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T Koyama

Publications and source records attributed to T Koyama.

At least 163 records · Page 9Linked to original sources
PubMed2000

Antibody reactivity to Cryptosporidium parvum in saliva of calves after experimental infection.

Antibodies against Cryptosporidium parvum in the saliva and sera of three calves experimentally infected with this parasite were examined by an indirect immunofluorescence antibody test and immunoblotting. Salivary anti-C. parvum IgA antibody appeared on day 12 post-challenge and had a tendency to increase transiently between days 15 and 30 post-challenge. Salivary anti-C. parvum IgG antibody levels showed a gradual increase along with the change in IgA antibody levels during the infection. In contrast, serum anti-C. parvum IgA antibody levels showed only a slight increase between days 15 and 30 post-challenge. Serum anti-C. parvum IgG antibody levels rose on day 12 post-challenge and one calf maintained relatively high level up to the end of the experiment. In immunoblotting, an antigen with a molecular mass of 15 kDa was found to react strongly to salivary IgA antibody and a 27 kDa antigen to react to serum IgG antibody.

Animals↗
PubMed2000

An occurrence of Salmonella typhimurium infection in sika deer (Cervus nippon).

Seven sika deer (Cervus nippon) in a herd of 30 deer in a park died. Upon examination of three dead deer, Salmonella Typhimurium was isolated from the organs and intestinal contents. Histopathological examination revealed catarrhal enteritis and focal necroses in the liver. Immunohistochemically, Salmonella antigen of O4 was detected in the enteric lesions. The case was diagnosed as S. Typhimurium infection in the sika deer. Because of the importance of Salmonella in public health, fecal and soil samples were continuously collected from the paddock. However, no Salmonella was isolated from any samples collected after medication of the deer and thorough disinfection of the immediate environment.

Animals↗
PubMed2000

Salmonella virchow infection in an infant transmitted by household dogs.

A 4-month-old male infant manifested diarrhea and Salmonella Virchow was isolated from his stool. The pathogen was repeatedly isolated from the infant over one month despite three regimens of treatment with antibiotics, to which the isolate was sensitive. Three household dogs were kept in his home and S. Virchow was isolated from two of them. The infant was admitted to hospital and was treated with antibiotic, then the pathogen was finally eliminated. Antibiotic sensitivity pattern and PFGE pattern produced by restriction enzyme Xba I of the isolate from the infant was completely similar to those of the isolates from the dogs. The above findings indicated that the present S. Virchow infection in the infant was transmitted by the household dogs.

Animal Feed↗
PubMed2000

Induction of growth factors in rat cardiac tissue by X irradiation.

To investigate the relationship between angiogenic growth factors and endothelial enzyme activity in capillaries after injury of rat cardiomyocytes caused by X irradiation, 7-week-old male Wistar rats were anesthetized with pentobarbitone and their hearts irradiated (X rays, 20 Gy) through a hole in the lead casing in which they were enclosed. The hearts were excised at 1 h, 1 week and 3 weeks after irradiation. Left ventricular cross sections were stained for capillary enzymes by double staining for two endothelial enzymes, alkaline phosphatase (AP) and dipeptidylpeptidase IV (DPP), immunohistochemically stained for basic fibroblast growth factor (Fgf, also known as bFgf) and vascular endothelial growth factor (Vegf), and stained for nick end-labeling of DNA by the TUNEL method. Staining for distribution of AP in the arteriolar portion was reduced at both 1 and 3 weeks after irradiation with 20 Gy, but staining for DPP in the venular portion was unchanged, suggesting a close relationship between growth factors and injury of the arteriolar capillary portion. Fgf and Vegf proteins were present within the cytoplasm of the cardiomyocytes, or around capillaries, 1 h, 1 week and 3 weeks after irradiation. Many TUNEL-stained cardiomyocyte nuclei were observed at 1 h, but they had decreased markedly at 1 week and had almost disappeared by 3 weeks after irradiation. Thus Fgf and Vegf were induced concomitantly with the decrease in the staining for endothelial AP by 20 Gy X irradiation, which also caused microeffects as indicated by TUNEL staining of many nuclei at 1 h postirradiation.

Animals↗
PubMed2000

[Ultrasonographic findings of carotid arteries in female patients with arteriosclerosis obliterans and aortic aneurysm].

To clarify carotid arterial changes in female patients with arteriosclerosis obliterans (ASO) and aortic aneurysm (AA), ultrasonographic (US) findings of the extra-cranial carotid arteries were studied in 26 patients with ASO (ASO group), and 31 patients with AA (AA group), compared to 38 controls (control group) with neither ASO nor AA. ASO was diagnosed with an ankle pressure index less than 0.9, while AA was done with computed tomography or angiography. Half of the patients with ASO were in stage II of the Fontaine clinical staging, and angiography, performed in 12, showed femoral arterial obstruction in 10. Most AA patients were abdominal aortic aneurysm. Using a high-resolution, real-time, B-mode US instrument, the diameter and wall thickness of the common carotids were measured bilaterally in the end-diastolic phase, and occlusive changes and plaque were estimated. As a risk factor for arteriosclerosis, hypertension, diabetes, hyperlipidemia, and cigarette smoking were assessed, in addition to the age, body height and weight. Mean ages of each group were 73 to 76.3 year-old. There was no significant difference between them in body height and weight. Diabetes, cigarette smoking, and cerebrovascular disease were frequent in the ASO group, whereas ischemic heart disease was frequent in the AA group. US findings revealed that carotid lesions were mostly plaque, and bilateral carotid lesions were significantly more frequent in the ASO and AA groups. The mean wall thickness of the carotids was greater in the AA and ASO groups, although dilated carotid arteries, namely arteriomegaly, was more frequent in the AA group than in the ASO and control groups. Stepwise regression analyses demonstrated that strong correlations were seen between carotid lesion and two variables [vessel diseases (ASO/AA) and cigarette smoking], between carotid diameter and three variables (age, AA, and wall thickness), and between the wall thickness and three variables (age, vessel diseases and diameter). These findings showed that atherosclerosis was not only frequent in female patients with ASO and AA, but arteriomegaly was characteristic in female patients with AA. Therefore, it suggested that circulatory disturbance in whole organs due to arteriosclerosis should be paid attention even in female patients with ASO and AA as well as male patients. Furthermore, it is considered that systemic fragility of the arterial media and ectasia could be present extensively in patients with AA.

Age Factors↗
PubMed2000

Simulation of the surgical manipulation involved in clipping a basilar artery aneurysm: concepts of virtual clipping. Technical note.

Despite recent advances in three-dimensional imaging based on a voxel-rendering method, these techniques do not simulate the morphological changes that occur during surgery. The authors' goal was to develop a computer-graphics model to simulate the manipulation that occurs during surgery when clipping a cerebral aneurysm. The authors developed an application program to interpolate the contours of models of an artery and an aneurysm clip. The center of displacement was determined inside the arterial model. The directions of displacement were changed to simulate saccular and broad-neck aneurysms, and the intensity of displacement was calculated by using a cosine-based formula. The morphological changes in a saccular aneurysm that may occur during clipping were calculated in x, y, and z coordinates by using sine- and cosine-based formulas. Clip movement was integrated with the aneurysm model, thus simulating the manipulation used during clipping of a cerebral aneurysm. Surgery performed to clip a basilar artery (BA) aneurysm via the transsylvian approach was simulated, in which displacement of the internal carotid artery and clipping of the BA aneurysm were necessary. The movements of an aneurysm clip and clip applicator were designed to represent those occurring when a surgeon actually manipulates a BA aneurysm. The authors have named this methodological tool "virtual clipping." Use of this tool would assist the preoperative choice of clipping style and selection of the best clip.

Basilar Artery↗
PubMed2000

TGF-beta1 secreted by gastric fibroblasts up-regulates CD44H expression and stimulates the peritoneal metastatic ability of scirrhous gastric cancer cells.

Gastric fibroblast-derived conditioned medium and TGF-beta1 stimulated the adhesion ability of scirrhous gastric cancer cells to mesothelial cells, but not that of well-differentiated gastric cancer cells. The CD44H expression of scirrhous gastric cancer cells was significantly up-regulated by gastric fibroblast-derived CM and TGF-beta1. The stimulated adhesion ability and CD44H expression was significantly inhibited by anti TGF-beta1 neutralizing antibody. These findings suggested that TGF-beta1 secreted by gastric fibroblasts up-regulated the CD44H expression of scirrhous gastric cancer cells, which resulted in the stimulation of the adhesion ability of scirrhous gastric cancer cells to the mesothelium, and increased the peritoneal dissemination potential. These results might explain one of the reasons why scirrhous gastric carcinomas develop frequent peritoneal dissemination.

Adenocarcinoma, Scirrhous↗
PubMed2000

[Advantages of stereotaxic aspiration of intracerebral hematoma using interventional magnetic resonance imaging: new surgical method].

We describe the usefulness of stereotaxic surgery in the brain with special focus on aspiration of intracerebral hematoma using interventional MRI (0.3 Tesla; Hitachi, Japan). A 62-year-old female was admitted to our hospital with sudden right incomplete hemiparesis. A CT scan on admission showed a high-density mass in the left putamen. Soon after admission, her consciousness gradually decreased and the incomplete hemiparesis quickly worsened, so we promptly initiated an operation for stereotaxic aspiration of an intracerebral hematoma. During the surgery, real-time monitoring by MR-fluoroscopy depicted the gradual decrease of the hematoma. Postoperatively, her consciousness recovered to an almost alert level, but her right hemiparesis was unchanged. Stereotaxic aspiration of intracerebral hematoma using interventional MRI is advantageous because it enables accurate and safe evacuation of intracerebral hematoma in real time with no risk of irradiation during the procedure.

Aged↗
PubMed2000

[Microsurgery of cervical intramedullary ependymomas extending into the medulla oblongata].

Intramedullary spinal cord ependymomas are well-demarcated tumors, which can be totally resected without significant morbidity. However, it is challenging to remove intramedullary ependymomas extending into the medulla oblongata, because the medulla oblongata has such important roles as regulation of respiration, circulation, and digestion. We describe here three cases of intramedullary ependymomas extending into the medulla oblongata. The tumors were localized in the dorsal part of the caudal medulla oblongata and were surrounded by the nuclei and tracts related to the dorsal columns. The tumors were safely exposed by dividing the medulla oblongata along the posterior median sulcus and resected from the surrounding normal tissues. Although patients demonstrated transient dorsal column dysfunction postoperatively, the symptom finally recovered.

Adult↗
PubMed1999

Toward the best treatment for uncomplicated patients with type B acute aortic dissection: A consideration for sound surgical indication.

BACKGROUND: In the treatment of type B acute aortic dissection without complications, better results are obtained if surgery is performed before enlargement of the aorta in patients who are predicted to show aortic enlargement and if drug-based treatment is continued for patients who are predicted to show no enlargement. The purpose of this study was to predict the acute-phase factors that may affect chronic-phase aortic enlargement by studying chronic-phase enlargement of dissections in patients without complications during the acute phase. METHODS AND RESULTS: In 101 patients with type B acute dissection who had no complications, univariate and multivariate factor analyses were performed to determine the predictors for chronic-phase enlargement (>/=60 mm) of the dissected aorta. The independent predominant predictors for aortic enlargement in the chronic phase were a maximum aortic diameter of >/=40 mm and a patent false lumen during the acute phase. The values of actuarial freedom from aortic enlargement for the patients with a maximum aortic diameter of 40 mm and a patent false lumen at 1, 5, and 10 years were 43%, 33%, and 22%, respectively, whereas in patients with a maximum aortic diameter of <40 mm and a closed false lumen, the values were 97%, 94%, and 84%, respectively. CONCLUSIONS: These results suggest that patients with type B acute aortic dissection who show a maximum aortic diameter of >/=40 mm and a patent false lumen should undergo surgery earlier during the chronic phase before enlargement of aorta, whereas patients with a maximum aortic diameter of <40 mm and a closed false lumen should continue to receive hypotensive therapy.

Adult↗
PubMed1999

Effect of subchronic lithium carbonate treatment on anxiolytic-like effect of citalopram and MKC-242 in conditioned fear stress in the rat.

We investigated the effect of citalopram [selective serotonin (5-HT) reuptake inhibitor] and MKC-242 (5-[3-¿(2S)-(1, 4-Benzodioxan-2-ylmethyl) amino¿propoxy]-1, 3-benzo-dioxol hydrochloride; a selective 5-HT(1A) receptor agonist) on the expression of conditioned freezing, an index of anxiety, following treatment with subchronic lithium carbonate (LiCO(3)). Male Sprague-Dawley rats were used in these experiments. Acute administration of citalopram (subcutaneously, s.c.) reduced freezing significantly at a high dose (30 mg/kg), while showing no effect at lower doses (3 and 10 mg/kg). Acute administration of MKC-242 (s.c.; 0.1-10 mg/kg) dose dependently reduced freezing. Subchronic LiCO(3) treatment (1 week; 0.05% or 0.2% LiCO(3) in diet; p.o.) showed no effect on freezing behavior. Acute treatment with both citalopram (3 and 30 mg/kg) and MKC-242 (1 mg/kg) after subchronic treatment with the higher, but not the lower concentration of LiCO(3) (1 week), reduced freezing markedly and significantly, as compared with either drug alone. These results suggest that subchronic LiCO(3) treatment enhanced the anxiolytic-like effects of these serotonergic drugs by facilitating central 5-HT neurotransmission at clinically therapeutic plasma lithium levels.

Animals↗
PubMed1999

Site-directed mutagenesis of the conserved residues in component I of Bacillus subtilis heptaprenyl diphosphate synthase.

Heptaprenyl diphosphate synthase of Bacillus subtilis is composed of two dissociable heteromeric subunits, component I and component II. Component II has highly conserved regions typical of (E)-prenyl diphosphate synthases, but it shows no prenyltransferase activity alone unless it is combined with component I. Alignment of amino acid sequences for component I and the corresponding subunits of Bacillus stearothermophilus heptaprenyl diphosphate synthase and Micrococcus luteus B-P 26 hexaprenyl diphosphate synthase shows three regions of high similarity. To elucidate the role of these regions of component I during catalysis, 13 of the conserved amino acid residues in these regions were selected for substitution by site-directed mutagenesis. Kinetic studies indicated that substitutions of Val-93 with Gly, Leu-94 with Ser, and Tyr-104 with Ser resulted in 3-10-fold increases of K(m) values for the allylic substrate and 5-15-fold decreases of V(max) values compared to those of the wild-type enzyme. The three mutated enzymes, V93G, L94S, and Y104S, showed little binding affinity to the allylic substrate in the membrane filter assay. Furthermore, product analyses showed that D97A yielded shorter chain prenyl diphosphates as the main product, while Y103S gave the final product with a C(40) prenyl chain length. These results suggest that some of the conserved residues in region B of component I are involved in the binding of allylic substrate as well as determining the chain length of the enzymatic reaction product.

Alkyl and Aryl Transferases↗
PubMed1999

Preparation of recombinant rat interleukin-5 by baculovirus expression system and analysis of its biological activities.

Rat interleukin-5 (IL-5) cDNA was subcloned from peritoneal cells collected 4 h after intraperitoneal injection of Ascaris suum antigen solution into the immunized rats. Cysteine proteinase-deleted (CPd) rat IL-5 recombinant virus was constructed by inserting rat IL-5 cDNA into CPd virus having a deletion in the cysteine proteinase gene of the silkworm Bombyx mori nuclear polyhedrosis virus. On infection with the CPd rat IL-5 recombinant virus, the silkworm B. mori larvae produced rat IL-5 as a dimeric form in hemolymph. Recombinant rat IL-5 was purified more than 95.5% by anion-exchange chromatography and hydrophobic chromatography. The purified recombinant rat IL-5 promoted the proliferation of T88-M cells in a concentration-dependent manner, and its effect was inhibited by an anti-murine IL-5 neutralizing polyclonal antibody. When bone marrow cells from normal rats were incubated with recombinant rat IL-5 in medium containing methylcellulose, the colony formation by eosinophilic cells was induced. Furthermore, when rat peritoneal eosinophils were incubated with recombinant rat IL-5, the spontaneous decrease in the eosinophil viability was inhibited in time- and concentration-dependent manners. In addition, the recombinant rat IL-5-induced eosinophil survival was inhibited by an anti-murine IL-5 neutralizing polyclonal antibody. These findings suggest that rat IL-5 acts as B-cell growth factor II (BCGF-II), eosinophil differentiation factor (EDF), and eosinophil survival-enhancing factor.

Animals↗