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Biomedical subjects

K Shimizu

Publications and source records attributed to K Shimizu.

At least 613 records · Page 34Linked to original sources
PubMed1997

[The mechanisms of the inhibition of gastric acid secretion induced by intraduodenal amino acids in rats].

We investigated the effect of intraduodenal amino acids (AA) on gastric acid secretion and gastrin release, and possible role of endogenous secretin on this phenomenon in vivo in rats. Intraduodenal administration of mixed AA solution (140 mg/hr, pH6.5) resulted in significant inhibition of gastric acid secretion and gastrin release stimulated by intragastric perfusion of peptone (0.5%). Intravenous infusion of secretin (0.05CU/kg/hr) also inhibited peptone-stimulated gastric acid secretion and gastrin release. Furthermore, the AA-induced suppression of gastric acid secretion was significantly blocked by intravenous injection of rabbit anti-secretin serum. In conclusion, intraduodenal AA inhibit peptone-stimulated gastric acid secretion and gastrin release, and endogenous secretin released by AA is attributed to this suppression. Thus, the result of this study indicates that intestinal AA regulate gastric secretory function mediated by AA-released endogenous secretin in the intestinal phase.

Amino Acids↗
PubMed1997

Decreased pulmonary arterial endothelium-dependent relaxation in heartworm-infected dogs with pulmonary hypertension.

OBJECTIVE: To investigate the contractility of pulmonary arterial smooth muscle and the relation between pulmonary hypertension and endothelium-derived relaxing factor in canine heartworm disease. ANIMALS: 18 noninfected control and 9 heartworm-infected dogs. PROCEDURE: Mean pulmonary arterial blood pressure was measured in vivo, and tension of pulmonary arterial strips was measured by use of the isometric tension method. RESULTS: After phenylephrine (10(-5)M)-induced contraction of the pulmonary vascular smooth muscle, carbamylcholine chloride (CCh, 10(-6)M) caused more relaxation of the vascular smooth muscle of noninfected, dogs than that of heartworm-infected dogs. Furthermore, the degree of CCh-induced relaxation was inversely correlated with mean pulmonary arterial blood pressure in the noninfected and the heartworm-infected dogs. The CCh-induced relaxation was inhibited by pretreatment with NG-nitro-L-arginine methyl ester hydrochloride (10(-5)M), and in reversed dose-dependent manner by L-arginine (10(-4) to 3 x 10(-2)M). Sodium nitroprusside (10(-8) to 10(-5)M) caused a dose-dependent relaxation in all vessels, and there was no significant difference in the relaxation responses in both groups except at 10(-7)M for vessels with intact endothelium from noninfected dogs. CONCLUSION: The depression of endothelium-dependent relaxation is correlated with the pulmonary arterial blood pressure in heartworm-infected dogs, suggesting that the decrease is one of the essential factors for the genesis of pulmonary hypertension in canine filariasis.

Animals↗
PubMed1997

In vitro fertilization of follicular oocytes by frozen-thawed spermatozoa in Japanese monkeys (Macaca fuscata).

We report the cryopreservation of epididymal spermatozoa and in vitro fertilization for Japanese monkeys (Macaca fuscata). Ovarian stimulation of seven monkeys was studied by the administration of equine chorionic gonadotrophin (eCG) and human chorionic gonadotrophin (hCG) during the nonbreeding season, after which oocytes were collected from ovarian follicles. The oocytes were subjected to in vitro fertilization by the frozen-thawed epididymal spermatozoa collected from a male monkey during the nonbreeding season. Before the experiment the epididymides and oocytes were transported about 500 km, during which the epididymides were kept in mineral oil to prevent drying and the oocytes were kept in a maturation medium. This technique of cryopreservation and in vitro fertilization has a wide applicability in nonhuman primate reproduction, including the treatment of infertility and the preservation of wild, nonhuman primates.

Animals↗
PubMed1997

AML1a but not AML1b inhibits erythroid differentiation induced by sodium butyrate and enhances the megakaryocytic differentiation of K562 leukemia cells.

AML1 may play a role in growth and differentiation of cells along erythroid and/or megakaryocytic lineages, because a significant level of the AML1 gene is expressed in these cells. We overexpressed AML1a (without the transcription-activating domain) and AML1b (with the domain) proteins in K562 leukemia cells, which can be induced to differentiate into hemoglobin-producing cells and megakaryocytes. The AML1a-transfected K562 cells had a reduced capacity to differentiate in the presence of sodium n-butyrate but not in the presence of other inducers, such as hemin, 1-beta-D-arabinofuranosylcytosine, and herbimycin A. The AML1 antisense oligodeoxynucleotide but not the sense oligomer recovered its differentiation-inducing capacity in the presence of butyrate. On the other hand, AML1b conferred a similar differentiation-inducing capacity upon K562 cells transfected with vector alone. AML1a expression was associated with enhanced sensitivity to megakaryocytic differentiation induced by phorbol ester. These results provide evidence that AML1 proteins play a role in erythroid and megakaryocytic differentiation.

Antigens, CD↗
PubMed1997

[Helical CT of the breast: detection of intraductal spread and multicentricity of breast cancer].

PURPOSE: This study was performed to evaluate the clinical utility of postcontrast helical CT (HCT) scan for the detection of intraductal spread (DS) and multicentricity of breast cancer. MATERIALS AND METHODS: DS and multicentricity in 84 patients with invasive ductal carcinoma were evaluated by preoperative postcontrast HCT. The HCT protocol of 3-mm section width and 3 mm/sec table speed was used with the patients in a supine position. Scanning started 70sec after beginning the intravenous injection of 90 ml (27 gI) of contrast material at the rate of 1.5 ml/sec. The three-dimensional images were displayed. RESULTS: Eighty-four of 84 main tumors (100%) were shown as enhanced masses by postcontrast HCT. The sensitivity and specificity of HCT for the detection of DS and multicentricity were 60.0% (18/30) and 88.9% (48/54), and 88.9% (16/18) and 90.9% (60/66), respectively. When DS and multicentric lesions were combined, the sensitivity and the specificity were 76.3% (29/38) and 89.1% (41/46), respectively. CONCLUSION: HCT of the breast is effective in detecting DS and multicentric lesions of breast cancer and might be useful in helping surgeons to successfully perform breast-conserving surgery.

Adult↗
PubMed1997

[Interstitial pneumonia in an HTLV-I carrier].

A 31-year-old woman was admitted to our hospital because of dyspnea on exertion. She had had the same symptom a few years earlier. A chest radiograph revealed ground-glass-like shadows on both sides, and the arterial PaO2 was 54 Torr when the patient was breathing room air. We first suspected hypersensitivity pneumonitis, but the dyspnea and hypoxemia did not resolve during treatment in the hospital, and returned home. She felt no obvious changes in symptoms while at home. We found no antibodies to Tricosporon cutaneum in her serum. Computed tomography of the chest revealed diffuse pan-lobular areas of high density. Bronchoalveolar lavage was done and the total cell count was 9.6 X 10(7). About three quarters (73%) of the recovered cells were lymphocytes. Examination of a transbronchial biopsy specimen showed alveolar thickening with infiltration of small mononuclear cells. No granulomas or Massons bodies were seen, and no antibodies specific to collagen-vascular disease were detected. We therefore excluded the diagnosis of hypersensitivity pneumonitis, idiopathic interstitial pneumonia and collagen-associated pneumonitis. There was no evidence of drug-induced pneumonitis. She was seropositive for HTLV-I. We suspected that this was a case of HTLV-1-associated pneumonitis.

Adult↗
PubMed1997

[Usefulness of 3-D dynamic pulmonary xenon-133 SPECT for thoracoscopic lung volume reduction surgery in patients with pulmonary emphysema].

Six patients with pulmonary emphysema scheduled to undergo thoracoscopic lung volume reduction surgery (TLVRS) were evaluated by three-dimensional (3-D) dynamic pulmonary xenon-133 SPECT. Serial 30-second dynamic SPECT data for equilibrium and washout (for 5 min) were acquired using a continuous repetitive rotating acquisition mode with a triple-detector SPECT system. SPECT data were reconstructed to 3-D images with a color, surface-rendering technique, and a 3-D fusion image of the 3-min washout image over the equilibrium image was obtained. Regional ventilation was visually assessed on the fusion 3-D images and quantified by xenon-133 half-washout time (T1/2) and mean transit time (MTT). The 3-D fusion image localized and lateralized the worst diseased sites with xenon-133 retention. Xenon-133 retention, T1/2 and MTT were reduced on these images in five patients with improved pulmonary function tests following TLVRS. However, xenon-133 retention was greater in one with asynchronous diaphragm movement after TLVRS. This modality will assist TLVRS in determining the lung resection target and in evaluating the treatment effect.

Endoscopy↗
PubMed1997

A novel therapeutic approach for rectal varices: a case report of rectal varices treated with double balloon-occluded embolotherapy.

We present a patient with continuous melena, diagnosed as rectal varices bleeding. She had a history of esophageal varices, which was treated by endoscopic ligation therapy. Eight years after the treatment of esophageal varices, the continuous melena began. Colonoscopic examination showed that the melena was caused by rectal varices, which were so severe that they could not be treated by either endoscopic sclerotherapy or surgical devascularization. Taking into considering the overall risk of treating rectal varices, we chose the approach of double balloon-occluded embolotherapy (DBOE) with 5% ethanolamine oleate with iopamodol as a liquid embolic material. DBOE is one of the interventional radiology techniques (Morita et al., Acta Hepatol Jpn 1994;35:109-120), but in this case was a completely new and novel clinical procedure for rectal varices. After the DBOE therapy, the condition of rectal varices was markedly improved. Thus, DBOE might be a new tool for treating inoperable rectal varices.

Aged↗
PubMed1997

Genetic relationships of Asians and Northern Europeans, revealed by Y-chromosomal DNA analysis.

We have identified a new T-->C transition on the human Y chromosome. C-allele chromosomes have been found only in a subset of the populations from Asia and northern Europe and reach their highest frequencies in Yakut, Buryats, and Finns. Examination of the microsatellite haplotypes of the C-allele chromosomes suggests that the mutation occurred recently in Asia. The Y chromosome thus provides both information about population relationships in Asia and evidence for a substantial paternal genetic contribution of Asians to northern European populations such as the Finns.

Animals↗
PubMed1997

5-Hydroxytryptamine1B and alpha 2 adrenaline receptors in the brain of rats prenatally treated with methylazoxymethanol.

Methylazoxymethanol (MAM)-induced cerebral hypoplasia resulted in a significant increase in concentrations of 5-hydroxytryptamine (5-HT, serotonin) and norepinephrine in the frontal cortex, suggesting that these monoaminergic neurons were compressed due to smaller brain volumes. The serotonergic and noradrenergic presynaptic autoreceptors in rat brain are thought to be 5-HT1B receptors and alpha 2-adrenoceptors, respectively. If so, prenatal MAM treatment should increase the density of 5-HT1B and adrenaline alpha 2 receptors in the brain via the compression of noradrenergic and serotonergic axon terminals in the brains of rats with MAM-induced microencephaly. However, neither the densities nor the affinities of 5-HT1B and adrenaline alpha 2 receptors were changed in the MAM rats, suggesting that these presynaptic autoreceptors comprise only a small percentage of the total receptor population. Most 5-HT1B and adrenaline alpha 2 receptors were localized post-synaptically.

Alkylating Agents↗
PubMed1997

Effects of vestibular rehabilitation on postural control.

We evaluated the effects of vestibular rehabilitation on postural instability in 2 patients with unilateral and bilateral reduced vestibular function. Another patient with unilateral vestibular disorder was treated with drugs without vestibular rehabilitation. The outcome of postural control in these 3 patients was measured using an EquiTest. With this apparatus, improvement of postural stability and change of postural strategy were measured under the condition eyes closed and platform movement was dependent on the subject's anterior-posterior sway. The observations suggest that the vestibular rehabilitation had a positive effect not only on postural stability but also on postural strategy.

Adult↗
PubMed1997

[Quantitative evaluation of pulmonary perfusion volume using 99mTc-MAA SPECT: a comparison of COPD patients and healthy volunteers].

99mTc-MAA pulmonary perfusion single-photon emission computed tomography was performed on 18 patients with chronic obstructive pulmonary disease (COPD) and 41 healthy male volunteers. We quantified the extent of pulmonary perfusion with the Application Visualization System. We measured the pulmonary perfusion volume (PV) at 8 threshold levels encompassing 10 percentage points each from 21-100%. We also calculated the ratio of perfusion volume to total perfusion volume (TPV) at each threshold. Pulmonary perfusion volume in healthy volunteers remained relatively constant at levels of 31-70% and decreased gradually at levels of 71-100%. There was no significant difference in perfusion volume between smokers and non-smokers. Perfusion volume in COPD patients gradually decreased at levels of 31-60% and markedly decreased at levels greater than 60%. Perfusion volume differed significantly between COPD patients and healthy volunteers at levels of 41-100%. The mean PV/TPV value of COPD patients was significantly higher than that of healthy volunteers at levels of 21-40% and significantly lower than that of healthy volunteers at levels of more than 50%. This finding demonstrates that lung volume at high levels of pulmonary perfusion is decreased in COPD patients. The pulmonary perfusion volume at levels of more than 60% is an efficient means of distinguishing COPD patients from healthy subjects.

Adult↗