Biomedical subjects

Y Arai

Publications and source records attributed to Y Arai.

At least 109 records · Page 6Linked to original sources

PubMed2001

Serum insulin-like growth factor-1 in centenarians: implications of IGF-1 as a rapid turnover protein.

BACKGROUND: It is well documented that serum insulin-like growth factor 1 (IGF-1) levels as well as growth hormone secretion decline with advancing age. Low levels of IGF-1 are shown to be associated with low activity of growth hormone, low lean mass, and high body fat mass; however, in the elderly, the relationship has not been confirmed. METHODS: We studied serum IGF-1 levels in 49 centenarians, who are at the ultimate stage of physiological senescence, and investigated the possible relationship between IGF-1 and body mass index, lipid parameters, nutritional indices, physical and cognitive function, and frequency of hip fracture. As nutritional indices, serum levels of albumin, prealbumin, transferrin, and retinol binding protein were measured. Cognitive function of the centenarians was assessed by clinical dementia rating. RESULTS: In the centenarians, the mean levels of IGF-1 were relatively low, indicating that there is an age-associated decline in IGF-1 even in the extremely old age. We demonstrated a strong association of IGF-1 with prealbumin and retinol binding protein (r2 = .192, .195, respectively); however, there was no association with albumin, transferrin, or body mass index. Interestingly, centenarians with lower IGF-1 levels had a higher prevalence of definitive dementia. CONCLUSIONS: These data suggest that serum IGF-1 levels in the centenarians appeared to reflect their short-term nutritional status as a rapid turnover protein. It is also suggested that low levels of serum IGF-1 may be involved in the progression of dementia in the oldest old.

Aged↗

PubMed2001

A study of pretreatment nomograms to predict pathological stage and biochemical recurrence after radical prostatectomy for clinically resectable prostate cancer in Japanese men.

BACKGROUND: Accurate pretreatment identification of the risks that prostate cancer has extended beyond the gland and that it will recur would significantly influence practice patterns. Preoperative nomograms to predict such risks have not been developed for the oriental male population. METHODS: Construction of nomograms to predict preoperatively pathological outcome and early biochemical failure following radical prostatectomy in Japanese males was based on logistic regression analysis, with predicted probabilities and 95% confidence intervals for the final model being obtained by repeating the analysis on 1000 bootstrap samples from the original cohort. RESULTS: Prostate-specific antigen level, clinical stage and biopsy Gleason score contributed significantly to the prediction of pathological stage and of biochemical failure in the univariate analysis (p < 0.001). Combined use of these three variables predicted these treatment outcomes better than any single variable (p < 0.001). Nomograms combining these three variables to predict final pathological findings and early biochemical failure were then developed. The medians and 95% confidence intervals of the predicted probabilities are presented in the nomograms. CONCLUSIONS: This information enables clinicians to use their nomograms when counseling Japanese patients, leading to more informed treatment decisions and helping to identify those with a high risk of early biochemical failure. The nomograms may also be used to assure comparability of different treatment modalities in investigational trials.

Aged↗

PubMed2001

Validity and reproducibility of a self-administered food-frequency questionnaire to assess isoflavone intake in a japanese population in comparison with dietary records and blood and urine isoflavones.

Valid food-frequency questionnaires (FFQ) need to be developed to assess isoflavone intake in investigations of its possible association with the lower incidence of breast and prostate cancer in Asian countries. We investigated the validity and reproducibility of isoflavone (daidzein and genistein) intakes from self-administered semiquantitative FFQ used in the JPHC Study (Japan Public Health Center-based Prospective Study on Cancer and Cardiovascular Diseases). We also investigated the number of food items that would be sufficient to ensure validity and reproducibility. We collected FFQ, dietary records (DR), blood and urine samples from 215 subjects among JPHC Study participants, estimated isoflavone intakes from FFQ and DR, and measured serum isoflavone concentration and urine isoflavone excretion. For daidzein, mean intakes estimated from FFQ and DR, serum concentration and urine excretion were 18.3 mg/d, 14.5 mg/d, 119.9 nmol/L and 17.0 micromol/d and for genistein, 31.4 mg/d, 23.4 mg/d, 475.3 nmol/L and 14.2 micromol/d, respectively. Results were similar when analyzed by sex. Spearman correlation coefficients for daidzein of energy-adjusted intakes from FFQ with those from DR, serum concentration and creatinine-adjusted urinary excretion were 0.64, 0.31 and 0.43, respectively. Correlations between two FFQ estimates with a 1-y interval were 0.76. Results were similar for genistein. The shorter version of the FFQ with three items (natto, miso and tofu for miso soup) showed a similar correlation. The original FFQ and the shorter versions have sufficient validity and reproducibility to be used in epidemiologic studies.

Diet Records↗

PubMed2001

Laparoscopic partial nephrectomy with a microwave tissue coagulator for small renal tumor.

PURPOSE: Laparoscopic partial nephrectomy is a challenging procedure due to the risk of excessive bleeding. We evaluated the usefulness of a microwave tissue coagulator during laparoscopic partial nephrectomy for small renal tumor. MATERIALS AND METHODS: From January to July 2000, 6 patients with small renal tumors, from 11 to 25 mm. in diameter, underwent laparoscopic partial nephrectomy with a microwave tissue coagulator without renal pedicle clamping. There were 4 patients who underwent the transperitoneal and 2 who underwent the retroperitoneal approaches. RESULTS: Mean operating time was 186 minutes (range 131 to 239), and blood loss was minimal. Complications were mild and tolerable, and there was no significant deterioration of renal function. CONCLUSIONS: Laparoscopic partial nephrectomy with a microwave tissue coagulator is a useful and less invasive method for treatment of select small renal tumors. Long-term followup of patients is warranted to determine the potential for cancer control with this method.

Adult↗

PubMed2001

Germline mutation of dihydropyrimidine dehydrogenese gene among a Japanese population in relation to toxicity to 5-Fluorouracil.

5-Fluorouracil (5FU) is most commonly used in chemotherapy for human malignancy. Over 80% of administered 5FU is metabolically degraded by dihydropyrimidine dehydrogenase (DPD), a primary and rate-limiting enzyme in the 5FU metabolic pathway. A DPD-deficient phenotype among cancer patients, which has posed a serious problem in 5FU-based chemotherapy, was reported to be in part ascribed to germline mutations in dihydropyrimidine dehydrogenase (DPYD) gene. Therefore, we for the first time examined the frequencies and types of germline mutations in the DPYD gene among a total of 107 Japanese cancer patients and healthy volunteers. Of 214 alleles examined among them, 181 alleles were of the same type, which was assigned as wild type; 21 alleles revealed a nucleotide substitution resulting in silent mutation; and the remaining 12 alleles showed five types of nucleotide deletion or substitutions resulting in one frameshift and four missense mutations. Three of them, A74G, 812delT and L572V, were novel mutations. None of the study subjects showed homozygous frameshift or missense mutated alleles. We also studied the association between toxic response to 5FU and heterozygous frame shift or missense mutation of the DPYD gene among eight cancer patients who had received 5FU-based chemotherapy. These patients did not show any adverse effects higher than grade 3, suggesting that heterozygotes are not associated with increased toxicity to 5FU. Our results indicate that a very small percentage, about 0.2%, of the Japanese population seems to carry homozygous mutations in DPYD gene, mutations which possibly indicate genetically increased toxicity of 5FU-based chemotherapy.

Antimetabolites, Antineoplastic↗

PubMed2001

Changes in the vestibulo-ocular reflex after plugging of the semicircular canals.

The gain of the angular vestibulo-ocular reflex (aVOR) was determined in monkeys by rotation about a spatial vertical axis while upright or statically tilted forward and backward. Horizontal, vertical, and roll gains were determined at each head orientation and plotted as a function of head tilt. Before canal plugging, animals had maximal (spatial) horizontal gains when upright (spatial phase 0 degrees) and maximal roll gains when tilted forward or backward 90 degrees. Plugging caused striking changes in the characteristics of the aVOR gains at low frequencies. After plugging of the vertical canals, maximal horizontal and roll gains both occurred at head tilts of approximately 30 degrees forward. When the lateral canals were plugged, maximal horizontal and roll responses occurred when the head was tilted back approximately 50 degrees. The aVOR gains of the canal-plugged animals were also affected by stimulus frequency. In every instance, as stimulus frequency increased, the spatial phases shifted toward the normal response, that is, the response before plugging. This normalization effect was observed even in the animals with all six semicircular canals plugged, indicating that normalization was not due to spatial adaptation. A three-dimensional dynamic and kinematic model of the aVOR was able to account for all types of canal plugging by a simple change in the dominant time constant of the plugged canals from 3 s to 5 s to approximately 0.07 s. The model accurately predicted responses of the normal and canal-plugged animals at all frequencies. These data show that the central vestibular system does not spatially adapt to losses resulting from canal plugging.

Animals↗

PubMed2001

Improvement in right lung atelectasis (middle lobe syndrome) following administration of low-dose roxithromycin.

Middle lobe syndrome is a distinct clinical entity characterized by right middle lobe atelectasis. Prompt diagnosis and initiation of medical therapy including the administration of antibiotics and the avoidance of irritating agents may be effective. However, abnormal shadows on chest radiography remain unchanged even when acute symptoms have disappeared, suggesting latent lesional inflammation or recurrence. We describe 2 cases of atelectasis in the middle lobe of the right lung which resolved completely after administration of low-dose roxithromycin. Thus, low-dose therapy with a macrolide could be of interest or some value in these cases, but it is too early to draw a definite conclusion.

Aged↗

PubMed2001

Central serotonergic mechanisms on head twitch response induced by benzodiazepine receptor agonists.

Intraperitoneal injection of benzodiazepine receptor agonists (estazolam, zopiclone, triazolam: 0.03-0.24 mmol/kg) induces the head twitch response (HTR). The present study was undertaken to examine the possible participation of the serotonergic system in the mechanism of head twitches induced by benzodiazepine receptor agonists (BZ-RAs). The HTR induced by BZ-RAs was suppressed by pretreatment with ketanserine (1 mg/kg, i.p.), a selective 5-HT(2) receptor antagonist. Pretreatment with fluoxetine (10 mg/kg, i.p.), a 5-HT reuptake inhibitor, and 8-hydroxy-2-(di-n-propylamino)tetralin, a 5-HT(1A) receptor agonist, also suppressed the HTR induced by BZ-RAs. These results suggest that the HTR induced by BZ-RAs may be the result of an activation of postsynaptic 5-HT(2) receptors, probably due to direct action.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed2001

1,6-Asymmetric induction during the conjugate addition of arylcopper reagents to a chiral sulfinyl-substituted pyrrolyl alpha,beta-unsaturated amide.

The asymmetric conjugate addition of arylcopper reagents derived from aryl Grignard reagents and copper(I) iodide to a chiral 1-[2-(p-tolylsulfinyl)]pyrrolyl cinnamide proceeded smoothly to give (3R)-adducts with high diastereoselectivities (> or =92% de) in high yields. Conjugate additions either of the cinnamide with the alkyl Grignard reagent-copper(l) iodide combination or of the crotonamide derivative with aryl Grignard reagent-copper(l) iodide gave moderate to good diastereoselectivities. With these sulfinyl pyrrolyl alpha,beta-unsaturated amides, the chiral auxiliary was efficiently recovered without any loss of optical purity after asymmetric conjugate addition.

Chromatography, High Pressure Liquid↗

PubMed2001

Role of nitric oxide in regulation of coronary blood flow in response to increased metabolic demand in dogs with pacing-induced heart failure.

The role of endothelium-derived nitric oxide (NO) in the metabolic control of coronary blood flow (CBF) in heart failure (HF) is poorly understood, so the present study investigated the effects of inhibitors of NO synthesis on the response of CBF to changes in myocardial oxygen consumption (MVO2) in dogs with HF produced by rapid ventricular pacing and in control dogs. The CBF, MVO2, and other hemodynamic parameters were measured in anesthetized animals. Before infusion of Nomega-nitro-L-arginine methyl ester (L-NAME), the increases in CBF and MVO2 during pacing tachycardia were not significantly different between the control and HF dogs. Intracoronary infusion of L-NAME did not alter the responses of CBF or MVO2 to pacing tachycardia in the control dogs, but in the HF dogs, it reduced the CBF response to pacing tachycardia without altering the tachycardia-induced changes in MVO2. Intracoronary infusion of L-arginine reversed the effect of L-NAME. These results suggest that in HF dogs NO contributes to the regulation of CBF in response to an increased metabolic demand.

Animals↗

PubMed2001

[Atorvastatin (Lipitor): a review of its pharmacological and clinical profile].

Hypercholesterolemia is a major risk factor for the development of coronary heart disease. HMG-CoA reductase inhibitors have been used as first-line drugs because of both their superior cholesterol lowering effect and reliable safety profile. Since there are many patients whose plasma cholesterol level does not reach the therapeutic target even if reductase inhibitors are available, more effective drugs have been strongly required for a long time. Atorvastatin, one of the most recently introduced statins, produces greater plasma LDL-cholesterol reductions than other statins. This pronounced effect of atorvastatin seems to be due to its long-lasting action, presumably a reflection of longer residence time of atorvastatin and its active metabolites in the liver. Clinical trials of atorvastatin have also demonstrated marked plasma triglyceride reductions. The triglyceride reduction with atorvastatin seems to stem from the following two indirect mechanisms, limiting VLDL secretion from the liver and increase in clearance of triglyceride-rich lipoprotein via induced LDL receptors from plasma. Eleven clinical trials of atorvastatin, which have been developed in Japan, clearly demonstrated its ability to reduce LDL-C levels more strongly and in significantly more patients to LDL-C treatment goals than other reductase inhibitors with similar safety profiles. Therefore, atorvastatin adds a new dimension to the effective management of hypercholesterolemia and combined hyperlipidemia.

Animals↗

PubMed2001

Case report: Hepatic arterial occlusion following infusion catheter placement: recanalization using the Palmaz stent.

We report two cases in which hepatic arterial occlusion developed soon after percutaneous catheter placement for hepatic arterial infusion chemotherapy in malignant hepatic neoplasms. A replaced hepatic artery and a proper hepatic artery, respectively, became occluded in these cases. In both, because the tip of a side-holed catheter for arterial infusion was fixed in place, we performed recanalization without removing the indwelling catheter. Despite the presence of the catheter, a stent could be inserted into the occluded portion of the hepatic artery. Recanalization of the hepatic artery was achieved with stent placement, and continuation of hepatic arterial infusion became possible.

Arterial Occlusive Diseases↗

PubMed2001

Introduction of bacterial metabolism into higher plants by polycistronic transgene expression.

Multiple-gene transformation is required to improve or change plant metabolisms effectively; but this many-step procedure is time-consuming and costing. We succeeded in the metabolic engineering of tobacco plants by introducing multiple genes as a bacteria-type operon into a plastid genome. The tobacco plastid was transformed with a polycistron consisting of three bacterial genes for the biosynthesis of a biodegradable polyester, polyhydroxybutyrate (PHB). Accumulation of PHB in the leaves of the transgenic tobacco indicated that the introduced genes were polycistronically expressed. This "phyto-fermentation" system can be used in plant production of various chemical commodities and pharmaceuticals.

Acetyl-CoA C-Acyltransferase↗

PubMed2001

Clinical application of a new compact computed tomography system for evaluating the outcome of regenerative therapy: a case report.

BACKGROUND: The limitations of conventional 2-dimensional (2-D) radiographs have been emphasized in many studies. Because the image is a 2-D map of the 3-dimensional (3-D) tooth and periodontal tissue, these structures may be superimposed on each other. Recently, 3-D image analysis by computed tomography (CT) was introduced to dentistry, but it has been used only rarely in the periodontal field. METHODS: The purpose of this case report was to introduce the clinical application of a newly developed, compact computed tomography system for evaluating the outcome of regenerative therapy in an adult patient with periodontitis (male, aged 55 years). To evaluate the bone defects including furcation involvement, we took an intraoral radiograph and performed CT scanning on tooth #19. We recorded a number of clinical parameters at the time of surgery. We compared the images of the bone defect obtained by CT images and the conventional radiograph with the true bone defect morphology at the surgical site. RESULTS: One year after the periodontal surgery, we again took CT scans and a conventional radiograph, and the new images of the bone defect were compared and evaluated. The new CT images were reconstructed for 3-D evaluation and compared with those taken before surgery. The CT provides 3-D images of excellent quality for evaluating the morphology of the periodontal bone defect and furcation involvement. CONCLUSIONS: We consider that CT is a useful aid in periodontal examination and diagnosis, and in the prediction and evaluation of periodontal treatment outcomes.

Alveolar Bone Loss↗

PubMed2001

Electrode reaction of Pu3+/Pu couple in LiCl-KCl eutectic melts: comparison of the electrode reaction at the surface of liquid Bi with that at a solid Mo electrode.

The electrode reaction of Pu3+/Pu couple at the interface between LiCl-KCl eutectic melt containing PuCl3 and liquid Bi phase was investigated by cyclic voltammetry at 723, 773 and 823 K. For comparison, the system was also studied using a solid Mo electrode in place of the liquid Bi electrode. It was found that the electrode reaction of Pu3+/Pu couple at the Bi electrode was almost reversible. The redox potentials of Pu3+/Pu couple at the liquid Bi electrode in the LiCl-KCl eutectic melt containing 0.87 wt% PuCl3 (0.0014 mole fraction) at 723, 773 and 823 K were observed to be more positive by 0.575, 0.572 and 0.566 V, respectively, than those at the Mo electrode. These differences in potential were thermodynamically analyzed by assuming a lowering of the activity of Pu in Bi phase according to the alloy formation of PuBi2.

Journal Article↗

PubMed2001

A new light on caloric test--what was disclosed by three dimensional analysis of caloric nystagmus?

For better understanding of caloric nystagmus, this phenomenon will be reviewed historically in three stages. 1) The first light on caloric nystagmus was thrown by Barany 1906. Through direct observation of eye movements, Barany established the caloric test as an important tool to determine the side of lesion for vertigo. 2) The second light is shed by electrooculogram (EOG) from the late 1950th. EOG enabled qualitative analysis of caloric nystagmus, and proved Barany's convection theory, but resulted in neglect of vertical and roll eye movements. 3) The third light is gained by 3D recording of eye movements started from the late 1980th. 3D recordings of eye movements enabled us to analyze the spatial orientation of caloric nystagmus, and disclose the close correlation of the nystagmus components in the head vertical and the space vertical planes, suggesting a contribution of the velocity storage integrator. The 3D property of caloric nystagmus will be explained in detail.

Animals↗

PubMed2001

[Suggestions from a centenarian study--aging and inflammation].

With the numbers of elderly increasing rapidly, it is important for both individuals and society that the oldest old maintains autonomy. To know how to attain successful aging, we investigate the status of centenarians. The characteristics of centenarians in Tokyo is 1) low level of nutritional parameters, 2) low level of cholesterol and HDL-cholesterol, 3) low level of red blood cells and hemoglobin, 4) high level of CRP, 5) high level of homocysteine, 6) high level of von Willbrand factor. The incidence of dementia is 59.3%. Are these characteristics due to aging itself or other factors? We examined the effect of nutritional status, inflammation and level of homocysteine on the characteristics. The level of albumin is associated with serum level of lipid, RBC, ADL and cognitive function. The level of CRP is related to the level of albumin, suggesting that inflammation is related to nutritional status. The level of homocysteine is associated with the level of von Willbrand factor, suggesting that homocysteine is related to endothelial injury. From these data, we propose the hypothesis that proinflammatory status is associated with aging, resulting in a part of characteristics of centenarians. Homocysteine is partly responsible for endothelial injury. Intervention to suppress proinflammatory status and homocysteine level may promote QOL in the oldest old.

Aged↗

PubMed2001

[Effects of acupuncture therapy on low back pain and/or knee pain in elderly patients].

In April 1999, 75 elderly patients (mean age: 79 years old) with low back pain and/or knee pain visited an acupuncture and physical therapy unit in a geriatric hospital. A cross-sectional study was carried out in order to evaluate the effects of acupuncture therapy on low back pain and/or knee pain in elderly patients. Among them, 60 patients answered that their pain diminished following their therapy. The proportion of patients who were treated with acupuncture therapy were higher in these 60 patients than the other 15 patients (55.5% vs. 26.7%, p = 0.05). The result suggests that acupuncture therapy may be able to relieve low back pain and/or knee pain in elderly patients. However, 46% of the patients with acupuncture therapy were also treated with other types of physical therapy. Further studies should be recommended to confirm the effects of acupuncture therapy on low back pain and/or knee pain.

Acupuncture Therapy↗