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Biomedical subjects

M Yoshioka

Publications and source records attributed to M Yoshioka.

At least 235 records · Page 13Linked to original sources
PubMed1995

Oxygen transport and hemodynamics during retrograde whole-body perfusion.

The changes in oxygen transport and hemodynamics during retrograde whole-body extracorporeal perfusion (retro-ECC) were studied in six mongrel dogs. Oxygen consumption during retro-ECC, in which the blood flow rate was set at 25% and 50% of the flow during antegrade extracorporeal perfusion (ante-ECC), respectively, was relatively high compared with that during ante-ECC. These changes were caused by an increase in the oxygen extraction ratio to 71.5% +/- 8.2% and 51.2% +/- 12.4% during retro-ECC/25% and retro-ECC/50%, respectively. Thus, tissue perfusion was apparently well maintained by retrograde perfusion on the basis of the oxygen transport data. However, central venous pressure increased markedly to 29.5 +/- 11.6 mmHg and 56.2 +/- 24.5 mmHg during retro-ECC/25% and retro-ECC/50%, respectively, because of massive venous congestion caused by insufficient arterial return of perfused blood. The great venous compliance and increased systemic vascular resistance were the main causes of circulatory failure during retro-ECC. The risk of serious complications owing to the venous congestion must be considered during retrograde perfusion, especially during the clinical application of retrograde cerebral perfusion.

Animals↗
PubMed1995

Dichotic listening in patients with partial section of the corpus callosum.

Patients with a complete section of the corpus callosum have been observed to exhibit strong left-ear suppression when different speech stimuli are presented to both ears simultaneously (so-called dichotic listening). Data concerning the locus of corpus callosum damage that causes strong left-ear suppression remains scanty. In the present investigation, a consonant-vowel syllable dichotic listening test was given to five right-handed patients with partial sections of the corpus callosum, which were located using MRI and accurately defined measurement procedures. The following two measurement methods were used: (i) the genu-splenium (G-S) method, in which a lesion was localized in the anteroposterior dimension relative to the total length of the corpus callosum, defined as the distance between the most anterior point of the genu to the most posterior point of the splenium; and (ii) the rostrum-splenium (R-S) method, which takes into account the curvature of the corpus callosum, and in which a lesion was localized relative to the total length of the corpus callosum, defined as the length of the curved line from the tip of the rostrum to the end of the splenium. Results were compared with scores from 50 normal control subjects. Strong left-ear suppression was observed in two patients, who had surgical sections of the posterior 15.5-18.5% of the corpus callosum as measured with the G-S method, or the posterior 20-24% of the corpus callosum as measured with the R-S method. The suppression phenomenon persisted for more than 10 years post-surgery. On the other hand, the remaining three patients, who had lesions anterior to the posterior 17-28% of the corpus callosum as measured with the G-S method or 20-33% as measured with the R-S method exhibited no left-ear extinction. Despite the common assumption that damage to the posterior part of the trunk of the corpus callosum causes strong left-ear suppression, the results from the G-S method indicated that damage to the splenium defined as the posterior one-fifth of the segment between the anterior-most and posterior-most points of the corpus callosum, cause strong left-ear suppression. By the R-S method, results showed that damage to the splenium (the posterior one-fifth of the curvature of the corpus callosum) and possibly the part extending to the most posterior part of the trunk (the posterior one-quarter of the curvature) causes strong left-ear suppression.

Adult↗
PubMed1995

Animal models of vascular dementia with emphasis on stroke-prone spontaneously hypertensive rats.

1. Two experimental models designed to reflect different aspects of vascular dementia (rats with cerebrovascular occlusion and rats with cerebral embolization) and stroke-prone spontaneously hypertensive rats (SHRSP) have been evaluated. The focus was on SHRSP as a model for vascular dementia. 2. Neuropathological data revealed that the cerebrovascular disorder in SHRSP was associated with lesions in their brains similar to those seen in typical human cases of multiple cerebral infarction. 3. SHRSP that died from cerebral infarction exhibited behavioural changes, including increased activity and disrupted circadian rhythms, which might correspond to the state of delirium observed in patients with dementia. 4. SHRSP displayed cognitive impairments in a step-through passive avoidance task. 5. When compared to age-matched Wistar Kyoto (WKY) rats, both conscious and anaesthetized SHRSP had significantly decreased cerebral spinal fluid (CSF) levels of acetylcholine (ACh). 6. These findings suggest that the SHRSP might serve as a suitable animal model for vascular dementia in humans caused by cerebrovascular lesions.

Animals↗
PubMed1995

Immunocytochemical detection of tumor necrosis factor-alpha in infiltrating tumor cells in the cerebrospinal fluid from five patients with leptomeningeal carcinomatosis.

We studied the immunoreactivity for tumor necrosis factor-alpha (TNF-alpha) in cerebrospinal fluid (CSF) cell smears from five patients with leptomeningeal carcinomatosis (LC). Immunostained TNF-alpha-positive tumor cells had brownish deposits in the cytoplasm, but no deposits were observed in the nucleus. The intensity of the TNF-alpha staining was greater in these tumor cells than in macrophages from patients with inflammatory diseases. Approximately 27-72% of the tumor cells were found to be TNF-alpha immunoreactive in all five samples from the patient with LC. These results suggest that the large amount of TNF-alpha produced by infiltrating tumor cells may play an important role in the development of the tumor.

Adenocarcinoma↗
PubMed1995

[Study of pathogenicity of various serovars of Enterococcus faecalis].

Using a mouse experimental UTI (urinary tract infection) model, a study was conducted to find the pathogenicity of various serovars of E. faecalis. On the basis of studies employing serovar-specific factor sera prepared with E. faecalis type strains, serovar 2, 3, 4 and 10 strains showed a high incidence of involvement in pyelonephritis: 90.3%, 85.7%, 85% and 73.3%. Serovar 1, 6 and 7 strains each showed a 63.6% incidence of involvement in pyelonephritis, indicating that they have a moderate pathogenicity. The pathogenicity of the other serovar strains was not very strong, with a low incidence of 40-59.1%. These results were thus in good agreement with the findings of the study using the mouse experimental UTI model infected with clinical isolates. Serotyping was performed of E. faecalis clinical isolates obtained from patients with pyelonephritis or urosepsis. Serovars 2 and 4 comprised 75.1% of these isolates. It was surmised that E. faecalis serovars 2 and 4 tend to have strong pathogenicity. Thus, there were quite a few differences in pathogenicity of E. faecalis according to each kind of serovar.

Animals↗
PubMed1995

[Study of distribution of serovars of Enterococcus faecalis clinical isolates].

Serotyping was conducted of E. faecalis strains isolated from various clinical specimens, and the distribution of the serovars was investigated. To date, 21 serovars of E. faecalis have been identified. The most common serovars in Japanese 770 strains were types 2 (30.6%), 7 (13.9%), 1 (12.2%) and 4 (6.9%), and these four serovars accounted for 63.6% of the total strains. The most common serovars in USA 200 strains were types 1 (22.5%), 4 (14.5%) and 2 (14.0%). The most common serovars in UK 65 strains were types 2 (24.6%), 4 (13.8%) and 9 (7.7%). The distribution of E. faecalis serovars differ as a function of the country of origin. Next, serological classification was performed for E. faecalis strains isolated from various Japanese clinical specimens. For the strains obtained from the urine, the most common serovars were types 2 (32.7%) and 7 (14.6%). Similarly, the most common serovars of the strains isolated from the various other clinical specimens were as follows: types 7 (35.0%) and 2 (15.0%) from pus; types 7 (44.4%) and 2 (33.3%) from sputum; types 2 (22.3%) and 1 (13.1%) from blood; and types 2 (34.9%) and 1 (27.9%) from the vaginal smear. It had no definite pattern for the distribution of serovars. The distribution of serovars varied in accordance with isolated years. Accordingly, the data obtained in these studies revealed that the distributions of E. faecalis serovars differ as a function of the geographical area of origin, the clinical specimen of origin and the year of origin. This approach is useful for serological classification of E. faecalis strains, and it is thought that it will be useful for epidemiological studies of this bacterium.

Enterococcus faecalis↗
PubMed1995

[Pulmonary and pulmonary-related reflexes mediated by serotonin receptors in the peripheral nervous system].

It is known that serotonin is widely distributed in the body; its receptors are located in various tissues and organs. It has been reported that serotonin receptors without apparent synaptic structure exist in the peripheral nervous system. These serotonin receptors might be the target of circulatory serotonin. In particular, serotonin has a potent depolarizing action on vagal afferent nerves. This stimulation causes various autonomic reflexes, so-called von Bezold-Jarisch reflex, that consist of bradycardia, hypotension and apnea. The peripheral 5-HT3-receptor subtype seems to be responsible for the initiation of these reflexes. The physiological and pathophysiological significance of these serotonin-induced modulations have not, however, been established. The present study was designed to examine the effects of exogenous serotonin on the chemosensitive afferent nerves including carotid sinus nerves, cervical vagus nerve, and efferent motor nerves, such as phrenic nerves and pharyngeal nerves. Because little is known about the involvement of the serotonergic system in the pulmonary reflex and pulmonary-related reflexes (swallowing or vomiting), the distribution of the motor component of these nerves within the brain stem of the rat was also determined.

Animals↗
PubMed1995

Primary hyperparathyroidism associated with multiple myeloma.

A 73-year-old woman was diagnosed as primary hyperparathyroidism. Hypercalcemia recurred after parathyroidectomy, though serum calcium concentration temporarily resumed to normal. Hypercalcemia was eventually shown to be due to multiple myeloma. In spite of the frequent association of hypercalcemia with malignant disease and the relative frequency of primary hyperparathyroidism as a cause of hypercalcemia, primary hyperparathyroidism accompanied by multiple myeloma has been considered in only a limited number of reports. Here, the cases in the literature are reviewed and discussed.

Adenoma↗
PubMed1995

Effects of red-pepper diet on the energy metabolism in men.

We investigated the effects of dietary red pepper on the energy metabolism in male subjects. In the first experiment, after having a standardized dinner on the previous evening, the subjects consumed a breakfast (650 kcal) either with or without 10 g of red pepper. For 150 min after the meal, they took a rest and their expired gas was collected. During the initial 30 min after the meal, the energy expenditure tended to be higher in the red-pepper diet period than in the control diet period. For the remaining 120 min, no difference in the energy expenditure was found between the red-pepper diet period and the control diet period. However the carbohydrate oxidation was significantly higher in the red-pepper diet period than in the control diet period while the lipid oxidation was lower in the red-pepper diet period than in the control diet period for 150 min after the meal. In the second experiment, the subjects consumed a breakfast with 10 g of red pepper after an oral administration of propranolol or a placebo. The propranolol abolished the increase in energy expenditure during the initial 30 min due to the meal containing red pepper. For the remaining 120 min, no difference in energy expenditure was found between the propranolol period and the placebo period. These results suggest than an increase in the energy expenditure after the meal containing red pepper appeared only immediately after the meal ingestion and a red-pepper diet increases the carbohydrate oxidation without increasing total energy expenditure for 150 min after the meal. And an increase in the energy expenditure immediately after the meal containing red pepper is considered to be caused by beta-adrenergic stimulation.

Adult↗
PubMed1995

[A technique for removal of entrapped intra-aortic balloon catheter through the left axillary artery].

A case of intra-aortic balloon pumping (IABP) entrapment in which the ruptured catheter could be removed through the left axillary artery was reported. A 68-year-old man was admitted with persistent chest pain, and because of his poor cardiac condition, an IAB catheter was inserted by the Seldinger technique. During attempted extraction of the IAB catheter resistance was encountered and it turned out to be entrapped. Then a guide-wire was passed through the IAB lumen to the left axillary artery, the artery was exposed, and the tip of the guide-wire and IAB catheter were led to the arteriotomy site. After the balloon was dissected, the IAB catheter could be removed through the axillary artery. Finally, left femoro-left branchial artery bypass was performed with e-PTFE graft because of the arterial injury and ischemia of the involved arm. The patient recovered from this episode.

Aged↗
PubMed1995

In vivo angioscopic detection of the damaged endothelium on the atheromatous plaque: application with vital staining by methylene blue.

We attempted to detect the lesion of the damaged endothelium on the atherosclerotic plaque in vivo with dye and angioscope. The plaques were induced on the aortae of rabbits by the continuous mechanical injury with the insertion of the polyethylene tube and feeding with 2% cholesterol-added diet. We observed the some plaques could be stained with 5 x 10(-2) mol/L methylene blue by angioscope. Control aorta, without any stimulations on the aorta, could not be stained. One month after injury and cholesterol feeding the plaques were stained. In such plaques, the lack of the endothelium and the existence of the lipid-containing cell in the intima was observed. However, the plaques of the aorta 6 months after finishing these procedures could not be stained. In these plaques, the morphological characteristics known as the regression of the atheromatous plaque, ie, the regeneration of the endothelium, the thick collagen layer on the plaque and the massive calcification of the plaque were observed. The results obtained were as follows. (1) The atheromatous lesion with the damaged endothelium could be detected in vivo by our vital staining method. (2) The atheromatous plaques stained in vivo are the lesion with complication and enhanced permeability. (3) The slightly stained plaques indicate the lesions with regression and lost high permeability. (4) Our method would be able to add important information on the atheroscrelotic lesions in the clinical situations than that now we perform.

Angioscopy↗
PubMed1995

[The accuracy of computed tomography and magnetic resonance imaging in evaluating the extent of endometrial carcinoma].

The present study was designed to determine the accuracy of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) in evaluating the extent of the tumor in 36 patients with endometrial carcinoma. The CT and MRI findings were compared with the microscopic pathologic characteristics in all cases. Linear regression analysis for measurements of residual normal myometrium revealed significant positive correlations (p < 0.001) between MRI (r = 0.861) and CT (r = 0.826) findings and pathologic evaluation. Thirty-six patients were divided into two groups according to our previous CT and MRI criteria: the superficial myometrial invasion group and advanced tumor group. In MRI findings, higher incidences of deep (> or = 1/2) myometrial invasion (p < 0.001), vessel permeation (p < 0.05) and cervical involvement (p < 0.05) were observed in the advanced group. In CT findings, deep myometrial invasion (p < 0.001) was observed in the advanced group. The incidence of extrauterine extension of the tumor did not differ significantly between CT and MRI findings. The accuracy figures for cervical involvement evaluated by CT and MRI were 83% and 86%, respectively. In four of 6 patients, in whom an intact Junctional zone (j-zone) was detected by MRI, the tumor was localized in the endometrium. The remaining 2 patients had only superficial myometrial invasion histologically. In all 16 patients, in whom the j-zone was interrupted in MRI findings, myometrial invasion was confirmed pathologically.(ABSTRACT TRUNCATED AT 250 WORDS)

Endometrial Neoplasms↗
PubMed1995

Modulation of norepinephrine release by serotonergic receptors in the rat hippocampus as measured by in vivo microdialysis.

The functional modulation of norepinephrine (NE) release by serotonergic receptors in the hippocampus of freely moving rats was studied by use of in vivo microdialysis. To stimulate NE release from the nerve terminals, a high concentration of potassium (K+, 120 mM) was added through the perfusion system. The K(+)-evoked NE release was inhibited in a concentration-dependent manner when serotonin (5-HT, 0.01-10 microM) was coperfused with K+. A selective 5-HT3 receptor agonist, 2-methyl-5-HT, mimicked the 5-HT response at a concentration of 0.01 to 10 microM. The 5-HT-induced (1 microM) inhibition of NE release was blocked by pretreatment with ondansetron (1 and 10 microM), a 5-HT3 receptor antagonist. On the other hand, K(+)-evoked NE release was also reduced by coperfusion with the 5-HT reuptake inhibitor, fluoxetine (10 microM), which caused increases in the dialysate 5-HT concentration. The fluoxetine-induced (10 microM) decreases in the K(+)-evoked NE release were prevented by serotonergic denervation caused by pretreatment with 5,7-dihydroxytryptamine (200 micrograms/rat i.c.v.). These results indicate that the inhibition on NE release by fluoxetine was due to increased synaptic concentrations of endogenous 5-HT. The fluoxetine-induced inhibitory effect was furthermore abolished by pretreatment with ondansetron (1 and 10 microM). These findings indicate the possibility that both exogenous and endogenous 5-HT inhibit NE release occurs from the rat hippocampus by 5-HT3 receptors. Thus, the present study suggests that the functional modulation of NE release by 5-HT3 receptors exists in vivo.

Animals↗
PubMed1995

Chemical modulation of 5-HT3 and 5-HT4 receptors affects the release of 5-hydroxytryptamine from the ferret and rat intestine.

In species which vomit, elevated intestinal serotonin (5-hydroxytryptamine, 5-HT) may stimulate abdominal vagal afferent fibers, which in turn evoke the vomiting reflex. The release of 5-HT from intestinal enterochromaffin (EC) cells is regulated by polymodal mechanisms. The object of this study was to evaluate the involvement of 5-HT autoreceptors in the regulation of 5-HT release from the small intestine. Functional studies were carried out using 5-HT3 receptor agonist and antagonists, and 5-HT4 receptor agonist. Ferret and rat ileal tissue were isolated and 5-HT released into the bathing solution was determined using HPLC with an electrochemical detector (ECD). We previously reported that cisplatin produced a significant increase in cumulative 5-HT release and that ondansetron, a selective 5-HT3 receptor antagonist, did not alter the 5-HT release from the ferret ileum. In this study, a selective 5-HT3 agonist, 2-methyl-5-HT, induced a dose-dependent increase of 5-HT from the rat ileum. This release of 5-HT was significantly reduced by granisetron, a selective 5-HT3 receptor antagonist. Furthermore, a selective 5-HT4 receptor agonist, 5-methoxytryptamine induced a concentration-dependent increase of 5-HT in the rat ileum. These results suggest that both 5-HT3 and 5-HT4 receptors may be involved in intestinal 5-HT release.

5-Methoxytryptamine↗
PubMed1994

Clinical spectrum and genetic studies of Fukuyama congenital muscular dystrophy.

The association of congenital muscular dystrophy (CMD) with type II lissencephaly and ocular anomalies is found in Fukuyama CMD (FCMD), the Walker-Warburg syndrome (WWS), and muscle-eye-brain disease (MEBD). The classification of these disorders remains controversial. Between 1972 and 1992, we performed clinical and genetic studies in 41 families of FCMD, which is particularly frequent in Japan. Nine families (22%) had multiple affected children ("familial" FCMD). The other 32 families had only one affected child ("sporadic" FCMD). Parental consanguinity was documented in 5 sporadic FCMD families and in none of the familial cases. In total, 48 patients, including 7 sib pairs, were evaluated with regard to maximum motor ability, mental and convulsion states, cranial CT or MRI findings, and EEG and ophthalmological data. A difference between the sibs in motor ability was apparent in 4 families. Mental status also showed wide variation. Two of 7 sib pairs differed in EEG findings. The familial FCMD patients showed relatively more severe motor disability than that in the sporadic FCMD patients, while in mental and convulsion states no significant difference was found in both groups. Interestingly, in one family hydrocephalus was found in only one of the sibs. In addition, this patient showed encephalocele and retinal detachment at birth. Based on these observations, we consider the clinical spectrum of FCMD to be much broader than previously described and to overlap with that of "mild" WWS and MEBD.

Abnormalities, Multiple↗