Microperoxidases catalytically degrade reactive oxygen species and may be anti-cataract agents

1,25-(OH)2D3 and 24,25-(OH)2D3 mediate their effects on chondrocytes through the classic vitamin D receptor (VDR) as well as through rapid membrane-mediated mechanisms which result in both nongenomic and genomic effects. In intact cells, it is difficult to distinguish between genomic responses via the VDR and genomic and nongenomic responses via membrane-mediated pathways. In this study, we used two hybrid analogues of 1,25-(OH)2D3 which have been modified on the A-ring and C,D-ring side chain (1 alpha-(hydroxymethyl)-3 beta-hydroxy-20-epi-22-oxa-26,27-dihomo vitamin D3 (analogue MCW-YA = 3a) and 1 beta-(hydroxymethyl)-3 alpha-hydroxy-20-epi-22-oxa-26,27-dihomo vitamin D3 (analogue MCW-YB = 3b) to examine the role of the VDR in response of rat costochondral resting zone (RC) and growth zone (GC) chondrocytes to 1,25-(OH)2D3 and 24,25-(OH)2D3. These hybrid analogues are only 0.1% as effective in binding to the VDR from calf thymus as 1,25-(OH)2D3. Chondrocyte proliferation ([3H]-thymidine incorporation), proteoglycan production ([35S]-sulfate incorporation), and activity of protein kinase C (PKC) were measured after treatment with 1,25-(OH)2D3, 24,25-(OH)2D3, or the analogues. Both analogues inhibited proliferation of both cell types, as did 1,25-(OH)2D3 and 24,25-(OH)2D3. Analogue 3a had no effect on proteoglycan production by GCs but increased that by RCs. Analogue 3b increased proteoglycan production in both GC and RC cultures. Both analogues stimulated PKC in GC cells; however, neither 3a nor 3b had an effect on PKC activity in RC cells. 1,25-(OH)2D3 and 3a decreased PKC in matrix vesicles from GC cultures, whereas plasma membrane PKC activity was increased, with 1,25-(OH)2D3 having a greater effect. 24,25-(OH)2D3 caused a significant decrease in PKC activity in matrix vesicles from RC cultures; 24,25-(OH)2D3, 3a, and 3b increased PKC activity in the plasma membrane fraction, however. Thus, with little or no binding to calf thymus VDR, 3a and 3b can affect cell proliferation, proteoglycan production, and PKC activity. The direct membrane effect is analogue-specific and cell maturation-dependent. By studying analogues with greatly reduced affinity for the VDR, we have provided further evidence for the existence of a membrane receptor(s) involved in mediating nongenomic effects of vitamin D metabolites.     

The effects of health beliefs on weight loss in individuals at high risk for NIDDM

OBJECTIVE: To determine whether perceived risk and other health beliefs held by individuals at high risk for developing NIDDM predict weight loss and behavior change during a behavioral weight loss program to reduce the risk of NIDDM. RESEARCH DESIGN AND METHODS: Health beliefs and objective risk factors for diabetes were examined in 154 overweight men and women with a family history of NIDDM. The effects of these factors on adherence, dietary intake, weight loss, and changes in glucose levels were examined in a subset of 79 of these subjects who participated in a 2-year behavioral weight control program. RESULTS: Those subjects who perceived themselves at highest risk of developing diabetes had a stronger family history of the disease and were more likely to be women than subjects considering themselves at more moderate risk. These participants also rated diabetes as a more serious disease, but were less likely to believe that weight loss would lower their risk. None of these health beliefs were related to attendance at meetings, dietary intake, weight loss, or fasting glucose, but higher perceived seriousness predicted larger reductions in BMI at 1 year. Of the objective risk factors for NIDDM, higher baseline BMI predicted larger weight losses throughout the program, and a stronger family history of diabetes was related to greater weight regain after an initial weight loss. CONCLUSIONS: Perceived risk of developing diabetes and other health beliefs did not predict performance in a behavioral weight loss program. These data suggest that efforts to modify health beliefs by educating high-risk individuals about their risk and benefits of weight loss may not be effective in improving long-term weight loss results.     

A system of patient classification: construction and validation of an instrument

It is becoming increasingly evident that growth factors and cytokines play crucial roles in the process of blastocyst implantation. Endometrial differentiation and secretions, embryo development and secretions, and embryo-endometrium interaction leading to implantation require continuous and synchronous dialogue between these two compartments involving endocrine and paracrine regulators. In this review, a model of the endocrinology and paracrinology of blastocyst implantation in the primate is described.     

The use of a new wire in a 6-year-old coronary artery occlusion: the Jagwire recanalization guidewire

Selective, coronary arteriographic, catheter-based, intravascular ultrasound images were obtained to determine the presence and extent of angiographically undetected or underestimated left main (LM) coronary arterial narrowing in patients receiving coronary interventional therapy. Coronary arteriograms were determined to be either normal or abnormal by visual inspection. Abnormal arteriograms were digitized and quantitated using a semiautomated edge-detection algorithm. Thirty-eight patients receiving percutaneous treatment of stenoses in the left coronary artery system were studied. Optimal LM coronary angiograms were obtained in 2 views, and intravascular ultrasound images were obtained after the coronary interventional procedure. Intravascular ultrasound detected plaque in 24 of 27 angiographically normal LM arteries (89%), whereas narrowing was observed in 11 of 11 angiographically abnormal LM arteries (100%). Eight of 38 patients (21%) had > 40% area stenosis by intravascular ultrasound. In patients with angiographic disease, there was no correlation between quantitative angiographic and ultrasound percent area stenosis (r = 0.12; p = 0.72; SEE 19%). The median plaque area was not different between angiographically normal (0.05 cm2; 0.03, 0.08 [25th, 75th percentile]) and abnormal (0.06 cm2; 0.03, 0.1) patients. The median percent area stenosis in arteriographically normal subjects (26%; 14, 32%) was less than that in abnormal ones (37%; 20, 46%) (p = 0.03). Unrecognized LM disease is widespread and often underestimated in patients with normal LM angiograms undergoing interventional procedures. Plaque area is similar for angiographically normal and insignificantly abnormal vessels. This study suggests that intravascular ultrasound overcomes the limitations of silhouette imaging and can be a clinically useful, adjunctive method to evaluate LM coronary artery disease.     

Procoagulant activity in cancer cells is dependent on tissue factor expression

Procoagulant activity of pairs of cell lines, which were derived from the same original cell type but which possess different growth characteristics and metastatic properties, was examined. The following characteristics were considered suggestive of a greater likelihood of metastatic potential: high histological grade; establishment of the line from a metastatic rather than a nonmetastatic cancer; increased tumorigenicity in nude mice; and/or estrogen receptor-negative mammary cancer. Procoagulant activity was evaluated by a two stage clotting assay. Procoagulant activity was highly variable, with up to a 1,300-fold difference, among the cancer cell lines examined. The rate of clot formation was factor VII dependent and was totally inhibited by an anti tissue factor monoclonal antibody, indicating that tissue factor was the only significant procoagulant present in these cancer cells. Tissue factor antigen expression, evaluated by ELISA, correlated with procoagulant activity. In all pairs of cancer cell lines, those with characteristics of increased proliferative potential had increased tissue factor levels compared to cell lines that originated from the same cell type, but which possess less aggressive characteristics. Tissue factor activity in these cancer cells was increased by cell lysis or by exposure of intact cells to a calcium ionophore, similar to results previously obtained in fibroblasts. Tissue factor mRNA was evaluated by northern blot analysis using a specific probe complementary to tissue factor mRNA. The previously described predominant tissue factor mRNA species of 2.2 kb was identified in the majority of cancer cell lines examined, but tissue factor mRNA species of 3.2 to 3.4 kb were also identified.(ABSTRACT TRUNCATED AT 250 WORDS)     

Chemiluminescent reporter gene assays: sensitive detection of the GUS and SEAP gene products

Chemiluminescent assays are described for the secreted alkaline phosphatase (SEAP) and beta-glucuronidase (GUS) reporter gene products. These assays provide simple, sensitive, non-isotopic alternatives to existing detection methods and are performed in microplate or tube luminometers or in a scintillation counter. The SEAP reporter gene product is secreted from mammalian cells and is thus easily detected in a sample of culture medium. Sensitive detection of secreted placental alkaline phosphatase is performed with CSPD chemiluminescent alkaline phosphatase substrate, and approximately 3 fg of enzyme can be detected. GUS has become the major reporter gene used for the analysis of plant gene expression. Sensitive chemiluminescent detection of GUS activity can be performed with an assay system we have developed using Glucuron, a beta-glucuronidase substrate. This chemiluminescent assay detects 60 fg of GUS and is linear over six orders of magnitude of enzyme concentration. CSPD and Glucuron substrates have been incorporated into two new chemiluminescent reporter gene assay kits for SEAP and GUS.     

The development of anti-CD79 monoclonal antibodies for treatment of B-cell neoplastic disease

The B-cell antigen receptor (BCR) consists of cell surface IgM associated with the CD79 alpha/beta heterodimer. In this paper we describe a panel of monoclonal antibodies (mAbs) recognising the extracellular regions of human CD79 alpha and beta. FACS analysis demonstrated that the mAbs bind to a range of Burkitt's lymphoma lines, a mouse B-cell line (JO-72) transfected with human CD79 alpha and beta, and tumour biopsies from NHL patients. The specificity of the mAbs was confirmed by immunoprecipitation. The Ka for the binding of IgG from the anti-CD79 alpha mAbs to cell surface CD79 alpha on Ramos cells was 3 x 10(8) M-1, and their maximum level of binding, 1.7-2 x 10(5) molecules/cell, matched that obtained with anti-Fc mu and anti-Fd mu mAbs. All four anti-CD79 beta mAbs were of lower affinity. Interestingly, in growth arrest studies, we found that while all anti-Fc mu mAbs caused profound inhibition of proliferation of Ramos cells, a range of other anti-BCR mAbs, which included the anti-CD79, anti-Fab mu, anti-gamma and anti-idiotype reagents, all performed poorly giving a maximum of 25% inhibition. These differences in performance are believed to relate to the ability of anti-BCR mAbs to cross-link neighbouring surface BCR and suggest that, unlike anti-Fc mu which favours cross-linking, most of these mAbs are binding in a monogamous, non-cross-linking, union with the BCR.