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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 451 records · Page 25Linked to original sources
PubMed1995

Role of basic and acidic fragments in delicious peptides (Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala) and the taste behavior of sodium and potassium salts in acidic oligopeptides.

The role of the acidic fragment (Asp-Glu-Glu) in delicious peptides was investigated in detail by using the Na+ or K+ salts of acidic oligopeptides so that amount of Na+ or K+ intake of peptides composed of acidic amino acids could be varied by changing their sequences. The taste of these peptides was confirmed to vary with Na+ or K+ intake. Additionally, in order to study the role of basic (Lys-Gly) and acidic (Asp-Glu-Glu) fragments in delicious peptides for producing the taste, five delicious peptide analogs, Ser-Leu-Ala-Lys-Gly-Asp-Glu-Glu, Ser-Leu-Ala-Asp-Glu-Glu-Lys-Gly, Lys-Gly-Ser-Leu-Ala-Asp-Glu-Glu, Lys-Gly-Asp-Glu-Glu, and Glu-Glu-Asp-Gly-Lys, were synthesized. The intensity of the umami and/or salty taste of these peptides and their Na salts was almost the same, despite their chemical structures being different. These results indicate that the acidic fragment as well as the basic fragment plays an important role in the taste production and intensity of delicious peptides, and that an umami or salty taste can be produced by the localization of the cation of the basic fragment and the anion of the acidic fragment.

Amino Acid Sequence↗
PubMed1995

Polysplenia syndrome with common atrioventricular canal and persistent truncus arteriosus.

A case of an infant with a rare combination of polysplenia syndrome with common atrioventricular canal and persistent truncus arteriosus is presented. In our present case, severe common atrioventricular valve regurgitation was identified, as in previous cases. To our knowledge, echocardiographic and autopsy findings of this association has not been previously reported. The persistent truncus arteriosus is extremely rare in the setting of the polysplenia syndrome, but the present case report demonstrates that these anomalies may, at times, occur.

Abnormalities, Multiple↗
PubMed1995

Improvement of hypothyroidism after glucocorticoid replacement in isolated adrenocorticotropin deficiency.

We report a 50-year-old female who suffered from reversible hypothyroidism accompanied by isolated ACTH deficiency. There were no findings indicating a complication of autoimmune thyroiditis. Replacement of maintenance dose of glucocorticoid not only led to improvement of thyroid function, but also caused a transient decrease in T3 and an increase in reverse T3, suggesting that chronic cortisol deficiency may impair thyroid function, and that the maintenance dose, as well as pharmacological doses of glucocorticoids may influence T4 deiodination. The findings of this case suggest that thyroid function should be re-evaluated to avoid unnecessary replacement of thyroid hormone, a few months after glucocorticoid replacement.

Adrenocorticotropic Hormone↗
PubMed1995

A dialysis patient with systemic calciphylaxis exhibiting rapidly progressive visceral ischemia and acral gangrene.

Systemic calciphylaxis is a rare, poorly understood syndrome of progressive peripheral ischemic necrosis and medial arterial calcification in patients with end-stage renal disease. We report a patient with this syndrome which developed following corticosteroid administration and who ultimately required amputation of the four extremities. Furthermore, cerebral, myocardial, splenic, and intestinal infarctions also developed in parallel with the increment of visceral arterial calcification. No evidence of noticeable hyperparathyroidism or elevation of serum calcium-phosphate product was observed. We speculated that, in addition to diabetes mellitus and chronic renal failure while undergoing dialysis therapy, the administration of corticosteroids might act synergistically to cause calciphylaxis.

Calciphylaxis↗
PubMed1995

Diagnosis and treatment of brainstem abscess using magnetic resonance imaging and microsurgical aspiration--case report.

A 6-year-old boy presented with a pontine abscess initially misdiagnosed as brainstem glioma, but he deteriorated rapidly and developed new symptoms of respiratory distress. Magnetic resonance (MR) imaging revealed a rapidly growing mass lesion in the pons. Microsurgical evacuation of the abscess via a suboccipital retromastoid approach resulted in neurological improvement and resolution of the lesion on MR images. Brainstem abscess can be successfully treated with early, accurate diagnosis based on MR imaging and appropriate microsurgical and antibiotic management.

Brain Abscess↗
PubMed1995

alpha-Difluoromethylornithine increases the anti-tumor effect of cis-diamminedichloroplatinum in G-XII rat glioma.

The in vivo effects of the single or combined administration of alpha-difluoromethylornithine (DFMO), an inhibitor of polyamine synthesis, and cis-diamminedichloroplatinum (cisplatin) on the growth of G-XII glioma cells inoculated subcutaneously in rats were tested. Treatment with DFMO or cisplatin significantly decreased the bromodeoxyuridine (BrdU) labeling index of tumor tissues. Combined treatment with DFMO and cisplatin achieved a further significant decrease in the BrdU labeling index. All treatments significantly reduced the tissue levels of N1-acetylspermidine and putrescine, and the ornithine decarboxylase (ODC) activity, but little affected the tissue levels of spermidine and spermine, and the activity of spermidine/spermine N1-acetyltransferase. The reduction of ODC activity by cisplatin treatment may be associated with the anti-tumor effect.

Acetyltransferases↗
PubMed1995

Adsorption of saliva-coated and just-harvested Streptococcus sanguis to saliva-coated hydroxyapatite beads.

It is possible that salivary proteins on bacterial cells have some influence on the adsorption of oral bacteria to the surface of oral tissues. The aim of this study was to clarify the influence of salivary proteins attached to the surface of Streptococcus sanguis ATCC 10556 (S. sanguis) on bacterial adsorption to hydroxyapatite beads treated with salivary proteins (S-HA beads). Just-harvested cells (N-system) and saliva-coated cells (C-system) were used. The results showed that adsorption to S-HA beads was gradually reduced by a covering of salivary proteins. No influence was observed on the adsorption of cells due to the presence of divalent cations, phosphate or EDTA when the N-system and C-system were compared. Though it was evident that hydrophobic bonding was involved in adsorption in the N-system, few such effects were observed in the C-system. Adsorption was inhibited to varying degrees by sugars in both systems. Pretreatment of cells with heat affected adsorption differently in the N-system and C-system. These findings suggest that salivary proteins attached to the bacterial cell surface may influence its adsorption to oral tissues.

Adsorption↗
PubMed1995

Bacterial adsorption to fetuin and mucin pellicle.

The ability of Actinomyces viscosus (A. viscosus) WVU 627 to attach to hydroxyapatite (HA) beads treated with either bovine fetuin or bovine mucin was studied. All preparations used were blocked with bovine serum albumin prior to incubation with [3H] thymidine-labeled A.viscosus cells. The quantity of fetuin or mucin adsorbed on the HA beads was determined by use of [3H] fetuin or [3H] mucin. Approximately 6 micrograms protein of [3H] fetuin and 20 micrograms of protein of [3H] mucin adsorbed to 5 mg of HA beads at saturation, respectively. The presence of fetuin or mucin on HA beads promoted attachment of the organism. However, HA beads treated with human whole saliva as a positive control promoted A.viscosus attachment more effectively than HA beads treated with these glycoproteins. Attachment of two additional strains (B 236 and B 25) of A. viscosus to HA beads was also promoted by these glycoproteins. The number of A.viscosus cells which attached to fetuin-treated HA beads was dose-dependent, except for strain B 25. For all three A.viscosus strains tested, attachment to the experimental pellicle with mucin was dose-dependent. These findings suggest that the use of these newly developed bacterial adhesion assay systems may be effective for elucidating bacterial adhesion mechanisms.

Actinomyces↗
PubMed1995

Effect of docosahexaenoic acid and sardine oil diets on the ultrastructure of hepatocytes in adult mice.

The influence of docosahexaenoic acid (DHA) on the ultrastructure of hepatocytes was studied. Adult male mice of Crj:CD-1 (ICR) strain were fed a fat-free purified diet supplemented with 5% (by weight) of purified DHA, refined sardine oil, and palm oil. The mice were fed the DHA diet or the palm oil diet for 7 days, and the sardine oil diet or the palm oil diet for one month. There were significant ultrastructural changes in the hepatocytes between the mice fed palm oil diet and the animals fed DHA and sardine oil diets. Many lipid droplets in the tissues of mice fed the palm oil diet were observed. Few lipid droplets were contained in the hepatocytes from the mice fed DHA and sardine oil diets, but electron-dense bodies were found in their tissues. These electron-dense bodies were mainly found near the region of the nucleus, blood sinusoids and bile canaliculi. These results suggest that the dense bodies found in the DHA and sardine oil diet groups may appear as a result of acceleration of lipid metabolism in the liver of mice.

Animals↗
PubMed1995

[Evaluation of cavernous artery by color Doppler ultrasonography--significance of ultrasonic beam angle].

Penile Doppler ultrasonography is widely accepted as an essential examination in the diagnosis of impotence. However, measurement blood flow velocity using Doppler ultrasonography may be subject to some errors. We performed color Doppler ultrasonography in 63 patients with normal penile vascular function as diagnosed using positive responses to intracavernous pharmacological stimulation. We compared the Doppler measurement results of the 126 cavernous arteries and the ultrasonic beam angles. We used a Hitachi EUB 515, a sonographic probe of 7.5 MHz, a sampling width of 0.8 mm, a sampling depth of 1 mm, and a wall motion filter was not used. Ultrasonic beam angles were 5 to 77 degrees. The mean peak systolic velocity and end diastolic velocity values were 40. 0 cm/s and 3.9 cm/sec, respectively. The peak systolic velocity and end diastolic velocity values remained stable regardless of the ultrasonic beam angles (Kruskal-Wallis test, p = 0.56, p = 0.70). However, the variance of values became greater when the ultrasonic beam angles was larger than 55 degrees in the case of peak systolic velocity (F test, p < 0.05) and 50 degrees in the case of end diastolic velocity (F test, p < 0.05), indicating a reduction in reliability. Resistance index variance was significantly higher when ultrasonic beam angle exceeds 50 degrees (F test, p < 0.05). We believe that we should accept only those cavernous artery peak systolic velocity measurements as reliable when the ultrasound beam angle is less than 55 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Clinical study on measurement of cerebral metabolism and oxygenation during cardio-pulmonary bypass by near-infrared spectrophotometry].

We studied the non-invasive method of monitoring of cerebral metabolism and oxygenation of patients mainly with thoracic aortic aneurysm during Cardio-pulmonary bypass (CPB) by Near-infrared Spectrophotometry (NIRS) to establish the safety limits of cerebral perfusion. NIRS monitoring of all 12 patients showed that cerebral oxygenation levels were maintained within the pre-CPB range when mean arterial perfusion pressure (MAPP) was above 60 mmHg. With considering rectal temperature, the cerebral oxygenation levels were maintained above the pre-perfusion baseline when MAPP was above 50 mmHg at rectal temp. < or = 25 degrees C, and 73 mmHg at > or = 25 degrees C. It was suspected that cerebral autoregulatory mechanism could exist even in hypothermia (< or = 25 degrees C) because cerebral oxy-Hb and blood volume was significantly declined when MAPP was reduced to 40 mmHg or less. In 5 patients who underwent selective cerebral perfusion, the base line level of blood volume was preserved when the perfusion flow rates were above 0.5l/min, and the desirable oxy-Hb levels were obtained when the flow rates were above 0.4l/min. During deep hypothermic circulatory arrest (18 degrees C), cerebral oxy-Hb level was gradually reduced from baseline, reflecting proceeding metabolic activity even in profound hypothermia. These findings led us to conclude that non-invasive, continuous, and direct monitoring of cerebral oxygenation using NIRS can provide valuable data to prevent cerebral injury after CPB. It is hoped that the safety limits of cerebral perfusion and circulatory arrest can be established in the future using multiple analysis of pressure, flow, temperature, Hb concentration and so far by NIRS.

Aged↗
PubMed1995

[Diagnostic value of tissue polypeptide antigen in pleural effusions with malignant pleural mesothelioma].

There are no known tumor makers of malignant pleural mesothelioma. We measured the concentration of TPA in the pleural effusions from patients with malignant pleural mesothelioma and from patients with other pleural diseases, evaluate its clinical usefulness. The concentration of TPA was more than 7,000 U/l (mean: 18,600 +/- 9,867 U/l, n = 5) in all patients with malignant pleural mesothelioma, but it was less than 4,000 U/l in those with benign asbestos pleurisy and other benign pleural effusion (benign asbestos pleurisy 1,598 +/- 570, n = 5: p < 0.01, tuberculous pleurisy 1.37 +/- 759, n = 11: p < 0.01, others 2,497 +/- 2,152 n = 3: p < 0.05). The concentration of TPA in the pleural effusions was not significantly different between malignant pleural mesothelioma and lung cancer (12,287 +/- 17,070 U/l). However, in all patients with lung cancer and high TPA concentrations, cytologically malignant cells were detected in the pleural effusions. TPA was high in all five patients with malignant pleural mesothelioma, but cytologically malignant cells were detected in only one patient. Only in malignant pleural mesothelioma (not in other benign disease or in lung cancer) was the concentration of TPA more than 4,000 U/l, and no evidence of malignancy was obtained by cytological methods. These findings suggest that assessing TPA in the pleural effusion might contribute to the diagnosis of malignant pleural mesothelioma.

Adult↗
PubMed1995

[A case of sarcoidosis with advanced cystic and fibrotic changes in a young patient].

A 29-year-old man was referred to our hospital because of exertional dyspnea and progressive eruption on the buttocks and the lower extremities. Chest roentgenograms and computed tomograms taken at that time revealed diffuse fibrotic changes accompanied by multiple cavities and bullae in the lungs. There were no signs of mediastinal or hilar lymphadenopathy. A chest roentgenogram taken 7 years before admission showed no abnormalities. Serum ACE and lysozyme levels were high: 29.9 IU/l and 14.1 micrograms/ml, respectively. 67Ga scintigraphy showed diffuse uptake in both lung fields. The PPD skin test was negative, and repeated sputum smears and cultures were negative for pyogenic bacteria and acid-fast bacilli. Examination of transbronchial lung biopsy and skin biopsy specimens confirmed the diagnosis--they showed noncaseating epithelioid granulomas with giant cells and a negative reaction of the stain to acid-fast bacilli, which are compatible with sarcoidosis. The patient was given 30 mg/d of prednisone orally. The dyspnea and eruption were clearly alleviated, although there was little roentgenographic regression of cystic or fibrotic changes. There have been only a few reports of cystic and fibrotic changes early in the course of sarcoidosis. The cystic lesions in this case were probably secondary pulmonary cavities caused by the contracting and obstructive changes related to pulmonary fibrosis.

Adult↗
PubMed1995

[Calcium metabolism in porcine liver transplantation].

The influence of warm ischemia on calcium metabolism in liver transplantation (LTX) was investigated using temporary portal vein arterialization (PA) technique. Group I pigs were added no warm ischemia (n = 6). In group II, donors were killed by KCl, and the livers were left in situ for 60 min (n = 6). After anastomosing the suprahepatic vena cava, revascularization was carried out employing PA. Initial reperfused blood was collected through the infrahepatic vena cava. All pigs survived more than 4 days in group I, whereas all died within 2 days in group II. In group II, Ca2+ levels of initial reperfused blood were significantly lower than those of arterial blood. Ca2+ levels of initial reperfused blood in group II were significantly lower than those in group I. Within 90 min after revascularization, biliary output and biliary calcium content and excretion in group I recovered to 30%, 100% and 40% of normal, respectively, but in group II only 2 animals could excrete bile. In conclusion, in the liver with 60 min warm ischemia, Ca2+ influx occurred immediately after revascularization followed by decreased calcium excretion in bile, which suggested that accumulation of calcium might be one of the causes of warm ischemic injury.

Animals↗
PubMed1995

[Roles of Mac-1, endogenous TNF-alpha, and IFN-gamma in pathogenesis of hepatic warm ischemia-reperfusion injury].

The roles of neutrophil Mac-1 (CD11b/18) adhesion molecule, TNF-alpha and IFN-gamma in hepatic warm ischemia-reperfusion injury (IRI) were investigated with a newly established mouse model. Blood supply to the left lateral and the median lobe of the liver was interrupted with an atraumatic clip for 50 minutes. From 1 hour to 24 hours after reperfusion, TNF-alpha in the ischemic liver tissue was detected. IFN-gamma was not detected in ischemic liver tissue and blood. Pretreatment with anti-mouse Mac-1 monoclonal antibody (mAb) diminished the plasma GPT level, area of necrosis, and number of myeloperoxidase positive cells in ischemic liver lobe at 24 hours after reperfusion. Pretreatment with anti-mouse TNF-alpha or anti-mouse IFN-gamma mAb did not affected any parameters. From these results, Mac-1 was considered to play an important role in a hepatic warm IRI. However, TNF-alpha and IFN-gamma were not considered to play a pivotal role in the pathogenesis of the injury and in the regulation of the neutrophils adhesion via Mac-1.

Animals↗
PubMed1995

Effects of BQ-485, a selective ETA antagonist, on endothelin-mediated vasomotion in rat coronary vascular beds.

The effects of BQ-485, a selective endothelin (ET)-A receptor antagonist, on the vasomotion induced by a low dose of ET were investigated. In the isolated rat heart perfused with Krebs-Henseleit solution at a constant flow, intracoronary bolus injection of ET-1 or ET-3 (10 pmol) elicited a rapid transient decrease, followed by a slight sustained increase, in the coronary perfusion pressure (CPP). The decrease in CPP induced by ET-1 was similar in magnitude to (approximately 30%) but shorter in duration than that induced by ET-3. Pretreatment of the heart with saponin (30 micrograms/ml) to denude the coronary endothelium abolished the decrease and markedly enhanced the increase in CPP induced by ETs, indicating that the vasorelaxing action of ETs is endothelium-dependent. The selective ETA receptor antagonist BQ-485 (1 microM) significantly prolonged the duration of the ET-1-induced decrease in CPP, made the vasodilatation by ET-1 indistinguishable from that by ET-3, and eliminated the subsequent increase in CPP. In the saponin-treated heart, BQ-485 also eliminated the ET-1-mediated increase in CPP. These findings suggest that, in rat coronary vascular beds, a low dose of ET-1 elicits vasoconstriction and endothelium-dependent vasodilatation through the ETA receptor on the vascular smooth muscle and presumably the ETB receptor on the endothelium, respectively. Furthermore, it is expected that selective ETA receptor antagonists, including BQ-485, may be able to protect the heart against ET-1-induced coronary spasm in situations, such as hyperlipidemia or artherosclerosis, in which the release and/or function of endothelium-derived vasorelaxing substances is impaired.

Animals↗