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Biomedical subjects

K Yano

Publications and source records attributed to K Yano.

At least 397 records · Page 22Linked to original sources
PubMed1994

Effects of washing with a neutralizing agent on alkaline skin injuries in an experimental model.

In this report a skin alkaline injury model was constructed using experimental rats and 2 N NaOH. We observed the effects of washing with a neutralizing agent on the subcutaneous tissue pH at 1, 10 and 30 min after injury and compared it with water-washing groups. In comparison with the water washing group, the peak pH values following the use of the neutralizing agent were significantly higher in the 1-min washing group, and significantly lower in the 10-min and 30-min washing groups. Changes in the pH values of the subcutaneous tissue after reaching a peak showed a similar course in the 1-min washing group, whereas in the 10 and 30 min washing groups there was a significantly different rate of decrease of pH. These results indicate that although treatment with a neutralizing agent directly after injury causes harmful effects due to the neutralizing reaction with a highly concentrated alkali. Subsequently with prolonged washing there is an effective reduction of the high pH.

Animals↗
PubMed1994

A clinicopathological evaluation of nucleolar organizer region proteins in human breast carcinoma.

The number of nucleolar organizer region proteins (NORs) identified by silver staining (Ag) was studied in 106 primary breast carcinomas. The AgNOR score (mean +/- SD) in tumours smaller than 2 cm was significantly lower than that in tumours larger than 2 cm (P < 0.05). However, there was no significant difference according to other clinicopathological characteristics. According to postoperative distant recurrence, the AgNOR count was significantly higher in the group with recurrence than in the group without recurrence (P < 0.05). Further, the survival rate was significantly lower in the high AgNOR score (> or = 3) group than in the low score (< 3) group (P < 0.01). The present study indicates that the AgNOR score in human breast cancer cells is useful for evaluating cell proliferative activity and may help predict postoperative distant recurrence and, ultimately, the postoperative prognosis of patients.

Adult↗
PubMed1994

The extent and number of metastatic lymph nodes limit the efficacy of lymphadenectomy in patients with oesophageal carcinoma.

The extent and number of metastatic lymph nodes in 52 patients with oesophageal carcinoma involving more than one lymph node were analysed to determine the efficacy of lymphadenectomy. The patients were divided into two groups according to the number of metastatic lymph nodes, group A: 1-4 nodes (34 cases) and group B: 5 or more nodes (18 cases). The survival of all patients in group A was statistically better than that of the patients in group B (P = 0.02). In cases where metastatic nodes were restricted to one region, the survival of patients in group A was significantly better than that of patients in group B (P = 0.006). By contrast, in cases where metastatic nodes extended to two or more regions, there was no difference between the groups. The present study suggests that lymphadenectomy is effective only for patients with 1-4 metastatic nodes that are restricted to a single region. Lymphadenectomy is less efficacious in cases with five or more metastatic nodes, even when the nodes are restricted to one region, and is similarly ineffective in cases with metastatic nodes extending to two or more regions, regardless of the number of positive nodes.

Adult↗
PubMed1994

Incidence and electrophysiologic characteristics of supernormal atrial conduction in humans.

The incidence and electrophysiologic characteristics of supernormal atrial conduction (SNC) were examined by cardiac stimulation in 53 control subjects. Their ages ranged from 15 to 71 years (mean age, 50 +/- 21 years) (mean +/- SD). There were 27 women and 26 men in the study. Conduction of premature atrial responses from the sinus node to the atrioventricular node (intraatrial conduction time) was supernormal in 27 (51%) subjects and conduction to the left atrium (interatrial conduction time) was supernormal in 35 (66%) subjects (difference not significant). At coupling intervals ranging between 440 and 240 ms, the conduction time of the premature beats was as much as 25 ms shorter than that of the basic driven beats. The maximum decrease in interatrial conduction time during the period of SNC was 13 +/- 5 ms and the maximum decrease in intraatrial conduction time was 9 +/- 3 ms (P < .001). The supernormal interatrial conduction zone was 71 +/- 29 ms and the supernormal intraatrial conduction zone was 57 +/- 25 ms (P < .05). There was a significant positive correlation between the SNC zone and the maximum decrease in conduction time (r = .82; P < .001). Supernormal atrial conduction was stable, reproducible, and remained constant in individual patients. Supernormal atrial conduction was found to be a relatively frequent phenomenon. There was a significantly greater SNC zone and maximum decrease in conduction time in interartrial conduction than in intraatrial conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function↗
PubMed1994

Evidence of quadruple anterograde atrioventricular nodal pathways in a patient with atrioventricular node reentry.

Functional longitudinal dissociation of the atrioventricular (AV) node exhibiting two discrete discontinuities in AV nodal conduction curves suggestive of triple AV nodal pathways has been described. The authors report here unusual electrophysiologic properties of the AV node in a patient with documented episodes of paroxysmal supraventricular tachycardia. Programmed atrial extrastimuli introduced at A1-A2 coupling intervals of 390 ms with a driven cycle length of 500 ms produced a sudden marked increase of 75 ms at the A2-H2 intervals suggesting failure of the fast pathway with conduction proceeding through a slower pathway with a shorter refractory period. With further decreasing coupling intervals, a second sudden jump of 70 ms and a third one of 150 ms occurred at A1-A2 coupling intervals of 330 and 290 ms, respectively. Beyond the first sudden jump, atrial echoes occurred when sufficiently slow pathway delay permitted recovery of the fast pathway for retrograde conduction. The atrial echo zone was 170 ms. These electrophysiologic demonstrations of reentry within the AV node in a patient with clinically documented supraventricular tachycardia and the existence of four ranges of AH conduction times and refractory periods strongly suggest the presence of quadruple anterograde AV nodal pathways and a variety of potential loops available for the development of sustained AV nodal reentrant tachycardia.

Adult↗
PubMed1994

Repetitive atrial firing and fragmented atrial activity elicited by extrastimuli in the sick sinus syndrome with and without abnormal atrial electrograms.

Endocardial catheter mapping of the right atrium during sinus rhythm and programmed atrial stimulation were performed in 50 patients with sick sinus syndrome to investigate the relationship between abnormal atrial electrograms recorded during sinus rhythm and some determinants of the atrial vulnerability such as repetitive atrial firing and fragmented atrial activity elicited by single extrastimulus. The patients were divided into 2 groups on the basis of the presence (Group I) or absence (Group II) of abnormal atrial electrograms recorded during sinus rhythm. In Group I (N = 32), repetitive atrial firing was induced in 23 (72%) patients, and in Group II (N = 18) in 6 (33%) patients; p less than 0.01. The repetitive atrial firing zone was 41 +/- 37 ms in Group I and 12 +/- 18 ms in Group II; p less than 0.001. Fragmented atrial activity was induced in 30 (94%) patients from Group I, and in 8 (44%) patients from Group II; p less than 0.0001. The fragmented atrial activity zone was 47 +/- 42 ms in Group I and 14 +/- 19 ms in Group II; p less than 0.0001. The atrial electrogram width at the premature beat (A2; p < 0.02) and the maximum A2/A1 ratio (p < 0.002) were 178 +/- 53 ms and 196% +/- 40%, respectively in Group I, and 141 +/- 36 ms and 159% +/- 30%, respectively in Group II. Atrial fibrillation was induced in 13 (41%) patients from Group I, and in 1 (6%) patient from Group II (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Comparative study of auricular dimensions for the normal auricles of microtia patients, their parents, and normal individuals.

We measured the dimensions of the normal auricle in microtia patients and those of both auricles in their parents, and compared the findings with data obtained in normal individuals. The physiognomical auricular length and width dimensions of the normal auricles in microtia patients were significantly smaller than those in normal individuals. The auricular length of the parents of microtia patients was also significantly smaller than in normal individuals. The auricles of the parents on the same side as those affected by microtia in the patients tended to be smaller than those on the contralateral side.

Adolescent↗
PubMed1994

Time limits for intestinal ischemia and congestion: an experimental study in rats.

We investigated to determine the time limits for intestinal ischemia and congestion. The experimental models were produced by clamping both ends and the intended feeder vessels of an approximately 1-cm length of rat jejunum. The results showed that in arteriovenous occlusion, the time required for the recovery rate to reach 50% was 7.03 hours. The time required for the recovery rate to reach 50% was 6.81 hours when arterial occlusion alone was performed and 3.70 hours when venous occlusion alone was performed. The difference between the two was statistically significant (p < 0.01). Consequently, it was found that the degree of intestinal damage due to venous occlusion was greater than the damage resulting from arteriovenous and arterial occlusion.

Animals↗
PubMed1994

Morphometric characteristics of cryptotia.

In this study, we measured the normal and affected auricles of patients with cryptotia by the Martin method, quantitatively analyzed the data, and conducted a comparative study. On the basis of auricular measurements, cryptotia is defined as a deformity of the upper one third of the auricle, which develops as a result of the sum total of vectors operating inferiorly and medially. Furthermore, these data showed that the deformity occurring along the vertical axis is greater and that the inferiorly directed vector is stronger than the medially directed vector. A helical adhesion-like deformity was observed in the normal side auricles of 3 patients with unilateral cryptotia, and the hypothesis that the upper portion of the auricle became embedded secondary to a deformity of the cartilage appeared to be valid.

Child↗
PubMed1994

Intestinal tissue pH monitoring in microsurgery: an experimental study in rats.

We monitored the pH of ischemic intestine in rats to determine whether such measurements were a useful method of postoperative monitoring. Measurement of intestinal pH was found to be useful in detecting vascular occlusion, in distinguishing arterial from venous occlusion, and in estimating the time of occlusion. This method of monitoring can be recommended after free intestinal grafting.

Animals↗
PubMed1994

Effects of intrahepatic arterial and intraportal administration of FK 506 on liver allograft survival in rats.

Rejection is still the limiting factor for successful organ transplantation, and overdosage of immunosuppressive drugs often results in severe viral infection, side-effects and toxicity. Thus, more specific immunosuppression to lessen these side-effects is highly desirable. In this study, we compared the effects of FK 506 administered by different routes (hepatic artery, portal vein and systemic circulation) on the inhibition of rejection. FK 506 was given to recipient LEW rats with PVG liver grafts via the penile vein (systemic administration), portal vein or hepatic artery (local administration) for 3 or 7 successive days after liver transplantation. In control LEW rats without immunosuppression, the PVG liver allografts were rejected between 9 and 21 days after transplantation. Intravenous administration of FK 506 for 3 days (0.32 and 1.28 mg/kg daily) only had a marginal effect on prolonging liver allograft survival (21.1 +/- 12.5 and 32.0 +/- 24.0 days, respectively; control 14.1 +/- 4.1 days). However, systemic administration of FK 506 (0.08-1.28 mg/kg daily) for 7 days suppressed liver allograft rejection markedly (42.3 +/- 5.9 to 80.5 +/- 53.4 days; control 14.1 +/- 4.1 days), and 50% of the recipient rats survived for at least 60 days after liver transplantation. Moreover, when a low dose of FK 506 (0.32 mg/kg) was infused into the hepatic artery or portal vein of the transplanted liver for 3 days only, liver allograft survival times were prolonged markedly, and 54% of rats with grafts survived for at least 60 days. This effect was almost equal to that after 7 days systemic treatment with FK 506. In conclusion, 7 days' treatment with FK 506 administered systemically was an effective regimen for the suppression of liver allograft rejection in rats. Furthermore, local immunosuppression with low-dose, short-term (3 days) FK 506 treatment administered via the hepatic artery or portal vein of the transplanted liver dramatically improved allograft salvage.

Animals↗
PubMed1994

Cloning and sequencing of a 2,5-dichloro-2,5-cyclohexadiene-1,4-diol dehydrogenase gene involved in the degradation of gamma-hexachlorocyclohexane in Pseudomonas paucimobilis.

In Pseudomonas paucimobilis UT26, gamma-hexachlorocyclohexane (gamma-HCH) is converted to 2,5-dichloro-2,5-cyclohexadiene-1,4-diol (2,5-DDOL), which is then metabolized to 2,5-dichlorohydroquinone. Here, we isolated from the genomic library of UT26 two genes which expressed 2,5-DDOL dehydrogenase activity when they were transformed into P. putida and Escherichia coli. Both gene products had an apparent molecular size of 28 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The first gene, named linC, located separately from the two genes (linA and linB) which we had already cloned as genes involved in the gamma-HCH degradation. The other, named linX, located about 1 kb upstream of the linA gene encoding gamma-HCH dehydrochlorinase. A gamma-HCH degradation-negative mutant, named UT72, which lacked the whole linC gene but had the intact linX gene was isolated. The linC gene given in a plasmid could complement UT72. These results strongly suggest that the linC gene but not the linX gene is essential for the assimilation of gamma-HCH in UT26. Deduced amino acid sequences of LinC and LinX show homology to those of members of the short-chain alcohol dehydrogenase family.

Alcohol Oxidoreductases↗
PubMed1994

Identification of the bphA4 gene encoding ferredoxin reductase involved in biphenyl and polychlorinated biphenyl degradation in Pseudomonas sp. strain KKS102.

The nucleotide sequence of the downstream region of the bph operon from Pseudomonas sp. strain KKS102 was determined. Two open reading frames (ORF1 and ORF2) were found in this region, and the deduced amino acid sequence of ORF2 showed homology with the sequences of four ferredoxin reductases of dioxygenase systems. When this region was inserted just upstream of the bph operon, which does not contain a gene encoding ferredoxin reductase, biphenyl dioxygenase activity was detected. The 24- and 44-kDa polypeptides predicted from the two open reading frames were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Crude extract which contained the products of ORF2 and bphA1A2A3 showed cytochrome c reduction activity. These data clearly suggest that ORF2 encodes ferredoxin reductase. The deduced amino acid sequence of ORF1 does not show significant homology with the sequences of any other proteins in the SWISS-PROT data bank, and the function of ORF1 is unknown.

Amino Acid Sequence↗
PubMed1994

Chronic hyperinsulinemia augments deoxycorticosterone acetate-salt hypertension.

To evaluate the effect of chronic hyperinsulinemia on blood pressure in salt-dependent hypertension, we infused insulin (1.0 IU/d, n = 15) or saline (n = 13) for 4 weeks into deoxycorticosterone acetate-salt hypertensive rats. The insulin infusion increased plasma insulin levels to 24 +/- 2 microU/mL, which was higher than in the saline-infused rats (9 +/- 1 microU/mL) but was still within the physiological range. Blood pressure was measured by the tail-cuff method twice a week, and daily sodium intake and urinary sodium excretion were calculated for 3 weeks. At week 4, arterial pressor responsiveness to norepinephrine, angiotensin II, and hexamethonium bromide was evaluated. After 14 days of chronic infusion, the insulin group showed a higher blood pressure than the saline group (on 21st day: 178 +/- 6 versus 156 +/- 5 mm Hg, P < .05 by tail-cuff method; 171 +/- 4 versus 149 +/- 3 mm Hg, P < .05 by direct intra-arterial measurement). This blood pressure difference was eliminated after ganglionic blockade with hexamethonium bromide (86 +/- 4 mm Hg in insulin-treated and 89 +/- 4 mm Hg in saline-treated rats by direct intra-arterial measurement). Throughout the experiment, neither sodium balance nor arterial pressor responsiveness to norepinephrine or angiotensin II differed between the two groups. In conclusion, chronic hyperinsulinemia in the physiological range augments the development of hypertension in salt-dependent hypertension, and this augmentation may be mediated by sympathetic stimulation independent of salt retention.

Analysis of Variance↗
PubMed1994

Involvement of Na(+)-H+ antiporter in regulation of L-type Ca2+ channel current by angiotensin II in rabbit ventricular myocytes.

The present study investigated the possible involvement of a Na(+)-H+ antiporter in the regulation of L-type Ca2+ channels by angiotensin II (Ang II) in isolated rabbit ventricular cardiac myocytes by using both cell-attached and whole-cell patch-clamp current recording techniques. In cell-attached patch-clamp current recordings, an increase in the open-state probability of the Ca2+ channel (144.8 +/- 9.8% [mean +/- SEM], n = 11) was seen after exposure of the cells to Ang II (100 nmol/L). This effect was inhibited by pretreatment with losartan (10 mumol/L), a synthetic antagonist of the AT1 receptor. 5(N,N-Dimethyl)amiloride (100 mumol/L), an amiloride analogue, as well as Na(+)-deficient bath solution abolished Ang II-induced stimulation of the Ca2+ channel activities. In whole-cell patch-clamp current recordings, Ang II also increased the L-type Ca2+ current when a pipette solution of pH 7.1 containing 5 mmol/L HEPES (139 +/- 5%, n = 4) was used but did not significantly increase the current when a pipette solution of pH 7.5 containing 5 mmol/L HEPES or a pipette solution of pH 7.1 containing 30 mmol/L HEPES was used. These results suggest that Ang II-induced stimulation of the Ca2+ channels is mediated by a Na(+)-H+ antiporter and therefore provide a novel insight into signal transduction of Ang II receptor stimulation in cardiac myocytes.

Angiotensin II↗
PubMed1994

Body mass index and thromboembolic stroke in nonsmoking men in older middle age. The Honolulu Heart Program.

BACKGROUND AND PURPOSE: While evidence suggests that obesity has an independent relation to coronary artery disease, similar findings for stroke have not been established. The purpose of this study was to examine the relation between body mass index and the risk of thromboembolic stroke independently of other risk factors. METHODS: Since 1965, the Honolulu Heart Program has followed a cohort of men in a prospective study of cardiovascular disease. This article examines the relationship between the baseline measurement of body mass index and the risk of thromboembolic stroke in 1163 nonsmoking men in older middle age (55 to 68 years). Men who had an elevated risk of stroke due to hypertension, diabetes, and other risk factors were excluded from the analysis. RESULTS: After 22 years of follow-up, the rate of stroke increased significantly with increasing levels of body mass (P < .01). In the bottom tertile of the body mass index, the rate of thromboembolic stroke was 28.7 per 1000 (11/383). In the middle tertile, the rate was increased by 40% to 40.7 per 1000 (16/393), and in the top tertile, the rate of thromboembolic stroke was 55.4 per 1000 (21/387), a twofold excess compared with the bottom tertile. After adjustment for age and the residual effects of confounding risk factors, including systolic blood pressure and serum glucose, the estimated relative risk of stroke for the average body mass index in the top tertile (26.6 kg/m2) compared with that in the bottom tertile (20.3 kg/m2) was 2.1 (95% confidence interval, 1.1 to 4.1). These findings were not affected by coronary events that occurred in the course of follow-up, nor did they appear to be influenced by deaths from other causes. CONCLUSIONS: We conclude that elevated body mass is associated with an increased risk of thromboembolic stroke in nonsmoking men in older middle age who are free of commonly observed conditions related to cardiovascular disease.

Age Factors↗
PubMed1994

Elevated serum cholesterol is a risk factor for both coronary heart disease and thromboembolic stroke in Hawaiian Japanese men. Implications of shared risk.

BACKGROUND AND PURPOSE: The relation between total serum cholesterol level and thromboembolic or nonhemorrhagic stroke is controversial. The Honolulu Heart Program cohort of Japanese-American men provides data which show that elevated serum cholesterol is an independent predictor of thromboembolic stroke as well as coronary heart disease (CHD). The data are presented to suggest that the association of elevated cholesterol with stroke is sometimes underestimated or underreported partly because of competing or shared risk with CHD, the other major atherosclerotic end point. METHODS: The data are based on 6352 men (aged 51 to 74 years) at baseline examination (1971 to 1974) who were free of clinical CHD and stroke and were followed an average of 15 years for new cases of both end points. Relative risks of serum cholesterol for CHD and thromboembolic stroke were calculated, controlling for other major cardiovascular covariates. RESULTS: There was a continuous and progressive increase in both CHD and thromboembolic stroke rates with increasing levels of serum cholesterol. The relative risk between the highest and lowest quartiles of serum cholesterol was 1.7 (95% confidence interval, 1.4 to 2.0) for CHD and 1.4 (95% confidence interval, 1.1 to 1.9) for thromboembolic stroke. There was a decline in the difference in relative risks between CHD and thromboembolic stroke in older men (aged 60 years and older) compared with younger men (aged younger than 60 years). CONCLUSIONS: These data provide additional evidence that elevated serum cholesterol should be considered a primary risk factor for thromboembolic stroke, presumably through its effect on both coronary and cerebrovascular atherosclerosis. It is suggested that this association is sometimes underestimated or underreported partly because of shared or competing risk with CHD, the clinical manifestation of atherosclerosis that generally occurs earlier in life and with greater frequency than thromboembolic stroke.

Aged↗