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Biomedical subjects

Y Arai

Publications and source records attributed to Y Arai.

At least 289 records · Page 16Linked to original sources
PubMed1998

[Separate operation for extensive aneurysm (mega-aorta) complicated with ischemic heart disease].

A seventy one year-old woman, who had an arch and thoracoabdominal aortic aneurysm (type II according to Crawford classification) with ischemic heart disease, underwent a separate operation using the elephant trunk method. At first, she underwent the ascending aorta and arch replacement the with elephant trunk technique, and, underwent CABG simulutaneously utilizing the separate extra corporeal circulation and hypothermic circulatory arrest. The Chest and abdominal CT revealed the enlargement of abdominal aortic aneurysm 5 months after operation. The second operation was performed using Stoney's spiral opening method and the revasculization of spinal arteries (Th6, 7 and Th9) underwent the segmental aortic clamping to prevent spinal cord ischemia. Furthermore, the second operation was performed using selective perfusion to visceral arteries and F-F bypass for the prevention of visceral ischemia. Each flow rate by selective perfusion in major abdominal blanches was from 50 to 100 ml/min. Therefore, hepatorenal dysfunction and paraparesis did not occur after the second operation. It was suggested that the segmental aortic clamping and the selective perfusion to visceral arteries with F-F bypass may be effective to prevent the ischemia of the spinal cord and abdominal organs.

Aged↗
PubMed1998

Production of urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor-1 (PAI-1) in human brain tumours.

We investigated the role of plasminogen activators (PAs) and their inhibitor (plasminogen activator inhibitor-1, PAI-1) in human brain tumours. The amounts of urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1), and the activity of u-PA and t-PA were determined by enzyme-linked immunosorbent assay (ELISA), and u-PA and PAI-1 were immunolocalized using monoclonal antibodies in human brain tumours and normal brain tissues. The tissues were surgically removed from 64 patients; normal brain tissue (5 cases), low-grade glioma (4 cases), high-grade glioma (17 cases), metastatic tumour (9 cases), meningioma (benign 12 cases, malignant 6 cases), acoustic schwannoma (11 cases). u-PA activity and u-PA and PAI-1 antigen levels were significantly elevated in malignant brain tumours (malignant meningiomas, high-grade gliomas, and metastatic tumours) and acoustic schwannomas but very low in benign meningiomas, low-grade gliomas and normal brain. There was no difference in t-PA antigen levels among normal and malignant tissues, however levels of t-PA activity were markedly decreased in metastastic tumours. All malignant brain tumour tissues showed positive immunostaining for u-PA and PAI-1, however, some tumour cells showed negative intensity while others showed strong intensity for these antibodies. This contrasts to the homogeneous staining pattern found in acoustic schwannoma. These findings indicate that malignancy in human brain tumours is associated with elevated levels of u-PA and PAI-1 and that an imbalance between these proteins in a micro-environment contributes (ascribes) to tumour cell invasion.

Adolescent↗
PubMed1998

Interstitial laser coagulation for management of benign prostatic hyperplasia: a Japanese experience.

PURPOSE: The principle of interstitial laser coagulation is to shrink the prostate by generating intraprostatic necrosis without damaging the urethra or causing tissue sloughing. The clinical efficacy and durability of interstitial laser coagulation in the treatment of benign prostatic hyperplasia (BPH) were evaluated. MATERIALS AND METHODS: From December 1993 to June 1996, 76 patients with symptomatic BPH were treated with interstitial laser coagulation. A neodymium:YAG laser was used in combination with a specially designed interstitial thermotherapy light guide. The tip of the light guide was inserted into each lobe of the prostate transurethrally under direct vision. All evaluations were made at baseline and then 1, 3, 6 and 12 months after therapy. Treatment outcome was evaluated by International Prostate Symptom Score (I-PSS), flow rate and post-void residual urine volume. Disease specific quality of life was assessed via a quality of life assessment score and a BPH impact index. Independent of symptom assessment, a self-reporting questionnaire was prepared at 3 months postoperatively regarding satisfaction with treatment and sexual function. RESULTS: Among 44 patients followed to 12 months the mean I-PSS significantly decreased from 20.4 at baseline to 7.4, representing 64% improvement (p <0.001). Peak flow rate increased by 50% from a preoperative average of 7.4 to 11.1 ml. per second at 12 months in 42 patients (p <0.001). The post-void residual volume decreased by 57% from 102 to 44 ml. at 12 months in 40 cases (p <0.001). Steady and progressive improvement was observed on quality of life assessment and BPH impact index scores at 3, 6 and 12 months. No patients reported new onset of erectile dysfunction. No serious side effects were observed, except for loss of ejaculation in 3 cases and seminal vesicle abscess in 1. Only 6 patients (8%) required re-treatment for persisting obstructive symptoms during 12 months of followup. A recent change in methods towards more aggressive treatment plausibly influenced the outcomes to require less repeat treatment. CONCLUSIONS: After the interstitial laser coagulation procedure satisfactory results were obtained and improvement lasted through 12 months. Although the optimal number of fiber placements for each prostate is not known, more aggressive treatment appears to provide better outcomes.

Aged↗
PubMed1998

Effect of YM435, a novel dopamine DA1 receptor agonist, in a canine model of acute congestive heart failure.

1. The effects of YM435, a dopamine DA1 receptor agonist, were evaluated in a canine model of acute congestive heart failure. 2. The model was induced in open-chest anesthetized dogs by left anterior descending coronary artery ligation, volume loading, and intravenous infusion of angiotensin II. This resulted in a moderate and stable congestive heart failure characterized by reduction in cardiac output and increases in left ventricular end-diastolic pressure and total peripheral vascular resistance. 3. Intravenous infusion of YM435 (1 microgram/kg/min) significantly decreased left ventricular end-diastolic pressure, total peripheral vascular resistance and mean blood pressure and significantly increased cardiac output and renal blood flow in this model. 4. These results indicate that intravenous infusion of YM435 can improve hemodynamics and cardiac function in a canine model of acute congestive heart failure. YM435 may be a useful therapeutic agent for the treatment of congestive heart failure.

Animals↗
PubMed1998

Effect of YM435, a dopamine DA1 receptor agonist, in a canine model of ischemic acute renal failure.

1. The effects of (-)-(S)-4-(3,4-dihydroxyphenyl)- 1,2,3,4-tetrahydroisoquinoline-7,8-diol monohydrochloride monohydrate (YM435), a dopamine DA1 receptor agonist, were evaluated in a canine model of ischemic acute renal failure (ARF). 2. ARF was induced by clamping the left renal artery for 1 hr and subsequent reperfusion of the left kidney in anesthetized uninephrectomized dogs. 3. After 1-hr complete renal artery occlusion, an intravenous infusion of either YM435 (0.3 microg/kg/ min) or 0.9% saline (vehicle) was begun and continued for 1 hr. 4. In the vehicle group, renal ischemia markedly decreased glomerular filtration rate, urine flow and urinary sodium excretion. The YM435 group was characterized by significant recoveries in glomerular filtration rate, urine flow, and urinary sodium excretion as compared with the vehicle group. 5. These results indicate that YM435 can facilitate recovery in glomerular filtration rate, urine flow, and urinary sodium excretion in a canine model of ARF induced by ischemia. YM435 may be useful in the preservation of renal function in ischemia-induced ARF.

Acute Disease↗
PubMed1998

Startle-induced epilepsy in a patient with epidermal nevus syndrome.

Startle-induced epilepsy was observed in a 5-year-old boy with epidermal nevus syndrome. He manifested linear nevus on the face and neck, mild mental retardation, and right hemiparesis. Massive myoclonus, followed by tonic seizures, had been triggered by unexpected auditory stimuli since 3 years of age. The startle-induced seizures were the only epileptic manifestation. Interictal EEG occasionally depicted spontaneous focal spikes and waves in the left frontotemporal area, and ictal EEG depicted vertex spikes and then diffuse slow spike-and-wave complex bursts. Left frontal and perisylvian cortical atrophy and a white matter abnormality in the left frontal area were revealed by magnetic resonance imaging. Single photon emission computed tomography demonstrated diffuse low perfusion in the left cerebral hemisphere. Lower amplitude potentials in the left cerebral cortex were evident during somatosensory evoked potential evaluation. These results indicate that hemispheric dysfunction could cause startle-induced epilepsy in this patient.

Acoustic Stimulation↗
PubMed1998

Vascular endothelial growth factor in brains with periventricular leukomalacia.

Vascular development was studied by means of immunohistochemistry, using a vascular endothelial growth factor (VEGF) antibody in human normal and periventricular leukomalacia brains. In the cerebral cortex, VEGF was expressed transiently in the endothelial cells of vessels in the leptomeninges, cortex, deep white matter, subependymal germinal layer, ependymal cells facing the lateral ventricles, and choroid plexus epithelia. In the leptomeninges, VEGF was expressed from 20 to 40 weeks gestation. In the cerebral cortex and deep white matter, VEGF was expressed from 17 weeks gestation, increased with maturation, was highest between 24 and 28 weeks gestation, and decreased gradually thereafter. In the subependymal germinal layer, VEGF was expressed the earliest at 9 weeks gestation, increased with maturation, was highest between 20 and 24 weeks gestation, and then decreased. In the ependymal cells and choroid plexus epithelia, VEGF was expressed between 22 and 40 weeks gestation and between 9 and 37 weeks gestation, respectively. VEGF may be transiently expressed in the vessels in the fetal and neonate periods in connection with vascular maturation and proliferation. In periventricular leukomalacia brains, VEGF was expressed in both astrocytes and endothelial cells in vessels that comprised neovascularization around foci of necrosis. VEGF plays important roles in embryonic angiogenesis and neovascularization around foci of necrosis.

Astrocytes↗
PubMed1998

Dual action of CD30 antigen: anti-CD30 antibody induced apoptosis and interleukin-8 secretion in Ki-1 lymphoma cells.

CD30 is a member of the tumor necrosis factor superfamily. In this study, we examined the effect of four anti-CD30 (aCD30) antibodies (Abs) on CD30-positive anaplastic large cell lymphoma-derived cell line, Ki-JK. The aCD30 Abs suppressed [3H]thymidine (TdR) incorporation. With a TdT mediated dUTP-biotin nick end labeling method, apoptosis was detected in Ki-JK cells at day 5 after the addition of aCD30 Ab to the culture. Genistein, an inhibitor of protein tyrosine kinase, had no effect on aCD30 Ab-induced apoptosis. The aCD30 Ab simultaneously induced interleukin-8 (IL-8) secretion in the Ki-JK cells. In culture of the Ki-JK cells with aCD30 Ab for 5 days, the IL-8 concentration of the cell free-supernatant increased to 240 +/- 16 pg/ml, though the concentration was < 12.5 pg/ml without aCD30 Ab. In combination with aCD30 Ab, genistein decreased the concentration of IL-8 in day 5 supernatants. Although, doxorubicin and herbimycin-A suppressed [3H]TdR incorporation and induced apoptosis in the Ki-JK cells, they did not induce IL-8 secretion. Only aCD30 Ab-induced apoptosis was accompanied by IL-8 secretion. IL-8 mRNA was not detected in the Ki-JK cells by reverse transcription-polymerase chain reaction assay. IL-8 mRNA was detected 5 days after adding aCD30 Ab to the culture.

Antibodies↗
PubMed1998

Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa isolation from pharyngeal swab cultures among the Japanese elderly at admission to a geriatric hospital.

The isolation rate of Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa from pharyngeal swab cultures in the Japanese elderly was studied at admission to a geriatric hospital which had long-term care units. The subjects were 233 consecutive patients who were admitted to K Hospital in the time period April 1994 to March 1996. The isolation rate of MRSA and of Pseudomonas aeruginosa was 10.3% and 8.2% respectively. The proportions of the patients with severely to moderately limited Activities of Daily Living (ADL) (ADL score = 0-1) (P < 0.01), those with fever (P < 0.01), those with CRP positive (P = 0.04) and those with hypoalbuminemia (serum albumin < 3.5 g/dl) (P < 0.01) were higher in the MRSA positive patients than in the negative patients while the proportion of the patients with fever was higher in the Pseudomonas aeruginosa positive patients than in the negative patients (P < 0.02). In the multiple logistic regression analysis, the limitation of ADL (ADL score 0-1 vs 2-3, OR = 1.54, 95% CI = 1.02-2.33) and fever (with vs without, OR = 1.77, 95% CI = 1.18-2.66) remained as risk factors for the isolation of MRSA while only fever (with vs without, OR = 1.67, 95% CI = 1.11-2.53) remained as a risk factor for the isolation of Pseudomonas aeruginosa.

Activities of Daily Living↗
PubMed1998

Depression among caregivers of the elderly in need of care and their service utilization: a pilot study.

Twenty-four community residing elderly people in need of care, who were registered with the municipal welfare center in Miyagi Prefecture, Japan, and their principal caregivers participated in the study. The principal caregivers completed a self-administered questionnaire involving their demographic status, provided data on their utilization of formal services and completed the Center for Epidemiologic Studies Depression Scale (CES-D). The health visitors examined the activities of daily living (ADL) and mental status of these 24 elderly individuals. More than half the caregivers appeared to be depressed. The non-depressed caregivers used significantly more services than the depressed caregivers even after the caregivers' age was statistically controlled.

Aged↗
PubMed1998

Detraining effects on bone mass in young male rats.

The effects of exercise training and detraining on bone mass were assessed in young male Wistar rats. The rats were divided randomly into sedentary control (C) and exercise training (T) groups. The T rats were trained for 10 weeks followed by a 10-week detraining period. Training consisted of running exercise on a rodent treadmill at 35 m/min, +5-degree inclination, 60 min/day, 5 days/week. Training induced significant gain in fat-free dry weight and length of bones (femur, tibia, humerus and coxa) and bone mineral content (femur, tibia and humerus). Histological analysis at the tibial mid-shaft revealed a significant increase in total and cortical areas without a significant change in marrow area in the T group. Bone mass acquired through running exercise was retained for 10 weeks after cessation of training. These results indicate that running exercise leads to increased cortical bone associated with enhanced periosteal bone formation which is also maintained even after stopping exercise training, and suggest that training effects on the skeleton in bone mass level do not diminish immediately after cessation of training.

Absorptiometry, Photon↗
PubMed1998

Conservative management of acoustic neurinomas: prospective study of long-term changes in tumor volume and auditory function.

Recently reported retrospective analysis on the natural courses of acoustic neurinomas have disclosed that 26-86% of tumors show very slow, or no, growth for many years. To our knowledge, however, there have been no prospective analyses of the natural course of these tumors. We prospectively analyzed tumor growth as well as auditory function changes in 12 patients (13 tumors) managed conservatively. All 12 patients were advised to undergo both pure tone audiometry and magnetic resonance imaging at 3-4 month intervals for the first follow-up year and at 1-2 year intervals thereafter. Then, in the event of either significant tumor growth (> 20% volume increase) or hearing deterioration (> 10 dB), a decision would be made as to whether the patient should undergo either surgery or radiosurgery. A significant increase in tumor volume was confirmed in seven of the 13 tumors during the mean observation period of 564 days (88-1269 days). In another patient, though neither tumor growth nor worsening of auditory acuity was significant, the patient complained of subjective change in the symptoms. Therefore, we decided to treat eight (62%) of the 13 tumors. In contrast, neither tumor growth nor worsening of auditory acuity has as yet occurred in the remaining five tumors (38%) which have been observed for a mean period of 627 days (342-1377 days). Careful follow-up of these five patients is ongoing. Although further long-term follow-up is clearly necessary, conservative treatment appears to be a reasonable alternative to immediate treatment for selected patients with acoustic neurinomas.

Adult↗
PubMed1998

Developmental regulation of polysialic acid synthesis in mouse directed by two polysialyltransferases, PST and STX.

Polysialic acid is a developmentally regulated carbohydrate attached to the neural cell adhesion molecule, N-CAM, and abundant in embryonic tissues. There is increasing evidence that polysialic acid reduces N-CAM adhesion, thereby promoting neurite outgrowth and cellular mobility. It has been shown that two enzymes, polysialyltransferase, PST, and sialyltransferase X, STX, form polysialic acid on N-CAM. However, it is not known how these two enzymes contribute to polysialylation. In order to determine how the expression of PST and STX leads to polysialic acid synthesis during mouse development, the expression of PST and STX transcripts were evaluated by Northern blot analysis, competitive reverse transcription-polymerase chain reaction and in situ hybridization, and those results were correlated to the expression of polysialic acid. The results obtained by these analyses demonstrated that both PST and STX transcripts were barely detected at embryonic day 8 (E8) but increased after E9. PST and STX transcripts were present in substantial quantity between E11 and E15, coinciding with the period when maximum synthesis of polysialic acid is required. Ten days after birth, the level of STX transcript declined substantially, whereas the level of PST transcript only gradually declined and persisted in the adult brain. These results, taken together, strongly suggest that PST and STX coordinately synthesize polysialic acid during development. At the same time, they are expressed differentially in tissue-specific and cell-type-specific manners, suggesting that PST and STX may have distinct roles in development and organogenesis.

Animals↗
PubMed1998

Significance of free to total PSA ratio in men with slightly elevated serum PSA levels: a cooperative study.

BACKGROUND: The ratio of free PSA in total PSA (f/t) has been reported to improve the diagnostic accuracy of prostate cancer in the group with slightly elevated serum PSA values. In Japanese cases, the clinical significance of f/t is still controversial. METHODS: The diagnostic significance of f/t in serum for prostate cancer was evaluated in a cooperative study. A total of 77 cases with prostate cancer and 224 with non-prostate cancer showing less than 20 ng/ml of total PSA were evaluated. RESULTS: Serum total and free PSA values were not affected by storage at 25 degrees C for 2 days. The determination of f/t was useful in the cases with a serum total PSA of 5.1-10 ng/ml; the specificity was 60% with a sensitivity of 90% at an f/t of 0.148. The positive predictive value for diagnosis of prostate cancer also increased to 54% from 34% of that in total PSA alone. In the range of 4.1-10 ng/ml, the cut-off value of f/t was 0.155 for obtaining relatively high specificity; sensitivity was 85% and specificity was 56.5%. CONCLUSIONS: Thus, the determination of f/t was considered to be an effective tool for discriminating the non-prostate cancer cases from those of prostate cancer.

Humans↗
PubMed1998

Pharmacokinetics of soybean isoflavones in plasma, urine and feces of men after ingestion of 60 g baked soybean powder (kinako).

To take advantage of the various pharmacologic activities of soy bean isoflavones, more detailed studies of the absorption and excretion rates of these compounds in humans and subsequent evaluation of their bioavailabilities are required. We conducted a pharmacokinetic study of soybean isoflavones in seven healthy male volunteers. After ingestion of 60 g of kinako (baked soybean powder, containing 103 micromol daidzein and 112 micromol genistein), changes of the isoflavone and metabolite concentrations in plasma, urine and feces were measured by gas chromatography-mass spectrometry. The plasma concentration of genistein increased after 2 h and reached its highest value of 2.44 +/- 0.65 micromol/L 6 h later. The plasma concentration of daidzein peaked at 1.56 +/- 0.34 micromol/L at the same time, but it was always lower than that of genistein. Peak plasma concentration of O-desmethylangolensin (O-DMA) and equol appeared after the daidzein peak in four and two subjects, respectively. In contrast with plasma, daidzein was the main component in urine. Urinary daidzein excretion started to increase shortly after the rise in its plasma concentration and reached 2.4 micromol/h 8 h after ingestion of kinako. Genistein excretion in urine paralleled that of daidzein, but the value at 6 h was about half (1.1 micromol/h). The majority of ingested isoflavones after ingestion of kinako were recovered on d 2 or 3 in the feces. Total recovery of daidzein, O-DMA and equol from urine and feces was 54.7%, calculated from daidzein intake; 20.1% of administered genistein was recovered as genistein. The half-lives of plasma genistein and daidzein were 8.36 and 5.79 h, respectively. The individual plasma and urinary concentrations of equol and O-DMA were quite variable; subjects were classified as high and low metabolizers. The high plasma concentration of isoflavones for at least several hours after a single ingestion of soy protein suggests that these compounds may interact with macromolecules and have biological effects.

Absorption↗