Pharmacokinetics and safety of the novel amino-3-hydroxy-5-methylisoxazole-4-propionate receptor antagonist YM90K in healthy men

YM90K is a novel, selective and competitive alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor antagonist with neuroprotective properties, and it is currently under development for the intravenous treatment of stroke and other conditions of acute neuronal degeneration. The safety and pharmacokinetics of YM90K in healthy men was investigated after single doses up to 36 mg and repeated doses of 24 mg given by intravenous infusion over 3 hours. YM90K was well tolerated in healthy men and induced only mild changes in kidney function markers. Unchanged plasma drug concentration reached a near steady state during 3-hour infusion and rapidly decreased in a biphasic manner after the completion of infusion. YM90K showed linear pharmacokinetics. In the repeated-dose study, no significant differences were observed in pharmacokinetics of YM90K between the first and fifth dose. Unchanged urinary drug excretion was as high as 63.2% to 78.3% of the dose, most of which was excreted within 1 hour after the completion of infusion. YM90K is thought to be excreted mainly by renal tubular secretion. YM90K showed neither significant adverse reactions nor severe abnormalities in physical and laboratory examinations of the study participants and demonstrated safety and pharmacokinetic profiles compatible with clinical use.

Distribution of inhaled fluticasone propionate between human lung tissue and serum in vivo

High retention of inhaled glucocorticoids in the airways means prolonged anti-inflammatory action and low delivery into the serum. The objective of this study was to investigate the retention in and distribution of inhaled fluticasone propionate (FP) between central and peripheral human lung tissue and serum in vivo. In 17 patients undergoing lung resection surgery, a single 1.0 mg dose of FP was inhaled at varying time-points (range 2.8-21.7 h) preoperatively. Peripheral and central lung tissue was obtained, and blood was drawn simultaneously. FP concentrations in central lung tissue were approximately three to four times higher than peripheral lung tissue concentrations, which in turn, exceeded those found in serum by 10 times. FP was detectable up to 21 and 16 h, respectively, after inhalation, with drug levels falling almost in parallel in peripheral lung tissue and in serum. The results of this study demonstrate that fluticasone propionate is retained in lung tissue for a long time. Serum concentrations after a single inhaled dose are low. Retention of high concentrations of fluticasone propionate in the airways may promote high topical anti-inflammatory activity.

Clinical evaluation of a new formula of timolol maleate (WP-934 ophthalmic solution). WP-934 Study Group

We investigated the ocular hypotensive effect and possible adverse reactions of a new timolol maleate formula, WP-934 ophthalmic solution, which is timolol maleate solution dissolved in a reversible thermo-setting gel. Once-daily instillation of 0.25 or 0.5% WP-934 ophthalmic solution was administered in a prospective, randomized manner at 29 institutions for 8 weeks to patients with primary open-angle glaucoma or ocular hypertension, and for another 16 weeks in a limited number of these patients. Patients were closely monitored throughout the study by ophthalmic and systemic examinations, and by continuous evaluation of symptoms. The new timolol formula demonstrated a significant ocular hypotensive effect throughout the study period. Adverse effects were minor. WP-934 ophthalmic solution, timolol maleate dissolved in a reversible thermo-setting gel, has a significant ocular hypotensive effect in eyes with primary open-angle glaucoma and ocular hypertension.

Temporal changes in expression of transforming growth factor-beta superfamily members and their receptors during bovine preodontoblast differentiation in vitro

Transforming growth factor (TGF)-beta superfamily members and their receptors play a part in the differentiation of pulp cells into odontoblasts during reparative dentinogenesis. Bovine primary pulp-cell culture has been used as an in vitro model for proliferation and differentiation of pulp cells into preodontoblasts. To explore the molecular cascade of odontoblast differentiation, Northern blot analyses and reverse transcriptase polymerase chain reaction were here used to investigate the expression patterns of the genes for TGF-beta superfamily members: TGF-beta 1, namely bone morphogenetic protein (BMP)-4, BMP-7, activin-beta A and activin-beta B, and their type I and type II receptors, namely activin receptor-like kinase (ALK)-2 (ActR-I), ALK-3 (BMPR-IA), ALK-4 (ActR-IB), ALK-5 (T beta R-I), BMPR-II and T beta R-II, during differentiation of pulp cells into preodontoblasts in bovine adult pulp-cell culture. TGF-beta 1 and BMP-4 mRNAs were expressed from day 14 when matrix formation increased. BMP-7 mRNA was expressed only on day 28 when osteocalcin appeared. ALK-2 mRNA was increased from the beginning of the culture. ALK-3 and ALK-5 mRNAs first decreased on day 14 and increased again on day 21. T beta R-II and BMPR-II mRNAs were almost constant. These results suggest that the differentiation of pulp cells into preodontoblasts may be regulated by changes in the temporally coordinated expression pattern of TGF-beta superfamily members and their receptors, including up-regulation of transcription of TGF-beta 1, BMP-4, BMP-7, ALK-2, ALK-3, and ALK-5.

Antithrombotic effects in a rat model of aspirin-insensitive arterial thrombosis of desethyl KBT-3022, the main active metabolite of a new antiplatelet agent, KBT-3022

The antithrombotic effect of desethyl KBT-3022, which is the main active metabolite of the new antiplatelet agent, KBT-3022 (ethyl 2-[4,5-bis(4-methoxyphenyl)thiazol-2-yl] pyrrol-1-ylacetate; a cyclooxygenase inhibitor), was determined using a photochemically induced arterial thrombosis model in the rat femoral artery. Pretreatment with desethyl KBT-3022 (0.1, 0.3 and 1 mg/kg, i.v.) prolonged the time required to achieve thrombotic occlusion in the femoral artery and inhibited collagen-induced platelet aggregation in whole blood ex vivo, each in a dose-dependent manner. In all 6 rats used, particularly at the highest dose (1 mg/kg, i.v.) tested, cyclic variations in blood flow were hardly ever observed and complete cessation of blood flow did not occur during the 30-min observation time. BM-13505 (1, 3 and 10 mg/kg, i.v.), a thromboxane A2 receptor antagonist, also prolonged the time to occlusion, but cyclic variations in blood flow did occur. On the other hand, aspirin (10 and 30 mg/kg, i.v.) had little effect in terms of preventing thrombosis, although it inhibited collagen-induced platelet aggregation to the same extent as did desethyl KBT-3022. Desethyl KBT-3022 inhibited the thrombin-induced aggregation of washed platelets in a concentration-dependent manner (1-40 microM), whereas aspirin and BM-13505 did not. These findings suggest that the potent antithrombotic effect of desethyl KBT-3022 may be attributable in part to its additional ability to inhibit thrombin-induced platelet aggregation. Accordingly, thromboxane A2 and thrombin may be important thrombotic mediators in this rat model.

Pharmacokinetics and safety of JTP-4819, a novel specific orally active prolyl endopeptidase inhibitor, in healthy male volunteers

AIMS

To investigate the pharmacokinetics and safety profile of JTP-4819, (-)-(2S)-1-benzylaminocarbonyl-[(2S)-2-glycoloylpyrrolidinyl ]-2-pyrrolidinecarboxamide, a novel specific orally active prolyl endopeptidase (PEP) inhibitor.

METHODS

JTP-4819 was given orally to 28 healthy male volunteers at single doses of 30 mg (n = 6), 60 mg (n = 6), 120 mg (n = 6) and placebo (n = 3) and multiple doses of 60 mg three times daily (n = 5) and placebo (n = 2) for 7 days to investigate its safety and pharmacokinetics following a preliminary safety evaluation of 3, 10 and 30 mg doses in six healthy volunteers. With the single dose of 60 mg, a cross-over study was conducted to examine the effect of food on the bioavailability of the drug. The concentrations of JTP-4819 in plasma and urine were determined by electrospray ionization-liquid chromatography/mass spectrometry (ESI-LC/MS) method.

RESULTS

In the multiple-dose study, the cholinesterase activity was gradually increased and reached above the normal range on days 4 to 8 in all five subjects given JTP-4819 and gradually returned to normal range after completion of dosing. The elevation of plasma cholinesterase activity was considered to be an action of JTP-4819, but this remains to be verified. There were no other abnormal findings in objective symptoms and laboratory findings including blood pressure, heart rate, electrocardiogram, body temperature, haematology, blood chemistry and urinalysis. The Cmax of JTP-4819 at 30, 60 and 120 mg in fasting state were 474, 887 and 1,649 ng ml-1, respectively, at 1 h after administration, and the t1/2 was about 2 h. AUC increased in proportion to the given doses. The cumulative urinary recoveries within 24 h were approximately 66%, Cmax, AUC, t1/2 and urinary recovery were not affected by food intake. In the multiple-dose study, there was no drug accumulation trend in plasma.

CONCLUSIONS

These results indicate that JTP-4819 has acceptable pharmacodynamic and pharmacokinetics profiles for clinical use without any serious adverse events as we verified in healthy young male volunteers.

Optical recording of neural signals evoked by greater superficial petrosal nerve stimulation in rat

Electrical responses to greater superficial petrosal (GSP) nerve stimulation in a rat geniculate ganglion (GG) preparation were assessed by simultaneous multi-site-optical recording. The GG/GSP nerve preparations were dissected out and were stained with a voltage-sensitive dye (RH155). Application of depolarizing square pulses to the GSP nerve fibers using a suction electrode evoked optical (absorbance) signals that were recorded simultaneously from many contiguous regions using a 24 x 24 photodiode matrix array with 448 active elements. Those optical signals were observed along the left half area of the GSP nerve. As the distance from the site of stimulation increased, the optical signals appeared to conduct with increasing time-delay. From the relationship between the peak latency and distance, the conduction velocity was estimated to be about 0.4 m/s. Tetraethylammonium affected the duration of the optical signals, and the signals disappeared in solutions containing tetrodotoxin (TTX) or in Na(+)-deficient solutions. The optical signals evoked by the GSP nerve stimulation are considered to be due to the action potentials propagating along the GSP of unmyelinated axons.

A prospective, randomized, double-blind multicenter trial of a single bolus injection of the novel modified t-PA E6010 in the treatment of acute myocardial infarction: comparison with native t-PA. E6010 Study Group

OBJECTIVES

This prospective, randomized, double-blind multicenter trial evaluated the efficacy and safety of a single bolus injection of the novel modified tissue-type plasminogen activator (t-PA) E6010 in the treatment of acute myocardial infarction compared with that of native t-PA.

BACKGROUND

E6010 is a novel modified t-PA with a prolonged half-life (t1/2 alpha > or = 23 min) compared with native t-PA (t1/2 alpha = 4 min). E6010 can be administered in patients as a single intravenous bolus injection, and early recanalization can be expected.

METHODS

The efficacy of E6010 was compared with that of native t-PA in 199 patients with acute myocardial infarction who were treated within 6 h of onset in a prospective, randomized, double-blind multicenter trial. Patients were given either 0.22 mg/kg body weight of E6010 intravenously over 2 min or native t-PA (tisokinase) 28.8 mg or 14.4 million IU (10% of the total dose over 1 to 2 min, the remainder infused over 60 min).

RESULTS

The primary end point was the recanalization rate of the infarct-related coronary artery at 60 min after the start of treatment. Time to reperfusion was shorter in the E6010 group than in the native t-PA group. Thrombolysis in Myocardial Infarction flow grade 2 or 3 recanalization at 15, 30, 45 and 60 min after administration was observed in 37%, 62%, 74% and 79% (95% confidence interval [CI] 70% to 87%) of the E6010-treated patients and in 14%, 32%, 50% and 65% (95% CI 55% to 74%) of native t-PA-treated patients, respectively (p = 0.032 at 60 min).

CONCLUSIONS

The present study indicates that, compared with native t-PA, a single bolus injection of E6010 over 2 min produces a higher rate of early recanalization of the infarct-related coronary artery without fatal bleeding complications.

In vitro comparison between mouse B16 and human melanoma cell lines of the expression of ICAM-1 induced by cytokines and/or hyperthermia

The expression of intercellular adhesion molecule-1 (ICAM-1) in mouse B16 and human melanoma cell lines was investigated by indirect immunofluorescence using a FACScan analyzer. Mouse B16 melanoma cell lines (B16-F1 and F10) did not express ICAM-1 under ordinary culture conditions. Neither in vitro hyperthermia at 41 degrees C for 3 or 6 hr nor cytokines such as gamma interferon (IFN-gamma) or tumor necrosis factor alpha (TNF-alpha) induced ICAM-1 expression in B16 melanoma cell lines. A combination of IFN-gamma with TNF-alpha caused slight induction of ICAM-1 expression in the B16-F10 melanoma cell line. Hyperthermia at 41 degrees C for 3 hr in combination with the cytokines induced a slight expression of ICAM-1 in the B16-F1 melanoma cell line. Hyperthermia at 41 degrees C for 3 hr or 6 hr did not induce de novo ICAM-1 expression but hyperthermia at 43 degrees C for 6 hr caused rather suppression of the expression of ICAM-1 in the three human melanoma cell lines tested. In contrast, they showed a clear increase in the expression of ICAM-1 after treatment with either with IFN-gamma or TNF-alpha, and the expression was further augmented by a combination of the two cytokines. Treatment with cytokines in combination with hyperthermia at 41 degrees C or 43 degrees C for 3 hr did not augment the expression of ICAM-1 over that in cytokine-treated human melanoma cell lines, at normal temperatures. Thus, it is concluded that mouse B16-F1 and F10 melanoma cell lines are different from human melanoma cell lines in terms of induction of ICAM-1 expression by cytokines and/or hyperthermia.

Gastric cancer associated with overexpression of parathyroid hormone-related peptide (PTHrP) and PTH/PTHrP receptor in relation to tumor progression

Parathyroid hormone-related peptide (PTHrP) is involved in cell proliferation in both neoplastic and non-neoplastic tissues. We describe an autopsy case of gastric cancer in a patient who showed serum hypercalcemia and overexpression of PTHrP and PTH/PTHrP receptor in the metastatic tumor cells. The primary gastric tumor was poorly differentiated adenocarcinoma, and multiple metastases were present in the bone, multiple visceral organs, peritoneum, and lymph nodes. PTHrP and its mRNA were detected only in the metastatic tumor cells, but not in primary gastric tumor. PTH/PTHrP receptor was also demonstrated immunohistologically in metastatic tumor cells. This case suggests that the expression of PTHrP is related to tumor progression and the poor prognosis in tumors associated with humoral hypercalcemia.

Expression of parathyroid hormone-related peptide (PTHrP) in gastric tumours

Parathyroid hormone-related peptide (PTHrP) is produced by various neoplasms. It has been suggested that it acts as a cytokine for cell proliferation and tumour progression. The purpose of this study was to evaluate PTHrP expression in gastric cancers by immunohistochemistry. PTHrP was expressed in 71 of 92 (77.2 per cent) gastric adenocarcinomas without humoral hypercalcaemia. In contrast, one case (5 per cent) out of 20 adenomas and none of the background non-neoplastic epithelium showed PTHrP immunoreactivity. In carcinomas, PTHrP immunoreactivity was higher in moderately differentiated adenocarcinomas (21/22; 95-5 per cent) and poorly differentiated adenocarcinomas (34/34; 100 per cent) than in well-differentiated adenocarcinomas (10/23; 43 per cent). Furthermore, PTHrP expression was more intense in the deeply invasive portions than in the mucosal carcinomas. High percentages of metastatic tumour cells in regional lymph nodes were immunopositive. PTHrP mRNA expression was confirmed by in situ hybridization in gastric adenocarcinomas. Reverse transcription-polymerase chain reaction (RT-PCR) studies of normal gastric mucosa and four human gastric cancer cell lines detected PTHrP transcription in NUGC-1 (poorly differentiated) and NUGC-3 (poorly differentiated) but not in normal gastric mucosa, MKN-1 (well differentiated), and KATO-III (signet ring cell). These findings suggest that overexpression of PTHrP may be involved in the malignant transformation and progression of gastric carcinomas.

Aggregation of human blood platelets by remnant like lipoprotein particles of plasma chylomicrons and very low density lipoproteins

Remnant like lipoprotein particles (RLP) of partially catabolised human plasma chylomicrons (CM) and very low density lipoproteins (VLDL) were separated from CM and VLDL using two monoclonal antibodies, anti apo B-100 (JI-H) and anti apo A-I (H-12) coupled to Sepharose 4B gel to form an immunoaffinity column. Lipoproteins containing apo B-100 or apo E, including VLDL and LDL adsorb to (JI-H)-gel, while CM and HDL with apo A-I adsorb to (H-12)-gel. The unbound fraction (RLP) is rich in apo B-48, apo E and apo E rich apo B-100 which has not been recognized by JI-H. The RLP fraction with a total triglyceride of 12.35 +/- 6.22 mg/ml; total cholesterol, 0.32 +/- 0.08 mg/ml and total protein, 0.72 +/- 0.12 mg/ml (mean +/- S.E.M, n = 9) was added to blood from healthy persons at 2.5-200 microliters/ml and agitated gently at 37 degrees C for 40 s. Platelet aggregation was assessed by measuring the loss of single platelets. At 2.5-10 microliters, RLP induced platelet aggregation increased with the dose of RLP, but decreased at 25-200 microliters. Scanning electron microscopy revealed that within 20 s of agitation in the presence of RLP, activated platelets had appeared on the red cell membrane and within 40 s of agitation, platelet aggregates had formed on the red cells. The platelet responses were unaffected by aspirin (10 or 20 micrograms/ml) but were inhibited by cilostazol, a phosphodiesterase type III inhibitor (0.4 to 1.6 micrograms/ml). It is likely that the platelet effect of RLP is a consequence of RLP dependent red cell-platelet interaction. This is the first report of platelet aggregation induced by RLP without an added platelet agonist.

Inhibitory effect of prostaglandin E1 on intimal thickening following photochemically induced endothelial injury in the rat femoral artery

The inhibitory effect of prostaglandin E1, which has an anti-platelet action and a vasodilating action via intracellular cyclic AMP elevation, was studied on intimal thickening in the rat femoral artery. A segment of the femoral artery was occluded by a platelet and fibrin-rich thrombus due to photochemical reaction between systemically administered Rose Bengal and transluminal green light which causes endothelial injury followed by platelet adhesion and aggregation at the site of photochemical reaction. Three weeks after endothelial injury, intimal thickening occurred at the irradiated site. Prostaglandin E1 (0.3 microgram/kg per min), administered as a continuous infusion 10 min before photochemical reaction significantly (P < 0.05) prolonged the time to occlusion of the femoral artery. In a separate experiment, prostaglandin E1 (0.3 microgram/kg per min) administered as a continuous infusion for 7 days just after endothelial injury significantly (P < 0.05) inhibited intimal thickening compared with a control group. In cultured rat-derived vascular smooth muscle cells, prostaglandin E1 produced concentration-dependent inhibition of migration and proliferation, stimulated by platelet-derived growth factor. These results suggest that prostaglandin E1 may be effective in preventing vascular restenosis after vascular surgery and angioplasty.

Enhanced effect of triazolam with diltiazem

AIMS

Triazolam, a triazolobenzodiazepine hypnotic agent, is metabolized by CYP3A4. Diltiazem is an inhibitor of this isozyme. The aim of this study was to determine if diltiazem affects plasma concentrations of triazolam in humans.

METHODS

We investigated the interaction between triazolam and diltiazem in a randomized, three-phase crossover study. Seven healthy male volunteers received orally either a single 0.25 mg dose of triazolam, a 0.25 mg dose of triazolam after a 3-day treatment of diltiazem (180 mg day-1), or a placebo. Plasma samples were collected to determine triazolam concentration over a 24 h period. The pharmacodynamic effects of triazolam were investigated using the peak saccadic velocity of eye movements (PSV), electroencephalogram (EEG), and visual analogue scale (VAS) through 8 h.

RESULTS

Diltiazem pretreatment significantly increased the area under the triazolam concentration-time curve (8.0 +/- 2.4 to 18.2 +/- 3.1 ng ml-1 h; P < 0.001; mean +/- s.d.). Peak triazolam concentration was increased (2.1 +/- 0.7 to 3.6 +/- 1.0 ng ml-1, P < 0.05) and the elimination half-life prolonged (4.1 +/- 2.1 to 7.6 +/- 1.9 h; P < 0.01). The PSV, EEG, and VAS of the triazolam plus diltiazem group revealed significant differences from the triazolam alone group or the control placebo group.

CONCLUSIONS

Diltiazem markedly affects the pharmacokinetics of triazolam and increases the intensity of its sedative effects. Inhibition of CYP3A isozyme by diltiazem may explain the observed pharmacokinetic interaction. Therefore, triazolam should be avoided when patients are using diltiazem.

Cardiac and hemodynamic effects of TZC-5665, a novel pyridazinone derivative, and its metabolite in humans and dogs

1. TZC-5665 is a novel pyridazinone derivative with vasodilatory and beta-adrenergic blocking activities and type III phosphodiesterase inhibitory action. 2. In healthy volunteers, TZC-5665 was rapidly absorbed and immediately metabolized. Its main metabolite, M-2, remained at a higher concentration in plasma. Orally administered TZC-5665 reduced end-diastolic left ventricular volume (20.16 ml) and exhibited a tendency to increase ejection fraction (0.04). 3. In dogs, M-2 dose-dependently increased cardiac contractility and reduced both preload and afterload. These effects appeared more potent in the failed heart than in the normal heart. At the same dose (30 micrograms/kg), the effects of M-2 seem to be more potent than those of milrinone. 4. We concluded that TZC-5665 is a useful medication for treating patients with chronic congestive heart failure (CHF) because of the positive inotropic and vasodilating effects due to its active metabolite in addition to its own beta-adrenergic blocking actions.

Evaluation of the disintegrin, triflavin, in a rat middle cerebral artery thrombosis model

Platelet aggregation plays a important role in the thrombotic cerebral infarction. The final common mechanism in the formation of a platelet aggregate is the linking of adjacent platelets by fibrinogen binding to the platelet integrin alpha 11b beta 3. In this study, we evaluated the effect of the disintegrin, triflavin, in a rat middle cerebral artery thrombosis model. Thrombus at the left middle cerebral artery in rat was induced by photochemical reaction between rose bengal and green light, which caused endothelial injury at the site of irradiation. We measured the time to occlusive thrombus formation and the size of ischaemic cerebral damage. Triflavin dose dependently prolonged the time to occlusive thrombus formation in this model. Triflavin also reduced the size of ischaemic cerebral damage on examination at 24 h after photochemical reaction. Triflavin dose dependently inhibited ADP- and collagen-induced platelet aggregation and platelet retention in the collagen-coated beads method ex vivo. These effects were thought to result from the blockade of platelet integrin alpha IIb beta 3. Blockade of platelet integrin alpha IIb beta 3 may be useful in the prevention of cerebral arterial thrombosis.

Effect of prostaglandin E1 on the rat inner ear microvascular thrombosis

1. The effect of prostaglandin E1 was investigated with a two-rat model of hearing disturbance and equilibrium dysfunction associated with inner ear microvascular thrombosis. 2. The inner ear microvascular thrombosis was induced by photochemical reaction between Rose Bengal and transmural green light (540 nm). Photochemical reaction causes endothelial injury followed by platelet adhesion, aggregation, and formation of a platelet- and fibrin-rich thrombus. 3. Under anesthesia, the cochlea or the vestibule was irradiated with green light to induce hearing disturbance or equilibrium dysfunction. 4. In the hearing disturbance model, a compound cochlear nerve action potential was recorded by electrocochleography every minute after the beginning of photoirradiation in the presence of Rose Bengal. 5. In the equilibrium dysfunction model, the photoirradiation was applied for 10 min after Rose Bengal administration. The behavior of rats was observed in the swimming test, and nystagmus was observed 24 hr after the end of photoirradiation. 6. Prostaglandin E1 significantly (P < 0.05) prolonged the time required to suppress the action potential. In the swimming test, 3 of the 6 animals treated with prostaglandin E1 did not rotate about their longitudinal axes (equilibrium dysfunction) and the duration of well-balanced swimming was significantly prolonged (P < .001). Prostaglandin E1 significantly (P < 0.05) suppressed the appearance of nystagmus. 7. In conclusion, prostaglandin E1 potentially prevents hearing disturbance and equilibrium dysfunction due to inner ear microvascular disorders.

Electrophysiologic effects of nitrous oxide, a volatile anesthetic, in dogs following myocardial infarction in comparison with other anesthetics

The present study was undertaken to examine the electrophysiologic effects of nitrous oxide in the dog heart after inducing myocardial infarction, and to compare these with those of other anesthetics. Myocardial infarction was produced by two-stage ligation of the left anterior descending coronary artery in dogs. Seven days after ligation, bipolar electrodes were sutured on the ventricular surface of the infarcted and normal regions for applying electrical stimulation or recording ventricular activation. Ventricular activation time and QT interval on the bipolar electrocardiogram and PQ interval from the standard limb lead II were measured during atrial pacing. Nitrous oxide 80% did not significantly prolong ventricular activation time, PQ interval or QT interval. However, halothane 1 minimum alveolar concentration (MAC), thiopental 5 and 10 mg/kg and fentanyl 30 microg/kg did prolong ventricular activation time; thiopental and fentanyl prolonged the QT interval. Nitrous oxide did not potentiate the effects of fentanyl. Therefore, electrophysiologic effects of nitrous oxide are much weaker compared with those of thiopental, fentanyl or halothane.

Thromboxane A2 synthetase inhibition suppresses cough induced by angiotensin converting enzyme inhibitors

Based on our earlier animal study, we became interested to investigate if thromboxane A2 (TXA2) is involved in angiotensin converting enzyme (ACE) induced cough in man. To 11 patients with hypertension, who had developed cough induced by ACE inhibitors, a TXA2 synthetase inhibitor, ozagrel was given for 1 to 2 months together with the ACE inhibitors. One patient developed headache induced by ozagrel and was eliminated from the study after 3 weeks. In other 10 patients, no obvious drug attributable abnormality was observed in subjective and objective symptoms or laboratory tests. In ten patients, cough scores were taken just before and after the administration of a combination of an ACE inhibitor with ozagrel. Median values of cough scores after the combination was significantly (p=0.012) lower than before the combination. Ozagrel reduced cough scores in 5 patients, completely suppressed cough in 3 patients and in 2 of 10 patients, ozagrel did not affect cough scores. Our observations suggest that TXA2 may somehow, mediate coughing induced by the ACE inhibitors. Further, patients on ACE inhibitors who develop cough may benefit from TXA2 synthetase inhibitors.

A flow cytometric analysis of the expression of adhesion molecules on human renal cell carcinoma cells with different metastatic potentials

OBJECTIVES

We investigated the relationship between the metastatic potential and the surface expression of adhesion molecules on human renal cell carcinoma (HRCC) cells.

METHODS

The metastatic potential was studied by the intravenous injection of cells from an HRCC cell line SN12C parent and its variants, SN12C-MM3, SN12C-clone2 and SN12C-clone8 into athymic Balb/c nude mice. The surface expression of adhesion molecules on these four HRCC cell lines was studied by a flow cytometric analysis.

RESULTS

Of the four cell lines, SN12C-MM3 had the highest ability to produce pulmonary metastatic nodules. In contrast, the SN12C parent, SN12C-clone2 and SN12C-clone8 produced either few or no pulmonary metastatic nodules. A flow cytometric analysis revealed that SN12C-MM3 showed a strong expression of sialyl Lewis X (sialyl Le(x)) carbohydrate antigen and a slightly stronger expression of CD11a (LFA-1 alpha-chain) and CD54 (ICAM-1) compared with the other three cell lines. All cell lines expressed CD29 (beta 1-integrin) and CD44 to the same extent.

CONCLUSION

Sialyl Le(x) is thought to be a ligand for the adhesion molecule called ELAM-1 (endothelial-leukocyte adhesion molecule-1, E-selectin) and mediates the interaction of leukocytes or tumor cells to endothelial cells, followed by the integrin-mediated adhesion. These data suggest that SN12C-MM3 cells may have more of a chance to adhere to endothelial cells in blood vessels and consequently shows a higher metastatic potential when injected intravenously in comparison to the other three lines.

Expression of the Ets-1 proto-oncogene in human gastric carcinoma: correlation with tumor invasion

The proto-oncogene Ets-1 is a transcription factor known to control the expression of a number of genes involved in extracellular matrix remodeling and has been postulated to play a role in cell migration and tumor invasion. To elucidate the involvement of Ets-1 in human gastric carcinomas, we examined 11 cases of gastric adenoma and 110 cases of gastric carcinoma by immunohistochemistry and compared the degree of Ets-1 expression with the depth of carcinoma invasion. Ets-1 was not expressed either in the normal gastric epithelium or in gastric adenomas. Among the 110 cases with gastric adenocarcinoma, 70 (63.6%) showed positive staining for the Ets-1 protein. In mucosal carcinomas, only 3 of 26 cases (11.5%) showed positive immunostaining for Ets-1. In contrast, 67 of 84 cases (79.8%) with submucosal or more invasive carcinomas showed immunopositivity and intense staining for Ets-1 in the tumor cells. The pattern of Ets-1 immunostaining in mucosal carcinomas was weak and differed from that of other local invasive carcinomas (P < 0.001). Histologically, signet-ring cell and mucinous carcinomas expressed relatively weak positivity for Ets-1. Ets-1 expression correlated significantly with the presence of lymph node metastasis (P < 0.001). In situ hybridization, using an Ets-1 oligonucleotide probe, also confirmed the presence of Ets-1 mRNA in gastric carcinomas. Expression of Ets-1 mRNA was also detected in four different kinds of cultured human gastric carcinoma cell lines by the reverse transcription polymerase chain reaction method. These findings suggest that Ets-1 is overexpressed in gastric mucosal cells that have undergone malignant conversion and that Ets-1 is one of the factors involved in the penetration of gastric carcinoma beyond the muscularis mucosa.

Effect of dexamethasone on invasion of human squamous cell carcinoma cells into collagen gel

The effect of dexamethasone (Dex) on the ability to invade type I collagen gel was investigated in two cell lines of oral squamous cell carcinoma (SCC). At concentrations higher than 10(-8) M, Dex significantly suppressed the invasive growth of SCC cells into the gel. The same concentrations of Dex led to a decrease in urokinase type plasminogen activator (u-PA) synthesis and an increase in plasminogen activator inhibitor type 1 (PAI-1) synthesis by SCC cells. These findings suggest that Dex inhibits the invasiveness of SCC cells by decreasing their proteolytic activity.

Evaluation of in-vivo transdermal absorption of cyclosporin with absorption enhancer using intradermal microdialysis in rats

The purpose of this study was to evaluate the effect of absorption enhancer on in-vivo transdermal absorption of cyclosporin using intradermal microdialysis in rats. Cyclosporin oily solutions (0.5, 2, 8% w/v) were prepared from Sandimmun (10% w/v oily oral preparation of cyclosporin) by diluting with olive oil. 1-[2-(Decylthio)ethyl] azacyclopentan-2-one (HPE-101) and glycerin were added to the cyclosporin formulation as an absorption enhancer at various concentrations between 1 and 20%. These formulations were applied to the shaved abdomen of rats treated with intradermal microdialysis at a flow rate of 2.5 microL min-1 for 6 h. Cyclosporin was immediately detected and attained a plateau in the dermal dialysate after topical application of cyclosporin oily solution alone. Cyclosporin levels in the dialysate increased with increasing cyclosporin concentrations in the formulation from 0.5 to 8% (w/v). HPE-101 did not influence cyclosporin absorption at concentrations less than 6% (w/v). Addition of 10% (w/v) HPE-101 significantly enhanced an apparent absorption rate of cyclosporin by 4.9 times. However, 20% (w/v) HPE-101 did not show the enhancing activity. On the other hand, addition of glycerin at concentrations of 6, 10, and 20% (v/v) significantly enhanced an apparent absorption rate of cyclosporin by 3.0, 6.4, and 6.9 times, respectively. The time lag for cyclosporin absorption was less than 0.21 h in all tested cases. This microdialysis study shows that glycerin is a suitable enhancer for improving the in-vivo cyclosporin absorption from the skin.