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Biomedical subjects

T Aoki

Publications and source records attributed to T Aoki.

At least 55 records · Page 3Linked to original sources
PubMed2003

The clinical significance of sialyl Lewis antigen expression in the spread of gastric cancer. Flow cytometric DNA analysis.

We previously reported significant relationships between sialyl Lewis antigen expression on gastric cancer cells and both hepatic metastasis and clinical prognosis. The purpose of this study was to compare the expression of sialyl Lewis antigens on gastric cancer cells to elucidate the possible role of sialyl Lewis antigens in predicting the spread of a tumor with regard to histological findings. Subjects consisted of 38 patients with gastric cancer. For comparison we measured the values for sialyl Lewisa (sLea) and sialyl Lewisx (sLex) expression on the surface of about 10,000-30,000 cancer cells. Monoclonal antibodies CA19-9 and KM-93 were used to determine the frequency (%) and quantity (channel) of the expression by flow cytometry. We assessed the correlation of sLea and sLex expression with histological findings (depth of tumor invasion (pT), lymphatic invasion (ly), venous invasion (v), and lymph node metastasis (pN)), by comparing sLea and sLex expression in relation to the grade of histological findings. A significant relationship was found between lymphatic invasion and the frequency of sLea expression (r = 0.40, p<0.05). The mean values of sLea frequency in cases categorized as ly 2 (36.30) and ly 3 (31.81) were statistically higher than those in ly 1 cases (12.74) (p<0.05). A significant relationship was also observed between lymph node metastasis and the frequency of sLea expression (r = 0.46, p<0.01). The mean value of sLea frequency in pN 3 cases (44.14) was statistically higher than those in pN 0 (17.11) and pN 1 (19.03) cases (p<0.05). Neither the depth of tumor invasion nor venous invasion showed any correlation with the expression of sialyl Lewis antigens. In conclusion the frequency of sLea expression on the surface of gastric cancer cells was greater in those patients who developed lymphatic invasion and lymph node metastasis. However, the mechanism by which sialyl Lewisa expression is upregulated remains unclear.

Adult↗
PubMed2003

A study on angiogenesis-related matrix metalloproteinase networks in primary hepatocellular carcinoma.

Matrix metalloproteinases (MMPs) specially degrade extracellular matrix (ECM) proteins and are involved in tissue remodeling and angiogenesis. Therefore, studies on the role of MMPs in the carcinogenesis, proliferation and infiltration of hepatocellular carcinoma (HCC) may greatly contribute to the development of a new clinically applicable therapeutic approach. In the present study, we immunologically examined the expression rates of various MMPs including MMP-2, 3, 7, 9, membrane type 1-MMP (MT1-MMP), and MT2-MMP in the cancerous and noncancerous areas of resected tumor specimens from 30 patients with primary HCC. The rate of MMP-2 expression was high for both cancerous and noncancerous areas. However, the expression rates of MMP-3, MT1-MMP, and MT2-MMP were significantly higher in cancerous areas than in noncancerous areas. Next, we examined the clinicopathologic features such as the number of tumor nodules, maximal tumor size, presence or absence of capsular infiltration and portal vein invasion, histological grades of HCCs, state of noncancerous areas (chronic hepatitis: CH or liver cirrhosis: LC), and short-term recurrence after resection (within six months). In conclusion, it was found that three main networks of MMPs are predominantly involved in the case of HCC, that is, MMP-2 and MT1-MMP in the carcinogenesis and progression, MMP-7 and MMP-9 in the capsular infiltration and portal vein invasion, as well as MMP-3 and MMP-7 in the progression of HCC. Furthermore, MT1-MMP appeared to be the most important factor in HCC because of its widespread pattern of expression.

Carcinoma, Hepatocellular↗
PubMed2002

Extremely low vertical-emittance beam in the accelerator test facility at KEK.

Electron beams with the lowest, normalized transverse emittance recorded so far were produced and confirmed in single-bunch-mode operation of the Accelerator Test Facility at KEK. We established a tuning method of the damping ring which achieves a small vertical dispersion and small x-y orbit coupling. The vertical emittance was less than 1% of the horizontal emittance. At the zero-intensity limit, the vertical normalized emittance was less than 2.8 x 10(-8) rad m at beam energy 1.3 GeV. At high intensity, strong effects of intrabeam scattering were observed, which had been expected in view of the extremely high particle density due to the small transverse emittance.

Journal Article↗
PubMed2002

Machinability of cast commercial titanium alloys.

This study investigated the machinability of cast orthopedic titanium (metastable beta) alloys for possible application to dentistry and compared the results with those of cast CP Ti, Ti-6Al-4V, and Ti-6Al-7Nb, which are currently used in dentistry. Machinability was determined as the amount of metal removed with the use of an electric handpiece and a SiC abrasive wheel turning at four different rotational wheel speeds. The ratios of the amount of metal removed and the wheel volume loss (machining ratio) were also evaluated. Based on these two criteria, the two alpha + beta alloys tested generally exhibited better results for most of the wheel speeds compared to all the other metals tested. The machinability of the three beta alloys employed was similar or worse, depending on the speed of the wheel, compared to CP Ti.

Alloys↗
PubMed2002

Differential expression of two tumor necrosis factor genes in rainbow trout, Oncorhynchus mykiss.

A second TNF gene (TNF2) has been cloned and sequenced in rainbow trout. In common with the first TNF gene isolated (TNF1), this gene is more TNF alpha-like than TNF beta-like. The full length cDNA is 1519bp, containing a 765bp open reading frame. The gene has four exons, of 380, 49, 60 and 1030bp, respectively. Analysis of the 5' flanking regions of TNF1 and TNF2 reveals several interesting differences in identified transcriptional regulatory elements, with a CATAAA box present 26bp upstream of the transcription start in both genes. Expression analysis in LPS stimulated macrophages has shown a much stronger expression of TNF2 relative to TNF1, with expression being detected earlier and lasting longer.

Amino Acid Sequence↗
PubMed2002

DNA damage and the effect of antioxidants in streptozotocin-treated mice.

Streptozotocin (STZ) has drawn attention as a potential source of oxidative stress, which induces genotoxicity. We investigated the effects of STZ on DNA damage in the liver and kidney, as well as the protective effects of antioxidants, by using the alkaline single-cell gel electrophoresis assay, and by measuring the ratio of 8-hydroxy-2'-deoxyguanosine (8-OHdG) to dG. A single intraperitoneal injection of STZ (150 mg/kg) increased serum levels of glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and blood urea nitrogen (BUN), and also caused DNA damage in the liver and kidney, which recovered slowly with time. Antioxidants,(ascorbic acid, trolox and probucol) prevented the STZ-induced elevation of DNA damage in the liver and kidney and inhibited the increase in serum levels of AST, ALT and BUN. Thus ascorbic acid, trolox, and probucol protected the mice against STZ-induced DNA damage that might contribute to the development of hepatic or renal disease.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2002

Antioxidative effects of fluvastatin and its metabolites against DNA damage in streptozotocin-treated mice.

Fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, and its metabolites have been reported to protect against oxidative DNA damage in vitro. Streptozotocin (STZ) has drawn attention as a potential source of oxidative stress that induces genotoxicity. In order to elucidate the antioxidative effects of fluvastatin in vivo, we investigated the effects of 7-day treatment with fluvastatin on DNA damage in STZ-treated mice, as well as the effects of the main fluvastatin metabolites (M2, M3 and M4) and other inhibitors of the same enzyme, pravastatin and simvastatin. Protective effects against DNA damage in the liver and kidney from STZ-treated mice were assessed by the single-cell gel electrophoresis assay, and by detecting 8-hydroxy-2'-deoxyguanosine. A single intraperitoneal injection of STZ (150 mg/kg) increased serum levels of glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and blood urea nitrogen (BUN), and also caused DNA damage in the liver and kidney. Fluvastatin and its metabolites prevented the STZ-induced elevation of DNA damage and inhibited the increase in serum levels of AST, ALT and BUN. Fluvastatin and its metabolites showed protective effects against DNA damage as potent as that of the reference antioxidants (ascorbic acid, trolox and probucol) though pravastatin and simvastatin still lacked protective activity. Fluvastatin protected the mice against STZ-induced DNA damage, and may reduce the risk of oxidative stress in vivo.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2002

Abnormal distributions of callosal commissural and corticothalamic neurons in the cerebral neocortex of Shaking Rat Kawasaki.

Shaking Rat Kawasaki (SRK) is an autosomal recessive mutant rat recognized by unstable gait and tremor and by early death around the time of weaning. We previously reported that corticospinal tract neurons are malpositioned in the motor cortex of the SRK rat [Ikeda and Terashima (1997) J. Comp. Neurol. 383, 370-380]. In the present study, we examined the distribution pattern of callosal commissural (CC) and corticothalamic (CT) neurons of SRK and normal rats with the injection of horseradish peroxidase (HRP) into the contralateral hemisphere or wheat germ agglutinin-conjugated HRP into the ventral lateral thalamic nucleus. The intracortical distribution pattern of retrogradely labeled CC and CT neurons in the motor cortex of SRK rat was abnormal: CC neurons were more deeply situated and CT neurons were more superficially situated in the SRK cortex than the corresponding components in the normal cortex. Most of labeled CC and CT neurons had abnormal dendritic configurations. Statistical analysis revealed that the difference of the mean intracortical position of CC and CT neurons of the SRK was significantly different from the normal counterparts (Student's t-test, P<0.01). Taken together with previous findings, our data demonstrate that the abnormal cytoarchitecture of SRK cortex resembles the reeler cortex.

Agenesis of Corpus Callosum↗
PubMed2002

Significant decrease of the International Index of Erectile Function in male renal failure patients treated with hemodialysis.

In order to evaluate the erectile function in male renal failure patients treated with hemodialysis (HD), we investigated the International Index of Erectile Function (IIEF) in patients and healthy controls. The subjects were 174 male patients treated with HD, of whom 43 had diabetes mellitus (DM) and the remaining 131 patients did not have DM. The controls were 1133 healthy males. We evaluated the prevalence of erectile dysfunction (ED) using the erectile function (EF) score, which is one of the five domains of the IIEF, in each age group (upto 39 y old, 40-49 y old, 50-59 y old, 60-69 y old). The severity of ED was classified into five categories using EF in each age group. The univariate logistic regression analysis and multiple variate analysis of IIEF in HD patients were performed. The prevalence of ED in HD patients was significantly higher than that in the controls in each age group. The severity of ED in HD patients was also significantly higher than that in the controls in each age group. In the logistic regression analysis and multiple variate analysis of IIEF in HD patients, DM and age were significant risk factors on sexual dysfunction. ED was more prevalent in male renal failure patients treated with HD than in the controls. In the patient group, ED was more prevalent in older DM patients.

Adult↗
PubMed2002

Erythrocyte aldose reductase correlates with erectile dysfunction in diabetic patients.

Erectile dysfunction (ED) is a common complication of diabetes mellitus. Erythrocyte aldose reductase (AR) has been implicated in a variety of diabetic complications. The subjects were 62 diabetic patients, of whom 25 were treated with hemodialysis (chronic renal failure CRF group) and the remaining 37 did not have chronic renal failure (DM group). The controls were 20 healthy volunteers age-matched to the patients. The level of AR was measured by the quantitative determination kit for AR in all patients and controls. In this study, ED was diagnosed by 5-item version of the International Index of Erectile Function (IIEF-5). The average level of AR in the CRF group was significantly higher than that in the DM group and controls (P<0.001). The average level of AR in the DM group without ED was significantly lower than that in the DM group with ED and controls (P<0.005). These results suggest that the level of AR may be a useful modality for prediction of ED in diabetic patients.

Aged↗
PubMed2002

Cell cycle-regulated factors in esophageal cancer.

Alterations of cell cycle-regulated genes play an important role in the process of carcinogenesis, and some of them are thought to be prognostic factors in esophageal cancer. The expressions of p53, p16, pRB and Cyclin D1 proteins were evaluated immunohistochemically in 144 patients who underwent curative esophagectomy without any adjuvant therapy before surgery. p53 overexpression was observed in 99 (69%) out of the 144 patients. No significant correlation was noted between p53 and any other gene expression. p16 expression was observed in 12 (8.3%) out of all cases. A negative correlation was recognized between p16 and Cyclin D1 expression (P=0.0004). pRB expression was observed in 130 (90.3%) out of all cases, whereas pRB expression was not observed in 11 out of the 12 patients with p16-positive tumors. A negative correlation was also found between p16 and pRB (P < 0.0001). A positive correlation was noted between pRB and Cyclin D1 expression (P=0.0009). The cumulative survival rate of patients without pRB expression was significantly lower than that of patients with positive expression (P=0.003). In the multivariate survival analysis, pRB expression was an independent prognostic factor. In 98% of all patients with esophageal cancer, impairment of the G1 checkpoint is due to a loss of function by p16, pRB or Cyclin D1, which showed a negative correlation in each factor. In addition, aberrant expression of pRB is useful as a prognostic factor in esophageal cancer.

Adult↗
PubMed2002

Macular configuration determined by optical coherence tomography after idiopathic macular hole surgery with or without internal limiting membrane peeling.

AIMS: To evaluate the effect of pars plana vitrectomy (PPV) with or without internal limiting membrane (ILM) peeling on the closure and configuration of idiopathic macular holes (IMH). METHODS: PPV was performed for IMH on 44 eyes with ILM peeling (ILM peeled group) and on 42 eyes without ILM removal (ILM preserved group). Optical coherence tomography (OCT) was performed on 34 ILM peeled eyes and 14 ILM preserved eyes after successful surgery. The repaired macular holes were classified by the OCT images as being of "good shape" (nearly normal foveal contour) or "poor shape" (abnormal foveal contour with flat fovea and steep edge, or with a thick retina without a foveal pit). RESULTS: The anatomical closure rate was significantly higher in the ILM peeled group (93.2%) than in the ILM preserved group (76.2%) (p = 0.028). In the ILM peeled group, 31 eyes had a fovea of good shape and three eyes had a fovea with a poor shape, while in the ILM preserved group, six eyes had a fovea of good shape and eight eyes had a fovea of poor shape. The percentage of eyes with good macular configuration in the ILM peeled group was significantly higher than in the ILM preserved group (p = 0.0003). No significant difference was found in the postoperative visual acuity and the increase of visual acuity between the ILM peeled group and the ILM preserved group (p = 0.26, and p = 0.91 respectively). There was also no significant difference in the postoperative visual acuity and improvement in visual acuity between eyes with a fovea of good shape and those with fovea of poor shape fovea (p = 0.99 and p = 0.66, respectively). CONCLUSIONS: ILM peeling may provide better anatomical success and recovery of the macular shape, but the postoperative visual acuity and improvement of visual acuity were not related to the morphological results.

Aged↗
PubMed2002

Catheter dysfunction and thrombosis of double-lumen hemodialysis catheters placed in the femoral vein.

OBJECTIVE: Intraluminal thrombosis of the catheter was thought to be a major cause of catheter dysfunction. We evaluated if thrombi appear in the luminal side or outside of the catheters placed in the femoral vein in 21 hemodialysis patients. METHODS: 23 double-lumen catheter (25 cm long and 4 mm diameter polyurethane) strippings were consecutively performed. Mean catheter dwell time was 17.9 +/- 11.2 days (2-45 days). The femoral vein was observed with ultrasound echography, and thrombo-venous ratio (thrombus diameter/vein diameter) was calculated. X-rays were also taken to clearly visualize the thrombi followed by contrast medium injection through the catheter. RESULTS: Tube-shaped thrombi were echographically detected in 22 of 23 catheters (95.7%) when the catheter was stripped. Ten catheters (43.5%) were stripped due to the reduced blood flow, and tube-shaped thrombi were observed in the femoral vein, whereas no thrombus was found in the intraluminal side of the catheter. In 7 of 23 patients (30.4%) with leg edema on the same side of the catheter, the thrombovenous ratio was 78.9 +/- 7.4%, which was higher than that in the patients without leg edema (52.1 +/- 11.1%). CONCLUSION: The tube-shaped thrombi, formed around the double-lumen catheter, may cause catheter dysfunction and reduced venous return of the lower legs. The catheter should be removed as soon as thrombosis is diagnosed, especially when accompanied by leg edema.

Aged↗
PubMed2001

Temporal and force characteristics of fast double-finger, single-finger and hand tapping.

The purposes of this study were: (1) to provide descriptive temporal and force data for fast alternate tapping by the index and middle fingers ('double-finger mode'), and to compare it with one finger fast tapping ('single-finger mode'); (2) to determine any differences in the dynamic motor function of individual fingers with these tapping tasks; and (3) to determine any differences between the single-finger mode and tapping with the whole hand ('hand mode'). Eleven healthy males tapped force transducer(s) for 7 s as fast as possible using their dominant hand. The double-finger mode had a greater peak force and a 50% faster tapping frequency than the single-finger mode. There was no correlation between the single-finger and double-finger modes in the temporal data. Tapping with two fingers thus seems to be organized with a motor strategy that is different from that with one finger, and can possibly capture an individual's additional or different motor function. A comparison between the two fingers revealed that the index finger had a significantly faster tapping frequency, indicating the superiority of the index finger over the middle finger in terms of dynamic motor function. The hand mode had a significantly faster tapping frequency with greater peak force than the single-finger mode. A distinction is essential between these two modes.

Adult↗