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Biomedical subjects

Y Naito

Publications and source records attributed to Y Naito.

At least 163 records · Page 9Linked to original sources
PubMed1999

Ginkgo biloba leaf extract: review of biological actions and clinical applications.

The number of studies on Ginkgo biloba leaves is rapidly increasing. A variety of effects of Ginkgo biloba leaf extract (GBLE) have been identified. GBLE contains many different flavone glycosides and terpenoides. GBLE has an antioxidant action as a free radical scavenger, a relaxing effect on vascular walls, an antagonistic action on platelet-activating factor, an improving effect on blood flow or microcirculation, and a stimulating effect on neurotransmitters. Besides a direct scavenging action on active oxygen species, GBLE exerts an anti-inflammatory effect on inflammatory cells by suppressing the production of active oxygen and nitrogen species. GBLE inhibited the increase in the products of the oxidative decomposition low-density lipoprotein (LDL), reduced the cell death in various types of neuropathy, and prevented the oxidative damage to mitochondria, suggesting that GBLE exhibits beneficial effects on neuron degenerative diseases by preventing chronic oxidative damage. The study using a model of ischemia-reperfusion injury has also demonstrated the protective effect of GBLE on cardiac muscle and its antioxidative action in vivo. Favorable results have been obtained in double-blind, placebo-controlled, comparative trials of patients with memory disorders, obstructive arteriosclerosis, and dementia. We review the recent studies on GBLE with respect to its various pharmacological actions, such as a scavenging activity on free radicals and an inhibitory action on lipid peroxidation. GBLE shows a very strong scavenging action on free radicals, and is thus considered to be useful for the treatment of diseases related to the production of free radicals, such as ischemic heart disease, cerebral infarction, chronic inflammation, and aging.

Animals↗
PubMed1999

A novel water-soluble vitamin E derivative protects against experimental colitis in rats.

This study was designed to investigate the effects of water-soluble vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), on experimental colitis in rats. Colitis was induced in male Wistar rats weighing 200 grams using an enema of trinitrobenzene sulfonic acid (TNBS) dissolved in 50% ethanol; 1 ml of TMG dissolved in physiological saline (0.2 mg/ml, 2 mg/ml, 20 mg/ml) was injected intraperitoneally every day for 1 week after the enema. The damage score, wet weight of the colon, and increase in body weight were estimated 1 week after the enema of TNBS. Thiobarbituric acid-reactive substances (TBA-RS), an index of lipid peroxidation, and the level of alpha-tocopherol or TMG in the colonic mucosa were measured 1 week after the induction of colitis. As a result, increase in body weight was inhibited by the induction of colitis, although the inhibition was reduced in the group treated with TMG. The damage score, wet weight and TBA-RS were increased significantly in the colitis group; however, they were inhibited by the administration of TMG. The alpha-tocopherol level in the colonic mucosa was reduced by the induction of colitis, wheres TMG could not be detected in the colonic mucosa of rats treated with TMG. These results suggest that TMG is effective for the treatment of colitis in rats induced by TNBS.

Animals↗
PubMed1999

Growth inhibition of A549 human lung adenocarcinoma cells by L-canavanine is associated with p21/WAF1 induction.

L-Canavanine (CAV) is a higher plant nonprotein amino acid and a potent L-arginine antimetabolite. CAV can inhibit the proliferation of tumor cells in vitro and in vivo, but little is known regarding the molecular mechanisms mediating these effects. We demonstrated that the treatment of human lung adenocarcinoma A549 cells with CAV caused growth inhibition; G1 phase arrest is accompanied by accumulation of an incompletely phosphorylated form of the retinoblastoma protein, whose phosphorylation is necessary for cell cycle progression from G1 to S phase. In addition, CAV induces the expression of p53 and subsequent expression of a cyclin-dependent kinase inhibitor, p21/WAF1. The p53-dependent induction of p21/WAF1 and the following dephosphorylation of the retinoblastoma protein by CAV could account for the observed CAV-mediated G1 phase arrest.

Adenocarcinoma↗
PubMed1999

Plasma level of homocysteine is correlated to extracranial carotid-artery atherosclerosis in non-hypertensive Japanese.

BACKGROUND: Results of some epidemiologic studies in Western countries have clarified that hyperhomocysteinemia is a plausible risk factor for atherosclerotic vascular disease, but its role in Japanese communities is not known. DESIGN: A community-based cross-sectional design. METHODS: We performed a cross-sectional study of 474 elderly men aged 60-74 years in two Japanese rural communities (Noichi in southwestern Japan and Ikawa in northeastern Japan). We examined the association between plasma concentrations of homocysteine and the maximum intima-media thickness (assessed by ultrasonography). RESULTS: The prevalence of thickening was 10.7% for the lowest tertile of homocysteine level and 21.1% for the highest tertile. For the subjects without hypertension, the odds ratio for having carotid intima-media thickening was 5.8; it was significantly higher for the highest tertile of homocysteine level than it was for the lowest after adjusting for age, hypercholesterolemia, hypoalphalipoproteinemia, diabetes, and smoking by using a multiple logistic regression model. However, its correlation was not evident for those with hypertension. CONCLUSIONS: High levels of plasma homocysteine are correlated to extracranial carotid artery atherosclerosis in elderly men without hypertension in Japanese rural communities.

Aged↗
PubMed1999

Precise monitoring of porpoising behaviour of Adélie penguins determined using acceleration data loggers.

A new method using acceleration data loggers enabled us to measure the porpoising behaviour of Adélie penguins (Pygoscelis adeliae), defined as a continuous rapid swimming with rhythmic serial leaps. Previous hydrodynamic models suggested that leaping would be energetically cheaper when an animal swims continuously at depths of less than three maximum body diameters below the water surface. In the present study, free-ranging Adélie penguins leapt at a mean speed of 2.8 m s(-)(1) above the predicted threshold speed (0.18-1. 88 m s(-)(1)). Wild penguins reduced drag by swimming deeper (0.91 m) and did not swim continuously within the high-drag layer while submerged. This indicates that previous calculations may be incomplete. Moreover, leaps represented an average of only 3.8 % of the total distance travelled during the porpoising cycle, which would make energy savings marginal. Among the six penguins used in our study, two did not porpoise and three porpoised for less than 7 min, also indicating that this behaviour was not important during travel to and from foraging sites, as has been previously suggested. Birds mainly porpoised at the start and end of a trip. One explanation of porpoising might be an escape behaviour from predators.

Animals↗
PubMed1999

Elevated circulating levels of basic fibroblast growth factor and vascular endothelial growth factor in patients with acute myocardial infarction.

Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have both shown strong angiogenetic effects in ischemic animal models and it has been reported that these growth factors were increased after acute myocardial ischemia. However, there have been few reports on the serum levels of bFGF and VEGF after acute myocardial infarction (AMI), in particular there has not been a comparative study of bFGF and VEGF in human subjects. The time course of circulating levels of bFGF and VEGF was examined in 36 patients with AMI who were within 24h of the onset of the AMI. The serum bFGF and VEGF levels of 50 age- and sex-matched healthy volunteers served as the baseline value. All the patients had undergone coronary angiography on the day of admission (Day 0), but prior to that the serum bFGF and VEGF levels were examined by enzyme-linked immunoassay. The serum bFGF and VEGF levels were also evaluated on Days 7, 14 and 28. Creatine kinase, myosin light chain I and troponin-T were measured subsequently and radionuclide examinations were performed during the early phase of AMI to determine the infarct size. The serum bFGF levels were significantly increased at Day 0 and were maintained until Days 7 and 14. Although serum VEGF levels at Day 0 were similar to the baseline values, they showed a remarkable increase by Days 7 and 14. A high serum level of bFGF was detected in the acute phase of AMI, and a later increase in VEGF was determined in the sub-acute phase, which suggest that these 2 growth factors play an important role at different time points of the reconstructing process of infarcted myocardial tissue.

Acute Disease↗
PubMed1999

[Cohort study on risk factors for subarachnoid hemorrhage among Japanese men and women].

PURPOSE: To examine the risk factors for subarachnoid hemorrhage, for few prospective data have been available on risk factors of subarachnoid hemorrhage among Japanese. METHODS: A 9.4-year cohort study was conducted on 12,372 men and women, aged 40-69 years, free of history of stroke in six communities in Japan. RESULTS: During the follow-up, seventy-one incidents of subarachnoid hemorrhage occurred. After adjusting for age, serum total cholesterol, body mass index, history of diabetes mellitus, blood pressure category and drinking category, current smokers had a significantly increased risk of subarachnoid hemorrhage compared with 'never-smokers': multivariate relative risk (RR) [95% confidence interval (95% CI)] = 3.1(1.4-6.9) for women, 1.5(0.4-5.3) for men and 2.7(1.3-5.5)for men and women. Hypertensives had a significantly increased risk of subarachnoid hemorrhage compared with normotensives: multivariate RR(95% CI) = 3.1(1.6-6.0) for women, 4.3(1.5-12.0) for men and 3.4(2.0-5.9) for men and women. For men, heavy drinkers (> = 69 g per day ethanol), had a significantly increased risk of subarachnoid hemorrhage compared with 'never-drinkers': multivariate RR(95% CI) = 4.3(1.1-16.8). For women, the relationship between heavy drinking and risk was not examined due to the small number of heavy drinkers (n = 13). Multivariate RR(95% CI) for men who smoked currently and drank heavily compared with men who did not smoke currently nor drink heavily was 6.0(1.8-20.1). Multivariate RR(95% CI) for hypertensive men who drank heavily compared with normotensive or borderline hypertensive men who did not drink heavily was 13.0(3.9-43.9). Multivariate RR(95% CI) for hypertensive men and women who smoked currently compared with normotensive or borderline hypertensive men and women who did not smoke currently was 6.1(1.3-28.7) for men and 6.3(1.4-28.0) for women. Furthermore, the combination of smoking, hypertension and heavy drinking raised the risk of subarachnoid hemorrhage substantially: multivariate RR(95% CI) = 17.5(3.4-90.2). CONCLUSION: Smoking and hypertension appeared to increase the risk of subarachnoid hemorrhage. For men, although the association of smoking with the risk of subarachnoid hemorrhage was weak compared with women, the combination of smoking, hypertension and heavy drinking increased the risk substantially. For women, smoking appeared to be an independent risk of subarachnoid hemorrhage, and the combination of smoking and hypertension increased the risk in additive fashion.

Adult↗
PubMed1999

Delayed osteon formation in long-bone diaphysis of an 11-year-old giant cow with dermal dysplasia.

The transverse sections of radius diaphysis in an 11-year-old giant Holstein cow with dermal dysplasia of a collagen disorder-related skin fragility (Cow 1), probably based on increasing turnover of the dermal collagen as reported previously, were morphologically and physico-chemically investigated. Cow 1 had about one and a half times as much as the body weight of normal Holstein cows, aged 5 to 6.5 years with stabilized growth. The bone samples were compared with those of a 12-year-old Holstein cow as controls (Cow 2). It has been reported that the long-bone diaphysis of young calves and some herbivorous dinosaurs are occupied with laminar bone showing a concentric appositional formation, and that such a laminar bone is characteristically seen during the growing period of some farm animals and large dogs that show very rapid growth rates. Cow 1 had a smaller number of osteons than Cow 2 in the outer-half layer of the diaphysis, and showed an intermediate type between Cow 2 and a 1-year-old Holstein ox in the entire layers, although their bone volumes were similar among them. There were no significant differences in Ca and P concentrations and the Vickers microhardness values between the bone matrix of Cow 1 and Cow 2. The bone-collagen fibrils of Cow 1 showed uneven diameters and a disordered arrangement. Thus, there may be some relation in collagen formation between the bone matrix of Cow 1 and the dermis. From the remaining volume of laminar bone, Cow 1, aged 11 years, had probably shown growth until quite recently, so that we consider that Cow 1 became a giant animal, in the same way as some herbivorous dinosaurs.

Animals↗
PubMed1999

Experimental hypocalcemia induced by hemodialysis in goats.

To evaluate whether hemodialysis with a dialysate containing no calcium (Ca-free HD) can induce hypocalcemia and restore the clinical signs and blood biochemical changes in naturally occurred hypocalcemic disorder in ruminants, the clinical signs and the changes in plasma electrolytes and minerals concentrations were observed in goats during 6-hr hemodialysis. The four goats received hemodialysis with the dialysate containing calcium (Ca HD), and 10 days later they had Ca-free HD. The plasma ionized Ca (Ca++) and total Ca (TCa) concentrations were not affected by Ca HD, whereas the levels significantly decreased during whole period of Ca-free HD. The Ca++ and TCa concentrations were 0.69+/-0.06 mmol/l and 5.9+/-0.3 mg/dl at 6 hr of Ca-free HD, respectively. The clinical signs observed during Ca-free HD seemed to resemble to those in naturally occurred hypocalcemic cases that were reported previously. Therefore, Ca-free HD was suggested to be one of the possible methods to induce experimental hypocalcemia in ruminants.

Animals↗
PubMed1999

Immunohistochemical observations on the initial disorders of the epiphyseal growth plate in rats induced by high dose of vitamin A.

The initial disorders of the epiphyseal growth plate cartilage were immunohistochemically examined in the proximal tibia of rats administered a high dose of vitamin A. Male Wistar rats were given 100,000 IU/100 g body weight/day of vitamin A for administration periods of 1 to 5 days (Day 1 to 5) from 4 weeks after birth or were given deionized water and used as control. They were sacrificed after 5-bromo-2'-deoxyuridine (BrdU) injection on Day 1 to Day 5 to remove the tibiae. The tibiae were processed for immunohistochemical examinations using antibodies against type I, II, X collagens and BrdU. BrdU-incorporated chondrocytes and type X collagen-negative area were reduced since Day 2 and type X collagen-positive area was reduced since Day 4. The cartilage matrix partially lost type II collagen and deposited type I collagen in the epiphyseal growth plate near the periosteum on Day 5. These findings suggest that a high dose of vitamin A initially disturbed the differentiation from resting to proliferating chondrocytes, subsequently inhibited the differentiation from proliferating to hypertrophic chondrocytes, caused the chondrocytes to deviate from the process of normal differentiation, and finally resulted in the deformation of the epiphyseal growth plate.

Animals↗
PubMed1999

Relationship between occurrence of white diarrhea and changes of properties and components of blood and milk in their dams after parturition in Japanese Black calves.

We investigated the diet content and properties of blood and milk in 11 pairs of Japanese Black cows and their calves for the one month following delivery. Four pairs (group A) had been no cases of white diarrhea during the year prior to this study, and 7 pairs (group B) had been a high occurrence of white diarrhea in calves during the same period. Properties of dams' diet in groups A and B before the onset of white diarrhea in calves were as follows: TDN fullness rate 98 +/- 2% vs. 110 +/- 5%, DCP fullness rate 151 +/- 2% vs. 200 +/- 33%, and starch content 5 +/- 2% vs. 14 +/- 3%. Blood and milk samples were collected from cows weekly and at the onset of white diarrhea in calves. No calves in group A had white diarrhea, while 5 out of 7 calves in group B had the diarrhea in this study. All cows were fed mixed hay, but 3 out of 5 cows whose calves had white diarrhea had been additionally given 3.0-3.5 kg of corn-silage a day from 4-5 days before onset. In all cows in the white diarrhea development group, the fat content of milk increased by 2.94 +/- 1.82% at the day of onset in comparison before. Serum TG and BUN, respectively, increased by 3.8 +/- 1.3 mg/dl and 3.7 +/- 2.0 mg/dl. Feeding cows a low-starch diet and additional corn-silage may induce a transient increase in blood TG, BUN and milk fat, which may contribute to the occurrence of white diarrhea in calves.

Animal Feed↗
PubMed1999

Pancreatic phospholipase A2 induces bacterial translocation in rats.

The importance of pancreatic enzymes, particularly phospholipase A2 (PLA2), for bacterial translocation, which is considered to be one of the aggravating causes of acute pancreatitis, was investigated. Male rats were administered an intraperitoneal or intravenous injection of normal saline, PLA2, or amylase. Four days later, the mesenteric lymph nodes (MLNs) and portal blood of the animals were cultured. None of the animals had a positive portal blood culture. The MLNs contained enteric bacteria in 78% of the animals given 50 mg/kg of PLA2 intraperitoneally. 5 mg/kg of PLA2 intraperitoneally, 50 mg/kg of amylase intraperitoneally, or 50 mg/kg of PLA2 intravenously showed positive cultures in 25%, 20%, and 11%, respectively. None of the animals given intraperitoneal or intravenous normal saline had positive cultures of their MLNs. Intraperitoneal injection of 25 mg/kg of nafamostat mesilate just before intraperitoneal PLA2 (50 mg/kg) resulted in a reduction of positive MLNs from 70% to 30%. The cecal myeroperoxidase (MPO) activity of animals administered 50 mg/kg of PLA2 intraperitoneally was significantly higher compared with animals administered saline intraperitoneally. These results indicate that intraperitoneal leakage of PLA2 plays an important role in bacterial translocation during acute pancreatitis and that administration of a protease inhibitor may be effective against the bacterial translocation.

Acute Disease↗
PubMed1999

[Three-dimensional reconstruction of functional brain images].

We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: 1) routine images by SPM, 2) three-dimensional static images, and 3) three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface model is the most common method of three-dimensional display. However, the volume rendering method may be more effective for imaging regions such as the brain.

Brain↗
PubMed1999

N-acetyl-beta-D-glucosaminidase activity in urine of cows with renal parenchymal lesions.

OBJECTIVE: To measure N-acetyl-beta-D-glucosaminidase (NAG) activity in urine of cows with renal diseases and to correlate values for NAG activity with renal lesions. ANIMALS: 8 lactating Holstein cows and a Japanese Shorthorn cow, all of which had renal disease. PROCEDURE: Urine samples were collected, and urinary NAG activity and creatinine concentration were measured. The NAG activity was expressed as units per gram of creatinine (NAG index). Cows were euthanatized, necropsy was performed, and correlations between results for urinary NAG index and histopathologic findings for the kidneys were evaluated. RESULTS: The NAG activity and NAG index in urine samples obtained from cows with interstitial nephritis were high, ranging from 4.2 to 13.6 U/L and 3.5 to 23.0 U/g, respectively. A cow with renal amyloidosis also had high values for urinary NAG activity and NAG index. Histologic examination of the kidneys revealed various kinds of parenchymal lesions. However, urinary NAG index in cows with enzootic bovine leukosis was low. CONCLUSIONS AND CLINICAL RELEVANCE: Cows with renal diseases had high urinary NAG indexes that correlated well with their renal lesions, except for cows with enzootic bovine leukosis. Therefore, measurement of NAG index in urine samples has the potential to provide new perspectives on clinical diagnosis of renal disease in cattle.

Acetylglucosaminidase↗
PubMed1999

[A case report of successful mitral valve replacement for congenital mitral stenosis associated with coarctation of the aorta and ventricular septal defect].

A 5-month-old infant with coarctation of the aorta, ventricular septal defect and mitral stenosis known as "Shone's anomaly" is presented. He underwent the repair of coarctation of the aorta by means of the extended aortic arch anastomosis and banding of the pulmonary trunk at 1 month of age and the patch closure of ventricular septal defect and debanding of the pulmonary trunk at 3 months of age in our institution. About 2 months after second surgery, he had been admitted to our institution due to developing tachypnea and he needed the support of mechanical ventilation. The chest X-ray showed pulmonary congestion and the echocardiography revealed only one papillary muscle of mitral valve and pressure gradient about 30 mmHg through mitral valve. Mitral stenosis due to parachute mitral valve was suspected and he was subjected to an emergent surgery. Initially we performed mitral valve repair for parachute mitral valve but echocardiography during the surgery revealed moderate grade of mitral regurgitation and a hemodynamics was not satisfactory. Eventually mitral valve replacement was successfully done with Carbo-Medics mechanical valve (19 mm in diameter) in the position of left atrial wall because his mitral annulus was so small as 10 mm in diameter. The postoperative course was uneventful and the patient has been doing well.

Aortic Coarctation↗
PubMed1999

[Docetaxel therapy against anthracycline resistant breast cancer].

To evaluate the efficacy of docetaxel therapy against anthracycline-resistant breast cancer, twenty patients were treated with docetaxel. Of the 20 patients pretreated with anthracycline, 17 were clinically anthracycline-resistant and the remaining three were refractory to anthracycline on histoculture drug response assay. Nine patients had loco-regional recurrence and 11 had distant +/- loco-regional recurrence. Docetaxel (49-60 mg/m2) was administered every 4 weeks, and was infused 1-13 times (median; 3 times). Of the 19 evaluable patients, eight (42%) showed partial response with the docetaxel therapy. Durations of the response ranged from 1 to 8 months (median; 4 months). Major adverse effects of the therapy were alopecia, neutropenia, and leucocytopenia. Hypersensitivity reaction was observed in one case. In addition, severe adverse effects such as grade 2 pneumonia and grade 4 diarrhea were found in one patient each. In conclusion, although the adverse effects are not negligible, docetaxel therapy is effective against anthracycline-resistant breast cancer.

Aged↗
PubMed1999

[Factors relate to participation in medical checkups in a rural community an analysis including social network scores].

Since 1969, community-based stroke prevention programs have been conducted in N town, Kochi prefecture. To clarify factors related to participation in medical checkups including social networks, a cross-sectional questionnaire survey was performed on 6,704 residents aged 40 and over in N town in 1996. 1. Location of the workplace, types of medical insurance and interest in health were significantly associated with participation in medical checkups. 2. Participation in medical examinations provided at the workplace was significantly, inversely related with participation rates in community checkups in the group aged 40 to 59 years. 3. Low independence level in daily activities was inversely associated with participation rates for medical checkups in groups aged 60 years and older. 4. Visiting medical facilities was inversely associated with the participation rate for medical checkups in female groups. 5. The group with the highest social networks score (5 points) had the highest participation rate for medical checkups. After adjusting for other participation related factors, social networks scores had a significantly positive association with the participation rate for medical checkups provided by the Health Services for the Elderly Act.

Adult↗