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Biomedical subjects

Y Kato

Publications and source records attributed to Y Kato.

At least 163 records · Page 9Linked to original sources
PubMed2001

Treatment of unruptured intracranial aneurysms--a clinicopathological correlation.

OBJECT: Brain check-up is very important for detecting the incidence and prevalence of aneurysms in the population and to get the definite strategy for the treatment of intracranial aneurysms. METHODS: This is a retrospective study of 116 aneurysms detected by brain check-up between 1998-1999 which were treated either by clipping or endovascular coiling. In some cases the aneurysmal wall was resected for histopathological examination and compared with five normal autopsy cases. CONCLUSIONS: Direct surgery is the primary option for a patient with an aneurysm in the anterior circulation especially in young patients. Intravascular therapy is suitable for aneurysms in the posterior circulation and in intracavernous site.

Aged↗
PubMed2001

Monitoring of facial evoked EMG for hemifacial spasm: a critical analysis of its prognostic value.

Microvascular decompression (MVD) has come to stay as an effective way of treating hemifacial spasm. But it remains to be seen how much each of the electrophysiological monitoring techniques (intra-operative) are contributing to its increased efficacy. Their role as indicators for re-exploration or recurrence is to be evaluated with more studies. We have used the lateral spread response in those patients who had distinctly abnormal recording on the ipsilateral side, studied the intra-operative changes during MVD and correlated with the outcome of surgery. 38 patients operated for HFS, were selected for intra-operative monitoring of abnormal muscle responses. In 17 patients, there was persistence of abnormal muscle responses in the immediate postoperative period and only 6 of them had mild HFS. Two of 21 patients who had disappearance of abnormal responses had persistent mild HFS; but in all cases, the HFS disappeared within 3 months. So we found that the intra-operative recording was really not reliable in predicting the immediate postoperative outcome. However the outcome at 3 months suggested that waiting for some time before re-exploration is a better option, especially if the HFS had become mild.

Adult↗
PubMed2001

Can 3D-CTA surpass DSA in diagnosis of cerebral aneurysm?

After introducing of Helical scanning CT (HCT) and 3D-CTA (three-dimensional CT angiography), various improvements to these methods have been made every year to achieve better imaging quality. The current resolution permits visualisation of the internal structure of tumors, although as yet insufficiently clearly. We suggest that these improvements can be more efficient than conventional cerebral aneurysms angiography. In this study, we compared HCT and 3D-CTA with conventional cerebral angiography in patients with cerebral aneurysms at our facility. We also examined whether 3D-CTA has the possibility of independent clinical application and can surpass conventional DSA in diagnostic efficacy. In this paper, we found this information insufficient in clipping operations using 3D-CTA only when 1) It was difficult to distinguish a crooked infundibular dilation from an aneurysm, 2) Imaging threshold influenced the measured value of the vascular diameter and 3) It was also difficult to confirm whether the peripheral vessels adhere to the aneurysm. In conclusion, from the result of the comparison between 3D-CTA and DSA in this study, it was concluded that 3D-CTA is a reliable alternative method to conventional angiography in the diagnosis of anterior circulation and most aneurysms of regular size. In such cases it may be possible to obtain the same quality of preoperative information, but it is less invasive.

Adult↗
PubMed2001

Implantation of rectal cancer cells in a fistula in ano: report of a case.

We report a case of implantation of tumor cells within a fistula in ano. A 36-year-old man with a 16-year history of an anal fistula underwent an operation for rectal carcinoma. Three weeks later, the anal fistula was resected. A histological examination of the specimen showed atypical cells; moreover, rectal carcinoma had proliferated in the granulation tissue lying underneath the intact squamous epithelium. Because there was no continuity to the rectal carcinoma or the anal glands, we diagnosed implantation of rectal cancer cells in a fistula in ano.

Adenocarcinoma↗
PubMed2001

A new procedure for chronic atrial fibrillation: bilateral appendage-preserving maze procedure.

BACKGROUND: Atrial transport and atrial natriuretic peptide secretion is severely reduced from normal after the maze III procedure. To improve these factors, we developed a bilateral appendage-preserving maze procedure (BAP-maze). METHODS: Forty-six patients with chronic atrial fibrillation who underwent the BAP-maze procedure were compared with 40 patients who underwent the maze III procedure. The ratio of the peak velocity of the A and E waves of transmitral flow (transthoracic pulsed Doppler echocardiography), the left atrial appendage ejection fraction (transesophageal echocardiography), and the atrial natriuretic peptide secretory reserve during treadmill exercise test were measured at 6 months postoperatively. RESULTS: Sinus rhythm was restored in 44 patients (95.7%) by the BAP-maze procedure and in 39 patients (97.5%) by the maze III procedure. The ratio of the peak velocity of the A and E waves was 0.52 +/- 0.22 in the BAP-maze group and 0.25 +/- 0.19 in the maze III group (p < 0.0001). The left atrial appendage ejection fraction was 44.7% +/- 11.5%, and the atrial natriuretic peptide secretory reserve was greater in the BAP maze group (p = 0.037). CONCLUSIONS: The BAP-maze procedure improved atrial transport and atrial natriuretic peptide secretion as well as simplifying the maze operation, without decreasing its effectiveness against atrial fibrillation.

Aged↗
PubMed2001

Expression and localization of MGP in rat tooth cementum.

Tooth cementum, a calcified hard tissue covering the root surfaces, is an important component connecting the teeth to the collagenous fibres of the periodontal ligament. Although the overall composition of cementum may closely resemble that of bone, each part has not been fully characterized. Here, the localization of the matrix gamma-carboxyglutamic acid (Gla) protein (MGP), one of the major Gla-containing proteins in the body, in cementum was investigated using immunohistochemistry and in situ hybridization. (1) Strong MGP antigenicity was observed in the acellular cementum, but was only moderate in the cellular cementum; (2) polygonal periodontal ligament cells facing the acellular cementum and the uncalcified cellular cementum expressed MGP mRNA, indicating that these cells produced MGP and deposited it on the cementum; (3) MGP accumulated at the junction between the uncalcified and calcified cellular cementum; and (4) the distribution pattern of MGP antigenicity resembled that of osteopontin. As one function of MGP could be as a negative regulator for mineral apposition, the expression of MGP in the cells adjacent to the cementum may be important to prevent hyperapposition of minerals.

Animals↗
PubMed2001

Insulin mimetic effect of a tungstate cluster. Effect of oral administration of homo-polyoxotungstates and vanadium-substituted polyoxotungstates on blood glucose level of STZ mice.

Aqueous vanadate and aqueous tungstate have been known to mimic all or most of the actions of insulin in intact cell systems with respect to normalization of the blood glucose level. By carrying out oral administration in vivo experiments on the blood glucose level of streptozotocin (STZ)-induced diabetes (STZ mice), the insulin-mimetic (IM) effects of metal-oxide clusters of all-inorganic composition were examined using many types of polyoxometalates (POM) with and without vanadium substitution. Several homo-POM and vanadium-substituted POM showed hypoglycemic effects. The observed hypoglycemic effects indicated that POM with the Dawson structure [[alpha-P(2)W(18)O(62)](6-) (W-2), [alpha-P(2)W(17)V(V)O(62)](7-) (V-19) and [alpha-1,2,3-P(2)W(15)V(V)(3)O(62)](9-) (V-04)] are more effective than those with the Keggin structure [[alpha-PW(12)O(40)](3-) (W-1), [alpha-PW(11)V(V)O(40)](4-) (V-01), [alpha-1,2-PW(10)V(V)(2)O(40)](5-) (V-02), [alpha-1,2,3-PW(9)V(V)(3)O(40)](6-) (V-03) and [alpha-1,4,9-PW(9)V(V)(3)O(40)](6-) (V-13)]. The vanadate cluster [V(10)O(28)](6-) (V-15) also showed a hypoglycemic effect. (31)P and (51)V NMR measurements showed that the Dawson POM (W-2, V-04 and V-19) are stable in aqueous solution under the conditions used. The effect of all POM on the body weight of STZ mice was also examined. The decrease in body weight after administration of W-2 was much less than for V-19, V-04 and V-15. This suggests that not only monomeric tungstate and vanadate, but also the structure factors of tungstate and vanadate clusters, can play a significant role in their biological action.

Administration, Oral↗
PubMed2001

Habituation of the early pain-specific respiratory response in sustained pain.

Neurokinin-1 receptor and mu-opioid receptor agonists affect respiratory rhythm when injected directly into the preBötzinger brainstem complex, which is the hypothesized site for respiratory rhythmogenesis in mammals (Science 286 (1999) 1566). Early stress-induced analgesia (SIA) is naloxone-insensitive and as such considered independent of the activation of the mu-opioid system. Prolonged application of electrical shocks, however, produces analgesia that is mediated by the mu-opioid system (Science 208 (1980) 623). Together these findings suggest that any early pain-specific increased respiration should be attenuated in the tonic state of pain. Ten healthy, pain-free female volunteer subjects participated in this experimental study involving deep acute and tonic pain. The experimental design included three conditions: (1) baseline; (2) pain; and (3) a placebo control stimulus. Experimental pain was induced by the infusion of hypertonic saline into the masseter muscle. Infusion of isotonic saline in the contralateral masseter was used as a control. Blinded subjects were randomly assigned to a particular sequential order of the experimental stages, i.e. hypertonic saline infusion preceded the isotonic saline infusion or vice versa. Respiration rate, mean peak inspiratory and expiratory flow rates, and the minute ventilation volume quantified breathing. Results indicate that effects on respiration were pain-specific and that the early effects on respiration were significantly attenuated in sustained pain. In the early stage of pain, all monitored variables (respiration rate, minute ventilation volume, and inspiratory and expiratory flow rates) were elevated to statistically significant degrees when compared to measurements taken at baseline or during control infusion. Only respiration rate continued to be significantly elevated in sustained pain. We concluded that rhythmogenic neurons in the preBötzinger brainstem complex appear as the likely target for pro-nociceptive and anti-nociceptive input, explaining both the observed initial facilitation and subsequent habituation of respiration in early and sustained pain.

Adult↗
PubMed2001

Significance of the eosinophil cationic protein/eosinophil count ratio in asthmatic patients: its relationship to disease severity.

BACKGROUND: Serum levels of eosinophil cationic protein (ECP) may reflect the degree of bronchial inflammation in patients with asthma, but its clinical value as a parameter for monitoring asthma remains controversial. OBJECTIVE: We measured the ratios of the serum ECP concentrations to peripheral blood eosinophil counts (ECP/Eo ratio) in patients with asthma and evaluated the correlation between these ratios and individual asthma severity. METHODS: The serum ECP concentrations and peripheral blood eosinophil counts were measured by radioimmunoassay and an autoanalyzer, respectively. Each patient with asthma was in remission at the time the serum specimen was obtained. An overall evaluation of asthma severity for each patient was determined by the frequency and severity of asthma attacks and by clinical scores. RESULTS: The ECP/Eo ratio in patients with severe asthma was significantly higher than in those with mild asthma. However, serum ECP concentrations and peripheral blood eosinophil counts were not different among the patients with mild, moderate, or severe asthma. The ECP/Eo ratios correlated significantly with the monthly average of the clinical scores, but the serum ECP concentrations did not correlate with the monthly average of the clinical scores. The ECP/Eo ratios were also increased in patients with more severe asthma whose serum IgE concentrations and peripheral eosinophil counts were not elevated. CONCLUSIONS: The ECP/Eo ratio may be useful in assessing asthma severity; however, the serum ECP concentration or peripheral blood eosinophil count is not useful.

Adolescent↗
PubMed2001

Performance of a shaking vessel with current pole.

To improve solid particle suspensions in liquids in a shaking vessel, a pole was installed at the axis of the shaking vessel, which was referred to as the "current pole". The performance of a shaking vessel with current pole at its central axis was examined experimentally with respect to particle dispersion, power consumption, mixing time and solid-liquid mass transfer coefficient. The current pole improved the particle suspension without an increase in power consumption and reduced the critical circulating frequency for complete suspension. The current pole was very effective in eliminating the stagnation point on the vessel bottom and to decrease the mixing time. The mass transfer coefficient with a current pole had the same value as that without a current pole above the critical circulating frequency for complete suspension. As the diameter of the current pole increased, the mixing time decreased. A pole diameter of 5% of the vessel diameter was effective for suspension.

Journal Article↗
PubMed2001

Effects of FK506 and other immunosuppressive anti-rheumatic agents on T cell activation mediated IL-6 and IgM production in vitro.

The objective of this study was to investigate the therapeutic potential of FK506 and other immunosuppressive agents for the treatment of rheumatoid arthritis (RA), focusing on the effects on in vitro IL-6 production and IL-6-mediated immune response. We employed an in vitro model producing IL-6 via T cell activation in human PBMC, based on the hypothesis that T cells play a central role in the pathogenesis of RA. FK506 potently inhibited IL-6 production from PBMC stimulated with anti-CD3 and anti-CD28 monoclonal antibody (anti-CD3/CD28). Cyclosporin A (CsA) also inhibited the anti-CD3/CD28 induced IL-6 production but was about 100 times less potent than FK506. Dexamethasone (DEX) inhibited both anti-CD3/CD28 and LPS induced IL-6 production at almost the same concentration. Methotrexate (MTX) did not affect cytokine production. Anti-CD3/CD28 stimulated PBMC culture supernatants were found to enhance IgM production in SKW6.4 cells. The effects of anti-CD3/CD28 stimulated culture supernatants in the presence of agents on IgM production in SKW6.4 cells were investigated. FK506 and CsA led to suppression of IgM production induced by culture supernatants probably via inhibition of IgM inducible cytokine production from PBMC. DEX profoundly enhanced IgM production, although IL-6 production from PBMC was strongly inhibited by the agent. MTX decreased IgM production although it has no inhibitory effect on IL-6 production. The present study suggests that FK506 is the most effective among the four agents for the suppression of IL-6 production and IL-6-mediated autoantibody production in T cell activation related autoimmune diseases such as RA.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

Comparison of heat-treated and tetraploid blastocysts for the production of completely ES-cell-derived mice.

The present study compared the production efficiency and incidence of postnatal death in mice derived by injecting embryonic stem (ES) cells into either heat-treated blastocysts or tetraploid blastocysts. The proportion of completely ES-cell-derived mice from the tetraploid blastocyst group (3.3%) was significantly higher than that obtained from the heat-treated blastocyst group (1.5%). The incidence of postnatal death was the same between the two groups: 10 of 15 young (67%) in the heat-treated group and 21 of 34 young (62%) in the tetraploid group died within 13 days of birth. The remaining young grew to adulthood, had normal fertility, and their germ cells were of ES cell origin. There was no clear correlation, however, between the postnatal lethality of ES-cell-derived mice and the genetic background of the ES cells. The causes of postnatal death are discussed.

Aging↗
PubMed2001

Antioxidative properties of phenolic antioxidants isolated from corn steep liquor.

With the immersion of corn into dilute sulfur oxide during starch-manufacturing processes, corn steep liquor (CSL) remains as leftover material. CSL is often used for fermentation, but its components are not fully understood. To determine the properties of CSL, 12 p-coumaric acid-related compounds were isolated from an ethyl acetate extract of CSL with the guidance of antioxidative activity on the rabbit erythrocyte membrane ghost system. The activity of these compounds was compared against oxidative damages, and it was elucidated that the activity of p-coumaric acid derivatives was mainly affected by their functional groups at the 3-position and less by the conjugated side chain. Moreover, p-coumaric acid derivatives exhibited inhibitory activity stronger than that of tocopherols and ascorbic acid on peroxynitrite-mediated lipoprotein nitration. These findings that p-coumaric acid derivatives, which might play a beneficial role against oxidative damage, exist in CSL suggest this byproduct might be a useful resource of phenolic antioxidants.

Acetates↗
PubMed2001

Practical synthesis of 3-methylnonane-2,4-dione, an intense strawlike and fruity flavored compound.

A practical synthesis of 3-methylnonane-2,4-dione, which is an intense strawlike and fruity flavored compound, has been performed by the aldol condensation of n-hexanal and methyl ethyl ketone, followed by oxidation using sodium hypochlorite in the presence of 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxide in an overall yield of 59%. The purification of 3-methylnonane-2,4-dione with high purity was performed via copper complexes.

Aldehydes↗
PubMed2001

Decrease in antigenic and allergenic potentials of ovomucoid by heating in the presence of wheat flour: dependence on wheat variety and intermolecular disulfide bridges.

The antigenic and allergenic activities of ovomucoid (OM) remaining in soluble fractions of pasta-like model samples of wheat flour mixed with egg white were investigated by ELISA competitive inhibition and immunoblotting analyses using a rabbit anti-OM IgG and the serum IgE specific for OM in patients allergic to egg white. The mixture of egg white and wheat flour of soft, hard, and durum varieties was kneaded for 10-50 min and benched for 1 h at RT, and then small pieces of the dough were heated in boiling 1% NaCl solution for 15 min. Even before heating, only after the kneading for 30 min or more, but not after kneading for only 20 min, followed by the benching, the antigenic activity of OM which remained in the phosphate-buffered saline extract from the dough markedly decreased. Almost no antigenic activity of OM was detected in the extracts of heated samples. Furthermore, in the extracts of heated durum samples, only a trace of or almost no IgE-reactive OM was detected against the five patients' sera. These reductive effects of wheat on the OM antigenicity and allergenicity were more remarkable in the durum variety than in the others. No detectable proteins were extracted with 1% SDS from the heated samples, whereas OM was extracted with 1% SDS containing 10% 2-mercaptoethanol, suggesting heat-induced polymerization through intermolecular disulfide bonds among OM and wheat.

Allergens↗
PubMed2001

A long-term follow-up analysis of serial core promoter and precore sequences in Japanese patients chronically infected by hepatitis B virus.

To investigate the association of hepatitis B virus (HBV) with core promoter mutation (T1762A1764) or precore mutation (A1896) with the clinical course of illness, we analyzed serial core promoter and precore sequences in 22 patients with HBV-associated chronic liver disease who were followed for 12+/-4 years (mean +/- SD). Sixteen of 22 patients were positive for HBeAg at baseline, and 15 of the 16 patients seroconverted to anti-HBe during the observation period. T1762A1764 mutation was detected in 16 of 22 patients, including 11 patients positive for HBeAg, at baseline. During the follow-up period, A1896 mutation emerged in 7 of 16 patients who had the wild-type HBV or only the T1762A1764 mutation at baseline. Sustained remission of hepatitis correlated with the low level of viremia, but did not with type of mutations. These results indicate that HBV with T1762A1764 mutation tends to precede A1896 mutation during the course of infection in Japanese patients with chronic liver disease.

Adult↗
PubMed2001

Expression of endothelial nitric oxide synthase in the porcine oocyte and its possible function.

The present study was designed to investigate the localization of endothelial nitric oxide synthase (eNOS) in porcine oocytes and its possible function during in vitro development. RT-PCR and immunoblotting analyses revealed the presence of eNOS in the oocytes prepared from small follicles, with an amplified product of 456 bp and an apparent mol wt of 130 kDa, respectively. The synthesis of oocyte NO was suppressed during a 72-h culture of cumulus-oocyte complexes in the presence of follicle-stimulating hormone (FSH), but not luteinizing hormone (LH). However, the decrease in NO synthesis did not result from the levels of eNOS mRNA and its protein, as revealed by analyses of RT-PCR and Western blot analysis, suggesting that expression of oocyte eNOS is not dependent upon gonadotropin stimulation. In proliferated cumulus cells, LH receptor mRNA expression was detected after a 48-h culture with FSH, as revealed by RT-PCR analysis. mRNA expression was inhibited by an NO-releasing agent (S-nitroso-N-acetyl-DL-penicillamine) after an additional 24-h culture. These results suggest that oocytes may release eNOS-derived NO as a signal for somatic cells to steadily suppress the development of cumulus cells, if not FSH stimulation. Conversely, the synthesis of NO is suppressed during the action of FSH on the cumulus cells with no changes in eNOS expression.

Animals↗