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At least 235 records · Page 13Linked to original sources
PubMed1998

Hirschsprung disease in MEN 2A: increased spectrum of RET exon 10 genotypes and strong genotype-phenotype correlation.

The RET proto-oncogene encodes a transmembrane receptor with tyrosine kinase activity. Germline mutations in RET are responsible for a number of inherited diseases. These include the dominantly inherited cancer syndromes multiple endocrine neoplasia types 2A and 2B (MEN 2A and MEN 2B) and familial medullary thyroid carcinoma (FMTC), as well as some cases of familial Hirschsprung disease (HSCR1). RET mutations in HSCR1 have been shown to cause a loss of RET function, while the cancer syndromes result in RET oncogenic activation. Occasionally MEN 2A or FMTC occurs in association with HSCR1, albeit with low penetrance. An initial report linked HSCR1 in MEN 2A solely to the C618R and C620R RET mutations. In this study we have analyzed 44 families with MEN 2A. HSCR1 co-segregated with MEN 2A in seven (16%) of the 44 families. The predisposing RET mutation in all seven families had been previously reported in MEN 2A or FMTC and occurred in exon 10 at codons 609, 618 or 620, resulting in C609Y, C618S, C620R or C620W substitution. MEN 2A families with RET exon 10 Cys mutations had a substantially greater risk of developing HSCR1 than those with the more common RET exon 11 Cys634 or exon 14 c804 mutations (P = 0.0005). These findings suggest that expression of HSCR1 in MEN 2A may be peculiar to RET exon 10 Cys mutations . However, HSCR1 in MEN 2A is not exclusive to C618R or C620R RET mutations and can occur with other exon 10 Cys amino acid substitutions. The strong correlation between disease phenotype and position of the MEN 2A RET mutation suggests that oncogenic activation of RET alone is insufficient to account for co-expression of the diseases.

Base Sequence↗
PubMed2001

Genotype-by-environment interaction with broiler genotypes differing in growth rate: 2. The effects of high ambient temperature on dwarf versus normal broilers.

High ambient temperatures (AT) reduce feed consumption (FC) and BW in broilers, thereby leading to lower efficiency and profitability of poultry meat production in hot climates. These negative effects have been found to be more pronounced in chicken lines with high BW. The effects of high AT were investigated in a broiler population segregating for the Dw gene and, thus, consisting of normal-sized and dwarf broilers, which differed markedly in BW but had the same genetic background. All chicks were reared under normal AT (constant 22 C) up to Day 44, when AT was gradually raised, over 24 h, to 32 C and then held constant to Day 49. The dwarf chicks had 23% lower BW and BW gain (WG) at all ages until Day 44. During the first 24 h at 32 C, FC of the dwarf broilers was reduced by 35% and their average WG was 7.6 g/d, whereas FC of their normal-sized counterparts was reduced by 46% and they lost BW (average WG: -42.1 g/d). Thereafter, however, the dwarf and normal broilers adapted similarly to the chronic heat stress, with FC and WG of both phenotypes averaging 72 and 35%, respectively, of the corresponding means at normal AT. The two phenotypes had similar body temperatures at normal AT, but following its increase, body temperature in the normal-sized broilers rose by 1.14 C, whereas in the dwarf ones it rose by only 0.47 C. This finding suggested better thermoregulation during acute heat stress, apparently due to the latter's smaller body size. Under chronic heat stress, however, FC and WG were similarly reduced in the dwarf and normal broilers. We concluded that the dwarf gene has no value with regards to broiler tolerance to chronic heat stress, either for production or as a model.

Adaptation, Physiological↗
PubMed2002

Genotype-by-environment interaction with broiler genotypes differing in growth rate. 4. Association between responses to heat stress and to cold-induced ascites.

Males and females, selected from a commercial line to represent its phenotypic variation for BW, were mated with similarly ranked mates to produce sire families representing a wide genetic variation in potential growth rate (GR). Following 5 wk of rearing at normal ambient temperatures, birds representing all sire families were exposed to cold (Days 37 to 47, Trial 1) or hot (Days 43 to 48, Trial 2) environments. Birds exhibiting ascites syndrome (AS) in the cold environment (Trial 1) were counted, and the incidence of AS (%AS) per family was calculated. Sire families' least-square means of BW at 37 d of age in Trial 1 and BW at 43 d of age in Trial 2 represented the families' potential GR (i.e., GR under normal conditions). A significant positive correlation was found between potential GR and %AS (r = 0.479, Trial 1), indicating that families with higher potential GR under normal conditions are more likely to suffer from AS under cold stress, compared to families with lower GR. Heat stress markedly reduced weight gain in all families (Trial 2); however, the genetic potential GR was negatively correlated with actual GR under heat stress (r = -0.411, Trial 2). Since offspring of the same sire families were exposed to the two stressful environmental conditions, correlations between sire families' means under the two environments could be calculated. A negative correlation was found between growth under heat stress (Trial 2) and %AS (Trial 1) (r = -0.439), indicating that families whose GR is more depressed under heat stress are more likely to suffer from AS under cold stress. These results suggest that the two stress responses may share similar control of the genetic variation in each trait and their negative genetic correlation with potential GR.

Animals↗
PubMed1975

Demonstration of the Rhesus haplotype CdE (r-y) in the genotype of 48 subjects from 8 families. Genotype CdE/CdE (r-yr-y) in 2 members of the same family.

Forty-eight individuals heterozygous for CdE (R-Y) haplotype were identified in the pedigrees of 8 kindreds containing 128 members. Two homozygotes CdE/CdE (r-yr-y) were found in a large inbred kindred. Our study among French blood donors of the Seine-Maritime region demonstrated that about one of two individuals possessing the Rhesus phenotype CcdEd (rh'rh') carried the CdE (r-y) haplotype.

Chromosomes↗
PubMed2002

Hepatitis D virus genotypes in intravenous drug users in taiwan: decreasing prevalence and lack of correlation with hepatitis B virus genotypes.

Of 368 hepatitis B virus (HBV)-infected intravenous drug users, 144 (39%) were positive for antibody to hepatitis D virus (anti-HDV). Anti-HDV-positive HBV carriers had a lower rate of positivity for HBV DNA than did anti-HDV-negative carriers (52 versus 73%, respectively). From 1986 to 1997, the average rate of decrease in the prevalence of HDV infection in this population was 4.7%/year.

Genotype↗
PubMed1994

Birth weight and non-insulin dependent diabetes: thrifty genotype, thrifty phenotype, or surviving small baby genotype?

OBJECTIVE: To determine the prevalence of diabetes in relation to birth weight in Pima Indians. DESIGN: Follow up study of infants born during 1940-72 who had undergone a glucose tolerance test at ages 20-39 years. SETTING: Gila River Indian community, Arizona. SUBJECTS: 1179 American Indians. MAIN OUTCOME MEASURE: Prevalence of non-insulin dependent diabetes mellitus (plasma glucose concentration > or = 11.1 mmol/l two hours after ingestion of carbohydrate). RESULTS: The prevalence was greatest in those with the lowest and highest birth weights. The age adjusted prevalences for birth weights < 2500 g, 2500-4499 g, and > or = 4500 g were 30%, 17%, and 32%, respectively. When age, sex, body mass index, maternal diabetes during pregnancy, and birth year were controlled for, subjects with birth weights < 2500 g had a higher rate than those with weights 2500-4499 g (odds ratio 3.81; 95% confidence interval 1.70 to 8.52). The risk for subsequent diabetes among higher birthweight infants (> or = 4500 g) was associated with maternal diabetes during pregnancy. Most diabetes, however, occurred in subjects with intermediate birth weights (2500-4500 g). CONCLUSIONS: The relation of the prevalence of diabetes to birth weight in the Pima Indians is U shaped and is related to parental diabetes. Low birth weight is associated with non-insulin dependent diabetes. Given the high mortality of low birthweight infants selective survival in infancy of those genetically predisposed to insulin resistance and diabetes provides an explanation for the observed relation between low birth weight and diabetes and the high prevalence of diabetes in many populations.

Adult↗
PubMed2003

Interaction between vitamin D receptor genotype and estrogen receptor alpha genotype influences vertebral fracture risk.

In view of the interactions of vitamin D and the estrogen endocrine system, we studied the combined influence of polymorphisms in the estrogen receptor (ER) alpha gene and the vitamin D receptor (VDR) gene on the susceptibility to osteoporotic vertebral fractures in 634 women aged 55 yr and older. Three VDR haplotypes (1, 2, and 3) of the BsmI, ApaI, and TaqI restriction fragment length polymorphisms and three ERalpha haplotypes (1, 2, and 3) of the PvuII and XbaI restriction fragment length polymorphisms were identified. We captured 131 nonvertebral and 85 vertebral fracture cases during a mean follow-up period of 7 yr. ERalpha haplotype 1 was dose-dependently associated with increased vertebral fracture risk (P < 0.001) corresponding to an odds ratio of 1.9 [95% confidence interval (CI), 0.9-4.1] per copy of the risk allele. VDR haplotype 1 was overrepresented in vertebral fracture cases. There was a significant interaction (P = 0.01) between ERalpha haplotype 1 and VDR haplotype 1 in determining vertebral fracture risk. The association of ERalpha haplotype 1 with vertebral fracture risk was only present in homozygous carriers of VDR haplotype 1. The risk of fracture was 2.5 (95% CI, 0.6-9.9) for heterozygous and 10.3 (95% CI, 2.7-40) for homozygous carriers of ERalpha haplotype 1. These associations were independent of bone mineral density. In conclusion, interaction between ERalpha and VDR gene polymorphisms leads to increased risk of osteoporotic vertebral fractures in women, largely independent of bone mineral density.

Aged↗
PubMed1983

Genotype x environmental interactions on reproductive traits of bovine females. III. Seasonal variation in postpartum reproduction as influenced by genotype, suckling and dietary regimen.

We examined the effect of season of calving (winter = October to March, summer = April to September) on postpartum reproductive traits by analyzing six data sets in which cows calved throughout the year. In two experiments, with suckled and nonsuckled cows, animals that calved in winter had longer (P less than .01) intervals from parturition to first estrus (IE) than those that calved in summer. Multiple regression analysis [model; IE = y + b1 (calving date) + b2 (calving date)2] indicated that the relationship between calving date and IE was less for nonsuckled cows than for suckled cows because there was heterogeneity of regression (P less than .005) between groups. A similar seasonal difference and calving date X suckling status interaction (P less than .10) was observed in a third experiment. Another experiment involved Holstein cows ranked for genetic ability for milk production. Cows with genetic ability for high milk production and calving in summer tended (P less than .12) to have shorter IE than winter-calving cows. Genetically low producing cows did not show this tendency and there was heterogeneity of regression (P less than .10) between groups. In two experiments cows were fed diets either low or high in energy and data were analyzed for three consecutive postpartum periods (PP1, PP2, PP3) beginning after first calving. In PP1 of one experiment, intervals to first ovulation, estrus and conception were longer in winter than in summer. The multiple regression equation between calving date and IE was significant (P less than .10) only for cows fed diets low in energy. There was no significant relationship between calving date and IE in PP2 or PP3. In the other experiment, there were not enough winter-calving cows to make seasonal comparisons in PP1 and season did not significantly influence IE in PP2 or PP3. We concluded that, in general, winter-calving cows appeared to take longer to regain reproductive competence after calving than summer-calving cows. Differences between seasons tended to be greater for suckled cows, cows with genetic ability for high milk production, primiparous cows and cows fed diets low in energy.

Animal Population Groups↗
PubMedDate not supplied

[Development of "Amplisens-HCV-genotype" reagent set for identification of hepatitis C virus genotypes 1a, 1b, 2a and 3a].

Multiple alignments of 119 nucleotide sequences of isolates of hepatitis C virus (HCV) were carried out to choose the type-specific primers for the 5'-ultra-core fragment of viral genome for the purpose of detecting the HCV 1a, 1b, 2a, and 3a subtypes. A PCR kit of reagents was designed for the amplification of cDNA HCV with selected type-specific primers and for making the electrophoresis in agarous gel. The kit comprises the positive control samples, i.e. HCV genome fragments, subtypes 1a, 1b, 2a and 3a, cloned in the plasmid vector. 440 cDNAHCV samples were simultaneously tested by using the worked out reagents' set and according to the method of Ohno et al. The results were found to be concordant in 336 cases, and were discordant in 4 samples. A sequencing of the PCR products and phylogenetic analysis showed that 1 sample belonged to subtype 4a, 2 samples belonged to subtypes 2k and 1 sample--to subtype 31.

DNA Primers↗