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11.
Incomplete rescue of cystic fibrosis transmembrane conductance regulator deficient mice by the human CFTR cDNA 总被引:2,自引:2,他引:2
Rozmahel R; Gyomorey K; Plyte S; Nguyen V; Wilschanski M; Durie P; Bear CE; Tsui LC 《Human molecular genetics》1997,6(7):1153-1162
We have used a mouse model to study the ability of human CFTR to correct
the defect in mice deficient of the endogenous protein. In this model,
expression of the endogenous Cftr gene was disrupted and replaced with a
human CFTR cDNA by a gene targeted 'knock-in' event. Animals homozygous for
the gene replacement failed to show neither improved intestinal pathology
nor survival when compared to mice completely lacking CFTR. RNA analyses
showed that the human CFTR sequence was transcribed from the targeted
allele in the respiratory and intestinal epithelial cells. Furthermore, in
vivo potential difference measurements showed that basal CFTR chloride
channel activity was present in the apical membranes of both nasal and
rectal epithelial cells in all homozygous knock-in animals examined. Ussing
chamber studies showed, however, that the cAMP-mediated chloride channel
function was impaired in the intestinal tract among the majority of
homozygous knock-in animals. Hence, failure to correct the intestinal
pathology associated with loss of endogenous CFTR was related to
inefficient functional expression of the human protein in mice. These
results emphasize the need to understand the tissue- specific expression
and regulation of CFTR function when animal models are used in gene therapy
studies.
相似文献
12.
Human MSH2 binds to trinucleotide repeat DNA structures associated with neurodegenerative diseases 总被引:5,自引:5,他引:5
The expansion of trinucleotide repeat sequences is associated with several
neurodegenerative diseases. The mechanism of this expansion is unknown but
may involve slipped-strand structures where adjacent rather than perfect
complementary sequences of a trinucleotide repeat become paired. Here, we
have studied the interaction of the human mismatch repair protein MSH2 with
slipped-strand structures formed from a triplet repeat sequence in order to
address the possible role of MSH2 in trinucleotide expansion. Genomic
clones of the myotonic dystrophy locus containing disease-relevant lengths
of (CTG)n x (CAG)n triplet repeats were examined. We have constructed two
types of slipped-strand structures by annealing complementary strands of
DNA containing: (i) equal numbers of trinucleotide repeats (homoduplex
slipped structures or S-DNA) or (ii) different numbers of repeats
(heteroduplex slipped intermediates or SI-DNA). SI-DNAs having an excess of
either CTG or CAG repeats were structurally distinct and could be separated
electrophoretically and studied individually. Using a band-shift assay, the
MSH2 was shown to bind to both S-DNA and SI-DNA in a structure- specific
manner. The affinity of MSH2 increased with the length of the repeat
sequence. Furthermore, MSH2 bound preferentially to looped-out CAG repeat
sequences, implicating a strand asymmetry in MSH2 recognition. Our results
are consistent with the idea that MSH2 may participate in trinucleotide
repeat expansion via its role in repair and/or recombination.
相似文献
13.
An improved colorimetric assay for cell proliferation and viability utilizing the tetrazolium salt XTT 总被引:43,自引:0,他引:43
N W Roehm G H Rodgers S M Hatfield A L Glasebrook 《Journal of immunological methods》1991,142(2):257-265
A new tetrazolium salt XTT, sodium 3'-[1-[(phenylamino)-carbonyl]-3,4-tetrazolium]-bis(4-methoxy-6- nitro)benzene-sulfonic acid hydrate, was evaluated for use in a colorimetric assay for cell viability and proliferation by normal activated T cells and several cytokine dependent cell lines. Cleavage of XTT by dehydrogenase enzymes of metabolically active cells yields a highly colored formazan product which is water soluble. This feature obviates the need for formazan crystal solubilization prior to absorbance measurements, as required when using other tetrazolium salts such as MTT. Bioreduction of XTT by all the murine cells examined was not particularly efficient, but could be potentiated by addition of electron coupling agents such as phenazine methosulfate (PMS) or menadione (MEN). Optimal concentrations of PMS or MEN were determined for the metabolism of XTT by the T cell lines HT-2 and 11.6, NFS-60 a myeloid leukemia, MC/9 a mast cell line and mitogen activated splenic T cells. When used in combination with PMS, each of these cells generated higher formazan absorbance values with XTT than were observed with MTT. Thus the use of XTT in colorimetric proliferation assays offer significant advantages over MTT, resulting from reduced assay time and sample handling, while offering equivalent sensitivity. 相似文献
14.
Russell EJ; Geremia GK; Johnson CE; Huckman MS; Ramsey RG; Washburn-Bleck J; Turner DA; Norusis M 《Radiology》1987,165(3):609-617
Sixteen patients with suspected cerebral metastases were studied with magnetic resonance (MR) imaging before and after the intravenous administration of 0.1 mmol/kg of gadolinium diethylenetriaminepenta-acetic acid. The images were interpreted blindly by two neuroradiologists; all clinical, radiologic (computed tomographic and MR imaging), and pathologic data were reviewed to arrive at a final "best diagnosis," which was then compared with the prior blinded interpretations. Of seven patients found to have multiple metastases, six (86%) had at least one tumor nodule depicted by postinfusion MR imaging that was missed by one or both observers on review of preinfusion images alone. Lesions missed on preinfusion studies were usually small nodules hidden by or not detected next to regions of high-signal edema thought to be related to the adjacent tumor nodule. The authors believe that contrast enhancement improves detection of metastatic foci with MR imaging and that the findings indicate broader implications for the detection of multiple lesions from other causes. 相似文献
15.
Rao VM; Dalinka MK; Mitchell DG; Spritzer CE; Kaplan F; August CS; Axel L; Kressel HY 《Radiology》1986,161(1):217-220
Four patients with proved osteopetrosis (three with the infantile malignant form and one with the benign form) were examined with magnetic resonance imaging at 1.5 T. All patients were studied in the coronal and sagittal planes using both short and long repetition time/echo time sequences. The infantile malignant form was characterized by a complete lack of signal from the marrow alternating with a signal intensity equivalent to that of the intervertebral disks, resulting in a "stepladder" appearance. In the benign form or after successful marrow transplantation in the infantile malignant form, intermediate or high signal intensity in the vertebrae was noted, suggesting the presence of some marrow elements. 相似文献
16.
Jejunoileal arteriovenous malformation: localization for resection by segmental bowel staining techniques. 总被引:1,自引:0,他引:1
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Arteriovenous malformations, submucosal vascular lakes, of the jejunum and ileum which cause chronic gastrointestinal bleeding and anemia are easily identified before operation by selective arteriography but difficult at operation owing to lack of physical signs. This report is concerned with a patient who had such a lesion located in the proximal jejunum. The involved segment was easily identified at operation by injection of Indigo Carmine solution during operation into the involved jejunal artery subselectively catheterized immediately prior to operation. The duration of jejunal staining before resection was 45 minutes in this case and varied from 35 to 55 minutes in five other patients who had right colectomy for carcinoma, providing the opportunity to inject accurately in a conveniently located radiology suite before operation. Safe, convenient, longer periods of staining which could be performed at the time of original diagnosis were demonstrated in dog experiments using "biologic" colloidal carbon in which the bowel segment was well stained at the time of sacrifice five days after injection. There were no gross or microscopic signs of injury to bowel. 相似文献
17.
目的 研究Ewing’s肉瘤细胞系 (RM 82 )X 射线外照射后肿瘤坏死因子 (TNF α)和转化生长因子 (TGF β)mRNA表达水平的变化 ,探讨X 射线诱导内源性TNF α和TGF β产生的可能性及意义。 方法 应用实时荧光RT PCR ,检测接受不同剂量X 线照射 (2Gy ,5Gy ,10Gy ,2 0Gy ,30Gy ,4 0Gy)和受照后不同时间 (1h ,3h ,6h ,12h ,2 4h ,4 8h ,72h)。TNF α和TGF βmRNA表达水平的变化。 结果 RM 82细胞TNF αmRNA表达水平较外照射前显著升高。一方面受照后TNF αmRNA表达逐渐升高 ,照射剂量达 4 0Gy时TNF αmRNA表达水平达高峰 ,为正常对照组的 10 8倍 ;另一方面 ,照射后 3h后TNF αmRNA表达逐渐升高 ,6h达高峰 ,为正常对照组的 18倍。相反 ,TGF βmRNA表达水平X 射线照射前后无显著变化。结论 Ewing’s肉瘤细胞系 (RM 82 )接受X 线照射后TNF αmRNA表达明显升高 ,且呈现时间、剂量依赖性。放射治疗可诱导Ewing’s肉瘤细胞系 (RM 82... 相似文献
18.
Higher fat and energy intakes confer a survival advantage in cystic fibrosis (CF). There is a need to develop effective nutrition programmes that ensure optimal energy intake in CF.
A cross-sectional measurement of clinical characteristics and energy and fat intakes in patients attending the CF outpatients clinic of the John Hunter Hospital, Newcastle was undertaken. Twenty-nine subjects, mean age 12 years (range 4.3–20.2), completed weighed food records to determine the contribution of fat to the percentage of the recommended energy intake obtained and to document use of pancreatic enzyme replacement therapy.
Diets with a high percentage of energy derived from fat did not guarantee that individuals with CF met their energy requirements. Subjects with total fat intakes of 100 g per day or greater, however, achieved in excess of 110% recommended daily intake (RDI) for energy. Up to 47% of subjects consumed more pancreatic enzyme replacement capsules than shown to give maximum effectiveness.
Setting a 100 g daily fat target is a realistic way of ensuring high energy intakes in CF. Fat ready reckoners would identify the fat content of food and prescribe specific numbers of pancreatic enzyme replacement capsules to be consumed with each meal or food item. 相似文献
Methodology:
A cross-sectional measurement of clinical characteristics and energy and fat intakes in patients attending the CF outpatients clinic of the John Hunter Hospital, Newcastle was undertaken. Twenty-nine subjects, mean age 12 years (range 4.3–20.2), completed weighed food records to determine the contribution of fat to the percentage of the recommended energy intake obtained and to document use of pancreatic enzyme replacement therapy.
Results:
Diets with a high percentage of energy derived from fat did not guarantee that individuals with CF met their energy requirements. Subjects with total fat intakes of 100 g per day or greater, however, achieved in excess of 110% recommended daily intake (RDI) for energy. Up to 47% of subjects consumed more pancreatic enzyme replacement capsules than shown to give maximum effectiveness.
Conclusion:
Setting a 100 g daily fat target is a realistic way of ensuring high energy intakes in CF. Fat ready reckoners would identify the fat content of food and prescribe specific numbers of pancreatic enzyme replacement capsules to be consumed with each meal or food item. 相似文献
19.
de Haas M; Kerst JM; van der Schoot CE; Calafat J; Hack CE; Nuijens JH; Roos D; van Oers RH; von dem Borne AE 《Blood》1994,84(11):3885-3894
In four healthy volunteers, we analyzed in detail the immediate in vivo effects on circulating neutrophils of subcutaneous administration of 300 micrograms of granulocyte colony-stimulating factor (G-CSF). Neutrophil activation was assessed by measurement of degranulation. Mobilization of secretory vesicles was shown by a decrease in leukocyte alkaline phosphatase content of the circulating neutrophils. Furthermore, shortly postinjection, Fc gamma RIII was found to be upregulated from an intracellular pool that we identified by immunoelectron microscopy as secretory vesicles. Intravascular release of specific granules was shown by increased plasma levels of lactoferrin and by upregulation of the expression of CD66b and CD11b on circulating neutrophils. Moreover, measurement of fourfold elevated plasma levels of elastase, bound to its physiologic inhibitor alpha 1- antitrypsin, indicated mobilization of azurophil granules. However, no expression of CD63, a marker of azurophil granules, was observed on circulating neutrophils. G-CSF--induced mobilization of secretory vesicles and specific granules could be mimicked in whole blood cultures in vitro, in contrast to release of azurophil granules. Therefore, we postulate that the most activated neutrophils leave the circulation, as observed shortly postinjection, and undergo subsequent stimulation in the endothelial microenvironment, resulting in mobilization of azurophil granules. Our data demonstrate that G-CSF should be regarded as a potent immediate activator of neutrophils in vivo. 相似文献
20.
CE Faggons C Mabedi CG Shores S Gopal 《Malawi medical journal : the journal of Medical Association of Malawi》2015,27(3):79-87