Search PubMed⌕ Search

Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 721 records · Page 40Linked to original sources
PubMed1992

Effects of stimulation of the dorsal motor nucleus of the vagus on the extrahepatic biliary system in dogs.

This study was performed to determine the distribution of excitatory and inhibitory areas in the dorsal motor nucleus of the vagus (DMV) for the gallbladder and sphincter of Oddi in spinal cord-transected dogs. Microinjection of 0.5 M L-glutamate into the DMV induced various effects on the gallbladder and sphincter of Oddi. Stimulation at the rostral portion of the DMV elicited only excitatory effects on both motilities. Stimulation at the middle portion of the DMV induced excitatory, inhibitory, or combined effects on the gallbladder and excitatory or combined effects on the sphincter of Oddi. Stimulation at the caudal portion of the DMV elicited the three different effects on the sphincter, but only relaxation of the gallbladder. The locations of the excitatory and inhibitory points for the gallbladder and sphincter were mixed in the DMV at the levels near the obex. From these results, it was concluded that the inhibitory points for the gallbladder and sphincter of Oddi are distributed in the caudal portion of the DMV, while their excitatory points are distributed over a wide area and in the more rostral portion of the DMV.

Animals↗
PubMed1992

Effects of auditory imagery on the detection of a pure tone in white noise: experimental evidence of the auditory Perky effect.

The purpose of this study was to examine whether the auditory image of a pure tone facilitates or interferes with the auditory perception of the pure tone. The masked threshold of a pure tone in white noise with and without the image of a pure tone was compared. It was shown that, in contrast to Farah and Smith's (1983) finding of facilitation, imagery interfered with the detection of the pure tone only when the frequency of the imagined tone and the detected tone was the same. This interference was interpreted as showing the assimilation of the signal tone into imagery, i.e., the effect described by Perky in 1910, occurred in the auditory modality. An explanation of the differences between findings of interference and facilitation is offered.

Adult↗
PubMed1992

A mixture of paraphenylenediamine and imidazole: its effect on the extraction of lipid droplets during electron microscopy staining.

To prevent extraction of lipids during a double staining procedure for electron microscopy, the tissue slices, double fixed with glutaraldehyde and osmium tetroxide to preserve microvesicular lipid droplets in the cytoplasm, were immersed for 2 hr in veronal buffer (pH 9.0) containing 0.5% p-phenylenediamine and 0.5% imidazole immediately after postfixation. The stained sections of the immersed tissue slice showed blackened, well circumscribed lipid droplets similar to those in corresponding unstained sections. Moreover, highly contrasting features of the cellular architecture could be visualized with the double stained, as well as routinely prepared sections.

Adrenal Cortex↗
PubMed1992

[Granulocyte functions of chronic hemodialysis patients].

With increasing number of chronic hemodialysis (HD) patients, urologists share much more chance to encounter HD patients who need urological operations. In these patients healing of surgical wound was sometimes hampered by intractable infection. In this paper we investigated granulocyte functions of HD patients. Thirty two male HD patients (20-50 years of age) and 18 healthy volunteers, who had no infectious foci and had no anti-inflammatory drugs were adopted. Heparinized blood samples were drawn between 8:00 an 9:00 am from the volunteers, and just before HD from the HD patients. The oxygen dependent microbicidal response of granulocytes was evaluated by luminol dependent chemiluminescence which measured the amount of superoxide produced by opsonized zymosan stimulated granulocytes. Phagocytic function of granulocytes was evaluated by counting the number of granulocytes which phagocytized fluorescent monodisperse carboxylated microspheres by flow cytometry. Superoxide production per 1000 granulocytes of HD patients was significantly higher than that of normal control. During HD superoxide production was temporally decreased for the first one hour, became maximal at the end of HD and returned to the baseline level on the second post HD day. Phagocytosis was significantly depressed in HD patients. This functional deficit could lead to prolonged healing of infection in HD patients.

Adult↗
PubMed1992

Positive antinuclear antibody in atopic dermatitis.

Serum samples from atopic dermatitis (AD) patients were examined with two antinuclear antibody-detecting methods, using HEp-2 cells as substrate. 34.0% of 47 AD patients tested with FITC-conjugated polyvalent immunoglobulins (method 1) had positive antinuclear antibody (ANA). 26.3% of 57 AD patients examined with FITC-conjugated anti-IgG (method 2) had positive ANA. We found that AD patients who had facial lesions tended to have positive ANA, whereas severe AD patients tended to have high titres of ANA.

Adolescent↗
PubMed1992

[Classical conditioning of anaphylaxis in sensitized guinea pigs].

An attempt of classical conditioning of anaphylaxis by odor was carried out, using actively sensitized guinea pigs with an inhalation of ovalbumin (OA). One month after sensitization, animals were divided into the conditioned group; group C, and the unconditioned group; group U, consisted of 6 animals, respectively. Dimethylsulfied (DMS: sulfur odor), was inhaled in group C as a conditioned stimulus with OA which is an unconditioned stimulus, while only OA was inhaled in group U. Four days after these procedures, saline was inhaled in group C and DMS was solely inhaled in group U in order to equalize the total inhaled dose of OA and DMS in both groups. These sessions were repeated once a week for seven weeks. After final sessions, all animals were inhaled DMS, saline and OA separately, and blood samples were drawn after each inhalation to measure plasma histamine levels. After an inhalation of DMS only, plasma histamine levels of group C and U were 47.5 +/- 9.7 and 25.7 +/- 1.2 ng/ml, respectively. In group C, plasma histamine levels were 32.9 +/- 4.7 at the inhalation of saline and 59.0 +/- 9.2 ng/ml at OA inhalation. Plasma histamine level after an inhalation of DMS only was significantly higher in group C than that in group U (p < 0.05). These results suggest that the conditional stimulus (DMS inhalation) may induce histamine release in the absence of any antigenic stimulus and support the evidence for mast cell-neuron interaction.

Anaphylaxis↗
PubMed1992

[Coagulation and fibrinolysis in pregnancy].

We studied on coagulation and fibrinolysis systems during pregnancy by measuring plasma levels of thrombin-antithrombin III complex (TAT), plasmin-alpha 2 plasmin inhibitor complex (PIC), fibrinogen/fibrin degradation products (FDP), plasminogen (PLG) and antithrombin III (AT-III). Ninety seven pregnant, 5 post-delivery and 32 nonpregnant women aged from 20 to 52 years old were included in this study. Plasma concentrations of TAT and PIC in nonpregnant women were 3.38 +/- 1.02 micrograms/l and 0.65 +/- 0.24 micrograms/ml, respectively. TAT gradually increased with the progression of pregnancy and rapidly decreased after the delivery. Whereas PIC and AT-III concentrations did not change significantly during pregnancy. Fibrinogen, PLG and FDP concentrations changed similarly as TAT. Eight pregnants whose plasma PIC concentrations elevated more than 1.0 micrograms/l were further examined. In 6 women out of them (71.5%), FDP concentrations were elevated. In this particular group of subjects, however, they delivered normally without complications such as toxemia. These observations suggest that, at least, a hypercoagulative state progresses with pregnancy, being normalized after the delivery. Although we could not find the relationship between the hypercoagulation and clinical complications such as thrombosis and toxemia of pregnancy, present findings suggest that special caution should be paid on the pregnants whose TAT and FDP levels are elevated.

Adult↗
PubMed1992

[The tail suspension test: its theory and practical application].

The tail suspension test (TST) was originally proposed by Steru et al (1985) as a primary screening test of anti-depressant drugs. In this test, it is shown that tail suspension-induced immobility of mice is specifically antagonized by such drugs. More recently, the automated version of TST (ITEMATIC-TST) was developed by the same authors. In the present paper, we described our own device which utilized spring, contactless micro angle potentiometer, A/D converter and personal computer. Results obtained with this apparatus showed that repeated, not single, administration of tricyclic and atypical antidepressants could reverse the immobility of mice. Methamphetamine also activated the behavior, but other psychotropic drugs did not have positive results. Based on these findings, the usefulness and problems of our device were discussed as compared with the original TST.

Animals↗
PubMed1992

[A case of vitello intestinal cyst].

A case of vitello intestinal cyst was reported. A 16-month-old girl was referred to our clinic with a complaint of a cystic mass in the region of the navel. With a diagnosis of urachal cyst, resection of the cyst was performed. Histopathologically, the cyst wall consisted of fibrous and fat tissue, and a small polypoid tumor which was found on the inner surface of the cyst was covered by intestinal epithelia. Pancreatic and gastric mucosal elements were observed in the submucosal layer. The histopathological diagnosis was vitello intestinal cyst. Serum amylase level elevated preoperatively normalized after removal of the cyst. We collected 11 cases of vitello intestinal cyst reported in Japan including the present case. Ectopic pancreatic tissue is considered a characteristic of vitello intestinal cyst and that serum or fluid amylase level may be useful for differential diagnosis of the disease.

Amylases↗
PubMed1992

[Estimation of medroxyprogesterone acetate against a human endometrial tumor constituted from the established Ishikawa cancer cells by a subrenal capsule assay].

In order to establish a sensitivity test system for the evaluation of anti-cancer hormonal agents, we tried a long-term subrenal capsule (SRC) assay, using nude mice with a transplanted solid tumor of endometrial cancer cells (Ishikawa's line). Unlike DNA-affecting agents, anti-cancer hormonal agents exert cytostatic effects rather than cytocidal effects, and their evaluation in a short period is considered to be inaccurate. Our test system is somewhat difficult in terms of technique, but it is useful since it can (1) evaluate the agents in the relatively short period of 28 days and (2) compare the cytostatic anti-tumor efficacy of two or more agents under the same conditions. The rate of successful tumor transplantation in nude mice in our system is very high, i.e., more than 90%. Although there are some points which need improvement, our system is considered to be useful as an assay system for the development of anti-cancer hormonal agents and other similar chemotherapeutic agents for cancers. When medroxyprogesterone acetate (MPA) was evaluated by means of this system, the administration period, as well as the dosage, was found to be important.

Animals↗
PubMed1992

[Effect of high-dose medroxyprogesterone acetate on coagulative and fibrinolytic factors in patients with gynecological cancers].

Medroxyprogesterone acetate (MPA), which is widely used clinically as an anticancer steroid preparation, is a very useful drug that seldom causes severe side effects such as bone marrow suppression, and can be dispensed at the outpatient clinic for an oral administration at home to the advantage of QOL. Recently however, there have been several reports suggesting its relationship with thrombosis. We measured t-PA, protein C, factor X, AT III, TAT, plasminogen, PIC, fibrinogen, and D-dimer in 11 patients with gynecologic malignancies who are treated with MPA (600 mg/day) and 11 controls. Then we examined the effects of the drug on blood coagulation and fibrinolytic activities. No changes in these parameters clearly suggested thrombogenesis in either group at this measurement or during the observation period (17 months at the maximum). The present study found no remarkable abnormalities in the blood coagulation and fibrinolytic activities. Thus, to avoid the use of MPA to patients at risk is considered to be the most important precaution for prevention of thrombosis.

Antithrombin III↗
PubMed1992

[Surgical treatment of myocardial ischemia with cardiogenic shock].

We evaluated the results of surgical treatment of myocardial ischemia with cardiogenic shock in ten patients. Seven of 10 patients survived after surgery. Other three patients died of multiple organ failure (two patients) or severe left ventricular power failure (one patient). Two patients with previous infarction survived. Lesions in the group of survivors after surgery were left main trunk (LMT) disease in one patient, three vessel disease (3VD) in two, 2VD in two and 1VD in two patients. All nonsurvivors had LMT disease. Two patients died in whom preoperative electrocardiography (ECG) had shown Q wave. No significant difference in periods from onset to start of cardiopulmonary bypass (CPB) and from onset to recanalization was found between survivors and nonsurvivors. CPB time and aorta cross-clamp time in survivors were similar to those in nonsurvivors. At 24-hour after operation, pulmonary capillary wedge pressure in survivors showed significantly low value compared to that in nonsurvivors (12.8 +/- 3.9, 19.3 +/- 1.5 mmHg, respectively, p less than 0.05). Four patients out of seven survivors were in 1 of Forrester's classification, two in 2 and one in 3. Of three nonsurvivors, one were in 3 and two in 4. We conclude that mortality related to three risk factors: (1) LMT disease, (2) Q wave in preoperative ECG, and (3) hemodynamic state at 24-hour after operation.

Acute Disease↗
PubMed1992

Histological alterations in renal specimens as indicators of prognosis of IgA nephropathy.

A retrospective clinicopathological study of 66 patients with IgA nephropathy was undertaken to determine the prognostic significance of various renal histopathological alterations and clinical parameters. At the latest follow-up, after a period of 60 to 72 months following biopsy, 18 patients had serum creatinine concentration above 1.8 mg/dl. When the entire patients were evaluated as a whole, the extents of interstitial broadening and glomerular sclerosis were correlated significantly with the final status of renal function: proteinuria of more than 1.0 g per day and mildly impaired renal function at the time of biopsy were also associated with unfavourable outcome. However, when the patients with initially normal renal function, i.e. serum creatinine level below 1.2 mg/dl, were evaluated separately, the initial amount of proteinuria, but none of the other parameters, had a prognostic significance in the subsequent course of renal function. These findings suggest that proteinuria of more than 1.0 g per day as an early event often indicates the progression of IgA nephropathy, and lead to a postulation that renal histopathological changes become more significant prognostic indicators in the relatively advanced stage of the disease.

Adult↗
PubMed1992

[Efficacy and limitations of antiepileptic drug monotherapy for temporal lobe epilepsy].

To evaluate the efficacy of antiepileptic drug (AED) monotherapy, we studied 147 patients with temporal lobe epilepsy (TLE) aged 15 or older who had been undergoing treatment at our hospital for at least five consecutive years. We divided the treatment time into Period I which included one year beginning six months after the initial diagnosis, and Period II which was the two years from January, 1987 to December, 1989. The efficacy of therapy was evaluated for the two periods based on the following standards: effective, if seizures had been controlled, and ineffective, if at least one seizure had occurred during each period. Patients in whom monotherapy was effective increased by a factor of 1.7 over the period of observation, from 38 cases (28%) in Period I to 65 cases (44%) in Period II. The total number of effectively treated cases (including those on polytherapy) also rose from 58 cases (40%) in Period I to 79 cases (54%) in Period II. The average number of AEDs used was reduced from 3.0 +/- 1.3 at the time of initial diagnosis to 1.8 +/- 0.8 in Period I and 1.6 +/- 0.8 in Period II. When compared with the 68 ineffectively treated cases, significant background factors for the 65 effectively treated cases on monotherapy included: higher age at ictal onset, fewer histories of any previous treatment at initial diagnosis, or of encephalitis or febrile seizures, fewer psychological impairments such as cognitive degeneration or personality disorders, lower frequency of seizures, fewer histories of secondary generalization or automatism, and a higher rate of normal findings of background EEG and cerebral CT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Quantitative evaluation of human placental aromatase during pregnancy by ELISA].

To examine the relationship between the modulation of estrogen synthesis and placental maturation during pregnancy, we measured enzyme quantities and catalytic activities of aromatase in 78 normal human placentas (7-41 weeks gestation). The quantity was determined by ELISA with monoclonal antibodies specific to aromatase cytochrome P-450 (P-450arom). The activity was assessed by radioassay with [1 beta-3H] androstenedione. Intracellularly, the P-450arom concentration was twice as great in the microsomal fraction of term placentas (0.18 +/- 0.07%) as in the homogenate and mitochondrial fractions. Aromatase activity was also twice as great in the microsomal fraction as in the other fractions. The P-450arom concentration in microsomes increased linearly as pregnancy progressed (r = 0.759, p less than 0.001). The total P-450arom quantity in the placenta increased quadratically as pregnancy progressed (r = 0.891). Similar results were observed for aromatase activity. These results indicated that the increase in P-450arom was responsible for the increase in aromatase activity in normal human placenta. Therefore, in addition to the increase in placental weight and substrate derived from fetal adrenal during pregnancy, a further increase in P-450arom contributes to the marked increase in maternal estrogen production.

Adrenal Glands↗
PubMed1992

Interferon-gamma-dependent immunosuppressive effects of human gingival fibroblasts.

Immunoregulatory functions of human gingival fibroblasts (HGF) were examined. As in fibroblasts isolated from other tissues, HGF were activated with interferon-gamma (IFN-gamma) to express HLA-DR molecules. Despite the fact that the IFN-gamma-treated HGF showed phenotypical resemblance to so-called antigen-presenting cells (APC), the IFN-gamma-treated HGF were ineffective stimulators of alloreactive peripheral T cells. Conversely, IFN-gamma-treated HGF dramatically inhibited the proliferative responses of allogeneic APC (allo-APC) or phytohaemagglutinin (PHA)-stimulated T cells. Immunosuppressive effects of culture supernatant (CS) of IFN-gamma-treated HGF were low and were completely abrogated by the addition of indomethacin. Moreover, the production of prostaglandin E2 (PGE2) by HGF was not affected by IFN-gamma. These results suggest that IFN-gamma-dependent immunosuppressive effects of HGF were not due to PGE2 produced by HGF. In order to investigate further the mechanism(s) of IFN-gamma-dependent immunosuppressive effects of HGF, activated T cells and IFN-gamma-treated HGF were separately cultured in the same well by collagen films which were assembled in cylindrical cells and disturbed physical interactions between T cells and HGF. The proliferative responses of T cells which directly contacted with IFN-gamma-treated HGF were inhibited more significantly than those of T cells which did not contact with IFN-gamma-treated HGF. This suggests that IFN-gamma-dependent immunosuppressive effects of HGF were mediated by direct interactions between T cells and activated HGF. The present results suggest that IFN-gamma-stimulated HGF would modulate the immune responses of locally infiltrated T cells in periodontal lesions.

Cell Division↗