Contrasting effects of midazolam on induction of heat shock protein 27 by vasopressin and heat in aortic smooth muscle cells

We previously showed that vasopressin stimulates the induction of heat shock protein (HSP) 27, a low molecular-weight HSP, through protein kinase C activation in aortic smooth muscle A10 cells. In the present study, we examined the effects of midazolam, an intravenous anesthetic, on the HSP27 induction stimulated by vasopressin, heat, or sodium arsenite (arsenite) in A10 cells. Midazolam inhibited the accumulation of HSP27 induced by vasopressin or 12-O-tetradecanoylphorbol 13-acetate (TPA), a direct activator of protein kinase C. Midazolam also reduced the vasopressin-induced level of the mRNA for HSP27. In contrast, midazolam enhanced the HSP27-accumulation induced by heat or arsenite. Midazolam also enhanced the heat-increased level of the mRNA for HSP27. However, midazolam had no effect on the dissociation of the aggregated form of HSP27 following stimulation by vasopressin, heat, or arsenite. These results suggest that midazolam suppresses vasopressin-stimulated HSP27 induction in vascular smooth muscle cells, and that this inhibitory effect is exerted at a point downstream from protein kinase C. In contrast, midazolam enhanced heat- or arsenite-stimulated HSP27 induction. Thus, midazolam has dual effects on the HSP27 induction stimulated by various stresses in vascular smooth muscle cells.

The role of TNF-alpha in the pathogenesis of inflammation and joint destruction in rheumatoid arthritis (RA): a study using a human RA/SCID mouse chimera

OBJECTIVE

In order to elucidate which cytokine preferentially stimulates the synovium in patients with rheumatoid arthritis (RA), we investigated the roles of tumour necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) using SCID mice engrafted with human RA tissue (SCID-HuRAg).

METHODS

The SCID-HuRAg mice were prepared according to our previously described method. First, SCID-HuRAg mice were treated with chimeric anti-TNF-alpha monoclonal antibody (mAb, 100 microg/mouse) and histological changes were examined 4 weeks after the initial treatment. Secondly, a total of 100 microg of recombinant TNF-alpha or IL-6 (0.6 microg/h) was administered daily to mice using an osmium pump. The histological changes and serum cytokine levels were examined 4 weeks after the initial administration. Human immunoglobulin G (IgG) was administered to mice as a control.

RESULTS

Synovial inflammatory cells were significantly decreased after the anti-TNF-alpha mAb treatment; conversely, the degree of synovial inflammation was significantly exacerbated by TNF-alpha administration. The levels of both IL-6 and TNF-alpha in sera were significantly increased by recombinant TNF-alpha administration, while TNF-alpha levels were unchanged by IL-6 administration. This suggests that TNF-alpha controls IL-6 production. Despite the profound changes in inflammation, we found no effects on bone and no articular cartilage damage was produced by TNF-alpha.

CONCLUSION

This study provides strong evidence that TNF-alpha is a key molecule in the control of the inflammatory changes that occur in the RA synovium. In addition, TNF-alpha regulates IL-6 production. However, other inflammatory pathways independent of TNF-alpha may contribute to the bone and cartilage damage seen in RA.

Mechanism of prostaglandin E2-stimulated heat shock protein 27 induction in osteoblast-like MC3T3-E1 cells

We investigated the effect of prostaglandin E2 (PGE2) on the induction of heat shock protein 27 (HSP27) and HSP70, and the mechanism behind the induction in osteoblast-like MC3T3-E1 cells. PGE2 time-dependently increased the level of HSP27 without affecting the level of HSP70. PGE2 stimulated the accumulation of HSP27 dose-dependently in the range between 10 nM and 10 microM. PGE2 stimulated the increase in the level of the mRNA for HSP27. Staurosporine and calphostin C, inhibitors of protein kinase C (PKC), suppressed the PGE2-induced HSP27 accumulation. The effect of PGE2 on HSP27 accumulation was reduced in the PKC down-regulated cells. BAPTA/AM, a chelator of intracellular Ca2+, or TMB-8, an inhibitor of intracellular Ca2+ mobilization, reduced the accumulation of HSP27 induced by PGE2. Dibutyryl cAMP had little effect on the basal level of HSP27. PGE2 induced the phosphorylation of both p44/p42 mitogen-activated protein (MAP) kinase and p38 MAP kinase. PD98059 and U-0126, inhibitors of the upstream kinase of p44/p42 MAP kinase, reduced the accumulation of HSP27 induced by PGE2. SB203580, a specific inhibitor of p38 MAP kinase, suppressed the HSP27 accumulation induced by PGE2. U-73122, an inhibitor of phospholipase C, and calphostin C reduced the PGE2-induced phosphorylation of both p44/p42 MAP kinase and p38 MAP kinase. These results indicate that PGE2 stimulates the induction of HSP27 through PKC-dependent activations of both p44/p42 MAP kinase and p38 MAP kinase in osteoblasts.

Intelligent system for topic survey in MEDLINE by keyword recommendation and learning text characteristics

We have implemented a system for assisting experts in selecting MEDLINE records for database construction purposes. This system has two specific features: The first is a learning mechanism which extracts characteristics in the abstracts of MEDLINE records of interest as patterns. These patterns reflect selection decisions by experts and are used for screening the records. The second is a keyword recommendation system which assists and supplements experts' knowledge in unexpected cases. Combined with a conventional keyword-based information retrieval system, this system may provide an efficient and comfortable environment for MEDLINE record selection by experts. Some computational experiments are provided to prove that this idea is useful.

The loss of susceptibility to apoptosis in exudated tissue neutrophils is associated with their nuclear factor-kappa B activation

Tissue neutrophils, human salivary neutrophils donated from healthy subjects and synovial fluid neutrophils collected from patients with rheumatoid arthritis were compared with circulating blood neutrophils. Concomitant treatment of circulating blood neutrophils with tumor necrosis factor-alpha (TNF-alpha) and cycloheximide induced neutrophil apoptosis, whereas the same treatment failed to induce significant apoptosis in salivary and synovial fluid neutrophils. Caspase-3 activation by TNF-alpha was observed in these tissue neutrophils, although its activity was significantly weaker than that in circulating blood neutrophils. In circulating blood neutrophils, TNF-alpha induced activation of nuclear factor-kappa B (NF-kappa B), whereas, in tissue neutrophils, NF-kappa B had been already activated without any stimulation, and no further activation was induced by the treatment with TNF-alpha. Furthermore, while pretreatment of neutrophils with an NF-kappa B inhibitor produced typical apoptotic changes in circulating blood neutrophils, this inhibitor did not produce any morphological apoptotic changes induced by TNF-alpha in tissue neutrophils. These results indicate that neutrophils undergo marked functional changes such as altered sensitivity to apoptosis-inducing stimuli in association with their exudation from blood into tissue, and that NF-kappa B activation is involved in the acquisition of resistance to TNF-alpha-induced apoptosis.

Inhibition by adenylyl cyclase-cAMP system of ET-1-induced HSP27 in osteoblasts

We have previously reported that endothelin-1 (ET-1) stimulates heat shock protein (HSP) 27 induction in osteoblast-like MC3T3-E1 cells and that p38 mitogen-activated protein (MAP) kinase acts at a point downstream from protein kinase C (PKC) in HSP27 induction. In the present study, we investigated the effect of the adenylyl cyclase-cAMP system on ET-1-stimulated induction of HSP27 in MC3T3-E1 cells. Dibutyryl-cAMP (DBcAMP) dose dependently inhibited the HSP27 accumulation stimulated by ET-1. Forskolin and cholera toxin significantly suppressed the ET-1-stimulated accumulation of HSP27. However, dideoxyforskolin, a forskolin derivative that does not activate cAMP, failed to suppress the ET-1-induced HSP27 accumulation. Forskolin reduced the p38 MAP kinase phosphorylation induced by ET-1 or 12-O-tetradecanoylphorbol-13-acetate (TPA). PGE(1), an extracellular agonist that activates cAMP production, reduced the ET-1-induced HSP27 accumulation. In addition, the phosphorylation of p38 MAP kinase induced by ET-1 or TPA was suppressed by PGE(1). Forskolin, DBcAMP, and PGE(1) suppressed the ET-1-stimulated increase in the mRNA level for HSP27. These results indicate that the adenylyl cyclase-cAMP system has an inhibitory role in ET-1-stimulated HSP27 induction in osteoblasts and that the effect is exerted at the point between PKC and p38 MAP kinase in osteoblasts.

Involvement of p38 MAP kinase in TGF-beta-stimulated VEGF synthesis in aortic smooth muscle cells

Although it is known that transforming growth factor (TGF)-beta induces vascular endothelial growth factor (VEGF) synthesis in vascular smooth muscle cells, the underlying mechanisms are still poorly understood. In the present study, we examined whether the mitogen-activated protein (MAP) kinase superfamily is involved in TGF-beta-stimulated VEGF synthesis in aortic smooth muscle A10 cells. TGF-beta stimulated the phosphorylation of p42/p44 MAP kinase and p38 MAP kinase, but not that of SAPK (stress-activated protein kinase)/JNK (c-Jun N-terminal kinase). The VEGF synthesis induced by TGF-beta was not affected by PD98059 or U0126, specific inhibitors of the upstream kinase that activates p42/p44 MAP kinase. We confirmed that PD98059 or U0126 did actually suppress the phosphorylation of p42/p44 MAP kinase by TGF-beta in our preparations. PD169316 and SB203580, specific inhibitors of p38 MAP kinase, significantly reduced the TGF-beta-stimulated synthesis of VEGF (each in a dose-dependent manner). PD169316 or SB203580 attenuated the TGF-beta-induced phosphorylation of p38 MAP kinase. These results strongly suggest that p38 MAP kinase plays a part in the pathway by which TGF-beta stimulates the synthesis of VEGF in aortic smooth muscle cells.

AlphaB-crystallin, a low-molecular-weight heat shock protein, acts as a regulator of platelet function

It has recently been reported that alphaB-crystallin, a low-molecular-weight heat shock protein, may be released from cells by mechanical stretch. We investigated a physiological role of alphaB-crystallin in platelet function. AlphaB-crystallin inhibited platelet aggregation induced by thrombin or botrocetin in hamsters and humans. These platelets had specific binding sites for alphaB-crystallin. Moreover, alphaB-crystallin significantly reduced thrombin-induced Ca2+ influx and phosphoinositide hydrolysis by phospholipase C in human platelets. Additionally, plasma levels of alphaB-crystallin were markedly elevated in cardiomyopathic hamsters. Levels of alphaB-crystallin in vessel walls after endothelial injury were markedly reduced. Therefore, our results suggest that alphaB-crystallin, which is discharged from vessel walls in response to endothelial injury, acts intercellularly as a regulator of platelet function.

Differential uptake of grepafloxacin by human circulating blood neutrophils and those exudated into tissues

The uptake of the antimicrobial quinolone agent, grepafloxacin, both by human circulating blood neutrophils and by those exudated into tissues, was evaluated in vitro by comparing the intracellular drug concentrations. In circulating blood neutrophils, the uptake of grepafloxacin was rapid and saturable at 37 degrees C. The uptake of grepafloxacin into circulating blood neutrophils was reduced by lowering the environmental temperature or by the presence of metabolic inhibitors, suggesting the involvement of an active transport mechanism. Furthermore, the uptake of grepafloxacin by tissue (salivary) neutrophils was also partially temperature-dependent and was significantly greater than that by circulating blood neutrophils, i.e. exudation of neutrophils into tissue results in a markedly enhanced transport mechanism for grepafloxacin. This phenomenon may be related to the higher defense activity against infection seen in exudated tissue neutrophils.

Activation of p44/p42 mitogen-activated protein kinase limits triiodothyronine-stimulated alkaline phosphatase activity in osteoblasts

It has been shown that thyroid hormone stimulates the activity of alkaline phosphatase, a marker of mature osteoblast phenotype, in osteoblasts. In the present study, we investigated whether p44/p42 mitogen-activated protein (MAP) kinase is involved in the thyroid hormone-stimulated alkaline phosphatase activity in osteoblast-like MC3T3-E1 cells. Triiodothyronine (T(3)) markedly induced the phosphorylation of p44/p42 MAP kinase. PD98059 and U0126, inhibitors of the upstream kinase that activates p44/p42 MAP kinase, significantly enhanced the T(3)-induced alkaline phosphatase activity in a dose-dependent manner. The phosphorylation of p44/p42 MAP kinase induced by T(3) was reduced by U0126. These results strongly suggest that p44/p42 MAP kinase takes part in the thyroid hormone-stimulated alkaline phosphatase activity in osteoblasts and that p44/p42 MAP kinase plays an inhibitory role in the thyroid hormone-effect.

Induction of a novel gelatinolytic activity in synovial tissue of patients with rheumatoid arthritis

Gelatinolytic activity induced by longtime incubation at 37 degrees C was found in extracts of rheumatoid synovial tissues. The enzyme activity was assessed by gelatin zymography and 3H-gelatin degradation assay. The observed enzyme had different characteristics from matrix metalloproteinases; it did not require metal ions for activity. However, metallocheltors blocked activation and addition of some metal ions restored the activation. The molecular size of the enzyme was changed time-dependently. The approximate molecular weight of the first enzyme produced by incubation was 65 kDa and it was converted to a broad size molecule with a molecular weight of 50 kDa after further incubation. Substrate specificity was detected for denatured collagen types I, II, III and IV.

Direct monitoring kinetic studies of DNA polymerase reactions on a DNA-immobilized quartz-crystal microbalance

Catalytic reactions of DNA polymerase I from E. coli (Klenow fragment, KF) were monitored directly with a template/primer (40/25- or 75/25-mer)-immobilized 27-MHz quartz-crystal microbalance (QCM). The 27-MHz QCM is a very sensitive mass-measuring device in aqueous solution, as the frequency decreases linearly with increasing mass on the QCM electrode at the nanogram level. Three steps in polymerase reactions which include 1) binding of DNA polymerase to the primer on the QCM (mass increase); 2) elongation of complementary nucleotides along the template (mass increase); and 3) release of the enzyme from the completely polymerized DNA (mass decrease), could be monitored continuously from the time dependencies of QCM frequency changes. The binding constant (Ka) of KF to the template/primer DNA was 10(8)M(-1) (k(on) = 10(5)M(-1)s(-1) and k(off)= 10(-3)s(-1)), and decreased to 10(6)M(-1) (k'on = 10(4)M(-1)s(-1) and k'off = 10(-2)s(-1)) for completely polymerized DNA. This is due to the 10-fold decrease in binding rate constant (k(on)) and 10-fold increase in dissociation rate constant (k(off)) for completed DNA strands. Ka values depended slightly on the template and primer sequences. The kinetic parameters in the elongation process (k(cat) and Km) depended only slightly on the DNA sequences. The repair process during the elongation catalyzed by KF could also be monitored in real time as QCM frequency changes.

Photochemically induced equilibrium dysfunction in the hamster model with evaluation by means of a new globe rotatory test system

Thrombosis in the inner ear is regarded as one of the causes of equilibrium dysfunction. We have established an experimental thrombosis model by producing a photochemical reaction between rose bengal and green light, and have evaluated the dysfunction with a new rotatory test system. Hamsters were treated with tissue-type plasminogen activator (tPA) in doses of 0, 0.13, 0.26, and 0.52 mg/kg. The equilibrium dysfunction of the hamsters was evaluated by scoring their behavior according to visual observation and by measuring their time on the rotatory test system. Treatment of animals with sufficient tPA (> or = 0.26 mg/kg) caused a significant amelioration of the behavior and a concomitant significant prolongation of time on the rotating globe. These findings suggest that the equilibrium dysfunction induced by the photochemical reaction was due to the thrombi formed, and that our test system may provide a useful tool for evaluating equilibrium dysfunction in hamsters.

Reconstituting telomerase activity using the telomerase catalytic subunit prevents the telomere shorting and replicative senescence in human osteoblasts

The rate of bone formation is largely determined by the number of osteoblasts, which in turn is determined by the rate of replication of progenitors and the life span of mature cells, reflecting the timing of death by apoptosis. However, the exact age-dependent changes of the cellular activity, replicative potential, and life span of osteoblasts have not been investigated to date. Here, we present evidence that the cellular activity, telomere lengths, and replicative life span of osteoblastic cells obtained from juxta-articular bone marrow gradually decrease with the advance of donor age. Recently, telomerase reverse transcriptase (hTERT) has been identified as a human telomerase catalytic subunit. We transfected the gene encoding hTERT into telomerase-negative human osteoblastic cells from donors and osteoblastic cell strain NHOst 54881 cells and showed that expression of hTERT induces telomerase activity in these osteoblastic cells. In contrast to telomerase-negative control cells, which exhibited telomere shortening and senescence after 10-15 population doublings, telomerase-expressing osteoblastic cells had elongated telomere lengths and showed continued alkaline phosphatase activity and procollagen I C-terminal propeptide (PICP) secretion for more than 30 population doublings. These results indicate that osteoblasts with forced expression of hTERT may be used in cell-based therapies such as ex vivo gene therapy, tissue engineering, and transplantation of osteoblasts to correct bone loss or osteopenia in age-related osteoporotic diseases.

Mechanism of prostaglandin D(2)-stimulated heat shock protein 27 induction in osteoblasts

We previously showed that prostaglandin D(2) (PGD(2)) stimulates activation of protein kinase C (PKC). We investigated whether PGD(2) stimulates the induction of heat shock protein (HSP) 27 and HSP70 in osteoblast-like MC3T3-E1 cells and the mechanism underlying the induction. PGD(2) increased the levels of HSP27 while having little effect on HSP70 levels. PGD(2) stimulated the accumulation of HSP27 dose dependently in the range between 10 nM and 10 microM. PGD(2) induced an increase in the levels of mRNA for HSP27. The PGD(2)-stimulated accumulation of HSP27 was reduced by staurosporine or calphostin C, inhibitors of PKC. PGD(2) induced the phosphorylation of p44/p42 mitogen-activated protein (MAP) kinase and p38 MAP kinase. The HSP27 accumulation induced by PGD(2) was significantly suppressed by PD98059, an inhibitor of the upstream kinase of p44/p42 MAP kinase, or SB203580, an inhibitor of p38 MAP kinase. Calphostin C suppressed the PGD(2)-induced phosphorylation of p44/p42 MAP kinase and p38 MAP kinase. PD98059 or SB203580 suppressed the PGD(2)-increased levels of mRNA for HSP27. These results strongly suggest that PGD(2) stimulates HSP27 induction through p44/p42 MAP kinase activation and p38 MAP kinase activation in osteoblasts and that PKC acts at a point upstream from both the MAP kinases.

Methotrexate inhibits rheumatoid synovitis by inducing apoptosis

OBJECTIVE

To clarify the pharmacological action of methotrexate (MTX) on the synovium of patients with rheumatoid arthritis (RA) using severe combined immunodeficient (SCID) mice in which human RA synovial tissue had been grafted (SCID-HuRAg).

METHODS

One month after engraftment of human RA tissue into SCID mice, MTX (0.3 mg/kg) was administered orally, then the appearance of apoptosis in the grafted tissue was examined by TdT mediated dUTP nick end labeling (TUNEL) staining and electron microscopy at various time points after MTX administration. In cultured synovial cells, synovial apoptotic changes after MTX treatment were studied by agarose gel electrophoresis and flow cytometric analysis. To compare the histological changes induced by MTX with those induced by other disease modifying antirheumatic drugs (DMARD) and a nonsteroidal antiinflammatory drug, histological examination of the grafted synovial tissues from SCID-HuRAg mice was conducted after 4 weeks of oral administration of MTX (0.3 mg/kg/week), salazosulfapyridine (30 mg/kg/day), auranofin (0.2 mg/kg/day), bucillamine (10 mg/kg/day), or indomethacin (2 mg/kg/day).

RESULTS

A significant decrease in the number of inflammatory cells was observed in the grafted synovial tissue of MTX treated SCID-HuRAg. A similar antiinflammatory effect was not observed with the other DMARD. Induction of apoptosis was noted with MTX treatment but not with the others. The pro-apoptotic effect of MTX was also observed in synovial cell cultures.

CONCLUSION

MTX induces apoptosis in RA synovium that, in turn, may contribute to its antiinflammatory effect on RA synovitis.

Involvement of p70 S6 kinase in bone morphogenetic protein signaling: vascular endothelial growth factor synthesis by bone morphogenetic protein-4 in osteoblasts

In the present study, we investigated the effect of bone morphogenetic protein (BMP)-4 on the synthesis of vascular endothelial growth factor (VEGF) in osteoblast-like MC3T3-E1 cells. BMP-4 significantly stimulated VEGF synthesis time-dependently up to 48 h. The stimulatory effect was dose-dependent in the range between 1 and 100 ng/ml. BMP-4 time-dependently phosphorylated p70 S6 kinase. Rapamycin, an inhibitor of p70 S6 kinase, suppressed the BMP-4-stimulated VEGF synthesis as well as the phosphorylation of p70 S6 kinase. The VEGF synthesis by BMP-4 was suppressed by wortmannin and LY294002, inhibitors of phosphatidylinositol 3-kinase. Both wortmannin and LY294002 inhibited the BMP-4-stimulated phosphorylation of p70 S6 kinase. BMP-4 did not affect the phosphorylation of Akt/protein kinase B. Taken together, our results strongly suggest that p70 S6 kinase takes part in BMP-4-stimulated VEGF synthesis as a positive regulator in osteoblasts and that phosphatidylinositol 3-kinase acts at a point upstream from p70 S6 kinase.

Involvement of p70 S6 kinase in bone morphogenetic protein signaling: vascular endothelial growth factor synthesis by bone morphogenetic protein-4 in osteoblasts

In the present study, we investigated the effect of bone morphogenetic protein (BMP)-4 on the synthesis of vascular endothelial growth factor (VEGF) in osteoblast-like MC3T3-E1 cells. BMP-4 significantly stimulated VEGF synthesis time-dependently up to 48 h. The stimulatory effect was dose-dependent in the range between 1 and 100 ng/ml. BMP-4 time-dependently phosphorylated p70 S6 kinase. Rapamycin, an inhibitor of p70 S6 kinase, suppressed the BMP-4-stimulated VEGF synthesis as well as the phosphorylation of p70 S6 kinase. The VEGF synthesis by BMP-4 was suppressed by wortmannin and LY294002, inhibitors of phosphatidylinositol 3-kinase. Both wortmannin and LY294002 inhibited the BMP-4-stimulated phosphorylation of p70 S6 kinase. BMP-4 did not affect the phosphorylation of Akt/protein kinase B. Taken together, our results strongly suggest that p70 S6 kinase takes part in BMP-4-stimulated VEGF synthesis as a positive regulator in osteoblasts and that phosphatidylinositol 3-kinase acts at a point upstream from p70 S6 kinase.

Proximal M2 false aneurysm after head trauma--Case report

A 72-year-old male presented with a post-traumatic false aneurysm of the right proximal M2 artery with massive subarachnoid hemorrhage after closed head injury. Serial computed tomography (CT) and angiography showed the development of the aneurysm which was verified at autopsy. He was admitted in a drowsy state just after a motorcycle accident. Initial brain CT showed subarachnoid hemorrhage without skull fracture. Follow-up brain CT showed a huge hematoma in the right temporal lobe. He died 47 hours after the accident. Histological examination of the aneurysm showed a false aneurysm. Delayed diagnosis of traumatic aneurysms leads to high mortality, so early surgical treatment is essential to save such patients.

Intra-articular injection of hyaluronate (SI-6601D) improves joint pain and synovial fluid prostaglandin E2 levels in rheumatoid arthritis: a multicenter clinical trial

OBJECTIVE

The relationship between clinicalfeatures and biochemical parameters of synovialfluid after serial intra-articular injections of sodium hyaluronate (SI-6601D) was investigated.

METHODS

SI-6601D (sodium hyaluronate with an average molecular weight of 8.4 x 10(5); 25mg/2.5ml/syringe) was injected intra-articularly into the knees of 25 patients with rheumatoid arthritis (RA) every week for 5 consecutive weeks. Clinical and biochemical parameters were monitored before and after injection. Clinicalfindings included pain, as a summation of 3 categories (pain at rest, pain in motion and pain in passive motion, each assessed on a 4-step rating scale), and inflammation, also as a summation of 3 categories (swelling, patellar ballotement and local warmth, each assessed on a 4-step rating scale). Pain on walking of patient was qualitatively assessed by visual analogue scale (VAS). The aspirated volume of synovialfluid (SFV) was recorded and levels of prostaglandin (PG) E2, transforming growth factor beta-1, tumor necrosis factor alpha, interleukin I receptor antagonist, chondroitin 4-sulfate (C4S) and chondroitin 6-sulfate were measured.

RESULTS

Significant improvement in pain symptoms (p < 0.0001), inflammation (p < 0.0001), VAS pain (p < 0.001) and SFV (p < 0.05) were observed after the 5 injections. Levels of PGE2 (p < 0.05) and C4S (p < 0.05) in the synovialfluid were significantly decreased.

DISCUSSION

SI-6601D improved local clinical symptoms in RA patients by suppressing PGE2 and, therefore, may be a useful treatment for local inflammation in RA.

Visualization and detectability of elements rarely contained in soft tissue by X-ray scanning analytical microscopy and electron-probe micro analysis

The detectability of elements rarely contained in soft tissue was compared using X-ray scanning analytical microscope (XSAM) and electron-probe micro analysis (EPMA). Mapping images of Ca, S and P in normal soft tissue of the rat and dissolved Ni in Ni implanted soft tissue could be obtained by XSAM and EPMA. EPMA was more sensitive in detection of P, while XSAM was superior for Ca, S and Ni mapping. The high detectability for heavier elements by XSAM was explained by the large volume of characteristic X-ray generation in XSAM and low attenuation of the characteristic X-rays from heavier elements. XSAM could provide clearer mapping images for heavier elements whose concentration was low without radiation damage to specimens.

Biocompatibility and osteogenesis of refractory metal implants, titanium, hafnium, niobium, tantalum and rhenium

To evaluate the biocompatibility of refractory metals, titanium, hafnium, niobium, tantalum and rhenium were implanted in rats, and histological observation and elemental mapping were performed by X-ray scanning analytical microscope (XSAM) and electron probe microanalyzer (EPMA). The titanium, hafnium, niobium, tantalum and rhenium wires were implanted in the subcutaneous tissue of the abdominal region and in femoral bone marrow of rats for either 2 or 4 weeks. No inflammatory response was observed around the implants, and all the implants were encapsulated with thin fibrous connective tissue. No dissolution of these metals was detected by XSAM in the soft tissue. Histological examination of the hard tissue showed that the amount of new bone formation decreased slightly from the second to the fourth week after implantation, and that the percentage of bone in contact with the implant increased markedly over the same period. No dissolution of these metals was detected by EPMA in the hard tissue. The Ca and P intensities in the mapping images of newly formed bone were higher after 4 weeks than those after 2 weeks, which suggests that the newly formed bone continued to mature from 2 to 4 weeks after implantation. These results indicate that titanium, hafnium, niobium, tantalum and rhenium have good biocompatibility and osteoconductivity.

Stimulatory effect of basic fibroblast growth factor on induction of heat shock protein 27 in osteoblasts: role of protein kinase C

In a previous study we showed that basic fibroblast growth factor (bFGF) stimulates activation of protein kinase C through phosphoinositide hydrolysis by phospholipase C and phosphatidylcholine hydrolysis by phospholipase D in osteoblast-like MC3T3-E1 cells. In the present study, we investigated whether bFGF stimulates the induction of heat shock protein (HSP) 27, a low-molecular-weight HSP, and HSP70, a high-molecular-weight HSP, in MC3T3-E1 cells and the mechanism behind the induction. bFGF increased the level of HSP27 while having little effect on HSP70 level. bFGF stimulated the accumulation of HSP27 dose-dependently in the range between 1 and 30 ng/ml. bFGF induced an increase in the level of the mRNA for HSP27. The bFGF-stimulated accumulation of HSP27 was reduced by inhibitors of protein kinase C. The bFGF-induced HSP27 accumulation was reduced in protein kinase C-downregulated MC3T3-E1 cells. U-73122, an inhibitor of phospholipase C, and propranolol, a phosphatidic acid phosphohydrolase inhibitor, suppressed the bFGF-stimulated HSP27 accumulation. These results strongly suggest that bFGF stimulates HSP27 induction through protein kinase C activation in osteoblasts.

Characterization of simple and reproducible vascular stenosis model in hypercholesterolemic hamsters

The importance of low-density lipoprotein (LDL) in the etiology of atherosclerosis is well recognized. We have established a reproducible stenosis model in hypercholesterolemic hamsters, and the process of arterial stenosis by thrombus or neointima was studied and compared with that in normal hamsters. The level of plasma LDL was 4.6 times higher in hamsters fed a high-cholesterol diet than in hamsters fed normal food. Endothelial injury in right common carotid arteries was induced using a modified catheter. Arterial blood flow was monitored continuously using a Doppler flow probe. Arterial patency after the initiation of injury in high-cholesterol hamsters was significantly changed as compared with that of normal hamsters. Neointima was observed 2 wk after the vascular injury. The neointimal area of high-cholesterol hamsters was significantly larger than that of normal hamsters. To characterize the stenosis in hypercholesterolemic hamsters, we measured platelet aggregation, thrombin time, activated partial thromboplastin time, and proliferating smooth muscle cells (SMC) in vitro and in vivo. The half-maximal inhibitory concentration value for platelet aggregation induced by thrombin or collagen, the DNA synthesis stimulated by platelet-derived growth factor (PDGF)-BB, and 5-bromo-2-deoxy-uridine labeling indices (proliferating index of SMC in vivo) in high-cholesterol hamsters were each significantly higher than the comparable value from normal hamsters. However, specific binding of PDGF-BB in SMC was not different between the two types of hamsters. Furthermore, we investigated the inhibitory effects of probucol or losartan on neointima formation using this model. Probucol, but not losartan, significantly reduced the neointimal area in hypercholesterolemic hamsters. These findings indicated that high levels of plasma LDL strongly contributed to the development of thrombus and neointima formation via both up-regulation of platelet aggregation and the enhancement of SMC proliferation. This stenosis model may be useful for the investigation of hypercholesterolemia-associated cardiovascular diseases.

[Relationship between periarticular osteoporosis and osteoblast senescence in patients with rheumatoid arthritis]

The rate of bone formation is largely determined by the number of osteoblasts, which in turn is determined by the rate of replication of progenitors and the life-span of mature cells, reflecting the timing of death by apoptosis. However, the exact age-dependent changes of the cellular activity, replicative potential and life-span of osteoblasts have not so far been investigated to date. Here we present evidence that the cellular activity, telomere lengths and replicative life-span of osteoblastic cells obtained from juxta-articular bone marrow gradually decrease with the advance of donor age in patients with rheumatoid arthritis or osteoarthritis. Recently, human telomerase reverse transcriptase (hTERT) has been identified as a human teromerase catalytic subunit. We postulate that an expansion of the life-span of osteoblasts and their maintenance as differentiated bone matrix-producing cells may allow for autologus or allogenic cell and gene therapy in bone and joint diseases including osteoporosis. We therefore transfected human osteoblasts with a vector expressing hTERT cDNA, and investigated whether the replicative life-span can be expanded by the introduction of telomerase in human osteoblasts.