Biomedical subjects

M Akima

Publications and source records attributed to M Akima.

At least 37 records · Page 2Linked to original sources

PubMed1997

Malignant glomus tumor: a case report and review of the literature.

This report concerns a malignant glomus tumor, a rare soft tissue tumor that was examined immunohistochemically and ultrastructurally. It occurred in a 44-year-old male patient who had suffered from dull pain and stiffness in the right thigh for 10 months. Radiographic examination revealed a well-defined osteolytic lesion in the diaphysis of the right femur. Hypervascularity of the tumor was observed angiographically. Computed tomographic and magnetic resonance examinations showed an intramuscular mass invading the marrow space of the femur. Wide resection was performed after open biopsy. Histologically, round to polygonal tumor cells revealed a uniform appearance of round to ovoid nuclei with single large nucleoli and slightly eosinophilic cytoplasm, forming solid sheets of cells interrupted by vessels of varying size. A few mitotic figures and vascular invasion were observed. Immunohistochemically, vimentin and alpha-smooth muscle actin were stained intensely, and muscle actin was positive for tumor cells of the perivascular area. Tumor cells were negative for desmin, factor VIII-related antigen, S-100 protein, neurofilament, cytokeratin, and epithelial membrane antigen. Ultrastructurally, tumor cells were characterized by many cytoplasmic processes, pinocytotic vesicles, plasmalemmal dense plaques, and scattered microfilaments in the cytoplasm. Few cell junctions and focal basement membrane-like structures were observed. No recurrence or metastasis was noted 57 months after operation. This case was considered to be a malignant glomus tumor, that is, a glomangiosarcoma arising de novo.

Actins↗

PubMed1996

Actions of CP-060S on veratridine-induced Ca2+ overload in cardiomyocytes and mechanical activities in vascular strips.

CP-060S, (-)-(S)-2-[3,5-bis(1, 1-dimethylethyl)-4-hydroxyphenyl]-3-[3-[N-methyl-N-[2-(3, 4-methylenedioxyphenoxy)ethyl]amino]propyl]-1,3-thiazolidin- 4-one hydrogen fumarate, is a novel cardioprotective drug which is designed to prevent Ca2+ overload and cause vasorelaxation. The effects of this compound were evaluated and compared with those of CP-060R (enantiomer of CP-060S,) and diltiazem (Ca2+ channel antagonist) in a veratridine-induced model of Ca2+ overload and vasorelaxation. After 5-min superfusion of veratridine (74 microM), intracellular free calcium concentrations ([Ca2+]i) of rat single cardiomyocytes, as measured with the fura-2 procedure, were greatly elevated, from 44 +/- 5 nM to 3705 +/- 942 nM, and subsequently generated cell contracture. Pretreatment of cardiomyocytes with more than 300 nM of CP-060S or CP-060R for 30 min provided almost complete protection against the veratridine-induced cell contracture; in CP-060S(1 microM)-treated myocytes, [Ca2+]i were minimal and partially elevated from 42 +/- 5 nM to 72 +/- 14 nM after 5 min of veratridine superfusion. In comparison, diltiazem showed no protection below 1 microM and only partial protection at 10 microM. CP-060S, CP-060R and diltiazem all shifted the concentration-response curve for CaCl2 to the right in a competitive manner in depolarized rat thoracic aorta. The pA2 values of CP-060S, CP-060R and diltiazem were 9.16 +/- 0.18, 8.24 +/- 0.14 and 7.66 +/- 0.09, respectively. Our results indicate that CP-060 behaves stereoselectively as a Ca2+ channel antagonist and non-stereo-selectively to protect against veratridine-induced contracture. The latter effect suggests that Ca2+ entry blockade is not the mechanism by which CP-060S exerts cardioprotection.

Animals↗

PubMed1995

Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. V. Thienopyridazinone derivatives.

Synthesis and pharmacological evaluation of novel thienopyridazinones and related compounds are described. A thiophene ring was found to be able to replace the benzene ring of a phthalazinone without loss of biological activities. This observation supports our hypothesis that the benzene ring plays an important role in both thromboxane A2 (TXA2) synthetase-inhibitory and bronchodilatory activities. Further, it was shown that the carbonyl moiety of a phthalazinone is not necessary for these activities.

Administration, Oral↗

PubMed1995

Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. VI. Indazole derivatives.

Synthesis and pharmacological evaluation of novel indazole derivatives are described. These compounds were found to exhibit both thromboxane A2 (TXA2) synthetase-inhibitory and bronchodilatory activities. This observation supports the idea that the partial structure of the 3-pyridyl and phenyl groups with a methylene insertion is an important component for well-balanced activities.

Administration, Oral↗

PubMed1995

GM-109: a novel, selective motilin receptor antagonist in the smooth muscle of the rabbit small intestine.

The pharmacological properties of the cyclic peptide Phe-cyclo[Lys-Tyr(3-tBu)-beta Ala-].trifluoroacetate (GM-109), a selective motilin antagonist, were investigated in the smooth muscle of the rabbit small intestine. GM-109 (0.1-3 microM) competitively inhibited contractions induced by porcine motilin (pMTL) in rabbit isolated duodenum longitudinal strips, with a pA2 value of 7.37 +/- 0.24. However, the contractile response to acetylcholine, to substance P, to prostaglandin F2 alpha and to KCl was unaffected by 10 microM GM-109 in the same preparation. Both GM-109 and pMTL competitively inhibited 125I-pMTL binding to motilin receptors in a homogenate of the rabbit small intestinal smooth muscle tissue. The pKi value of GM-109 and the pKd value of unlabeled pMTL were 7.99 +/- 0.04 and 9.25 +/- 0.06 (each n = 5), respectively. These results indicate that GM-109 is a selective and competitive motilin receptor antagonist in the smooth muscle of the rabbit small intestine. Thus this compound may be a useful pharmacological tool for examining the functional role(s) of motilin.

Amino Acid Sequence↗

PubMed1994

Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. III. 4-[2-(5-ethyl-2-thienyl)]-2'-[2-(1-imidazolyl)ethyl]-1(2H)- phthalazinones.

Synthesis and pharmacological evaluation of novel 4-[2-(5-ethyl-2-thienyl)]-2-[2-(1-imidazolyl)ethyl]-1(2H)-phthalazinone s are described. The phenyl moiety of the phthalazinone skeleton was found to play an important role in both thromboxane A2 synthetase-inhibitory and bronchodilatory activities.

Animals↗

PubMed1994

Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. IV. 2-[2-(1-Imidazolyl)ethyl]-4-(3-pyridyl)-1(2H)-phthalazinones.

Synthesis and pharmacological evaluation of several compounds related to 2-[2-(1-imidazolyl)ethyl]-4-(3-pyridyl)-1(2H)-phthalazinones are described. The phenyl moiety of the phthalazinone skeleton was found to play an important role in both thromboxane A2 synthetase-inhibitory and bronchodilatory activities. Further, the 3-pyridyl group at the 4-position was shown to be necessary for in vivo thromboxane A2 synthetase-inhibitory activity.

Animals↗

PubMed1993

Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. 1. 2-[2-(1-Imidazolyl)alkyl]-1(2H)-phthalazinones.

A number of 4-substituted 2-[omega-(1-imidazolyl)alkyl]-1(2H)-phthalazinones were synthesized in order to develop agents possessing both thromboxane A2 synthetase inhibitory and bronchodilatory activities. The pharmacological evaluation of these compounds disclosed that they have both activities to various extents. Both activities were slightly dependent on the length of the 2-substituents and largely affected by the nature of the 4-substituents. Compounds bearing phenyl and thienyl groups exhibited relatively high and well-rounded activities. Among these compounds, 12j and 15f were found to be the most effective agents having well-rounded activities in vitro and in vivo. Introduction of a carboxyl group reduced both activities contrary to our expectation. 4-(3-Pyridyl)phthalazinone 18b was of particular interest because of unexpectedly high in vivo activities in spite of an absence of significant in vitro activities.

Animals↗

PubMed1993

Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. 2. 4-(3-Pyridyl)-1(2H)-phthalazinones.

A series of novel 4-(3-pyridyl)-1(2H)-phthalazinone derivatives which possess dual activities of thromboxane A2 (TXA2) synthetase inhibition and bronchodilation was synthesized, and their pharmacological activities were evaluated. While the length and the bulk of 2-alkyl substituents had no influence on either activity, the 2-substituents with polar groups reduced bronchodilatory activity. Furthermore, we introduced heteroaromatic nuclei into the 4-position of the phthalazinone and found that 1-imidazolyl (13a) and 5-thiazolyl (16b and 16c) derivatives were as active as the parent 3-pyridyl compound 5b. These findings suggest that heteroaromatic nuclei at the 4-position of phthalazinones play a critical role in TXA2 synthetase inhibition. Additionally, the hydrophobicity of the compounds was found to exert a marked influence on bronchodilatory activity. These observations led to the selection of 2-ethyl-4-(3-pyridyl)-1(2H)-phthalazinone (5b) (KK-505) and 2-methyl-4-(5-thiazolyl)-1(2H)-phthalazinone (16b) (KK-562) for further studies. Although their precise mechanism of action remains unclear, this series of novel phthalazinone derivatives represents a new class of antiasthma agents with dual activities.

Animals↗

PubMed1993

Comparative studies with 15(R)-15-methylprostaglandin E2 (arbaprostil) in rat femoral arterial preparations in vivo and in vitro.

1. The vasodilator responses to 15(R)-15-methylprostaglandin E2 (arbaprostil), prostaglandin (PG) E2 and acetylcholine (ACh) administered into the femoral artery intra-arterial (i.a.) of anesthetized rats were attenuated by i.a. infusion of methylene blue, while that to nicardipine remained unaffected in the same dose-range of methylene blue. 2. The vasocontractor responses to arbaprostil and PGE2 in isolated femoral arterial strips were significantly potentiated by removal of the endothelium and the presence of NG-monomethyl L-arginine, while that to U-46619 remained unaffected under the same condition. 3. The present result indicates that the endothelium-dependent mechanism may play an important role in the vascular response to arbaprostil, like PGE2 and ACh.

Acetylcholine↗

PubMed1992

Spasmolytic action of nicorandil in canine conductive coronary arteries in vivo is not modified by glibenclamide.

The spasmolytic effects of nicorandil, cromakalim, and nitroglycerin on coronary arteries were investigated by angiographic technique in anesthetized dogs. With intracoronary arterial (i.a.) U 46619, a thromboxane A2 mimetic, the diameter of coronary arteries decreased in a sustained manner by 36.1 +/- 1.6% from control levels (coronary spasm). With a successive i.a. injection of nicorandil (300 micrograms), cromakalim (30 micrograms), or nitroglycerin (3 micrograms), the diameter recovered control levels (102.9 +/- 3.9, 96.8 +/- 5.6, and 100.1 +/- 4.3%, respectively). In dogs treated intravenously (i.v.) with glibenclamide, a pharmacologic antagonist of K-channel openers, the spasmolytic effect of cromakalim was significantly reduced, whereas the activity of nicorandil or nitroglycerin remained unaffected. We also investigated a possible modification by glibenclamide of the increase in coronary blood flow (CBF) induced by i.a. nicorandil and cromakalim in anesthetized dogs. The dose-dependent blood flow responses to cromakalim and nicorandil were significantly attenuated by glibenclamide, whereas the response to nitroglycerin remained unaffected. These results suggest that the spasmolytic effect of nicorandil on canine conductive coronary vessels is not mediated by K-channel opening but by a nitroglycerin-like action and that the dilatation of resistive coronary vessels induced by nicorandil may be largely due to its action as a K-channel opener.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed1992

Effects of cisapride on gastrointestinal motor activity and gastric emptying of disopyramide.

The effects of cisapride on the gastrointestinal contractile activity and pharmacokinetics of disopyramide were determined in beagle dogs and patients with arrhythmia. In the animal experiments, the gastric motor index was significantly decreased by i.v. administration of disopyramide in a dose-dependent fashion. The peak decrease of the motor index was observed within 5 min after i.v. injection of disopyramide; the motor index then recovered gradually to the level present prior to drug administration. I.v. administration of cisapride (0.5 mg/kg) markedly increased gastrointestinal contractile activity following the decrease induced by disopyramide pretreatment (5 mg/kg, i.v.). In the clinical studies, the gastric emptying test was performed using the acetaminophen method. A significant correlation between plasma concentrations of disopyramide and gastric emptying time has been found (p < 0.001). The combination of disopyramide (100 mg t.i.d.) and cisapride (2.5 mg t.i.d.) significantly increased gastric emptying compared with that induced by disopyramide alone. The peak plasma concentration of disopyramide in association with cisapride oral administration was significantly higher, and the apparent absorption rate constant and lag time of disopyramide were about 2-fold higher and 2-fold shorter, respectively, than for disopyramide alone. Cisapride, acting as a cholinergic agonist, may counteract the anticholinergic effect of disopyramide on gastric motility. As a factor influencing drug absorption, gastric emptying is of importance, as it determines the rate of drug delivery to the small intestine. Therefore, the oral administration of disopyramide with cisapride may be useful for patients with delayed gastric emptying.

Administration, Oral↗

PubMed1992

Protective effects of arbaprostil against indomethacin-induced gastric lesions in rats: significance of maintained gastric blood flow.

The purpose of the present study was to investigate the relationship between the effects of 15(R)-15-methylprostaglandin E2 (arbaprostil) on gastric blood flow (GBF) and its protective effects on gastric lesions in rats. The GBF of anesthetized rats was measured by two different methods: Total blood flow into the stomach (total GBF) was determined by means of an ultrasonic pulsed Doppler flow meter; and gastric mucosal blood flow (mucosal GBF) was measured by nonradioactive microspheres. Systemic blood pressure (SBP), heart rate (HR) and gastric vascular resistance (GVR) were recorded simultaneously. Arbaprostil (10-100 micrograms/kg) given i.v. did not affect resting total or mucosal GBF even though it decreased SBP and GVR. Significant improvement of the total and mucosal GBF decreased by indomethacin pretreatment (10 mg/kg, i.v.) was observed by administration of arbaprostil (10-100 micrograms/kg, i.v.) in a dose-dependent manner. Furthermore, i.v.-administration of this agent, in the same dose-range, prevented the formation of gastric lesions induced by indomethacin. The present result suggests that mitigation for the ischemic state of the gastric mucosa may be one of the important mechanisms for the prophylactic and curative effect of arbaprostil on gastric lesions induced by indomethacin.

Animals↗

PubMed1991

Acid-promoted epimerization of arbaprostil, 15(R)-15-methylprostaglandin E2, elicits gastric antisecretory activities in rats.

Gastric acid antisecretory activities of 15(R)-15-methylprostaglandin E2 (arbaprostil) preincubated or not preincubated with 0.9% physiological saline, the pH of which was precisely adjusted to less than 4.30, were examined in pylorus-ligated rats, and compared with those of 15(S)-15-methylprostaglandin E2 (15(S), epimer of arbaprostil). 15(S), unlike arbaprostil without preincubation, when s.c.-administered to rats significantly inhibited gastric acid secretion in a dose-dependent manner (30-300 micrograms/kg). However, arbaprostil preincubated at 37 degrees C for 30 min with 0.9% saline, at pHs of 4.30, 2.75 and 1.20, respectively, showed the following order of pH-dependent antisecretory activities: 1.20 greater than 2.75 greater than 4.30. An increase in 15(S) formation from arbaprostil in a pH-dependent manner was also observed by radioisotopic experiments under the same incubation conditions using [3H]-labeled arbaprostil. The present result suggests that the gastric antisecretory effect of arbaprostil can be mainly explained in terms of the formation of 15(S) after oral administration.

Administration, Oral↗

PubMed1989

In vivo experiments for the evaluation of alpha 1-adrenoceptor antagonistic effects of SGB-1534 on canine urethra.

The alpha 1-adrenoceptor blocking effects of SGB-1534 on the urethral smooth muscle were compared in in vivo lower urinary tract preparations of anesthetized dogs, with the effects of other alpha 1-adrenoceptor antagonists, prazosin and bunazosin. Hypogastric nerve stimulation and selective administration of phenylephrine to the urethra and bladder through the cannulated right external iliac artery (i.a.) elicited reproducible frequency- and dose-dependent increases in intra-urethral pressure. Intra-bladder pressure was increased by the nerve stimulation but not by i.a. phenylephrine. SGB-1534, prazosin or bunazosin (0.1-10 micrograms/kg i.v.) dose dependently suppressed the urethral contraction evoked by the nerve stimulation and i.a. phenylephrine but did not influence the bladder contraction elicited by nerve stimulation. The alpha 1-adrenoceptor blocking potency of SGB-1534 was approximately 2.3 and 8.1 times greater than that of prazosin and bunazosin, respectively. The results indicate that alpha 1-adrenoceptors may mediate mainly the urethral contraction induced by hypogastric nerve stimulation and i.a. phenylephrine, and that SGB-1534 was more potent alpha 1-adrenoceptor blocking activity than prazosin and bunazosin in the canine urethra.

Adrenergic alpha-Antagonists↗

PubMed1989

Functional evaluation of sympathetically mediated responses in in vivo lower urinary tract of dogs.

An in vivo procedure for evaluating local effects of alpha-adrenoceptor stimuli on the lower urinary tract was developed in anesthetized dogs. Electrical stimulation of hypogastric nerve at varied frequencies (1, 2, and 4 Hz) and intraarterial (i.a.) administration of an alpha 1-adrenoceptor agonist, phenylephrine (0.3, 1, and 3 micrograms) to the urethra and bladder through the cannulated right external iliac artery caused reproducible frequency- or dose-related increases in intraurethral pressure (IUP). Intrabladder pressure (IBP) was increased by the nerve stimulation but not by i.a. phenylephrine. Acetylcholine (10 micrograms) given i.a. elicited increases in both IUP and IBP. Prazosin (0.1, 1, and 10 micrograms/kg, i.v.) dose-dependently suppressed the urethral contractile responses to the nerve stimulation and i.a. phenylephrine, but it failed to affect the bladder contraction evoked by the nerve stimulation. The results suggest that the urethral contractile responses to hypogastric nerve stimulation as well as i.a. phenylephrine were mediated via alpha 1-adrenoceptors, whereas the IBP increasing effect of hypogastric nerve stimulation was not mediated via alpha 1-adrenoceptors.

Acetylcholine↗

PubMed1989

[Central pontine myelinolysis followed by frequent hyperglycemia and hypoglycemia--report of an autopsy case].

A case of central pontine myelinolysis (CPM) followed by hyperglycemia and hypoglycemia was reported. The case was 53-year-old female. Diabetes mellitus was found when she was 32 years old, insulin therapy was started at 37 years of age. Since she was 50 years old, proteinuria and ankle edema had developed and she was admitted to The Keihin Hospital. The peritoneal dialysis (PD) was performed next year, followed by the hemodialysis (HD). In January 1978, strange movements and the disturbance of her consciousness were occurred during PD, then blood glucose level showed over 1,800 mg/dl and serum osmolarity was over 390 mosm/KgH2O. Then she was diagnosed as non-ketotic hyperosmolar coma. After that, during HD and PD, hyperglycemia (approximately 1,200 mg/dl) and hypoglycemia (approximately 40 mg/dl) developed frequently. She died soon after HD on 19th December 1979. The autopsy disclosed bilateral atrophic kidneys due to diabetic changes and atrophic pancreas. Gross neuropathological findings revealed a few small infarcts at the putamen and the globus pallidus, however, other area were observed to be normal. The most remarkable change in microscopical finding was nearly symmetrical demyelinative lesion in the center of the basis pontis. The nerve cells and axon cylinders were relatively well preserved in the demyelinative lesion. The hyaline degeneration was observed in the arterial wall, however, any arterial obstruction was not found. Recent studies would suggest that the electrolyte disturbance, such as hyponatremia, may lead to CPM, particularly when this disturbance was rapidly corrected. On the other hand, CPM induced by diabetic coma has been reported, however, its pathogenesis has been unclear.(ABSTRACT TRUNCATED AT 250 WORDS)

Demyelinating Diseases↗

PubMed1988

A research method for MRI tissue characterization studies using small coils for excised organs.

The main purpose of this report is to describe our method of MRI tissue characterization studies, which consists of MR imaging of the patient, precision MR imaging of the excised organ, and pathological examination of the organ. We first made small coils to be used with conventional MRI scanners to examine the excised organs. In order to make it easier to understand the effectiveness of our method, three illustrative case reports of abdominal or pelvic tumors were presented as examples of the tissue characterization studies. In conclusion, this method seemed very useful and, in addition, it was found that this small coil technique has several advantages in other applications.

Abdominal Neoplasms↗