Osteoclastogenesis inhibitory factor/osteoprotegerin reduced bone loss induced by mechanical unloading.

Skeletal unloading resulting from space flight and prolonged immobilization causes bone loss. Such bone loss ostensibly results from a rapid increase in bone resorption and subsequent sustained reduction in bone formation, but this mechanism remains unclear. Osteoclastogenesis inhibitory factor/osteoprotegerin (OCIF/OPG) is a recently identified potent inhibitor of osteoclast formation. We studied effects of OPG administration on tail-suspended growing rats to explore the therapeutic potential of OPG in the treatment and prevention of bone loss during mechanical unloading, such as that which occurs during space flight. Treatment with OPG in tail suspension increased the total bone mineral content (BMC g) of the tibia and femur and the total bone mineral density (BMD g/cm2) of the tibia. Moreover, treatment with OPG prevented reduction not only of BMC and BMD, but also of bone strength occurring through femoral diaphysis. Treatment with OPG in tail-suspended rats improved BMC, BMD and bone strength to levels of normally loaded rats treated with vehicle. Treatment with OPG in normally loaded rats significantly decreased urinary excretion of deoxypyridinoline, but the effect of OPG in tail suspension was unclear. These results indicate that OPG may be useful in inhibiting bone loss-engendered mechanical unloading.

Simultaneous measurements of temperature and pH in vivo using NMR in conjunction with TmDOTP5-.

NMR techniques for temperature and pH measurements have attracted increasing interest in recent years, motivated in part by the growing importance of medical hyperthermia for the treatment of cancer. The chemical shifts of thulium 1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetrakis(methylene phosphonate) (TmDOTP5-) have been studied as a function of temperature and pH. The results demonstrate that TmDOTP5- resonance shifts are highly sensitive to temperature (approximately 1.0 ppm/degrees C) and pH (approximately 3.2 ppm/pH unit) at clinically relevant field strengths. A new method is presented which utilizes two magnetically non-equivalent protons in TmDOTP5- for simultaneous NMR measurements of both temperature and pH. The difference in the chemical shift values of pairs of 1H resonances provides a temperature sensitivity of about 1.6 ppm/ degrees C. The technique is demonstrated in live rats undergoing ultrasound-induced hyperthermia therapy.

Identity of osteoclastogenesis inhibitory factor (OCIF) and osteoprotegerin (OPG): a mechanism by which OPG/OCIF inhibits osteoclastogenesis in vitro.

The morphogenesis and remodeling of bone depends on the integrated activity of osteoblasts that form bone and osteoclasts that resorb bone. We previously reported the isolation of a new cytokine termed osteoclastogenesis inhibitory factor, OCIF, which specifically inhibits osteoclast development. Here we report the cloning of a complementary DNA of human OCIF. OCIF is identical to osteoprotegerin (OPG), a soluble member of the tumor-necrosis factor receptor family that inhibits osteoclastogenesis. Recombinant human OPG/OCIF specifically acts on bone tissues and increases bone mineral density and bone volume associated with a decrease of active osteoclast number in normal rats. Osteoblasts or bone marrow-derived stromal cells support osteoclastogenesis through cell-to-cell interactions. A single class of high affinity binding sites for OPG/OCIF appears on a mouse stromal cell line, ST2, in response to 1,25-dihydroxyvitamin D3. An anti-OPG/OCIF antibody that blocks the binding abolishes the biological activity of OPG/OCIF. When the sites are blocked with OPG/OCIF, ST2 cells fail to support osteoclastogenesis. These results suggest that the sites are involved in cell-to-cell signaling between stromal cells and osteoclast progenitors and that OPG/OCIF inhibits osteoclastogenesis by interrupting the signaling through the sites.

Influence of cisapride on the pharmacokinetics and antihypertensive effect of sustained-release nifedipine.

To investigate the clinical significance of interactions between cisapride and sustained-release nifedipine, we compared the plasma nifedipine concentration and blood pressure after administration of nifedipine alone (20 mg) with those obtained after administration of nifedipine cisapride (2.5 mg) in 20 patients with hypertension. The plasma nifedipine level was not altered by cisapride at one hour after administration, but was significantly increased at two (p < 0.01), three (p < 0.01), and four (p < 0.05) hours when compared with the level measured after nifedipine alone. Cisapride significantly decreased the mean blood pressure at three hours (p < 0.05) after administration of nifedipine. The acetaminophen method was used to determine gastric emptying time. The plasma concentration of acetaminophen at 45 minutes after administration was significantly increased by cisapride, suggesting that enhanced gastrointestinal motility might be the basis for the increase in the plasma nifedipine concentration. These results suggest that enhancement of the antihypertensive effect of nifedipine can occur when the drug is prescribed with cisapride, and that caution is needed when using such a combination therapy.

Therapeutic effect of egualen sodium (KT1-32), a new antiulcer agent, on chronic gastritis induced by sodium taurocholate in rats.

We investigated the therapeutic effects of egualen sodium (KT1-32), a new antiulcer agent, on chronic erosive and atrophic gastritis induced by 5 months' administration of sodium taurocholate (TCA; 5 mM) in rats. The chronic gastritis was manifested by mucosal surface injuries (erosions), reduced mucosal thickness, reduction of the number of parietal cells, infiltration of inflammatory cells, and proliferation of collagenous fiber. Egualen sodium, (10-100 mg/kg, t.i.d.) administered orally to the rats for 2 weeks after the withdrawal of TCA, dose-dependently and significantly decreased the total length of erosions. The indicators of atrophic gastritis, i.e., reduced mucosal thickness and reduction in the number of parietal cells, were improved dose-dependently by the administration of this agent. Egualen sodium also reduced the inflammatory cell infiltration and the proliferation of collagenous fiber in the gastric mucosa in a dose-dependent manner. The reduced staining of neutral gastric mucus was improved by a high dose (100 mg/kg) of egualen sodium. The therapeutic effects of egualen sodium on experimental gastritis were superior to those of sofalcone and sodium guaiazulene 3-sulfonate. These results suggest that egualen sodium may be a promising agent for the treatment of erosive and atrophic gastritis.

Molecular cloning and functional expression of a cDNA encoding the human V1b vasopressin receptor.

Arginine vasopressin modulates the release of adrenocorticotropic hormone, beta-endorphin, and prolactin from the anterior pituitary. Release is mediated by the V1b receptor through the mobilization of intracellular Ca2+ by phosphatidylinositol hydrolysis. In contrast to its well characterized peripheral actions, such as antidiuresis, contraction of vascular smooth muscle, and stimulation of hepatic glycogenolysis, the exact site and mechanism of vasopressin action in the pituitary remain unclear. This is largely due to a lack of information on the molecular identity and exact localization of the V1b receptor. This lack prompted us to try to isolate this receptor subtype. Here we report the molecular cloning and functional expression of a complementary DNA encoding the human V1b receptor. The deduced 424-amino acid sequence of the receptor has highest overall homology with the V1a, V2, and oxytocin receptors, with homologies of 45, 39, and 45%, respectively. The receptor expressed in COS-1 cells has a single binding site for arginine vasopressin with a Kd of 0.17 +/- 0.04 nM. It binds various agonists and antagonists of vasopressin with affinities distinct from those of V1a and V2 receptors but consistent with those anticipated for the V1b receptor on the basis of the pharmacological studies. Furthermore, arginine vasopressin evoked calcium-dependent chloride current in Xenopus oocytes transfected with the receptor, which was not affected by a V1a/V2 antagonist. In contrast, the current evoked in oocytes transfected with V1a receptor was abolished by the antagonist. Northern blot analysis revealed that the receptor expression is restricted to the pituitary. These data clearly indicate that the cloned cDNA encodes the V1b receptor.

Effects of a Single Large Dose of Ethanol on Tissue Ascorbic Acid, Drug-Metabolizing Enzymes in the Liver, and Serum and Liver Lipids in Rats Fed with a PCB-containing Diet.

The effects of a single administration of ethanol after feeding a PCB-containing diet on tissue ascorbic acid, drug-metabolizing enzymes in the liver, and serum and liver lipids of rats were investigated. Male Donryu and Wistar rats that had been fed on a 20% casein diet with or without 0.03% PCB were given a 5g/kg of body weight ethanol solution (25%, w/v) via a stomach tube, and then killed 16h after the intubation. Intake of the PCB-containing diet accelerated the disappearance of blood ethanol. Dietary PCB and a single dose of ethanol independently affected the tissue levels of ascorbic acid. The combined effect on hepatic aniline hydroxylase activity was additive or synergistic. A single dose of ethanol did not significantly affect the hepatic aminopyrine N-demethylase activity. In Donryu rats, the effects from feeding on a PCB-containing diet and those from a single dose of ethanol on serum lipids were almost additive. In Wistar rats, the effects of ethanol alone on lipids were not necessarily apparent, but the effects of ethanol after feeding with the PCB-containing diet were strongly enhanced. Ethanol alone hardly affected the liver lipids. Most lipids that were increased by PCB alone were significantly decreased or tended to be decreased by a single dose of ethanol. The serum levels of GOT and GPT were markedly increased by a single large dose of ethanol concomitant with the PCB-containing diet in both strains of rats; however, PCB alone or ethanol alone hardly changed the serum levels of GOT and GPT. These results indicate that the effects of a single large dose of ethanol on drug and lipid metabolism, and on the liver function were markedly modified by the intake of a PCB-containing diet.

Protective effect of probucol on ischemia-reperfusion arrhythmias in the rat heart.

OBJECTIVE: To evaluate the efficacy of probucol on ischemia-reperfusion injury in the isolated working rat heart. DESIGN: Twelve male Sprague-Dawley rats were divided into two groups: one was fed normal chow (group C) and the other was fed chow containing 1% probucol for four weeks (group P). Samples of heart organ and blood were then taken under anesthesia. Isolated hearts were perfused in a working heart model. After 5 mins of perfusion in aerobic conditions, global ischemia was induced for 15 mins, the hearts were then reperfused. Aortic and coronary flow, cardiac function and electrocardiogram were monitored throughout the experiment, including a 20 min period of reperfusion. Serum lipids and lipid peroxide were also measured in each rat. RESULTS: Rats in group P (probucol-treated) had significantly lower levels of serum cholesterol, triglyceride and phospholipid than those in group C (controls). Serum lipid peroxide was also significantly lower in group P than in group C rats (P < 0.05). The incidence of ventricular arrhythmias in the ischemia and reperfusion stages was lower in group P than in group C (P < 0.001) and the increase in coronary flow during the reperfusion stage was greater in isolated hearts of group P rats than in those of group C (P < 0.05). CONCLUSIONS: Probucol may have a protective effect on myocardium with respect to ischemia-reperfusion arrhythmia in the isolated rat heart, presumably due to an antioxidative effect.

Short-term Effects of Ethanol Intoxication on Ascorbic Acid and Lipid Metabolism and on Drug-metabolizing Enzymes in Liver of Rats.

The effects of one-time ethanol intoxication on ascorbic acid and lipid metabolism and on drug-metabolizing enzymes in liver of rats were investigated. Male Donryu rats that had been fed semi-purified feed were given 5 g/kg ethanol solution (25%, w/v) via a stomach tube and killed 16 h after intubation. The amount of ascorbic acid excreted in the urine after ethanol administration increased, but renal and adrenal concentrations of ascorbic acid decreased. The serum levels of total cholesterol, high-density-lipoprotein cholesterol, triglycerides, phospholipids, and non-esterified fatty acids were elevated in rats given ethanol, but hepatic level of total lipids, cholesterol, triglycerides, phospholipids were not. The hepatic concentrations of cytochrome P-450 and cytochrome b5 did not increase, but this large dose of ethanol increased the activities of aminopyrine N-demethylase and cytochrome c reductase. These results indicated that the single dose of ethanol affected the ascorbic acid and lipid metabolism of rats, and induced drug-metabolizing enzymes in their liver.

[Healing promoting effect of azuletil sodium (KT1-32) on experimental chronic gastric ulcers and acceleration of healing in SPF environment].

We examined the healing promoting effects of azuletil sodium on acetic acid and clamping cortisone-induced gastric ulcer in rats. For the experiments on clamping-cortisone gastric ulcer, we used not only conventional rats in conventional conditions but also specific pathogen free (SPF) rats on SPF environment in order to prevent infection. The following results were obtained. 1) In acetic acid ulcer, azuletil sodium (AZE) (greater than or equal to 90 mg/kg/day, p.o.) significantly decreased ulcer index. As estimated on the basis of stage analysis (Ulcer, Healing, Scar), AZE (greater than or equal to 30 mg/kg/day, p.o.) significantly promoted the healing of ulcers. 2) In clamping cortisone ulcer (conventional), AZE (100 mg/kg/day, p.o.) significantly promoted the regeneration of blood vessels. 3) In clamping cortisone ulcer (SPF), AZE at greater than or equal to 30 mg/kg/day and 100 mg/kg/day significantly increased the healing index and mucosal regeneration index, respectively. 4) In clamping cortisone ulcer (SPF), the infection that was observed in the conventional test was not seen at all and the acceleration of healing was observed. Furthermore, the extent of adhesion was also reduced, and the standard errors of various healing indices were smaller. From these results, it is concluded that AZE accelerated the healing of experimentally-induced gastric ulcers in rats.

[Study of blood flow in hyperthermia using human renal cell carcinoma heterotransplanted in nude mice--differences in histological tumour pattern upon the effects of hyperthermia].

Utilizing two types of human renal cell carcinoma heterotransplanted in nude mice (JRC 1; papillary, avascular pattern, grade III, JRC 11; anaplastic and alveolar, hypervascular pattern, grade IV), we investigated the influence of tumor blood flow upon the effects of local hyperthermia (42.5 degrees C), induced by 915 MHz microwave. Blood flow was determined from the rate of thermal clearance by use of the bio-heat transfer equation. The rate of thermal clearance was measured at intervals of approximately 10 minutes throughout the treatment session after turning off the microwave for 50 seconds. With both strains it was necessary to increase the microwave power until the constant steady-state temperature of 42.5 degrees C was reached. The JRC 11 strain needed more power for the constant temperature than JRC 1, but it needed a greater decrease in power level during the heating session to maintain a constant steady-state temperature. This was an indication that the tumour blood flow decreased more markedly in the JRC 11 strain. In both tumours, a decrease of blood flow was observed during the heating session. In the case of the JRC 1 strain, it was observed that the mean value of blood flow was 1.87 times higher than that of JRC 11. This indicated a sharp reduction in blood flow in JRC 11 strain. This reduction was confirmed by the thermal clearance measurement at the end of the treatment session. A sharp reduction in blood flow in hypervascular tumour (JRC 11 strain) is caused by a stasis of intra-tumoural blood circulation during the heating.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of differences in tumor vascularity upon the effects of hyperthermia.

Utilizing two types of human renal carcinoma heterotransplanted in nude mice, we investigated the variations in hyperthermic effects (42.5 degrees C for 30 min) caused by differences in tumor type with special reference to variations in tumor vascularity. In the hypovascular JRC1 strain, sporadic vascular dilation was observed throughout the tumors after heating. Destruction of tumor cells was observed mainly in the region of dilation. In the hypervascular JRC11 strain, homogenous vascular dilation was observed immediately after heating, mainly at the periphery of tumors. There was a decrease in the viability of cells in the center of the tumor. Therefore, the hypervascular tumors showed greater destruction mainly at the center where blood circulation was reduced. The range of necrosis was also greatly affected by the extent of vascular dilation caused by heating in hypovascular tumors.

Effects of KT-362, a new Na and Ca influx and Ca release inhibitor, on canine ventricular arrhythmias.

Antiarrhythmic effects of the new drug KT-362, which was reported to suppress Na and Ca currents of cardiac cells and also to suppress intracellular Ca release in isolated smooth muscle preparations, were examined using two-stage coronary ligation-, digitalis- and adrenaline-induced ventricular arrhythmias in the dog. Intravenous KT-362 at 10 mg/kg suppressed coronary ligation arrhythmia both at 24 and 48 hr after ligation, and the minimum effective plasma concentrations for arrhythmias induced by 24 hr coronary ligation and 48 hr coronary ligation were 6.1 +/- 1.7 and 8.6 +/- 2.7 micrograms/ml, respectively. Antiarrhythmic effects were accompanied by transient hypotension. Oral administration of 70-100 mg/kg was also effective on 24 hr coronary ligation arrhythmia. However, there was no prominent hypotension in these experiments. Intravenous KT-362 at 3 mg/kg suppressed digitalis arrhythmia; and the minimum effective plasma concentration was 3.3 +/- 1.2 micrograms/ml, which was lower than the effective plasma concentrations for coronary ligation arrhythmias. Intravenous KT-362 at 1 mg/kg also suppressed adrenaline arrhythmia; and the minimum effective plasma concentration was 1.0 +/- 0.1 microgram/ml, the lowest among the effective plasma concentrations. These pharmacological profiles of KT-362 are quite different from those of class 4 Ca antagonists, but similar to those of class 1 drugs such as propafenone. Though KT-362 has a hypotensive effect, it is effective on canine ventricular arrhythmias; thus its clinical usefulness for supraventricular and ventricular arrhythmias is expected.

Hyperthermia with simultaneous administration of interferon using established human renal carcinoma heterotransplanted in nude mice.

Using human renal carcinoma heterotransplanted in nude mice, the effects of the combined use of hyperthermia and interferon (natural human interferon-alpha; IFN-alpha, and recombinant interferon-gamma; IFN-gamma) were examined. The hyperthermic device used was the Clini-Therm, Mark VII, 915 MHz, microwave. The administration of interferon was started immediately before hyperthermia and carried out on consecutive days. The combined use of hyperthermia and IFN was compared with hyperthermia and with IFN alone. The combined use of hyperthermia and IFN-alpha was shown to have significant anti-tumour effects compared with the former or latter alone. Of 10 nude mice (10 implanted tumours) used for the experiment, 5 showed complete disappearance of the implanted tumours and the others showed prolongation of survival. Combined treatment with IFN-gamma and hyperthermia showed no significant effect when compared with other treatment groups. Combined treatment with local hyperthermia and IFN-alpha may have some application to the clinical management of renal carcinoma.

Effect of dietary level of sulfur-containing amino acids on liver drug-metabolizing enzymes, serum cholesterol and urinary ascorbic acid in rats fed PCB.

Effects of dietary level of sulfur-containing amino acids (S-AA) on liver drug-metabolizing enzymes, serum cholesterol and ascorbic acid metabolism in growing rats fed diets containing 300 ppm of polychlorinated biphenyls (PCB) were investigated. Maximum gain in body weight was observed with 0.5% S-AA diets with or without PCB addition. Metabolic parameters increased by PCB were liver weight, activities of hepatic aminopyrine N-demethylase and aniline hydroxylase, serum total cholesterol, serum high density lipoprotein cholesterol, serum corticosterone and urinary metabolites of the glucuronic acid pathway including ascorbic acid, glucuronic acid and glucaric acid. In the PCB-treated animals, maximum values of liver weight, aminopyrine demethylase activity, serum cholesterol, serum corticosterone, urinary ascorbic acid and glucaric acid were obtained with about 0.8% S-AA. For the maximum induction of these metabolic responses, 0.5% S-AA was not enough. Urinary glucuronic acid and the ratio of lower density lipoprotein cholesterol versus high density lipoprotein cholesterol were decreased with a supplement of S-AA to PCB-containing diets.