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This study was done to verify the validity and the reliability of the newly developed Computerized Dementia Screening Test (CDST) to be easily used in the primary care setting of Korea.Comparison of the results of CDST between 103 healthy control subjects and 41 patients who were diagnosed as having mild cognitive impairment or early dementia, having a clinical dementia rate of 0.5-1 from one health examination center and two neurology clinics in university hospitals.In order to estimate the criterion-related validity, logistic regression analysis for dementia was done using the four individual test results of CDST, age and educational level. The correlation between Korean Mini-Mental State Examination (K-MMSE) and the predicted probability of mild cognitive impairment and early dementia from the logistic regression was measured to verify its validity. The reliability of CDST was measured by test-retest reliability.The sensitivity and specificity of CDST were 75.6% and 94.2%, respectively, if the cut-off point was set to be 0.5 in the logistic regression model. The Pearson's Correlation Coefficient between K-MMSE and the predicted probability of mild cognitive impairment and early dementia from the logistic regression analysis was 0.59 (P0.001). The overall test-retest reliability using the predicted probability of dementia from the logistic regression analysis of CDST was 0.89 (P=0.01).The validity and reliability of CDST is adequate for use as a screening tool to identify mild cognitive impairment and early dementia in Korean primary care.

When the monocyte infiltrates a tissue, adhesion to the extracellular matrix provides structural anchors, and the cell may be deformed through these attachments. To test the hypothesis that human monocytes/macrophages are mechanically responsive, we studied the effects of small cyclic mechanical deformations on cultured human monocytes/macrophages. When monocytes/macrophages were subjected to 4% strain at 1 Hz for 24 hours, neither matrix metalloproteinase (MMP)-1 nor MMP-3 was induced; however, in the presence of phorbol myristate acetate, strain augmented MMP-1 expression by 5.1 ± 0.7-fold (P < 0.05) and MMP-3 expression by 1.6 ± 0.1-fold (P < 0.05). In contrast, MMP-9 expression was not changed by mechanical strain in the presence or absence of phorbol myristate acetate. Deformation rapidly induced the immediate early response genes c-fos and c-jun. In addition, mechanical deformation induced the transcription factor PU.1, an ets family member that is essential in monocyte differentiation, as well as mRNA for the M-CSF receptor. These studies demonstrate that human monocytes/macrophages respond to mechanical deformation with selective augmentation of MMPs, induction of immediate early genes, and induction of the M-CSF receptor. In addition to enhancing the proteolytic activity of macrophages within repairing tissues, cellular deformation within tissues may play a role in monocyte differentiation.

Mechanical forces and biochemical stimuli may interact to regulate cellular responses. In this study, we tested the hypothesis that very small mechanical strains interact with growth factors in the regulation of matrix metalloproteinase (MMP)-1. Human vascular smooth muscle cells (VSMCs) were cultured on a precoated silicone membrane in a device that imposes a highly uniform biaxial strain. VSMCs cultured on fibronectin were treated with cyclic 1-Hz strains of 0, 1, or 4%, and MMPs were assayed by Western analysis or gelatin zymography. Small strains did not induce MMP-1 in VSMCs, but strain was a potent inhibitor of platelet-derived growth factor (PDGF)- or tumor necrosis factor-alpha-induced synthesis of MMP-1. In contrast, MMP-2 and TIMP-2 levels were not changed by PDGF and/or mechanical strain. VSMCs strained on the 120-kDa chymotryptic fragment of fibronectin or RGD peptides suppressed PDGF-induced expression of MMP-1, indicating that this effect is not mediated by the heparin-binding domain or connecting segment-1 of fibronectin. Northern analysis of ets-1, a transcriptional activator of MMP-1 expression, showed that strain down-regulated ets-1 expression, whereas c-fos expression was augmented. Thus, small deformations can selectively suppress MMP-1 synthesis by VSMCs, demonstrating the exquisite sensitivity of the cell to mechanical stimuli.

The valine sensitive acetolactate synthase (ALS) isozyme from Serratia marcescens ATCC 25419 was purified to homogeneity. Analysis of the native molecular weight of the purified enzyme by the native pore gradient polyacrylamide gel electrophoresis indicated the molecular weight of about 178,000 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed the enzyme to be composed of two different types of subunits with molecular weights of 62,000 and 35,000. The molar ratio of the two polypeptides was estimated to be 1, suggesting that native enzyme is composed of two large subunits and two small subunits. The enzyme exhibits homotropic allosterism with pyruvate unlike other enteric ALS isozymes. The specificity ratio R (V[acetohydroxybutyrate]/V[acetolactate] = R.[alpha-ketobutyrate]/pyruvate]), of the enzyme was found to be 0 suggesting that the Serratia ALS has very high specificity for pyruvate. The pH optimum was around 7.5, and the enzyme was stable at 50 degrees C for 30 min. The pI value for the purified enzyme was 5.2. The concentration of branched chain amino acids for 50% inhibition of the enzyme was 0.1 mM for valine, and 1 mM for leucine and isoleucine, respectively.