Serum interleukin 6 levels are associated with depressive state of the patients with knee osteoarthritis irrespective of disease severity

Clinical Rheumatology - This cross-sectional study investigated the prevalence of depressive state and association between depressive state and serum interleukin (IL)-6 levels in knee...     

Monoclonal antibody typing of Chlamydia psittaci strains derived from avian and mammalian species.

A total of 77 Chlamydia psittaci strains of avian, human, and mammalian origin were grouped into four serovars with 11 monoclonal antibodies recognizing the lipopolysaccharide and the major outer membrane protein antigens. The avian and human strains, which were closely related to each other, were distinct from the mammalian strains. Immunological typing of C. psittaci with monoclonal antibodies seems practical.     

Structure and function of a hexameric copper-containing nitrite reductase

Dissimilatory nitrite reductase (NIR) is a key enzyme in denitrification, catalyzing the first step that leads to gaseous products (NO, N(2)O, and N(2)). We have determined the crystal structure of a Cu-containing NIR from a methylotrophic denitrifying bacterium, Hyphomicrobium denitrificans, at 2.2-A resolution. The overall structure of this H. denitrificans NIR reveals a trigonal prism-shaped molecule in which a monomer consisting of 447 residues and three Cu atoms is organized into a unique hexamer (i.e., a tightly associated dimer of trimers). Each monomer is composed of an N-terminal region containing a Greek key beta-barrel folding domain, cupredoxin domain I, and a C-terminal region containing cupredoxin domains II and III. Both cupredoxin domains I and II bind one type 1 Cu and are combined with a long loop comprising 31 amino acid residues. The type 2 Cu is ligated at the interface between domain II of one monomer and domain III of an adjacent monomer. Between the two trimeric C-terminal regions are three interfaces formed by an interaction between the domains I, and the type 1 Cu in the domain is required for dimerization of the trimer. The type 1 Cu in domain II functions as an electron acceptor from an electron donor protein and then transfers an electron to the type 2 Cu, binding the substrate to reduce nitrite to NO. The discussion of the intermolecular electron transfer process from cytochrome c(550) to the H. denitrificans NIR is based on x-ray crystallographic and kinetic results.     

Improved blood compatibility of DLC coated polymeric material

There is currently an increasing interest in the use of DLC (diamond like carbon) films in biomedical applications. These investigations making use of DLC in the biomedical area indicate its attractive properties. In this study, we succeeded in depositing DLC on polymer substrates and found the best conditions and method for this application. We evaluated the blood compatibility of polycarbonate substrates coated by DLC (PC-DLC) under different conditions by using epifluorescent video microscopy (EVM) combined with a parallel plate flow chamber. Segmented polyurethane (SPU), which has been used to fabricate medical devices including an artificial heart, and proven to have acceptable blood compatibility, was compared with polycarbonate substrates coated with DLC film. The EVM system measured platelet adhesion on the surface of the DLC, by using whole human blood containing Mepacrine labeled platelets perfuse at a wall shear rate of 100 s(-1) at 1 min intervals for a period of 20 min. PC-DLC demonstrated that Tecoflex showed higher complement activation than PC-DLC. There were significant differences between the PC-DLC substrates. On the basis of these results, it is recommended for use as a coating material in implantable blood contacting devices such as artificial hearts, pacemakers, and other devices. This DLC seems to be a promising candidate for biomaterials applications and merits further investigation.     

Serum hepatitis C virus RNA level as a predictor of subsequent response to interferon-α therapy in Japanese patients with chronic hepatitis C

Serum hepatitis C virus (HCV) RNA level has been shown to be a good predictor of subsequent response to interferon-α (IFN) therapy in US patients in whom genotype 1a/1b are both predominant. To determine whether serum HCV RNA level is a predictor of subsequent response to IFN in Japanese patients or not, appropriately collected pre-IFN therapy serum samples from 35 Japanese patients with chronic HCV infection were studied. Serum HCV RNA level and HCV genotype were determined and correlated with the subsequent response to IFN. Response to IFN was defined by serum alanine transaminase level: complete and sustained response (n = 15), complete response followed by relapse (n = 10), and no response (n = 10). Patients with complete and sustained response had lower pre-IFN serum HCV RNA level (median: RT-PCR+, bDNA-) compared to the complete response to relapse group (median: 5.25 × 10⁶ genome equivalent/ml [eq/ml], P < 0.001) and the no response group (median: 10.63 × 10⁶ eq/ml, P < 0.001). Seven (46.7%) of the complete and sustained response patients had HCV genotype 2a and three patients had a mixture of genotypes 1b and 2a. In contrast, all 10 patients in the complete response to relapse group had genotype 1b whereas 8 of 10 patients in the non-response group had genotype 1b and 2 had genotype 2b. The patients with HCV genotype 2a had lower serum HCV RNA level than those with 1b (P = 0.002). When the HCV viremia were controlled by stratifying them into < and > 10⁶ eq/ml, patients with genotype 1 had a similar complete and sustained response rate compared to genotype 2. These data indicated that pre-IFN serum HCV RNA is also a good predictor of subsequent complete and sustained response in Japanese patients with chronic HCV infection. © 1994 Wiley-Liss, Inc.     

Comparative assessment of pedicle morphology of the lumbar spine in various degenerative diseases

Measurement of the morphological dimensions of the pedicles of the lumbar spine was conducted using computed tomography (CT) to clarify the difference in pedicle morphology among different lumbar degenerative diseases. The subjects were 136 patients with lumbar spinal disorders who underwent myelography followed by CT scans. They were divided into four groups, that is a group of 25 patients with degenerative spondylolisthesis (DS group), a group of 54 patients with lumbar canal stenosis (LCS group), a group of 42 patients with lumbar disc herniation (LDH group), and a control group of 15 patients with spinal cord tumor in cervicothoracic region but without lumbar diseases (control group). Measurements of the transverse diameter, axial length, and axial angle of the pedicles were performed on CT slices obtained at the middle of the pedicle. The transverse diameter was the width of the isthmus, the axial length was the distance between the anterior of the vertebral body and the posterior of the vertebral arch on a line perpendicular to the line bisecting the isthmus, and the axial angle was the angle between the line perpendicular to the line bisecting the isthmus and the midline of the vertebral body. While there were no significant differences in the mean transverse diameter or axial length among the four groups, the mean axial angle was significantly smaller in the DS and LCS groups when compared to that in the LDH and control groups. In the DS and LCS groups, the pedicles were more sagitally oriented than in the LDH and control groups. Such difference in the axial angle of the pedicles in different lumbar diseases should be taken into consideration when placing at the insertion of pedicle screws, because precise orientation of screw insertion would scarcely allow penetration of the pedicle wall.     

Ganglioside GM3 can induce megakaryocytoid differentiation of human leukemia cell line K562 cells

The role of acidic glycosphingolipids in cell growth and differentiation was investigated using the multipotent leukemia cell line K562. When GM3 was added to cell culture media, the growth of K562 cells was remarkably inhibited and the cells were shown to have megakaryocytoid morphology. Ultrastructural study demonstrated that K562 cells treated with GM3 had platelet peroxidase-positive structures, which were considered to be the specific marker of megakaryocyte. Furthermore, AP-3 directed against an epitope present on membrane glycoprotein IIIa reacted with the GM3-treated cells. Free N-acetylneuraminic acid, GM1, GM2, GD1a, and a mixture of bovine brain gangliosides containing GD1a and GT1b did not affect growth of K562 cells or show morphological changes. According to chemical analyses, GM3 content increased in megakaryocytoid differentiation induced by tetradecanoylphorbol-13-acetate, whereas GM3 decreased in erythroid differentiation induced by hemin. Enzymatic analysis showed that the GM3 increase during megakaryocytoid differentiation was a result of the sialyltransferase activation. These results indicated that exogenous GM3 induced differentiation of K562 cells into a "GM3-rich" lineage, i.e., mainly megakaryocytoid lineage, and that GM3 accumulation in the GM3-rich lineage was the result of the activation of GM3 synthase. These findings strongly suggested that GM3 ganglioside, a minor membrane component, has a crucial role in not only the differentiation induction but also the determination of the differentiation direction in pluripotent K562 cells.     

Effect of pump flow mode of novel left ventricular assist device upon end organ perfusion in dogs with doxorubicin induced heart failure

End organ effects of nonpulsatile (NP) and pulsatile (P) left ventricular assist device (LVAD) flow were compared in a canine model of doxorubicin-induced heart failure. After heart failure induction, a prototype bimodal LVAD was implanted. Hemodynamics, cardiac dimensions, and myocardial metabolism were monitored with the LVAD off (baseline) and on (in NP and P modes at 70% or 100% power). End organ perfusion was assessed by colored microsphere analysis. Seven dogs were used: two died before pump implantation and were excluded from analysis, and the remaining five survived to study termination. At 70% NP, ascending aortic flow and myocardial oxygen consumption (MVO2) decreased significantly. At 100% NP, LV dimensions decreased, aortic systolic, pulse, and LV pressures decreased but not significantly, and ascending aorta flow reversed. At 100% NP, coronary blood flow, MVO2, and LV free wall subepicardial and subendocardial blood flows decreased significantly. However, as NP support increased, the subepicardial/subendocardial blood flow ratio remained near baseline. At 100% NP, right ventricular perfusion decreased but not significantly, cerebral perfusion decreased significantly, and renal perfusion stayed constant. P mode results were similar, except that ascending aorta flow decreased significantly at 100% P instead of reversing as at 100% NP. These results suggest that end organ perfusion is not differentially affected by LVAD flow mode during chronic heart failure.     

Physical model-based indirect measurements of blood pressure and flow using a centrifugal pump

This article describes a technique offering indirect measurements of pump pressure differential and flow with certain accuracy independent of changes in blood viscosity. This technique is based on noninvasive measurements of the motor current and rotation speed using the physical model equations of the centrifugal pump system. Blood viscosity included in the coefficients of the dynamic equations is first estimated, and then substitution of the estimated viscosity into the steady equations of the model provides pump flow and pressure differential. In vitro tests using a Capiox pump showed a sufficient linear correlation between actual values and their estimates for pressure differential and pump flow. An in vivo test using a 45 kg sheep showed that the proposed algorithm needs robustness for the convergence of estimates of viscosity. An overall evaluation, however, of the developed algorithm/model showed indications of success in terms of efficient computation and modeling.