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Biomedical subjects

M Yoshioka

Publications and source records attributed to M Yoshioka.

At least 289 records · Page 16Linked to original sources
PubMed1993

Effect of 5-hydroxytryptamine on glossopharyngeal afferent nerve activity in anesthetized rats.

Excitatory responses to 5-hydroxytryptamine (5-HT) were recorded from the whole glossopharyngeal afferent nerve in anesthetized rats, using an electrophysiological technique. Bolus intravenous injection of 5-HT (6.25-50 micrograms/kg) evoked a dose-dependent excitation of glossopharyngeal afferent nerve activity with a rapid onset and lasting a few seconds. This response was blocked by a selective 5-HT3 receptor antagonist, YM060 (10 micrograms/kg i.v.). A 5-HT3 receptor agonist, 2-methyl-5-HT (6.25-50 micrograms/kg), also produced a rapid and dose-dependent excitation of this nerve activity, and YM060 (10 micrograms/kg i.v.) caused an inhibition of this effect. In contrast, efferent glossopharyngeal nerve activity was not altered by 5-HT even at a high dose (50 micrograms/kg). These results suggest that exogenous 5-HT may elicit excitation of the glossopharyngeal afferent nerve, and that this effect might be mediated via the 5-HT3 receptors on the nerve endings.

Animals↗
PubMed1993

Specificity of the Mnt protein. Independent effects of mutations at different positions in the operator.

The relative binding affinities of Mnt protein are determined for each possible base-pair at position 15 of the operator sequence, and for all combinations of G.C base-pairs at positions 15 and 17. The partitioning of each operator sequence is determined quantitatively with restriction enzymes. At position 15, the wild-type G.C base-pair provides the highest binding affinity but, unlike position 17, the primary distinction is between purine and pyrimidine bases on the top strand. The information content at position 15 is only about 0.16 bit. In comparison with previous measurements at position 17, it is determined that the interactions of the Mnt protein with positions 15 and 17 are independent, i.e. the specific binding energies for the two positions are additive. The relative binding affinities at position 17 are also determined in the background of a G to T mutation at position 5, the position equivalent to 17 on the other half of the symmetric operator. The relative affinities at position 17 are independent of whether position 5 is wild-type or mutant.

Base Sequence↗
PubMed1993

Preoperative in vitro chemosensitivity test of esophageal cancer with endoscopic specimens.

BACKGROUND: From January 1990 to June 1991, the authors tested in vitro chemosensitivity before surgery with endoscopic biopsy specimens from 23 patients with intrathoracic esophageal cancer. METHODS: The authors tested eight anticancer agents using the dye exclusion method, and all 23 patients received chemotherapy with the most sensitive three drugs according to the results of the chemosensitivity test. RESULTS: Ten patients (43.5%) had a tumor reduction of more than 50% on radiologic studies, and 4 patients (17.4%) had a good histologic effect. CONCLUSIONS: The chemosensitivity test is useful in selecting preoperative chemotherapeutic agents for patients with esophageal cancer.

Adult↗
PubMed1993

Campylobacter jejuni strains from patients with Guillain-Barré syndrome belong mostly to Penner serogroup 19 and contain beta-N-acetylglucosamine residues.

Campylobacter jejuni was isolated from stool cultures from 14 (30%) of 46 patients with Guillain-Barré syndrome and from 6 (1.2%) of 503 healthy persons, and the difference was highly significant (p < 0.0001). In addition, serological evidence of recent C. jejuni infection was found in 5 of 29 patients with negative stool cultures. Therefore, 41% of patients were associated with C. jejuni infection. Ten of 12 (83%) isolates from patients with Guillain-Barré syndrome belonged to Penner serogroup 19, which is a rare serogroup in sporadic patients with C. jejuni enteritis. In the lectin typing study, all serogroup 19 strains from patients with Guillain-Barré syndrome were shown to contain terminal beta-N-acetylglucosamine residues on their cell surface, but serogroup 19 strains from patients with enteritis were not.

Acetylglucosamine↗
PubMed1993

Inhibitory effects of clonidine on serotonergic neuronal activity as measured by cerebrospinal fluid serotonin and its metabolite in anesthetized rats.

Clonidine-induced changes in the serotonergic neuronal activity of the central nervous system were estimated by measuring the concentrations of serotonin (5-HT) and its major metabolite, 5-hydroxyindole-3-acetic acid (5-HIAA), in the cerebrospinal fluid (CSF) of anesthetized rats. Clonidine (30 and 300 micrograms/kg, i.v.) led to 74% and 60% reductions in the concentration of 5-HT in the CSF 60 min after administration. CSF 5-HIAA concentrations were also decreased to 77% and 66%, respectively. Clonidine-induced (30 micrograms/kg, i.v.) decreases in CSF 5-HT and 5-HIAA concentrations were attenuated by pretreatment with idazoxan (5 mg/kg, i.p.). Idazoxan by itself did not alter the CSF 5-HT and 5-HIAA concentrations. Decreased CSF 5-HT and 5-HIAA concentrations after i.v. administration of clonidine (30 micrograms/kg) were abolished by noradrenergic denervation after pretreatment with 6-hydroxydopamine (200 micrograms/rat, i.c.v.). These results suggest the possibility that clonidine acts to inhibit the serotonergic neuronal activity, which is mediated via the alpha 2-adrenoceptors. It indicates, moreover, that noradrenergic nervous systems are involved in the clonidine-induced inhibition of serotonergic neuronal activity. Therefore, noradrenergic neurons play a significant role in mediating the actions of clonidine on serotonergic neuronal activity in the rat brain.

Adrenergic alpha-Antagonists↗
PubMed1993

Influence of fatty acid absorption on bidirectional release of immunoglobulin A into intestinal lumen and intestinal lymph in rats.

Effects of absorption of long and middle chain fatty acids on IgA secretion into the intestinal lumen and intestinal lymph and the factors which evoke changes in IgA secretion during the absorptive process were examined in rat small intestine. Bidirectional secretion of IgA from the intestinal mucosa into the intestinal lumen and intestinal lymph was continuously observed in the control condition. Perfusion of oleic acid (a long-chain fatty acid) micelle into the jejunal loop induced a significant increase in IgA output into the intestinal lymph. In contrast, lymphatic output of IgA was significantly decreased when oleic acid micelle was administered intraduodenally. Absorption of octanoic acid, a middle-chain fatty acid, did not produce any significant changes in IgA output into either direction. CR1505, a CCK-receptor antagonist, significantly attenuated the oleic acid-induced increase in IgA secretion into the intestinal lumen, but did not affect the oleic acid-induced decrease in lymphatic IgA secretion. Pluronic L-81, an inhibitor of chylomicron formation and secretion, significantly attenuated the decrease in IgA output into the intestinal lymph during oleic acid absorption without affecting the luminal IgA output. The rate of release of IgA into the intestinal lumen is stimulated by absorption of long-chain fatty acids possibly through the influence of locally released CCK, while the transport process of IgA into lymphatics is controlled by a different mechanism which is closely correlated with the intracellular formation and secretion of chylomicron.

Animals↗
PubMed1993

Detection of tumor necrosis factor-alpha-positive cells in cerebrospinal fluid of patients with HTLV-I-associated myelopathy.

Tumor necrosis factor (TNF)-alpha-positive cells constituted 1.6-18% and 8.2-23.5% of the total number of cerebrospinal fluid cells from six of 12 patients with HTLV-I-associated myelopathy and in all samples obtained from inflammatory cases, respectively. However, in non-inflammatory cases no TNF-alpha-positive cells were detected. These results suggest that some of the infiltrating CSF cells produce TNF-alpha, which plays a role in host immune defenses against causative agents including HTLV-I and in lesion formation within the central nervous system in inflammatory diseases.

Adult↗
PubMed1993

Digitalis-like factors from human urine.

We isolated two candidates for endogenous digitalis-like factors from human urine based on the inhibition of [3H]ouabain binding to intact human erythrocytes. The more-polar ouabain-displacing compound-1 (ODC-1) closely resembled ouabain in biological, physicochemical, and chromatographic properties. Moreover, anti-ouabain IgG dose-dependently neutralized the action of ODC-1. The less-polar ODC-2 behaved identically to digoxin in three analytical high-performance liquid chromatography and thin layer chromatography systems. Fast atom bombardment mass spectrum and proton nuclear magnetic resonance spectrum supported the notion that ODC-2 may be indistinguishable from digoxin. The possibility that substances quite similar to cardenolides are synthesized in the mammalian body must be seriously considered.

Binding Sites↗
PubMed1993

Changes of proliferative activity and phenotypes in spontaneous differentiation of a colon cancer cell line.

We examined the alterations of proliferative activity and c-myc expression of a colon cancer cell line (Caco-2) during its spontaneous differentiation. Caco-2 cells were cultured in various types of media and the degree of differentiation was monitored in terms of dome formation in cell monolayers and expression of alkaline phosphatase (ALP) activity. In Caco-2 cells cultured with Eagle's minimum essential medium (EMEM) containing 10% fetal calf serum (FCS), dome formation was demonstrated and ALP activity was markedly increased after the cells reached confluence. Five-fold reduction of c-myc mRNA and a marked decrease in S-phase cells were observed in the differentiated cells. These changes were not induced in FCS-free EMEM. The addition of insulin and transferrin to FCS-free EMEM did not induce cell differentiation or reduction of c-myc mRNA expression. When Caco-2 cells were cultured with three different serum-free media, the induction of dome formation and the increase of ALP activity were observed to varying degrees. Expression of c-myc mRNA in the cells cultured with one serum-free medium decreased to a level similar to that in fully differentiated cells cultured with EMEM containing 10% FCS. These results suggest that a spontaneous switch from a proliferative state with high c-myc expression to differentiated phenotype occurs after cells reach confluence and depends on the culture conditions.

Cell Differentiation↗
PubMed1993

Sleep disturbance of end-stage renal disease.

Sleep disturbance of patients with end-stage renal disease was examined in a sample of 127 patients receiving hemodialysis (HD) therapy. The results indicate that sleep disturbance occurs quite often. Especially, there was a high incidence of sleep disturbance with prolonged HD therapy and with advancing age, and that somatic complications due to long-term HD indirectly influence sleep disturbance. On the effect of drug therapy, levodopa produced significant clinical effects on RLS compared to ordinary hypnotics. Carbamazepine equally tended to produce favorable clinical effects on RLS.

Adult↗
PubMed1993

Phytogrowth-inhibitory activities of sulfur-containing compounds. II. The inhibitory activities of thiosalicylic acid and dihydro-2(3H)-thiophenone-related compounds on plant growth.

Thiosalicylic acid (I) showed rather strong inhibitory activity on the growth of roots of all plants treated except Abelmoschus esculentus Moench at the concentration of 5.0 x 10(-4) M. This compound strongly inhibited the growth of the root of Echinochloa utilis Ohwi et Yabuno even at the low concentration of 5.0 x 10(-5) M. Dihydro-2(3H)-thiophenone (VII) also exhibited inhibitory activity on the growth of roots of all plants treated except Glycine max Merrill. Both compounds inhibited the germination of seeds of some plants at the concentration of 1.0 x 10(-3) M. In I-related compounds (I-V), methyl acetylthiosalicylate (IV) had the strongest inhibitory activity, while in VII-related compounds (VII-XI), 4-hydroxy-2(5H)-thiophenone (VIII) showed the most potent inhibitory activity. The amount of chlorophyll in the cotyledon of Brassica campestris L. subsp. rapa Hook. f. et Anders treated with all compounds except tetrahydrothiophene (XI) was lower than that of the control group.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1993

[Effects of local anesthetics on rat macrophage phagocytosis].

We examined whether phagocytosis by macrophages (M phi s) is affected by local anesthetics (lidocaine HCl, prilocaine HCl, mepivacaine HCl, tetracaine HCl and procaine HCl). Opsonized zymosan, fetal bovine serum and one local anesthetic were added to each M phi sample. After a 30-min incubation, M phi s were washed to make Giemsa stained slides for counting. The phagocytosis rate was calculated by counting the phagocytosizing M phi s per 200 cells with an optical microscope, and rates for the samples containing local anesthetics were compared with those for the non-treated samples. Inhibition of phagocytosis was reversible, dose-dependent and pH dependent for all local anesthetics. Tetracaine HCl inhibited phagocytosis most and procaine HCl, least. These results suggest that local anesthetics at the level of clinical use inhibit leukocyte phagocytosis and therefore may interfere with the normal function of cells fundamental to host defense.

Anesthetics, Local↗
PubMed1993

Adrenomedullary hyperplasia associated with cortisol producing adenoma.

We report a case of a 58-year-old man with adrenal medullary hyperplasia associated with cortisol producing adenoma. Preoperative examination showed both adrenocortical and adrenomedullary hyperfunction. No Cushingoid sign was present and pheochromocytoma-like symptoms were predominant. Abdominal computerized tomography revealed a left adrenal tumor stained by contrast medium. Histologically, the adrenal tumor was found to be a cortical adenoma, and medullary hyperplasia was observed in the remaining parenchyma.

Adenoma↗
PubMed1993

[Ischemic stroke in childhood].

We have encountered 38 cases of juvenile ischemic strokes during the past 10 years, which included 16 cases of moyamoya disease and 22 cases of non-moyamoya strokes. The etiology could not be determined in most non-moyamoya strokes, except in 4 cases of cardiogenic embolism and 1 case of post-meningitic stroke. We further examined 13 cases of idiopathic strokes, which showed clinical symptoms of so-called acute infantile hemiplegia. Nine out of 13 patients developed strokes between 6 months and 2 years of age. Strong male preponderance was noted, since 11 out of 13 patients were boys. CT scan showed basal ganglionic infarction in the territory of the perforating branches of the middle cerebral artery in 12 patients. Recurrence of ischemic events occurred in none of the patients during the mean follow-up period of 48.4 months. Functional recovery was also good, since no neurological sequelae were found in 5 patients, and the other 8 disabled children were able to go to school without help and none of the children were mentally retarded. These results and a review of the literature suggest the importance of traumatic mechanisms in the etiology and pathogenesis of juvenile idiopathic ischemic strokes of the acute infantile hemiplegic type.

Acute Disease↗
PubMed1993

Prognosis in esophageal carcinoma with cervical lymph node metastases.

BACKGROUND: The purpose of this study was to assess cervical lymph node (C-LN) metastases and to examine whether the site of the C-LN metastasis impacts on survival of the patient with thoracic esophageal cancer. METHODS: Transthoracic esophagectomy and three-field dissection (mediastinal, abdominal, and C-LN) followed by esophageal reconstruction were performed on 68 patients with squamous cell carcinoma of the thoracic esophagus who were seen at our institution from 1983 to 1990. RESULTS: C-LN metastasis was seen in 20 (29.4%) patients, and the survival curve of the 20 patients with positive C-LN metastasis was not significantly different from that of the 48 patients without positive C-LN metastasis. The survival curve of patients (n = 7) with positive node limited to recurrent laryngeal nerve chain node (RLN group) was significantly better than that of patients (n = 13) with positive internal jugular nodes including supraclavicular nodes (IJN group) (p = 0.010; generalized Wilcoxon). This was because there were more patients in the IJN group (84.6%) than in the RLN group (28.6%) (p = 0.022) who had five or more positive nodes in the three fields. CONCLUSIONS: The results suggest that RLN should not be defined as M1 but as N1 in thoracic esophageal cancer.

Age Factors↗
PubMed1993

[Stellate ganglion blocks as the suspected route of infection in a case of cervical epidural abscess].

Spinal epidural abscess is a comparatively rare disease. Its prognosis reportedly depends on degree and duration of the neurological symptoms before the treatment. Thus, the importance of early diagnosis and prompt surgical treatment has been emphasized repeatedly. In the case reported here stellate ganglion blocks were considered to be involved in the etiology of a cervical epidural abscess. The 47-year old woman complained of tinnitus and vertigo and repeatedly underwent stellate ganglion blocks over a period of 10 months. In August, 1991, the patient complained of back pain and developed fever. A few days later she noticed motor weakness and sensory disturbances in the legs. Ten days after the onset of these neurological symptoms she complained of rapidly progressive tetraplegia and was referred to this hospital for admission. On admission, she was fully conscious but febrile. Neurologically, she presented tetraplegia, hypesthesia below level of C7 and slight cervical rigidity. Bladder and bowel dysfunction were also observed. MRI examination showed an epidural mass behind vertebral bodies C6-7 compressing the spinal cord. Antibiotic therapy was initiated immediately and emergency surgical decompression was performed through an anterior approach. Intraoperative findings showed a discitis and yellowish liquid pus in the epidural space. Culture of the pus revealed staphylococcus aureus. In this case repeated stellate ganglion blocks before onset of the symptoms were the suspected route of infection. Postoperative MR images confirmed satisfactory decompression of the spinal cord and motor power was gradually recovered after surgery. Approximately 4 months after surgery she could walk independently. Cervical epidural abscess has been rarely reported as a complication of stellate ganglion block.(ABSTRACT TRUNCATED AT 250 WORDS)

Abscess↗
PubMed1993

Evaluation of 5-hydroxytryptamine concentration in portal vein measured by microdialysis.

Free 5-hydroxytryptamine (5-HT) concentration in the portal vein was monitored in anesthetized rats using microdialysis. The 5-hydroxytryptamine metabolite 5-hydroxyindoleacetic acid (5-HIAA) was also measured. Concentration of 5-HT in the portal vein decreased gradually after insertion of a microdialysis probe but fluctuated markedly throughout the entire perfusion, whereas 5-HIAA values did not fluctuated in the same manner. An electron microscopic study of the probe membrane after dialysis showed platelet adhesion and aggregation on part of the membrane. In contrast, 5-HT concentration measured by puncture and direct blood sampling of the portal vein did not fluctuate in the same way as that determined by microdialysis. These results suggest that measurement of free 5-HT concentration in the blood by microdialysis might be inaccurate due to contamination of 5-HT from adhesion and aggregation of platelets on the probe membrane.

Anesthesia, Inhalation↗