[The inhibitory effect of oxaprozin, a new non-steroidal anti-inflammatory drug, on platelet aggregation]

The inhibitory effects of oxaprozin, a new non-steroidal anti-inflammatory drug, on platelet aggregation and prostaglandin (PG) synthetase activity were studied. In arachidonic acid (AA)-induced rabbit platelet aggregation in vitro, oxaprozin exhibited a dose-dependent inhibitory effect, and its median inhibitory concentration was 124.2 microM. The effect of oxaprozin was less potent than that of indomethacin and piroxicam, equipotent as that of aspirin and phenylbutazone, and 2 times as potent as that of ibuprofen. In collagen-induced rat platelet aggregation ex vivo, oxaprozin showed a weak but significant inhibitory effect with oral dose of 300 mg/kg. Indomethacin, aspirin and ibuprofen exhibited an inhibitory effect with 100 mg/kg. Although phenylbutazone also exhibited an inhibitory effect with 300 mg/kg, the effect was more potent than that of oxaprozin. ADP-induced platelet aggregation both in rabbit in vitro and rat ex vivo was not affected by oxaprozin. Moreover, oxaprozin administered orally inhibited dose-dependently AA-induced pulmonary thrombotic mortality in mice, and its median effective dose was 56.4 mg/kg. The effect of oxaprozin was less potent than of sulindac, piroxicam and ibuprofen, equipotent as that of aspirin, and 5 times as potent as that of phenylbutazone. On the other hand, oxaprozin inhibited dose-dependently PG synthetase activity. The inhibitory effect of oxaprozin was less potent than that of indomethacin and piroxicam, almost equipotent as that of ibuprofen, and more potent than that of phenylbutazone and aspirin. These results suggest that oxaprozin, like many other acidic non-steroidal anti-inflammatory drugs, suppresses platelet aggregation by mainly inhibiting PG synthetase activity.

[Anti-inflammatory activity of a non-steroidal anti-inflammatory agent, oxaprozin, in experimental models]

Anti-inflammatory activity and mode of action of oxaprozin, a new non-steroidal anti-inflammatory agent, were investigated in experimental animal models and in vitro tests. Anti-inflammatory potency of oxaprozin was almost equal to that of aspirin in acetic acid vascular permeability, carrageenin hind paw edema, cotton pellet granuloma and adjuvant arthritis tests in rats. On the other hand, in mice, oxaprozin was more potent than aspirin, ibuprofen and phenylbutazone, and it was as potent as sulindac and fenbufen in acetic acid vascular permeability and carrageenin hind paw edema tests. In adrenalectomized rats, the anti-edema activity of oxaprozin in the carrageenin hind paw edema test was the same as that in intact rats. Oxaprozin inhibited erythema formation induced by ultra-violet rays in guinea pigs. The inhibitory potency of oxaprozin against prostaglandin E2 biosynthesis in vitro was equal to that of ibuprofen. Oxaprozin showed a concentration-dependent inhibition of heat-induced denaturation of bovine serum albumin and lysis of rabbit erythrocytes in vitro. However, oxaprozin did not inhibit rat hind paw edemas induced by dextran, formalin and serotonin. It was suggested from these results that the mode of action of oxaprozin is similar to those of other acidic non-steroidal anti-inflammatory drugs. Ulcerogenicity of oxaprozin was weaker than those of phenylbutazone and aspirin in rats. Species differences in the metabolic rate of oxaprozin were shown. The blood concentration of oxaprozin in rats is extremely low because the metabolic rate of oxaprozin is rapid in rats. Therefore, in rats, oxaprozin exhibited a weak anti-inflammatory effect. However, in mice, oxaprozin had a low metabolic rate, and the effect of oxaprozin was as potent as sulindac and fenbufen. The elimination half-life of oxaprozin is extended, 49 to 69 hr, in humans. It was suggested from these findings that oxaprozin is a potent and long acting anti-inflammatory drug in clinical use.

Time-dependent inhibition of prostaglandins synthesis by nonsteroidal antiinflammatory drugs; time-dependent alteration of inhibitory effect and characteristics of its active site

The characteristics of the time-dependency of nonsteroidal antiinflammatory drugs (NSAIDs) and their active sites in inhibiting cyclooxygenase activity were investigated using bovine seminal vesicle microsomal fraction. The Hill's coefficients of the inhibition curve of most NSAIDs were approximately 1.0, except for some drugs which had Hill's coefficients that were obviously more than 1.0. The values for indomethacin, diclofenac and flurbiprofen were approximately 1.5, 1.7 and 2.0, respectively. A time-dependent cyclooxygenase inhibiting effect was observed only with the NSAIDs in the group which had Hill's coefficients that were significantly more than 1.0. A time-dependent increase in inhibiting activity of these drugs was observed by the change in the inhibition curve. Time-dependently, the Hill's coefficient of the curve of the NSAIDs approached 1.0 from more than 1.0. With this change, the shift of the curve to the left was also observed time-dependently. These changes in the curve were no longer seen when the Hill's coefficient dropped to 1.0. These time-dependent effects were protected by salicylic acid, which did not have any effect on cyclooxygenase activity in vitro, in a dose-dependent manner. These results suggested that the two classes of NSAIDs, time-dependent and non-time-dependent, are clearly differentiated by the slope of the inhibition curve of NSAIDs. Furthermore, the present results indicate that the degree of time-dependence of the NSAIDs depends on the Hill's coefficient of the inhibition curve, and the value is important for the potency of the cyclooxygenase inhibition, in addition to the affinity for the catalytic site of the enzyme.

The difference in the site of actions of tricyclic antidepressants and methamphetamine on the duration of the immobility in the behavioral despair test

A single administration of tricyclic antidepressants reduced the duration of the immobility in the behavioral despair test. The escape-directed behavior of tricyclic antidepressant-treated rats was observed in a cylinder partially filled with water. In contrast, although methamphetamine also reduced the duration of the immobility, an increase in the general motor activity was shown in methamphetamine-treated rats. Tricyclic antidepressants injected into the medial amygdaloid nucleus, not into the nucleus accumbens, suppressed the duration of the immobility. Methamphetamine completely suppressed the duration of the immobility not only when injected into the medial amygdaloid nucleus, but also when injected into the nucleus accumbens. The present results suggest that in the rat behavioral despair test, the medial amygdaloid nucleus may play an important role in the selective reductive effect on the duration of the immobility.

[The analgesic and antipyretic effects of a non-steroidal anti-inflammatory drug, oxaprozin, in experimental animals]

The analgesic and antipyretic effects of oxaprozin were investigated in comparison with those of indomethacin, ibuprofen, phenylbutazone and aspirin. On the various writhing tests in mice, the analgesic effect of oxaprozin was about 2 to 9 times more potent than those of ibuprofen, phenylbutazone and aspirin. On the other hand, the analgesic and antipyretic effects of oxaprozin in rats were roughly equivalent to those of aspirin, but less effective than those of the other drugs tested. On the urate synovitis test in dogs, only oxaprozin showed a prophylactic effect. Therefore, The effect of oxaprozin in mice and dogs was more potent than ibuprofen, phenylbutazone and aspirin. The metabolic rate of oxaprozin in rats is 3.5 and 7.2 times more rapid than in mice and dogs, respectively, and its blood level in rats is low. Moreover, the biological half-life of oxaprozin is 39 to 43 hr and 49 to 69 hr in dogs and humans, respectively. From these results, it is suggested that oxaprozin is more potent than ibuprofen, phenylbutazone and aspirin, and in clinical use, it is a long acting anti-inflammatory drug.

Inhibition of electrically-induced vocalization in adjuvant arthritic rats as a novel method for evaluating analgesic drugs

A new method for the evaluation of analgesic drugs in normal rats and in rats with hyperalgesia induced by adjuvant was developed using the vocalization response as an indicator of pain due to electrical shock. It was demonstrated that at ED50 doses, nonsteroidal anti-inflammatory drugs (NSAIDs), narcotic analgesic drugs and narcotic agonist/antagonist type analgesic drugs were effective, but pure narcotic antagonist drugs. CNS-acting drugs and anti-inflammatory steroid were ineffective. Acidic NSAIDs, except aspirin, were more effective in adjuvant arthritic rats than normals but other analgesic drugs had roughly the same effect in both. It was suggested that the acidic NSAIDs specifically inhibit inflammatory pain. Moreover, the vocalization response under adjuvant treatment is useful for the quantitative measurement of analgesics.

Effects of reserpine, alpha-methyl-p-tyrosine, p-chlorophenylalanine and 5,7-dihydroxytryptamine on the hippocampal kindling effect in rats

The role of the brain monoamines in the development of hippocampal kindling was studied. Reserpine markedly facilitated the formation of hippocampal kindling. The high amplitude spike waves in the amygdala and reticular formation appeared earlier in the reserpine treated rats than in the saline injected rats. alpha-Methyl-p-tyrosine did not have any effect on the formation of hippocampal kindling. Systemic injection of p-chlorophenylalanine and intraventricular injection of 5,7-dihydroxytryptamine also did not have any effect on the formation of hippocampal kindling. Progressive changes of afterdischarge elicited by hippocampal stimulation in the alpha-methyl-p-tyrosine, p-chlorophenylalanine and 5,7-dihydroxytryptamine treated rats are the same as those in the saline injected rats. These results indicate that the decrease in both catecholamines and serotonin levels caused a marked facilitation of the hippocampal kindling formation, but the separate decrease in either catecholamines or serotonin did not produce a significant effect.

Effect of taurine on depolarizations induced by L-glutamate and other excitatory amino acids in the isolated spinal cord of the frog

The effect of taurine on depolarizing responses to L-glutamate (L-glu) was examined in isolated frog spinal cord using the sucrose gap method. Taurine (1 mM) reduced L-glu-induced depolarization in ventral and dorsal roots, even when calcium ion was deleted from or EGTA was added to the perfusate. GABA (1 mM) showed little or no effect on the L-glu response. A log dose-depolarization curve for L-glu was found to be shifted by taurine (1 mM) to the right in a non-parallel fashion. Strychnine blocked the taurine effect completely, while picrotoxin produced a partial reduction, and bicuculline exhibited no blockade at all. The depolarizations by 3-types of excitatory amino acids were also inhibited by taurine in the following order: N-methyl-D,L-aspartate greater than kainate greater than quisqualate. These results suggest a possibility that taurine but not GABA inhibits the depolarization mediated by excitatory amino acid receptors, and this may explain, in part, the inhibitory action of taurine in the central nervous system.

Characteristics of glucocorticoid-binding sites of rat liver: different effects of adrenalectomy on the binding

Hydrocortisone (HC) in rat liver cytoplasmic fraction was bound to three different binding sites with high, medium and low affinity. Dissociation constants (Kd) were approx. 2.1, 22 and 208 nM; and the densities of these binding sites were about 40, 50 and 10% of total number of binding sites, respectively. The binding site for dexamethasone (DM) of the cytoplasmic fraction was the medium affinity one among these three components. The maximum number of binding sites (Bmax) of HC and DM was significantly increased by adrenalectomy. The Bmax of HC was about twice as great as that of DM in normal and adrenalectomized rat liver. DM inhibited 3H-HC binding in a dose-dependent manner but inhibition did not exceed 50% in either normal or adrenalectomized rats. Following adrenalectomy, the Bmax of the medium affinity-site for HC was significantly increased, while the high affinity component disappeared. By adding DM to the cytoplasmic fraction of adrenalectomized rat liver in vitro and in vivo, the Bmax of the medium affinity-site was significantly decreased, and a high affinity component of HC was revealed with a significant increase in the number of binding sites. These results indicate that the binding site for DM is one component of the HC binding site; and following adrenalectomy, the number of each type of binding site for glucocorticoids increases differently from the others.

Immunopharmacologic studies of D-penicillamine-L-cysteine disulfide

Effects of D-penicillamine-L-cysteine disulfide (P-C) on some immunological parameters were examined in normal and immunity-impaired mice and rats. P-C enhanced the DNA synthesis in concanavalin A-stimulated mouse spleen cell cultures in vitro. In vivo, administration of P-C produced either enhancement or depression of plaque forming cell (PFC) response and delayed type hypersensitivity (DTH) to sheep red blood cells (SRBC) in low responder mice to SRBC, depending on the dose of P-C. P-C restored the impaired PFC response in hydrocortisone-pretreated mice. The enhancing effect of P-C was not shown in high responder mice to SRBC, but an inhibiting effect was observed. P-C inhibited the suppressor cell induction on PFC response in mice immunized with a supraoptimum dose of antigen. In adjuvant arthritic rats, P-C induced severe arthritis by eliminating the suppressor cells regulating this disease process. The relevance of these findings and mode of action of D-penicillamine in rheumatoid arthritis is discussed.

Polyamine inhibition of gastric ulceration and secretion in rats

The effect of polyamines on gastric ulceration and secretion in rats was studied. Stress-induced gastric ulceration and ulceration in pylorus-ligated rats were inhibited by subcutaneous or oral administration of spermine; spermidine's inhibitory effect was somewhat less. Histamine-induced ulceration was also inhibited by the subcutaneous injection of spermine. In addition, the daily oral administration of spermine for 10 days was therapeutic against an acetic acid-induced ulcer (chronic ulcer). Gastric secretion in pylorus-ligated rats and in rats with fistulae and stimulated by histamine injection was decreased by the subcutaneous injection of spermine.

The role of noradrenergic and serotonergic systems in the hippocampal kindling effect

The role of the noradrenergic and the serotonergic systems in the development of hippocampal and amygdaloid kindling was studied. Dorsal noradrenaline bundle lesions markedly facilitated the formation of hippocampal and amygdaloid kindling. The most significant facilitation was observed in the earliest phase of kindling. Cortical noradrenaline content decreased by about 70% after dorsal noradrenaline bundle lesions. Midbrain raphe nuclei (both dorsal and medial raphe nuclei) lesions did not have any effect on the formation of both hippocampal and amygdaloid kindling. These results indicate that the dorsal noradrenaline bundle system plays an inhibitory role in the development of the seizure discharges and the behavioral convulsions in hippocampal and amygdaloid kindling.

Effect of 2'-carboxymethoxy-4,4'-bis(3-methyl-2-butenyloxy)chalcone (SU-88) on gastric local blood flow

Effect of 2'-carboxymethoxy-4,4'-bis(3-methyl-2-butenyloxy)chalcone (SU-88), a new anti-ulcer drug, on gastric tissue blood flow was investigated by using an inhaled hydrogen gas clearance method in rats. As a result, following the intravenous infusions of 10,20 and 30 mg/kg/h of SU-88, the gastric blood flow increased with an increase rate of 38.1, 70.5 and 61.7% as compared with the control value, respectively. Following the intraperitoneal administrations of 50 and 100 mg/kg of SU-88, the gastric blood flow increased by 59.8 and 51.2%, respectively, immediately after the administration.

[Middle cerebral artery occlusion with Moyamoya phenomenon.--2nd report: report of an autopsy case]

About the middle cerebral artery occlusion with moyamoya phenomenon, we have reported the clinical and angiographical study of 10 cases. Now we present an autopsy case. A 53-year-old female was admitted to our hospital on May, 22, 1978, two hours after an apparent subarachnoid hemorrhage. Neurological examination revealed drowsiness, nuchal rigidity right hemiparesis and motor aphasia. Left carotid angiogram showed an occlusion of the left middle cerebral artery at its origin with moyamoya phenomenon, but did not demonstrate an occlusion and/or stenosis of the intracranial internal carotid artery. Furthermore right carotid and bilateral vertebral angiograms were normal. The hospital course was progressively uphill, and she did not have any focal neurological deficits at discharge. But she committed suicide with a poison (Paraquat) on August, 19, 1978. Histopathologic examination of the left middle cerebral artery revealed a stenosis, with a maximum diameter of 900 microns. In this portion the lumen was not be occluded, and arteriosclerotic and inframatric exchanges were not present. The elastica interna was reduplicated, frayed and at times discontinuous. The tunica media was very thin or disappeared. On the other hand, moyamoya vessels were found between distal and peripheral portion of the stenotic middle cerebral artery as a collateral circulation. These findings suggested that the stenotic arterial wall of the left middle cerebral artery might be a congenital hypoplasia.

[Effects of the anti-ulcer drug SU-88 on the gastric blood flow and the cardiovascular system (author's transl)]

Effects of a newly synthetized anti-ulcer drug, 2'Carboxymethoxy-4,4'-bis(3-methyl-2-butenloxy)chalcone (SU-88), on gastric blood flow and the cardiovascular system were investigated. Intravenously administered SU-88 dose-dependently increased the blood flow of gastric tissues in rats. In anethetized dogs, i.a. administered SU-88 also increased the short gastric and the femoral arterial blood flows. SU-88 (i mg/kg, 3 mg/kg and 10 mg/kg i.v.) caused a mild fall in systemic blood pressure, an increase in heart rate, and a stimulation of respiration; however, these effects were only transient and recovered to the basal level within few minutes. No notable changes were observed in the electrocardiogram except for a shortening of the R-R interval accompanied by an increase in heart rate. The blood flow of the common carotid, the vertebral, the coeliac, the superipor mesenteric, and the femoral arteries in dogs were all increased by i.v. administration of SU-88, and among them an increase in the coeliac arterial blood flow was prominent. SU-88 increased the perfusates in isolated rabbit ear and relaxed the contraction of isolated rabbit aorta induced by noradrenaline, but showed no influences on the amplitude, heart rate, and coronary flow of isolated rabbit heart. The hypotensive effect of SU-88 was not abolished by i.v. administered atropine, diphendydramine, and propranolol and not influenced by vagotomy. Intraverterbrally administered SU-88increased the vertebral blood flow, but showed no influence on systemic blood pressure. Furthermore, SU-88 showed no influence on the rise in blood pressure by both common carotid occlusions. The increase in the femoral and the short gastric arterial blood flow induced by i.a. administration of SU-88 was not inhibited by atropine, diphenhydramine, and propranolol and not influenced by pretreatment with aminophylline. These results suggest that the hypotensive and vasodilative effects of SU-88 are not mediated by the central nervous system, autonomic nervous system, histamine and the action of adenosine augmentation and further experiments are necessary for precise explanations of its mechanism.

Hippocampal kindling and effects of antiepileptic drugs

The kindling effect of the hippocampus was investigated in rats. The development of behavioral manifestations in hippocampal kindling was similar to that seen in the case of amygdaloid kindling, but many more stimulations were required to evoke behavioral convulsions in the former. The transfer phenomenon from amygdala to hippocampus was evident. There were no differences in effects of drugs on the seizure-discharge and the behavioral convulsions between the amygdaloid and the hippocampal kindled rats. The present results suggest that the amygdala plays an important role in the formation of hippocampal kindling, especially in the manifestation of behavioral changes. The hippocampal kindled rat, as well as amygdaloid kindled rat, is useful animal model for evaluating the antiepileptic effect of various drugs.

[Spontaneous thrombosis of an azygos anterior cerebral artery aneurysm--report of a case (author's transl)]

A case of spontaneous thrombosis of azygos anterior cerebral artery aneurysm was reported. A 39-year-old man was admitted to our hospital on April 23, 1979, 5 days following an apparent attack of subarachnoid hemorrhage. On admission, he complained a headache and left hemiparesthesia. Neurologic examination revealed a very slight nuchal rigidity, left hemihypesthesia and hypalgesia. Routine laboratory studies were noncontributory. Left and right carotid angiograms showed an azygos anterior cerebral artery aneurysm. Twelve days after the attack, a left carotid angiogram demonstrated a segmental narrowing and widening of an azygos anterior cerebral artery, and then the aneurysm was filled incompletely. Nineteen days after the attack, the aneurysm was not visualized on right carotid angiogram. Neck clipping and resection of the aneurysm was performed on May 8, 1979. Cross section of the aneurysm exposed a thrombus. He showed postoperatively a slight hypesthesia in the left lower limb. Complete thrombosis of intracranial aneurysm occurring spontaneously is rare. We collected 42 such cases including the present case from the literature and discussed some factors facilitating intraluminal thrombosis. Although the shortest previous period of thrombosis is noted to be over a course of 5 days, the thrombosis in our case in 19 days after subarachnoid hemorrhage was certainly a relative rapid event.

The action of chlorphenesin carbamate on the frog spinal cord

Studies were carried out to elucidate the mechanism of action of chlorphenesin carbamate (CPC) and to compare the effect of the drug with that of mephenesin on the isolated bullfrog spinal cord. Ventral and dorsal root potentials were recorded by means of the sucrose-gap method. CPC caused marked hyperpolarizations and depressed spontaneous activities in both of the primary afferent terminals (PAT) and motoneurons (MN). These hyperpolarizations were observed even in high-Mg2+ and Ca2+-free Ringer's solution, suggesting that CPC has direct actions on PAT and MN. Various reflex potentials (dorsal and ventral root potentials elicited by stimulating dorsal and ventral root, respectively) tended to be depressed by CPC as well as by mephenesin. Excitatory amino acids (L-aspartic acid and L-glutamic acid) caused marked depolarizations in PAT and MN, and increased the firing rate in MN. CPC did not modify the depolarization but abolished the motoneuron firing induced by these amino acids. However, mephenesin reduced both the depolarization and the motoneuron firing. The dorsal and ventral root potentials evoked by tetanic stimulation (40 Hz) of the dorsal root were depressed by the drugs. These results indicate that CPC has an apparent depressing action on the spinal neuron, and this action may be ascribed to the slight hyperpolarization and/or the prolongation of refractory period.

Traumatic cerebral aneurysm associated with widening skull fracture. Report of two infancy cases

Two cases of traumatic cerebral aneurysm associated with widening skull fracture are reported. Cases of traumatic aneurysms in infants are particularly rare, and there have been no reported cases associated with widening skull fracture.

[Studies on the physical dependence liability of chlorphenesin carbamate (author's transl)]

Physical dependence liability of chlorphenesin carbamate (CPC) was studied in parallel with phenobarbital-Na (PB). Beagle dogs were used and the overall duration of the experiment was 85 days, i.e. the first dosing period was 42 dyas (6 weeks) in which drugs were repeatedly administered orally once daily, followed by a withdrawal period (7 days), the second dosing period was continued from the 50th-78th day in which the form and schedule of drug administration was as in the first dosing period. The last 79th to 85th days were used for substitution experiments. In both dosing periods, PB but not CPC showed signs of tolerance formation. Severe withdrawal syndrome was observed in PB administered dogs whereas there were no changes of behavior observed in CPC-dogs by withdrawal and substitution procedures, respectively. CPC apparently does not have a physical dependence liability.