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Biomedical subjects

T Shibata

Publications and source records attributed to T Shibata.

At least 577 records · Page 32Linked to original sources
PubMed1993

Role of ATP-sensitive K+ channel on ECG ST segment elevation during a bout of myocardial ischemia. A study on epicardial mapping in dogs.

BACKGROUND: ATP-sensitive K+ channels are activated when the myocardium becomes ischemic. However, the role of the ATP-sensitive K+ current in the emergence of ECG ST changes during ischemia remained unclarified. METHODS AND RESULTS: The left anterior descending coronary artery (LAD) was cannulated and perfused with arterial blood from the carotid artery through a bypass tube in 8 anesthetized, open-chest dogs. An array of 60 unipolar electrodes mounted on a sock was used to record epicardial electrograms of the whole heart. Pinacidil (10 micrograms.kg-1 x min-1), an ATP-sensitive K+ channel opener, was infused into the bypass tube for 2 minutes, and the electrograms were recorded before and after the infusion. The elevation of the ST segment and the increase of QRST area were observed spatially over the LAD-perfused region. At the electrode showing the largest ST segment elevation, the activation recovery interval, an index of action potential duration, was shortened from 202 +/- 9 to 111 +/- 18 milliseconds (P < .001). These electrographic changes were similar to those noted in 2-minute coronary occlusion (n = 8). The extent of ST segment elevation during coronary occlusion was attenuated after the intravenous pretreatment with glibenclamide (0.3 mg/kg), a blocker of the KATP channel (n = 5). CONCLUSIONS: The findings of this study suggest that the activation of ATP-sensitive K+ channels during a bout of acute myocardial ischemia plays an important role in the emergence of ECG ST elevation.

Action Potentials↗
PubMed1993

Localization of basic fibroblast growth factor (bFGF)-like immunoreactivity in neural circuits innervating the gastrocnemius muscle, with reference to the direction of bFGF transport.

An antiserum against basic fibroblast growth factor (bFGF), characterized by immunoblot, was firstly used to immunolocalize bFGF-like materials in dorsal root ganglion (DRG) neurons, spinal motoneurons and their processes innervating the gastrocnemius muscle, and then secondly to determine the direction of bFGF transport in the processes by nerve ligation or nerve section experiments. Light and electron-microscopic immunohistochemistry revealed that significant numbers of DRG neurons (mainly of the large type), spinal motoneurons and their processes supplying the muscle are immunoreactive for bFGF, and that the bFGF neurons have diffuse immunoreaction deposits over the entire cytoplasmic areas except for the Golgi complex, mitochondria and microfilaments. Nerve terminals and glial processes with bFGF were rarely seen in contact with or in close apposition to the immunopositive neurons. At sixteen hours, 3 days and 7 days after unilateral ligation or transection of the sciatic nerve, bFGF fibers accumulated in a time-dependent way in the proximal but not in the distal stump; nerve transection caused a more intense accumulation of bFGF-immunoreactive fibers than did nerve ligation. These findings suggest that bFGF in large DRG neurons and motoneurons is transported anterogradely into the peripheral tissue, possibly without being incorporated into secretory granules or synaptic vesicles. They raise the possibility that bFGF within the transected nerve fibers is more actively conveyed during regeneration than in the ligated nerve fibers.

Animals↗
PubMed1993

Inhibitory effect of xian-qing-long-tan extract on degranulation and histamine release from rat mast cells.

Xian-Qing-Long-Tang (XQLT), a Chinese medicine, is useful for treating allergic diseases. To demonstrate the anti-allergic effect of this drug we examined its effect on degranulation and histamine release from rat mast cells induced by antigen and compound 48/80. The effect on 48 h homologous passive cutaneous anaphylaxis (PCA) in rats was also studied. In the IgE antigen-antibody reaction using DNP-As, XQLT inhibited histamine release from rat mast cells, in vitro; it also inhibited 48 h rat homologous PCA reaction, in vivo. These results suggest that XQLT inhibits type 1 allergic reaction, and has effectiveness for allergic disease.

Animals↗
PubMed1993

Selective accumulation and tumoricidal effect of cisplatin suspended in viscous ethyl oleate on hepatic cancers in animals after intraarterial infusion.

The selective accumulation and tumoricidal effects of cisplatin after intra-arterial infusion suspended in viscous ethyl oleate (VEO) on hepatic cancers of AH 272 tumor-bearing rats and VX-2 tumor-bearing rabbits were compared with those of cisplatin suspensions in ethyl oleate (EO) and Lipiodol Ultra Fluide (LP). The viscosities of VEO, EO and LP were 120, 4, and 21 centipoise (cp) respectively. Complete in vitro release of cisplatin from EO and LP occurred within 24 h, whereas only about 25% of cisplatin was released from VEO over the same period. When EO or VEO containing 3H-oleic acid were infused into the hepatic artery of rat liver inoculated with AH 272 tumor cells, radioactivity in the tumor site was higher than that in normal liver. In the case of cisplatin, concentration ratios after the infusion of EO and VEO were almost the same as those of oily carriers. Similar results were obtained in rabbit liver inoculated with VX-2 tumor cells. Cisplatin concentration in the tumor site seven days after intra-arterial infusion of VEO suspension was 5- and 1.7-fold higher, respectively, than that after EO and LP suspensions. The tumoricidal effect of cisplatin in VEO suspension on AH 272 tumor-bearing rats was higher than that after cisplatin solution and EO and LP suspensions, while VX-2 tumor growth was inhibited by the infusion of all cisplatin-containing oily carriers. VEO suspension thus appears very promising in intra-arterial infusion therapy.

Animals↗
PubMed1993

Atlas hypoplasia as a cause of high cervical myelopathy. Case report.

A high cervical myelopathy due to atlas hypoplasia is described in a 56-year-old man; the condition caused marked segmental compression of the spinal cord. A remarkable neurological recovery followed decompressive laminectomy of the atlas and adjacent regions. The authors discuss the embryology and etiology of this anomaly.

Cervical Atlas↗
PubMed1993

L-gulono-gamma-lactone oxidase is not induced in rats by xenobiotics stimulating L-ascorbic acid biosynthesis.

L-Ascorbic acid (AsA) is synthesized from D-glucose in rats; the terminal step of this synthetic pathway is catalyzed by L-gulono-gamma-lactone oxidase (GLO). In this study, we examined the effects of phenobarbital (PB) and 3-methylcholanthrene (MC), both of which are known to stimulate AsA biosynthesis in rats, on the hepatic levels of GLO activity, GLO mRNA, and AsA. Firstly, the existence of GLO mRNA was examined in the liver, kidney, lung, small intestine, spleen, testis, and prostate from a male rat; and GLO mRNA was found to be present only in the liver, in which GLO activity was also detected. The intraperitoneal injection with PB (100 mg/day/kg body weight, once a day for 2 days) or MC (20 mg/day/kg body weight, once) significantly elevated the hepatic level of AsA and the urinary excretion of AsA in rats (5-week-old males). The hepatic levels of cytochrome P-450IIB1 mRNA and cytochrome P-450IIB2 mRNA and those of cytochrome P-450IA1 mRNA and cytochrome P-450IA2 mRNA were also elevated in the rats treated with PB and MC, respectively, indicating a normal response of these animals to these compounds. However, the level of GLO mRNA and the activity of GLO in the liver tended to be slightly decreased by the administration of PB or MC, though the differences were not significant. Thus it is clear that the treatment with PB or MC stimulates the biosynthesis of AsA by increasing the activity of some enzyme(s) participating in the synthesis prior to GLO.

Animals↗
PubMed1993

Osteosarcoma with epithelioid features. An immunohistochemical study.

We report a case of osteosarcoma with coexpression of epithelial and mesenchymal markers immunohistochemically of the second lumbar vertebra in a 49-year-old man. Histologically, the tumor largely showed typical patterns of osteosarcoma with lacelike osteoid deposition and chondroblastic and fibroblastic areas. Immunoreactivity for osteocalcin (human bone gamma-carboxyglutamic acid-containing protein) was demonstrated in most of these tumor cells. Both primary and recurrent tumors contained areas that were composed of epithelioid cells with an alveolar pattern and a trabecular arrangement that resembled carcinoma. Some of the epithelioid cells gave positive reactions for cytokeratin and epithelial membrane antigen. On extensive examination, no other site of malignancy was detected. There have been a few reports of osteosarcomas with epithelioid cells, but to our knowledge, the immunohistochemical properties of this type of tumor have not been reported previously. This is an unusual case of osteosarcoma with epithelioid features.

Humans↗
PubMed1993

[Studies on the preparation of sample solution for determination of nicotinic acid and nicotinamide in foods by high performance liquid chromatography].

A method for preparation of sample solution for determination of nicotinic acid (NA) and nicotinamide (NAA) in foods by high performance liquid chromatography has been studied. NA and NAA were simultaneously extracted from foods with methanol, then the extracts were cleaned up by use of a Sep-Pak tC18 cartridge. NA and NAA in each sample solution were determined by high performance liquid chromatography. Recoveries of NA and NAA from various foods spiked at levels of 25 and 250 micrograms/g were not less than 70%.

Chromatography, High Pressure Liquid↗
PubMed1993

[Estimated production by the official inspection of coal-tar dyes (including dye aluminum lakes) in 1992].

The number of official inspection of coal-tar dyes and their lakes from April in 1992 till March in 1993 were 711 in total. The quantity which passed inspection amounted to 201 ton in Japan. The production of color in each month was summarised in Table 1, and by each producing company in Table 2. The food coal-tar dye produced in the largest quantity was Food Yellow No. 4, occupying 40.7% during this period.

Chemical Industry↗
PubMed1993

Clinical applications and basic studies of laser in dentistry and oral surgery.

In our clinical use of lasers, mainly CO2 laser for oral surgery, we found that the laser had many advantages over an electrome and the laser improved the local control rate for malignant tumors. Low-power laser has been used to treat hypersensitive dentin, to relieve pain caused by neurotic disease around mouth, and to promote the healing of those diseases. The results obtained from the clinical applications showed that irradiation of the hypersensitive dentin with low-power laser was significantly effective in desensitization. An in vitro study showed no effects of diode or He-Ne laser irradiation on the growth of cells, but showed changes in the initial cell adhesion rate. He-Ne laser irradiation to the wound in the skin of hamsters caused to change the activities of the types I and III collagenase. This fact suggest that laser irradiation acted to promote the healing of wound.

Animals↗
PubMed1993

Case-control study of senile cataract in Japan: a preliminary report.

A hospital-based case-control study of senile cataract was conducted in Japan from 1988 to 1990. Two hundred and twelve patients with senile cataract and 212 control subjects with the same age-sex distribution were interviewed and given an ophthalmological examination. Both groups were randomly selected outpatients from 9 hospitals. Associations between senile cataract and four groups of variables, factors regarded as risks, life style habits, general aging indices or other factors were analyzed, and the data was subjected to statistical analysis. An increased risk of cataract was found in males who were presently spending 7 hours or more outside daily (Odds ratio = 5.07) and in females with 4 or fewer remaining teeth (Odds ratio = 2.03). The findings from this study suggest that there may be a sex-related host sensitivity or life style which is predisposing to the development of senile cataract.

Adult↗
PubMed1993

[The effects of sevoflurane anesthesia with hypothermia on ischemic brain cellular respiration].

We examined the effects of sevoflurane anesthesia with hypothermia on ischemic brain cellular respiration using Wistar strain rats. Ischemia was induced by decapitation. L/P in brain increased during no anesthesia-normothermia-ischemia (1), then gradually, but not fully recovered during 2.5% sevoflurane anesthesia-normothermia-ischemia (2) and during 2.5% sevoflurane anesthesia-hypothermia-ischemia (3). Energy charge decreased during (1) and slight recovery was observed during (3). Respiratory control ratio in brain mitochondria decreased during (1) and recovery during (2) and (3) was slight. No recovery was observed in ADP/O. These findings indicate that during sevoflurane anesthesia with hypothermia, ischemic brain energy metabolism has an effect not on the mitochondrial energy producing processes but on the consuming system.

Anesthesia, Inhalation↗
PubMed1993

[Prevalence and distribution of Helicobacter pylori in the stomach of patients by upper gastrointestinal endoscopy].

The prevalence of H. pylori colonization in the antrum and body was examined in patients with gastritis, duodenal ulcer (DU) and gastric ulcer (GU). The total prevalence was 63.5%, 90.0% and 85.5%, respectively. In patients with gastritis and DU, the frequency was similar at both sites, while in GU patients H. pylori positivity was increased markedly in the body compared with the antrum. Furthermore, in patients with antral and angular ulcers, biopsy studies from 8 different sites showed that the H. pylori density score was significantly higher at the ulcer sites than at the non-ulcer sites. H. pylori infection is strongly implicated in the pathogenesis of gastritis and peptic ulceration.

Duodenal Ulcer↗
PubMed1993

A case report of allergic granulomatosis and angiitis (Churg-Strauss syndrome) with a review of the literature.

We report the case of a 67-year-old man with allergic granulomatosis and angiitis (AGA; Churg-Strauss syndrome) who developed nephrotic syndrome during his clinical course and demonstrated membranous nephropathy on renal necropsy by electron microscopy. Following the development of symptoms of bronchial asthma accompanied by eosinophilia and mononeuritis multiplex, transbronchial lung biopsy confirmed a diagnosis of AGA. The patient died of pneumonia and disseminated intravascular coagulopathy, but necropsy revealed severe tubulo-interstitial damage with neutrophilic infiltration and, in half of the glomeruli, mesangial proliferation with subepithelial dense deposits. This paper thus describes a rare case of AGA complicated by a secondary type of stage I membranous nephropathy.

Aged↗
PubMed1993

[Pathologic changes at the coronary artery-bypass graft anastomosis--an immunocytochemical study].

We have performed immunocytochemical investigations on proliferative tissues observed in anastomotic sites of the saphenous vein aortocoronary bypass grafts to the coronary arteries. Nine anastomotic sites were obtained from 5 necropsy patients who had died after bypass grafting. Interval between the operation and death in these patients varied from 5 days to 9 months. The anastomotic sites were fixed in methanol-Carnoy's fixative, and embedded in paraffin. Six monoclonal antibodies specific for muscle cell actin (HHF35), smooth muscle cell actin (CGA7), vimentin, desmin, macrophages (HAM56) and endothelial cells were used for the immunocytochemical study. Of the 9 anastomotic sites, 4 were totally occluded, while the remaining 5 were patent. The occluded sites were characterized by a presence of fresh or organized thrombus. Immunocytochemically, the latter was composed of macrophages, smooth muscle cells and neovascularization. In contrast, a patent site at 5 days after grafting showed an early stage of intimal proliferation composed of macrophages and spindle-shaped cells. Two patent sites at 33 days after grafting revealed a distinct intimal thickening consisting almost entirely of smooth muscle cells. At this stage, smooth muscle cells at a deeper intima were stained positive with both HHF35 and CGA7, whereas the cells at the luminal site were stained positive with HHF35 but negative with CGA7. In older lesion at 9 months after grafting, almost all smooth muscle cells within intimal thickening showed positive with HHF35 and CGA7. Moreover, these smooth muscle cells were stained positive with vimentin but were negative with desmin, irrespective of the lesion's age.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗