Serum keratan sulfate is a promising marker of early articular cartilage breakdown

OBJECTIVES

To find serum markers that may serve as indices for an early diagnosis of degeneration or damage of the articular cartilage.

METHODS

Twenty-four healthy volunteers, 19 individuals with knee trauma (KT) and 31 with knee osteoarthritis (OA) were evaluated. KT patients were divided into a group (n = 5) with an injury <2 months old (recent KT) and a group (n = 14) with that >2 months old (old KT). Articular cartilage damage was assessed using either arthroscopy or direct observation. Serum concentrations of hyaluronic acid (HA), cartilage proteoglycan aggrecan turnover epitope (CS846) and cartilage oligomeric protein (COMP) were measured using enzyme-linked immunosorbent assay kits and those of keratan sulfate (KS) and chondroitin-6-sulfate (C6S) using high-performance liquid chromatography.

RESULTS

Serum KS in the recent KT group (2095 +/- 594 ng/ml) was significantly higher than that in the old KT group (1373 +/- 418 ng/ml; P = 0.021), and serum COMP in the recent KT group (1572 +/- 182 ng/ml) showed a tendency that was higher than that in the old KT group (1350 +/- 250 ng/ml; P = 0.079). Serum KS in OA patients with Kellgren and Lawrence (KL) grades 0 and I (1456 +/- 334 ng/ml) showed a tendency that was higher than that in OA patients with KL grades II, III and IV (1248 +/- 220 ng/ml; P = 0.084).

CONCLUSIONS

The serum concentration of KS correlated with the damage of the articular cartilage and it was significantly increased even at an early stage after the injury.

Stimulation of Cultured Cerebellar Granule Cells via Glutamate Receptors Induces TRE- and CRE-Binding Activities Mediated by Common DNA-Binding Complexes

By use of nuclear mini-extracts prepared from cultured cerebellar granule cells in a gel-mobility assay, exogenous N-methyl-D-aspartate (NMDA) or kainate was shown to increase both 12-O-tetradecanoylphorbol 13-acetate-responsive element (TRE)- and cyclic AMP-responsive element (CRE)-binding activity. These increases were specifically prevented by the NMDA receptor antagonist D,L-2-amino-5-phosphonovalerate and the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione, respectively. The increase of TRE-binding activity was dependent on de novo protein synthesis, and its inductions by both NMDA and kainate required extracellular Ca2+. TRE-binding activity was competitively inhibited by the CRE, and vice versa, showing higher DNA-binding affinity to the CRE than to the TRE. A proteolytic clipping bandshift assay demonstrated that the increase in CRE-binding activity could be mediated by the TRE-binding activity. Thus, the TRE-binding activity cross-binding to the CRE could be activated by NMDA or kainate stimulation. The involvement of c-Fos or Fos-related proteins in the TRE- and CRE-binding complexes was shown by a supershift gel-mobility assay using anti-c-Fos antiserum.

Sliding movements of molluscan and algal myosin attached to a magnetizable bead under a load controlled by electromagnet

We developed an electromagnetic apparatus to perform a quick change in load in the motility system, using magnetizable beads on which myosin thick filaments from molluscan smooth muscle or green algae, Chara, myosin were attached. The quick change in load to beads (diameter 4.5 microm) was applied in the range of 0-85 pN. The movement of beads was recorded by a video-system and analyzed with special software. When the quick increase in load was applied during the movement of beads under no load, the beads showed a transient movement to the reverse direction before the steady slower movement to the normal direction. When the application of load was stopped, the beads showed a transient fast phase of movement. The change in load-sustaining ability was measured by a double load step. The backward velocity at the second constant test load was smaller when the first preceding step was increased, suggesting that the ability to sustain load was higher with a higher preceding step. These phenomena were observed both in molluscan thick filaments and in Chara myosin, and the time course of the movement of a bead was quite similar to those observed previously in frog single muscle fibers. This suggested that the velocity transients are the intrinsic properties induced by the interaction between actin and myosin, irrespective of the hexagonal lattice structure of filaments, the regular sarcomere structure, and myosin type, namely, that the molecule of myosin itself has the ability to adjust to mechanical circumstances.

Treatment of external iliac artery dissection with endovascular stent placement in a patient with simultaneous pancreas and kidney transplantation

Dissection of the external iliac artery is a rare but serious complication after transplantation, leading to graft loss. Stent angioplasty has been accepted for iliac artery dissection, but the safety and benefits of this procedure in transplantation are unclear. We report a case of right external iliac artery dissection with simultaneous kidney and pancreas transplantation, which was noticed during the operation. A self-expandable metallic stent was inserted from the right femoral artery to the dissected area and arterial blood flow was immediately restored. The postoperative clinical course was uneventful and soon after transplantation both the kidney and pancreas graft functioned well. Together with a previously reported six cases of stent replacement with transplantation and our case, no complication related to this procedure was reported, and in six cases the arterial flow was restored and graft function was improved. Endovascular stent replacement may be a safe and effective procedure for iliac artery dissection in transplantation.

Pioglitazone increases circulating adiponectin levels and subsequently reduces TNF-alpha levels in Type 2 diabetic patients: a randomized study

BACKGROUND

Adipocytokines are involved in the development of insulin resistance and endothelial dysfunction in diabetic patients. However, the relationship between these factors remains unclear. We observed a chronological change in circulating adipocytokines and blood pressure levels with administration of oral hypoglycaemic agents in Type 2 diabetic (T2DM) subjects.

METHODS

Thirty poorly controlled T2DM subjects (aged 60.1 +/- 1.5 years, 11 males and 19 females) were randomized into two groups: voglibose (initial dose 0.6 mg/day, increased to 0.9 mg/day) and pioglitazone (initial dose 15 mg/day, increased to 30 mg/day).

RESULTS

Both treatment groups showed a similar improvement in glycaemic control. In pioglitazone-treated patients, circulating adiponectin levels were significantly increased from 4 weeks after the start of treatment, and until the end of the study at 12 weeks. Plasma tumour necrosis factor-alpha (TNF-alpha) levels were significantly decreased only at 12 weeks. In contrast, no significant changes in plasma adiponectin or TNF-alpha levels were observed in voglibose-treated patients. Plasma PAI-1 and leptin levels were not significantly changed at 12 weeks in either treatment group. Pioglitazone significantly decreased systolic and diastolic blood pressure levels at 12 weeks, but voglibose had no effect.

CONCLUSION

In summary, pioglitazone caused an immediate increase in circulating adiponectin levels, followed by a reduction of TNF-alpha. The observed increase in circulating adiponectin could be related to decreases in both systolic and diastolic blood pressure.

Sources of Activator Calcium Ions in the Contraction of Smooth Muscles in Aplysia kurodai

The physiological and pharmacological properties of contraction and the ultrastructure of buccal mass retractor muscle (I4) and gill-pinnule closure muscle (GPCM) in Aplysia kurodai were studied to learn more about the sources of activator Ca2+ in molluscan smooth muscle. Acetylcholine (ACh) and high K+-induced contractions were reduced by lowering the external Ca2+ concentration, and eliminated by the removal of extracellular Ca2+. Nifedipine appreciably reduced ACh- and high K+-induced contractions, while amiloride decreased only ACh-induced contractions and had no significant effect on high K+-induced contractions. When nifedipine and amiloride were applied together, either type of contraction was still appreciable. Serotonin (5-HT) could potentiate subsequent ACh- and high K+-induced contractions in I4; potentiated tension was significantly reduced by nifedipine and amiloride, whereas 5-HT inhibited ACh-and high K+-induced contractions in GPCM. The potentiating effects of 5-HT may be mediated by the activation of the Ca2+-channel to increase the influx from extracellular Ca2+. Caffeine caused contractions in Ca2+-free solution in both muscles. Electron microscopy revealed sarcolemmal vesicles underneath the plasma membrane in both muscle fibers. Electron microscopical cytochemistry demonstrated that pyroantimonate precipitates were localized in the sarcolemmal vesicles and in the inner surface of plasma membranes in the resting fibers. Present results indicate that the contractions of I4 and GPCM fibers are caused not only by Ca2+-influx but also by Ca2+ release from the intracellular storage sites, such as the sarcolemmal vesicles and the inner surface of plasma membranes.

Enhancement of twitch force by stretch in a nerve-skeletal muscle preparation of the frog Rana porosa brevipoda and the effects of temperature on it

We investigated the mechanism of the enhancement of twitch force by stretch and the effects of temperature on it in nerve-skeletal muscle preparations of whole iliofibularis muscles isolated from the frog Rana brevipoda. When a preparation was stimulated indirectly and stretched, the twitch force after the stretch was enhanced remarkably in comparison to that observed before a stretch at low temperature. The enhanced force obtained by a stretch of 20% resting muscle length (l0) at low temperature was as high as the force obtained by direct stimulation. The phenomenon was not dependent on the velocity but on the amplitude of stretch. The enhanced force obeyed the length-force relationship when a stretch was long enough. The above results were observed when the frogs were kept at room temperature (20-22 degrees C). Measurements were also taken at low temperature (4 degrees C); when frogs were kept at low temperature for more than 2 months, twitch force obtained without stretch was considerably higher at l0. The amplitude of the action potential recorded extracellularly from the muscle surface increased remarkably after a stretch, but was same before and after a stretch when recorded from the nerve innervating muscle. The effects of temperature on twitch and tetanic force by direct or indirect stimulation without stretch were also studied as basic data of the stretch experiment. The results from this study suggest that stretch-induced force enhancement in a nerve-muscle preparation is caused by an increase in the transmission rate between nerve and muscle, and the amplitude of the enhanced force is determined by the length-force relationship of the muscle. The phenomenon is also strongly affected by the temperature at which the frogs are kept.

Endoplasmic reticulum stress response is involved in nonsteroidal anti-inflammatory drug-induced apoptosis

Apoptosis induced by nonsteroidal anti-inflammatory drugs (NSAIDs) is involved not only in the production of NSAID-induced gastric lesions but also in the antitumor activity of these drugs. The endoplasmic reticulum (ER) stress response is a cellular mechanism that aids in protecting the ER against ER stressors and is involved in ER stressor-induced apoptosis. Here, we examine the relationship between this response and NSAID-induced apoptosis in cultured guinea-pig gastric mucosal cells. Exposure of cells to indomethacin, a commonly used NSAID, induced GRP78 as well as CHOP, a transcription factor involved in apoptosis. Three factors that positively regulate CHOP expression (ATF6, ATF4 and XBP-1) were activated and/or induced by indomethacin. NSAIDs other than indomethacin (diclofenac, ibuprofen and celecoxib) also induced CHOP. Monitoring of the transcriptional activities of ATF6 and CHOP by luciferase assay revealed that both were stimulated in the presence of indomethacin. Furthermore, indomethacin-induced apoptosis was suppressed in cultured guinea-pig gastric mucosal cells by expression of the dominant-negative form of CHOP, or in peritoneal macrophages from CHOP-deficient mice. These results suggest that ER stress response-related proteins, particularly CHOP, are involved in NSAID-induced apoptosis.

Marked developmental changes in heme oxygenase-1 (HO-1) expression in the mouse placenta: correlation between HO-1 expression and placental development

Heme catabolism during embryonic period is not well understood. It has been suggested that placental heme oxygenase (HO)-1, which is an inducible isoform of the rate-limiting enzyme in the heme degradation pathway, may be involved in supporting normal fetal development. In this study, we examined the distribution of HO-1 protein in the developing mouse embryo, as well as developmental changes of ho-1 gene expression, and the enzyme activity of HO and biliverdin IXalpha reductase (BVR-A) in placenta. Ectoplacental cone in embryonic day (E) 6.5 embryo already showed HO-1 protein expression, which became restricted only to trophoblastic cells after placenta formation was completed on day E14.5. The placenta of E13.5-E14.5 embryos expressed high levels of HO-1 mRNA, which was decreased significantly towards the end of pregnancy. However, HO-1 expression in placenta was significantly higher than uterus throughout the gestational period. In contrast to HO-1, the placental level of BVR-A activity remained low and did not show changes throughout the gestational period. The correlation between HO-1 expression and placental development suggests that HO-1 might be essential for normal embryonic development.

The influences of L(+)-lactate and pH on contractile performance in rabbit glycerinated skeletal muscle

To know whether L(+)-lactate directly induces the decrease in muscle contractile performance, several parameters of cross-bridge function were measured at various concentrations of lactate and pH in glycerinated rabbit psoas and soleus muscles at three different temperatures (5, 20, 28 degrees C). At all pHs studied (pH 7.0, 6.5, 6.0, and 5.5), isometric tension, unloaded velocity of shortening, and stiffness of a fiber during active and resting state in the presence of 50 mM lactate were not virtually different from those in the absence of lactate, but pH had remarkable effects on these parameters. The active stiffness decreased only slightly, and the small resting stiffness appeared at low pH; they were not affected by the presence of lactate. The present results indicate that the lactate anions may not have marked influence on the interaction between actin and myosin, and the concomitant change in pH with the production of lactate may remarkably affect it, as far as they were examined under the existing conditions of the experimental solutions.