] in the sample from the Dakotas. This region on chromosome 19 includes many possible candidate genes, including the APOE/C1/C4/C2 gene cluster. In follow-up association analyses, no significant evidence for an association was detected with the APOE*2 and APOE*4 alleles (P = 0.76 and P = 0.53, respectively). Suggestive evidence of linkage to LDL-C was detected on chromosomes 3q, 4q, 7p, 9q, 10p, 14q, and 17q. These linkage signals overlap positive findings for lipid-related traits and harbor plausible candidate genes for LDL-C.

Adolescent↗
PubMed2003

Evidence for joint action of genes on diabetes status and CVD risk factors in American Indians: the strong heart family study.

OBJECTIVES: Previous research among American Indians of the strong heart family study (SHFS) has demonstrated significant heritabilities for CVD risk factors and implicated diabetes as an important predictor of several of the phenotypes. Moreover, we recently demonstrated that genetic effects on CVD risk factors differed in diabetic and nondiabetic individuals. In this paper, we investigated whether a significant genetic influence on diabetes status could be identified, and whether there is evidence for joint action of genes on diabetes status and related CVD risk factors. METHODS AND RESULTS: Approximately 950 men and women, age 18 or older, in 32 extended families, were examined between 1997 and 1999. We estimated the effects of genes and environmental covariates on diabetes status using a threshold model and a maximum likelihood variance component approach. Diabetes status exhibited a residual heritability of 22% (h2=0.22). We also estimated the genetic and environmental correlations between diabetes susceptibility and eight risk factors for CVD. All eight CVD risk factors displayed significant genetic correlations with diabetes status (BMI (rhoG=0.55), fibrinogen (rhoG=0.40), HDL-C (rhoG=-0.37), ln triglycerides (rhoG=0.65), FAT (rhoG=0.38 ), PAI-1 (rhoG=0.67), SBP (rhoG=0.57), and WHR (rhoG=0.58)). Three of eight traits (HDL-C (rhoE=-0.32), ln triglycerides (rhoE=0.33), and fibrinogen (rhoE=0.20)) displayed significant environmental correlations with diabetes status. CONCLUSIONS: These findings suggest that in the context of a high prevalence of diabetes, still unidentified diabetes genes may play an important role in influencing variation in CVD risk factors.

Adolescent↗
PubMed2001

Hemochromatosis mutations C282Y and H63D in 'cis' phase.

Homozygosity for the C282Y mutation of the HFE gene is a highly significant risk factor for the development of hereditary hemochromatosis (HH) and the majority of patients with HH have this genotype. An Irish/Belgian female with an elevated serum ferritin level and a family history of hemochromatosis was tested for the presence of the C282Y and H63D mutations. Results of digested PCR products have shown the patient to be homozygous for C282Y mutation and heterozygous for H63D mutation. Sequencing confirmed these findings. Genotyping of the patient's offspring and husband has also indicated the inheritance of both C282Y and H63D in 'cis'. Implications of this finding are: 1) the compound heterozygous state is by far the most common, but not the universal, phase for individuals found to be heterozygous for the two mutations, C282Y and H63D; 2) the C282Y and H63D mutations in the 'cis' phase may account for some cases of questionable parentage.

Aged↗
PubMed1993

Computer-assisted DREZ microcoagulation: posttraumatic spinal deafferentation pain.

Our data demonstrate that approximately 23-29% of standard dorsal root entry zone (DREZ) microcoagulation procedures fail to relieve pain due to inadequate thermal lesions and that approximately 39% fail due to insufficient superior extent of lesions. The remaining failures are related to inadequate lesion placement, improper selection of patients, and, rarely, posttraumatic spinal deafferentation pain resulting from other non-DREZ mechanisms. Computer-assisted DREZ microcoagulation is a satisfactory procedure to treat intractable posttraumatic spinal deafferentation pain, brachial plexus avulsion pain, and lumbosacral nerve root avulsion pain. In all these conditions we have identified areas of abnormal focal hyperactivity in the DREZ area. Perhaps this procedure can be applied to other central pain conditions if, using this technique, abnormal focal hyperactivity is demonstrated to be present.

Catheter Ablation↗
PubMed1991

Familial posterior helical ear pits and Wiedemann-Beckwith syndrome.

Multiple cases of posterior helical ear pits (PHEP) with apparent autosomal dominant inheritance in a very large family are reported. There are at least 2 cases of Wiedemann-Beckwith syndrome (WBS) within this family. Three other instances of familial PHEP and/or WBS are presented. An individual with a somewhat atypical osteopetrosis and PHEP is described. The previous literature of PHEP and the association with WBS is reviewed.

Beckwith-Wiedemann Syndrome↗
PubMed1990

Chromosome abnormality in Kallmann syndrome.

We report on an individual with Kallman syndrome (KS) and a balanced de novo translocation (7;12)(q22,q24). None of 6 full sibs, 3 half-sibs, or parents have KS or this chromosome translocation. This is the only known report of KS with a chromosome abnormality. This may represent a spurious association or genetic heterogeneity vis-a-vis the reported linkage of KS to the steroid sulphatase gene on the X chromosome. The pathophysiology and genetics of KS are discussed.

Adult↗
PubMed1989

Familial duodenal atresia: a report of two families and review.

We report on 2 families with recurrence of uncomplicated duodenal atresia. The presence of consanguinity in one family, the frequent occurrence of consanguinity in parents of affected children previously reported, and the equal sex ratio suggest autosomal recessive inheritance.

Consanguinity↗
PubMed1981

Wiedemann-Beckwith syndrome: autosomal-dominant inheritance in a family.

We report four additional cases of Wiedemann-Beckwith syndrome (WBS): A mother, her brother, and two of her children (half-sibs). Theories of the genetic transmission of the WBS are reviewed. The trait in this family appears to be an autosomal-dominant with variable expressivity. A theory of delayed mutation of an unstable premutated gene is discussed and an interpretation and observations are offered which could alter slightly the expected pattern of inheritance. Eighty-eight other family members were screened for evidence of WBS and noteworthy findings are presented.

Adult↗
PubMedDate not supplied

"Double-muscle" trait in cattle: a possible model for Wiedemann-Beckwith syndrome.

The Wiedemann-Beckwith syndrome (WBS) was first described in 1963 as a group of anomalies involving primarily macrosomia, macroglossia, and omphalocele. Histologic studies of WBS show nesidioblastosis of the pancreas, adrenocortical cytomegaly, and persistent metanephric blastema of the kidney. Multiple lines of evidence indicate that the human 11p15.5 region is the locus of abnormality in WBS. Insulin-like growth factor II (IGF-2) frequently has been considered a candidate gene, and expression of IGF-2 is known to be significantly delayed in fetal skeletal muscle of double-muscle (DM) cattle. Other candidate genes recently have been proposed for WBS. A number of recessive alleles in the bovine myostatin gene (GDF8, mapped to bovine chromosome 2 and apparently orthologous to the human 2q22 region) have been shown to be responsible for DM. Recently the first human case of deficient GDF8 function has been reported, confirming the importance of this gene. Bovine IGF-2 has been sequenced and localized to chromosome 25. The primary purpose of this study was to compare and contrast histologic findings in DM and WBS. Immunohistochemical staining confirms changes similar to nesidioblastosis in the pancreas. Other dysplastic changes of a cystic nature are seen in the adrenal. The renal histology of DM fetuses did not appear significantly different than controls.

Adrenal Cortex↗