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Biomedical subjects

M Yokoyama

Publications and source records attributed to M Yokoyama.

At least 37 records · Page 2Linked to original sources
PubMed2003

Fine needle aspiration cytology for soft tissue tumours of the hand.

The purpose of this study was to evaluate the usefulness of fine needle aspiration cytology for the preoperative diagnosis of soft tissue tumours of the hand. Fine needle aspiration cytology was performed on 93 soft tissue tumours of the hand which were classified as malignant, benign or unclassified based on cytological findings. We also attempted to make specific diagnosis by cytology. The cytological diagnosis was then compared with the postoperative histopathological diagnosis. The cytological differentiation between benign and malignant tumours showed neither false-positive nor false-negative results. Of the 47 lesions with sufficient material for cytology and that were postoperatively diagnosed histologically, 35 (including one recurrent lesion) were correctly diagnosed by fine needle aspiration cytology. No complications were encountered. Fine needle aspiration cytology has a high degree of diagnostic accuracy and safety for soft tissue tumours of the hand.

Adolescent↗
PubMed2003

Normalization of low biotinidase activity in a child with biotin deficiency after biotin supplementation.

We report findings in a Japanese boy with severe skin rash attributable to biotin deficiency. The patient had an intracranial malformation and developed biotin deficiency due to tube feeding with a single formula for over one year. Results of urinary organic acid analysis were consistent with multiple carboxylase deficiency, and low biotinidase activity was also observed. After biotin supplementation, the skin rash improved and biotinidase activity normalized. We speculate that biotin is one regulating factor in the biosynthesis of biotinidase.

Biotin↗
PubMed2003

Helicobacter pylori and Campylobacter rectus share a common antigen.

AIM: The aim of this study was to investigate the presence of antigens with immunological cross-reactivity in periodontopathogenic bacteria and Helicobacter pylori, the pathogen associated with gastritis and peptic ulcers in human. MATERIALS AND METHODS/RESULTS: Among the putative periodontopathogens tested (Actinobacillus actinomycetemcomitans, Campylobacter rectus, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola), cross-reactive bands were only detected in C. rectus by SDS-PAGE/Western immunoblotting analysis using a polyclonal antibody directed to H. pylori cells. One of these cross-reactive antigens, a 64-kDa band antigen, also reacted with a monoclonal antibody directed to the human heat shock protein (HSP) 60. The N-terminal amino acid sequence of this C. rectus protein revealed a high degree of homology with corresponding regions of other HSPs belonging to the HSP60 family, indicating that the 64-kDa antigen was a GroEL protein. The nucleotide sequence of the C. rectus GroEL protein coded for a 547 amino acid protein with a predicted size of 57.8 kDa. Comparison of the alignment of the deduced amino acid sequence of the GroEL protein of C. rectus with that of H. pylori showed a high degree of similarity throughout its length (76.8%). GroEL protein from C. rectus possessed the ability to stimulate production of IL-6 by a confluent monolayer of human gingival epithelial cells and was cytotoxic when used at a high concentration. CONCLUSIONS: This study reveals an immunological relationship between H. pylori and C. rectus, and clearly indicates that one of the shared antigens is a GroEL protein possessing a biological activity that might play a role in the initiation and progression of periodontal disease.

Antibodies, Monoclonal↗
PubMed2003

Lack of association of the interleukin-1 receptor antagonist gene with palmoplantar pustulosis in Japanese.

We analysed a polymorphism of the interleukin (IL)-1 receptor antagonist (IL1RN) gene in 93 Japanese patients with palmoplantar pustulosis (PPP). None of the IL1RN alleles was significantly increased in the patients compared with controls. Because PPP has been reported to be associated with the tumour necrosis factor (TNF) region, we examined the association between the TNF and IL1RN genes. There was a difference in IL1RN*2 positivity between patients with and without the AA genotype of the TNF gene. In contrast, such a difference was not found in controls. These data indicate a possible epistatic effect between TNF and IL1RN linked genes for susceptibility to the pathogenesis of PPP.

Adult↗
PubMed2003

A prospective and randomized study of primary hormonal therapy for patients with localized or locally advanced prostate cancer unsuitable for radical prostatectomy: results of the 5-year follow-up.

OBJECTIVE: To evaluate the effect of primary hormonal therapy for patients with localized and locally advanced prostate cancer. PATIENTS AND METHODS: Patients with stage T1b-T3 prostate cancer who were not scheduled for radical prostatectomy were allocated into two groups: group 1 (73 men) received luteinizing hormone-releasing hormone (LHRH) agonist monotherapy and group 2 (78 men) received LHRH agonist and chlormadinone acetate. Patients were followed using serum prostate specific antigen levels, prostate size and the detection of distant metastasis for 5 years. RESULTS: The median (range) follow-up was 78 (63-87) months. The 5-year progression-free survival rate was significantly higher in group 2 (68%) than in group 1 (47%). However, the overall and cause-specific survival rate at 5 years were similar in both groups, at 72% and 93% in group 1, and 64% and 89% in group 2, respectively. CONCLUSION: The overall survival rates of the both groups were no different from that of the normal Japanese population of the same age group. Although this study did not include an untreated group, i.e. watchful waiting, these results might indicate the usefulness of primary hormonal therapy in controlling localized and locally advanced prostate cancer. The 5-year observation period is still short and the study is continuing to determine the 10-year survival.

Aged↗
PubMed2003

A new method using a bacterium for dissolution of urinary stones.

PURPOSE: A bacterium, Thiobacillus thiooxidans, oxidizes inorganic sulfur compounds to sulfuric acid to obtain energy for growth. We examined dissolution of urinary stones by the bacteria and studied optimal conditions for the dissolution in human urine. METHODS: Thiobacillus thiooxidans (IFO No. 13 701) was purchased from Hakko Kenkyujyo, Co., Osaka, Japan. The bacteria were grown stationary for 7 days at 30 degrees C in medium. The pH of the medium was changed from pH 4.82 to 1.95 for 28 days. Growth of the bacteria was also examined in human urine by addition of different amounts of sodium thiosulfite. The dissolution of human urinary stones was examined in the bladder of Wistar rat containing the bacteria (1 x 10(8)) for 7 days. 20 ml of 5 % sodium thiosulfite were injected intraperitoneally once a day. Histological changes of urinary tracts and blood test were also examined. As a control, two rats were examined in the same methods without the bacteria. RESULTS: The number of bacteria was increased in human urine depending on the concentration of sodium thiosulfite. Among different kinds of urinary stones, calcium phosphate stone was most dissolved, 78 % reduction of dry weight in the rat bladder. Calcium oxalate, uric acid and magnesium phosphate stones were not well dissolved. But the stone weights in the control rats were increased twice. Slight inflammation was found in the rat bladder. There were no abnormal findings in the blood test. CONCLUSIONS: Thiobacillus thiooxidans can be used for dissolution of urinary stones. This new technique may be useful for dissolution of fragments after ESWL and crystals covered by a urinary stent. Optimal conditions and safety methods should be developed for clinical use.

Acidithiobacillus thiooxidans↗
PubMed2003

Nitrogen balance and ileal amino acid digestibility in growing pigs fed diets reduced in protein concentration.

Two studies were conducted to assess the effect of dietary protein reduction on N utilization, N excretion, and AA digestibility in growing pigs. The objective was to determine whether pigs fed diets with a reduced CP concentration could maintain the same N retention as pigs fed an adequate diet. The second objective was to test whether reducing dietary CP concentration decreases AA digestibility. In each study, six barrows were allotted to one of six dietary treatments in a Latin square design. Treatments consisted of four corn-soybean meal-based diets containing 15, 12, 9, and 6% CP, a casein-based diet containing 15% CP, and a protein-free diet. Crystalline AA were included in the 12, 9, and 6% CP diets. The indispensable:dispensable AA ratio was maintained at 45:55 with the addition of L-glutamic acid to the 9 and 6% CP diets. The casein-based and protein-free diets were used to determine endogenous total tract N and ileal AA losses. In the first study, total N losses and N absorbed decreased linearly (P < 0.001) as dietary CP concentration decreased from 15 to 6%. Both a linear (P < 0.001) and a quadratic (P < 0.05) decrease in N retention were found with decreasing dietary CP concentration. Nitrogen retained as a percentage of intake and absorbed increased (P < 0.001) as dietary CP concentration was reduced from 15 to 6%. In the second study, six barrows were surgically fitted with a T-cannula at the terminal ileum to determine ileal AA digestibility. For all dispensable and most indispensable AA, apparent and standardized ileal digestibility increased linearly (P 0.01, and for arginine, P < 0.05) as dietary CP concentration decreased. These results indicate that dietary CP concentration can be decreased from 15 to 12% with crystalline AA supplementation to meet an ideal AA profile without adversely affecting N retention, and that decreasing dietary CP concentration from 15 to 6% increases both dispensable and indispensable AA ileal digestibility.

Amino Acids↗
PubMed2003

Ammonia, volatile fatty acids, phenolics, and odor offensiveness in manure from growing pigs fed diets reduced in protein concentration.

The objective of this study was to investigate whether reducing dietary CP concentration decreases fecal VFA, manure ammonia (NH3) emission and odor, and urinary phenolic metabolites. Six barrows were allotted to one of six dietary treatments in a Latin square design. Treatments consisted of four corn-soybean meal based diets containing 15, 12, 9, and 6% CP, a casein-based diet containing 15% CP, and a protein-free diet (0% protein). Crystalline AA were included in the 12, 9, and 6% CP diets. The casein-based and protein-free diets were used to determine basal endogenous contribution of VFA, phenolics, NH3, and manure odor. Pigs were housed individually in metabolism cages to allow total collection of feces and urine. Feces and urine were collected and pooled within pig and period. Feces and urine were analyzed for VFA and phenolic metabolite concentrations, respectively. Feces and urine were then mixed, stored, and fermented at room temperature for 30 d. For NH3 determination, headspace air was sampled from manure slurries at 24, 48, and 72 h after fermentation. Slurry samples were placed into vials, capped, and randomized before odor panel evaluation. Odor offensiveness was classified on severity: 1 = non-offensive; 2 = mildly offensive; 3 = moderately offensive; 4 = strongly offensive; and 5 = extremely offensive. Reducing dietary CP increased (P < 0.05) fecal VFA concentrations but did not affect phenolic concentrations in urine. Manure NH3 emission was reduced (P < 0.05) as dietary CP concentration decreased from 15 to 0%. The 15% diet had the least offensive manure slurry with odor qualitative ranking of 2.58 (i.e., mild-moderately offensive). Compared with the 15% CP diet, manure from the 9 and 6% CP diets was found to be more offensive (P < 0.05), with qualitative rankings of 2.92 and 3.10, respectively. Odor qualitative rank for the 12% CP, protein-free diet, and casein-based diet did not differ from that of the 15% CP diet. These results indicate that reduction in dietary CP concentrations decreases manure NH3 emission, but it does not diminish manure odor offensiveness and fecal VFA concentrations.

Ammonia↗
PubMed2002

Island dynamics in the large-helical-device plasmas.

In the Large Helical Device plasma discharges, the size of an externally imposed island with mode number ( n/m = 1/1) decreases substantially when the plasma is collisionless ( nu(*)< approximately 1) and the beta is finite ( > approximately 0.1%) at the island location. For the collisional plasmas with finite beta, on the other hand, the size of the island increases. However, there is a threshold in terms of the vacuum island size below which the island enlargement is not seen.

Journal Article↗
PubMed2002

Antigenic properties of the GroEL-like protein of Campylobacter rectus.

The purpose of this study was to clarify the antigenic properties of the GroEL-like protein of Campylobacter rectus using a specific polyclonal antibody directed to the purified 64-kDa GroEL-like protein (pAb-CrGroEL), a polyclonal antibody directed to the Actinobacillus actinomycetemcomitans GroEL-like protein (pAb-AaGroEL) and a monoclonal antibody against the recombinant human HSP60 (mAb-HuHSP60). In SDS-PAGE/Western immunoblotting analysis, mAb-HuHSP60, pAb-CrGroEL and pAb-AaGroEL were found to react with the GroEL-like protein (64-kDa) present in all C. rectus strains. A 150-kDa protein in C. rectus ATCC 33238 also reacted strongly with pAb-CrGroEL. This 150-kDa protein was found to be present on the surface-associated material of bacterial cells, as determined by transmission electron microscopy and immunogold labelling of cells with pAb-CrGroEL. Analysis of the first 20 N-terminal amino acids of the sequence of the 150-kDa protein revealed a strong homology (80%) with the C. rectus surface layer (S-layer) protein. Investigation of the biochemical nature of antigenic determinants using periodic acid and proteolytic enzymes showed that the C. rectus GroEL-like protein possessed immunodominant epitopes in both peptide and carbohydrate chains, and that the immunoreactive determinants of the 150-kDa protein belonged to carbohydrate. These results suggest that the GroEL-like protein and the S-layer protein of C. rectus may share the same carbohydrate epitopes.

Aggregatibacter actinomycetemcomitans↗
PubMed2002

Diffuse proliferative glomerulonephritis after bone marrow transplantation.

A 15-year-old boy developed nephrotic syndrome and acute renal failure 4 years after allogenic bone marrow transplantation (BMT) for lymphoid crisis of chronic myelocytic leukemia. On admission, he presented with clinical features of chronic GVHD including transient exacerbation of cholestatic liver injury. Renal biopsy showed diffuse proliferative glomerulonephritis with cellular crescents. The patient was treated with methylprednisolone pulse therapy (1 g/day, for 3 days) followed by oral prednisolone. Renal function gradually improved but nephrotic state was persistent. A second renal biopsy showed improvement of acute tubular necrosis and endocapillary proliferation and transformation of crescents into a fibrous form. After tapering of oral prednisolone, cyclophosphamide was started, which resulted in a gradual improvement of proteinuria. Several cases of nephrotic syndrome occurring after BMT have already been reported, but most cases had membranous nephropathy. In our case, renal biopsy revealed diffuse proliferative glomerulonephritis with findings of active cellular immunity, and aggressive treatment resulted in attenuation of these findings. Moreover, chronic GVHD-related liver injury was noted at the time of this episode. Our findings suggest that chronic GVHD may be complicated with diffuse proliferative glomerulonephritis through unknown cellular immune mechanism.

Adolescent↗
PubMed2002

[Total aortic arch replacement for distal aortic arch aneurysm with adhered left lung: report of a case].

A 76-year-old man with a history of pleuritis and a cerebral infarct underwent a total arch replacement for an aneurysm of the distal aortic arch. Computed tomography revealed a true aneurysm having a maximum diameter of 70 mm as well as pleural thickening and calcification. Total arch replacement with selective cerebral perfusion was performed through median sternotomy and left thoracotomy. The myocardial ischemic time was shortened by reperfusion from the right axillary artery after the anastomosis of the proximal ascending aorta and the brachiocephalic artery. After the other branches of the arch were anastomosed, a distal anastomosis through the left thoracotomy was then performed using the pull-through method, enabling minimal decortication of the adhered lung. Our surgical procedure for distal arch aneurysm with adhered lung involves the addition of a left thoracotomy, but the reduction in the myocardial ischemic time and lung injury are of benefit.

Aged↗
PubMed2001

Usefulness of beat-to-beat QT dispersion fluctuation for identifying patients with coronary heart disease at risk for ventricular arrhythmias.

QT dispersion (QTd) has been proposed as a marker of ventricular repolarization inhomogeneity and arrhythmic risk, but despite the dynamic properties of ventricular repolarization and the fact that QTd represents only a static parameter of the repolarization event, beat-to-beat QTd behavior has not been assessed so far. Beat-to-beat QTd was automatically measured in 12-lead digitized electrocardiographic recordings obtained over 10 minutes from 77 subjects. Forty-seven patients had coronary heart disease without a history of ventricular arrhythmias, 12 had coronary heart disease and documented ventricular tachycardia, and 18 were normal subjects. Mean QTd, the difference between the maximum minus the minimum QTd observed over the recording time (QTd variation), the maximum difference of QTd between consecutive beats (QTd maximum), and QTd SD (QTd variability) were analyzed between groups. The temporal QTd parameters were significantly increased in the group of patients with susceptibility to ventricular arrhythmias compared with those in both healthy subjects (QTd variation p <0.0001, QTd maximum p <0.001, QTd variability p <0.0001) and patients without a history of ventricular tachycardia (QTd variation p <0.01, QTd maximum p <0.01, QTd variability p <0.01). Mean QTd was also significantly increased in the groups of patients with and without ventricular tachycardia compared with controls (p <0.001 and <0.01), but did not differ significantly between the 2 patient groups. Thus, QTd has a dynamic behavior with significant beat-to-beat fluctuations even in normal subjects and is more marked in patients with coronary heart disease at risk for ventricular arrhythmias.

Aged↗
PubMed2001

Angiotensin II induces circadian gene expression of clock genes in cultured vascular smooth muscle cells.

BACKGROUND: Daily rhythms of mammalian physiology and endocrinology are regulated by circadian pacemakers. The master circadian pacemaker resides in the suprachiasmatic nucleus, which is located in the hypothalamus of the brain, but circadian oscillators also exist in peripheral tissues. Because many studies have demonstrated apparent circadian variations in the frequency of cardiovascular disorders, it is of great interest to investigate a possible relation between circadian gene expression and cardiovascular function. We examined whether a circadian oscillation system exists in the aorta and/or in cultured vascular smooth muscle cells (VSMCs). METHODS AND RESULTS: The mRNA levels of clock genes were assayed by northern blot analysis. The mouse aorta showed a clear circadian oscillation in the expression of mPer2, dbp, and Bmal1. Brief treatment of VSMCs with angiotensin II induced a robust increase in mPer2 gene expression, followed by a marked reduction in mPer2 mRNA levels and subsequent synchronous cycling of mPer2, dbp, and Bmal1 mRNAs. The induction of mPer2 in VSMCs by angiotensin II was completely abolished by treatment with CV11947, a specific angiotensin II type1 receptor antagonist. CONCLUSIONS: The present results demonstrate that the aorta and VSMCs possess a circadian oscillation system which is comparable to that of the suprachiasmatic nucleus and that the circadian gene expression in VSMCs is induced by angiotensin II through the angiotensin II type1 receptor. Our in vitro system will provide a useful tool to further analyze the physiological significance of the peripheral clock in cardiovascular function.

ARNTL Transcription Factors↗
PubMed2001

Liver metastases are less established after gasless laparoscopy than after carbon dioxide pneumoperitoneum and laparotomy in a mouse model.

BACKGROUND: Although the liver is the most frequent site of cancer recurrence after conventional open surgery for colorectal cancer, the effect of laparoscopic procedures with or without gas insufflation on the development of liver metastases is largely unknown. METHODS: Male BALB/C mice inoculated intraportally with colon 26 cells were randomized to undergo carbon dioxide pneumoperitoneum (n = 14), abdominal wall lifting (n = 14), or full laparotomy (n = 12), or to serve as control subjects without any procedures other than tumor inoculation (n = 13). RESULTS: The growth of liver metastases 14 days after surgery was enhanced after full laparotomy (p < 0.01) and pneumoperitoneum (p = 0.02), as compared with that in the control subjects, whereas there was no difference in the growth of liver metastases between abdominal wall lifting and the control condition (p = 0.99). CONCLUSIONS: These results suggest that the defense against liver metastasis is better preserved after the gasless procedure than after laparotomy and carbon dioxide pneumoperitoneum in the reported animal model.

Animals↗
PubMed2001

Taurine prevents the decrease in expression and secretion of extracellular superoxide dismutase induced by homocysteine: amelioration of homocysteine-induced endoplasmic reticulum stress by taurine.

BACKGROUND: Hyperhomocysteinemia is an independent risk factor for atherosclerosis. Homocysteine has been shown to induce endoplasmic reticulum (ER) stress in vascular endothelial cells. ER stress is a condition in which glycoprotein trafficking is disrupted and unfolded proteins accumulate in the ER. ER molecular chaperons, such as GRP78, are induced and an ER resident kinase, PERK, is activated when cells are subjected to ER stress. Conversely, taurine is reported to have antiatherogenic effects by unknown mechanisms. To elucidate the mechanisms by which homocysteine induces atherosclerosis and taurine prevents it, we examined whether homocysteine and taurine affect the expression and secretion of extracellular superoxide dismutase (EC-SOD), a glycoprotein secreted from vascular smooth muscle cells (VSMCs) that protects the vascular wall from oxidative stress. METHODS AND RESULTS: We assessed the expression of EC-SOD and GRP78 mRNA in cultured rat VSMCs by Northern blot analysis. The EC-SOD protein secreted into the culture medium was examined by Western blot analysis. Homocysteine (5 mmol/L) and other ER stress inducers, including A23187, were found to decrease EC-SOD mRNA expression and protein secretion. Furthermore, they upregulated GRP78 mRNA expression and activated PERK. Taurine (0.5 to 10 mmol/L), conversely, prevented these actions induced by homocysteine. CONCLUSIONS: Homocysteine induces ER stress and reduces the secretion and expression of EC-SOD in VSMCs, leading to increased oxidative stress in the vascular wall. Taurine restores the secretion and expression of EC-SOD by ameliorating ER stress induced by homocysteine.

Animals↗
PubMed2001

Involvement of NADH/NADPH oxidase in human platelet ROS production.

Platelets play an important role in atherosclerotic and thromboembolic vascular diseases. It has been reported that reactive oxygen species (ROS) could modify platelet function, and platelets themselves have the ability to produce ROS. However, the enzymatic sources of ROS in platelets have not been fully determined. The NADH/NADPH oxidase system was originally identified as the major source of ROS in phagocytes. Recently, it has become evident that this oxidase is functionally expressed not only in phagocytes but also in various cell types. The present study was undertaken to test the hypothesis that NADH/NADPH oxidase might be expressed in human platelets. Lucigenin-enhanced chemiluminescence (L-CL) and electron spin resonance (ESR) method demonstrated that human platelets obtained from healthy volunteers released ROS, and the released ROS were increased by stimulation with 12-O-tetradecanoylphorbol-13-acetate (TPA) or calcium ionophore. Homogenates of human platelets, as well as MEG01 cells, megakaryocytic cell line, had the enzymatic activity to produce superoxide in NADH/NADPH-dependent manners. This enzymatic activity was suppressed by diphenylene iodonium (DPI), an inhibitor of NADH/NADPH oxidase. Western blot analysis demonstrated that platelets and MEG01 cells expressed p22(phox) and p67(phox) proteins, components of NADH/NADPH oxidase. Thus, human platelets have the enzymatic activity of p22(phox)-based NADH/NADPH oxidase, and this oxidase is likely one of the important sources of ROS in platelets.

Blood Platelets↗