Th1-like cytokine production profile and individual specific alterations in TCRBV-gene usage of T cells from newly diagnosed type 1 diabetes patients after stimulation with beta-cell antigens

Thirty complete coding sequences of human major histocompatibility complex (Mhc) class II DRB alleles, spanning 237 codons, were analyzed for phylogenetic information using distance, parsimony, and likelihood approaches. Allelic genealogies derived from different parts of the coding sequence (exon 2, the 5' and 3' ends of exon 2, respectively, and exons 3-6) were compared. Contrary to prior assertions, a rigorous analysis of allelic genealogies in this gene family cannot be used to justify the claim that the lineage leading to modern humans contained on average at least 100,000 individuals. Phylogenetic inferences based upon the exon 2 region of the DRB loci are complicated by selection and recombination, so this part of the gene does not provide a complete and accurate view of allelic relationships. Attempts to reconstruct human history from genetic data must use realistic models which consider the complicating factors of nonequilibrium populations, recombination, and different patterns of selection.     

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.     

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.     

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)     

Minimum attack rate for measuring measles vaccine efficacy

BACKGROUND: For evaluating measles vaccine efficacy (VE) in the field, some investigators have suggested that an overall attack rate level of 5% or more in a randomly mixing population is sufficient to provide equal exposure to the viral agent in both vaccinated and unvaccinated groups. It is not clear, however, if this assumption is valid given the effect of herd immunity. METHODS: We created a computer simulation model based on the stochastic extension of the Reed-Frost model and tested for variation in bias in VE estimation due to herd immunity, based on runs of 200 trials. RESULTS: At higher levels of attack rate, the degree of herd immunity decreases, as does the percentage of trials with bias in VE estimation. The two main factors that affect the level of attack rate are the probability of adequate contact and the number of susceptibles. At a given level of attack rate, the number of susceptibles is positively associated with the percentage of biased trials in VE estimation. Since vaccination reduces the number of susceptibles, we also observe that when controlling for attack rate, higher vaccination coverage results in lower bias in VE estimation. CONCLUSION: The results show that the assumption of no bias when the attack rate is 5% or more becomes increasingly true when a large percentage of a randomly mixing population is immune.     

Detecting and correcting hyperlipidemia

The dangers of elevated serum cholesterol levels--and in particular, of increased concentrations of small, dense lipoproteins--have been fully delineated. Although effective therapies are available, too many physicians fail to look for hypercholesterolemia, or fail to treat it effectively. Adhering to therapeutic guidelines and encouraging patient compliance can be lifesaving.     

Coordinated action of glutathione S-transferases (GSTs) and multidrug resistance protein 1 (MRP1) in antineoplastic drug detoxification. Mechanism of GST A1-1- and MRP1-associated resistance to chlorambucil in MCF7 breast carcinoma cells

To examine the role of multidrug resistance protein 1 (MRP1) and glutathione S-transferases (GSTs) in cellular resistance to antineoplastic drugs, derivatives of MCF7 breast carcinoma cells were developed that express MRP1 in combination with one of three human cytosolic isozymes of GST. Expression of MRP1 alone confers resistance to several drugs representing the multidrug resistance phenotype, drugs including doxorubicin, vincristine, etoposide, and mitoxantrone. However, co-expression with MRP1 of any of the human GST isozymes A1-1, M1-1, or P1-1 failed to augment MRP1-associated resistance to these drugs. In contrast, combined expression of MRP1 and GST A1-1 conferred approximately 4-fold resistance to the anticancer drug chlorambucil. Expression of MRP1 alone failed to confer resistance to chlorambucil, showing that the observed protection from chlorambucil cytotoxicity was absolutely dependent upon GST A1-1 protein. Moreover, using inhibitors of GST (dicumarol) or MRP1 (sulfinpyrazone), it was shown that in MCF7 cells resistance to chlorambucil requires both intact MRP1-dependent efflux pump activity and, for full protection, GST A1-1 catalytic activity. These results are the first demonstration that GST A1-1 and MRP1 can act in synergy to protect cells from the cytotoxicity of a nitrogen mustard, chlorambucil.