Antistaphylococcal action of lacto- and bifidobacteria and interleukn-2.

Antistaphylococcal action of Lactobacillus delbrueckii subsp. bulgaricus IMV B-7281, L. acidophilus LMV B-7279 and Bifidobacterium animalis VKB as well as interleukin-2 (IL-2) has been determined on the model of experimental staphylococcal infection in mice. It has been established that peroral administration of certain probiotic strains of lacto- and bifidobacteria or composition L. acidophilus LMV B-7279--L. delbrueckii subsp. bulgaricus IMV B-7281 with IL-2 to mice favored the reducing of terms of staphylococcus persistence in the kidneys of experimental mice. The studied schemes are promising for treatment of patients with surgical infection.

Genetic analysis of "metabolic syndrome" in the spontaneously hypertensive rat.

In the current review, we summarize results of genetic analyses of "metabolic syndrome" in the spontaneously hypertensive rat (SHR). These results include (1) linkage analyses in the HXB/BXH recombinant inbred (RI) strains derived from SHR and Brown Norway (BN-Lx) strains which revealed quantitative trait loci (QTL) for hemodynamic and metabolic traits on several chromosomes, (2) genetic isolation of these putative QTL within differential chromosome segments of SHR.BN congenic strains, (3) detailed mapping of these QTL within limited chromosome segments of SHR.BN congenic sublines, (4) sequencing of selected positional candidate genes which revealed important mutations in the Cd36 and Srebp1 SHR genes, (5) functional tests of these candidate genes in SHR transgenic lines, and (6) integrated gene expression profiling and linkage mapping in RI strains which will be used to identify co-regulated genes and to determine co-segregation of transcriptional profiles with physiological and pathophysiological phenotypes.

Genetic analysis of cardiovascular risk factor clustering in spontaneous hypertension.

The SHR is the most widely studied animal model of hypertension. In this strain, as in many humans with essential hypertension, increased blood pressure has been reported to cluster with other risk factors for cardiovascular disease, including insulin resistance and dyslipidemia. However, the genetic mechanisms that mediate this clustering of risk factors for cardiovascular disease or the hypertension "metabolic syndrome" remain poorly understood. In the current studies, we have demonstrated (1) that a gene or genes responsible for a whole spectrum of cardiovascular risk factors mapped to a limited segment of the centromeric region of rat chromosome 4, (2) that a spontaneous deletion in the gene for Cd36 that encodes a fatty acid transporter and is located directly at the peak of QTL linkages on chromosome 4 has been indirectly linked to the transmission of insulin resistance, defective fatty acid metabolism, and increased blood pressure, and (3) based on complementation analysis in two transgenic lines expressing wild-type Cd36 on the genetic background of the SHR strain harboring the deletion variant of Cd36, we have established that defective Cd36 can be a determinant of disordered fatty acid metabolism, glucose intolerance, and insulin resistance in spontaneous hypertension.

The influence of the genetic background on the interaction of retinoic acid with Lx mutation of the rat.

The teratogenic effect of RA was found to be significantly influenced both by genetic background and by the genotype of malformation mutation Lx. The presence of the Lx mutation and BN genetic background strongly increases the teratogenic effect of RA. On the contrary, the SHR genetic background was shown to protect foetuses from RA teratogenic affliction. Recombinant inbred strain BXH2 is endowed with a specific combination of BN and SHR genes, and following RA administration it exhibits the same embryolethal effect as the BN genetic background alone. Without the Lx mutation there was no effect of RA on hind limbs in SHR/SHR or SHR/BN progeny whilst there was a significantly higher occurence of oligodactyly in SHR/BN on forelimbs as compared to SHR/SHR (92.2% vs 11.5%). In +/Lx progeny, forelimbs were significantly more afflicted with oligodactyly in SHR/BN +/Lx in comparison with both SHR/SHR and SHR/BXH2 foetuses, which indicates that BN modifiers responsible for oligodactyly were not passed to the BXH2 strain. On the contrary, hind limbs of SHR/BXH2, +/Lx progeny exhibited the highest affliction (62% of polydactyly and/or oligodactyly). In homozygous Lx/Lx progeny, polydactyly prevailed in forelimbs of SHR/BXH2 following RA administration, whilst in BN/BN progeny oligodactyly was the most frequent affliction. On the hind limbs, the highest reduction of toe number after RA treatment was connected with BN modifiers. The polymorphism of normal morphogenetic factors was shown to be responsible not only for Lx. phenotypic manifestation, but also for the variability in the response to RA teratogenic action.

Mapping of quantitative trait loci for seminal vesicle mass and litter size to rat chromosome 8.

The spontaneously hypertensive rat (SHR) and the Brown Norway (BN) rat differ significantly in litter size (7.6 versus 4.5 pups). In the HXB and BXH sets of recombinant inbred (RI) strains derived from SHR and BN rats, heritability of litter size and of selected male reproductive parameters such as sperm production, sperm count, sperm morphology and motility, and the mass of the testis, epididymides, and seminal vesicles were estimated and a search was undertaken for quantitative trait loci (QTL) associated with these phenotypes. The mass of seminal vesicles was significantly associated with a QTL near the D8Cebr204S21 marker on chromosome 8 (LOD score = 4.1, P = 0.00001); this QTL was responsible for 46% of the genetic variability of the trait. The same gene marker on chromosome 8 also showed a suggestive association with the litter size. Litter size was significantly correlated with the mass of seminal vesicles (r = 0.58, P = 0.003). These findings indicate that the variability in litter size among RI strains may be due in part to differences in the mass of seminal vesicles and it is possible that both mass of seminal vesicles and litter size are determined by a pleiotropic effect of the same QTL on rat chromosome 8.

HXB/Ipcv and BXH/Cub recombinant inbred strains of the rat: strain distribution patterns of 632 alleles.

The HXB/Ipcv and BXH/Cub sets of recombinant inbred (RI) strains were derived from the spontaneously hypertensive rats (SHR/OlaIpcv) and normotensive Brown Norway (BN-Lx/Cub) rats. The RI strains were produced as a model system for genetic and correlation analysis of spontaneous hypertension and other risk factors of cardiovascular disease such as insulin resistance and dyslipidemia. The RI strains were phenotyped in multiple hemodynamic and metabolic traits. In the current study, we describe strain distribution patterns of 632 genetic markers.

Genetic analysis of the rat hypodactylous mutation.

Autosomal recessive rat hypodactylous mutation Hd leads in homozygous condition to reductive changes of the digital arch of all feet. There is a variable preaxial reduction of the number of fingers in both sexes. Moreover, homozygous males are sterile. Testes of homozygous Hd/Hd and +/Hd adult rats were examined in the light and electron microscopes. Spatial organization of stages of the spermatogenetic cycle was not confirmed in Hd/Hd testes comparing with +/Hd males. Significant decrease in the number of germ cells in seminiferous tubules of Hd/Hd testes was accompanied with loosening and vacuolization of the seminiferous epithelium. The assignment of the Hd locus to RNO10 excluded the suspected homology between rat and mouse Hd mutations. More precise mapping using microsatellite markers revealed close linkage of the Hd locus with the D1OMit8 marker defining Syb2 gene coding for synaptobrevin 2. A chromosomal segment of RNO10 carrying Hd and Syb genes is being incrossed onto BN and SHR inbred strains in order to examine the modifying influences of different genetic backgrounds.

Hematocrit and hemoglobin values are negatively correlated with insulin resistance in spontaneous hypertension.

It has been recently reported that increased hematocrit and hemoglobin values often accompany insulin resistance and compensatory hyperinsulinemia in humans. In the current study, we analyzed the relationship between hematocrit/hemoglobin on the one hand and insulin resistance, dyslipidemia, and hypertension on the other hand in HXB/BXH recombinant inbred (RI) strains derived from the spontaneously hypertensive rat (SHR) and the Brown Norway (BN) rat. The SHR progenitor strain had a significantly increased hematocrit values and it was also hypertensive and insulin-resistant when compared with the BN progenitor. The distribution of hematocrit and hemoglobin values among RI strains was continuous, suggesting a polygenic mode of inheritance. Analysis of RI strains revealed that hemoglobin was negatively correlated with insulin and insulin/glucose ratio, and that hematocrit was negatively correlated with insulin-stimulated glucose uptake in isolated adipocytes. There was no relationship between hematological parameters and blood pressure or lipid phenotypes in RI strains. The findings of the current study suggest that hematocrit and hemoglobin values might be added to the clustering variables related to the insulin resistance syndrome in the SHR strain.

The role of cell death in limb development of rats manifesting Lx allele on different genetic backgrounds.

Control of vertebrate digital pattern is a phylogenetically old mechanism. Animal strains with abnormal digital counts are a useful model system to study tissue, cell and molecular factors involved in limb patterning. The aim of this study was to investigate rat limb morphogenesis on gestation days 13 to 16 in normodactylous, polydactylous and oligodactylous fetuses where the deviation from the normal pentadactylous phenotype is caused by interaction of mutant Lx allele with different genetic backgrounds. General development was assessed by measurements of crown-rump length, and limb morphogenesis by hand and foot plate width. Skeletogenesis was studied histologically and by whole mount staining with Alcian Blue and Acridine Orange. Cell death was demonstrated by supravital staining and fluorescence microscopy and by standard histology on serial sections. No phenotypic differences among the groups were noted on day 13. On day 14, the oligodactylous hind limb buds were more spiky than normal and had well-developed preaxial necrotic site (foyer preaxial primaire) which was normally observed only on day 15. This area of programmed cell death was severely attenuated in polydactylous limb buds. Pollex triphalangy manifested as increased hand plate width from day 15. Also hind limb buds width differed by this stage between groups. No acceleration or retardation of skeletogenesis was observed in abnormal limbs. The data confirm the crucial role of spatial and temporal patterns of morphogenetic programmed cell death in control of digital pattern.

A genetic and correlation analysis of liver cholesterol concentration in rat recombinant inbred strains fed a high cholesterol diet.

Liver cholesterol concentration in rats fed a high cholesterol diet, is under genetic control which is supported by significant differences observed among inbred strains. For instance, the Brown Norway (BN-Lx/Cub) rat developed a twofold higher liver cholesterol concentration than the spontaneously hypertensive rat (SHR/Ola). In the current study, we used 30 recombinant inbred (RI) strains, derived from BN-Lx and SHR progenitors, to locate quantitative trait loci (QTL) that are responsible for differences in liver cholesterol concentrations between the BN-Lx and SHR strains. The heritability of liver cholesterol was estimated to be 0.55 and a significant association was detected between concentration of liver cholesterol and the D10Cebrp1016s2 marker on chromosome 10 (lod score = 3.3); this putative QTL was responsible for nearly 64% of additive genetic variability and thus represents a major genetic determinant of liver cholesterol concentration. Liver cholesterol concentrations significantly correlated with intermediate density lipoprotein (IDL) cholesterol levels.

Genotoxicity of purine acyclic nucleotide analogs.

The genotoxic and embryotoxic effects of phosphonomethoxyalkylpurines, a new group of antiviral agents, decrease in the following order: PMEG > PMEthioG > PMEDAP > PMEA > (R)-PMPDAP = (R)-PMPA. Results of the present study are fully consistent with the previously found efficacy of their diphosphates to inhibit the replicative DNA polymerases. The marked genotoxicity of PMEG and PMEthioG is comparable to that of mitomycin C, whereas the moderate genotoxicity of PMEA is comparable to that of AZT. (R)-PMPDAP and (R)-PMPA did not induce any structural aberrations of chromosomes under the experimental conditions.

Quantitative trait loci influencing cholesterol and phospholipid phenotypes map to chromosomes that contain genes regulating blood pressure in the spontaneously hypertensive rat.

The frequent coincidence of hypertension and dyslipidemia suggests that related genetic factors might underlie these common risk factors for cardiovascular disease. To investigate whether quantitative trait loci (QTLs) regulating lipid levels map to chromosomes known to contain genes regulating blood pressure, we used a genome scanning approach to map QTLs influencing cholesterol and phospholipid phenotypes in a large set of recombinant inbred strains and in congenic strains derived from the spontaneously hypertensive rat and normotensive Brown-Norway (BN.Lx) rat fed normal and high cholesterol diets. QTLs regulating lipid phenotypes were mapped by scanning the genome with 534 genetic markers. A significant relationship (P < 0.00006) was found between basal HDL2 cholesterol levels and the D19Mit2 marker on chromosome 19. Analysis of congenic strains of spontaneously hypertensive rat indicated that QTLs regulating postdietary lipid phenotypes exist also on chromosomes 8 and 20. Previous studies in the recombinant inbred and congenic strains have demonstrated the presence of blood pressure regulatory genes in corresponding segments of chromosomes 8, 19, and 20. These findings provide support for the hypothesis that blood pressure and certain lipid subfractions can be modulated by linked genes or perhaps even the same genes.

A genetic linkage map of the rat derived from recombinant inbred strains.

We have constructed a genetic linkage map in the rat by analyzing the strain distribution patterns of 500 genetic markers in a large set of recombinant inbred strains derived from the spontaneously hypertensive rat and the Brown-Norway rat (HXB and BXH recombinant inbred strains). 454 of the markers could be assigned to specific chromosomes, and the amount of genome covered by the mapped markers was estimated to be 1151 centimorgans. By including a variety of morphologic, biochemical, immunogenetic, and molecular markers, the current map integrates and extends existing linkage data and should facilitate rat gene mapping and genetic studies of hypertension and other complex phenotypes of interest in the HXB and BXH recombinant inbred strains.