Effects of mild and moderate hypothermia on apoptosis in neuronal PC12 cells.

BACKGROUND: There is still a possibility that mild hypothermic therapy may be useful as a neuroprotective tool during the intraoperative period, although the mechanism of cerebral protection by mild hypothermia is not well understood. We hypothesized that mild hypothermia may be protective against cerebral ischaemia by inhibiting post-ischaemia apoptosis. In this study, we used serum-deprived PC12 cells as the neuronal apoptotic model and examined the direct effects of mild and moderate hypothermia. METHODS: Apoptosis was induced by depriving the cell culture medium of serum, which is one of the most representative methods to induce apoptosis, but not necrosis, in PC12 cells. Effects of mild (35 and 33 degrees C) and moderate (31 and 29 degrees C) hypothermia on apoptosis were evaluated. Cytotoxicity (lactate dehydrogenase leakage) and the percentage of apoptotic cells (calculated by flow cytometry with propidium iodide) were evaluated 4 days after induction of apoptosis. As a control, cells without induction of apoptosis were incubated under the same conditions as the apoptosis group. RESULTS: Without induction at 37 degrees C, cytotoxicity and the percentage of apoptotic cells were over 60 and 90%, respectively. At each temperature examined below 35 degrees C, significant decreases in cytotoxicity and the percentage of apoptotic cells were observed. Mean cytotoxicity at 31 and 29 degrees C was 50.2 (SD 4.2)% and 47.9 (4.4)%, respectively. The percentage of apoptotic cells at 31 and 29 degrees C was 42.5 (7.4)% and 36.5 (7.3)%, respectively. In the control group, cytotoxicity and the percentage of apoptotic cells were significantly higher at 29 degrees C than at 37 degrees C. CONCLUSIONS: Mild and moderate hypothermia (29-35 degrees C) inhibited apoptosis, although hypothermia below 30 degrees C may induce apoptosis in intact cells.

A novel MPL point mutation resulting in thrombopoietin-independent activation.

Thrombopoietin (TPO) and its receptor (MPL) are important regulators of megakaryopoiesis. MPL belongs to a cytokine receptor superfamily. To date, all constitutively active MPL mutants have been artificially constructed with amino acid substitutions in the transmembrane domain or extracellular domain of the protein, and they activate signal transduction pathways in Ba/F3 cells that can also be activated by the normal MPL. In this paper, we report a novel spontaneously occurring mutation of MPL, with an amino acid substitution of Trp(508) to Ser(508) in the intracellular domain of MPL, that induces the factor-independent growth of Ba/F3 cells. Examination of intracellular signaling pathways demonstrated that the mutant MPL protein constitutively activates three distinct signaling pathways, SHC-Ras-Raf-MAPK/JNK, JAK-STAT, and PI3K-Akt-Bad.

Efficacy of the inflammatory cell infiltration inhibitor IS-741 on colitis induced by dextran sulfate sodium in the rat.

We examined the therapeutic effects of the inflammatory cell infiltration inhibitor IS-741 (N-(2-((ethylsulfonyl)amino)-5-(trifluoromethyl)-3-pyridinyl)-cyclohexanecarboxamide monosodium salt monohydrate) on a rat colitis model. As a result of its effects on leukocyte infiltration, IS-741 inhibits cell adhesion, alleviates symptoms and signs of pancreatitis and multiple organ failure and demonstrates a life-saving effect in a model of severe acute pancreatitis. A rat model was prepared by inducing colitis with 3% dextran sodium sulfate (DSS) and maintaining pathology with 1% DSS. Repeated oral administration of IS-741 at 1, 10 or 100 mg/kg per day was conducted for 2 weeks (during treatment with 1% DSS). IS-741 at each dose decreased the area of erosion in the large intestine, thickening of the wall of the large intestine and anemia caused by melena. Some effects of IS-741 were nearly equivalent to those of the control compound salazosulfapyridine. Furthermore, IS-741 markedly alleviated inflammatory cell infiltration into the intestinal wall. IS-741 improved lesions in a rat DSS model by inhibiting leukocyte infiltration, suggesting the possibility of clinical application of this drug for IBD.

Overexpression of lipoprotein lipase in transgenic rabbits inhibits diet-induced hypercholesterolemia and atherosclerosis.

Lipoprotein lipase (LPL) is a key enzyme in the hydrolysis of TG-rich lipoproteins. To elucidate the physiological roles of LPL in lipid and lipoprotein metabolism, we generated transgenic rabbits expressing human LPL. In postheparinized plasma of transgenic rabbits, the human LPL protein levels were about 650 ng/ml, and LPL enzymatic activity was found at levels up to 4-fold greater than that in nontransgenic littermates. Increased LPL activity in transgenic rabbits was associated with as much as an 80% decrease in plasma triglycerides and a 59% decrease in high density lipoprotein-cholesterol. Analysis of the lipoprotein density fractions revealed that increased expression of the LPL transgene resulted in a remarkable reduction in the level of very low density lipoproteins as well as in the level of intermediate density lipoproteins. In addition, LDL cholesterol levels in transgenic rabbits were significantly increased. When transgenic rabbits were fed a cholesterol-rich diet, the development of hypercholesterolemia and aortic atherosclerosis was dramatically suppressed in transgenic rabbits. These results demonstrate that systemically increased LPL activity functions in the metabolism of all classes of lipoproteins, thereby playing a crucial role in plasma triglyceride hydrolysis and lipoprotein conversion, and that overexpression of LPL protects against diet-induced hypercholesterolemia and atherosclerosis.

[Asystole during electroconvulsive therapy in a patient with depression and myasthenia gravis].

A 44-yr-old woman presented with major depression. She was scheduled to receive electroconvulsive therapy under anesthetic care because of drug-induced leukopenia. Her significant past medical history was myasthenia gravis. She had been treated with thymectomy and pyridostigmine. She showed no evidence of muscle weakness while receiving the medication. After preanesthetic assessment, pyridostigmine was continued and routine anesthetics were chosen. Under 100% oxygen inhalation, thiamylal and suxamethonium were administered intravenously. Alternate current was delivered for 5 seconds, which induced seizure satisfactorily. However, asystole lasted for 10 seconds during the procedure. Spontaneous beating appeared followed by tachycardia and bigemina. Normal sinus rhythm returned four minutes later. She recovered smoothly, and showed no evidence of confusion nor muscle weakness. We speculated that pyridostigmine potentiated the ECT-induced vagal reflex and provoked asystole. In the following session, we pretreated her with intravenous atropine prior to thiamylal and suxamethonium. Although the current delivery increased RR-interval up to 1.2 seconds, neither asystole nor serious tachyarrhythmia occurred. Seven sessions of ECT relieved her psychiatric symptoms uneventfully. We presented a case of depression for which ECT was applied. Asystole with ECT seems associated with administration of pyridostigmine for the treatment of myasthenia gravis. Pretreatment with atropine can prevent asystole without inducing hazardous tachyarrhythmia.

YM-53601, a novel squalene synthase inhibitor, reduces plasma cholesterol and triglyceride levels in several animal species.

The aim of this study was to evaluate the potency of YM-53601 ((E)-2-[2-fluoro-2-(quinuclidin-3-ylidene) ethoxy]-9H-carbazole monohydrochloride), a new inhibitor of squalene synthase, in reducing both plasma cholesterol and triglyceride levels, compared with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor and fibrates, respectively. YM-53601 equally inhibited squalene synthase activities in hepatic microsomes prepared from several animal species and also suppressed cholesterol biosynthesis in rats (ED(50), 32 mg kg(-1)). In guinea-pigs, YM-53601 and pravastatin reduced plasma nonHDL-C (=total cholesterol - high density lipoprotein cholesterol) by 47% (P<0.001) and 33% (P<0.001), respectively (100 mg kg(-1), daily for 14 days). In rhesus monkeys, YM-53601 decreased plasma nonHDL-C by 37% (50 mg kg(-1), twice daily for 21 days, P<0.01), whereas the HMG-CoA reductase inhibitor, pravastatin, failed to do (25 mg kg(-1), twice daily for 28 days). YM-53601 caused plasma triglyceride reduction in hamsters fed a normal diet (81% decrease at 50 mg kg(-1), daily for 5 days, P<0.001). In hamsters fed a high-fat diet, the ability of YM-53601 to lower triglyceride (by 73%, P<0.001) was superior to that of fenofibrate (by 53%, P<0.001), the most potent fibrate (dosage of each drug: 100 mg kg(-1), daily for 7 days). This is the first report that a squalene synthase inhibitor is superior to an HMG-CoA reductase inhibitor in lowering plasma nonHDL-C level in rhesus monkeys and is superior to a fibrate in significantly lowering plasma triglyceride level. YM-53601 may therefore prove useful in treating hypercholesterolemia and hypertriglyceridemia in humans.

Pentobarbital inhibits apoptosis in neuronal cells.

OBJECTIVE: Previous reports have demonstrated that barbiturates have a protective effect against cerebral ischemia, although the mechanisms are incompletely understood. Recently, it has been suggested that apoptosis is involved in ischemic neuronal death. This study examined the effect of pentobarbital on neuronal apoptosis. DESIGN: Randomized, controlled, prospective study. SETTING: University research laboratory. SUBJECTS: PC12 cells derived from rat pheochromocytoma as a model of neuronal tissue. INTERVENTIONS: Apoptosis was induced by depriving serum from the cell culture medium. Effect of pentobarbital (0.5, 5, 50 microg/mL) was evaluated. MEASUREMENTS AND MAIN RESULTS: First, electrophoresis of DNA and fluorescence microscopic examination were performed to ascertain whether apoptosis was really induced after serum deprivation in our cells. Second, the effect of pentobarbital on cytotoxicity (evaluated by a leakage assay of lactic dehydrogenase) was evaluated. Third, the percentage of apoptotic cells was calculated by measuring cellular DNA content with flow cytometry. Calculation of the percentage of apoptotic cells was based on cumulative frequency curves of the appropriate DNA histograms. DNA electrophoresis exhibited a typical ladder pattern from the first day after the induction of apoptosis. The cells with chromatin condensation and/or fragmentation increased day by day after depriving serum in fluorescence microscopic examination. Four days after the induction of apoptosis, cytotoxicity without pentobarbital was 53.9 +/- 24.3% (mean +/- SD). Pentobarbital significantly inhibited cell death in a dose-dependent fashion. The percentage of apoptotic cells without pentobarbital was 94.9 +/- 6.3% 4 days after the induction of apoptosis. The treatment with 50 microg/mL pentobarbital significantly decreased the percentage of apoptotic cells to 61.8 +/- 21.3%. CONCLUSIONS: Our data indicate that pentobarbital inhibits apoptosis induced by serum deprivation in PC12 cells.

The effect of calcium channel blockers on cerebral oxygenation during tracheal extubation.

UNLABELLED: Calcium channel blockers are effective in stabilizing systemic hemodynamics during tracheal extubation. However, they may increase cerebral blood flow (CBF) during tracheal extubation because of cerebral vasodilation, even if systemic arterial blood pressure decreases. In this study, we observed changes in cerebral oxygenation during tracheal extubation by using near-infrared spectroscopy and evaluated the effect of nicardipine and diltiazem on the resultant changes. We studied 45 women undergoing elective gynecologic surgery. After surgery, the patients were randomly allocated to three groups (n = 15 each): saline (control), 0.02 mg/kg nicardipine, and 0.2 mg/kg diltiazem. After 2 min, we started to aspirate secretions for 2 min and then, extubated the trachea. Changes in cerebral oxygenated hemoglobin (HbO(2)) and deoxygenated hemoglobin were measured during the extubation procedure for 9 min after drug treatment. Systemic hemodynamics, including mean arterial blood pressure, heart rate, end-tidal CO(2), end-tidal sevoflurane concentration, and peripheral arterial oxygen saturation were also monitored. During extubation, HbO(2) increased significantly, presumably caused by the increase in CBF. Changes in deoxygenated hemoglobin were minimal. Compared with the control, nicardipine and diltiazem significantly inhibited the increase in mean arterial blood pressure. On the contrary, they significantly enhanced the increase in HbO(2). In conclusion, calcium channel blockers may increase CBF during extubation, even if these drugs stabilize systemic hemodynamics. IMPLICATIONS: This study is a preliminary report evaluating the changes in cerebral oxygenation during the tracheal extubation. Cerebral oxygenated hemoglobin increased significantly, presumably caused by the increase in cerebral blood flow during extubation. In addition, these changes were enhanced by calcium channel blockers.

The novel hypoglycemic agent YM440 normalizes hyperglycemia without changing body fat weight in diabetic db/db mice.

To determine the relationship between hypoglycemic activity and body weight gain induced by insulin sensitizers, we compared the effects of thiazolidinedione analogs (troglitazone and pioglitazone) and the oxadiazolidinedione analog (Z)-1,4-bis4[(3,5-dioxo-1,2,4-oxadiazolidin-2-yl)methyl]phen oxy¿but-2-ene (YM440) in diabetic db/db mice. Oral treatment with YM440(100 mg/kg) for 28 days decreased the blood glucose concentration (control v YM440, 418 +/- 12 v243 +/- 44 mg/dL). The hypoglycemic activity of this agent was comparable to that of troglitazone (300 mg/kg) and pioglitazone (100 mg/kg). There were no changes in food intake among the groups. Troglitazone and pioglitazone, but not YM440, significantly increased body weight gain during treatment (control, 7.2 +/- 0.5 g; YM440, 7.5 +/- 0.8 g; troglitazone, 10.9 +/- 0.8 g; and pioglitazone, 14.5 +/- 1.1 g). To further assess whether the increase in body weight by troglitazone or pioglitazone was due to adipogenesis, the weight of intraabdominal fat tissue (epididymal, retroperitoneal, and perirenal) was determined. There were no differences in the total weight of visceral fat between the control and YM440 treatment (3.53 +/- 0.23 and 3.60 +/- 0.16 g). In contrast, troglitazone and pioglitazone significantly increased the fat weight (4.31 +/- 0.13 and 4.66 +/- 0.19 g). Thiazolidinediones are known as ligands for peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor responsible for adipogenesis. Troglitazone and pioglitazone activated PPARgamma and increased triglyceride accumulation and mRNA expression of fatty acid-binding protein (FABP) in 3T3-L1 cells. However, YM440 had no effect on these indices for adipocyte differentiation. These results suggest that the mechanism is different for the hypoglycemic action of YM440 versus the thiazolidinediones. YM440 ameliorates hyperglycemia without changing PPARgamma activity, adipocyte differentiation, or fat weight. Thus, YM440 could be a useful hypoglycemic agent for the treatment of non-insulin-dependent diabetes mellitus (NIDDM) without affecting body weight.

Homodimer of two F-box proteins betaTrCP1 or betaTrCP2 binds to IkappaBalpha for signal-dependent ubiquitination.

We found previously that overexpression of an F-box protein betaTrCP1 and the structurally related betaTrCP2 augments ubiquitination of phosphorylated IkappaBalpha (pIkappaBalpha) induced by tumor necrosis factor-alpha (TNF-alpha), but the relationship of the two homologous betaTrCP proteins remains unknown. Herein we reveal that deletion mutants of betaTrCP1 and betaTrCP2 lacking the F-box domain suppressed ubiquitination and destruction of pIkappaBalpha as well as transcriptional activation of NF-kappaB. The ectopically expressed betaTrCP1 and betaTrCP2 formed both homodimer and heterodimer complexes without displaying the trimer complex. Dimerization of betaTrCP1 and/or betaTrCP2 takes place at their conserved NH(2)-terminal regions, termed a "D-domain" (for dimerization domain), located upstream of the F-box domain. The D-domain was necessary and sufficient for the dimer formation. Intriguingly, the betaTrCP homodimer, but not the heterodimer, was selectively recruited to pIkappaBalpha induced by TNF-alpha. These results indicate that not only betaTrCP1 but also betaTrCP2 participates in the ubiquitination-dependent destruction of IkappaBalpha by forming SCF(betaTrCP1-betaTrCP1) and SCF(betaTrCP2-betaTrCP2) ubiquitin-ligase complexes.

Morphometric evidence that YM175, a bisphosphonate, reduces trabecular bone resorption in ovariectomized dogs with dietary calcium restriction.

We examined mechanisms by which incadronate disodium (YM175) prevented bone resorption in ovariectomized dogs with dietary calcium restriction using the morphometrical method. YM175 (0.01-1.0 mg/kg) was given to ovariectomized dogs for 18 months. Because lumbar bone mineral density remained constant at month 17, we assumed that the trabecular bone resorption rate was equal to the bone formation rate and that wall thickness equaled resorption cavity depth. YM175 decreased both the bone resorption rate per number of osteoclasts and resorption cavity depth of cancellous pockets which were increased in ovariectomized dogs. These results suggest that YM175 reduces bone loss by decreasing the resorbing activity of osteoclasts.

YM116, 2-(1H-imidazol-4-ylmethyl)-9H-carbazole, decreases adrenal androgen synthesis by inhibiting C17-20 lyase activity in NCI-H295 human adrenocortical carcinoma cells.

The concentrations of androstenedione and dehydroepiandrosterone, products of C17-20 lyase, in the medium after a 6-hr incubation of NCI-H295 cells were decreased by YM116 (2-(1H-imidazol-4-ylmethyl)-9H-carbazole) (IC50: 3.6 and 2.1 nM) and ketoconazole (IC50: 54.9 and 54.2 nM). 17Alpha-hydroxyprogesterone, a product of 17alpha-hydroxylase, was increased by YM116 (1-30 nM) and by ketoconazole (10-300 nM) and then was decreased at higher concentrations of both agents (IC50: 180 nM for YM116, 906 nM for ketoconazole), indicating that YM116 and ketoconazole were 50- and 16.5-fold more specific inhibitors of C17-20 lyase, respectively, than 17alpha-hydroxylase. Compatible with these findings, progesterone, a substrate of 17alpha-hydroxylase, was increased by these agents. Cortisol production was inhibited by YM116 and ketoconazole (IC50: 50.4 and 80.9 nM, respectively). YM116 was a 14-fold more potent inhibitor of androstenedione production than cortisol production, whereas ketoconazole was a nonselective inhibitor of the production of both steroids. YM116 and ketoconazole inhibited the C17-20 lyase activity in human testicular microsomes (IC50: 4.2 and 17 nM, respectively). These results demonstrate that YM116 reduces the synthesis of adrenal androgens by preferentially inhibiting C17-20 lyase activity.

Assembly of lipoprotein (a) in transgenic rabbits expressing human apolipoprotein (a).

The study of human lipoprotein (a) [Lp(a)] has been hampered due to the lack of appropriate animal models since apolipoprotein (a) [apo(a)] is found only in primates and humans. In addition, human apo(a) in transgenic mice can not bind to murine apoB to form Lp(a) particles. In this study, we generated three independent transgenic rabbits expressing human apo(a) in their plasma at 1.8-4.5 mg/dl. In the plasma of transgenic rabbits, unlike the plasma of transgenic mice, about 80% of the apo(a) was covalently associated with rabbit apo-B and was contained in the fractions with density 1.02-1.10 g/ml, indicating the formation of Lp(a). These results suggest that transgenic rabbits expressing human apo(a) exhibit efficient assembly of Lp(a) and can be used as an animal model for the study of human Lp(a).

Effect of IS-741 on cell adhesion between human umbilical vein endothelial cells and HL-60 cells.

The effect of IS-741 (N-[(2-ethylsulfonylamino)-5-trifluoromethyl-3-pyridyl] cyclohexanecarboxamide monohydrate) on a model for pancreatitis has been previously reported. Recent patho-histological observations of remedial tests using rats found that the IS-741 administered group showed a low degree of tissue infiltration by inflammatory cells (polymorphonuclear leukocytes). We therefore examined cell adhesion, which is the first step in tissue infiltration by activated neutrophils, and investigated the effect of IS-741 on cell adhesion between human umbilical vein endothelial cells (HUVEC) and human promyelo-leukemia cell line (HL-60) cells during lipopolysaccharide stimulation in vitro. IS-741 significantly inhibited the adhesion of HL-60 cells to HUVEC. Further investigation of IS-741 on individual cells revealed that IS-741 mainly affected HL-60 cells. Investigation of the inhibitory effect of IS-741 at the molecular level (targeting adhesion molecules) also revealed that IS-741 had no effect on the appearance of endothelial leukocyte adhesion molecule-1 (ELAM-1), intercellular adhesion molecule-1 (ICAM-1) or vascular cell adhesion molecule-1 (VCAM-1) on HUVEC, which supports the theory that IS-741 is mainly effective on HL-60 cells, even at the molecular level. However, the inhibition of adhesion was noticed in experiments in which an anti-ICAM-1 or anti-VCAM-1 antibody was added to the adhesion test system. Therefore, IS-741 is likely to affect adhesion molecules which belong to the beta1 or beta2 integrin family.

A novel synthetic anti-acute pancreatitis agent, IS-741.

A novel synthetic drug, IS-741, inhibited cell adhesion in vitro and neutrophil in vivo. Thus, IS-741 inhibited the magnification of pancreatic lesion as well as progression to multiple organ failure in acute pancreatitis models. Furthermore, IS-741 at identical plasma concentrations equally improved the survival rates in animals of various species with severe acute pancreatitis. Based on these observations, it was considered that IS-741 inhibited tissue destruction by neutrophil after inhibiting neutrophil infiltration into the pancreas or other important organs in acute pancreatitis. It was also considered that IS-741 demonstrated various anti-acute pancreatitis effects by interrupting a vicious cycle of inflammation. Therefore, IS-741 is expected to become a useful drug for treating acute pancreatitis and multiple organ failure in clinical settings.

YM268 increases the glucose uptake, cell differentiation, and mRNA expression of glucose transporter in 3T3-L1 adipocytes.

The purpose of this study was to examine the effects of bis[4-[2,4-dioxo-5-thiazolidinyl)methyl]phenyl]methane (YM-268), a thiazolidinedione derivative, on glucose uptake, adipocyte differentiation through peroxisome proliferator-activated receptor gamma(PPARgamma), and phosphatidylinositol 3-kinase (PI 3-kinase) activity in cultured cells. YM268 and pioglitazone dose-dependently increased the 2-deoxyglucose uptake in 3T3-L1 cells. YM268 facilitated the insulin-stimulated triglyceride accumulation in 3T3-L1 adipocytes and increased the mRNA expression of fatty acid-binding protein. YM268, with and without insulin, increased the mRNA expression of glucose transporter isoforms such as GLUT1 and GLUT4, indicating enhancement of adipocyte differentiation. Additionally, YM268 and pioglitazone showed activity of the PPARgamma ligand, a member of the nuclear receptor superfamily responsible for adipogenesis. To examine the possible involvement of the increased activity of PI 3-kinase in YM268-stimulated glucose uptake, the enzyme activity was estimated by measuring the phosphatidylinositol-3,4,5-trisphosphate (PI-3,4,5-P3) concentration in human monocytic cells. Insulin dose-dependently increased the PI-3,4,5-P3 production but YM268 had no significant effect on the insulin-dependent and -independent PI 3-kinase activation. These results indicate that the mechanism by which YM268 increased glucose uptake, may be accounted for in part by the enhancement of GLUT1 and GLUT4 expression through PPARgamma activation.

In vivo effects of pioglitazone on uncoupling protein-2 and -3 mRNA levels in skeletal muscle of hyperglycemic KK mice.

Pioglitazone is a thiazolidinedione drug (TZD) which potently and specifically stimulates peroxisome proliferator-activated receptor gamma (PPAR gamma) and sensitizes cells to insulin. Since TZDs are thought to increase energy expenditure, changes in mitochondrial thermogenesis uncoupling protein-2 and -3 mRNA levels in response to pioglitazone treatment were measured in mouse skeletal muscle. Normally hyperglycemic and hyperinsulinemic KK/Ta mice were given pioglitazone for 2 weeks to treat this non-insulin dependent diabetes-like condition. During treatment, UCP2 mRNA levels increased to 185% of normal untreated control levels in soleus muscle. In contrast, UCP3 mRNA levels significantly decreased, up to 67% of normal untreated control levels. Interestingly, UCP3 mRNA levels correlated quite strongly with blood glucose levels, with r = 0.82 for gastrocnemius tissue and r = 0.92 for soleus tissue. These results may indicate that pioglitazone increases glucose catabolism by direct upregulation of muscle UCP2 gene expression in vivo. Therefore, UCP3 gene expression is controlled by a different mechanism than UCP2 expression.

Inhibitory effects of YM175, a bisphosphonate, on the progression of experimental periodontitis in beagle dogs.

This study examined the efficacy of YM175 [disodium dihydrogen (cycloheptylamino) methylene-1, 1-bisphosphonate] in reducing alveolar bone loss caused by experimental periodontitis in beagle dogs. Thirty-six dogs were used and divided into 6 groups. Periodontitis was induced in 30 dogs (groups 2-6) by ligating the bilateral mandibular third and fourth premolar teeth with silk ligatures and by feeding a soft diet. Six dogs were sham-operated (group 1). Saline (placebo), flurbiprofen (0.02 mg/kg) and YM175 (0.01, 0.1 and 1.0 mg/kg) were administered to the dogs (groups 2-6) 5 d/wk for 25 wk. Radiographic and morphometric analyses were performed. In placebo-treated animals (group 2), the ligation caused a significant decrease in the alveolar bone height by 0.57 and 1.91 mm at 2 and 25 wk, respectively. YM175 (1.0 mg/kg) prevented the decrease in bone height by 47 and 31% at 2 and 25 wk. YM175 (0.1 mg/kg) and flurbiprofen tended to prevent bone loss after 15 wk. Although the ligation elicited no significant change in bone mineral density, it significantly decreased bone volume. YM175 (1.0 mg/kg) and flurbiprofen tended to increase the bone volume. The number of formative or resorptive Haversian canals and the bone turnover through the periosteal bone surface were increased by the ligation, indicating the increased turnover of the cortical bone. YM175 (1.0 mg/kg) reduced the increased bone turnover. The gingival index was maximally increased at 2 wk and was suppressed by YM175. These results suggest that YM175 prevents alveolar bone loss by reducing the increased alveolar bone turnover in dogs with periodontitis.

Novel nonsteroidal inhibitor of cytochrome P450(17alpha) (17alpha-hydroxylase/C17-20 lyase), YM116, decreased prostatic weights by reducing serum concentrations of testosterone and adrenal androgens in rats.

BACKGROUND: The purpose of this study was to determine the effects of a nonsteroidal C17-20 lyase inhibitor, 2-(1H-imidazol-4-ylmethyl)-9H-carbazole (YM116), on serum concentrations of androgens and ventral prostatic weight in rats. METHODS: Serum concentrations of testosterone and of dehydroepiandrosterone sulfate and prostatic weights were measured in rats treated with YM116. RESULTS: YM116 inhibited testicular C17-20 lyase competitively (Ki, 0.38 nM), and decreased the serum testosterone concentration in gonadotropin-releasing hormone-treated rats (ED50, 0.7 mg/kg), indicating that YM116 was about 21-24 times more potent than other C17-20 lyase inhibitors such as ketoconazole and liarozole, and was twice as potent as CB7630. YM116 also reduced dehydroepiandrosterone sulfate levels in ACTH-treated castrated rats (ED50, 11 mg/kg). YM116 (40 mg/kg, p.o., for 2 weeks) was almost comparable to bilateral orchiectomy with respect to the time course and magnitude of the reduction in prostatic weight. Each of these two treatments decreased the prostatic weight 3 days following the treatment. Contrarily, leuprolide transiently increased the prostatic weight and then decreased it. YM116 (100 mg/kg) had no effect on the serum cortisol level in guinea pigs, and slightly decreased the serum aldosterone level in rats. CONCLUSIONS: YM116 is a selective C17-20 lyase inhibitor which decreases rat prostatic weight by reducing androgen production in the testes and adrenal glands.

Increase of bone mass and mechanical strength in rats after treatment with a novel bisphosphonate, YM175, for two years.

We have evaluated the relationship between bone mass and mechanical properties of bone from male and female rats treated with YM175, a novel bisphosphonate, for 104 weeks. YM175 [disodium (cycloheptylamino) methylenediphosphonate monohydrate] was given via the drinking water at a concentration of 0, 0.005, 0.015, 0.05, or 0.15%. Since the mortality in the male 0.15% group exceeded the exclusion criteria (75%) at week 88, this-group was omitted from the study. Mean daily intake of YM175 was 2.2-22.1 mg/kg for males and 3.6-104 mg/kg for females. After the treatment, mechanical properties and ash weight of the humerus were determined. In males, 0.015 and 0.05% of YM175 (6.6-22.1 mg/kg) significantly increased failure load of the midshaft. In females, failure load and stiffness of the midshaft tended to be increased by YM175 (up to 104 mg/kg). Furthermore, ultimate compressive load at the humeral metaphysis treated with the highest dose of YM175 was 2- or 3.5-fold greater than that of untreated male or female control. Ash weight of the humerus was increased dose-dependently and was positively correlated with failure load of the midshaft. These findings indicate that treatment for 2 years with YM175 increased bone mass and mechanical strength without blocking bone mineralization.