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951.
Molecular techniques have recently revealed that there are several immunologically distinct Ro/SS-A antigens. Three genes encoding putative Ro/SS-A protein antigens with calculated masses of 46, 52, and 60 kD have been isolated. The encoded amino acid sequence of each is quite dissimilar. The 46-kD antigen is calreticulin (CR), a highly conserved calcium-binding protein that resides predominately in the endoplasmic reticulum where it may be involved in protein assembly. Although CR has recently been confirmed to be a new human rheumatic disease-associated autoantigen, its relationship to the other components of the Ro/SS-A ribonucleoprotein has become somewhat controversial owing predominately to the fact that recombinant forms of calreticulin have not displayed the same pattern of autoantibody reactivity possessed by the native form of this protein. The 52-kD antigen most likely resides in the nucleus and may be involved in the regulation of gene expression. The cellular location and function of the 60-kD antigen is uncertain but studies indicate that it is a RNA-binding protein. The 46- and 60-kD antigens share homology with foreign polypeptides, suggesting that an immune response initially directed against a foreign protein may give rise to the autoimmune response directed at cross-reacting self proteins. 相似文献
952.
A system has been developed that can generate recombinant baculovirus expression vectors at frequencies approaching 100%. This system provides a selection for recombinant viruses by using the essential gene downstream of the Autographa californica nuclear polyhedrosis virus (AcMNPV) polyhedrin expression locus. Two AcMNPV derivatives were constructed in which the expression locus and part of the downstream gene are flanked by restriction sites. The parental viruses are viable; however, restriction of the viral DNAs removes an essential piece of the viral genome. Transfer vectors carry a copy of the missing sequences downstream from the site into which foreign genes are inserted for expression; hence, recombination between a transfer vector and the restricted viral DNA can restore the integrity of the essential gene. Such recombination events also transfer any foreign gene present in the expression locus of the transfer vector to the viral genome. Recombinant viruses therefore have a selective advantage over nonrecombinant viral DNAs. Consequently, a high proportion of the viruses obtained by co-transfecting transfer vector DNA and restricted viral DNA of one of these new viruses expresses the target gene from the transfer vector. This system greatly reduces the time needed to make recombinant baculovirus expression vectors. 相似文献
953.
PURPOSE: To evaluate the clinical utility and morphologic accuracy of gadolinium-enhanced excretory magnetic resonance (MR) urography after low-dose diuretic injection and to correlate the results with those of conventional urography. MATERIALS AND METHODS: In 71 patients with urologic symptoms, excretory MR urography was performed after intravenous injection of 5-10 mg furosemide and, 30-60 seconds later, 0.1 mmol of gadopentetate dimeglumine per kilogram of body weight. The MR urograms were interpreted by three radiologists, who were blinded to the clinical outcome, and subsequently compared with conventional urograms. RESULTS: Injection of furosemide before contrast material led to rapid, uniform gadolinium distribution inside a sufficiently distended collecting system such that there was no excessive concentration of gadolinium in the urine. In patients with normal or moderately reduced excretory function, this effect allowed complete visualization of the urinary tract within 5-20 minutes of contrast material injection while minimizing gadolinium-related endoluminal T2* effects. The clinical course helped verify almost all MR urographic results. The MR urographic technique was significantly superior to conventional urography in the assessment of the ureters and bladder (P < .0001). Delineation of small caliceal abnormalities is still problematic. The best depiction of the pelvicaliceal system was obtained with fat-suppressed MR imaging, although it was still slightly inferior to conventional urography (P < .05). CONCLUSION: Gadolinium-enhanced excretory MR urography performed after low-dose diuretic injection is a promising and accurate alternative to conventional excretory urography for imaging the morphology of the urinary tract. 相似文献
954.
PURPOSE: Choice of efficacious clinical management of symptomatic renal calculi can be facilitated by ascertaining the precise chemical composition of the calculus. Spiral computerized tomography (CT) is becoming a frequently used radiographic examination to establish the diagnosis and severity of calculus disease. Our objective for this study was to determine the precision of spiral CT in identifying the chemical composition of 6 different types of urinary calculi with region of interest measurements using spiral CT. MATERIALS AND METHODS: A total of 102 chemically pure stones were separated into 6 groups. The stones along with phantoms containing butter (fat) and jello (water) were mounted vertically in the scanner gantry. Then 1 mm. thickness scanning was performed with a high speed scanner at the 2 energy levels of 80 and 120 kV. The determination of the chemical composition was performed using the absolute CT value measured at 120 kV. and the dual kilovolt CT values measured at 80 and 120 kV. Hounsfield unit at 80 kV.-Hounsfield unit at 120 kV.). RESULTS: The absolute CT value measured at 120 kV. was able to identify precisely the chemical composition of uric acid, struvite and calcium oxalate stones. It was imprecise in differentiating calcium oxalate from brushite stone and struvite from cystine stone. However, dual kilovolt CT value was able to differentiate these latter stones with statistical significance (p < 0.03). Uric acid stones were easily differentiated from all other stones using the absolute CT value. CONCLUSIONS: This study demonstrates that the chemical composition of urinary calculi can be accurately determined by CT scanning in an in vitro setting. 相似文献
955.
PC Cook S Jiang JL Chertkov Y Fan RD Levere NG Abraham 《Canadian Metallurgical Quarterly》1996,96(2):57-63
PURPOSE: To explore relationships between pregnant women's childhood experiences with discipline and 1) prenatal plans for disciplining own child and 2) later maternal-infant interactions DESIGN: Prospective correlation study. SETTING: Prenatal clinics and home visits PARTICIPANTS: Low-income pregnant women (N = 205) with a mean educational level of 12 years MAIN OUTCOME MEASURES: Adapted Ways of Handling Irritating Behaviors (Mother and You) Scales, NCAST Teaching Scale, Home Observation for Measurement of the Environment Scale RESULTS: Correlations between childhood experiences with discipline and 1) plans for later discipline strategies with own child and 2) infant components of maternal-infant interactions, including clarity of cues and responsiveness to the mother CONCLUSIONS: Prenatal assessment for childhood experiences with discipline may uncover factors associated with a break in the trajectory for optimal maternal-child interactions described by Barnard's theoretical framework. 相似文献
956.
OBJECTIVES: To evaluate the effect of aspirin (ASA) therapy on postoperative blood loss, transfusion requirements, reoperation for bleeding, duration of stay in the intensive care unit and in the hospital in a selected population undergoing a first coronary artery bypass grafting (CABG) surgery. DESIGN: Prospective observational study in consecutive patients during a 3-month period. SETTING: A teaching cardiothoracic center. PARTICIPANTS: Two hundred forty consecutive patients undergoing elective coronary artery bypass grafting surgery for the first time. INTERVENTIONS: Two hundred forty consecutive patients admitted for a first CABG the day before surgery were visited. patients with an abnormal routine coagulation screen or taking drugs that might have affected their coagulation mechanisms were prospectively excluded (n = 96). The date of the last dose of ASA was recorded in the 144 remaining patients, and data were acquired prospectively. MEASUREMENTS AND MAIN RESULTS: Total mediastinal blood drainage, blood products usage, reopening, and duration of intensive care unit and hospital stay were recorded. Patients were grouped by days free of ASA. There were no significant differences detected between groups. CONCLUSIONS: In patients undergoing a first CABG and with no known factors affecting their coagulation, ASA therapy did not appear to increase blood loss, reopening for bleeding, or blood products usage requirements during the hospital stay. ASA therapy did not influence the duration of stay in intensive care or in the hospital. 相似文献
957.
The segmental dynamics of solid-state poly(methylphenylsilane) were probed with deuterium solid-echo and two-dimensional exchange (2D-X) NMR via a methyl-d3 label. Between 25 and 50 degreesC, the spectra indicated that the polymer consisted of two fractions-a fast fraction with correlation times (tauc) below 10(-5) s and one with tauc's above 10 s. Above 50 degreesC, motion with tauc's around 10(-3) s was also detected. A minimization routine was developed to fit the 2D-X spectra to a model of isotropic rotational diffusion with a distribution of tauc's. The best fits were obtained with trimodal stretched-exponential distributions. The trimodal distributions consisted of a fast mode with tauc's around 10(-5) s, an intermediate mode with tauc's between 10(-4) and 0.3 s, and a slow mode with tauc's generally above 10 s. As the temperature increased from 56 to 90 degreesC, the fast fraction steadily increased from 21% to 50% while its average tauc remained around 10(-5) s; the intermediate fraction remained relatively constant at 23% while its average tauc decreased from 125 to 8 ms, and the rigid fraction decreased from 55% to 32% with an average tauc around 40 s. The fast fraction was attributed to amorphous segments, the rigid fraction to crystalline segments, and the intermediate fraction to segments that formed an interphase between the two. 相似文献
958.
959.
M Laniado-Schwartzman NG Abraham M Conners MW Dunn RD Levere A Kappas 《Canadian Metallurgical Quarterly》1997,53(8):1069-1075
Heme oxygenase (HO), by catabolizing heme to bile pigments, down-regulates cellular levels of heme and hemeproteins; certain of the latter, i.e. cytochrome P450s, generate pro-inflammatory products from endogenous substrates. Two HO isozymes, the products of distinct genes, have been described; HO-1 is the inducible one, whereas HO-2 is believed to be constitutively expressed. We studied the inducing effects of several metal compounds [CoCl2, SnCl2, ZnCl2, heme, and cobalt protoporphyrin (CoPP)] on HO-1 mRNA content and enzyme activity in cultures of rabbit corneal epithelial (RCE) cells; these metal compounds are known to induce HO in other tissues. Additionally, we studied HO-1 expression in an experimental model of ocular inflammation produced in rabbit corneas by extended contact lens wear, and the relation of HO expression to the induced inflammatory process. SnCl2 added to RCE cells in vitro produced marked time- and concentration-dependent increases in HO-1 mRNA and HO-1 enzyme activity; CoCl2, ZnCl2, and CoPP were inducers of HO as well, though to a lesser degree than SnCl2. Corneas treated for 6 days with contact lenses impregnated with SnCl2 displayed substantially less corneal inflammation, swelling, and new vessel invasion than did controls; attenuation of ocular inflammation was paralleled by SnCl2-induced increases in HO mRNA and HO activity in corneal epithelial cells from treated eyes. It is suggested that amelioration of the inflammatory response produced by extended contact lens wear is due, in part, to the induction of high levels of HO-1 activity by SnCl2, which results in diminished production of pro-inflammatory mediators generated through heme-dependent metabolic processes. Regulation of HO activity in this manner may have clinical applications. 相似文献
960.
An intervention, with forgiveness toward their abuser as the goal, was implemented with 12 female incest survivors. The women, from a midwestern city, were 24 to 54 years old, and all were Caucasian. A yoked, randomized experimental and control group design was used. The participants were randomly assigned to an experimental group (receiving the forgiveness intervention immediately) or a waiting-list control group (receiving the intervention when their matched experimental counterpart finished the intervention). Each participant met individually with the intervener once per week. The average length of the intervention for the 12 participants was 14.3 months. A process model of forgiveness was used as the focus of intervention. Dependent variables included forgiveness, self-esteem, hope, psychological depression, and state-trait anxiety scales. After the intervention, the experimental group gained more than the control group in forgiveness and hope and decreased significantly more than the control group in anxiety and depression. When the control group then began the program they showed similar change patterns to the above, as well as in self-esteem improvement. 相似文献