Surgical correction of facial deformities in a patient with cleidocranial dysplasia

A one-stage procedure for correction of the maxillofacial skeletal deformities associated with cleidocranial dysplasia is presented. The common bony abnormalities are discussed, and the combined surgical and orthodontic management over an 8-year period is outlined.     

Mutation screening of interferon-gamma (IFNgamma) as a candidate gene for asthma

BACKGROUND: Reduced levels of interferon gamma (IFNgamma) mRNA and protein have been detected in the bronchoalveolar lavage fluid of atopic asthmatics. IFNgamma is secreted by TH1 cells while IL-4 and IL-5 are secreted by TH2 cells and an imbalance in the TH1/TH2 response may be responsible for atopic asthma. The gene for IFNgamma is located on chromosome 12; a region of the genome which has been shown in linkage studies to be associated with asthma. OBJECTIVE: To determine if there are any mutations present in the coding exons and 5' flanking region of the IFNgamma gene in atopic asthmatic subjects compared with controls to explain the lower levels of this cytokine as an inherited, rather than acquired, factor in the asthmatic subjects. METHODS: The four exons and 5' flanking region of the IFNgamma gene were amplified by polymerase chain reaction (PCR) from genomic DNA of 265 individuals from a Western Australian and a Venezuelan population. The PCR products were examined by single strand conformational polymorphism and heteroduplex analyses to see if there were any changes in the DNA migration patterns which would suggest the presence of a sequence variation. RESULTS: The four exons and the 5' flanking region of the IFNgamma gene were amplified from 265 individuals from two populations. Single strand conformational polymorphism and heteroduplex analyses did not reveal any mutations in the regions examined. CONCLUSION: The gene for IFNgamma appears to be highly conserved as no sequence variations were detected in 265 individuals. These results suggest that mutations of the IFNgamma gene are unlikely to be a significant cause of an inherited asthma diathesis.     

颅骨锁骨发育不良患者乳牙牙根吸收特点及牙齿结构分析

目的:研究颅骨锁骨发育不良(cleidocranial dysplasia,CCD)患者乳牙牙根的吸收特点以及乳牙结构的异常.方法:收集CCD患者因治疗需要而拔除的滞留乳牙,在扫描电镜下观察CCD患者乳牙牙根吸收面的情况;同时制备牙齿结构的病理磨片,在偏光显微镜下观察CCD患者牙齿结构的特点.结果:CCD患者具有典型的临床表现.扫描电镜的观察结果显示,与正常对照相比,CCD患者乳牙牙根的吸收陷窝表浅,底部平坦、光滑、大小不一,吸收陷窝的数目相对较少.病理磨片显示,CCD患者乳牙的髓腔内有大量不规则的、结构不清晰的钙化团块沉积,钙化团块的形成量与牙根吸收的程度密切相关;患者乳牙牙根尖1/3处的牙骨质由细胞性或无细胞性牙骨质构成.结论:CCD患者乳牙牙根的吸收特点与正常乳牙不一致,患者髓腔内钙化团块的形成可能与牙髓细胞在牙根吸收时的调控功能异常有关,根部牙骨质的类型可能不是乳牙滞留的因为.     

DNA-dependent kinase (p350) as a candidate gene for the murine SCID defect

Severe combined immunodeficient (SCID) mice are deficient in a recombination process utilized in both DNA double-strand break repair and in V(D)J recombination. The phenotype of these mice involves both cellular hypersensitivity to ionizing radiation and a lack of B and T cell immunity. The catalytic subunit of DNA-dependent protein kinase, p350, was identified as a strong candidate for the murine gene SCID. Both p350 and a gene complementing the SCID defect colocalize to human chromosome 8q11. Chromosomal fragments expressing p350 complement the SCID phenotype, and p350 protein levels are greatly reduced in cells derived from SCID mice compared to cells from wild-type mice.     

Antitat gene therapy: a candidate for late-stage AIDS patients

Antitat is an autoregulated gene expressing an inhibitory RNA with dual function: it sequesters the Tat protein by polymeric-TAR and blocks the translation of the Tat messenger RNA by antisense-Tat. Using human T cell lines and peripheral blood lymphocytes as the in vitro target, we have previously shown that antitat is an effective long-term suppressor of HIV-1, including 'field' isolates. To assess the efficacy of this inhibitory gene better in the setting of an infected individual with late-stage AIDS, we examined its antiviral activity in an in vivo established infection. Peripheral blood mononuclear cells isolated from AIDS patients were transduced with replication defective retroviral vectors carrying the antitat gene. In the absence of cell selection, the antitat gene blocked virus replication and allowed infected CD4+ T cells to expand in culture. These results suggest that antitat gene therapy may be beneficial to block HIV-1 replication and reconstitute the immune system of late-phase AIDS patients. We introduced a new parameter, CRF, which defines the effectiveness of the ex vivo gene therapy treatment of AIDS patients. Antitat treatment was efficient in cells of all patients regardless of viral quasispecies, however, it was most potent in severely immunocompromised individuals.     

The tumour-suppressor gene patched encodes a candidate receptor for Sonic hedgehog

The protein Sonic hedgehog (Shh) controls patterning and growth during vertebrate development. Here we demonstrate that it binds Patched (vPtc), which has been identified as a tumour-suppressor protein in basal cell carcinoma, with high affinity. We show that Ptc can form a physical complex with a newly cloned vertebrate homologue of the Drosophila protein Smoothened (vSmo), and that vSmo is coexpressed with vPtc in many tissues but does not bind Shh directly. These findings, combined with available genetic evidence from Drosophila, support the hypothesis that Ptc is a receptor for Shh, and that vSmo could be a signalling component that is linked to Ptc.     

Identification of a growth arrest specific (gas 5) gene by differential display as a candidate gene for determining susceptibility to hyperthermia-induced exencephaly in mice

Neural tube defects (NTDs) are among the most common congenital malformations, affecting approximately 1 per 1,000 liveborn infants in the United States [Nakano, 1973; Richards et al., 1972]. Maternal exposure to hyperthermia, either through recreational sources or due to an infectious agent, is thought to account for approximately 10% of observed NTD cases. The specific genes conferring susceptibility or resistance to hyperthermia-induced NTDs have not been identified. This study used differential display-polymerase chain reaction (DD-PCR) to characterize alterations in gene expression in the anterior embryonic neural tube of two highly inbred murine strains (SWV/Fnn, LM/Bc/Fnn) known to differ in their genetically determined susceptibility to heat-induced NTDs. Herein, we report the neural tube-specific differential expression of the growth arrest specific (gas 5) gene in the highly susceptible SWV/Fnn strain during neural tube closure (NTC). Although the expression of gas 5 did not appear to be altered by the teratogenic heat treatment, its spatial and strain-specific pattern of expression makes it an excellent candidate gene responsible for the observed genetic differences in NTD susceptibility between these two inbred murine strains.     

Differential expression of XAP5, a candidate disease gene

We have isolated a full-length cDNA corresponding to the XAP5 gene in Xq28. An unusual feature of the cDNA is that it contains runs of CCG repeats in the 5' untranslated region, typical of genes that exhibit anticipation. It has a striking pattern of differential expression and is greatly enhanced in various fetal tissues. This predicted protein encodes a unique 339-amino-acid polypeptide that contains a large percentage of highly charged residues and a possible nuclear localization signal. A comparison to genomic sequence shows that XAP-5 comprises 13 exons spanning 6.5 kb. An examination of the human population indicates that the longest CCG run is polymorphic and varies in length from 8 to 12 repeats.     

A candidate recombination modifier gene for Zea mays L

Maize meiotic mutant desynaptic (dy) was tested as a candidate recombination modifier gene because its effect is manifested in prophase I. Recombination rates for desynaptic (dy) and its wild type were compared in two ways: (1) segregation analysis using six linked molecular markers on chromosome 1L and (2) cytogenetic analysis using fluorescence in situ hybridization (FISH)-aided meiotic configurations observed in metaphase I. Chromosome 1L map lengths among the six linked markers were 45-63 cM for five F2 dy/dy plants, significantly lower than the wild-type F2 map distance of 72 cM. Chromosomes 2 and 6 were marked with rDNA FISH probes, and their map lengths were estimated from FISH-adorned meiotic configurations using the expectation-maximization algorithm. Chiasma frequencies for dy/dy plants were significantly reduced for both arms of chromosome 2, for chromosome arm 6L, and for eight unidentified chromosomes. There was a notable exception for the nucleolus-organizing region-bearing arm chromosome arm 6S, where dy increased chiasma frequency. Maize meiotic mutant desynaptic is a recombination modifier gene based on cytogenetic and segregation analyses.     

A human endogenous retroviral superantigen as candidate autoimmune gene in type I diabetes

Microbial superantigens (SAGs) have been implicated in the pathogenesis of human autoimmune diseases. Preferential expansion of the Vveta7 T cell receptor positive T cell subset in patients suffering from acute-onset type I diabetes has indicated the presence of a surface membrane-bound SAG. Here, we have isolated a novel mouse mammary tumor virus-related human endogenous retrovirus. We further show that the N-terminal moiety of the envelope gene encodes an MHC class II-dependent SAG. We propose that expression of this SAG, induced in extrapancreatic and professional antigen-presenting cells, leads to beta-cell destruction via the systemic activation of autoreactive T cells. The SAG encoded by this novel retrovirus thus constitutes a candidate autoimmune gene in type I diabetes.     

The ade6 gene of the fission yeast as a target for antisense and ribozyme RNA-mediated suppression

A genetic system for the analysis of antisense and ribozyme mechanisms is a much needed experimental tool, and yeast represent a favorable organism on which to base such a system. We have shown previously that the fission yeast Schizosaccharomyces pombe has potential to satisfy the requirements of such a system. This report describes experiments designed to determine if antisense and ribozyme RNA-mediated gene suppression will be generally applicable to other genes in S. pombe. Antisense and ribozyme RNAs designed to suppress the ade6 gene were expressed at high levels from episomal expression vectors. The ade6 gene was chosen as a target as mutations within the gene confer adenine auxotrophy and a red colony phenotype, and it was expected that antisense or ribozyme RNA-mediated mutant phenocopies would exhibit the same readily detectable phenotype. No phenotypic indication of ade6 suppression was detected in transformed yeast, and ade6 target mRNA was analyzed by primer extension and Northern analysis. Initially, conflicting results were obtained from these techniques, which were determined to be due to duplex formation between antisense and target RNA in vitro. No detectable reduction in the ade6 mRNA levels was found, and it was concluded that the gene was not suppressed by the antisense or ribozyme RNAs tested. These results confirm that in S. pombe as with other organisms, the susceptibility of genes to RNA-mediated suppression may be gene specific and that design of antisense and ribozyme genes will be an empirical process.     

Congenital dysplasia of C2--6

The gastric secretion of 99mTc-pertechnetate as a means of assessing parietal cell function was investigated in 12 pernicious anemia (PA) patients with histamine-fast achlorhydria. Twelve control subjects were either normal volunteers or patients proven not to have either PA or any other gastrointestinal disease. The results indicated that, while the stomachs of PA patients secreted no hydrochloric acid, they continued to secrete 99mTc-pertechnetate, indicating that 99mTcO4 - is secreted not by parietal cells alone or else not by parietal cells at all. The gastric pertechnetate activity, therefore, cannot be used as an index of gastric acid secretory activity in PA.     

Localization of a gene responsible for arrhythmogenic right ventricular dysplasia to chromosome 3p23

BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD), a familial cardiomyopathy occurring with a prevalence of 1 in 5000, is characterized by replacement of myocytes with fatty and fibrous tissue. Clinical manifestations include structural and functional abnormalities of the right ventricle and arrhythmias, leading to a sudden death rate of 2.5% per year. Four loci have been mapped, but no gene has been identified as yet. METHODS AND RESULTS: We identified a large family of >200 members with ARVD segregating as an autosomal dominant trait affecting 10 living individuals. The diagnosis of ARVD was based on international diagnostic criteria including history, physical examination, ECG, echocardiogram, right ventricular angiogram, endomyocardial biopsy, and 24-hour ambulatory ECG. Blood was collected for DNA from 149 family members. Analysis of 257 polymorphic microsatellite markers by genetic linkage excluded previously known loci for ARVD and identified a novel locus at 3p23. Analysis of an additional 20 markers further defined the region. A peak logarithm of the odds score of 6.91 was obtained with marker D3S3613 at theta=0% recombination. Haplotype analysis identified a shared region between markers D3S3610 and D3S3659 of 9. 3 cM. CONCLUSIONS: A novel locus for ARVD has been mapped to 3p23 and the region narrowed to 9.3 cM. Identification of the gene will allow genetic screening and a specific diagnosis for a disease with protean nonspecific findings. It should also provide insight fundamental to understanding cardiac chamber-specific gene expression and/or the mechanism of myocyte apoptosis observed in this disease.     

HIRA, a DiGeorge syndrome candidate gene, is required for cardiac outflow tract septation

DiGeorge syndrome (DGS) is a congenital disease characterized by defects in organs and tissues that depend on contributions by cell populations derived from neural crest for proper development. A number of candidate genes that lie within the q11 region of chromosome 22 commonly deleted in DGS patients have been identified. Orthologues of the DGS candidate gene HIRA are expressed in the neural crest and in neural crest-derived tissues in both chick and mouse embryos. By exposing a portion of the premigratory chick neural crest to phosphorothioate end-protected antisense oligonucleotides, ex ovo, followed by orthotopic backtransplantation to the untreated embryos, we have shown that the functional attenuation of cHIRA in the chick cardiac neural crest results in a significantly increased incidence of persistent truncus arteriosus, a phenotypic change characteristic of DGS, but does not affect the repatterning aortic arch arteries, the ventricular function, or the alignment of the outflow tract.