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Biomedical subjects

N Yasuda

Publications and source records attributed to N Yasuda.

At least 91 records · Page 5Linked to original sources
PubMed1996

Studies on the site of ethanol action in inducing prolactin release in male rats.

Hypersecretion of prolactin (PRL) has been implicated as one of the factors that mediate ethanol-induced hypogonadism, but the site(s) in the central nervous system where ethanol acts to lead to the stimulation of PRL secretion is unknown. To clarify the site(s) of ethanol action, medial basal hypothalamic deafferentation (MBHD) or medial basal hypothalamic ablation (MBHA) were performed stereotaxically in male rats, and their PRL secretory capacity in response to acute ethanol administration was compared with that of intact or sham-operated controls. In intact control rats, plasma immunoreactive PRL concentration increased markedly (P < .001 v saline injection) following ethanol 400 to 500 mg/100 g body weight (BW) intraperitoneally (IP). The PRL response was dose-related and reached a maximum plateau level at 15 minutes. Plasma PRL returned to a near-basal level by 60 minutes. The response was blocked completely (P < .001) by pretreatment with dopamine (1 mg per rat), a specific inhibitor of adenohypophyseal PRL secretion. In sham-operated rats and in MBHD and MBHA rats, ethanol (500 mg/100 g BW IP) induced a significant (P < .001 to .05) elevation of PRL relative to the respective saline treatment. The basal level was significantly (P < .005) lower in the MBHD group (5.3 +/- 0.9 ng/mL) and significantly (P < .001) higher in the MBHA group (101.1 +/- 15.7 ng/mL) than in the sham group (17.2 +/- 5.9 ng/mL). These results suggest the following: (1) acute ethanol administration stimulates PRL secretion from the pituitary in a dose-related manner, (2) ethanol appears to have direct stimulatory effects on adenohypophyseal PRL secretion, and (3) extrahypothalamic brain areas exert a stimulatory influence and the hypothalamus an inhibitory influence on basal PRL secretion.

Animals↗
PubMed1996

Cloning and characterization of a melanin biosynthetic THR1 reductase gene essential for appressorial penetration of Colletotrichum lagenarium.

Melanin biosynthesis of Colletotrichum lagenarium is essential for appressorial penetration of the host plant. A melanin deficient mutant 9141 (Thr-) has a defect in the conversion of 1,3,8-trihydroxynaphthalene to vermelone in the melanin biosynthetic pathway. The mutant formed nonmelanized appressoria and had little infectivity on cucumber leaves. A cosmid clone pCR1 was selected from a cosmid library of wild-type C. lagenarium by means of a heterologous probe BRM2, one of the clustered genes involved in melanin biosynthesis of Alternaria alternata. pCR1 transformed the Thr- mutant 9141 to wild-type phenotype. A DNA fragment (THR1) homologous to BRM2 was subcloned from pCR1 and the nucleotide sequence determined. THR1 contains one open reading frame that encodes a protein of 282 amino acids. A transformant resulting from gene disruption showed a light brown phenotype different from the dark brown phenotype of the wild-type 104-T. The transformant formed nonmelanized appressoria and had little infectivity. The THR1 amino acid sequence contains a region highly similar to the Ver1 gene involved in the conversion of versicolorin A to sterigmatocystin in aflatoxin biosynthesis by Aspergillus parasiticus and to the T4HN reductase gene involved in the conversion of 1,3,6,8-tetrahydroxynaphthalene to scytalone and 1,3,8-trihydroxynaphthalene to vermelone in melanin biosynthesis by Magnaporthe grisea. Expression of the THR1 gene during spore germination of C. lagenarium was detected by RNA blotting. We propose that the C. lagenarium THR1 gene encodes a reductase involved in conversion of 1,3,8-trihydroxynaphthalene to vermelone.

Amino Acid Sequence↗
PubMed1996

In vitro contraction of the canine corpus cavernosum penis by direct perfusion with prolactin or growth hormone.

PURPOSE: It is well established that hyperprolactinemia, most typically seen in prolactinoma patients, causes hypogonadism and impotence. There seems to be a good possibility that hyperprolactinemia causes impotence, at least partially via some intrinsic property of prolactin (PRL), rather than through its suppressive effects on the hypothalamic-pituitary-gonadal testosterone dynamics. In the present investigation, we used an in vitro canine model to attempt to clarify whether direct action of PRL on the corpus cavernosum penis may lead to erectile insufficiency. Growth hormone (GH) and placental lactogen (PL), both having close structural and functional homologies to PRL, were also studied. MATERIALS AND METHODS: Isometric tension measurement with cavernous strips was performed in the presence or absence of 10(-5) to 10(-9) M. PRL, GH, or PL in the perfusion medium. The tension change induced by the test substances was normalized relative to that induced by 120 mEq KCl. RESULTS: Both PRL and GH produced dose-related elevations (p < 0.01) of the cavernous tension, whereas PL and thiol-cleaved PRL in comparable doses were without effect (p > 0.05). When the tension rise produced by 120 mEq KCl was taken as 100%, the maximum contractions produced by PRL and GH were 80% and 110%. The minimum effective concentration was 10(-8) to 10(-7) M. for both PRL and GH. Pretreatment with indomethacin (10(-5) M.), but not tetrodotoxin (10(-5) M., partially suppressed (p < 0.05) the effects of PRL. CONCLUSION: These results suggest that PRL and GH directly and specifically produced contraction of the corpus cavernosum penis, resulting in erectile insufficiency, and that the effect of PRL is partially mediated by prostaglandin.

Animals↗
PubMed1996

Genetic and immunological markers in pouchitis.

OBJECTIVES: Previous studies of the interleukin-1 receptor antagonist (IL-1RN) have found an increased frequency of the associated variable number tandem repeat (VNTR) allele 2 for ulcerative colitis (UC) and further evidence has been reported that this allele is associated with increased severity of several other inflammatory conditions. The HLA type of UC patients has also been implicated in the extent of disease as has the presence of perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA). We therefore decided to test the hypothesis that the p-ANCA, HLA type or the presence of the IL-1RN allele 2 in patients who received a restorative proctocolectomy for UC had an effect on the risk of developing pouchitis. PATIENTS: We determined the genotypes of the IL-1RN and HLA DR beta and DQ beta loci for 28 subjects with previous UC and a pouch with no evidence of pouchitis for a minimum of 2 years after formation of an ileo-anal reservoir (mean 6.3 years; range 2-17 years) and 25 subjects with previous UC and pouchitis confirmed by strict histological examination of pouch mucosal biopsy. The IL-1RN genotypes were also determined for 86 healthy controls and 61 unrelated patients with familial adenomatous polyposis (FAP). The p-ANCA status was determined for all 25 pouchitis subjects but only 23/28 non-pouchitis subjects, with 15 unaffected subjects as a negative control. METHODS: The HLA haplotypes of the UC groups were determined by polymerase chain reaction sequence-specific primer (PCR-SSP) typing and the IL-1RN genotypes were determined by PCR and agarose gel electrophoresis. The p-ANCA status was determined by indirect immunofluorescence. RESULTS: A chi 2 of 5.686 with 1 degree of freedom and a P value of 0.0171 using Yates' correction was obtained by comparing the IL-1RN allele frequencies of the combined UC groups to the FAP controls, and a chi 2 of 6.801 with 1 degree of freedom and a P value of 0.0091 comparing the pouchitis group to the FAP controls. The HLA haplotype frequencies did not vary significantly between groups nor did they correlate with p-ANCA status. There were also no significant associations of the p-ANCA status and pouchitis. CONCLUSION: There is an increased frequency of IL-1RN allele 2 in UC, with the majority of the association arising from the pouchitis group, suggesting that the presence of allele 2 in patients with UC affects the disease outcome. However, the HLA frequencies and p-ANCA status do not have any significant associations.

Adult↗
PubMed1996

Mechanisms of veno-occlusion within and outside the canine corpus cavernosum penis using a pressure-flow technique and cavernoso-venography.

BACKGROUND: Physiological erection of the penis requires multiple mechanisms causing an increase in the arterial blood influx into, and decrease in the venous drainage out of the cavernous space. METHODS: We investigated the extent and location of the venous occlusion that occurs with penile erection within (intrinsic mechanism) and outside (extrinsic mechanism) the corpus cavernosum penis, using 15 adult male mongrel dogs. Under controlled flows produced by a combination of aortic ligation and constant infusion of saline into the corpus cavernosum penis, or into the deep dorsal vein, pressures within the cavernous space or deep dorsal vein were measured before and after electrical stimulation of the pelvic splanchnic (pelvic nerve), the hypogastric, and pudendal nerve. An increase in pressure following nerve stimulations represented an increase in outflow resistance due to occlusion of the venous system. Pre-and post-stimulation radiologic evaluations were performed to determine the site(s) of venous occlusion. RESULTS: Unilateral stimulation of the pelvic nerve caused leftward shift of the corporeal pressure-flow curve. Bilateral stimulation of the pudendal nerve caused a marked rise in deep dorsal vein pressure. CONCLUSIONS: Both intrinsic and extrinsic venous occlusion mechanisms exist and that the former is activated primarily by unilateral stimulation of the pelvic nerve and the latter by bilateral stimulation of the pudendal nerve. The occlusion site for the extrinsic mechanism was localized to where the dorsal vein penetrates the muscles at the base of the pelvis, whereas the precise site for the intrinsic mechanism could not be determined.

Animals↗
PubMed1996

Cloning and structural analysis of the melanin biosynthesis gene SCD1 encoding scytalone dehydratase in Colletotrichum lagenarium.

Appressoria of the phytopathogenic fungus Colletotrichum lagenarium contain melanin, which has been implicated as an important factor in the penetration of host plants. A cDNA clone containing the melanin biosynthetic gene encoding scytalone dehydratase (SCD1) from C. lagenarium was identified by hybridization with a heterologous cDNA probe from Magnaporthe grisea. The cDNA clone was used to identify a cosmid containing SCD1 in a genomic library of C. lagenarium, and the nucleotide sequence was determined for both the cDNA and genomic clones. The SCD1 gene contained one open reading frame composed of 188 codons and two deduced introns of 57 and 67 nucleotides. The deduced amino acid sequence of the N-terminal region of SCD1 showed high similarity to the amino acid sequence of scytalone dehydratase from Cochliobolus miyabeanus. A plasmid containing the SCD1 gene transformed the melanin-deficient mutant 9201Y (Scd-) to the wild phenotype but did not complement the conditional scytalone dehydratase-deficient mutant C. lagenarium 8015. Genomic DNA analysis indicated that the SCD1 gene is a single locus in C. lagenarium. Transcripts of the SCD1 gene were detected 2 h after the start of conidial germination.

Amino Acid Sequence↗
PubMed1996

Isolation of canine parvovirus from a cat manifesting clinical signs of feline panleukopenia.

Twenty-seven feline parvovirus (FPV) isolates were recovered from cats clinically diagnosed with feline panleukopenia (FPL) for assessing antigenic and genomic properties of FPL viruses (FPLV) recently prevalent among cats in Japan. All isolates, with the exception of one novel isolate, FPV-314, possessed homologous properties, and their subgroups in FPVs were identified as FPLV. The FPV-314 isolate, which was from a 1.5-year-old cat which manifested clinical signs of FPL and died on the 13th day after the first medical examination, was finally identified as canine parvovirus (CPV) because it lacked a specific antigenic epitope commonly detected in FPLV and mink enteritis virus and because the nucleotide sequence of the capsid protein gene was almost identical to those of CPV-2a and -2b antigenic type strains recently prevalent among dogs in Japan. The present result together with our previous findings (M. Mochizuki, R. Harasawa, and H. Nakatani. Vet. Microbiol. 38:1-10, 1993) indicates the possibility that CPV and FPLV undergo mutual interspecies transmission between dogs and cats, and it is postulated that they may cause disease in some adventitious hosts.

Animals↗
PubMed1996

Relaxant responses by optical isomers of ephedrine and methylephedrine in guinea pig tracheal smooth muscle.

The effects of optical isomers of ephedrine and methylephedrine on the guinea pig tracheal smooth muscle were studied. l-Ephedrine markedly caused a graded relaxation of the guinea pig trachea where the tone had been raised spontaneously. A rightward shift of the l-ephedrine concentration-response curve was observed for propranolol and butoxamine, and the pA2 values for propranolol and butoxamine were 8.55 and 6.38, respectively. d-Methylephedrine markedly caused a graded relaxation of the guinea pig trachea contracted with histamine. Propranolol and bupranolol did not affect the relaxant response to d-methylephedrine. d-Methylephedrine competitively antagonized the contractile responses to histamine, and the pA2 value for d-methylephedrine was 5.12. These results suggest that l-ephedrine-induced relaxation of the guinea pig trachea is mediated through beta 2-adrenoceptors, whereas d-methylephedrine relaxes the guinea pig trachea by blocking histamine receptors.

Animals↗
PubMed1996

Hydranencephaly, cerebellar hypoplasia, and myopathy in chick embryos infected with aino virus.

Pathogenesis of Aino virus (AIV), a suspected causative agent of congenital abnormalities of calves, has not yet been established by experimental infection of dams. To investigate the pathogenesis, 10(3) median tissue culture infective doses per 0.2 ml of AIV strain JaNAr 28 was inoculated into the yolk sac of 8-day-old chick embryos. At 4, 7, 10, and 13 days post-inoculation (PI) 20 eggs were opened and macro- and microscopic studies combined with virus recovery and immunohistochemical detection of the virus antigen were performed. At 7 to 13 days PI chick embryos manifested marked hydranencephaly, cerebellar hypoplasia, arthrogryposis, and scoliosis, with the highest incidences of 86.7%, 73.3%, 80.0%, and 20.0%, respectively. At 4 days PI the viral antigen was found in nerve cells, gitter cells in mild necrotic foci of the central nervous system (CNS), degenerative myotubules, and macrophages in the interstitium, which was associated with the early phase of AIV-induced encephalitis and polymyositis, with occasional accompanying hemorrhage and clumping of myotubular fragments. From 7 to 10 days PI, AIV antigen increased markedly in the liquefactive necrosis and in both degenerative and normal-looking myotubules in conjunction with developing hydranencephaly and arthrogryposis. The encephalitis and myositis had a tendency to mitigate by 10 days PI, coincident with a slight decrease in amount of AIV antigen. At 13 days PI there was almost no detectable AIV antigen in CNS and skeletal muscles, probably due to depletion of cells having affinity to AIV.

Animals↗
PubMed1996

[Study of components in crude drugs by headspace gas chromatography. II. Components of atractylodes].

Determination of volatile components in essential oils from Atractylodis plants was studied by headspace gas chromatography. The crude drug of 0.20 g with 1.0 ml of water in a capped vial was heated at 130 degrees C for 45 min. Then 0.5 ml of vaporized components were collected by gas tightsillinge, and were applied into the injection port of GC or GC/MS. Consequently we could analyze and confirm the following components; hinesol and beta-eudesmol were found to be contained in Atractylodis Lanceae Rhizoma and atractylon in Atractylodis Rhizoma. beta-Eudesmol was analyzed by headspace gas chromatography, and the obtained calibration curve showed good linearity over the range from 2.5 micrograms to 10.0 mg. The result agreed with those obtained using numerical analyses by the steam distillation method. Atractylodis was found to have a wide variety of components depending on the available sources and on the stored conditions. This method was, therefore, more rapid and simpler determination of essential oils in crude drugs using headspace gas chromatography than those used previously. The method was useful means of the analyses of components in crude drugs such as Atractylodis plants and quality control.

Chromatography, Gas↗
PubMed1996

Creutzfeldt-Jakob disease. A survey of 14 patients.

Creutzfeldt-Jakob disease (CJD) is a transmissible disease of the nervous system causatively related to the presence of an abnormal prion protein, with dementia, myoclonic jerks, and periodic EEG activity. Fourteen patients (7 females and 7 males) ranging from 26 to 76 years of age (median 59 years) were evaluated between 1974 and 1995 at the Neurologic Clinic of São Paulo University School of Medicine. The average duration of the disease was 12 months (3.5-34 months). Early clinical findings were: behaviour changes in 7 patients, dementia in 4, visual disturbances in 4, vertigo in 2, tremor in 9, and dystonia in one. Advanced symptoms were dementia and myoclonus in all patients. Pyramidal tract dysfunction was found in 6, cerebellar ataxia in 2, seizures in 3, nystagmus and vertigo in 4, and peripheral nervous system involvement in 2. Atypical clinical forms were found in 5 patients. Periodic EEG activity was found in 10 patients. Cerebrospinal fluid evaluation showed pleocytosis in 1 patient, higher protein content in 2, and higher gamma globulin level in 2. In 10 patients anatomopathological evidence in the central nervous system confirmed the clinical diagnosis by presenting with status spongiosus. All except one patient presented with the sporadic form of the disease.

Adult↗
PubMed1996

[Matrix metalloproteinase-2 concentrations in squamous cell carcinoma of the head and neck and its clinical significance].

Tumor cells degrade extracellular matrix components (ECM) to invade surrounding tissues. Cancer cells are known to produce various ECM-degrading enzymes including matrix metalloproteinases (MMPs), serine proteinases and cathepsins. Type IV collagen is one of the major components of the basement membrane, and it composes the structural scaffold of these specialized sheets of the ECM. The enzymatic degradation of type IV collagen is initiated by MMPs, in particular MMP-2 (a 72 kDa type IV collagenase) and MMP-9 (a 92 kDa type IV collagenase) which play a key role in cancer invasion and metastasis. In this study, we investigated MMP-2 concentrations and the activity of type IV collagenase in cancer tissue homogenate in 21 cases with head and neck carcinomas and 6 cases with normal mucosa. MMP-2 concentrations did not differ between normal mucosa and tumor tissue without lymphnode metastases. Type IV collagenase activity in normal mucosa was below the detection limit. MMP-2 concentrations had no relation to tumor size, however MMP-2 concentrations in tumor tissue with lymphnode metastases were higher than that in cases without lymphnode metastasis (35.8 +/- 20.5, 20.0 +/- 9.7 ng/mg protein, respectively). However, there was no correlation between MMP-2 concentrations and type IV activity in tumor tissues. These results suggest that MMP-2 plays an important role in tumor invasion and metastasis, so MMP-2 could be a useful biological tumor marker for metastasis and prognosis.

Carcinoma, Squamous Cell↗
PubMed1996

[Left cardiac output curve and pulmonary venous return curve in patients with various heart diseases].

This study assessed the cardiac function of humans by drawing simultaneous left cardiac output and pulmonary venous return curves using radionuclide angiocardiography and right heart catheterization which allows recording of the pressure-flow relationship. Thirty-one subjects with various cardiac diseases were divided into two groups [18 patients with New York Heart Association (NYHA) functional class I and 13 patients with NYHA classes II or III]. Mean pulmonary filling pressure (Pmp) was calculated from the formula of Guyton, using pulmonary arterial compliance which was measured by Reuben's method and pulmonary venous compliance measured as reported previously. On the pressure-flow plane, the down slope of the pulmonary venous return curve was drawn by joining the points of (Pmp, 0) and (mean pulmonary capillary wedge pressure, cardiac output). To construct the cardiac output curve, two levels of lower body negative pressure were used to regulate the venous return to the heart. Pmp and the resistance to pulmonary venous return in NYHA II or III patients were significantly higher than those in NYHA I patients (Pmp: 16.3 +/- 1.5 vs 9.0 +/- 0.5 mmHg, p < 0.01; resistance to pulmonary venous return: 0.75 +/- 0.09 vs 0.43 +/- 0.04 mmHg/l/min, p < 0.01, respectively). The slope of pulmonary venous return curve in NYHA II or III patients was smaller than that in NYHA I patients and the pulmonary venous return curve in NYHA II or III patients shifted rightward. The slope of cardiac output curve in NYHA II or III patients was significantly smaller than that in NYHA I patients. This curve in NYHA II or III patients shifted downward and rightward. These results indicate that simultaneous cardiac output and pulmonary venous return curves may be a useful method for assessing the cardiac function in patients with various heart diseases.

Adult↗
PubMed1996

[Dual biochemical modulation therapy using 5-FU, leucovorin and cisplatin on human rectal carcinoma xenografts in nude mouse].

This study examined a combined treatment for colorectal carcinoma, the dual biochemical modulation therapy, consisting of 5-FU, Leucovorin (LV) and Cisplatin (CDDP). We compared its anti-tumor effects with other treatments: 5-FU alone, CDDP alone and 5-FU with LV. Primary diffuse infiltrated colorectal carcinoma is well known for its biological malignancy and its lack of response to chemotherapy. We used SRM cells from a cell line of carcinoma of the rectum, and subcutaneously injected them into nude mice. The anti-tumor effects were estimated from the growth rate, inhibition rate and thymidylate synthetase inhibition rates in the tumor tissue. Results indicated that even if the concentration of 5-FU and LV were reduced by half, these combined with CDDP were more effective than other therapies. Dual biochemical modulation therapy is particularly promising because the reduction of the dosages would reduce the side effects while still serving as an excellent anti-tumor therapy.

Animals↗
PubMed1996

[Characteristics of pulmonary tuberculosis patients by mode of detection--comparison of patients detected between 1993-94 with those detected between 1986-88].

In a previous study it was concluded that pulmonary tuberculosis (TB) patients who were detected at a hospital, excluding those detected by mass screening (group A), should be classified into three distinct groups. Namely some patients were detected only after the onset of TB symptoms (group B), with the others being treated for other diseases before being diagnosed as having TB (group C). In group C, some patients were detected because of manifesting additional symptoms related to TB such as cough (group C-1), while the remaining patients were detected by chance while being examined for other diseases (group C-2). Four groups respectively had specific characteristics which differentiated each other. The aim of this study is to elucidate changes of proportion and characteristics of group C compared to the former results. Pulmonary TB patients, who were registered between 1993 and 1994, in the area served by Kochi Prefectural Chuo Health Center (N = 332) were compared with those registered between 1986 and 1988 in the area. The results were as follows. 1) The proportion of group C was significantly higher in the period of 1993-94 than during 1986-88. The proportion of elderly people in group C was higher in the period of 1993-1994 than in 1986-88. The proportion of group C is projected to continue increasing as the proportion of elderly among the population increases. 2) The proportion of smear positive cases by sputum was lower in group C-2 than in group B and group C-1. The proportion of either inactive TB or non TB cases was estimated to be higher in group C-2 than in group B and group C-1. 3) In group C-1, the proportion of bacillus positive cases was higher in the period of 1993-94 than 1986-88. The elongation of the interval between the onset of symptoms and diagnosis (total delay) was related to the severity of bacillus finding.

Adolescent↗
PubMed1996

[Sarcoidosis in a patient with autoimmune hemolytic anemia].

A 65-year-old woman was admitted to our hospital because of severe anemia. A skin biopsy was done in January 1994 and sarcoidosis was diagnosed. Diffuse reticular shadows were seen in both lung fields on a chest X-ray film and mediastinal lymph node swelling was seen on a chest CT scan. She was followed as an outpatient and was not treated. She suddenly experienced vertigo and general fatigue in March 1995. Laboratory findings on admission were as follows: Hb 6.2 g/dl, MCV 115.9 fl, Ret 198%, LDH 732 IU/L, I-Bil 1.9 mg/dl, and Coombs' test was positive. Autoimmune hemolytic anemia was diagnosed, and she was treated with prednisolone (1 mg/kg). As of the time of this writing, she has no relapse of hemolytic anemia though prednisolone was discontinued 6 months ago.

Anemia, Hemolytic, Autoimmune↗
PubMed1996

[Supporting roles of health centers in community health practice by municipalities].

Staff of community health centers are expected to support those of municipalities so that they can identify health relevant issues in their communities, plan strategies to resolve the issues, implement them and evaluate the action. To illustrate the role of community health centers, the authors report the process of health promotion practice in Taisho-cho, Kochi prefecture, which was supported by Kubokawa health center. The health center took the initiative in identifying issues in community health through analyzing available information. In a practice setting, the health center facilitated involvement and participation by the residents and cooperated with other community resources. The process of support is discussed from the point of view of community organization practice.

Ambulatory Care Facilities↗