Effects of transforming growth factor-β1 on formation and activation of osteoclasts

Transforming growth factor-₁ (TGF-₁) has biological functions in various types of cells. However, its roles in the regulation of osteoclast formation and function are unclear. To examine them, we employed a culture system in which unfractionated cells obtained from long bones of 13-day-old mice were cultured on a dentine slice. We found that TGF-₁ has a potent inhibitory effect on osteoclastic bone resorption at a dose of 0.2–5 ng/ml. By electron microscopy the osteoclasts appeared to have fewer mitochondria and ruffled borders than those in control cultures. But in the presence of 1,25-dihydroxyvitamin D₃, [1,25-(OH)₂D₃], TGF-₁ at a dose of 0.2–1 ng/ml stimulated the formation of osteoclasts from unfractionated bone cell cultures in which preexistent osteoclasts had degenerated. Thus, using stromal cell-free he-mopoietic blast cells, we examined the direct action of TGF-₁ on osteoclast precursors. Although TGF-₁ inhibited tartrate-resistant acid phosphatase-positive (TRAP) multinucleate cell (MNC) formation induced by 1,25-(OH)₂D₃, the conditioned medium (CM) of TGF-₁-treated MC3T3-E1 cells stimulated such formation. These results suggest that TGF-₁ inhibits osteoclastic bone resorption but stimulates osteoclast formation via the action of factor(s) produced by TGF-₁-treated osteoblasts in the presence of 1,25-(OH)₂D₃.     

Impact of preoperative serum sodium concentration in living donor liver transplantation

Background and Aims: The importance of hyponatremia in deceased donor liver transplantation (DDLT) has been recently discussed frequently. However, its impact on the outcomes in living donor liver transplantation (LDLT) has not yet been elucidated. The current study was designed to demonstrate the impact of pre‐transplant sodium concentration on postoperative clinical outcomes. Methods: One hundred and thirty‐four patients who underwent LDLT for end‐stage liver diseases were examined to evaluate the significance of pre‐transplant hyponatremia (Na ≤ 130 mEq/L) on the short‐term clinical outcomes and the efficacy of the Model for End‐Stage Liver Disease and serum sodium (MELD‐Na) score using the sodium concentration and original MELD score. Results: The preoperative sodium and MELD score for all patients were 133.9 mEq/L (range: 109–142) and 16.2 (range: 6–38), respectively. According to a multivariate analysis, not only the MELD score (P = 0.030) but also the sodium concentration (P = 0.005) were found to be significant predictive factors for short‐term graft survival. Preoperative hyponatremia was a significant risk factor for the occurrence of sepsis (P < 0.001), renal dysfunction (P < 0.001) and encephalopathy (P = 0.026). The MELD‐Na score was 19.6 (range: 6–51) and the area under the receiver–operator curve of that (c‐statistics: 0.867) was higher than MELD score and sodium concentration (c‐statistics: 0.820 and 0.842, respectively). Conclusion: Preoperative hyponatremia was a significant risk for postoperative complications and short‐term graft loss. The addition of sodium concentration to MELD score might therefore be an effective predictor for post‐transplant short‐term mortality in LDLT.     

Association of serum NO x level with clustering of metabolic syndrome components in middle-aged and elderly general populations in Japan

Objectives The aim of this study was to determine whether the serum nitrite plus nitrate (NO _x ) level correlates with biomarkers that are known components of the metabolic syndrome (MetS). Methods Serum NO _x levels were measured using a commercial kit in 608 Japanese men and women between the ages of 39 and 85 years. Multivariate adjustments for age, smoking status, alcohol consumption and exercise were made in the analysis of covariance (ANCOVA). The components of the metabolic syndrome were defined based on the following criteria: body mass index (BMI) ≥25.0 kg/m², glycated hemoglobin (HbA1c) ≥5.6%, systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg, high-density lipoprotein-cholesterol (HDL-C) ≤1.03 mmol/l for men and ≤1.29 mmol/l for women and triglyceride ≥1.69 mmol/l. Results The logarithmically transformed age-adjusted serum NO _x (lnNO _x ) value was significantly higher in the low HDL-C group (1.76 ± 0.05 μmol/l; p < 0.05) than MetS component groups (1.65 ± 0.01 μmol/l) in men, but no difference was found in women. The means of serum lnNO _x after multivariate adjustment were 1.64, 1.65, 1.64, 1.66, and 1.81 μmol/l for 0, 1, 2, 3, and 4–5 MetS components for all subjects, respectively. The results of ANCOVA confirmed that the serum lnNO _x level was significantly correlated with the clustering of MetS components in both men and women (p < 0.0001 for trend). Conclusion Our results suggest that an increase in the clustering of MetS components was associated with the increase in serum NO levels in our general population.     

In vitro and in vivo anti-tumour effects of a humanised monoclonal antibody against c-erbB-2 product.

The c-erbB-2 product is thought to be a unique and useful target for antibody therapy of cancers overexpressing the c-erbB-2 gene. In vitro and in vivo anti-tumour effects of a humanised antibody against the extracellular domain of the c-erbB-2 gene product, rhu4D5, were examined. Rhu4D5 was less effective than its murine counterpart, mu4D5, for the direct antiproliferative activity against the c-erbB-2-overexpressing SK-BR-3 cell line. In vivo treatment of severe combined immunodeficient (SCID) mice carrying the c-erbB-2-overexpressing 4-1ST human gastric carcinoma xenograft with 4hu4D5 revealed that the recombinant protein had potent anti-tumour activity. Furthermore, cytotoxicity of human peripheral blood mononuclear cells against 4-1ST was significantly augmented with rhu4D5, but not with mu4D5. These results indicate that rhu4D5 might perform better in patients than predicted from preclinical studies.     

Up-regulation of inositol 1, 4, 5-trisphosphate receptor expression in atrial tissue in patients with chronic atrial fibrillation

BACKGROUND: Abnormal intracellular Ca2+ homeostasis occurs in chronic atrial fibrillation(AF). The intracellular Ca2+ concentration is regulated by ryanodine and inositol 1,4,5-trisphosphate (IP3) receptors. Changes occur in ryanodine receptors in atrial tissue from patients in chronic AF. Whether AF patients have alterations in atrial IP3 receptors was investigated. METHODS: IP3 receptor expression was analyzed in the right atrial myocardium from 13 mitral valvular disease (MVD) patients with AF (MVD/AF), 5MVD patients with normal sinus rhythm(MVD/NSR), and 8 control patients with NSR(tissue obtained during coronary artery bypass surgery). Hemodynamic and echocardiographic data were obtained preoperatively, and an immunohistochemical study was performed on the atrial tissue. RESULTS: The relative expression level of IP3 receptor protein was significantly greater in MVD/AF (0.75 +/- 0.26) than in MVD/NSR (0.42 +/- 0.13, p < 0.01), and both were significantly above the control value (0.14 +/- 0.08). The relative expression level of IP3 receptor mRNA was significantly greater in MVD/AF(0.028 +/- 0.008) than in control subjects (0.015 +/- 0.004, p < 0.01), but MVD/AF patients did not differ from MVD/NSR (0.020 +/- 0.006) patients. The relative expression levels of IP3 receptor protein and mRNA were higher in patients with left atrial dimension > or = 40 mm, pulmonary capillary wedge pressure > or = 10 mmHg, and right atrial pressure > or = 5 mmHg. IP3 receptors were overexpressed in the cytosol and at the nuclear envelope of atrial myocytes in MVD. CONCLUSIONS: Since chronic mechanical overload of the atrial myocardium increases IP3 receptor expression, especially in patients with chronic AF, up-regulation of IP3 receptors may be important in modulating intracellular Ca2+ homeostasis and initiating and/or perpetuating AF.     

Differentiation- and apoptosis-inducing activities by pentacyclic triterpenes on a mouse melanoma cell line

In a study to investigate the relationship between the chemical structure and the differentiation-inducing activity of pentacyclic triterpenes, several lupane, oleanane, and ursane triterpenes were prepared and their effects on B16 2F2 melanoma cell differentiation and growth were examined. Eleven lupane triterpenes used in this study acted on the melanoma cells as a melanogen, but no induction of melanogenesis of B16 2F2 cells by oleanane and ursane was detected. The differences at C-17 of the lupane series and acetylation of the OH group at C-3 did not markedly influence their activities. However, the ED(50) value for up-regulation of melanin biosynthesis was markedly decreased by the oxidation of the OH group at C-3 of lupeol (1). Betulinic acid (11), its methyl ester (12), lup-28-al-20(29)-ene-3beta-ol (9), and lup-28-al-20(29)-en-3-one (10) inhibited B16 2F2 cell proliferation by induction of apoptosis. These findings suggested that the carbonyl group at C-17 might be essential for the apoptotic effects of these compounds on B16 2F2 cells.     

Tunicamycin inhibits NMDA and AMPA receptor responses independently of N-glycosylation

In a whole-cell patch-clamp configuration, currents through N-methyl- -aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor channels were monitored in cultured rat hippocampal neurons, and those currents were depressed to 25 and 28% of basal levels, respectively, by 3-min treatment with tunicamycin (10 μM), an inhibitor of protein N-glycosylation. Tunicamycin (10 μM) reduced amplitude of population spikes elicited in the dentate gyrus of rat hippocampal slices, reaching 78% of basal levels 60 min after the beginning of treatment, and long-term potentiation (LTP) of the perforant path was never induced in the presence of tunicamycin. Tunicamycin, thus, appears to serve as a modulator for NMDA and AMPA receptors, regardless of N-glycosylation, thereby inhibiting neurotransmission and LTP in the dentate gyrus.