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PubMed2002

Re-examination of sibling cross-sterility in the ascidian, Ciona intestinalis: genetic background of the self-sterility.

Self-sterility of solitary ascidians is a typical example of the allogeneic recognition, though its molecular mechanism remains an open question. In this paper we analyze the fertility between siblings from selfed and crossed eggs to understand the genetic basis of self-sterility in the ascidian, Ciona intestinalis. First, we show that the self-sterility is strict and stable, and the individuality expressed in gametes is highly diversified in the wild population that we used. Secondly, we show one-way cross-sterility and reciprocal cross-sterility within the siblings that are self-sterile but fertile with non-siblings. Thirdly, we show self-sterility and cross-sterility share some natures and both are closely related to the sperm capacity not to bind to the vitelline coat of the autologous eggs or the eggs sterile to the sperm concerned. In all, this paper shows that the self-sterility is genetically governed by a multiple-locus system, and that most probably individual-specific determinants are haploid expression in sperm and diploid expression in eggs, given they recognize self but not non-self.

Acids↗
PubMed1984

The influence of genetic background on the susceptibility of inbred mice to streptozotocin-induced diabetes.

Multiple low-dose injections of streptozotocin (STZ) induce a delayed but progressively increasing state of hyperglycemia in mice. Different inbred strains of mice show different susceptibility to this treatment. We examined whether genetic factors associated with the H-2 complex influence the susceptibility or resistance, using a selected group of 12 inbred and 5 congenic resistant strains of mice. We found that different congenic strains differed significantly in their susceptibility to STZ-induced diabetes, suggesting that H-2-associated genes do influence the susceptibility. However, at least some inbred strains sharing the same H-2 haplotype also differed in their susceptibility, indicating that genes outside the H-2 complex may also affect the susceptibility. Therefore, there appear to be at least two genes, one within and one or more outside the H-2 complex, that determine the susceptibility to multiple low doses of STZ.

Animals↗
PubMed2006

Chronic pain and genetic background interact and influence opioid analgesia, tolerance, and physical dependence.

Opioids are commonly used in the treatment of moderate to severe pain. However, their chronic use is limited by analgesic tolerance and physical dependence. Few studies have examined how chronic pain affects the development of tolerance or dependence, and essentially no studies have looked at the role of both genetics and pain together. For these studies we used 12 strains of inbred mice. Groups of mice from each strain were tested at baseline for morphine analgesic sensitivity, mechanical nociceptive threshold, and thermal nociceptive threshold. Mice were then given morphine in a 4-day escalating morphine administration paradigm followed by reassessment of the morphine dose-response relationship. Finally, physical dependence was measured by administering naloxone. Parallel groups of mice underwent hind paw injection of complete Freund's adjuvant (CFA) to induce chronic hind paw inflammation 7 days prior to the beginning of testing. The data showed that CFA treatment tended to lower baseline ED(50) values for morphine and enhanced the degree of analgesic tolerance observed after 4 days of morphine treatment. In addition, the degree of jumping behavior indicative of physical dependence was often altered if mice had been treated with CFA. The influence of background strain was substantial for all traits measured. In silico haplotypic mapping of the tolerance and physical dependence data demonstrated that CFA pretreatment altered the pattern of the predicted associations and greatly reduced their statistical significance. We conclude that chronic inflammatory pain and genetics interact to modulate the analgesic potency of morphine, tolerance, and physical dependence.

Analgesics, Opioid↗
PubMed2004

The murine model of infection with Leishmania major and its importance for the deciphering of mechanisms underlying differences in Th cell differentiation in mice from different genetic backgrounds.

Mice from the majority of inbred strains are resistant to infection by Leishmania major, an obligate intracellular protozoan parasite of macrophages in the mammalian host. In contrast, mice from BALB strains are unable to control infection and develop progressive disease. In this model of infection, genetically determined resistance and susceptibility have been clearly shown to result from the appearance of parasite-specific CD4+ T helper 1 or T helper 2 cells, respectively. This murine model of infection is considered as one of the best experimental systems for the study of the mechanisms operating in vivo at the initiation of polarised T helper 1 and T helper 2 cell maturation. Among the several factors influencing Th cell development, cytokines themselves critically regulate this process. The results accumulated during the last years have clarified some aspects of the role played by cytokines in Th cell differentiation. They are providing critical information that may ultimately lead to the rational devise of means by which to tailor immune responses to the effector functions that are most efficient in preventing and/or controlling infections with pathogens.

Animals↗
PubMed1997

Early consequences of macrophage-Francisella tularensis interaction under the influence of different genetic background in mice.

The induction, regulation and expression of protective immunity against Francisella tularensis LVS infection is dependent on the results of primary interaction between the cells of host's immunoregulatory system and the microbe. The early events, at least on the side of macrophages, are under the genetic control. To determine the impact of genes that might be involved in the control of resistance to Francisella tularensis LVS infection, we have used three different inbred strains of mice with increasing resistance to this infection in order C3H/HeJ (Lpsd), C3H/HeN (Lpsn"), and C57B1/10N (Lpsn"). The controlled production of IL-10, IFN-gamma, and TNF-alpha coupled with increased production of reactive oxygen metabolites during early phase of infection distinguished less susceptible C3H/HeN mice from their more susceptible cogenic C3H/HeJ counterparts. The enhancement of oxidative metabolism that appeared on day 5 after the infection of both C3H/HeN and C57B1/10N mice closely correlated with increasing resistance of these two strains of mice to Francisella tularensis LVS infection. These mice were also capable to reach the highest level of TNF-alpha on day 5 after the infection. At the same time interval, only C57B1/10N mice produced significantly enhanced level of nitric oxide. Overall, these parameters may suggest their possible biological role in early-phase resistance to Francisella tularensis LVS infection and their subsequent consequences for ultimate control of infection and its clearance.

Animals↗
PubMed2000

Osteoporosis in beta-thalassaemia major patients: analysis of the genetic background.

Regular blood transfusions from infancy until adulthood in beta-thalassaemia major patients have substituted severe bone deformities with less marked skeletal lesions as osteoporosis. Osteoporosis is characterized by low bone mass and disruption of bone architecture, resulting in reduced bone strength and increased risk of fractures. Genetic factors have an important role in determining bone mineral density (BMD). We have investigated the possible association between BMD and two polymorphisms in 135 beta-thalassaemic patients: (i) a substitution G-->Tau in a regulatory region of the COLIA1 gene encoding for the major protein of bone (type 1 collagen), and (ii) a one-base deletion in intron 4 (713-8del C) of transforming growth factor beta 1 (TGF-beta1) gene. We have found a remarkable incidence (90%) of osteopenia and osteoporosis among regularly transfused patients. Bone mass was lower in men than in women (P = 0.0023), with a more prevalent osteopenia/osteoporosis of the spine in men than in women (P = 0. 001). The sample was stratified on the basis of BMD expressed as Z-score, i.e. normal, osteopenic and osteoporotic patients, and genotype frequencies of each group were evaluated. TGF-beta1 polymorphism failed to demonstrate a statistical difference in BMD groups. However, subjects with heterozygous or homozygous polymorphism of the COLIA1 gene showed a lower BMD than subjects without the sequence variation (P = 0.012). The differences among genotypes were still present when the BMD was analysed as adjusted Z-score and when men and women were analysed separately (P = 0.022 and 0.004 respectively), with men more severely affected. Analysis of COLIA1 polymorphism could help to identify those thalassaemic patients at risk of osteoporosis and fractures.

Adult↗
PubMed2001

The genetic background of medullary thyroid carcinoma in young patients.

The study was undertaken to evaluate the frequency of RET polymorphisms at codons 769 and 836 in young medullary thyroid carcinoma (MTC) patients in whom the presence of a known germline mutation has been excluded. 40 patients aged 10-29 were subjected to genetic analysis of RET exons 10, 11, 13, 14 and 16 and compared to 140 older patients. The hereditary component occurred to be very high in young MTC patients: 57% carry the germline mutation, other 28% exhibit at least one rare polymorphic variant of RET. The observed allelic frequencies were 38% for polymorphic variant L769CTG and 6% for variant S836AGT. The results were significantly higher than those obtained in the group of older patients: 20% and 1% for L769CTG and S836AGT, respectively. Our results speak in favour that the polymorphism in RET codon 769 and 836 may also be a factor predisposing to the development of MTC in young age.

Adult↗
PubMed2002

[Molecular genetic background of developmental bony malformations at the craniocervical junction and cervical spine].

In this review a new interpretation of the origin of bony developmental malformations affecting the craniocervical junction and the cervical spine is presented based on recent advances in the understanding of embryonic development of the spine and its molecular genetic control. Radiographs, CT and MRI scans or CT myelograms of patients with Klippel-Feil syndrome were used for demonstration. Detailed clinical and radiological analysis of these patients was published earlier [David KM, Stevens JM, Thorogood P, Crockard HA. The dysmorphic cervical spine in Klippel-Feil syndrome: interpretations from developmental biology. Neurosurg Focus 1999;6(6):1.]. Homeotic transformation due to mutations or disturbed expression of Hox genes is a possible mechanism responsible for Cl assimilation. Notochordal defects and/or signalling problems, that result in reduced or impaired Pax-1 gene expression, may underlie vertebral fusions. This, together with asymmetrical distribution of paraxial mesoderm cells and a possible lack of communication across the embryonic mid-line, could cause the asymmetrical fusion patterns. The wide and flattened shape of the fused vertebral bodies, their resemblance to the embryonic cartilaginous vertebrae and the process of progressive bony fusion with age suggest that the fusions occur before or, at the latest, during chondrification of vertebrae. The authors suggest that the aforementioned mechanisms are likely to be, at least in part, responsible for the origin of the bony developmental malformations affecting the craniocervical junction and the cervical spine.

Animals↗
PubMed1986

Inherited disorders in the black population of southern Africa. Part I. Historical and demographic background; genetic haematological conditions.

Genetic, geographic and socio-economic diversity has resulted in disparity in the relative prevalence of many inherited disorders and congenital conditions in the populations of southern Africa. In the first section of a 3-part article an account is given of the historical and demographic background in relation to factors which influence the presence and frequency of faulty genes in the black community. In addition, inherited haematological conditions--in particular haemoglobinopathies, red-cell enzyme and membrane defects--are discussed in terms of their clinical, genetic and anthropological significance. The conditions transmitted by simple genetic mechanisms are documented in Part II, with discussion of those notable for their unusually high or low prevalence. In the final section multifactorial, chromosomal and non-genetic congenital disorders are reviewed and a number of unusual conditions of obscure aetiology are mentioned. In this 3-part overview an attempt has been made to document present knowledge and to provide a bibliography for inherited and congenital disorders in the black population.

Anemia, Sickle Cell↗
PubMed2006

Genetic background of acute coronary syndromes.

Acute coronary syndromes (ACS) are one of the major causes of mortality nowadays. Although much is known about factors involved in atherogenesis and acute coronary events, there are still many cases in which a lack of classical risk factors, together with family history, suggests the presence of an unrevealed genetic predisposition and molecular mechanisms. This paper reviews genetic predisposition to ACS. It also indicates which genes are linked to the processes of destabilization and rupture of atherosclerotic plaque and thus may be potential targets for more effective prophylaxis and treatment.

Journal Article↗
PubMed2005

Genes determining yeast replicative life span in a long-lived genetic background.

Here we describe the replicative life spans of more than 50 congenic Saccharomyces cerevisiae strains, each carrying a mutation previously implicated in yeast aging. This analysis provides a direct comparison, in a single, long-lived strain background, of a majority of reported yeast aging genes. Of the eleven deletion mutations previously reported to increase yeast life span, we find that deletion of FOB1, deletion of SCH9, and deletion of GPA2, GPR1, or HXK2 (three genetic models of calorie restriction) significantly enhanced longevity. In addition, over-expression of SIR2 or growth on low glucose increased life span. These results define a limited number of genes likely to regulate replicative life span in a strain-independent manner, and create a basis for future epistasis analysis to determine genetic pathways of aging.

Cellular Senescence↗
PubMed2006

[Genetic background of irritable bowel syndrome].

Irritable bowel syndrome (IBS) is a functional disorder which affects the 20% of the population. The exact origin is unknown. IBS is the result of interaction of genes and environmental factors. Familial aggregation and higher concordance rate of monozygotic twins compared to dizygotic twins provide evidence for the importance of genetic factors in the pathogenesis of IBS. Interest has focused on genetic variants of serotonin transporter and receptors, because of their role in gut motility, visceral sensitivity, immune processes and mood. Firm conclusions about the role of serotonin system, as well as other neuroreceptors, G-proteins, cytokine polymorphisms in the pathogenesis of IBS cannot be made.

Cytokines↗