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V Kren

Publications and source records attributed to V Kren.

At least 109 records · Page 6Linked to original sources
PubMed1995

A genetic linkage map of the laboratory rat, Rattus norvegicus.

We report the construction of the first complete genetic linkage map of the laboratory rat. By testing 1171 simple sequence length polymorphisms (SSLPs), we have identified 432 markers that show polymorphisms between the SHR and BN rat strains and mapped them in a single (SHR x BN) F2 intercross. The loci define 21 large linkage groups corresponding to the 21 rat chromosomes, together with a pair of nearby markers on chromosome 9 that are not linked to the rest of the map. Because 99.5% of the markers fall into one of the 21 large linkage groups, the maps appear to cover the vast majority of the rat genome. The availability of the map should facilitate whole genome scans for genes underlying qualitative and quantitative traits relevant to mammalian physiology and pathobiology.

Animals↗
PubMed1995

Mapping and sequence analysis of the gene encoding the beta subunit of the epithelial sodium channel in experimental models of hypertension.

OBJECTIVE: To investigate whether mutations in the beta subunit of the epithelial sodium channel (Scnn1b) contribute to the pathogenesis of hypertension in the spontaneously hypertensive rat (SHR) and the Dahl salt-sensitive rat. DESIGN: We determined the chromosome location of the rat Scnn1b gene, tested for cosegregation with blood pressure, and sequenced near full-length Scnn1b complementary DNAs (cDNAs) from SHR and Dahl salt-sensitive rats. METHODS: Chromosome mapping was performed by somatic cell hybrid analysis and by linkage analysis in recombinant inbred strains derived from SHR and Brown-Norway rats. Cosegregation analysis was performed by testing for correlations between blood pressure and Scnn1b genotypes in these strains. DNA sequencing was performed on cDNAs prepared from reverse-transcribed messenger RNA derived from rat kidney. RESULTS: The Scnn1b gene was closely linked to the Sa gene on rat chromosome 1. Blood pressure correlated significantly with Scnn1b gene in the recombinant inbred strains. Analysis of near full-length Scnn1b cDNAs from SHR and Dahl rats failed to reveal any coding sequence mutations that could affect the predicted amino acid sequence of the Scnn1b protein. CONCLUSION: The Scnn1b gene maps near the Sa gene in a region of rat chromosome 1 involved in the inherited control of blood pressure. If disordered activity of the epithelial cell sodium channel contributes to the pathogenesis of hypertension in the SHR or Dahl models, it must stem from genetic lesions in sequences that regulate Scnn1b function or in sequences important to the structure or function of the other sodium channel subunits.

Animals↗
PubMed1995

Mapping of quantitative trait loci for blood pressure and cardiac mass in the rat by genome scanning of recombinant inbred strains.

In the HXB and BXH recombinant inbred strains derived from the spontaneously hypertensive rat and the normotensive Brown Norway rat, we determined the strain distribution patterns of 500 genetic markers to scan the rodent genome for quantitative trait loci regulating cardiac mass and blood pressure. The markers spanned approximately 1,139 cM of the genome and were tested for correlations with left ventricular mass adjusted for body weight, and with systolic, diastolic, and mean arterial pressures. The marker for the dopamine 1A receptor (Drd1a) on chromosome 17 showed the strongest correlation with left ventricular heart weight (P = .00038, r = -0.59) and the relationship to heart weight was independent of blood pressure. The markers showing the strongest correlations with systolic, diastolic, and mean arterial pressure were D19Mit7 on chromosome 19 (P = .0012, r = .55), D2N35 on chromosome 2 (P = .0008, r = .56), and Il6 on chromosome 4 (P = .0018, r = .53), respectively. These studies demonstrate that the HXB and BXH strains can be effectively used for genome scanning studies of complex traits and have revealed several chromosome regions that may be involved in the genetic control of blood pressure and cardiac mass in the rat.

Animals↗
PubMed1995

Chromosome 8 congenic strains: tools for genetic analysis of limb malformation, plasma triglycerides, and blood pressure in the rat.

Congenic strains with the polydactyly-luxate syndrome (PLS), the BN.lx and Lew.lx, were originally derived to study the expression and mode of inheritance of the lx mutant gene on rat chromosome 8. The BN.lx PLS congenic strain together with the spontaneously hypertensive SHR strain served as progenitors for the production of the HXB/BXH recombinant inbred (RI) strains. One of the RI strains, the BXH11, carrying PLS was used for the transfer of PLS determining lx allele onto the SHR strain genetic background. Using PCR analysis, differential segments of chromosome 8 of BN.lx and SHR.lx congenic strains were described and shown to carry also genes associated with blood pressure and plasma triglyceride regulation. Possible experimental exploitation of chromosome 8 congenic strains in these respects is thus discussed.

Animals↗
PubMed1994

Fast atom bombardment mass spectrometry of elymoclavine glycosides.

A series of nine naturally occurring and/or semi-synthetic elymoclavine mono- and oligoglycosides containing various sugar units was investigated by fast atom bombardment, high-resolution measurements and linked scans. The fragmentations of the [M+H]+ and [M+Na]+ ions are described and their different contributions to the structure elucidation are discussed.

Carbohydrate Sequence↗
PubMed1994

Biochemical genetics of methylglyoxal dehydrogenases in the laboratory rat (Rattus norvegicus).

A genetic locus controlling the electrophoretic mobility of a methylglyoxal dehydrogenase (EC 1.2.1.23) in the rat is described. The locus, designated Mgd1, is expressed in liver and kidney. Inbred rat strains have fixed either allele Mgd1a or allele Mgd1b. Codominant expression is observed in heterozygotes, providing evidence for a tetrameric enzyme structure. Backcross progenies showed the expected 1:1 segregation ratio, and there is evidence that Mgd1 is linked to Pep3 and Fh1 on chromosome 13. There is also evidence for two additional methylglyoxal dehydrogenases: Mgd2, present in liver and kidney, and Mgd3, present only in heart.

Aldehyde Oxidoreductases↗
PubMed1994

Use of recombinant inbred strains for evaluation of intermediate phenotypes in spontaneous hypertension.

1. The HXB/BXH recombinant inbred (RI) strains, derived from the spontaneously hypertensive rat (SHR) and the normotensive Brown Norway (BN.1x) rat, represent a very useful system for gene mapping and for genetic analysis of certain model diseases, such as spontaneous hypertension. 2. These RI strains were genotyped in multiple genetic polymorphisms and characterized in blood pressure and some intermediate phenotypes. 3. The analysis of RI strains has revealed that (i) a gene in the vicinity of the major histocompatibility complex (RT1) on chromosome 20, a kallikrein-related gene on chromosome 4 and the renin gene on chromosome 13 were significantly associated with blood pressure, and (ii) Na+ leak in red blood cells correlated with blood pressure whereas relative heart and kidney weights as well as platelet aggregation did not.

Animals↗
PubMed1994

Genes of stress in experimental hypertension.

1. A significant portion of blood pressure variance is modified by the environment. 2. The present report summarizes evidence that: (i) the environmental response is genetically determined; (ii) various stressors can evoke a differential response in hypertensive animals and constitute its intermediate phenotypes; (iii) the response to heat stress can be assigned to a single 'thermosensitivity' locus; (iv) candidate genes of susceptibility to environmental stresses are member(s) of the heat stress gene (HSP) gene families; (v) a restriction fragment length polymorphism of hsp70 and a single base mutation in the 3'-untranslated region of hsp27 are associated with hypertension in recombinant inbred strains. 3. In conclusion, HSP gene variants may be causative in susceptibility to hypertension.

Animals↗
PubMed1994

Evidence for teratogenicity of thalidomide using congenic and recombinant inbred rat strains.

Teratogenic properties of thalidomide were tested in two systems of laboratory rat strains carrying the mutant lx allele that determines the polydactyly-luxate syndrome. In agreement with our previous experiments, we have confirmed that the response of foetuses basically depends on their genotype. Foetuses of LEW/BN, +/+ genotype remained unaffected following 500 or 3 x 500 mg/kg thalidomide doses (43 and 56 foetuses, respectively). In LEW/BN, +/lx foetuses these doses elicited 24% and 87% hind feet polydactyly (14/59 and 53/61 foetuses, respectively), which was highly significant when compared with 84 vehiculum-treated and 235 untreated controls (P < 0.001). However, in 48 SHR/RI 2, lx/lx foetuses both pairs of limbs were affected in an opposite way after the 500 mg/kg thalidomide dose: hind feet oligodactyly (94/96 limbs) and increased front feet polydactyly occurred (in comparison with 70 controls, P < 0.001). The mutant lx allele as well as modifying genes are involved in the response to thalidomide.

Abnormalities, Drug-Induced↗
PubMed1994

A preliminary evaluation of drug biotransformation in hepatocytes of genetically defined rat strains.

This study was directed to use the genetically developed isoprenaline-sensitive (S), isoprenaline-resistant (R) and spontaneous hypertensive rats (SHR) as standard diseased animal models for in vitro liver function evaluation of drug biotransformation. Hepatic hexobarbital hydroxylase and glutathione transferase (GST) were evaluated by using hexobarbital and 1-chloro-2,4-dinitrobenzene (CDNB) as substrates, at concentrations of 0.21 mmol/l and 1 mmol/l, respectively. The assay was conducted by using isolated hepatocytes in suspension and hepatocytes in a bioreactor configuration. The data demonstrate that there are certain cellular pharmacokinetic differences in hexobarbital hydroxylase and GST activities in hepatocytes obtained from Wistar, SHR, R and S strains which can be better demonstrated, when using the model of perfused and immobilized hepatocytes.

Animals↗
PubMed1994

Cosegregation of the endothelin-3 locus with blood pressure and relative heart weight in inbred Dahl rats.

OBJECTIVE: To determine whether the endothelin-1 or endothelin-3 genes are genetically linked with blood pressure and relative heart weight in segregating rat populations, in the context of an elevated dietary sodium chloride intake. METHODS: Endothelin-1 and endothelin-3 genotypes of rats in segregating populations, derived from crosses of Dahl salt-sensitive (SS/Jr) rats with contrasting inbred strains, including Lewis rats, spontaneously hypertensive rats and Dahl salt-resistant (SR/Jr) rats, were determined using restriction fragment length polymorphisms. Segregating populations were fed a high (8%)-sodium chloride diet. Linkage of genotype with blood pressure or relative heart weight was determined by analysis of variance. Chromosomal location of the rat endothelin-3 gene was determined by genotyping a panel of recombinant inbred strains. RESULTS: Two alleles for the endothelin-1 gene and three alleles for the endothelin-3 gene were identified. The endothelin-1 locus did not cosegregate with blood pressure or relative heart weight. The endothelin-3 locus cosegregated with blood pressure and relative heart weight in an SS/Jr x F1 (SS/Jr x SR/Jr) population, but not in populations containing a higher percentage of genes from the SR/Jr strain. The endothelin-3 and seminal vesicle protein-1 loci were linked and located on rat chromosome 3. CONCLUSION: The endothelin-3 gene is, or is linked to, a locus on chromosome 3 that regulates blood pressure and relative heart weight in inbred Dahl rats, and these effects were strongly dependent on the genetic background.

Animals↗
PubMed1993

Renal renin activity is associated with alterations of the renin gene in recombinant inbred rat strains.

1. A structural alteration within the first intron of the renin gene in spontaneously hypertensive rats was demonstrated to co-segregate with blood pressure in some sets of F2 hybrids or recombinant inbred strains. There is no evidence as to whether restriction fragment length polymorphism of the renin gene is associated with any of the changes in the renin tissue level. For this reason we have determined renal renin activity in spontaneously hypertensive, Wistar-Kyoto and Brown Norway rats as well as in 22 recombinant inbred strains derived from F2 hybrids of spontaneously hypertensive and Brown Norway rats. 2. At the age of 4 months significantly lower renal renin activity was observed in spontaneously hypertensive rats than in both normotensive rat strains, Wistar-Kyoto and Brown Norway. The presence of the spontaneously hypertensive rat allele in recombinant inbred strains was associated with a substantially lower renal renin activity as compared with recombinant inbred strains bearing the Brown Norway rat allele. There was no relationship between renal renin activity and the polymorphism in either the angiotensinogen gene or the angiotensin-converting enzyme gene. 3. There was a borderline correlation between blood pressure and renal renin activity in recombinant inbred strains. Nevertheless, additional comparisons within recombinant inbred strains bearing the spontaneously hypertensive rat allele of the renin gene failed to reveal any significant relationship between blood pressure level and renal renin activity. 4. Our data suggest that the restriction fragment length polymorphism marking the renin gene of the spontaneously hypertensive rat is accompanied by an alteration in the renin-angiotensin system at the renal level.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensinogen↗