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91.
Vankeerberghen A; Wei L; Jaspers M; Cassiman JJ; Nilius B; Cuppens H 《Human molecular genetics》1998,7(11):1761-1769
In order to gain a better insight into the structure and function of the
regulatory domain (RD) of the cystic fibrosis transmembrane conductance
regulator (CFTR) protein, 19 RD missense mutations that had been identified
in patients were functionally characterized. Nine of these (I601F, L610S,
A613T, D614G, I618T, L619S, H620P, G628R and L633P) resulted in aberrant
processing. No or a very small number of functional CFTR proteins will
therefore appear at the cell membrane in cells expressing these mutants.
These mutations were clustered in the N- terminal part of the RD,
suggesting that this subdomain has a folding pattern that is very sensitive
to amino acid changes. Mutations that caused no aberrant processing were
further characterized at the electrophysiological level. First, they were
studied at the whole cell level in Xenopus laevis oocytes. Mutants that
induced a whole cell current that was significantly different from
wild-type CFTR were subsequently analysed at the single channel level in
COS1 cells transiently expressing the different mutant and wild-type
proteins. Three mutant chloride channels, G622D, R792G and E822K CFTR, were
characterized by significantly lower intrinsic chloride channel activities
compared with wild-type CFTR. Two mutations, H620Q and A800G, resulted in
increased intrinsic chloride transport activities. Finally, T665S and E826K
CFTR had single channel properties not significantly different from
wild-type CFTR.
相似文献
92.
Shimon Harrus Trevor Waner Itzhak Aizenberg Janet E. Foley Amy M. Poland Hylton Bark 《Journal of clinical microbiology》1998,36(1):73-76
In order to determine whether dogs in the subclinical phase of canine monocytic ehrlichiosis (CME) are carriers of Ehrlichia canis and to determine the significance of persistent indirect immunofluorescent anti-E. canis antibody titers during this phase, PCR was performed with blood, bone marrow, and splenic aspirates collected 34 months postinoculation from six clinically healthy beagle dogs experimentally infected with E. canis. At least one of the three samples (spleen, bone marrow, and blood) from four of the six dogs was PCR positive. The spleens of all four of these dogs were PCR positive, and the bone marrow and blood of two of the four dogs were PCR positive. Indirect immunofluorescent-antibody titers increased progressively during the first 5 months postinfection, remained high for an additional period of more than 11 months, and declined thereafter, suggesting that the dogs were recovering from the disease. Five of the dogs remained seropositive 34 months postinfection. The data obtained in this study demonstrate for the first time that clinically healthy dogs in the subclinical phase of CME are carriers of the rickettsia. It was shown that dogs can harbor E. canis for years without developing the chronic clinical disease and that dogs can eliminate the parasite and recover from CME without medical treatment. Our findings suggest that the spleen is the organ most likely to harbor E. canis parasites during the subclinical phase and the last organ to accommodate the parasite before elimination. It was concluded that PCR of DNA extracted from splenic aspirates is a reliable method for determining the carrier state of CME. 相似文献
93.
Different cerebellar regions participate in balance control and voluntary limb coordination, both of which might be important for normal bipedal walking. We wanted to determine the relative contributions of balance versus leg-coordination deficits to cerebellar gait ataxia in humans. We studied 20 subjects with cerebellar damage and 20 control subjects performing three tasks: a lateral weight-shifting task to measure balance, a visually guided stepping task to measure leg- coordination, and walking. We recorded three-dimensional joint position data during all tasks and center of pressure coordinates during weight-shifting. Each cerebellar subject was categorized as having no detectable deficits, a balance deficit only, a leg-placement deficit only, or both deficits. We then determined the walking abnormalities associated with each of these categories. Five of 10 measures of gait ataxia were abnormal in cerebellar subjects with a balance deficit, but only 1 was abnormal in cerebellar subjects with a leg-placement deficit. Furthermore, subjects with a balance deficit performed worse than subjects with a leg-placement deficit on 9 of the 10 gait measures. Finally, performance on the balance task, but not the leg-placement task, explained a significant proportion of the variance in walking speed for the entire cerebellar group. We conclude that balance deficits are more closely related to cerebellar gait ataxia than leg-placement deficits. Our findings are consistent with animal literature, which has suggested that cerebellar control of balance and gait are interrelated, and dissociable from cerebellar control of voluntary, visually guided limb movements. 相似文献
94.
Theodore C. Iancu Hanna Shiloh Kishor B. Raja Robert J. Simpson Timothy J. Peters Daniel P. Perl Amy Hsu Paul F. Good 《The Journal of pathology》1995,177(1):83-94
Homozygote hypotransferrinaemic mice (hpx/hpx) have cytopathological features similar to those of human congenital atransferrinaemia, genetic haemochromatosis, and neonatal haemochromatosis. These conditions all have in common high levels of cytotoxic non-transferrin-bound serum iron. This study describes the ultrastructural features of iron overload in liver, pancreas, heart, and small intestine of 2- and 12-month-old hypotransferrinaemic mice. Electron microscopic studies of unstained sections showed early parenchymal cell siderosis, with accumulation of numerous ferritin particles and clusters in the cytosol, as well as ferritin and haemosiderin in lysosomes (siderosomes). In the 12-month-old animals, iron was also found in Kupffer cells and macrophages in other tissues. In addition, there were conspicuous iron-containing compounds in the bile canaliculi, and marked iron deposition in the pancreas and heart. Laser microprobe mass analysis (LAMMA) enabled localization and relative quantitation of iron deposition in subcellular compartments providing in situ documentation of iron accumulation in siderosomes and contributed in assessing total cytosolic iron in various cell types. Moreover, it demonstrated the importance and magnitude of the biliary route for iron excretion in these animals. 相似文献
95.
Johanna L. Schmidt MPH MGC CGC Amy Pizzino MS CGC Jessica Nicholl MS CGC Allison Foley MMSc CGC Yue Wang PhD FACMG Jill A. Rosenfeld MS CGC Lindsey Mighion MS CGC Lora Bean PhD Cristina da Silva MS Megan T. Cho MS CGC Rebecca Truty PhD John Garcia PhD Virginia Speare PhD Kirsten Blanco BS Zoe Powis MS CGC Grace M. Hobson PhD Susan Kirwin BS Bryan Krock PhD FACMG Hane Lee PhD Joshua L. Deignan PhD Maggie A. Westemeyer MS CGC Ryan L. Subaran PhD Isabelle Thiffault PhD FABMGG Ellen A. Tsai PhD Terry Fang PhD Guy Helman BS Adeline Vanderver MD 《American journal of medical genetics. Part A》2020,182(8):1906-1912
Leukodystrophies are a heterogeneous group of heritable disorders characterized by abnormal brain white matter signal on magnetic resonance imaging (MRI) and primary involvement of the cellular components of myelin. Previous estimates suggest the incidence of leukodystrophies as a whole to be 1 in 7,000 individuals, however the frequency of specific diagnoses relative to others has not been described. Next generation sequencing approaches offer the opportunity to redefine our understanding of the relative frequency of different leukodystrophies. We assessed the relative frequency of all 30 leukodystrophies (associated with 55 genes) in more than 49,000 exomes. We identified a relatively high frequency of disorders previously thought of as very rare, including Aicardi Goutières Syndrome, TUBB4A‐related leukodystrophy, Peroxisomal biogenesis disorders, POLR3‐related Leukodystrophy, Vanishing White Matter, and Pelizaeus‐Merzbacher Disease. Despite the relative frequency of these conditions, carrier‐screening laboratories regularly test only 20 of the 55 leukodystrophy‐related genes, and do not test at all, or test only one or a few, genes for some of the higher frequency disorders. Relative frequency of leukodystrophies previously considered very rare suggests these disorders may benefit from expanded carrier screening. 相似文献
96.
K. Taylor Wild Amy C. Goldstein Colleen Muraresku Rebecca D. Ganetzky 《American journal of medical genetics. Part A》2020,182(2):365-373
Pearson syndrome (PS) is a multisystem mitochondrial respiratory chain disorder typically characterized by sideroblastic anemia and exocrine pancreatic insufficiency. PS is caused by a single large‐scale mitochondrial DNA (mtDNA) deletion. PS classically presents in the first year of life and may be fatal in infancy. Children who survive PS may progress to develop Kearns–Sayre syndrome later in life. The full phenotypic spectrum and prognosis of the condition continue to evolve. Here we report five new patients with PS with unique clinical presentations, including four patients with onset later than previously reported in the literature, and one patient with prenatal onset of symptoms. The timing and unique features of these presentations support an expanded phenotypic spectrum of single large‐scale mtDNA deletion syndromes (SLSMDS) and reinforce the importance of including SLSMDS in the differential for children with complex multisystem presentations. 相似文献
97.
Kummrow M Meli ML Haessig M Goenczi E Poland A Pedersen NC Hofmann-Lehmann R Lutz H 《Clinical and diagnostic laboratory immunology》2005,12(10):1209-1215
To determine the prevalence of antibodies to feline coronavirus (FCoV) serotypes 1 and 2 in Switzerland and their association with different disease manifestations, a serological study based on immunofluorescence tests was conducted with Swiss field cats using transmissible gastroenteritis virus (TGEV), FCoV type 1 and FCoV type 2 as antigens. A total of 639 serum samples collected in the context of different studies from naturally infected cats were tested. The current study revealed that, with an apparent prevalence of 83%, FCoV serotype 1 is the most prevalent serotype in Switzerland. FCoV type 1 viruses induced higher antibody titers than FCoV type 2, and were more frequently associated with clinical signs and/or feline infectious peritonitis. The antibody development in seven cats experimentally infected with FCoV type 1 revealed that, with progressing duration of infection, antibodies to FCoV type 1 significantly increased over those to FCoV type 2. There was a significant relationship between antibody titers against TGEV, FCoV 1, and FCoV 2 and TGEV antigen detected the highest proportion of seropositive cats. We conclude that a vaccine against FCoV should be based on FCoV type 1-related antigens and that for serodiagnosis of FCoV infection TGEV should be used to attain the highest diagnostic efficiency. When serology is used in addition to clinical signs, hematology, and clinical chemistry results as an aid to diagnose clinical FIP, TGEV shows a diagnostic efficiency equal to that of a FCoV antigen. 相似文献
98.
99.
100.
In Vivo Complementation of ureB Restores the Ability of Helicobacter pylori To Colonize 总被引:4,自引:0,他引:4 下载免费PDF全文
Kathryn A. Eaton Joanne V. Gilbert Elizabeth A. Joyce Amy E. Wanken Tracy Thevenot Patrick Baker Andrew Plaut Andrew Wright 《Infection and immunity》2002,70(2):771-778
The objective of this study was to determine (i) if complementation of ureB-negative Helicobacter pylori restores colonization and (ii) if urease is a useful reporter for promoter activity in vivo. Strains used were M6, M6DeltaureB, and 10 recombinant derivatives of M6 or M6DeltaureB in which urease expression was under the control of different H. pylori promoters. Mice were orally inoculated with either the wild type or one of the mutant strains, and colonization, in vivo urease activity, and extent of gastritis were determined. Of eight M6DeltaureB recombinants tested, four colonized mice. Of those, three had the highest in vitro urease activity of any of the recombinants, significantly different from that of the noncolonizing mutants. The fourth colonizing recombinant, with ureB under control of the cag-15 promoter, had in vitro urease activity which did not differ significantly from the noncolonizing strains. In vivo, urease activities of the four colonizing transformants and the wild-type control were indistinguishable. There were no differences in gastritis or epithelial lesions between mice infected with M6 and those infected with the transformants. These results demonstrate that recovery of urease activity can restore colonizing ability to urease-negative H. pylori. They also suggest that cag-15 is upregulated in vivo, as was previously suggested by demonstrating that it is upregulated upon contact with epithelial cells. Finally, our results suggest that total urease activity and colonization density do not contribute to gastritis due to H. pylori. 相似文献