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Biomedical subjects

Y Murakami

Publications and source records attributed to Y Murakami.

At least 127 records · Page 7Linked to original sources
PubMed2001

[A case of lung cancer underwent carinal resection with right upper lobectomy and carinal reconstruction with double-barreled anastomosis].

A 70-year-old male complaining cough was admitted to our hospital. Bronchoscopic examination revealed a tumor mass which occluded the orifice of the right upper lobe. Chest computed tomographic (CT) scans gave the image of tumor invasion at the carina. The pathological diagnosis of the tumor was squamous cell carcinoma. Operation was accomplished by right posterolateral thoracotomy approach through the fifth rib bed. The carinal resection with right upper lobectomy was followed by a double-barreled anastomosis of the right intermediate trunk and left main-stem bronchus into the carina. The operation was successfully performed and was considered curative. The length of resected airway measured 4.0 cm from tracheal line of resection to the divided the right intermediate trunk. Reinforcement of the anastomosis was not performed in this case. No postoperative complication occurred but mild ischemia of the anastomosis. The patient died of recurrent tumor in a year and 2 months after operation.

Aged↗
PubMed2001

[Knowledge, behavior, and attitudes toward sex among adolescent students at a junior/high school in Cote d'Ivoire].

OBJECTIVES: To be able to provide appropriate information about sex to adolescent students in the Cote D'Ivoire, we conducted a study to determine knowledge, behavior, and attitudes toward sex. METHODS: We conducted a cross-sectional study at a junior/high school using a self-administered questionnaire which contained students' characteristics (age, sex, grade, tribe, region), their knowledge about sex, sexual behavior (including experience of sex and contraception), and attitudes toward sex. Knowledge about sex and proportions employing contraception were compared between males and females and between the lower and the upper grades. We also examined associations between attitudes toward sex and contraception. RESULTS: A total of 695 (males: 278, females: 417) students filled in our questionnaire (response rate: 33.1%). The proportion of the students who had experienced sex was 84.2% for males, 46.5% for females, and the average age of the first sex was 14.3 and 15.6 years in males and females, respectively the proportions using contraception was 49.6% and 46.9%. In students of the lower grades, males had greater knowledge than females, but this difference was reduced with progression through the upper grades. The proportion using contraception in the upper grades was also higher and an association between attitude toward sex and contraception was clear. CONCLUSION: Adolescent students' knowledge, behavior, and attitudes toward sex could be relatively easily investigated at a junior/high school of Cote D'Ivoire. The majority of males and half of the females in this setting already had experience of sexual intercourse. The study showed that difference in sexual knowledge between males and females shrunk with increase in school grade. We also showed an association between attitude toward sex and contraception.

Adolescent↗
PubMed2001

Drop in plasma brain natriuretic peptide levels after successful direct current cardioversion in chronic atrial fibrillation.

BACKGROUND: According to previous reports, plasma atrial natriuretic peptide levels increase in atrial fibrillation (AF) and decrease after successful direct current (DC) cardioversion, but there have been no reports on plasma brain natriuretic peptide (BNP). OBJECTIVE: To determine whether plasma BNP levels decrease after successful direct DC cardioversion in patients with chronic AF. PATIENTS AND METHODS: Twenty patients who remained in sinus rhythm for at least seven days after cardioversion, and 20 normal control subjects, were studied. Group A consisted of 10 patients with underlying heart disease, including dilated cardiomyopathy (n=2), hypertrophic cardiomyopathy (n=1), mitral valve disease (n=3), hypertensive heart disease (n=3) and status after atrial septal closure (n=1). Group B consisted of 10 patients with just AF. Group C (serving as controls) comprised 20 subjects with normal sinus rhythm and no risk factors. RESULTS: Before cardioversion, plasma BNP levels were higher in group A (176.7+/-128.1 ng/mL) and in group B (96.8+/-51.7 ng/ml) than in group C (6.3+/-3.8 ng/ml) (P<0.01 for all). After successful cardioversion, mean plasma BNP levels in groups A and B decreased from 136.8+/-105.5 ng/mL to 46.4+/-44.2 ng/mL (P<0.01). In group A, plasma BNP levels decreased from 176.7+/-128.1 ng/mL to 62.5+/-54.6 ng/mL (P<0.01), and in group B, plasma BNP levels decreased from 96.8+/-51.7 ng/mL to 30.3+/-23.8 ng/mL (P<0.01). CONCLUSIONS: Lone AF raises plasma BNP levels, which is more marked if there is underlying structural heart disease present, and cardioversion reduces plasma BNP levels. Therefore, high plasma BNP levels in patients with chronic AF are likely to be caused by AF and reflect cardiac overloading associated with, although contributed to in part by, underlying heart diseases.

Adult↗
PubMed2001

Functional comparison of the single-layer agarose microbeads and the developed three-layer agarose microbeads as the bioartificial pancreas: an in vitro study.

In this study, the insulin secretory characteristics of the microencapsulated hamster islets were studied during long-term culture. The hamster islets were encapsulated as single-layer agarose microbeads or three-layer agarose microbeads with agarose and agarose containing poly(styrene sulfonic acid) (PSSa), respectively. The influence of PSSa on the function of the rat islets microencapsulted in three-layer microbeads was primarily monitored. The aim of this study was to examine the influence of the PSSa on the in vitro function of the islets encapsulated in the agarose/PSSa microbeads compared with single-layer agarose microbeads during long-term culture. The microbeads were cultured for 30 days in medium of Eagle's MEM at 37 degrees C in 5% CO2 and 95% air. The basal insulin secretion into the culture medium was measured daily during the first 12 days and two times per week until 30 days. The microbeads were subjected to static incubation test on the 10th, 20th, and 30th day during culture. The basal insulin secretion level of the agarose/PSSa microbeads was significantly higher than that of single-layer agarose microbeads. The static incubation tests revealed a similar pattern of insulin secretion from both microbeads when they were exposed to high glucose challenge. In the static incubation test, both could significantly increase insulin release to more than 6.61 times (stimulation index) in response to high glucose stimulation and could significantly decrease when glucose concentration returned from high glucose to low glucose on the 10th, 20th, and 30th day of culture. This study demonstrated that the hamster islets enclosed in agarose/PSSa hydrogel not only continuously secreted basal amounts of insulin, but also maintained their response to high glucose stimulation similar to the agarose microbeads. The above results together with those of our previous in vivo study suggest that the three-layer microbeads (agarose/PSSa) are well suitable for xenotransplantation of islets for the clinical application.

Animals↗
PubMed2001

[Is the bronchoscopic criteria of early lung cancer valid?].

We studied the validity of the bronchoscopic criteria of the early lung cancer using the surgical specimen excised between 1980 and 1999. Twenty-four cases with squamous cell carcinoma of the lung of clinical stage I were located subsegmental or more proximal bronchi and trachea, and the size less than 20 mm in greatest dimension. We histopathologically investigated the endoscopic features in relation to the width of superficial extent, the depth of cancer invasion, and lymph node metastasis. Tumors of the thickened type lesions less than 20 mm in greatest dimension showed no invasion into the cartilaginous layer and no lymph node metastasis. On the other hand, in the nodular and polypoid types, invasion beyond the cartilaginous layer was observed more or less, and lymph node metastasis was observed in 1 case. These cases would not be suitable for bronchoscopic (photodynamic) therapy. In conclusion, the bronchoscopic criteria of early lung cancer is valid in the thickened type, but not in the nodular type or polypoid type.

Aged↗
PubMed2000

X-Ray anomalous scattering study of a charge-ordered state in NaV2O5

Charge ordering of V4+ and V5+ in NaV2O5 has been studied by an x-ray diffraction technique using anomalous scattering near a vanadium K-absorption edge to critically enhance a contrast between the two ions. A dramatic energy dependence of the superlattice intensities is observed below T(C) = 35 K. The charge ordering pattern is the fully charged zigzag-type ladder with the unit cell 2ax2bx4c, but not the chain-type originally proposed for the spin-Peierls state. Charge disproportionation suggested in our model as the average valence V(4.5+/-delta(c)/2) is observed below T(C), showing continuous variation of delta(c) as a function of temperature.

Journal Article↗
PubMed2000

Contribution of endogenous nitric oxide to basal vasomotor tone of peripheral vessels and plasma B-type natriuretic peptide levels in patients with congestive heart failure.

OBJECTIVES: We examined whether a relationship exists between the vasoconstrictive response to endogenous nitric oxide (NO) synthesis inhibition and the severity of heart failure in patients with congestive heart failure (CHF). BACKGROUND: Controversy exists as to whether the vasoconstrictive response to NO synthesis inhibition in patients with CHF is comparable to that in normal subjects or is enhanced. METHODS: Forearm blood flow (FBF) and calculated forearm vascular conductance (FVC) were obtained using plethysmography before and after administration of the NO synthesis inhibitor L-NMMA (NG-monomethyl-L-arginine) in 40 patients with CHF due to dilated cardiomyopathy and in 16 normal control subjects. Basal plasma B-type natriuretic peptide (BNP) and nitric oxide concentrations were measured in all subjects. RESULTS: Plasma BNP and nitrite/nitrate (NOx) levels in the patients group were significantly greater and baseline FBF was significantly less. Administration of L-NMMA significantly decreased FBF and FVC in both groups. The percent changes in FBF (%FBF) and FVC (%FVC) from the baseline after L-NMMA correlated significantly with plasma BNP level (%FBF: r = 0.72; %FVC: r = 0.76; both p < 0.001). Percent changes in both FBF and FVC were greater in patients with BNP > or = 100 pg/ml than in normal subjects; however, in patients with BNP < 100 pg/ml they were comparable to those in normal subjects. CONCLUSIONS: Vasoconstrictive response to L-NMMA in patients with CHF was preserved or enhanced in proportion to the basal plasma BNP level, indicating a close relationship between the contribution of endogenous NO to basal vasomotor tone and the severity of heart failure.

Adult↗
PubMed2000

Stimulating effect of erythropoietin on the release of dopamine and acetylcholine from the rat brain slice.

We investigated the effects of erythropoietin (EPO) in rat hippocampal and striatal slices, where EPO receptors have been known to exist. EPO stimulated dopamine release from rat striatal slices. Acetylcholine (ACh) release from rat hippocampal slices was not affected by EPO, but high K(+)-induced ACh release was considerably enhanced by EPO. Nitric oxide (NO) production from the hippocampus and the striatum was not affected by EPO. NO-synthase activity was not changed by EPO in the hippocampus or the striatum. These results suggest that EPO stimulates dopamine- and acetylcholine-release without affecting NO production.

Acetylcholine↗
PubMed2000

Effects of dopamine and L-DOPA on survival of PC12 cells.

The effects of dopamine and L-DOPA on survival were examined in differentiated PC12 cells. Addition of dopamine to the culture medium at 3-30 microM prevented cell death induced by depletion of serum and nerve growth factor (NGF). At 100 microM, dopamine induced cell death. The cell-protective effect of dopamine was not affected by nomifensine, an inhibitor of dopamine uptake, or pargyline, an inhibitor of monoamine oxidase, suggesting that dopamine is working outside the cell. The cell-protective effect of dopamine was blunted by SCH-23390, a D(1) antagonist, but not sulpiride, a D(2) antagonist, indicating that the cell protective effect of dopamine is mediated by D(1) receptors in PC12 cells. L-DOPA also protected PC12 cells from cell death induced by depletion of serum and NGF at low concentrations and showed toxicity at high concentration. The effect of L-DOPA was unchanged after inhibition of conversion of L-DOPA to dopamine by m-hydroxybenzylhydrazine (NSD-1015), an inhibitor of DOPA decarboxylase, suggesting that L-DOPA itself is working for cell protection. Intracellular Ca(2+) concentration and mitogen-activated protein (MAP) kinase activity were increased by both dopamine and L-DOPA. The effects of dopamine and L-DOPA on cell survival were blunted by nicardipine, a Ca(2+) channel blocker, and PD-98059, an inhibitor of MAP kinase kinase (MEK). These results taken together raised the possibility that dopamine and L-DOPA protect PC12 cells from cell death at low concentrations by activating MAP kinase activity via elevation of intracellular Ca(2+) concentration.

Animals↗
PubMed2000

Study of complement activation on well-defined surfaces using surface plasmon resonance.

It has been accepted that covalent immobilization of C3b on artificial materials is the most important step to initiate the complement activation. However, there are few studies that have directly demonstrated covalent immobilization of C3b on artificial surfaces. In this study, model thin layers were prepared by the self-assembled monolayer method to produce a surface covered with hydroxyl or methyl groups using mercaptododecane (CH(3)-SAM) and mercaptoundecanol (OH-SAM). Interactions of the complement system with the model surfaces were studied using a surface plasmon resonance instrument. The OH-SAM immobilized C3b, resulting in activating of the complement system through the alternative pathway in Veronal-buffered saline, but this surface did not activate the classical pathway. However, the OH-SAM could not activate the alternative pathway in Veronal-buffered saline containing 10 mM EGTA and 2 mM MgCl(2) that is believed not to interfere with the activation of the alternative pathway. The hydrophobic CH(3)-SAM surface could not activate the classical pathway, but activated the alternative pathway, although the extent was small.

Journal Article↗
PubMed2000

Characterization of nicotinic acetylcholine receptor-mediated noradrenaline release from the isolated rat stomach.

We characterized nicotinic acetylcholine receptor-mediated noradrenaline release from the isolated, vascularly perfused rat stomach. The stomach was perfused via the coeliac artery with Krebs-Ringer solution at a constant flow rate of 4 ml per minute. Endogenous noradrenaline released into the perfusate was electrochemically measured using high-performance liquid chromatography. Nicotinic receptor agonists were applied once into the perfusion medium for 2 min and nicotinic receptor antagonists were administered throughout the experiments. The (-)-nicotine (3x10(-5) M)-induced noradrenaline release was abolished by tetrodotoxin and hexamethonium and partially blocked by dihydro-beta-erythroidine (up to 10(-5) M) (a relatively selective antagonist of alpha4beta2 nicotinic receptors) and abolished by mecamylamine (10(-5) M) (a relatively selective antagonist of alpha3beta4 nicotinic receptors), but not influenced by alpha-bungarotoxin (3x10(-7) M) or alpha-conotoxin ImI (10(-6) M) (antagonists of alpha7 nicotinic receptors). (+/-)-Epibatidine (3x10(-7) M) (a very potent, but non-selective agonist) and (-)-cytisine (3x10(-4) M) (an agonist of beta4 nicotinic receptors) effectively evoked the release of noradrenaline, while (E)-N-methyl-4-(3-pyridinyl)-3-butene-1-amine (RJR-2403) (up to 10(-4) M) (an agonist of alpha4beta2 nicotinic receptors) had no effect. The potency of these agonists was as followed; (+/-)-epibatidine>>(-)-nicotine>(-)-cytisine>>>RJR -2403. These results are compatible with the published view that alpha3beta4 nicotinic receptors are predominant in other parts of the autonomic nervous system. These receptors (probably located on the gastric sympathetic ganglia) are involved in the release of noradrenaline from the rat stomach.

Animals↗
PubMed2000

Pulmonary vascular disease in Down's syndrome with complete atrioventricular septal defect.

We sought to determine the predisposing factors of pulmonary vascular disease (PVD) in complete atrioventricular septal defect. Down's syndrome is considered a risk factor for PVD, but the progression of PVD differs in each case. Morphometric analysis in autopsied hearts showed that Rastelli type A morphology had a narrower left ventricular outlet and a wider right ventricular outlet than did type C. In 81 consecutive patients with Down's syndrome who underwent cardiac catheterization, we estimated the following variables: Rastelli subtypes, pulmonary vascular resistance, pulmonary-to-systemic flow ratio, patients' age, and operative outcome. The hemodynamic variables in those <1 year old did not differ between the groups with type A and type C. However, all 5 patients with fatal pulmonary hypertension in early infancy had type A morphology. The lung histology revealed that 3 of these patients already had irreversible PVD. At >/=1 year old, those with type A showed a significantly higher pulmonary vascular resistance (p <0.001) and a lower pulmonary to systemic flow ratio (p <0.05) than did those <1 year old. In contrast, neither of these variables in the type C group differed between those >/=1 and <1 year old. Moreover, those with type A had a greater risk of being contraindicated for surgical repair (p <0.05). We suspect, therefore, that type A morphology is an independent risk factor for PVD in those with Down's syndrome associated with this anomaly. This hemodynamic influence could become obvious once patients are >/=1 year old. It may also sometimes result in irreversible PVD even in early infancy.

Adolescent↗