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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 703 records · Page 39Linked to original sources
PubMed1995

Caloric intake stimulates growth hormone secretion in food-deprived rats with anterolateral deafferentation of the medial basal hypothalamus or administered antiserum to somatostatin.

In rats, food deprivation inhibits episodic growth hormone (GH) secretion. On the basis of previous studies, we hypothesized that during a recovery from prolonged fasting, caloric intake stimulates the release of GH-releasing factor (GRF) and this process does not depend on the specific macronutrients in the meal, while protein in the meal acts to restore characteristic ultradian rhythmicity of GH secretion. To test this hypothesis, the effect of caloric intake on GH secretion was examined in fasted adult male Wistar rats devoid of somatostatin (SS) influence on GH secretion either by anterolateral deafferentation (ALC) of the medial basal hypothalamus (MBH) or administration of anti-SS goat serum (ASS). Rats were provided with an indwelling right atrial cannula and were deprived of food for 72 h. ALC was performed 2 weeks prior to the study. ASS was given i.v. 8 h and 7 h prior to refeeding, respectively. Serial blood specimens were collected every 10 min. In rats with ALC (ALC rats) or rats given ASS (ASS rats), the blood GH level revealed irregularly occurring small fluctuations, instead of the usual high bursts and low trough level. The baseline GH level and the mean GH level of fasted ALC rats or fasted ASS rats were significantly lower than those of fed ALC rats or fed ASS rats. Feeding the isocaloric mixed meal, the protein meal or the protein-deficient meal increased the GH pulse frequency, the pulse amplitude, the baseline GH level and the mean GH level in 72-h fasted ALC rats. These changes in GH secretory pattern persisted during the period of observation and were independent of the type of meal ingested. Following feeding the mixed meal, similar changes in the GH secretory pattern demonstrated in 72-h fasted ALC rats were also observed in 72-h fasted ASS rats, suggesting that the stimulation of GH secretion following caloric intake is not limited to ALC rats. Since the influence of SS on GH secretion has been largely eliminated in ALC or ASS rats, it is highly unlikely that the augmentation of GH secretion following feeding after prolonged food deprivation was the consequence of inhibition of SS secretion. Although GRF measurement was not performed, it is conceivable that the signal of caloric intake is conveyed to the MBH and acts to stimulate GRF release.

Animals↗
PubMed1995

Fibrinolytic activity in liver tissues of stroke-prone spontaneously hypertensive rats.

1. Plasminogen activator activity was detected in the extract solution of the liver tissues of both stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto (WKY) rats by the synthetic substrate assay. 2. The total PA activity in the liver extract of WKY (26.8 +/- 8.3 i.u.) was about 1.5-fold higher than that of SHRSP (18.5 +/- 4.1 i.u., n = 8, P < 0.005). 3. The enzymography of the liver extract revealed three lytic bands with a molecular weight of 67 kDa, 44 kDa and 38 kDa. 4. The inhibitor activity of the liver extract was detected by the reverse fibrin autography method with one lytic resistance band at 70 kDa. 5. Thus, fibrinolytic components exist in the liver tissue of both strains of rats, but their contribution to the stroke requires further study.

Amino Acid Sequence↗
PubMed1995

Pericardial malignant mesothelioma: case report and discussion of immunohistochemical and histochemical findings.

An extremely rare case of malignant mesothelioma of the pericardium is reported. The tumor appeared to be the biphasic type of diffuse malignant mesothelioma which present many small to fine lipid droplets in the cytoplasm, particularly that of the epithelial cell, and a positive immunohistochemical reaction with antibodies to low molecular weight cytokeratin (45-50 kDa) in all of the tumor cells. The literature is also reviewed and the presence of lipid droplets and the importance of the immunohistochemical positivity to low molecular weight cytokeratin for differential diagnosis from other malignant tumors, such as invasive adenocarcinoma or primary sarcoma of the pleura, or soft tissue sarcoma involving the pleura is discussed.

Aged↗
PubMed1995

Recurrent pneumococcal meningitis in a patient with transient IgG subclass deficiency.

We report the case of a 3 year old boy who exhibited recurrent serious infections with a transient imbalance of IgG subclass in the second year of life. He suffered from pneumococcal meningitis at 3 months, hepatitis at 9 months, and purulent arthritis at 11 months of age. The second episode of pneumococcal meningitis occurred at 14 months. Serum IgG level was normal for age. Low level of IgG2, undetectable level of IgG4 and negligible level of pneumococcus-specific IgG1-G2 antibodies were found. No other primary immunodeficiency was apparent. Serum IgG2-G4 levels but not pneumococcus-specific IgG1-G2 titers increased by the age of 30 months. At that time, he was inoculated with a polyvalent pneumococcal vaccine along with acellular diphtheria-pertussis-tetanus vaccine. He acquired the immunity against these agents, and had no episodic infections in the following 2 years. This observation stresses the existence of transient IgG subclass deficiency associated with delayed development of the anti-polysaccharide antibody response.

Child, Preschool↗
PubMed1995

Long-term sequential changes of antibody to p40tax in HTLV-I carrier mothers and children.

Antibody to p40tax (anti-p40tax) in serum specimens obtained sequentially from a human T cell lymphotropic virus type I carrier population of mothers and children were assayed. The prevalences of anti-p40tax at the initial sampling were 88% (7/8) in children and 55% (16/29) in mothers. Two of the seven positive children lost their anti-p40tax during the investigation period, resulting in a final prevalence of 63% (5/8) in children. However, anti-p40tax status was constant in all the 22 mothers with multiple serum samples (15 remained positive and seven remained negative). A decline in the absorbance value of EIA for anti-p40tax was observed in seven of the 15 anti-p40tax positive mothers. This decline may result in the disappearance of anti-p40tax in some of them.

Adolescent↗
PubMed1995

Prognostic significance of microvessel count in low stage renal cell carcinoma.

BACKGROUND: It has been postulated that tumors beyond a certain size are dependent on angiogenesis, which might also be related to distant metastasis. We therefore assessed the prognostic significance of tumor microvasculature in renal cell carcinoma. METHODS: Tumor specimens from 84 patients with primary renal cell carcinoma were examined by immunohistochemical staining for factor VIII. Individual microvessels were counted in a 200 x field overlying the area of highest neovacularization. RESULTS: The mean number of microvessels in patients with metastases was significantly higher than that in patients who were disease-free for more than three years (P = 0.004). The survival of patients with less than 30 microvessels per 200 x field was significantly higher than that of patients with more than 30 microvessels per 200 x field (P = 0.007). Multivariate analyses revealed that these microvessel counts were the only significant predictor of prognosis in 45 patients with T1-2 and M0 tumors (P = 0.028). CONCLUSIONS: Assessment of tumor microvasculature is therefore probably one of the most important prognostic predictors in renal cell carcinoma.

Adult↗
PubMed1995

Single-step purification of prostatic acid phosphatase: immunoaffinity chromatography with a monoclonal antibody.

BACKGROUND: Prostatic acid phosphatase (PAP) is an important protein which should be studied further as a tumor marker or as a biologically functional molecule. The purpose of the study was to establish a simple and reliable method to obtain highly pure PAP. METHODS: Spleen cells from mice immunized with prostatic epithelial cells prepared from benign prostatic hyperplasia tissue were fused with myeloma cells X63Ag8-653. Hybrid cells of interest were selected using the indirect immunofluorescence method with unfixed frozen tissue sections. One clone of the hybrid cell lines was established which secreted the monoclonal antibody specifically reactive to prostatic acid phosphatase. Using this monoclonal antibody, we purified the antigen from human prostatic tissue by means of single-step immunoaffinity chromatography. RESULTS: SDS-PAGE profiling under reducing conditions indicated that the protein recognized by this antibody consisted of several components of molecular weight 41,000-45,000. Partial amino acid sequence analysis of this protein indicated that these components involved a heterogeneously modified single polypeptide, and that this antigen is identical to human prostatic acid phosphatase. CONCLUSIONS: This single-step method saves the time needed to purify prostatic acid phosphatase and requires only half a day for the whole procedure. Moreover, the purity of the isolated protein was extremely high. This method seems to be useful not only for purifying prostatic acid phosphatase but also for purifying other proteins from the prostate gland and for analysis of antigenic macromolecules.

Acid Phosphatase↗
PubMed1995

[Studies on maternal transmission of HIV-1].

To investigate HIV-1 transmission from mother to child, samples taken from 3 HIV-1 sero-positive pregnant mothers, 3 children born by caesareans from their mothers and therapeutic abortion from 2 HIV-1 sero-positive mothers were tested for HIV-1 antibody by westernblot, p24 antigen by antigen captured ELISA, proviral DNA by Nested-PCR and isolation of HIV-1 virus from peripheral blood, cord blood, amniotic fluid and placenta. HIV-1 proviral DNA was detected in the peripheral blood of all mothers, but p24 antigen and virus isolation were not detected. None of the HIV-1 markers, except for antibody, was detected in the samples from their children and placenta. These facts strongly suggest that there was no HIV-1 transmission from mother to child.

AIDS Serodiagnosis↗
PubMed1995

[Prevalence of pertussis in Fukuoka: incidence and MICs of antibiotics for Bordetella pertussis isolate].

For bacteriological examinations of whooping cough patients, nasopharyngeal specimens were directly inoculated on the cyclodextrin solid medium (CSM) supplemented with 5 micrograms of cephalexin (CEX) per ml. The inoculated plates were cultured in an incubator at 35 degrees C for 3 to 7 days. During the period from 1990 to 1993, B. pertussis (43 strains) and B. parapertussis (1 strain) were isolated from 145 whooping cough patients and 34 relatives. B. pertussis were isolated sufficiently in June to December during the year. It was suggested that during this period epidemics of whooping cough occurred. All isolates of B. pertussis had K antigen consisting of 1, 3, and 6. The determination of minimal inhibitory concentrations (MIC) of antibiotics to B. pertussis was carried out by the micro dilution technique modified from the standard methods. The Stainer-Scholte broth, supplemented with heptakis (2,6-O-dimethyl) beta-cyclodextrin, was used for dilution of the drug, and also for cultivation of bacteria. For determining susceptibility of bacteria to antibiotics, twenty seven isolates of B. pertussis and one of B. parapertussis were precultured on CSM at 35 degrees C for 2 days. The turbidity of broth cultures was adjusted to that of McFarland no. 0.5, and diluted to the concentration of 10(6) CFU/ml. One hundred microliters of these suspensions were added to 25 microliters of each antibiotic solution. After incubation for 3 days at 35 degrees C, the turbidity of the bacteria was read macroscopically for determining the MICs. On the other hand, we compared the agar dilution MICs of 23 antibiotics to the broth microdilution MICs for 27 B. pertussis isolates.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1995

A novel method to chemically immobilize antibody on nylon and its application to the rapid and differential detection of two Vibrio parahaemolyticus toxins in a modified enzyme-linked immunosorbent assay.

A new method of chemically immobilizing antibody on nylon was developed. The method consists of serial treatments with HCl, polyethylene imine, and maleic anhydride methylvinyl ether copolymer, which resulted in the stable immobilization of sufficient amounts of antibodies on nylon. This principle was used to differentially detect two immunologically related but nonidentical hemolysins (thermostable direct hemolysin [TDH] and TDH-related hemolysin [TRH]) of Vibrio parahaemolyticus in a modified enzyme-linked immunosorbent assay with antibodies immobilized on nylon slips (NSIT). The results (dark purple color on nylon slips) were easily evaluated by the naked eye. The results with NSIT were compatible with those obtained by using DNA probes or a conventional bacterial culture test, not only with cultured specimens but also with clinical specimens (diarrheal stool samples). Furthermore, the NSIT differentially detected TDH and TRH in a single test. The antibody immobilization method developed here is applicable to various immunological detection methods and may improve their sensitivity and specificity.

Animals↗
PubMed1995

The earliest site of atrial activation in patients with isomeric appendages.

BACKGROUND: The sinus node is known to be duplicated in hearts with bilateral right appendages, but its site is uncertain when both appendages are of morphologically left pattern. OBJECTIVE: To determine the earliest site of activation of the atria, and to assess this site of activation relative to the anticipated location of the sinus node in patients with isomeric atrial appendages. STUDY DESIGN: Electrophysiological recordings by epicardial mapping during operations through a median sternotomy. PATIENTS: Since 1987, 44 consecutive patients with isomeric right appendages and 23 with isomeric left appendages. RESULTS: In 77% of the patients with isomeric right appendages, the site of earliest activation was superiorly located at the junction of one or other atrium and a superior caval vein; in other words, in the anticipated site of a sinus node. In contrast, an inferior site of earliest activation at the junction of an atrium with an hepatic vein was most common in patients with isomeric left appendages (56%). The site of earliest activation was not related to the veno-atrial junctions in six patients with isomeric right appendages (14%), nor in five with isomeric left appendages (22%). Moreover, in six patients with isomeric right appendages (13%), and three with isomeric left appendages (13%), additional sites of earliest activation were observed when the dominant site was suppressed. The locations of the earliest activation observed by epicardial mapping did not always accord with those expected from the preoperative electrophysiological examination, nor did they always match the anticipated site of the sinus node as documented by previous histological investigations. CONCLUSIONS: Epicardial mapping showed marked variation in functional arrangement of the earliest atrial activation. This information could be of future use when planning surgical procedures.

Electrocardiography↗
PubMed1995

Monocyte chemoattractant protein 1 inhibits growth of rat vascular smooth muscle cells.

The early atherosclerotic lesion is characterized by the migration of inflammatory cells, including monocytes, which may serve as a source of cytokines such as monocyte chemoattractant protein 1 (MCP-1), a homologue of mouse JE. We investigated the effect of MCP-1 on the growth of vascular smooth muscle cells (VSMC) isolated from rat aortae. In Northern blot analysis, MCP-1/JE transcripts were not observed in unstimulated VSMC, but its expression was clearly observed by exposure to lipopolysaccharide (1 micrograms/ml) for 6 h. Human recombinant MCP-1 inhibited the uptake of [3H]thymidine by VSMC cultured in 0.5% fetal bovine serum (FBS) containing Dulbecco's modified Eagle's medium (DMEM) in a dose-dependent manner. The inhibitory effect of MCP-1 on the growth of VSMC was also confirmed by a change in cell counts. The antiproliferative effect of MCP-1 was significantly blocked in the presence of an anti-MCP-1 antibody. MCP-1-induced inhibition of [3H]thymidine uptake was not affected in the presence of indomethacin (1 micrograms/ml) or NG-monomethyl-L-arginine (0.1 mM), and MCP-1 showed no effect on 6-ketoprostaglandin F1 alpha, guanosine 3',5'-cyclic monophosphate, and adenosine 3',5'-cyclic monophosphate syntheses in VSMC. These results indicate that MCP-1 inhibits the proliferation of VSMC in vitro and that its effect is independent of prostaglandin or nitric oxide generation.

6-Ketoprostaglandin F1 alpha↗
PubMed1995

Acute interstitial nephritis and uveitis with bone marrow granulomas and anti-neutrophil cytoplasmic antibodies.

Acute interstitial nephritis (AIN) and uveitis of unknown etiology developed in a 15-year-old girl. Symptoms and urinary abnormalities improved spontaneously but moderate renal dysfunction and anterior uveitis persisted. A repeat biopsy performed 2 years later showed focal tubulointerstitial changes, while bone marrow examination revealed granulomas. Simultaneously, antineutrophil cytoplasmic antibodies (ANCA) were detected, and decreases in T cell population and lymphocyte function were found. These immunological abnormalities normalized in parallel with clinical improvement with corticosteroid therapy, strongly suggesting that in some patients autoimmune disorders contribute to the pathogenesis of the disease.

Acute Disease↗
PubMed1995

Contribution of endothelin-1 to warm ischemia/reperfusion injury of the rat lung.

The purpose of the present study was to clarify the role of endothelin-1 (ET-1) in the pathogenesis of ischemia/reperfusion lung injury and to determine whether pretreatment with an ET receptor antagonist prevents such injury. The left lung of Sprague-Dawley rats was subjected to 60 min of no-flow warm ischemia followed by 90 min of reperfusion. The plasma ET-1 concentration increased significantly after reperfusion compared with before and after ischemia (p < 0.05). Arterial oxygen tension was reduced, and the lung tissue wet/dry weight ratio increased in post-reperfusion lungs compared with both pre-ischemia and post-ischemia lungs. Histologic study showed pulmonary edema, hemorrhage, hyaline membrane formation, and a significant increase in lung tissue neutrophils after reperfusion. In addition, the expression of ET-1 mRNA was determined by Northern blot analysis. Although ischemia did not significantly alter ET-1 expression, reperfusion increased expression in the left lung markedly and in the right lung moderately. Pre-infusion of FR139317, an ETA receptor antagonist, prevented post-reperfusion damage to the lung. These results suggest that ET-1 contributes to the ischemia/reperfusion injury of the rat lung, mediated by an ETA receptor, and that an ETA receptor antagonist may inhibit ischemia/reperfusion lung injury.

Animals↗