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Biomedical subjects

T Yamasaki

Publications and source records attributed to T Yamasaki.

At least 19 recordsLinked to original sources
PubMed2006

Clinical and endoscopic characterization of depressed gastric adenoma.

BACKGROUND AND STUDY AIM: Depressed gastric adenoma remains poorly characterized because it is rare, and is infrequently detected by endoscopy. The aim of this study was to elucidate clinical and endoscopic characteristics of depressed adenoma of the stomach. PATIENTS AND METHODS: 95 consecutive patients who underwent endoscopic resection of gastric adenomas were studied. Gastric adenomas, diagnosed according to the Vienna classification, were endoscopically classified into two types: depressed and protruding adenomas. In order to clarify endoscopic features of gastric adenomas, we performed indigo carmine chromoendoscopy as well as magnifying endoscopy with narrow band imaging, which yields clear images of mucosal microvasculature. RESULTS: 12% of 100 gastric adenomas resected from 95 patients were depressed adenomas. Age and gender were comparable between patients with each type. Depressed adenomas (15.9 +/- 6.2 mm) were significantly larger in diameter than protruding adenomas (10.6 +/- 8.0 mm) (P = 0.01). Half of depressed adenomas were reddish in color, whereas only 18% of protruding adenomas were reddish. Magnifying endoscopy with narrow band imaging showed that 71% of depressed adenomas had a regular ultrafine network pattern of mucosal microvasculature, which was not seen in protruding adenomas. Intramucosal carcinomas were more frequently found in depressed adenomas (25%) than in protruding adenomas (4.5%). CONCLUSIONS: In comparison with protruding adenomas, depressed adenomas were rare and appeared endoscopically as large and reddish with a specific regular ultrafine network pattern of mucosal microvasculature. Depressed adenomas should be endoscopically resected because intramucosal carcinomas were found in a quarter of them.

Adenoma↗
PubMed2005

Curved varus femoral osteotomy for minimal dysplastic hip in patients older than 45 years of age: comparison with rotational acetabular osteotomy.

Periacetabular osteotomies, such as rotational acetabular osteotomy (RAO) for osteoarthritis (OA) secondary to hip dysplasia, have produced satisfactory medium- and long-term results in early OA. However, as the degree of surgical invasion of these procedures is comparatively major and long-term postoperative rehabilitation is required, this procedure is generally not indicated for those in the fifth and sixth decades of life. Curved varus femoral osteotomy (CVO), which is a less invasive procedure, is considered a worthwhile option, although to the best of our knowledge no comparative study has been reported on these two procedures in older patients. We performed a comparative study on the outcomes of CVO for minimal dysplasia of the hip with a center-edge (CE) angle greater than 5 degrees in 15 patients (15 joints) older than 45 years of age at a mean period of 8 years after surgery and on the outcomes of RAO in 16 patients (18 joints) performed during the same period. No significant difference was observed between the two groups regarding the Merle d'Aubigne score during follow-up. Progression of osteoarthritis was radiologically observed during follow-up in three hips in the CVO group and in one hip in the RAO group. Kaplan-Meier survivorship analysis, with radiological progression of osteoarthritis as the endpoint, predicted a survival rate of 75% at 10 years in the CVO group. In the RAO group the predicted 10-year survival rate was 94%, demonstrating no significant difference between the two groups. CVO is a less invasive surgical technique than RAO, requires a comparatively shorter period of postoperative rehabilitation, and is useful as a joint-preserving procedure in older patients with minimal dysplasia of the hip with unilateral involvement. CVO should be selected for elderly patients with a CE angle greater than 5 degrees .

Acetabulum↗
PubMed2003

Identification of a novel variant in the phosphoenolpyruvate carboxykinase gene promoter in Japanese patients with type 2 diabetes.

Phospho enolpyruvate carboxykinase (PEPCK) plays an important role in gluconeogenesis and hepatic glucose production. To test the hypothesis that mutations of the PEPCK gene promoter contribute to the increased hepatic glucose production that leads to diabetes, we screened for polymorphisms of the PEPCK promoter region in 252 Japanese type 2 diabetic patients and 188 non-diabetic control subjects. A novel variant at position - 232 (C to G) was found at a similar frequency in type 2 diabetes patients (32 %) and control subjects (35 %) (p = 0.26). However, patients with the - 232 G/G genotype had an earlier age of onset than those with the - 232 C/C or - 232 C/G genotypes (p = 0.028). As the variant might well otherwise influence hormonal action, we transfected PEPCK-luciferase fusion gene constructs with the variant into human hepatoma cells and examined the response to dexamethasone, insulin, and cAMP. The reporter assay showed no significant difference in hormonal responses with the fusion gene containing the variant. Accordingly, the single-base variant at position - 232 of the PEPCK gene promoter is most probably not a major contributor to the pathogenesis of type 2 diabetes. However, this variation may be useful as a genetic marker for other metabolic disorders, especially in Japanese.

Aged↗
PubMed2001

A dot-blot-immunoassay for semen identification using a polyclonal antibody against semenogelin, a powerful seminal marker.

Among various seminal plasma proteins, semenogelin (Sg), produced in the seminal vesicle, has been considered a candidate for demonstrating the presence of semen. Sg consists of two proteins, one 52 kDa (Sg-I) in size, and the other a mixture of 71 and 76 kDa proteins (Sg-II). Recombinant Sg-I and Sg-II proteins were obtained using a baculovirus system and then injected into a rabbit to produce the respective antibodies [Characterization of recombinant precursor proteins of the human seminal plasma sperm motility inhibitor synthesized in insect cells, Int. J. Mol. Med. 2 (1998) 693]. When liquefied seminal plasma was immunoblotted with the anti-Sg-I and Sg-II antibodies, the anti-Sg-II antibody identified a wider range of the polypeptides originating from Sg than did the anti-Sg-I antibody. A dot-blot-immunoassay using anti-Sg-II antibody revealed a clear immunoreactive spot even when the semen was diluted 6400-fold. However, this assay showed that the Sg antigen was undetectable in saliva, urine, vaginal secretions, sweat, nasal secretions and serum. To determine the stability of Sg antigenic activity, filter paper with dried semen stains were kept at 37, 4 and 22 degrees C for 1, 6 and 18 months, respectively, and the Sg antigenic activity was examined. The activity was detectable in an area not less than 0.5 cm x 0.5 cm under all of the above environmental conditions during each period. Finally, semen was mixed with saliva or blood at various volumetric ratios, and used as a source of dried stains. The Sg antigenic activity was detectable in the stains until the ratio of semen to saliva or blood reached 1:8. These results suggest that Sg may be useful as a marker for semen identification.

Adult↗
PubMed2001

Percutaneous radiofrequency ablation therapy with combined angiography and computed tomography assistance for patients with hepatocellular carcinoma.

BACKGROUND: Radiofrequency ablation (RFA) for patients with hepatocellular carcinoma (HCC) has been reported previously. This technique is superior to percutaneous microwave coagulation therapy (PMCT) for the enlargement of the necrotic area. Therefore, a few treatment sessions of RFA for patients with small HCC lesions measuring < 3 cm in greatest dimension can achieve complete necrosis. To achieve this with a one-treatment RFA session, the authors designed the technique of RFA with angiography combined with computed tomography (angio-CT) assistance. The advantages of this technique are that it is possible to detect small satellite nodules and to evaluate the real-time therapeutic effect immediately after RFA. METHODS: Ten patients with 12 HCC lesions measuring < 4 cm in greatest dimension underwent RFA with angio-CT assistance. The authors performed standard RFA for six patients (seven tumors) and RFA with balloon occlusion of the hepatic artery (balloon-occluded RFA [BoRFA]) for four patients (five tumors). Final therapeutic efficacy was evaluated with dynamic CT scans performed 2 weeks after treatment. RESULTS: On CT arteriography (CTA) obtained immediately after treatment, a hyperattenuating ring around the nonenhanced region was apparent in all patients. On CT scans obtained 2 weeks after treatment, this ring disappeared, and the greatest dimension of the nonenhanced region was slightly larger than that on the CTA obtained immediately after treatment. The authors achieved complete eradication with one treatment session of RFA in 8 of 10 patients (80%). Local recurrence occurred in one patient 10 months after treatment. The greatest dimension of the area coagulated by BoRFA was significantly larger (greatest long-axis dimension, 38.2 +/- 2.8 mm; greatest short-axis dimension, 35.0 +/- 1.7 mm; n = 5 lesions) than without it (greatest long-axis dimension, 30.0 +/- 4.1 mm; greatest short-axis dimension, 27.0 +/- 4.3 mm; n = 4 lesions; greatest long-axis dimension, P = 0.009; greatest short-axis dimension, P = 0.006). No major complications occurred in any patient. CONCLUSIONS: The authors were able to achieve success with a single treatment session in patients with small HCC using RFA with angio-CT assistance. They consider that RFA with angio-CT assistance is a safe and effective technique for the treatment of patients with small HCC.

Adult↗
PubMed2001

Glucocorticoid-regulated expression of exogenous human growth hormone gene in rats.

The aim of this study was to control in vitro and in vivo expression of the growth hormone (GH) gene using a glucocorticoid-sensitive promoter, the mouse mammary tumor virus long terminal repeat (MMTV LTR). We inserted the cDNA encoding the 20-kDa form of human GH (20K-GH) downstream of the MMTV LTR of plasmid pMSG, and used lipofection to transfer it to 3Y1 cells together with plasmid pMX, which contains a puromycin-resistant element. The secretion of GH from the selected transformants was dose-dependently augmented by the application of hydrocortisone, corticosterone, or dexamethasone, among which dexamethasone was the most potent. Analysis of the time course showed that 20K-GH secretion began to increase within 2 hours after the addition of glucocorticoid and reached a maximal level of about threefold over the unstimulated control at 3 hours; secretion then gradually declined and returned to near basal levels at 19 hours. Repeated glucocorticoid application led to repeated increases in GH secretion. When GH-producing cells were microcapsulated and transplanted into the abdominal cavities of rats, 20K-GH was detected in the plasma under control conditions and increased about 3.3-fold after administration of dexamethasone. We suggest that GH expression driven by the MMTV LTR promoter may be under the control of an endogenous glucocorticoid in vivo.

Animals↗
PubMed2001

Acute epidural hematoma related to cesarean section in a neonate with Chiari II malformation.

We present a rare case of acute epidural hematoma in a newborn infant with congenital hydrocephalus that was related to Chiari II malformation. The hematoma was attributed to the application of excessive suction with a vacuum extractor during cesarean section. The clinical characteristics of neonatal epidural hematoma were analyzed after a review of 18 cases in the literature, and diagnosis and treatment are discussed with reference to the results. We propose that careful follow-up is essential in neonates with cephalohematoma, and that a computed tomography (CT) study should be performed immediately if an infant's head circumference is discovered to be enlarging or if the anterior fontanel bulges.

Arnold-Chiari Malformation↗
PubMed2001

Multiple hepatic infarction after transcatheter arterial infusion with SMANCS.

We report a patient with hepatocellular carcinoma who developed multiple hepatic infarction after transcatheter arterial infusion (TAI) with a suspension of styrene maleic acid neocarzinostatin (SMANCS) and Lipiodol (SMANCS/Lipiodol). The parameters of hepatic functional reserve were apparently decreased after the second TAI with SMANCS/Lipiodol, and the patient died of hepatic failure 103 days after the second TAI. The autopsy liver specimen revealed multiple hepatic infarctions associated with peripheral arterial stenosis or occlusion, and portal thrombosis. It is speculated that both the arterial occlusion and the portal thrombosis caused the hepatic infarction, based on a long-term insufficiency of blood supply to the hepatocytes arising from toxic arteritis caused by SMANCS/Lipiodol.

Antineoplastic Agents↗
PubMed2001

Endoscopic therapy with absolute ethanol for postoperative recurrent ulcers in intestinal Behçet's disease, and simple ulcers.

BACKGROUND: When examined macroscopically and histologically, there are no differences between "simple" intestinal ulcers and intestinal ulcers of Behçet's disease. The postoperative recurrence of intestinal Behçet's disease and simple ulcers was frequently. Medical treatment for postoperative recurrent ulcers is palliative, and the patient often requires surgery. We studied about an effect of absolute ethanol spraying via endoscopy for the ulcers. METHOD: The postoperative rate of recurrence was 56% (9/16). Commonly the ulcer recurred around the anastomotic region. We performed spraying for recurrent ulcers with absolute ethanol via endoscope in four patients. RESULTS: This therapy was effective for the recurrent ulcer in the 4 patients. In this study, the patients who were monitored and treated by the spraying of ethanol did not require further surgery. CONCLUSIONS: This therapy should performed for recurrent ulceration in cases of simple ulcer and intestinal Behçet's disease.

Administration, Topical↗
PubMed2001

Investigation of Corneal Autofluorescence in Diabetic Patients.

Purpose: The investigation of corneal autofluorescence in diabetic patients.Objects and Methods: Corneal autofluorescence was investigated with a newly-developed fluorophotometer (wave length: excitation, 290-390 nm; emission, 430-630 nm) having, fluorescence characteristics involving those of reduced pyridine nucleotides (PN) and advanced glycation endoproduct (AGE) except pentosidine and pyrraline. Twenty-eight patients with non-insulin-dependent diabetes mellitus and sixty-seven healthy volunteers were studied.Results: The corneal autofluorescence was 1.65 times higher than that of controls (P <.0001). In non-insulin-dependent diabetes mellitus, the corneal autofluorescenece was not correlated significantly with various diabetic parameters in blood (r < 0.4). In controls, the corneal autofluorescence was correlated significantly with age (r = 0.438).Conclusion: The corneal autofluorescence has some relation with PN and AGE accumulation in the cornea.

Journal Article↗
PubMed2001

Effect of prolonged marginal ascorbic acid deficiency on lenticular levels of antioxidants and lipid peroxide in guinea pigs.

We examined the effect of prolonged marginal ascorbic acid deficiency of the levels of antioxidants and lipid peroxide in lenses of guinea pigs in order to clarify lenticular antioxidant status under ascorbic acid deficiency. Male guinea pigs aged 4 weeks were given a scorbutic diet (20 g/animal per day) with either marginally deficient ascorbic acid (0.5 mg/animal per day) or sufficient ascorbic acid (1 g/animal per day) in drinking water for 3 and 6 months. The deficient group showed no lens opacity during the administration period. The deficient group had 62.3 and 53.9% of lenticular ascorbic acid content in the sufficient group at 3 and 6 months of ascorbic acid deficiency, respectively. There were no differences in lenticular contents of reduced glutathione and thiobarbituric acid reactive substances, an index of lipid peroxidation, between both groups at 3 and 6 months of ascorbic acid deficiency, while the deficient group tended to have higher lenticular vitamin E content than the sufficient group. The deficient group had higher serum vitamin E concentration than the sufficient group at 3 and 6 months of ascorbic acid deficiency. These results indicate that lenticular antioxidant status is maintained well in guinea pigs with prolonged marginal ascorbic acid deficiency, which may result in no cataract formation.

Animals↗
PubMed2001

Metabolic activation of 1alpha-hydroxyvitamin D3 in human liver microsomes.

1. 1Alpha-hydroxyvitamin D3 (1alpha-OH-D3) is a synthetic prodrug of the active form of vitamin D3, and requires the hydroxylation at the C-25 position before eliciting its biological activity. 2. 25-Hydroxylation activities for 1alpha-OH-D3 were present in both microsomal and mitochondrial fractions of human liver. 3. To determine the P450 enzyme(s) involved in microsomal 25-hydroxylation, 14 P450s (CYP1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9-Arg, 2C9-Cys, 2C19, 2D6-Val, 2D6-Met, 2E1, 3A4, 4A11) were tested for their 25-hydroxylation activity of 1alpha-OH-D3. None catalysed the 25-hydroxylation reaction. 4. 1Alpha-OH-D3 in a high concentration (2.5 ng ml(-1)) showed small but significant inhibition of the catalytic activities of CYP2C8, 2C9-Cys, 2C19, 2D6-Val and 2E1 for their typical substrates. However, 1alpha-OH-D3 in a clinically used low concentration will not significantly affect drug metabolism catalysed by the 14 P450s tested. 5. In summary, the 25-hydroxylation activity of 1alpha-OH-D3 that localizes in the microsomal fraction appears to be attributable to a cytochrome P450 other than the microsomal forms tested in this study.

Biotransformation↗
PubMed2001

Significance of serum inhibin B concentration for evaluating improvement in spermatogenesis after varicocelectomy.

BACKGROUND: The study aim was to clarify the relationship of serum inhibin B concentrations to recovery of spermatogenic function after varicocelectomy, both as a predictor of improvement in the seminogram and as a means of monitoring hormonal function after surgery. METHODS: Fifty-two varicocele patients, including five with normal sperm concentrations, were studied. Changes in the seminogram, serum hormone concentrations and serum inhibin B were evaluated in the 47 oligozoospermic patients after surgery. Preoperative inhibin B concentrations correlated significantly with serum concentrations of FSH (r = 0.598, P < 0.0001) and testosterone (r = 0.380, P < 0.02). Inhibin B concentrations also correlated significantly with sperm concentration (r = 0.351, P < 0.02) and total testicular volume (r = 0.578, P < 0.0001). No significant correlation was seen between inhibin B and the Johnsen score. Preoperative concentrations of inhibin B were higher in patients who increased their sperm concentration after surgery (responders) than in those without improved concentrations (non-responders). No significant difference was observed between pre- and postoperative inhibin B concentrations in responders or non-responders. However, 15 of 25 (60%) patients with increased inhibin B showed improvement of the seminogram, while only five of 22 (23%) patients with no change or a decrease in inhibin B had any improvement (P < 0.05). CONCLUSIONS: Preoperative serum inhibin B concentration could not reliably predict a response to varicocelectomy. However, a change in serum inhibin B concentration after varicocelectomy might be helpful to evaluate the improvement of testicular function after varicocelectomy.

Adult↗
PubMed2001

Effects of bradykinin on renal nerve stimulation-induced antidiuresis and norepinephrine overflow in anesthetized dogs.

We examined effects of bradykinin on antidiuresis and norepinephrine overflow induced by renal nerve stimulation (RNS) in anesthetized dogs, with or without blockade of the B2 receptor by Hoe 140 (D-Arg-[Hyp3, Thi5, D-Tic7, Oic8]bradykinin) or the endogenous nitric oxide generation by N(G)nitro-L-arginine (NOARG), a nitric oxide synthase inhibitor. RNS (0.5-2.0 Hz) produced significant decreases in urine flow, urinary and fractional excretions of sodium, and increases in norepinephrine secretion rate (NESR), without affecting systemic and renal hemodynamics. Intrarenal arterial infusion of bradykinin (5 ng/kg per minute) significantly suppressed the RNS-induced antidiuresis and increase in NESR. Hoe 140 (100 ng/kg per minute) did not affect the RNS-induced renal actions, but in the presence of Hoe 140, bradykinin-induced suppressive actions on reductions in urine formation and increases in NESR in response to RNS were abolished. RNS during intrarenal arterial infusion of NOARG (40 microg/kg per minute) led to potent reductions in urine formation and decreased renal blood flow and glomerular filtration rate. Simultaneously, NESR was markedly increased. During NOARG infusion, bradykinin-induced decreases in renal actions elicited by RNS were markedly attenuated. These findings suggest that bradykinin suppresses the RNS-induced norepinephrine overflow and renal actions via nitric oxide production mediated by activation of B2 receptor. Renal noradrenergic neurotransmission may be inhibited by bradykinin at the prejunctional level, when its local production in the kidney is enhanced.

Adrenergic alpha-Agonists↗
PubMed2001

[Clinical characterization of blaIMP positive gram-negative rods isolated cases].

We detected the metallo-beta-lactamase gene blaIMP positive strains of the gram-negative rods (GNR) isolated in Oita Medical University Hospital between 1993 and 1999 and studied the clinical characteristics of patients infected or colonized with blaIMP positive GNR. 25 strains (20 Pseudomonas aeruginosa and 5 Serratia marcescens) were detected and most of them were isolated from urinary samples after 1997. In the studies of antimicrobial susceptibility, some strains had sensitivity to aztreonum or imipenem although most of the strains showed multidrug resistance. When blaIMP positive GNR were isolated from patients, these strains were thought to have caused infection in 88% of the patients. About half of the patients were over 65 years old and had malignant diseases. Most of the patients had inserted urinary tract catheters, intratracheal tube or intravernous catheters. It was suggested that the insertion of the catheters were related to infection of blaIMP positive GNRs. Two patients were not treated with any antibiotics before the isolation of blaIMP positive GNRs although more than half of the patients were administered carbapenems and cephems. Most of strains were isolated in the same department and showed the same genotype by pulsed field gel electrophoresis.

Bacterial Proteins↗
PubMed2001

Pretreatment of mice with clindamycin improves survival of endotoxic shock by modulating the release of inflammatory cytokines.

Suppression of endotoxin release and subsequent production of inflammatory cytokines is crucial in the treatment of septic shock. We investigated the effect of clindamycin (CLI) on endotoxic shock induced in mice by Escherichia coli lipopolysaccharide (LPS). Mice were treated with CLI (160 to 600 mg/kg) or saline and then injected with E. coli LPS and D-(+)-galactosamine intraperitoneally 0.5 h after CLI administration. Pretreatment with CLI significantly improved survival in a dose-dependent manner (CLI, at 160, 300, and 440 mg/kg) and significantly lowered the peak concentrations of tumor necrosis factor alpha and interleukin-1beta (IL-1beta) in serum. However, the peak concentrations of IL-6 in the sera of CLI-treated mice were higher than in control mice. Our findings suggest that CLI alters LPS-induced inflammatory cytokine production and suppresses endotoxin-induced mortality in this murine model.

Animals↗
PubMed2001

Activation of histamine H3 receptors inhibits renal noradrenergic neurotransmission in anesthetized dogs.

To investigate the possible involvement of histamine H(3) receptors in renal noradrenergic neurotransmission, effects of (R)alpha-methylhistamine (R-HA), a selective H3-receptor agonist, and thioperamide (Thiop), a selective H3-receptor antagonist, on renal nerve stimulation (RNS)-induced changes in renal function and norepinephrine (NE) overflow in anesthetized dogs were examined. RNS (0.5-2.0 Hz) produced significant decreases in urine flow and urinary sodium excretion and increases in NE overflow rate (NEOR), without affecting renal hemodynamics. When R-HA (1 microg x kg(-1) x min(-1)) was infused intravenously, mean arterial pressure and heart rate were significantly decreased, and there was a tendency to reduce basal values of urine flow and urinary sodium excretion. During R-HA infusion, RNS-induced antidiuretic action and increases in NEOR were markedly attenuated. Thiop infusion (5 microg x kg(-1) x min(-1)) did not affect basal hemodynamic and excretory parameters. Thiop infusion caused RNS-induced antidiuretic action and increases in NEOR similar to the basal condition. When R-HA was administered concomitantly with Thiop infusion, R-HA failed to attenuate the RNS-induced antidiuretic action and increases in NEOR. However, in the presence of pyrilamine (a selective H1-receptor antagonist) or cimetidine (a selective H2-receptor antagonist) infusion, R-HA attenuated the RNS-induced actions, similarly to the case without these antagonists. Thus functional histamine H3 receptors, possibly located on renal noradrenergic nerve endings, may play the role of inhibitory modulators of renal noradrenergic neurotransmission.

Animals↗