Biomedical subjects

T Aoyama

Publications and source records attributed to T Aoyama.

At least 73 records · Page 4Linked to original sources

PubMed2000

Soy protein isolate and its hydrolysate reduce body fat of dietary obese rats and genetically obese mice (yellow KK)

This study examined in dietary obese and genetically obese rodents the effects of soy protein isolate (SPI) and its hydrolysate (SPI-H) on the rate of body-fat disappearance. Male Sprague-Dawley rats (4-16 wk old) and yellow KK mice (6-10 wk old) were made obese by feeding high-fat diets containing 30% fat. They were then fed energy-restricted, low-fat (5.0%), and high-protein (35% casein, SPI, or SPI-H) diets for 4 wk at 60% of the level of the energy intake of rodents on laboratory chow. The body-fat contents of rats and mice fed a high-fat diet were 27.3 and 33.6 g/100 g body weight, respectively, at the end of the obese period. For rats, the apparent absorbability of dietary energy and fat was significantly lower in the SPI and SPI-H groups than in the casein group, but vice-versa for nitrogen balance. Body-fat content in mice fed SPI and SPI-H diets was significantly lower than in those fed the casein diet. In rats, plasma total cholesterol level was lower with the SPI-H diet, and plasma glucose level was lower with the SPI and SPI-H diets than with the casein diet. These results indicate that SPI and SPI-H are suitable protein sources in energy-restricted diets for the treatment of obesity.

Adipose Tissue↗

PubMed2000

Elevation of transforming growth factor-beta1 is associated with recurrent miscarriage.

To investigate the significance of transforming growth factor-beta1 (TGF-beta1) in reproduction we have compared plasma levels in normal pregnant women and patients suffering miscarriages. We examined 188 normal pregnant women and 12 pregnant women with miscarriages. Eight women with severe recurrent miscarriages (mean +/- SD of previous number of miscarriages; 10.4 +/- 2.4 times) were also examined before conception; 34 nonpregnant women served as controls. Plasma TGF-beta1 level increased with the gestational week and returned within the normal range 1 month after delivery. The levels among pregnant women with miscarriages (mean +/- SD; 2.44 +/- 0.83 ng/ml) were significantly higher than those of pregnant controls (1.74 +/- 0.95 ng/ml) of matched gestational weeks; levels among nonpregnant women with severe recurrent miscarriages were extremely elevated (4.1 +/- 3.04 ng/ml) compared to the control value (1.34 +/- 0.59 ng/ml). These data suggest that TGF-beta1 may be necessary to maintain pregnancy but also may be a risk factor for recurrent miscarriages.

Abortion, Habitual↗

PubMed2000

Arabidopsis ARR1 and ARR2 response regulators operate as transcriptional activators.

The genes coding for the response regulators ARR1 and ARR2 have previously been identified by in silico screening of an expression sequence tag database and subsequent cloning from both Arabidopsis cDNA and genomic libraries. Their structures, in which the N-terminal signal receiver domain is followed by the output domain, are characteristic of typical bacterial response regulators of the two-component regulatory systems that control responses to a variety of environmental stimuli. Here we present evidence that these response regulators actually work as transcription factors. ARR1 and ARR2 were localized in the nuclei of plant cells regardless of the presence or absence of their signal receiver domain. Their middle segments, which faintly resemble the mammalian oncogene product Myb, were capable of binding double-stranded DNA in a sequence-specific manner in vitro. Their C-terminal halves functioned as transactivation domains in plant cells when combined with the DNA-binding domain of yeast GAL4. They thus possess all the essential components of a transcriptional activator. Both ARR1 and ARR2 promoted expression of a reporter gene in plant cells through their own target sequence. Truncation of their N-terminal signal receiver domain led to an increase in transactivation. An as yet unidentified phospho-relay signal may modulate the capability for transactivation and/or DNA binding through the signal receiver domain.

Arabidopsis↗

PubMed2000

Sex-dependent regulation of hepatic peroxisome proliferation in mice by trichloroethylene via peroxisome proliferator-activated receptor alpha (PPARalpha).

The mechanism of trichloroethylene-induced liver peroxisome proliferation and the sex difference in response was investigated using wild-type Sv/129 and peroxisome proliferator-activated receptor alpha (PPARalpha)-null mice. Trichloroethylene treatment (0.75 g/kg for 2 weeks by gavage) resulted in liver peroxisome proliferation in wild-type mice, but not in PPARalpha-null mice, suggesting that trichloroethylene-induced peroxisome proliferation is primarily mediated by PPARalpha. No remarkable sex difference was observed in induction of peroxisome proliferation, as measured morphologically, but a markedly higher induction of several enzymes and PPARalpha protein and mRNA was found in males. On the other hand, trichloroethylene induced liver cytochrome P450 2E1, the principal enzyme responsible for metabolizing trichloroethylene to chloral hydrate, only in males, which resulted in similar expression levels in both sexes after the treatment. Trichloroethylene influenced neither the level of catalase, an enzyme involved in the reduction of oxidative stress, nor aldehyde dehydrogenase, the main enzyme catalyzing the conversion to trichloroacetic acid. These results suggest that trichloroethylene treatment causes a male-specific PPARalpha-dependent increase in cellular oxidative stress.

Animals↗

PubMed2000

Effect of olprinone, phosphodiesterase III inhibitor, on cerebral blood flow assessed with technetium-99m-ECD SPECT.

Few clinical reports exist regarding the effects of phosphodiesterase III inhibitors on cerebral arteries. Therefore we used a [99mTc]-ECD brain SPECT and an ultrasound method to quantitatively evaluate cerebral and systemic flow dynamics after the administration of olprinone, a phosphodiesterase III inhibitor. In 15 patients (65 +/- 8 years, M/F = 13/2) with no abnormalities on a brain computed tomography (CT), cerebral blood flow and cardiac output were measured using [99mTc]-ECD brain SPECT and Doppler echocardiography, respectively. Measurements were repeated at baseline and after the administration of olprinone. Significant increases in cerebral blood flow (p = 0.0007) and cardiac output (p = 0.001) were observed, and systolic blood pressure (p = 0.02) and systemic vascular resistance (p = 0.002) significantly decreased. No significant correlation between the increase in cerebral blood flow and the increase in cardiac output was observed. The data indicate that olprinone has a direct vasodilator effect on the cerebral artery, which was little related to the increase in cardiac output in patients who had not experienced stroke.

Aged↗

PubMed2000

Experience with a strong bleaching treatment for skin hyperpigmentation in Orientals.

Although a variety of topical treatments have been used for skin hyperpigmentation, the effectiveness of each varies after prolonged treatment. In this study, 136 Oriental patients who were followed up for more than 12 weeks were analyzed. The treatment protocol was composed of two steps: bleaching (2 to 6 weeks) and healing (2 to 6 weeks); 0.1% to 0.4% all-trans retinoic acid aqueous gel was originally prepared and applied concomitantly with hydroquinone-lactic acid ointment for bleaching. After obtaining sufficient improvement of the hyperpigmentation, a corticosteroid was applied topically with hydroquinone and ascorbic acid for healing. Improvement was evaluated with a narrow-band reflectance spectrophotometer. The results were successful in more than 80 percent of cases of senile lentigines and postinflammatory hyperpigmentations, especially on the face. Sixty percent of cases of nevus spilus were also successfully treated. Although the transient adverse effects of this treatment may be more severe than conventional treatment, this strong bleaching protocol improves a variety of hyperpigmented lesions, including nevus spilus, with a higher success rate and a shorter treatment period than conventional protocols.

Administration, Topical↗

PubMed2000

Pharmacokinetic interactions among phenobarbital, carbamazepine, and valproic acid in pediatric Japanese patients: clinical considerations on steady-state serum concentration-dose ratios.

With antiepileptic drugs, the marked inter- and intrapatient variability of the concentration-dose ratio makes it difficult to predict serum concentrations from the dose administered per kilogram. The effects of comedication on steady-state serum concentration/dose ratios of antiepileptic drugs were evaluated retrospectively in 669 pediatric patients. To avoid complex pharmacokinetic interactions among multiple antiepileptic drugs, the data on serum concentrations in the current study were collected from patients who were co-administered only one additional antiepileptic drug (phenobarbital-carbamazepine, phenobarbital-valproic acid, or carbamazepine-valproic acid) or who received monotherapy. The concentration/dose ratio for the antiepileptic drugs increased significantly with body weight in children up to 15 years old. Associated therapy with antiepileptic drugs affected the concentration/dose ratio. Therefore, routine monitoring of serum concentrations of the antiepileptic drugs is extremely useful, particularly in children and in patients who require associated antiepileptic medication.

Adolescent↗

PubMed2000

Echocardiographic observation of acute myocarditis with systemic lupus erythematosus.

Although myocarditis from a series of autopsies of patients with systemic lupus erythematosus was frequently observed, the incidence of clinically apparent myocardial dysfunction was low. A 30-year-old woman with systemic lupus erythematosus was examined by echocardiography. An acoustic densitometry was followed at the left ventricular posterior wall throughout the clinical course. A decrease in the magnitude of cyclic variation of integrated backscatter (IB) was observed before treatment. Following the combined treatment, steroid and cyclophosphamide, a repeated ultrasonic tissue characterization showed an increase in the magnitude of cyclic variation of IB. It is thought that ultrasonic tissue characterization may be a useful method to evaluate the impairment of contraction, and to follow up the clinical course of myocardial involvement in systemic lupus erythematosus.

Adult↗

PubMed2000

Effect of soy and milk whey protein isolates and their hydrolysates on weight reduction in genetically obese mice.

The effect on genetically obese mice of a milk whey protein isolate (WPI) and soy protein isolate (SPI) and their hydrolysates (WPI-H, SPI-H) on the rate of body fat disappearance was investigated. Male yellow KK mice were made obese by feeding with a high-fat diet containing 30% fat from 6 to 10 weeks of age. They were then fed with an energy-restricted low fat (5.0%) and high protein (35% WPI, WPI-H, SPI or SPI-H) diet for 2 weeks at the 60% level of energy intake by mice on laboratory feed. During the weight reduction period, the body weight of the WPI, WPI-H, SPI and SPI-H groups changed by -9.1, -9.1, -10.0 and -11.1 g/14 days, respectively, the reduction being significantly lower in the SPI-H group than in the WPI and WPI-H groups. The plasma total cholesterol level was significantly lower with the SPI diet, and the plasma glucose level was lower with the SPI and SPI-H diets than with the WPI and WPI-H diets. Although the body protein content was comparable in all the groups, the body fat content was significantly lower with the SPI diet than with the WPI diet, and was also significantly lower with the SPI-H diet than with the WPI and WPI-H diets. The weight of the perirenal fat pads was significantly lower with the SPI-H diet than with the WPI and WPI-H diets. These results indicate that SPI and SPI-H are suitable protein sources in an energy-restricted diet for treating obesity.

Adipose Tissue, Brown↗

PubMed2000

Acyl-CoA thioesterases belong to a novel gene family of peroxisome proliferator-regulated enzymes involved in lipid metabolism.

Acyl-CoA thioesterases hydrolyze acyl-CoAs to the corresponding free fatty acid plus coenzyme A. The activity is strongly induced in rat and mouse liver after feeding the animals peroxisome proliferators (PPs). To elucidate the role of these enzymes in lipid metabolism, the authors have cloned the cDNAs corresponding to the inducible cytosolic and mitochondrial type I enzymes (CTE-I and MTE-I), and studied tissue expression and nutritional regulation of expression of the mRNAs in mice. The constitutive expression of both mRNAs was low in liver, with CTE-I expressed mainly in kidney and brown adipose tissue, and MTE-I expressed in brown adipose tissue and heart. As expected, the expression in liver of both the CTE-I and MTE-I mRNAs were strongly induced (> 50-fold) by treatment with clofibrate. A similar level of induction was observed by fasting and a time-course study showed that the CTE-I and MTE-I mRNAs were increased already at 6 h after removal of the diet. Refeeding normal chow diet to mice fasted for 24 h normalized the mRNA levels with a T1/2 of about 3-4 h. Feeding mice a fat-free diet further decreased the expression, possibly indicating repression of expression. The strong expression of MTE-I and CTE-I in the heart was increased about 10-fold by fasting. To further characterize these highly regulated enzymes, the authors have cloned the corresponding genes and promoter regions. The structures of the two genes were found to be very similar, consisting of three exons and two introns. Exon-intron borders conform to general consensus sequences, and, especially, the first exon appears to be highly conserved. The promoter regions of both the CTE-I and MTE-I genes contain putative PP response elements, suggesting an involvement of PP-activated receptors in the regulation of these genes.

Amino Acid Sequence↗

PubMed2000

Polymorphism of drug-metabolizing enzymes in relation to individual susceptibility to industrial chemicals.

Polymorphism and the induction/inhibition of drug-metabolizing enzymes, such as cytochrome P450, aldehyde dehydrogenase (ALDH), glutathione S-transferase (GST), N-acetyltransferase (NAT), and NAD(P)H-quinone oxidoreductase (NQO1), were reviewed in relation to susceptibility to disease and to inter-individual difference in biological monitorings. A number of genetic and acquired factors can influence the susceptibility of an individual to chemicals, creating a so-called predisposition. Most cases in which genetic factors were present resulted from polymorphism of drug-metabolizing enzymes. However, conflicting reports have appeared on the relationship between polymorphism and risk of disease; in some cases, biologically plausible mechanisms linking genotypes and disease are not yet in evidence. Current findings based on biological monitoring of chemicals are insufficient to evaluate the relationship between genetic polymorphism and acquired risk when exposure has occurred in an occupational area. Investigation of such situations has generated data implicating GSTT1, GSTM1, NAT2, and NQO1 polymorphisms in biological monitoring of some chemicals; the ALDH2 polymorphism is the likely link between the genotype and the metabolism of low molecular aliphatic aldehydes. Although this polymorphism is limited in the case of Japanese as well as other Asian subjects, the inhibitors of ALDH2 activity such as trichloroethylene may produce a false polymorphism of this gene. As to the effect of factors influencing acquired predisposition, such as ethanol intake, intake of low carbohydrate diet or diabetes, corroborative epidemiological studies may be further required.

Aldehyde Dehydrogenase↗

PubMed2000

Volume-weighted mean nuclear volume. Is this new prognosticator comparable in different institutions?

OBJECTIVE: To determine whether volume-weighted mean nuclear volume (MNV) obtained at one institution is comparable to that from other institutions. STUDY DESIGN: MNV calculated from histologic slides obtained at three hospitals--Shizuoka Prefectural Hospital (SPH), Shimada Municipal Hospital (SMH) and Shizuoka City Hospital (SCH)--were compared. Between December 1994 and June 1996, transurethral resection of bladder tumor or transurethral resection of the prostate was performed on 37 patients at SPH and 50 patients at SMH; histologic specimens from 40 cases of bladder tumors, 63 cases of normal bladder mucosa, 28 cases of benign prostatic hyperplasia and 1 case of prostate cancer were obtained. A portion of each specimen obtained at SPH or SMH was carried to SCH, and histologic slides were made at SCH using it. Using the remaining position of each specimen, histologic slides were then prepared at each hospital. Estimates of MNV were made from all histologic slides from each hospital, and the differences in MNV between the hospitals were analyzed. In addition, intraobserver and interobserver reproducibility were analyzed using 50 specimens obtained between December 1994 and August 1995. RESULTS: On linear regression analysis, comparison of MNVs calculated from the histologic slides from SPH and SCH and those calculated from SMH and SCH revealed high correlation coefficients (R = .966 and .966, respectively), and the slope of the regression line did not differ significantly from unity. The paired t test also disclosed no significant difference between MNVs calculated at the two hospitals. Furthermore, the correlation coefficients for intraobserver and interobserver reproducibility of MNV estimates were also high (R = .918 and .949, respectively). CONCLUSION: The results of this study indicate that estimates of MNV are comparable in multiple institutions, and we recommend that they be used to support subjective histologic grading.

Cell Nucleus↗

PubMed2000

[Successful aortic root replacement for prosthetic valve endocarditis using the freestyle stentless bioprosthesis: report of two cases].

We report two cases of prosthetic valve endocarditis which were successfully treated with aortic root replacement using the freestyle stentless bioprosthesis. Prosthetic valve endocarditis occurred in two patients after aortic valve replacement and modified Bentall operation, respectively. The aortic annulus was severely damaged and left ventriculo-aortic discontinuity was found in both cases. We used the freestyle stentless bioprosthesis, which fits well to the destroyed aortic annulus with left ventriculo-aortic discontinuity, because of its flexibility. Postoperative echocardiography revealed excellent hemodynamic results in both cases. Although the long-term results obtained with the freestyle stentless bioprosthesis, such as resistance to bacterial infection, have not been reported, this prosthesis appears to be very useful for treatment of prosthetic valve endocarditis. We expect that this prosthesis might be a option for PVE as an alternative to a homograft.

Adult↗

PubMed2000

[Catastrophic pulmonary vasoconstriction associated with protamine reversal of heparin].

Administration of protamine intravenously to neutralize the anticoagulant effects of heparin may be associated with hypotension. These adverse cardiovascular responses to protamine fall into three distinct types: transient hypotension related to rapid drug administration; anaphylactic responses: and catastrophic pulmonary vasoconstriction. We recently observed three patients who had catastrophic pulmonary vasoconstriction, which were treated with the assist circulation and intraaortic balloon pumping. The two patients were survived except one who was dead due to the cerebral ischemic damage which was introduced by delayed establishment of circulatory assist device. We conclude that meticulous longstanding observation of the hemodynamic condition is important after administration of protamine under the unremoved cannulations.

Aged↗

PubMed2000

[Surgical treatment for infective endocarditis with multiple embolic complications].

A 59-year-old man was transferred to our hospital because of severe right leg pain, dyspnea and anuria. Due to severe cyanosis of the legs below the knees and severe hyperkalemia, he had undergone embolectomy of the right femoral artery and hemodialysis. Medical treatment for infective endocarditis was started after the first operation, because transesophageal echo cardiography revealed severe aortic regurgitation and massive vegetation of the aortic valve. Amputation of the right leg below the knee and of the left leg below the Lisfranc joint was performed after 19 days and aortic valve replacement with patch closure of a perivalvular abscess was performed one month after the first operation. The post-operative course was uneventful. He was weaned from hemodialysis and the follow-up echocardiographic study revealed no vegetation.

Abscess↗

PubMed2000

[Bellini duct carcinoma of the kidney: a case report].

This is a report of a case of Bellini duct carcinoma of the kidney. A 72-year-old male was admitted to our hospital for the treatment of left renal tumor. The abdominal computed tomographic scan showed hypoattenuating tumor with infiltrative spread into the renal cortex. The renal angiography revealed a hypovascular tumor. Left nephro-ureterectomy was performed because transitional cell carcinoma was suspected in the frozen section. The gross examination revealed an infiltrating white-gray tumor centered in the renal medulla. No hemorrhage was discovered, but partial necrosis was found. Capsular infiltration was not seen. Histologically, tumor cells were mostly scattered and partially showed a papillary and tubular structure. Cells had abundant eosinophilic cytoplasm and large irregular nuclei. Immunohistochemical studies revealed positive reactions for cytokeratin, epithelial membrane antigen and ulex europaeus agglutinin. We diagnosed this patient with Bellini duct carcinoma. He died due to drastic progression of metastasis from carcinoma two months postoperatively.

Aged↗

PubMed1999

A functional and quantitative mutational analysis of p53 mutations in yeast indicates strand biases and different roles of mutations in DMBA- and BBN-induced tumors in rats.

In order to analyze the mutational events and to understand the biological significance of the p53 gene in chemical carcinogenesis, we applied a new yeast-based p53 functional assay to ovarian tumors induced by 7, 12-dimethylbenz[a]anthracene (DMBA), as well as to transitional cell carcinomas of the urinary bladder induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in rats. The assay demonstrated that 15 of 19 DMBA induced tumors harbored clonal p53 mutations, which is consistent with the expectations of the "clonal expansion" hypothesis. The majority of the mutations were purine (AG) to pyrimidine (CT) transversions (12/19) on the non-transcribed (sense) strand (NTS), which is likely to be due to depurination created by DMBA adduct formation on the NTS. In contrast, we found no pyrimidine to purine [corrected] transversion on the NTS. After cessation of BBN treatment, BBN-induced multifocal lesions in the bladder contained heterogeneous p53 mutations at an early stage. In the later stage, however, clonal p53 mutations were identified in 4 out of 7 bladders analyzed, conforming with the concept of "field cancerization". The observed base substitutions were G-->A (1/6) or C -->T transitions (2/6), and mutations at T (3/6) on the NTS in clonal mutations, together with non-clonal mutations, showing a preference of C-->T to G-->A (17 vs. 0). Thus, preferential repair was found in the transcribed strand of the p53 gene, whether modified by DMBA or by BBN carcinogens. Very similar mutation patterns were observed between clonal and non-clonal mutations in the DMBA- and BBN-induced tumors, indicating that the rat yeast p53 functional assay can be a potential tool for the characterization of in vivo mutation patterns of p53, when modified by chemical carcinogens.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1999

Significance of myocytes with positive DNA in situ nick end-labeling (TUNEL) in hearts with dilated cardiomyopathy: not apoptosis but DNA repair.

BACKGROUND: The presence of apoptotic myocytes has been reported in human hearts with dilated cardiomyopathy (DCM) on the basis of a positive finding of DNA in situ nick end-labeling (TUNEL). However, ultrastructural evidence of myocyte apoptosis has not been obtained. METHODS AND RESULTS: A total of 80 endomyocardial biopsies were obtained from right and left ventricles of 20 patients with DCM and 20 normal control subjects. TUNEL-positive myocytes were found by light microscope in 15% of DCM specimens (controls, 0%, P<0.05), and the percentage of TUNEL-positive myocytes per section in DCM was 1. 0+/-2.7% (mean+/-SD). According to TUNEL at the electron microscopic level (EM-TUNEL), immunogold particles, which label DNA breaks with 3'-OH terminals, were markedly accumulated in the bizarre-shaped nuclei, with widespread clumping of chromatin (so-called "hypertrophied nuclei") of the myocytes obtained from DCM. Their ultrastructure was neither apoptotic nor necrotic but rather that of living cells. Taq polymerase-based DNA in situ ligation assay, which detects double-stranded DNA fragments more specifically than TUNEL, did not detect a positive reaction in any case. In mirror sections, all of the TUNEL-positive myocytes in DCM simultaneously expressed proliferating cell nuclear antigen, which is required for both DNA replication and repair, but Ki-67, a replication-associated antigen, was completely negative in all cases, which appeared to rule out cell proliferation activity. CONCLUSIONS: Most of the TUNEL-positive myocytes in hearts with DCM are not apoptotic but rather living cells with increasing activity of DNA repair.

Apoptosis↗