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PubMed1993

Distinctive expression of lprcg in the heterozygous state on different genetic backgrounds.

Much knowledge of the etiopathogenesis of human autoimmune diseases has been obtained from the mutant mouse models carrying lpr and gld. These autoimmune genes have been regarded as autosomal recessive. The novel lymphoproliferative and autoimmune mutation lprcg is unique in its interaction with gld despite their different chromosomal locations: chromosomes 19 and 1, respectively. Both lprcg and lpr mutations are shown to be the defects in the Fas antigen gene that controls apoptosis. Evidence has been provided for the partial expression of lpr in the heterozygous state and the significant influences of background genes on lpr-induced autoimmune disorders. To investigate the expression of the heterozygous lprcg and the effects of background genes on it, anatomical, serological, and pathological manifestations were compared among lprcg/lprcg,lprcg/+, and +/+ mice on both MRL/MpJ (MRL) and CBA/KlJms (CBA) backgrounds. On the MRL background, lymph nodes (LN) and spleens of lprcg/+ were significantly larger in weight than those of +/+, but far lower than those of lprcg/lprcg mice. In accord with this, these lprcg/+ mice had intermediate levels of anti-single-stranded DNA antibodies, circulating immune complexes, and serum Igs between those of lprcg/lprcg and +/+ mice and were similar to lprcg/lprcg mice in severity of glomerulonephritis. However, accumulation of anomalous CD4-8- T cells characteristic of the lpr disease was not proved in the enlarged lprcg/+ LN. On the CBA background, the LN and spleen weight increases in lprcg/+ were statistically significant compared to +/+ mice but were minimal, being regarded as clinically insignificant. In support of this, lprcg/+ mice were not different from +/+ mice in any of the serological and pathological parameters examined. The results clearly demonstrate that the lprcg gene can function to induce autoimmune disorders in the heterozygous state on the MRL but not on the CBA background.

Animals↗
PubMed1984

Murine streptozotocin diabetes: influences of the major histocompatibility complex, genetic background and blood transfusion.

Major histocompatibility complex-linked immune response genes are thought to influence susceptibility to induction of both human insulin-dependent diabetes and murine streptozotocin-induced diabetes. To clarify this relationship, we administered streptozotocin intravenously in two doses (120 and 240 mg/kg body weight) on days 0 and 14, and monitored blood glucose until day 100 in young adult male mice of differing background genome and/or H-2 complex. In addition, we examined the effect of allogeneic whole blood transfusion on subsequent susceptibility to diabetes. B10 recombinant mice possessing the k allele at the centromeric H-2-K and I-A loci were most susceptible to diabetes induction. Variation in susceptibility of different inbred strains with the same major histocompatibility complex genotype suggested a rôle for non-major histocompatibility complex genes. Blood transfusion delayed the onset, but did not significantly reduce the incidence of, delayed hyperglycaemia. We conclude that, in this murine model, multiple genes within the outside the major histocompatibility complex influence multiple-dose streptozotocin-diabetes susceptibility, and that prior blood transfusion may modulate diabetes induction.

Animals↗
PubMed1992

Effect of genetic background on the developmental expression of c-fos and c-myc in chicken.

The developmental expression of the protooncogenes, c-fos and c-myc, in muscle and liver of 14- and 19-day embryos and 1-, 6-, 8- and 28-day-old chicks of Athens Canadian Random Bred (ACRB) Single Comb White Leghorn (SCWL) and Peterson X Arbor Acres commercial broiler (PXAA) was determined. For the three stocks of chicken, significant differences were found in c-fos and c-myc expression. For both muscle and liver, averaged across ages, abundance of c-fos RNA was highest in PXAA and lowest in ACRB with differences significant at the P less than 0.01 level. c-myc RNA levels were significantly higher (P less than 0.01) in PXAA than in ACRB or SCWL liver. Taken over the developmental period, expression of c-fos RNA in muscle increased at different rates between breeds from 14-day embryo levels to peak levels in 6- to 8-day-old chicks and declined in 28-day-old chicks. Levels of c-fos were much lower in liver and showed no consistent differences related to developmental stage. A steady decline in c-myc from 14-day embryo levels to 28-day-old chicks was found in both muscle and liver. This decline in c-myc levels generally parallels the decline in relative growth rates which occurs in all breeds over the developmental period. In liver, the fast growing PXAA had the highest levels of c-myc, c-fos, on the other hand, showed elevated levels in PXAA for both muscle and liver and distinctly different patterns between these two tissues over the developmental period, suggesting tissue-specific involvement in growth.

Animals↗
PubMed2004

[Mitochondrial hearing impairment. Background, genetic predisposition and possibilities for diagnosis].

Hearing impairment (HI) is one of the most common neurosensory disorders, with sensorineural hereditary HI being the most common form. Mitochondrial maternally inherited HI appears to be increasing in frequency. The incidence of mitochondrial defects causing HI is estimated to be between 6 and 33% of all hearing deficiencies, with an even higher percentage for some syndromic cases. This review summarises the syndromic and non-syndromic characteristics of sensorineural HI based on mutations in mitochondrially encoded genes, the relationship to aminoglycoside-induced HI and related diagnostic tools.

DNA, Mitochondrial↗
PubMed2000

Muscle and motor-skill dysfunction in a K+ channel-deficient mouse are not due to altered muscle excitability or fiber type but depend on the genetic background.

The voltage-gated K+ channel Kv3.1 is expressed in skeletal muscle and in GABAergic interneurons in the central nervous system. Hence, the absence of Kv3.1 K+ channels may lead to a phenotype of myogenic or neurogenic origin, or both. Kv3.1-deficient (Kv3.1-/-) 129/Sv mice display altered contractile properties of their skeletal muscles and show poor performance on a rotating rod. In contrast, Kv3.1-/- mice on the (129/Sv x C57BL/6)F1 background display normal muscle properties and perform like wild-type mice. The correlation of poor performance on the rotating rod with altered muscle properties supports the notion that the skeletal muscle dysfunction in Kv3.1-/- 129/Sv mice may be responsible for the impaired motor skills on the rotating rod. Surprisingly, we did not find major differences between wild-type and Kv3.1-/- 129/Sv skeletal muscles in either the resting or action potential, the delayed-rectifier potassium conductance (gK) or the distribution of fast and slow muscle fibers. These findings suggest that the Kv3.1 K+ channel may not play a major role in the intrinsic excitability of skeletal muscle fibers although its absence leads to slower contraction and relaxation and to smaller forces in muscles of 129/Sv Kv3.1-/- mice.

Action Potentials↗
PubMed1998

Differences in genetic backgrounds affecting gonadal differentiation between two local populations of the Japanese wrinkled frog (Rana rugosa).

Gonadal differentiation in two local populations - Hamakita and Hiroshima - of the Japanese wrinkled frog (Rana rugosa) was examined from hatching to the end of metamorphosis. The Hamakita male has X and Y chromosomes distinguishable morphologically from each other, while X and Y chromosomes in the Hiroshima male cannot be distinguished morphologically. In the two populations, primordial gonads differentiated into testes or ovaries by stage I of Taylor and Kollros, and larvae at stage XXV - the end of metamorphosis - possessed definitive testes or ovaries. However, immature testes at stages II-III in the Hiroshima population showed a higher incidence of testes with ovarian characteristics - meiotic figures and gonadal cavities - than those in the Hamakita population. In addition, proliferative activities in the testicular cells of the immature testes in the Hiroshima population were very low. On the other hand, there were no remarkable differences in the histological processes of ovary development between the two populations. Intraspecific hybridization between females of the Hamakita population and males of the Hiroshima population retarded testis differentiation after stage XV, while the reciprocal hybridization showed normal gonadal sex differentiation and development. These observations suggest that R. rugosa, possessing heteromorphic sex chromosomes in the male, establishes firm gonochorism, where the feminization involves the suppression of testis differentiation, and that masculinization is performed by resistance to this suppression as well as active proliferation of testicular cells.

Animals↗
PubMed2003

The abnormalities of chromosome 8 in two hepatocellular carcinoma cell clones with the same genetic background and different metastatic potential.

PURPOSE: Two hepatocellular carcinoma (HCC) cell clones named MHCC97-H and MHCC97-L with different metastatic potential have recently been established from the same parent cell line MHCC97 in our institute. The cytogenetic alterations of these two clones were investigated in this study to explore the possible clues to the mechanism involved in HCC metastasis. METHODS: Their chromosomal aberrations were analyzed with comparative genomic hybridization (CGH), chromosome-specific painting, and two-color fluorescence in situ hybridization (FISH). RESULTS: The aberrations were found in a total of 17 chromosomes, and six kinds of the aberrations including gains of 1q, 7q, 8q, 20, and the losses of 8p23, 21q were found both in the two cell clones and their parent cell line MHCC97. Using modified CGH, with the DNA of MHCC97-L as control to test the MHCC97-H clone, the loss of 8p23 and the gain of 1q31-32, 8q21.3-22, 13q22, 17q22 were highlighted, and the most significant finding was on chromosome 8. Dual color FISH combining a pericentromeric probe and a BAC probe mapping at 8q23.1 was then performed to verify this result, and the signal ratios of the BAC to centromere were 1.43 in MHCC97-H and 1.45 in MHCC97-L, confirming the over-representations at 8q in both cells. Another interesting finding in the dual-color metaphase FISH was the intrachromosomal translocation of 8q to 8p (looked like an isochromosome 8) and non-reciprocal translocation of part of 8q to 4q, which was further clarified and proved by the FISH with whole chromosome 8 painting probe. CONCLUSIONS: The high copies amplification on 8q, the formation of isochromosome 8, non-reciprocal translocation of partial 8q to 4q, and loss of 8p occurred at the same time and are the characteristic chromosomal aberrations of the two cell clones. The chromosome 8p, especially 8p23, might harbor some novel genes related to the HCC metastasis.

Carcinoma, Hepatocellular↗
PubMed1999

Influence of the genetic background and parasite load of mice on the immune response developed against nymphs of Ixodes ricinus.

The immune response of BALB/c (H-2d), DBA (H-2d), C57BL/6 (H-2b), C3H (H-2k), CBA (H-2k), SJL (H-2s), and FVB (H-2q) mice infested once with 15 nymphs of Ixodes ricinus is polarized toward Th2 as suggested by cytokines produced by lymph node cells stimulated with concanavalin A. The parasite load does not influence the polarization of the immune response as observed in BALB/c mice, which developed a Th2 response when infested with 5 or 45 nymphs. As assessed by attachment and weights of engorged nymphs, no resistance was acquired by BALB/c, C57BL/6, or C3H mice undergoing three successive infestations. However, these mice produced a gradual increase in IgE.

Animals↗
PubMed2025

Genetic background of Richter transformation of atypical chronic lymphocytic leukemia to diffuse large B-cell lymphoma - a case study.

Atypical chronic lymphocytic leukemia (aCLL) is an indolent lymphoproliferative neoplasm derived from CD19-positive and CD5 or CD23-negative B cells. This paper presents the results of whole genome sequencing (WGS) of lymphoma cells collected from a 29-year-old woman initially diagnosed with aCLL and successfully treated with fludarabine, cyclophosphamide, and rituximab. Eight years later, due to disease progression, she was treated with ibrutinib. After 5 months, her status suddenly deteriorated. PET-CT results suggested Richter transformation (RT). Histopathological examination of nodal lesions confirmed the diagnosis of Diffuse Large B Cell Lymphoma (DLBCL). Finally, the patient was successfully treated with DHAP-R and alloHSCT. WGS of lymphoma cells revealed the presence of pathogenic (COL11A1, MGME1) and likely pathogenic variants (ZMYM3, ALG6, UBA5, and ATG7). Out of these genes, only ZMYM3 is recurrently mutated in B-cell chronic lymphocytic leukemia (B-CLL). The presence of the other lesions requires further studies and indicates the complex molecular background of aCLL transformation to DLBCL. Therefore, the whole-genome variant assessment is worth considering for introduction into a routine procedure at the time of B-CLL diagnosis, especially when RT is suspected.

Humans↗
PubMed1981

Genetic background of acute anterior uveitis.

To determine the hereditary pattern of acute anterior uveitis, we examined seven families-one family with four cases, one family with three cases, and four families with two cases of acute anterior uveitis. A total of 16 patients with uveitis and 28 relatives underwent ocular examinations and serologic determination of HLA antigens, protease inhibitor alpha 1-antitrypsin typing, and X-ray examination of sacroiliac joints. Sacroiliitis was found in 11 of 16 patients (68.8%) and incomplete Reiter's disease in seven of 16 (43.8%). HLA-B27 antigen was found in all patients with uveitis and in six of 21 (28.6%) relatives. HLA-Cw1 antigen was found in nine of 14 (64.3%) patients with uveitis, often in the same haplotype with HLA-B27 antigen. HLA-DR4 antigen was found in seven of 11 (63.6%) patients with uveitis. There was no significant association of the alpha 1-antitrypsin variant MZ with uveitis. We believe that a pleiotropic gene associated with HLA-B27 antigen with autosomal dominant inheritance, incomplete penetrance, and variable expressivity may determine susceptibility to acute anterior uveitis in linkage disequilibrium with HLA-Cwl antigen.

Acute Disease↗