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At least 199 records · Page 11Linked to original sources
PubMed1996

Effect of genetic background on the contribution of New Zealand black loci to autoimmune lupus nephritis.

Autoimmune diseases such as systemic lupus erythematosus are complex genetic traits with contributions from major histocompatibility complex (MHC) genes and multiple unknown non-MHC genes. Studies of animal models of lupus have provided important insight into the immunopathogenesis of disease, and genetic analyses of these models overcome certain obstacles encountered when studying human patients. Genome-wide scans of different genetic crosses have been used to map several disease-linked loci in New Zealand hybrid mice. Although some consensus exists among studies mapping the New Zealand Black (NZB) and New Zealand White (NZW) loci that contribute to lupus-like disease, considerable variability is also apparent. A variable in these studies is the genetic background of the non-autoimmune strain, which could influence genetic contributions from the affected strain. A direct examination of this question was undertaken in the present study by mapping NZB nephritis-linked loci in backcrosses involving different non-autoimmune backgrounds. In a backcross with MHC-congenic C57BL/6J mice, H2z appeared to be the strongest genetic determinant of severe lupus nephritis, whereas in a backcross with congenic BALB/cJ mice, H2z showed no influence on disease expression. NZB loci on chromosomes 1, 4, 11, and 14 appeared to segregate with disease in the BALB/cJ cross, but only the influence of the chromosome 1 locus spanned both crosses and showed linkage with disease when all mice were considered. Thus, the results indicate that contributions from disease-susceptibility loci, including MHC, may vary markedly depending on the non-autoimmune strain used in a backcross analysis. These studies provide insight into variables that affect genetic heterogeneity and add an important dimension of complexity for linkage analyses of human autoimmune disease.

Aging↗
PubMed1980

Hypomyelinated mutant mice: description of jpmsd and comparison with jp and qk on their present genetic backgrounds.

Hypomyelinated mutant mice are valuable natural animal systems for analysis of CNS myelin development, chemistry and diseases. One mutant, jpmsd, has never received thorough morphological description. We here describe the detailed morphology of jpmsd, compare it with well-studied jp and qk on their present genetic backgrounds, and discuss the genetic histories of all 3 mutants. Region for region, jpmsd has twice as much myelin as jp, but 1/2--1/5 as much as qk. Both jp and jpmsd have scarce oligodendrocytes, rare nodes of Ranvier, clustering of myelin segments, abnormal lipid-filled cells, frequent degenerating cells, and rare distorted myelin profiles. In contrast, qk has abnormally numerous oligodendrocytes, frequent nodes of Ranvier, no obvious myelin clustering, no lipid-filled cells, rare degenerating cells, and frequent abnormal or distorted myelin profiles. jp and jpmsd are quantitatively different, but qualitatively similar. Since its origin, the jpmsd disease has inadvertently been ameliorated by transferring the mutation to a different background. Persistent differences in the remainder of the genome might account for all remaining apparent differences between jp and jpmsd. In contrast, qk is totally dissimilar in morphology and presumably in pathophysiology.

Animals↗
PubMed2002

[Genetic background of Japanese thrombophilia].

Coagulation Factor V Leiden has not been detected in Japanese patients suffering from thromboses. The genetic background of Japanese thrombotic patients has never been systematically examined. We have performed a systematic investigation to ascertain genetic risk factors for thromboses in the Japanese population. According to our results, we recommend here useful gene analyses for Japanese thrombophilia.

Asian People↗
PubMed1996

[Effect of genetic background on mutation frequency of insertional alleles of the lozenge in Drosophila melanogaster].

We studied the effect of genetic background on mutation frequency of an unstable lz75V allele of the lozenge gene (lz; 1-27.7) isolated from natural populations of Drosophila melanogaster and its mutant derivatives lzB abd lzsl. Genetic composition of the X chromosome containing unstable alleles (X75V chromosome) was shown to affect their mutability. The region of the chromosome proximal to lozenge contains factors required for high mutability of lz75V and lzB. Substitution of a distal part of the X chromosome from a laboratory strain for a homologous part of the X75V chromosome also resulted in stabilizing lz75V, but caused an increase in mutation frequency of lzB. Association between instability of lz75V and the presence of P element with the locus was revealed by in situ hybridization. Studying effects of regulatory elements from a pi 2 P strain showed that the P cytotype is associated with a twofold to threefold decrease in mutation frequency of lzB and lzsl, but P-M hybrid dysgenesis is associated with its slight increase. Regulation of instability of the lozenge gene within the X75V chromosome was assumed to involve three levels: (1) character and topography of a mobile element inserted into the locus, (2) regulatory factors of other X-chromosomal regions, and (3) cytoplasmic factors. The results obtained are discussed in terms of regulation of transposition of mobile genetic elements.

Alleles↗
PubMed1997

A search for environmental and genetic background for neural tube defects: twenty-five years of experience.

The present paper illustrates the author's 25-year experience in a step by step approach to the definition of environmental and genetic background of neural tube defects. Based on the birth defects registry, a complete ascertainment of all deliveries was performed in Southern Poland during two periods: 1970-1972, and 1979-1981. The birth prevalence of neural tube defects (NTD), as well as other CNS malformations was determined. The empiric recurrence risk was calculated as 3.2% +/- 1.6. Based on this figure, the relative risk (RR = 37.6 p < 0.001) and heritability (h2 = 74.7 +/- 6.7) were estimated. Our own modification of Morton's complex segregation analysis was applied. Three Mendelian (dominant, additive and recessive) and one multifactorial model were tested. The results did not provide a clear cut discrimination between different models; however the lowest x2 value was obtained for additive inheritance with 61% of penetrance and the frequency of sporadic cases equaled 55%. A search for genetic markers did not support the hypothesis that HLA-A,B,C loci are equivalents of T/t like locus in mice. The results of the study on transcobalamine levels in amniotic fluid may suggests that different transcobalamine metabolism reflects phenotypic expression of genetic susceptibility to NTD development. Current research status and future perspectives on genetic and environmental background of NTD are also presented.

Abnormalities, Drug-Induced↗
PubMed1995

The relative impact of bacterial virulence and host genetic background on cytokine expression during Mycobacterium avium infection of mice.

Resistance to Mycobacterium avium depends on both genetically encoded macrophage functions and acquired T-cell immunity. Cytokines may play a role in either type of resistance. We studied the expression of interleukin-2 (IL-2), IL-4 and interferon-gamma (IFN-gamma) in naturally susceptible BALB/c (Bcgs) and naturally resistant C.D2 (Bcgr) congenic mice infected with two strains of M. avium (one highly virulent and another of low virulence). We observed that cytokine expression patterns correlated better with the virulence of the micro-organism than with the genetic background of the host. The control of the infection by the low virulence strain in either mouse strain was associated with an increased expression of IFN-gamma and IL-2. Only Bcgs mice infected with a virulent strain of M. avium were unable to restrict bacterial growth. An increased expression of IL-4, early during infection, was detected in the course of the latter infection but played no role in determining the susceptibility to infection. Neutralization of IFN-gamma or IL-2 with specific monoclonal antibodies led to an exacerbation of the infection in Bcgr mice by the two strains of M. avium and in Bcgs mice infected with the low virulence strain of M. avium.

Animals↗
PubMed2002

A quick and simple method for detecting subjects with abnormal genetic background in case-control samples.

It is important that case-control samples be drawn from a genetically homogeneous population in order to avoid artefactual false positive results and to enhance power to detect disease mutations and markers in linkage disequilibrium with them. Tests which simply compare overall marker allele frequencies between cases and controls will fail to identify a relatively small number of subjects drawn from a different genetic background who could usefully be discarded from the sample. Such subjects can be identified using multilocus tests, but previously described tests have been unnecessarily complex and cumbersome for this simple application. We describe a straightforward test, implemented in the CHECKHET program, which uses a measure of genetic difference and permutation procedures to rapidly identify such subjects using genotypes from multiple unlinked markers. It seems to perform reasonably well on simulated data, and with real data appears to identify two abnormal subjects within a case-control sample. We recommend that such tests be routinely applied to case-control samples once sufficient numbers of markers have been genotyped within them.

Case-Control Studies↗
PubMed1996

[Clinical characteristics and genetic background of secondary amyloidosis associated with rheumatoid arthritis in Japanese].

In order to examine the clinical characteristics and genetic background of secondary amyloidosis associated with rheumatoid arthritis, we analyzed clinical features and HLA typing of 85 patients in a multicenter study. Eighty-five patients with secondary amyloidosis associated RA were studied. The diagnosis of secondary amyloidosis were made on histological findings by biopsy or autopsy. The most common biopsy site was gastrointestinal tract (79.5%). Clinical symptom and the frequency at the time of diagnosis were; diarrhea (35 cases), abdominal pain (22 cases) and vomiting and nausea (16 cases). Abnormalities and the frequency in a laboratory test included proteinuria (49 cases), increased serum creatinine (32 cases), anemia (30 cases) and hematuria (15 cases). Twenty-eight patients were dead and 57 patients were alive at the time of the study. The average duration between diagnosis of amyloidosis and death was 19.4 +/- 18.5 (SD) months among the dead patients. The average duration after diagnosis of amyloidosis was 24.2 +/- 19.5 (SD) months in surviving patients. The causes of death were renal failure complicated with heart failure (6 patients), heart failure alone (3 patients) and renal failure alone (2 patients). Fifty-nine patients in the control group who were negative to amyloid deposition on biopsies at more than one site in the gastrointestinal tract, were clinically compared with patients in the amyloidosis group. No difference were noted in the age of RA occurrence and the stage between the two groups. As to the class, however, the number of patients with severe functional disorder (class 3 or severe) was larger in the amyloidosis group. There were no significant difference between the two groups in Lansbury's activity index. On hematology, biochemistry and urinalysis, the incidences of increased white blood cell count, anemia, increased platelet count, increased serum creatinine, hypoproteinemia, hypoalbuminemia, increased IgA, and increased urine and blood BMG were statistically significantly higher in the amyloidosis group than in the control group. HLA-A, -B, -C, and DR-locus antigens were compared in the 53 patients in the amyloidosis group and in the 59 subjects in the control group. There were no significant differences in frequency of HLA-A, and -B antigens between two groups. Frequency of CW7 antigen was significantly decreased in the amyloidosis group (13.2%) than in the control group (39.0%). Frequency of DR1 antigen was decreased in the amyloidosis group (3.8%) than in the control group (22.0%), although the difference was not significant. These findings suggest the possible involvement of genetic factors in the occurrence of amyloidosis. It is suggested that the occurrence of amyloidosis is suppressed by some genes which are linked with CW7 antigen.

Adolescent↗
PubMed2006

Effect of Yangqixue Qufengshi Recipe on rheumatoid arthritis model mice under different genetic backgrounds.

OBJECTIVE: To study the effect of Yangqixue Qufengshi Recipe (YQXQFS) on rheumatoid arthritis (RA) model mice under different genetic backgrounds. METHODS: Collagen Induced Arthritis (CIA) were established on HLA-DR4 transgenic (TG) mice and non-transgenic (NTG) mice, which partly were raised with YQXQFS, and the onset day of CIA, the level of type II collagen (CII)-reactive antibodies and the pathological scores of CIA were assessed. RESULTS: Under HLA-DR4 TG background (compared with NTG mice), the earlier onset day of CIA (11.22 +/- 3.35 days vs 16.56 +/- 4.75 days, P < 0.05) and higher level of CII-reactive antibodies (0.2274 +/- 0.1390 microg/ml vs 0.1101 +/- 0.0560 microg/ml, P < 0.05) were observed, but the pathological scores of CIA remained unchanged. YQXQFS could not influence the onset day of CIA and the level of CII-reactive antibodies, but had a certain effect on the total pathological scores (6.56 +/- 3.43 scores vs 11.11 +/- 5.64 scores) and bone erosion (0.22 +/- 0.44 scores vs 1.67 +/- 1.50 scores) of CIA on NTG mice (P < 0.05), NTG YQXQFS group compared with NTG experimental group. CONCLUSION: YQXQFS had a certain effect on RA model, but had no significant effect on HLA-DR4 related CIA.

Animals↗
PubMed2005

Genetic background influences P/Q-type Ca2+ channel alpha1A subunit mRNA expression in olfactory bulb and reproductive ability of N-type Ca2+ channel alpha1B subunit-deficient mice.

The Ca2+ channel alpha1B subunit is a pore-forming component capable of generating N-type Ca2+ channel activity. Although the N-type Ca2+ channel plays a role in a variety of neuronal functions, alpha1B-deficient mice did not show apparent behavioral abnormality. In a previous study, we observed a compensatory increase of mRNA expression of the P/Q-type Ca2+ channel alpha1A subunit gene in olfactory bulb of alpha1B-deficient mice with a CBA x C57BL/6 background; these mice showed a normal reproductive ability. In this study, we found that the mRNA expression level of the alpha1A subunit was the same in olfactory bulb of wild, heterozygous, and homozygous alpha1B-deficient mice with a CBA/JN background, and the homozygous male mice produced no offspring. These results suggest that the genetic background influences alpha1A subunit mRNA expression and reproductive ability in alpha1B-deficient mice.

Animals↗
PubMed1985

Effect of splenectomy on the development of experimental autoimmune encephalomyelitis in rats with different genetic background.

We studied the effect of total or partial splenectomy on experimental autoimmune encephalomyelitis (EAE) development in rats with different genetic background after immunization with guinea pig basic encephalitogenic protein in Freund's complete adjuvant. The operations did not affect some strains with a high susceptibility to EAE but may have reduced the EAE development in the Fischer strain, which shows only a weak susceptibility. In some hybrids and backcrosses, but not in others, splenectomy resulted in a clear-cut reduction of neurological signs of EAE. This effect may be ascribed to the elimination of contrasuppressive cell populations.

Animals↗
PubMed2005

Effects of genetic background on cardiovascular anomalies in the Ts16 mouse.

To investigate the genetic contribution to phenotypic variability in aneuploidy, we generated mice with trisomy 16 (Ts16) by mating [Rb(6.16)24Lub x Rb(16.17)7Bnr]F1 males with females from four inbred strains, BALB/cJ, C3H/HeJ, C57BL/6J, and DBA/2J. Among the four Ts16 strains that were generated, there were no significant differences in survival, weight, or length relative to euploid control littermates at either embryonic day (E) 14.5 or E17.5. All Ts16 fetuses at E14.5 had edema that ranged from mild to severe, increased amniotic fluid volume, and a thickened neck. At E17.5, Ts16 fetuses exhibited two distinct phenotypes, one with an edematous morphology and the other runt-like. None of these gross morphological abnormalities was strain-specific either in occurrence or frequency. At E10.5, there were pharyngeal arch artery (PAA) anomalies in all Ts16 embryos on the C3H/HeJ background, but none in trisomics on the other three backgrounds. However, at E17.5, there was in addition to ventricular and atrioventricular septal defects, a high frequency of aortic arch defects in Ts16 fetuses, irrespective of genetic background. Taken together, these findings indicate that there are at least two mechanistic responses to the presence of three copies of mouse chromosome 16 in the modeling of the cardiovascular system: one, development of PAA defects, is strongly influenced by genetic background; but the second, development of aortic arch anomalies in the absence of preexisting PAA anomalies, is not.

Animals↗
PubMed2004

Genetic background (C57BL/6J versus FVB/N) strongly influences the severity of diabetes and insulin resistance in ob/ob mice.

We studied the effects of genetic background on the phenotype of ob/ob mice, a model of severe obesity, insulin resistance, and diabetes caused by leptin deficiency. Despite a comparable degree of obesity and hyperinsulinemia, C57BL/6J ob/ob mice had much milder hyperglycemia and, surprisingly, normal circulating adiponectin levels despite still-prominent signs of insulin resistance. Hyperinsulinemic-euglycemic clamp revealed relatively less whole-body and muscle insulin resistance in C57BL/6J ob/ob mice, whereas liver insulin resistance tended to be more severe than in FVB/N ob/ob mice. C57BL/6J ob/ob mice had also more rapid clearance of circulating triglycerides and more severe hepatic steatosis. We suggest that strain-related distinction in lipid handling is the most important player in the differences in diabetic phenotype and insulin sensitivity, whereas the impact of circulating adiponectin levels on the overall phenotype of ob/ob mice is less important.

Adipose Tissue↗
PubMed2003

Murine coronavirus-induced hepatitis: JHM genetic background eliminates A59 spike-determined hepatotropism.

Recombinant murine coronaviruses, differing only in the spike gene and containing the strain A59 (moderately hepatotropic) and JHM (neurotropic) spike genes in the background of the JHM genome, were compared for the ability to replicate in the liver and induce hepatitis in weanling C57BL/6 mice. Interestingly, expression of the A59 spike glycoprotein within the background of the neurotropic JHM strain does not reproduce the A59 hepatotropic phenotype. Thus, the JHM genetic background plays a dominant role over the spike in the determination of hepatotropism.

Animals↗
PubMed1989

Is the DNA synthesis of pancreatic islets influenced by the MHC and/or the genetic background?

Neonatal pancreatic rat islets were used to investigate the effect of MHC haplotype RT1u on islet replication measured by incorporation of 3H-thymidine and autoradiography. The special interest in RT1u resulted from the fact that BB rats, which develop an insulin-dependent diabetes, belong to the RT1u haplotype. Thus, the RT1u, when influencing the replication, may be involved in the development of the B-cell deficiency observed in diabetic rats. The incorporation of labeled thymidine into islets obtained from rat strains carrying the RT1u or RTIa haplotype revealed no differences. No matter whether the islets were isolated from Lewis, Wistar, or BB rats, no alteration of islet replication by RT1u islets was found. However, islets obtained from Wistar rats had a higher replicatory activity than islets from Lewis rats. This finding was confirmed by a decrease in DNA synthesis of BB rat islets, in which the Wistar background was substituted by the Lewis background. We conclude from our results that MHC has no influence on islet replication, whereas genetic background seems to be involved in the regulation of islet DNA synthesis.

Animals↗
PubMed1995

The genetic background of craniosynostosis syndromes.

Craniosynostosis syndromes are developmental disorders that cause an abnormal shape of the skull due to the premature fusion of cranial sutures. Enormous progress has been made recently in understanding the genetic background of these disorders and a classification of syndromes on a genetic basis is beginning to emerge. Members of at least three gene families that play an important role in vertebrate development are associated with different craniosynostosis syndromes. Here we review the genetic aspects of this fast-moving field.

Acrocephalosyndactylia↗
PubMed2005

The severity of cholestatic injury is modulated by the genetic background.

Common bile duct ligation (CBDL) compromises the hepatic reticuloendothelial system by impairing the clearing of endotoxin and triggering an overwhelming inflammatory response. The response to endotoxin at the level of cytokine release and subsequent mortality depends on the genetic background in experimental mouse models. We hypothesized that the genetic make-up modulates the inflammatory responses after CBDL. The CBD was ligated in male A/J and B6 mice (8 weeks old). At 7 days post-CBDL, the presence of ascites was observed in 80% of B6 mice but in none of the A/J mice (P < 0.001). B6 mice showed higher mortality than A/J mice (P < 0.05). Both strains had marked cholestatic injury documented histologically. Liver chemistries were markedly elevated in both strains after injury. Plasma levels of the anti-inflammatory cytokine IL-10 were significantly higher in A/J than B6 mice at the 4- and 12-h time points (P < 0.05), whereas proinflammatory cytokine TNF-alpha levels were significantly higher in B6 than A/J mice at 2 h (P < 0.05). Both strains displayed activation of NF-kappaB after CBDL. In conclusion, the contrasting response observed after CBDL between A/J and B6 mice is largely attributable to genetic differences. Survival after CBDL was correlated with an increase in anti-inflammatory cytokines.

Animals↗
PubMed2005

Genetic background influences metabolic response to dietary phosphorus restriction.

Dietary phosphorus (P) is essential to bone growth and turnover; however, little research has focused on the genetic mechanisms controlling P utilization. Understanding the interactions between genetics and dietary P that optimize bone integrity could provide novel interventions for osteoporosis. Thirty-six pigs from two sire lines known to differ in bone structure [heavier boned (HB) and lighter boned (LB)] were assigned to one of the three diets (P adequate, P repletion or P deficient). After 14 days, bone marrow and intact radial bones were collected. Differences between these lines in growth rate, bone integrity and gene expression within bone marrow were observed. In HB, but not LB, pigs, the P-deficient diet decreased weight gain (P<.01). For both lines, P deficiency caused a reduction in radial bone strength (P<.01), but HB P-deficient animals had greater (P<.10) bone integrity than P-deficient LB pigs. In HB, but not LB, pigs, dietary treatment affected the expression of CALCR (calcitonin receptor) (P<.05), VDR (vitamin D receptor) (P<.04) and IGFBP3 (insulin-like growth factor binding protein 3) (P<.06). There was also a trend of increased IL6 (interleukin-6), TFIIB (transcription initiation factor IIB) and SOX9 (sex determining region Y-box 9) expression with P deficiency in HB, but not LB, pigs. Both genetic backgrounds responded similarly to P deficiency with an increase in the expression of OXTR (oxytocin receptor) and IGF1 (insulin-like growth factor 1). Differences in growth rate, bone integrity and gene expression within the bone marrow suggest a difference in the homeorhetic control of P utilization between these genetic lines. Understanding these differences could lead to novel treatments for osteoporosis and aid in the development of tests for identifying those at risk for this disease.

Animals↗