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991.
Localization of cellular retinoic acid-binding protein (CRABP) II and CRABP in developing rat testis
WL Zheng RA Bucco MC Schmitt SA Wardlaw DE Ong 《Canadian Metallurgical Quarterly》1996,137(11):5028-5035
Retinoic acid (RA) has been implicated as a signaling molecule for the morphogenesis of some tissues and organs. The morphogenesis of the rat testis occurs relatively late in development, culminating in puberty. Two members of the superfamily of small intracellular carrier proteins for lipophilic compounds are cellular Ra-binding protein (CRABP) and cellular RA-binding protein II (CRABP-II). Both CRABP and CRABP-II are present at various sites in the developing mouse embryo. Here we report the developmental expression and localization of CRABP and CRABP-II in rat testis. Northern blot analysis of CRABP-II demonstrated the highest messenger RNA expression on day 4 (the earliest time point assayed by this technique), decreasing thereafter until day 20, when it became undetectable. Western blot analysis, begun on day 19 of fetal development, indicated that high levels of protein expression in the testis already existed at that time. CRABP messenger RNA expression reached its highest levels between postnatal days 16-20 and decreased thereafter. Immunolocalization revealed that CRABP-II was confined to the fetal population of Leydig and Sertoli cells. We observed that CRABP-II was expressed in certain cells that synthesized retinoic acid in the uterus and ovary (unpublished). The expression of CRABP-II in Sertoli cells and fetal Leydig cells suggested that these cells may well be the site of RA synthesis in the developing testis. CRABP was localized to gonocytes in earlier stages and spermatogonia later, where it was clearly excluded from the nucleus, indicating that the role of CRABP may be to protect these cells from the effects of RA. The reported expression of CRABP-II in embryonal tissues, which are RA responsive and undergoing morphogenesis, coupled with CRABP-II expression in the testis at a critical morphogenic stage suggest that RA may play a prominent role in the morphogenesis of the testis. 相似文献
992.
DA Sloan MB Donnelly RW Schwartz PC McGrath DE Kenady DP Wood WE Strodel 《Canadian Metallurgical Quarterly》1997,64(2):135-142
BACKGROUND: Administration of angiotensin converting enzyme (ACE) inhibitors to patients with congestive heart failure (CHF) is associated to a decrease in the abnormal vasoconstrictor neurohormonal activity. This contributes to the sustained benefits of these drugs on symptoms and survival of patients with CHF. There is little information, however, regarding the effects of ACE inhibition on vasodilator and natriuretic hormones. AIM: To evaluate the chronic effects of enalapril, in addition to digitalis and diuretics in patients with chronic cardiac failure. PATIENTS AND METHODS: Nine patients with an idiopathic dilated cardiomyopathy (8 male, aged 48 to 76 years old) under treatment with digitalis and diuretics, received enalapril 20 mg bid during eight weeks. Before and after this treatment period resting left ventricular ejection fraction, functional class, plasma levels of atrial natriuretic factor and bradykinins (BK) and urinary excretion of kalikreins (BK) and prostaglandin E2 (PGE2) were measured. RESULTS: After enalapril therapy, there was a significant increase in maximal O2 consumption (14.8 +/- 1.2 to 18.6 +/- 1.5 ml/kg/min, p < 0.05) and radionuclide LV ejection fraction (27.4 +/- 1.1 to 31.4 +/- 0.9% p < 0.05). This was associated with a significant decrease in plasma ANP levels (559 +/- 158 to 178 +/- 54.8 pg/ml) and UK (391 +/- 112 to 243 +/- 92 Cu/24 h). CONCLUSIONS: The decrease in ANP levels, which is a well known marker of prognosis in CHF, could contribute to explain the sustained clinical benefits observed with ACE inhibitors in patients with CHF. 相似文献
993.
DE Brough C Hsu VA Kulesa GM Lee LJ Cantolupo A Lizonova I Kovesdi 《Canadian Metallurgical Quarterly》1997,71(12):9206-9213
The persistence of transgene expression has become a hallmark for adenovirus vector evaluation in vivo. Although not all therapeutic benefit in gene therapy is reliant on long-term transgene expression, it is assumed that the treatment of chronic diseases will require significant persistence of expression. To understand the mechanisms involved in transgene persistence, a number of adenovirus vectors were evaluated in vivo in different strains of mice. Interestingly, the rate of vector genome clearance was not altered by the complete deletion of early region 4 (E4) in our vectors. The GV11 (E1- E4-) vector genome cleared with a similar kinetic profile as the GV10 (E1-) vector genome in immunocompetent and immunocompromised mice. These results suggest that the majority of adenovirus vector genomes are eliminated from transduced tissue via a mechanism(s) independent of T-cell, B-cell, and NK cell immune mechanisms. While the levels of persistence of transgene expression in liver or lung transduced with GV10 and GV11 vectors expressing beta-galactosidase, cystic fibrosis transmembrane conductance regulator, or secretory alkaline phosphatase were similar in immunocompetent mice, a marked difference was observed in immunocompromised animals. Levels of transgene expression initially from both GV10 and GV11 vectors were the same. However, GV11 transgene expression correlated with loss of vector genome, while GV10 transgene expression persisted at a high level. Coadministration and readministration of GV10 vectors showed that E4 provided in trans could activate transgene expression from the GV11 vector genome. While transgene expression activity per genome from the GV10 vector is clearly activated, expression from a cytomegalovirus promoter expression cassette in a GV11 vector appeared to be further inactivated as a function of time. Understanding the molecular mechanisms underlying these expression effects will be important for developing persistent adenovirus vectors for chronic applications. 相似文献
994.
DE Coplen 《Canadian Metallurgical Quarterly》1997,157(6):2270-2277
PURPOSE: The widespread use of prenatal ultrasound results in an increased recognition of fetal hydronephrosis and technological advances now make fetal intervention possible. However, efficacy is unknown, and there have been errors in diagnosis, and associated morbidity and mortality. This review focuses on the current status of prenatal diagnosis and management of hydronephrosis. MATERIALS AND METHODS: The relevant literature on prenatal physiology, prenatal diagnosis, experimental obstruction and clinical series of prenatal intervention was reviewed. RESULTS: Prenatal ultrasound is a poor discriminator of physiological hydronephrosis, obstruction, renal dysplasia and reflux. Persistent early onset oligohydramnios is the best predictor of poor neonatal outcome. New minimally invasive techniques may aid diagnostically but they may not improve outcome. Dysplasia is often present by the time hydronephrosis is detected and it is not reversible in experimental models. Prenatal intervention is technically feasible but the survival rate is only 47%, and catheter placement and open fetal surgery have significant fetal and maternal risks. Complications occur in up to 45% of fetuses. CONCLUSIONS: Prenatal intervention for hydronephrosis remains an experimental technique. The most important question is whether prenatal therapy for obstructive uropathy improves survival and decreases long-term morbidity and mortality in affected fetuses. 相似文献
995.
I. ZALACAIN M.J. ZAPELENA M.P. DE PEÑA I. ASTIASARÁN J. BELLO 《Journal of food science》1997,62(5):1076-1079
Six levels of Aspergillus sp. lipase were evaluated and 0.400u/g was selected. A sausage with a starter culture (Lactobacillus plantarum (10%)+Staphylococcus carnosus (90%)), one with lipase and one with both starter culture and lipase were produced in a pilot plant. A lower amount of Micrococcaceae was found in sausages without starter culture. Total FFA quantity at the 15th day was higher in sausages with lipase. Higher amounts of acetic, propionic and butyric acids were found in sausages with both lipase and starter culture. Odor intensity had slightly higher scores in sausages with added lipase. 相似文献
996.
GM McKhann MA Goldsborough LM Borowicz OA Selnes ED Mellits C Enger SA Quaskey WA Baumgartner DE Cameron RS Stuart TJ Gardner 《Canadian Metallurgical Quarterly》1997,63(2):510-515
BACKGROUND: Cognitive deficits have been reported in patients after coronary artery bypass grafting, but the incidence of these deficits varies widely. We studied prospectively the incidence of cognitive change and whether the changes persisted over time. METHODS: Cognitive testing was done preoperatively and 1 month and 1 year postoperatively in 127 patients undergoing coronary artery bypass grafting. Tests were grouped into eight cognitive domains. A change of 0.5 standard deviation or more at 1 month and 1 year from patient's preoperative Z score was the outcome measure. RESULTS: We identified four main outcomes for each cognitive domain: no decline; decline and improvement; persistent decline; and late decline. Only 12% of patients showed no decline across all domains tested; 82% to 90% of patients had no decline in visual memory, psychomotor speed, motor speed, and executive function; 21% and 26% had decline and improvement in verbal memory and language; approximately 10% had persistent decline in the domains of verbal memory, visual memory, attention, and visuoconstruction; and 24% had late decline (between 1 month and 1 year) in visuoconstruction. CONCLUSIONS: This study establishes that the incidence of cognitive decline varies according to the cognitive domain studied and that some patients have persistent and late cognitive changes in specific domains after coronary artery bypass grafting. 相似文献
997.
998.
Calcium (Ca2+) channels are present in non-excitable as well as in excitable cells. In bone cells of the osteoblast lineage, Ca2+ channels play fundamental roles in cellular responses to external stimuli including both mechanical forces and hormonal signals. They are also proposed to modulate paracrine signaling between bone-forming osteoblasts and bone-resorbing osteoclasts at local sites of bone remodeling. Calcium signals are characterized by transient increases in intracellular Ca2+ levels that are associated with activation of intracellular signaling pathways that control cell behavior and phenotype, including patterns of gene expression. Development of Ca2+ signals is a tightly regulated cellular process that involves the concerted actions of plasma membrane and intracellular Ca2+ channels, along with Ca2+ pumps and exchangers. This review summarizes the current state of knowledge concerning the structure, function, and role of Ca2+ channels and Ca2+ signals in bone cells, focusing on the osteoblast. 相似文献
999.
1000.
ME Van Amburgh DM Galton DE Bauman RW Everett DG Fox LE Chase HN Erb 《Canadian Metallurgical Quarterly》1998,81(2):527-538
beta1A integrin subunits with point mutations of the cytoplasmic domain were expressed in fibroblasts derived from beta1-null stem cells. beta1A in which one or both of the tyrosines of the two NPXY motifs (Y783, Y795) were changed to phenylalanines formed active alpha5 beta1 and alpha6 beta1 integrins that mediated cell adhesion and supported assembly of fibronectin. Mutation of the proline in either motif (P781, P793) to an alanine or of a threonine in the inter-motif sequence (T788) to a proline resulted in poorly expressed, inactive beta1A. Y783,795F cells developed numerous fine focal contacts and exhibited motility on a surface. When compared with cells expressing wild-type beta1A or beta1A with the D759A activating mutation of a conserved membrane-proximal aspartate, Y783, 795F cells had impaired ability to transverse filters in chemotaxis assays. Analysis of cells expressing beta1A with single Tyr to Phe substitutions indicated that both Y783 and Y795 are important for directed migration. Actin-containing microfilaments of Y783,795F cells were shorter and more peripheral than microfilaments of cells expressing wild-type beta1A. These results indicate that change of the phenol side chains in the NPXY motifs to phenyl groups (which cannot be phosphorylated) has major effects on the organization of focal contacts and cytoskeleton and on directed cell motility. 相似文献