Biomedical subjects

M Kodama

Publications and source records attributed to M Kodama.

At least 109 records · Page 6Linked to original sources

PubMed1999

Effects of YM90K, a selective AMPA receptor antagonist, on amygdala-kindling and long-term hippocampal potentiation in the rat.

To investigate the role of alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) type glutamate receptors in epileptic seizures, we examined the antiepileptogenic and anticonvulsant effects of YM90K [6-(1H-imidazol-1-yl)-7-nitro-2,3-(1H,4H)-quinoxalinedione hydrochloride], a potent and selective new AMPA receptor antagonist, in the rat amygdala-kindling model of epilepsy. Pretreatment with YM90K (7.5-30 mg/kg i.p.) markedly retarded the evolution of kindling. Once kindling was established, administration of YM90K (7.5-30 mg/kg i.p.) significantly and dose-dependently suppressed fully kindled seizures. The maximal effects were observed 15-30 min after injection. When the intensity of electrical stimulation was increased to twice the generalized seizure-triggering threshold, the anticonvulsant effects of YM90K were reversed, suggesting that they were due to elevation of the generalized seizure-triggering threshold. Furthermore, an anticonvulsant dose (15 mg/kg) of YM90K affected neither field potentials nor long-term potentiation in the hippocampus in vivo. These results indicate that AMPA receptors play an important role in the seizure expression mechanism and the development of kindling-induced epileptogenesis, and suggest the possible clinical usefulness of AMPA receptor antagonists as antiepileptic drugs.

Amygdala↗

PubMed1999

The mechanisms of simultaneous stereoinversion, racemization, and isomerization at specific aspartyl residues of aged lens proteins.

Proteins have been considered to consist exclusively of L-amino acids in living tissues. However, we found biologically uncommon D-aspartyl (Asp) residues at specific sites in alphaA- and alphaB-crystallin from the aged human lens (mean age: 80 years). In alphaB-crystallin, the Asp-36 and Asp-62 residues are highly racemized (D/L ratios: 0.92 for Asp-36; 0.54 for Asp-62). More interestingly, the configuration of the Asp-58 and Asp-151 residues in alphaA-crystallin is inverted to the D-isomer (D/L ratio: 3.1 for Asp-58, 5.7 for Asp-151). A D/L ratio > 1.0 is not considered to be due to racemization, but rather is thought to result from stereoconfiguration inversion. Our report was the first observation that inversion occurred in the configuration of amino acids in vivo during the natural aging process. We also found that these enantiomers were simultaneously isomerized to form beta-Asp residues. We propose that the mechanism of D- and beta-Asp formation in the protein depends on the primary structure and the presence of a chiral reaction field, which induces formation of D-Asp.

Aged↗

PubMed1999

Effects of deletion-type human hepatocyte growth factor on murine septic model.

BACKGROUND: Sepsis is known to be the main cause of multiple organ failure. The liver especially is vulnerable to the stress of infection. In this study, the effects of deletion-type human hepatocyte growth factor (dHGF) on a murine septic model were studied. MATERIALS AND METHODS: Sepsis was induced in male adult Sprague-Dawley rats by cecal ligation and puncture method (CLP). Controls were given a sham operation. Intravenous injection of 1000 micrograms/kg dHGF or the same volume of vehicle was given every 12 h for 3 days before and/or after the CLP from a central vein catheter inserted 1 week prior to the operation. The daily percentage of survival after CLP was followed up for 1 week, and blood samples and liver specimens were collected from the surviving animals 72 h after CLP or sham operation. RESULTS: The survival rate, the degree of liver damage and liver protein synthesis, and coagulation function were all favorable in the dHGF-treated animals compared to the untreated animals. Immunohistochemical staining showed that dHGF prevented the disappearance of thrombomodulin (TM) in liver sinusoid endothelium. CONCLUSIONS: dHGF appears to prevent liver injury caused by disturbance of microcirculation through preservation of TM expression and the antithrombotic function in the endothelium of sinusoids. dHGF also facilitates repair of damaged hepatic tissue by stimulating regeneration of the cells and by preserving hepatic functions such as protein synthesis. dHGF exerts protective effects on even quiescent hepatocytes, but is most effective on injured but competent hepatocytes.

Animals↗

PubMed1999

Handlebar hernia with intra-abdominal extraluminal air presenting as a novel form of traumatic abdominal wall hernia: report of a case.

An 18-year-old male was admitted to our Emergency Department with a traumatic abdominal wall hernia (TAWH) of the left lower quadrant (LLQ) after suffering hypogastric blunt injury and urogenital lacerations in a motorcycle accident. Upright chest X-ray showed a small amount of right infradiaphragmatic free air, and a computed tomographic (CT) scan demonstrated an abdominal wall hernia. At surgery, no impairment was found in the digestive tract, and an abdominal herniorrhaphy was performed. It is suggested that the free air had passed through a connection between the scrotal laceration and the contralateral abdominal defect via the subcutaneous space and was palpated as emphysema. This is a new type of TAWH, which suggests that blunt abdominal trauma may result in negative pressure in the subcutaneous and peritoneal cavity, and this could reflect the pathophysiology of TAWH.

Abdominal Muscles↗

PubMed1999

Familial hyperparathyroidism: report of a case.

We report herein a case of familial primary hyperparathyroidism diagnosed in a 23-year-old woman who presented with hypercalcemia and urolithiasis. The parathyroid gland was removed, and pathological examination revealed chief cell adenoma. The proband's younger sister had undergone surgery for parathyroid adenoma at the age of 19, and her aunt had a history of urolithiasis with a high level of serum parathyroid hormone. We have not yet found evidence of any other endocrine disorders suggesting multiple endocrine neoplasia (MEN) type 1 in this pedigree.

Adenoma↗

PubMed1999

Abnormal fatty acid metabolism in patients with coronary vasospasm.

Although various noninvasive methods have been used to detect vasospasm, none of them are sensitive enough for patients with sporadic attacks. Since abnormal fatty acid metabolism is observed in ischemic myocardium, 123I-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP), a radiolabeled fatty acid analog, has recently been proposed as a useful tracer for detecting myocardial damage. The aim of this study was to clarify the clinical implications of decreased myocardial BMIPP uptake in patients with vasospastic angina. We evaluated 53 patients with vasospastic angina (32 with clinically documented vasospasm [Group-A] and 21 with vasospasm induced by ergonovine provocation [Group-B]) and 27 control subjects, 20 in Group-A were re-evaluated 6 months after medical treatment. The territorial regions of vasospasm-induced coronary artery, the wall motion by left ventriculography, and BMIPP uptake were compared. Vasospasm was induced in multiple coronary arteries in 29 (55%) patients. Reduced wall motion and decreased BMIPP uptake were observed in 19 (36%) patients and 47 (89%) patients, respectively. The sensitivity and specificity of determination of vasospasm-induced coronary arteries with BMIPP scintigraphy were 71% (69/97 coronary arteries) and 88% (126/143), respectively. Vasospasm was re-induced by ergonovine provocation in 8 patients (Group-I) and not re-induced in 12 (Group-II) after treatment. In Group-I, improvement of decreased BMIPP uptake was lower than in Group-II (19+/-11 vs. 59+/-22%, mean+/-SD, p < 0.001). The regions in which vasospasm was re-provoked exhibited decreased BMIPP uptake. Abnormal fatty acid metabolism was more often observed than wall motion abnormality in the vasospastic region in patients with vasospastic angina. BMIPP scintigraphy is a highly accurate and non-invasive technique for determining the presence and location of vasospasm.

Adult↗

PubMed1999

Molecular karyotypes for Alternaria plant pathogens known to produce host-specific toxins.

There are at least ten plant diseases caused by Alternaria species in which host-specific toxins (HSTs) are responsible for fungal pathogenicity. Of these HST-producers, seven are considered distinct pathotypes of the species Alternaria alternata, and the remaining three are among other species of pathogenic Alternaria. Inter- and intra-specific variation among Alternaria taxa, including HST-producers, was determined by electrophoretic karyotyping using pulsed-field gel electrophoresis. A. alternata including seven pathotypes of A. alternata and eight non-pathogenic strains had 9-11 chromosomal bands with estimated sizes ranging from 0.4 to 5.7 Mb. In contrast, Alternaria species that are morphologically distinct from A. alternata had 8-10 bands with sizes between 0.9 and 5.7 Mb. Estimated genome sizes of A. alternata and other Alternaria species ranged from 28.8 to 33.6 Mb and 25.1 to 30.7 Mb, respectively. Other species of pathogenic Alternaria were difficult to differentiate from A. alternata on the basis of chromosome-size polymorphisms alone, but Southern analysis using rDNA as a probe could, in some cases, differentiate between them. These results were cytologically confirmed by 4',6-diamidino-2-phenylindole (DAPI) staining and fluorescence in situ hybridization with a rDNA probe for mitotic metaphase chromosomes prepared by the germ-tube burst method.

Alternaria↗

PubMed1999

Abdomino-sacral approach for coloanal anastomosis for lower rectal cancer.

The abdomino-sacral approach is an important and essential procedure for surgery on a recto-anal lesion. The sacral approach had been applied since the former century, but the abdomino-sacral approach was not completely established. The sacral wound dehiscence is a common associated morbidity. It is very difficult for a surgeon who needs this procedure to find a text that contains all the techniques required. Thus, most surgeons have not understood this procedure, and have not known the capabilities of and indications for this approach. The abdomino-sacral approach to lower rectal cancer and/or lesions located there, is described. Especially advantages such as the improved skin incision and the colo-anal anastomosis using this approach are mentioned.

Abdomen↗

PubMed1999

Confirmation of domoic acid production of Pseudo-nitzschia multiseries isolated from Ofunato Bay, Japan.

Production of domoic acid (DA), the responsible toxin for amnesic shellfish poisoning, was examined for 44 strains of Pseudo-nitzschia spp. isolated from Ofunato Bay, Japan. Only one strain which was identified as Pseudo-nitzschia multiseries produced DA in a level comparable to Canadian strains. No significant DA was detected in the rest of the strains, indicating that toxic P. multiseries does not bloom in a high density in the bay.

Canada↗

PubMed1999

Platelet adhesion and complement activation studies on poly(N-alkyl mono and disubstituted) acrylamide derivatives.

Poly(N-alkyl mono and disubstituted) acrylamide derivatives were synthesized from poly(acryloyl chloride) by monomer analogous reaction. The polymers were characterized by FTIR-ATR and GPC. The contact angle measurements were performed to evaluate hydrophobic/hydrophilic characters of these polymers. The N-alkyl substituents changed contact angle between 55 and 75 degrees. In vitro platelet adhesion studies showed that surfaces of poly(N-alkyl substituted) acrylamides are prone to adhere platelets. Platelet spreading was more on poly(N-benzyl-N-ethyl acrylamide) surfaces in comparison to that on poly(N-benzyl-N-propionic acid ethyl ester acrylamide) and poly(N-benzyl acrylamide) surfaces. As a result of modification of amino group with N-alkyl substituents, the activations of C3a and C5a complements were suppressed 9-20% and 5-6% of native poly(acrylamides), respectively.

Acrylates↗

PubMed1999

Adrenomedullin promotes epithelial restitution of rat and human gastric mucosa in vitro.

We have investigated the effect of adrenomedullin (AM) on restitution of mucosal integrity following damage in rat and human gastric mucosa, measuring the potential difference (PD) on a mucosal strip mounted on an Ussing chamber. Mucosal damage was induced by 0.5, 1.0, and 2.0 M NaCl solution, and it caused an immediate and significant decrease in PD. In the rat AM group, PD recovered significantly more than in control group at 120 min after exposure to 0.5 M (p < 0.01) and 1.0 M (p < 0.05) NaCl solution. In the human AM group, PD completely recovered at 120 min after exposure to 0.5 M (p < 0.05) NaCl solution. In rat mucosa damaged by 0.5 M NaCl solution, the effect was inhibited by human (h)-CGRP(8-37) and there was no significant difference between the h-CGRP(8-37) group and control group. On immunohistochemical examination of rat gastric mucosa, AM was detected within the chief cell. AM probably promotes epithelial restitution primarily through the CGRP receptor, but it does not ameliorate more severe damage of gastric mucosa in vitro.

Adrenomedullin↗

PubMed1999

Chemical conversion of vibsanin C to vibsanin E and structure of 3-hydroxyvibsanin E from viburnum awabuki

Vibsanin E (4), a tricyclic vibsane-type diterpene, has been prepared in 50% yield from vibsanin C (2), a seven-membered ring vibsane-type diterpene by reaction with BF3.OEt2 at -78 degrees C. This chemical correlation not only established structure, including absolute configurations, but also has demonstrated a possible biosynthetic route to 4 via 2 derived from vibsanin B (1). The structure of 3-hydroxyvibsanin E (5), another example of a tricyclic seven-membered ring vibsane, isolated from the leaves of Viburnumawabuki, has been established by extensive analyses of 2D NMR data and comparison of its spectral data with those of 4.

Journal Article↗

PubMed1999

Skin blood flow responses during sleep by laser Doppler flowmetry.

Skin surface blood flow at the fingertips was measured in a 21-year-old woman during sleep using laser Doppler flowmetry. Skin blood flow responses (SBFR) are transient reductions in skin blood flow of about 25s in duration. In our subject, SBFR showed a delay time of 8-9s from the onset of skin potential responses (SPR) and appeared more consistently than SPR. The frequency of SBFR decreased during non-rapid eye movement sleep, especially when the sleep stage became deep. These findings indicate the validity of SBFR as a discrete index of autonomic function during sleep.

Adult↗

PubMed1999

Antitumor effect of cisplatin incorporated into polylactic acid microcapsules.

Cisplatin containing microcapsules (CDDP-MC) were prepared by encapsulating cisplatin suspended in a dispersing agent in a copolymer (lactic acid) matrix using an in water drying method. Cisplatin release from the microcapsules was controlled by the addition of albumin. The CDDP-MC were relatively stable in storage, and there was only minimal initial release of the cisplatin from the microcapsules. The antitumor effects of this sustained release dosage form of cisplatin were evaluated in vitro and in vivo in mice. Mice were given an intraperitoneal (i.p.) injection of CDDP-MC 24 h after inoculation with tumor cells. The CDDP-MC were effective against Ehrlich ascites tumors and showed reduced acute toxicity compared with standard cisplatin solution. Due to the small initial release of the cisplatin from the microcapsules, however, the antitumor effect of the CDDP-MC was weaker than that of cisplatin solution. Conventional sustained release preparations have been reported to have large particle sizes and demonstrate large releases of cisplatin from microcapsules. They have been considered more effective than cisplatin solution because of the large initial release of cisplatin from the microcapsules and the maintenance of drug levels. The antitumor effect of our slow-release formulation of cisplatin was evaluated by administration of CDDP-MC 1, 4, and 7 days before i.p. implantation of tumor cells. The survival time of the tumor-bearing mice was prolonged in the CDDP-MC group, but not in the group treated with cisplatin solution. By using this modified formulation of cisplatin, the toxicity of the drug can be reduced, and effective concentrations of the drug can be maintained locally for prolonged periods of time.

Animals↗

PubMed1999

Bioartificial liver support system using porcine hepatocytes entrapped in a three-dimensional hollow fiber module with collagen gel: An evaluation in the swine acute liver failure model.

The perfusion culture system of hepatocytes entrapped in a three-dimensional hollow fiber module with collagen gel is expected to realize an effective bioartificial liver (BAL) support system. The BAL module contained 5.4 billion porcine hepatocytes, which is approximately 7% of the total liver, supplied adequate metabolic functions, and improved the survival of the experimental acute liver failure swine. Improvement of the prothrombin time by the BAL treatment was not significant; however, the bleeding tendency was suppressed, which resulted in a significantly prolonged survival time of the animals in the BAL treatment group. A drastic up-regulation of the expression of the mRNA for plasminogen activator inhibitor 1 (PAI-1), which is known as an inhibitor for fibrinolysis, may explain the suppression of the bleeding tendency. These results support the efficacy of our BAL system for the treatment of acute liver failure.

Animals↗

PubMed1999

Aminoguanidine has both an anti-inflammatory effect on experimental colitis and a proliferative effect on colonic mucosal cells.

BACKGROUND: The aim of this study was to assess the effect of aminoguanidine (AG) on developed colitis and cell proliferation. METHODS: Colitis was induced by means of trinitrobenzene sulphonic acid (TNB) in male Wistar rats weighing about 250 g. Seven days after induction of TNB colitis the rats were divided into two groups at random, and one group was orally treated with 1.5 micromol/kg AG each day. We assessed the effect of AG by measuring the mucosal damage, the ulcer area, myeloperoxidase (MPO) activity, inducible nitric oxide synthase (iNOs) activity, and nitrogen oxide in serum 7 days after the beginning of treatment. RESULTS: AG significantly ameliorated the macroscopic damage score (AG versus control, 5.25 +/- 0.80 versus 7.50 +/- 0.50), the microscopic damage score (5.88 +/- 1.13 versus 9.25 +/- 0.31), ulcer area (0.57 +/- 0.14 versus 1.24 +/- 0.17 cm2), decreased MPO activity (51.5 +/- 9.4 versus 192.2 +/- 60 units/g tissue), and nitrogen oxide in serum (27.2 +/- 1.4 versus 32.3 +/- 1.8 microM) but did not decrease iNOs activity (8732 +/- 435 versus 8672 +/- 357 cpm/g tissue). Moreover, AG accelerated T84 cell proliferation in a dose-dependent manner. CONCLUSIONS: These results suggest that AG ameliorates TNB colitis not only by its anti-inflammatory effect but also by accelerating the proliferation of colonic mucosal cells. AG, accordingly, might well be a useful new medicine to ameliorate inflammatory bowel disease.

Analysis of Variance↗

PubMed1999

The translocation-associated tox1 locus of Cochliobolus heterostrophus is two genetic elements on two different chromosomes.

Previously, Tox1 was defined as a single genetic element controlling the difference between races of Cochliobolus heterostrophus: race T is highly virulent on T-cytoplasm corn and produces the polyketide T-toxin; race O is weakly virulent and does not produce T-toxin. Here we report that Tox1 is two loci, Tox1A and Tox1B, on two different chromosomes. Evidence for two loci derives from: (1) the appearance of 25% Tox+ progeny in crosses between induced Tox1(-) mutants, one defective at Tox1A, the other at Tox1B; (2) the ability of Tox1A- + Tox1B- heterokaryons to complement for T-toxin production; and (3) electrophoretic karyotypes proving that Tox1(-) mutations are physically located on two different chromosomes. Data showing Tox1 as a single genetic element are reconciled with those proving it is two loci by the fact that Tox1 is inseparably linked to the breakpoints of a reciprocal translocation; the translocation results in a four-armed linkage group. In crosses where the translocation is heterozygous (i.e., race T by race O), all markers linked to the four-armed intersection appear linked to each other; in crosses between induced Tox1(-) mutants, complications due to the translocation are eliminated and the two loci segregate independently.

Ascomycota↗

PubMed1999

Retroperitoneal germ cell tumor treated by PVeBV chemotherapy: a case report.

The extragonadal germ cell tumor are uncommon neoplasms which account for only 1-5% of germ cell tumors, and its prognosis is poor. We report here the use of combination chemotherapy with cisplatin, etoposide, bleomycin, and vinblastine (PVeBV) for the treatment of retroperitoneal germ cell tumor. A 28-year-old male with complaints of abdominal pain and lumbago, without any abnormality in both testes by physical and ultrasonographic examination, showed retroperitoneal tumor by abdominal computed tomography. The serum alpha-fetoprotein and lactate dehydrogenase were elevated. The retroperitoneal tumor was treated surgically. The pathological diagnosis was mixed germ cell tumor. The lung and supraclavicular lymph node metastases disappeared completely after 3 courses of PVeBV chemotherapy with cisplatin (40 mg/m2 per day) and etoposide (100 mg/m2 per day) for 5 consecutive days, with vinblastine (0.2 mg/kg) on day 1, and bleomycin (30 mg/body) given on days 1, 8, and 15. Granulocyte colony-stimulating factor and serotonin receptor antagonist application were available on acute phase toxic effects. The patient is now alive and well, without recurrence, more than 26 months after the operation.

Adult↗