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41.
It has been hypothesized that two mutations in one gene are not sufficient and that three mutations between two genes are required for penetrance in some cases of Bardet-Biedl syndrome (the so-called "triallelic inheritance" model). McKusick-Kaufman syndrome (MKS) is allelic to one form of Bardet-Biedl syndrome (BBS). We describe an Amish family with MKS, where three children were affected with homozygous MKKS (BBS6) mutations (H84Y and A242S on both alleles), their father was a carrier, and their mother was homozygous for the same MKKS mutations, but she was non-penetrant. Genotyping and/or sequencing of BBS1, BBS2, BBS3, BBS4, BBS5, BBS7, and BBS8 excluded "triallelic inheritance" for each gene either by an incompatible inheritance pattern or an absence of mutations in the coding region and the intronic splice junctions of these genes. We conclude that the "triallelic" model does not explain the incomplete penetrance of MKS.  相似文献   
42.
Primitive Neuroectodermal Tumors of the Central Nervous System   总被引:2,自引:0,他引:2  
Controversial issues relating to the pathobiology and classification of central nervous system primitive neuroectodermal tumors (PNETs) have plagued neuropathologists for more than 70 years. Hypotheses advanced in the mid-1920's have remained as fixed concepts in contemporary literature, largely consequent to repetitious support by a small number of neuropathologists despite a growing body of information discrediting these ideas from neuroembryologists, oncologists, neuroscien-tists and pathologists.
Attention has largely focused upon PNETs arising in the cerebellum (commonly known as medul-loblastomas [MBs]), because about 80% of central nervous system (CNS) PNETs originate in this site. It has been asserted that the 20% which do not are biologically different, although most individuals agree that the histological features of PNETs that occur in different sites throughout the CNS are indistinguishable from those growing in the cerebellum.
The historical aspects of this controversy are examined in the face of evidence that there is, in fact, a unique class of CNS tumors which should appropriately be regarded as primitive neuroectodermal in nature. Specifically, a number of different approaches to the problem have yielded data supporting this hypothesis. These approaches include the identification of patterns of expression among a variety of cellular antigens (demonstrated by the use of immunopathological techniques), molecular analyses of cell lines derived from these tumors, experimental production of PNETs and molecular genetic analyses.
Differences of opinion among surgeons, oncologists and radiotherapists are typically resolved by conducting cooperative studies of patients with these tumors who are diagnosed and treated at multiple centers.  相似文献   
43.
Corneal disease is the most common cause of bilateral blindness in the world. Visual loss in this condition is often due to changes in morphology and function of the corneal epithelial surface. Corneal disease-1 (corn1) and corn1(2J) are spontaneous mouse mutants that develop irregular thickening of the corneal epithelium, similar to that observed in human corneal surface disease. These autosomal-recessive mutations cause an increase in the rate of proliferation of the corneal epithelial cells. Here, we report that the phenotypes in both mutants are caused by mutations within the destrin gene (also known as actin-depolymerizing factor). By positional cloning, we identified a deletion encompassing the entire coding sequence of the destrin gene in corn1 mice, and a point mutation (Pro106Ser) in the coding sequence of destrin in corn1(2J) mice. In situ analysis showed that destrin is highly expressed in the corneal epithelium. Consistent with the cellular roles for destrin, an essential regulator of actin filament turnover that acts by severing and enhancing depolymerization of actin filament, we observed that the corn1 mutations increased the content of filamentous actin in corneal epithelial cells. Our results suggest an in vivo connection between remodeling of the actin cytoskeleton and the control of cell proliferation, and a new pathway through which an aberrant actin cytoskeleton can cause epithelial hyperproliferation.  相似文献   
44.
Low serum concentrations of the fourth component of complement (C4) are found in insulin dependent diabetes, and may be important in the aetiology of the disease. To ascertain whether function of C4 is also impaired both its haemolytic activity and its concentration were measured in 34 insulin dependent diabetics, 15 non-insulin dependent diabetics, 20 healthy subjects, and 12 pairs of monozygotic twins discordant for insulin dependent diabetes. C4 function was measured by a radial immune haemolytic assay, and C4 concentration by laser nephelometry. Both measurements were significantly lower in insulin dependent diabetics (C4 function: median 47%, range 4-100%; C4 concentration: 0.22 g/l, 0.10-0.38 g/l) than in non-insulin dependent diabetics (67%, 33-138%, p less than 0.01; 0.27 g/l, 0.16-0.50 g/l, p less than 0.02) and controls (74%, 33-138%, p less than 0.01; 0.27 g/l, 0.18-0.40 g/l, p less than 0.03). C4 function and concentration were lower in both diabetic (48%, 12-100%; 0.17 g/l, 0.08-0.31 g/l) and non-diabetic twins (47%, 12-100%; 0.17 g/l, 0.07-0.36 g/l) than controls (p less than 0.01; p less than 0.01). Thirteen (38%) of the insulin dependent diabetics had a reduction in either C4 function or concentration, but in only five were both features reduced. Values of function and concentration were strongly correlated in both diabetic and non-diabetic twins (r = 0.95, p less than 0.001; r = 0.92, p less than 0.001). These results show defects in C4 function and concentration in insulin dependent diabetes, which--being present in the non-diabetic co-twin of diabetics--may represent a genetic predisposition to the disease.  相似文献   
45.
Hemagglutination by polyoma virus has been shown to require sialic acid residues on cell surface oligosaccharides. This report presents evidence which suggests that adsorbtion of polyoma virus to erythrocytes is not due simply to a nonspecific electrostatic interaction with negatively charged sialic acids but rather requires the presence of specific sialyloligosaccharide structures. Newcastle disease virus (NDV) neuraminidase hydrolyzes sialic acids in the sequences NeuAcα2,3Gal and NeuAcα2,8NeuAc. Erythrocytes treated with NDV lost 40% of their surface sialic acid, retained full hemagglutination by certain influenza viruses which also bind sialyloligosaccharides, and yet were not agglutinated by polyoma virus. Erythrocytes treated with Vibrio cholerae neuraminidase, which removes virtually all sialic acid, were no longer agglutinated by influenza virus or polyoma virus. Selective replacement of sialic acid on V. cholerae neuraminidase-treated cells with purified β-galactoside α-2,3-sialytransferase in the sequence NeuAcα2, 3Gal completely restored hemagglutination by polyoma virus. In contrast, replacement of sialic acid by other sialyitransferases in the sequences NeuAcα2,6Gal or NeuAcα2,6GalNAc does not restore hemagglutination by polyoma virus.  相似文献   
46.
Mucosal leishmaniasis of the upper respiratory tract is usually associated with the visceral form or is found in immunosuppressed individuals. This report presents a case of isolated mucosal leishmaniasis in an immunocompetent patient, whose diagnosis mainly rested on histology and positive polymerase chain reaction result for Leishmania donovani in the laryngeal tissue. A 59-year-old man, who never lived outside Italy, showed a subglottic mucosal polypoid-like lesion. The typical morphological picture and positive polymerase chain reaction result for L donovani by DNA extracted from laryngeal biopsy specimens allowed the diagnosis of mucosal leishmaniasis. Specific amphotericin B therapy was started, resulting in clinical and endoscopic improvement. Increased knowledge about the histological and molecular tissue analysis of Leishmania enhances the diagnostic testing for mucosal leishmaniasis, as primary mucosal leishmaniasis may occur in both immunosuppresed and immunocompetent patients who travel to or reside in areas endemic for Leishmania.  相似文献   
47.
Infection of J774.1 murine macrophages by influenza A virus (IAV) induces two major responses, production of host defense molecules and death by apoptosis. We investigated whether induction of two cytotoxic compounds, tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO), directly caused IAV-induced apoptosis, and whether induction could be modulated by interferon-gamma (IFN-gamma) or the replication competence of the virus. Live IAV potently induced production of both TNF-alpha and NO, but UV inactivated virus was a poor inducer of both molecules. When cells were pre-treated with IFN-gamma, inactive IAV became as effective an inducer of NO, but not TNF-alpha, as live IAV. Amantadine, which antagonizes viral entry and replication, partly inhibited TNF-alpha and NO production in unprimed cells, but did not inhibit NO in IFN-gamma primed cells. IAV-induced cytotoxicity was not due to the induction of TNF-alpha or NO. Cells were insensitive to either TNF-alpha-containing supernatants or to recombinant TNF-alpha. Anti-TNF-alpha antibody did not protect cells from IAV-induced cell death, and anti-oxidants that inhibited TNF-alpha production also failed to increase cell survival. Inhibitors of NO production did not protect from IAV-induced cell death, either alone or in combination with superoxide dismutase (SOD). We conclude that, even though IAV was a potent inducer of TNF-alpha and NO in macrophages, IAV-induced apoptosis was not mediated directly by them. Importantly, viral replication was not required for the induction of TNF-alpha or NO, and the action of inactive IAV could be potentiated by IFN-gamma.  相似文献   
48.
The new 2017 diagnostic criteria for hypermobile Ehlers–Danlos Syndrome (hEDS) provide a framework for diagnosing hEDS but are more stringent than the previous Villefranche criteria. Our clinical experience at the GoodHope EDS clinic was that the 2017 criteria left many highly symptomatic patients without a diagnosis of hEDS. We conducted a retrospective cohort study to confirm our clinic experience and assess the accuracy of the 2017 diagnostic criteria for hEDS in patients who had a previous hEDS diagnosis based on the Villefranche criteria. Our study found that 15% (n = 20 of 131) of patients with a prior diagnosis of hEDS met the 2017 diagnostic criteria, and many of the traits used to distinguish hEDS were not significantly more frequent in patients who met 2017 criteria versus those who did not. In both groups objective systemic manifestations were found less frequently than subjective systemic manifestations. Beighton score (BS) as assessed by primary care practitioner was found to be higher than assessment by EDS practitioner in 81% (n = 74 of 91) of cases. Generalized joint hypermobility was confirmed in only 46% (n = 51 of 111) of patients who had a previous diagnosis of hEDS. Higher BS did not correlate with increased number of systemic manifestations in our cohort. Common comorbidities of hEDS were found with similar frequency in those who met 2017 criteria and those who did not. Based on our cohort, the 2017 hEDS diagnostic criteria require refinement to improve its diagnostic accuracy.  相似文献   
49.
The academic health center information environment is saturated with information of varying quality and overwhelming quantity. The most significant challenge is transforming data and information into knowledge. The University of Cincinnati Medical Center's (UCMC) focus is to develop an information architecture comprising data structures, Web services, and user interfaces that enable individuals to manage the information overload so that they can create new knowledge. UCMC has accomplished much of what is reported in this article with the help of a four-year Integrated Advanced Information Management Systems (IAIMS) operation grant awarded by the National Library of Medicine in 2003. In the UCMC vision for knowledge management, individuals have reliable, secure access to information that is filtered, organized, and highly relevant for specific tasks and personal needs. Current applications and tool sets will evolve to become the next generation knowledge management applications or smart digital services. When smart digital services are implemented, silo applications will disappear. A major focus of UCMC's IAIMS grant is research administration. Testing and building out existing and new research administration applications and digital services is underway. The authors review UCMC's progress and results in developing a software architecture, tools, and services for research administration. Included are sections on the evolution to full integration, the impact of the work at UCMC to date, lessons learned during this research and development process, and future plans and needs.  相似文献   
50.
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