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1.
The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed. 相似文献
2.
3.
A high-resolution method for amino acid analysis of physiological fluids containing mixed disulfides 总被引:2,自引:0,他引:2
In this paper we report a high-resolution method and special buffers for the analysis for 45 common amino acids and related compounds and seven less-common components occasionally found in physiological fluids. Careful optimization of the chromatographic protocol resolves cysteine-penicillamine mixed disulfide, penicillamine disulfide, and dihydroxyphenylalanine from cystine and methionine; cysteine-homocysteine mixed disulfide is eluted between tyrosine and phenylalanine. Argininosuccinic acid is eluted before ethanolamine; glycerophosphoethanolamine is separated from taurine; glucosaminic acid is eluted between urea and aspartic acid. A Beckman Instruments System 6300 Amino Acid Analyzer was used. System performance is examined in terms of coefficient of variation (CV) over the concentration range of 1.0-5.0 nmol/50 microL; average CV for all components is better than 1.5%. Method performance is assessed through the analysis of normal and abnormal urine and plasma specimens. 相似文献
4.
Hausegger KA; Cragg AH; Lammer J; Lafer M; Fluckiger F; Klein GE; Sternthal MH; Pilger E 《Radiology》1994,190(1):199
5.
Serum ionic fluoride levels in haemodialysis and continuous ambulatory peritoneal dialysis patients 总被引:1,自引:1,他引:0
al-Wakeel JS; Mitwalli AH; Huraib S; al-Mohaya S; Abu-Aisha H; Chaudhary AR; al-Majed SA; Memon N 《Nephrology, dialysis, transplantation》1997,12(7):1420-1424
High serum fluoride (F-) in patients with chronic renal failure (CRF) and
end-stage renal disease (ESRD) is associated with risk of renal
osteodystrophy and other bone changes. This study was done to determine F-
in normal healthy controls and patients with ESRD on haemodialysis (HD) or
peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females)
and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in
the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l)
of F- content in drinking water. Control subjects showed a mean serum F-
concentration of 1.08 +/- 0.350 microM/l. Males in control group showed
slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than
females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F-
concentration did not correlate significantly with age and sex among
control subjects, whereas such correlation was observed in patients with
ESRD on dialysis. Mean serum F- concentration was significantly higher in
patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal
controls. When grouped according to sex, the mean serum F- concentration in
males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than
females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped
according to age, it was observed that F- concentration was significantly
higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with
age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated
with age and sex, being higher in males and above 20 years. Despite
appreciable clearance of F- (39-90%) across the peritoneum, patients on
CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs
2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their
serum F- concentration above 3.0 microM/l, posing the risk of renal
osteodystrophy.
相似文献
6.
Focal liver lesions: characterization with triphasic spiral CT 总被引:15,自引:1,他引:14
7.
Metabolic adaptation of the chick embryo to chronic hypoxia 总被引:1,自引:0,他引:1
8.
The CTLA-4 gene region of chromosome 2q33 is linked to, and associated with, type 1 diabetes. Belgian Diabetes Registry 总被引:8,自引:1,他引:8
Nistico L; Buzzetti R; Pritchard LE; Van der Auwera B; Giovannini C; Bosi E; Larrad MT; Rios MS; Chow CC; Cockram CS; Jacobs K; Mijovic C; Bain SC; Barnett AH; Vandewalle CL; Schuit F; Gorus FK; Tosi R; Pozzilli P; Todd JA 《Human molecular genetics》1996,5(7):1075-1080
Susceptibility to autoimmune insulin-dependent (type 1) diabetes mellitus
is determined by a combination of environmental and genetic factors, which
include variation in MHC genes on chromosome 6p21 (IDDM1) and the insulin
gene on chromosome 11p15 (IDDM2). However, linkage to IDDM1 and IDDM2
cannot explain the clustering of type 1 diabetes in families, and a role
for other genes is inferred. In the present report we describe linkage and
association of type 1 diabetes to the CTLA-4 gene (cytotoxic T lymphocyte
associated-4) on chromosome 2q33 (designated IDDM12). CTLA-4 is a strong
candidate gene for T cell- mediated autoimmune disease because it encodes a
T cell receptor that mediates T cell apoptosis and is a vital negative
regulator of T cell activation. In addition, we provide supporting evidence
that CTLA-4 is associated with susceptibility to Graves' disease, another
organ- specific autoimmune disease.
相似文献
9.
10.
MDR1 P-glycoprotein is expressed by endothelial cells of newly formed capillaries in human gliomas but is not expressed in the neovasculature of other primary tumors. 总被引:7,自引:0,他引:7 下载免费PDF全文
K. Tth M. M. Vaughan N. S. Peress H. K. Slocum Y. M. Rustum 《The American journal of pathology》1996,149(3):853-858
The expression of human MDR1 P-glycoprotein (Pgp) in the capillary endothelial cells of the central nervous system has been demonstrated. The brain capillary endothelial cells maintain the structure and function of the blood-brain barrier. Recently, the human MDR1 Pgp (and its mouse homologue MDR1a Pgp) has been shown to function as an important part of this barrier, pumping out xenobiotics from endothelial cells into the lumen of capillaries resulting in the protection of the brain parenchyma. To examine whether the endothelial cells of the newly formed capillaries during neoangiogenesis within malignant human brain tumors express MDR1 Pgp, 35 adult surgical brain tumor specimens (29 gliomas and 6 tumors metastatic to the brain) were obtained from previously untreated patients and studied by a new immunohistochemical sandwich method developed in our laboratory using the JSB-1 monoclonal antibody. JSB-1 is specific for the Pgp product of the human MDR1 (and not MDR3) gene. This sensitive method allows the detection of Pgp in capillary endothelial cells of normal brain in conventional paraffin sections after formalin fixation. The endothelial cells of the newly formed capillaries in 25 of 29 gliomas (86%) and 3 of 6 metastatic tumors, immunostained positive for MDR1 Pgp. The tumor cells in 7 of 35 cases were also positive for Pgp. In the 35 brain tumor cases investigated, the endothelial cells were Pgp positive in the tumor-brain border and in the brain further from the tumor. Capillary endothelial cells of neovasculature in 137 malignant tumors (non-brain) obtained from previously untreated patients showed no MDR1 Pgp expression. These results demonstrated that MDR1 Pgp is expressed not only in the capillaries of normal brain but also in the majority of the newly formed capillaries of brain tumors. Multidrug resistance of brain tumors may result not only from the expression of resistance markers in neoplastic cells but also from the MDR1 Pgp expression in endothelial cells of tumor capillaries. Pgp in this special localization can exclude chemotherapeutic agents from tumor cells that are located around the capillaries. The therapeutic benefit and selectivity of chemotherapeutic agents in combination with a Pgp-reversing agent should be evaluated. 相似文献