Transfer of epinastine to infants through human breast milk.

The purpose of this study was to develop an analytical method for analyzing epinastine in breast milk and maternal plasma samples to determine the safety of epinastine in breastfed infants. Six nursing mothers took epinastine hydrochloride (20 mg) once a day for 7 days, while a nursing mother took it for 30 days. Breast milk and blood samples were collected 2, 4, and 10 h after administration from the volunteers. A liquid chromatography-mass spectrometry system was used to analyze samples pretreated by liquid-liquid extractions. The concentration of epinastine in human milk was 10.3-33.5 ng/mL after 2 h, 9.1-63.8 ng/mL after 4 h, and 8.3-28.9 ng/mL after 10 h. The increase achieved 4 h after administration indicates that epinastine was transferred into human breast milk. However, the milk-to-plasma ratio had a wide range (0.82-3.39), while the relative infant dose at 4 h was 0.36-2.49%, which is lower than the safety level of transferability (10%). Moreover, the plasma levels of epinastine in two infants were slightly below the quantification limit. Overall, our results suggested that epinastine can safely be used by nursing mothers without affecting their infants.

Trends in incidence and mortality of tuberculosis in Japan: a population-based study, 1997-2016.

Japan is still a medium-burden tuberculosis (TB) country. We aimed to examine trends in newly notified active TB incidence and TB-related mortality in the last two decades in Japan. This is a population-based study using Japanese Vital Statistics and Japan Tuberculosis Surveillance from 1997 to 2016. We determined active TB incidence and mortality rates (per 100 000 population) by sex, age and disease categories. Joinpoint regression was applied to calculate the annual percentage change (APC) in age-adjusted mortality rates and to identify the years showing significant trend changes. Crude and age-adjusted incidence rates reduced from 33.9 to 13.9 and 37.3 to 11.3 per 100 000 population, respectively. Also, crude and age-adjusted mortality rates reduced from 2.2 to 1.5 and 2.8 to 1.0 per 100 000 population, respectively. Average APC in the incidence and mortality rates showed significant decline both in men (-6.2% and -5.4%, respectively) and women (-5.7% and -4.6%, respectively). Age-specific analysis demonstrated decreases in incidence and mortality rates for every age category, except for the incidence trend in the younger population. Although trends in active TB incidence and mortality rates in Japan have favourably decreased, the rate of decline is far from achieving TB elimination by 2035.

Mucocutaneous inflammation in the Ikaros Family Zinc Finger 1-keratin 5-specific transgenic mice.

BACKGROUND: Our genomewide association study documented an association between cold medicine-related Stevens-Johnson syndrome/toxic epidermal necrolysis (CM-SJS/TEN) and Ikaros Family Zinc Finger 1 (IKZF1). Few studies examined biological and pathological functions of IKZF1 in mucosal immunity. We hypothesized that IKZF1 contributes to the mucocutaneous inflammation. METHODS: Human skin and conjunctival tissues were obtained for immunohistological studies. Primary human conjunctival epithelial cells (PHCjECs) and adult human epidermal keratinocytes (HEKa) also used for gene expression analysis. We also generated K5-Ikzf1-EGFP transgenic mice (Ikzf1 Tg) by introducing the Ik1 isoform into cells expressing keratin 5, which is expressed in epithelial tissues such as the epidermis and conjunctiva, and then examined them histologically and investigated gene expression of the epidermis. Moreover, Ikzf1 Tg were induced allergic contact dermatitis. RESULTS: We found that human epidermis and conjunctival epithelium expressed IKZF1, and in PHCjECs and HEKa, the expression of IKZF1 mRNA was upregulated by stimulation with polyI:C, a TLR3 ligand. In Ikzf1 Tg, we observed dermatitis and mucosal inflammation including the ocular surface. In contact dermatitis model, inflammatory infiltrates in the skin of Ikzf1 Tg were significantly increased compared with wild type. Microarray analysis showed that Lcn2, Adh7, Epgn, Ifi202b, Cdo1, Gpr37, Duoxa1, Tnfrsf4, and Enpp5 genes were significantly upregulated in the epidermis of Ikzf1 Tg compared with wild type. CONCLUSION: Our findings support the hypothesis that Ikaros might participate in mucocutaneous inflammation.

Clinical efficacy and safety of monthly oral ibandronate 100 mg versus monthly intravenous ibandronate 1 mg in Japanese patients with primary osteoporosis.

UNLABELLED: The MOVEST study evaluated the efficacy and safety of monthly oral ibandronate versus licensed monthly IV ibandronate in Japanese osteoporotic patients. Relative BMD gains after 12 months were 5.22 % oral and 5.34 % IV, showing non-inferiority of oral to IV ibandronate (primary endpoint). No new safety concerns were identified. INTRODUCTION: The randomized, phase 3, double-blind MOVEST (Monthly Oral VErsus intravenouS ibandronaTe) study evaluated the efficacy and safety of monthly oral ibandronate versus the licensed monthly intravenous (IV) ibandronate regimen in Japanese patients with osteoporosis. METHODS: Ambulatory patients aged ≥ 55 years with primary osteoporosis were randomized to receive oral ibandronate 100 mg/month plus monthly IV placebo, or IV ibandronate 1 mg/month plus monthly oral placebo. The primary endpoint was non-inferiority of oral versus IV ibandronate with respect to bone mineral density (BMD) gains at the lumbar spine after 12 months of treatment. RESULTS: Four hundred twenty-two patients were enrolled with 372 patients in the per-protocol set (183 and 189 in the oral and IV ibandronate groups, respectively). The relative change from baseline in lumbar spine BMD values for the oral and IV ibandronate groups, respectively, was 5.22 % (95 % confidence interval [CI] 4.65, 5.80) and 5.34 % (95 % CI 4.78, 5.90). The least squares mean difference between the two groups was -0.23 % (95 % CI -0.97, 0.51), showing non-inferiority of oral ibandronate to IV ibandronate (non-inferiority limit = -1.60). Changes in BMD values at other sites, and bone turnover marker levels in the oral ibandronate group, were comparable with those of the IV group. The safety profile was similar to that previously demonstrated; no new safety concerns were identified. CONCLUSIONS: This study demonstrated the non-inferiority of oral ibandronate 100 mg/month to IV ibandronate 1 mg/month (licensed dose in Japan) in increasing lumbar spine BMD in Japanese patients with primary osteoporosis.

Aberrant IDH3α expression promotes malignant tumor growth by inducing HIF-1-mediated metabolic reprogramming and angiogenesis.

Cancer cells gain a growth advantage through the so-called Warburg effect by shifting glucose metabolism from oxidative phosphorylation to aerobic glycolysis. Hypoxia-inducible factor 1 (HIF-1) has been suggested to function in metabolic reprogramming; however, the underlying mechanism has not been fully elucidated. We found that the aberrant expression of wild-type isocitrate dehydrogenase 3α (IDH3α), a subunit of the IDH3 heterotetramer, decreased α-ketoglutarate levels and increased the stability and transactivation activity of HIF-1α in cancer cells. The silencing of IDH3α significantly delayed tumor growth by suppressing the HIF-1-mediated Warburg effect and angiogenesis. IDH3α expression was associated with the poor postoperative overall survival of lung and breast cancer patients. These results justify the exploitation of IDH3 as a novel target for the diagnosis and treatment of cancers.

Involvement of decreased hypoxia-inducible factor 1 activity and resultant G1-S cell cycle transition in radioresistance of perinecrotic tumor cells.

Cancer patients often suffer from local tumor recurrence after radiation therapy. Some intracellular and extracellular factors, such as activity of hypoxia-inducible factor 1 (HIF-1), cell cycle status and oxygen availability, have been suggested to affect DNA damage responses and eventual radioresistant characteristics of cancer cells. But when, where, and how these factors affect one another and induce cellular radioresistance is largely unknown. Here, we analyzed mechanistic and spatio-temporal relationships among them in highly heterogeneous tumor microenvironments. Experiments in vitro demonstrated that a decrease in the glucose concentration reduced the transcriptional activity of HIF-1 and expression of a downstream gene for the cell cycle regulator p27(Kip1) even under hypoxic conditions. Then, the proportion of cells in the radioresistant S phase increased, whereas that in the radiosensitive G1 phase decreased, significantly. Immunohistochemical analyses showed that cancer cells in perinecrotic hypoxic regions, which should be under low-glucose conditions, expressed little HIF-1α, and therefore, were mainly in S phase and less damaged by radiation treatment. Continuous administration of glucagon, which increases the blood glucose concentration and so improves glucose availability in perinecrotic hypoxic regions, induced HIF-1α expression and increased radiation-induced DNA damage. Taken all together, these results indicate that cancer cells in perinecrotic regions, which would be under low-glucose and hypoxic conditions, obtain radioresistance by decreasing the level of both HIF-1 activity and p27(Kip1) expression, and adjusting their cell cycle to the radioresistant S phase.

Effects of the systemic administration of alendronate on bone formation in a porous hydroxyapatite/collagen composite and resorption by osteoclasts in a bone defect model in rabbits.

Several bisphosphonates are now available for the treatment of osteoporosis. Porous hydroxyapatite/collagen (HA/Col) composite is an osteoconductive bone substitute which is resorbed by osteoclasts. The effects of the bisphosphonate alendronate on the formation of bone in porous HA/Col and its resorption by osteoclasts were evaluated using a rabbit model. Porous HA/Col cylinders measuring 6 mm in diameter and 8 mm in length, with a pore size of 100 µm to 500 µm and 95% porosity, were inserted into a defect produced in the lateral femoral condyles of 72 rabbits. The rabbits were divided into four groups based on the protocol of alendronate administration: the control group did not receive any alendronate, the pre group had alendronate treatment for three weeks prior to the implantation of the HA/Col, the post group had alendronate treatment following implantation until euthanasia, and the pre+post group had continuous alendronate treatment from three weeks prior to surgery until euthanasia. All rabbits were injected intravenously with either saline or alendronate (7.5 µg/kg) once a week. Each group had 18 rabbits, six in each group being killed at three, six and 12 weeks post-operatively. Alendronate administration suppressed the resorption of the implants. Additionally, the mineral densities of newly formed bone in the alendronate-treated groups were lower than those in the control group at 12 weeks post-operatively. Interestingly, the number of osteoclasts attached to the implant correlated with the extent of bone formation at three weeks. In conclusion, the systemic administration of alendronate in our rabbit model at a dose-for-weight equivalent to the clinical dose used in the treatment of osteoporosis in Japan affected the mineral density and remodelling of bone tissue in implanted porous HA/Col composites.

Spiking expression of mu-crystallin mRNA during treatment with methimazole in patients with graves' hyperthyroidism.

mu-Crystallin is an NADPH-dependent cytosolic T3-binding protein. A knockout study in mice showed that mu-crystallin has a physiological function as a reservoir of T3 in the cytoplasm in vivo. Patients with nonsyndromic deafness were reported to have point mutations in the mu-crystallin gene. The expression of mu-crystallin is regulated by multiple factors. The present study was performed to determine whether thyroid function is related to the expression of mu-crystallin mRNA in peripheral mononuclear cells. We examined 23 normal healthy male and female subjects and 15 patients with Graves' disease. mu-Crystallin protein expression was determined immunohistochemically in peripheral mononuclear cells. The expression of mu-crystallin mRNA was assessed by reverse transcription of total RNA from peripheral mononuclear cells followed by quantitative PCR. mu-Crystallin protein was detected in peripheral mononuclear cells. The mRNA expression was negatively correlated with age in normal female subjects. The values in female subjects were significantly higher than those in males. The values were positively correlated with serum TSH concentration. The values of the thyrotoxic patients with Graves' disease were lower than those in healthy subjects. A transient increase in mu-crystallin expression was observed within 14-42 days after the initial treatment with antithyroid medication. Thyroid hormone inversely relates to the expression of mu-crystallin mRNA in euthyroid mononuclear cells. Abrupt suppression of thyroid function leads to overexpression of mu-crystallin mRNA in thyrotoxic mononuclear cells. Thyroid hormone-regulated mu-crystallin expression may control thyroid hormone action via the intracytoplasmic T (3) capacity.

Treatment regimen determines whether an HIF-1 inhibitor enhances or inhibits the effect of radiation therapy.

Hypoxia-inducible factor-1 (HIF-1) has been reported to promote tumour radioresistance; therefore, it is recognised as an excellent target during radiation therapy. However, the inhibition of HIF-1 in unsuitable timing can suppress rather than enhance the effect of radiation therapy because its anti-angiogenic effect increases the radioresistant hypoxic fraction. In this study, we imaged changes of HIF-1 activity after treatment with radiation and/or an HIF-1 inhibitor, YC-1, and optimised their combination. Hypoxic tumour cells were reoxygenated 6 h postirradiation, leading to von Hippel-Lindau (VHL)-dependent proteolysis of HIF-1alpha and a resultant decrease in HIF-1 activity. The activity then increased as HIF-1alpha accumulated in the reoxygenated regions 24 h postirradiation. Meanwhile, YC-1 temporarily but significantly suppressed HIF-1 activity, leading to a decrease in microvessel density and an increase in tumour hypoxia. On treatment with YC-1 and then radiation, the YC-1-mediated increase in tumour hypoxia suppressed the effect of radiation therapy, whereas on treatment in the reverse order, YC-1 suppressed the postirradiation upregulation of HIF-1 activity and consequently delayed tumour growth. These results indicate that treatment regimen determines whether an HIF-1 inhibitor enhances or inhibits the therapeutic effect of radiation, and the suppression of the postirradiation upregulation of HIF-1 activity is important for the best therapeutic benefit.

Treatment of distal radius fractures with a wrist-bridging external fixation: the value of alternating electric current stimulation.

The radiological and functional outcomes of two groups of comminuted intraarticular fractures of the distal radius that were treated with wrist-bridging external fixation, with or without an alternating electric current stimulation (EF + ES or EF group, respectively), were compared. The radial length, radial inclination and palmar tilt were measured on radiographs taken immediately after removal of wrist external fixator and also after bone union had occurred. Furthermore, active range of motion was compared at the final consultation. Bridging callus was observed earlier postoperatively in the EF + ES group than in the EF group. The radial length and palmar tilt were significantly larger, and the loss of radial length and radial inclination significantly smaller, in the EF + ES group. We believe that callus maturation is enhanced by alternating electric current stimulation, which enables the early removal of external fixator.

Cementless total hip replacement after previous intertrochanteric valgus osteotomy for advanced osteoarthritis.

We present a series of 30 uncemented total hip replacements performed between June 1985 and January 2002 with a mean follow-up of seven years (5 to 20) in 27 patients who had previously undergone a valgus intertrochanteric osteotomy. No further osteotomy was undertaken to enable hip replacement. We used a number of uncemented modular or monoblock femoral components, acetabular components and bearings. The patients were followed up clinically and radiologically. We report 100% survival of the femoral component. One acetabular component was revised at five years post-implantation for aseptic loosening. We noted cortical hypertrophy around the tip of the monoblock stems in six patients. We believe that modular femoral components should be used when undertaking total hip replacement in patients who have previously undergone valgus femoral osteotomy.

ED-71, a novel vitamin D analog, promotes bone formation and angiogenesis and inhibits bone resorption after bone marrow ablation.

ED-71, a novel analog of 1alpha,25-(OH)2 D3, increases bone mass to a greater extent than alfacalcidol, an 1alpha,25-(OH)2 D3 prodrug. In this study, we used a murine bone marrow ablation model to compare the effect of ED-71 on bone formation and resorption in vivo with that of 1alpha,25-(OH)2 D3. We discovered that bone matrix remodeling occurring within the first week after bone marrow ablation was enhanced by a single injection of ED-71, but not by 1alpha,25-(OH)2 D3. This enhancement was associated with an increase in bone surface. Trabecular bone resorption occurring from 1 to 2 weeks after the procedure was suppressed by a single injection of ED-71, but not 1alpha,25-(OH)2 D3, with treated mice exhibiting a reduction in osteoclast numbers, despite increases in osteoblast surface. As seen with the single injection, daily administration of ED-71 also enhanced bone modeling. Bone marrow osteoblast differentiation was also augmented by ED-71 pretreatment. Furthermore, ED-71 treatment immediately after bone marrow ablation enhanced angiogenesis within the bone marrow cavity via enhancement of VEGF(120) expression. In this paper, we clearly demonstrate that ED-71 is an orally administered small molecular weight compound with an anabolic effect on bone metabolism.

Plasminogen activator inhibitor-1 aids nerve growth factor-induced differentiation and survival of pheochromocytoma cells by activating both the extracellular signal-regulated kinase and c-Jun pathways.

Astrocytes are thought to be critical to neurons' surviving damage caused by ischemic stroke or other injury. Plasminogen activator inhibitor-1 is one of the active soluble factors released by astrocytes and regulates plasminogen activator-plasmin proteolytic sequence in the CNS as a serpin. In this study, we show that plasminogen activator inhibitor-1 can promote neurite outgrowth and survival of rat pheochromocytoma cells in serum-deprived conditions, and that this neuroprotective activity is correlated with enhanced activation of both extracellular signal-regulated kinases following a direct phosphorylation of nerve growth factor receptor, Trk A, and of c-Jun. Our results suggest that plasminogen activator inhibitor-1 can act as a neurotrophic factor, protecting neurons from serum deprivation-induced neuron death not only by compensating for nerve growth factor functions, but also by activating the c-Jun/activating protein-1 pathway.

Effect of electrical polarization of hydroxyapatite ceramics on new bone formation.

Large surface charges can be induced on hydroxyapatite (HAp) ceramics by proton transport polarization, but this does not affect beta-tricalcium phosphate (TCP) because of its low polarizability. We wished to examine differences in osteogenic cell activity and new bone growth between positively or negatively surface-charged HAp and HAp/TCP plates using a calvarial bone defect model. In the first group of rats, test pieces were placed with their positively charged surfaces face down on the dura mater. In the second group, test pieces were placed with their negatively charged surfaces face down on the dura mater. A third group received noncharged test pieces. Histological examination, including enzymatic staining for osteoblasts and osteoclasts, was carried out. While no bone formation was observed at the pericranium, direct bone formation on the cranial bone debris and new bone growth expanded from the margins of the sites of injury to bridge across both the positively and negatively charged surfaces of HAp and HAp/TCP plates occurred. Electrical polarization of implanted plates, including positive charge, led to enhanced osteoblast activity, though decreased osteoclast activity was seen on the positively charged plate surface. Thus, polarization of HAp ceramics may modulate new bone formation and resorption.

The lower lumbar spine moment and the axial rotational motion of a body during one-handed and double-handed backhand stroke in tennis.

To analyze the load on the lumbar spine and the motion pattern of a body during a backhand stroke when playing tennis, kinematic and kinetic data of eleven amateur tennis players were collected. Each subject performed one-handed and double-handed strokes at low, medium, and high racket speeds. The three-dimensional motion of the strokes was optically measured by tracking markers attached to their body segments. Floor reaction forces were measured for the right and left feet separately. Using the body motion and the floor reaction force data, the lower lumbar spine moment was calculated based on a segment-link model. Peak and plateau values of the joint moment before and after ball impact were analyzed statistically using a factorial ANOVA (stroke, racket speed). Similarly, the axial rotation angle of the pelvis against the feet and that of the shoulder against the pelvis were analyzed. In all the moments except the lateral bending moment before ball impact and all the rotation angles, there were significant main effects of racket speed. The one-handed strokes showed significantly smaller extension moment before ball impact as well as smaller lateral bending and axial rotation moments after ball impact than the double-handed strokes. The one-handed strokes also showed a significantly smaller axial rotation angle of the shoulder against the pelvis and that of the pelvis against the feet. These results indicate that during one-handed strokes the shoulder and elbow joints share the rotational motion necessary for backhand strokes and consequently reduce the maximal moments imposed on the spinal joints.

Effect of paroxetine on marble-burying behavior in mice.

The present study was undertaken to investigate the effect of paroxetine, a selective serotonin reuptake inhibitor (SSRI), on marble-burying behavior in mice in comparison with those of fluvoxamine and clomipramine. Marble-burying test is extensively used as an animal model for obsessive/compulsive disorder. A significant inhibition in marble-burying behavior was observed with paroxetine, at a dose of 10 mg/kg. The earlier SSRI, fluvoxamine, also significantly inhibited marble-burying behavior at a dose of 30 mg/kg. Although clomipramine, a tricyclic antidepressant, caused an inhibition in marble-burying behavior, a high dose of 100 mg/kg was needed to show a significant effect. On the other hand, all the drugs used in the present study showed no significant changes in spontaneous locomotor activity at doses inhibiting marble-burying behavior. In conclusion, it was confirmed that paroxetine has a potent inhibitory effect on marble-burying behavior in mice, and could have a similar antiobsessive/anticompulsive activity in human beings.

Antioxidant effect of a new calcium antagonist, azelnidipine, in cultured human arterial endothelial cells.

Azelnidipine is a novel dihydropyridine-type calcium antagonist with long-acting anti-hypertensive action and a low reported incidence of tachycardia. We aimed to evaluate its antioxidant activity in cultured human arterial endothelial cells under oxidative stress. Endothelial cells were exposed to 1 mM H2O2 and treated with 100 microM alpha-tocopherol, 1 nM, 10 nM or 100 nM azelnidipine, 100 nM nifedipine or 100 nM amlodipine. After 3 h, the cell number and level of lipid peroxidation were evaluated by measuring the total protein and 8-iso-PGF2 alpha concentrations, respectively. The total protein concentration was similar with each treatment. Inhibition of 8-iso-PGF2 alpha was greatest with 10 nM azelnidipine (compared with the other drugs); the difference between 10 nM and 100 nM azelnidipine was not significant. We conclude that azelnidipine has a potent antioxidative effect that could be of significant clinical benefit when combined with its long-lasting anti-hypertensive action and low incidence of tachycardia.

Vestibular projection to the periarcuate cortex in the monkey.

Vestibular inputs to the cerebral cortex are important for spatial orientation, body equilibrium, and head and eye movements. We examined vestibular input to the periarcuate cortex in the Japanese monkey by analyzing laminar field potentials evoked by electrical stimulation of the vestibular nerve. Laminar field potential analysis in the depths of the cerebral cortex showed that vestibular-evoked potentials consisted of early-positive and late-negative potentials and early-negative and late-positive potentials in the superficial and deep layers of the periarcuate cortex, respectively, with latencies of 4.8-6.3 ms, suggesting that these potentials were directly conveyed to the cortex through the thalamus. These potentials were distributed continuously in the fundus, dorsal and ventral banks of the spur and the bottom of the junctional part of the arcuate sulcus and spur. This vestibular-projecting area overlapped the cortical distribution of corticovestibular neurons that were retrogradely labeled by tracer injection into the vestibular nuclei (previously reported area 6 pa), and also the distribution of smooth pursuit-related neurons recorded in the periarcuate cortex including area 8 in a trained monkey. These results are discussed in relation to the function of vestibular information in control of smooth pursuit and efferents of the smooth pursuit-related frontal eye field.

Effects of [Arg8]-vasopressin on regional cerebral blood flow in spontaneously hypertensive rats.

The effects of [Arg(8)]-vasopressin (AVP) and related compounds on regional cerebral blood flow (rCBF) in the hippocampus were studied using conscious spontaneously hypertensive rats (SHR). rCBF in the hippocampus decreased gradually with age in proportion to an increase in mean blood pressure. Subcutaneous injection of AVP caused a dose-dependent increase in rCBF in the hippocampus. The effects of the metabolic fragments AVP4-9 and AVP4-8 on rCBF were relatively weak. OPC-31260, a vasopressin V(2) antagonist, antagonized the AVP-induced increase in rCBF in the hippocampus. Furthermore, subcutaneous injection of DDAVP, a V(2) agonist, increased rCBF in the hippocampus. On the other hand, the AVP-induced increase in rCBF in the hippocampus was not antagonized by OPC-21268, a vasopressin V(1) antagonist. Intracerebroventricular injection of AVP caused no significant changes in rCBF in the hippocampus, even at a dose of 10 ng/site.

Bone morphogenetic protein-2 enhances osterix gene expression in chondrocytes.

Osterix is a recently identified zinc-finger-containing transcription factor, which is required for skeletogenesis as no bone formation was observed in osterix-deficient mice. Osterix was first cloned as a gene whose expression was enhanced by BMP in C2C12 cells. As BMP induces ectopic bone formation in vivo via a pathway reminiscent to endochondral bone formation, BMP may also regulate osterix gene expression in chondrocytes. However, no information was available regarding the BMP actions on osterix gene expression in chondrocytes. We therefore examined the effects of BMP-2 on osterix gene expression in chondrocytes in culture. RT-PCR analysis indicated that osterix mRNA was expressed in the primary cultures of chondrocytes derived from mouse rib cartilage. The treatment with BMP-2 enhanced the levels of osterix transcripts within 24 h and the enhancement was still observed at 48 h based on RT-PCR analysis. This BMP effect was specific to this cytokine, as TGF-beta did not alter osterix gene expression. BMP effects on the osterix mRNA levels were also confirmed by Northern blot analysis. The enhancing effect of BMP on osterix gene expression was observed in a dose-dependent manner starting at 200 ng/ml. The BMP enhancement of the osterix gene expression in chondrocytes was blocked in the presence of a protein synthesis inhibitor, cycloheximide, while it was still observed in the presence of 5,6-dichloro-1-beta D-ribofuranosylbenzimidazol (DRB) suggesting the involvement of post-transcriptional events, which require new protein synthesis. These results indicated that osterix gene is expressed in the primary cultures of chondrocytes and its expression is under the control of BMP-2.