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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 235 records · Page 13Linked to original sources
PubMed1997

Setting properties of alginate impression materials in dynamic viscoelasticity.

The viscoelastic properties of three alginate impression materials were investigated. A landmark of working time was calculated using a raw phase-time curve. A landmark of setting time was calculated from an inflection point of the divided difference of the first order in the share modulus-time curve. As a result, the working time was common at the point of delta = 45 degrees in variable frequencies. The mean value was obtained with less deviation. The setting times obtained were similar for variable frequencies. The mean values showed a distinct difference for each impression material.

Alginates↗
PubMed1997

Antifungal effect of zeolite-incorporated tissue conditioner against Candida albicans growth and/or acid production.

A new antimicrobial material, Ag-zeolite (Zeomic), was combined with a commercial tissue conditioner (GC-Soft Liner (GC); 1-5%) and, through monitoring the pH of the growth medium, examined for effects on the in vitro growth and/or acid production of Candida albicans on protein-free and saliva-coated specimens. The effect of incorporation of this agent on the physical property of the lining material was also examined according to the ISO penetration test. Comparison studies were carried out using GC, Coe Comfort (CC) or undecylenate combined GC (1-5%) specimens. Although the pH changes in the media varied depending upon the materials on which the Candida was grown, reverse sigmoidal pH curves were observed with most samples. As compared with GC, the soft lining materials showed, to some extent, an inhibitory effect on the acid production and/or the growth of C. albicans. These inhibitory effects consisted of a delay in the onset of rapid pH decline, decreases in the rate of pH change and increases in minimum pH. In most cases, the inhibitory effects of test specimens were dose-dependent, and zeolite specimens showed a significantly higher antifungal effect, followed by CC and undecylenate-combined GC; GC showed the least antifungal effect. The inhibitory effects of these materials on fungal growth were decreased by the presence of a saliva-coat, particularly with zeolite specimens and CC. However, four of eight 5%-Zeomic specimens still exhibited perfect growth inhibition in the presence of the salivary pellicle. Furthermore, test specimens containing 2-5% Zeomic showed a significantly greater effect on the delay in rapid decline of pH, as compared with the other specimens examined. In addition, the significantly higher minimum pH was observed where the yeasts were grown on 4%- and 5%-Zeomic specimens. The physical properties of all the test specimens conformed with the ISO standard as examined by penetration test. These results taken together suggest that an antimicrobial zeolite-combined tissue conditioner would be a potential aid in denture plaque control.

Acids↗
PubMed1997

Wounding changes the spatial expression pattern of the arabidopsis plastid omega-3 fatty acid desaturase gene (FAD7) through different signal transduction pathways.

The Arabidopsis FAD7 gene encodes a plastid omega-3 fatty acid desaturase that catalyzes the desaturation of dienoic fatty acids in membrane lipids. The mRNA levels of the Arabidopsis FAD7 gene in rosette leaves rose rapidly after local wounding treatments. Wounding also induced the expression of the FAD7 gene in roots. To study wound-responsive expression of the FAD7 gene in further detail, we analyzed transgenic tobacco plants carrying the -825 Arabidopsis FAD7 promoter-beta-glucuronidase fusion gene. In unwounded transformants, FAD7 promoter activity was restricted to the tissues whose cells contained chloroplasts. Activation of the FAD7 promoter by local wounding treatments was more substantial in stems (29-fold) and roots (10-fold) of transgenic plants than it was in leaves (approximately two-fold). Significant induction by wounding was observed in the overall tissues of stems and included trichomes, the epidermis, cortex, vascular system, and the pith of the parenchyma. Strong promoter activity was found preferentially in the vascular tissues of wounded roots. These results indicate that wounding changes the spatial expression pattern of the FAD7 gene. Inhibitors of the octadecanoid pathway, salicylic acid and n-propyl gallate, strongly suppressed the wound activation of the FAD7 promoter in roots but not in leaves or stems. In unwounded plants, exogenously applied methyl jasmonate activated the FAD7 promoter in roots, whereas it repressed FAD7 promoter activity in leaves. Taken together, wound-responsive expression of the FAD7 gene in roots is thought to be mediated via the octadecanoid pathway, whereas in leaves, jasmonate-independent wound signals may induce the activation of the FAD7 gene. These observations indicate that wound-responsive expression of the FAD7 gene in aerial and subterranean parts of plants is brought about by way of different signal transduction pathways.

Acetates↗
PubMed1997

Glutathione metabolism in mice is enhanced more with hapten-induced allergic contact dermatitis than with irritant contact dermatitis.

Cutaneous inflammation induced by electrophilic compounds involves irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD). Reduced glutathione (GSH) and related thiols have been postulated to play important roles in detoxification of electrophilic xenobiotics, protection of tissues against reactive oxygen species, and modulation of immunologic functions in normal and diseased subjects. The dynamic aspects of GSH metabolism, however, and its significance in patients with ICD and ACD remain to be clarified. The current study was carried out to elucidate the pathogenesis and possible involvement of GSH in both types of inflammation. Normal mice and mice sensitized with dinitrochlorobenzene (DNCB) were challenged by cutaneous administration of DNCB, and changes in GSH metabolism in skin and liver were determined. Kinetic analysis revealed that 24 h after challenge with DNCB, levels of hepatic glutathione and its secretion increased more markedly in the sensitized mice than in the unsensitized animals. Administration of buthionine-L-sulfoximine (BSO), a specific inhibitor of GSH synthesis, inhibited the increase in glutathione levels in the liver and the skin of both groups. Histologic examination revealed that cutaneous inflammation was enhanced by BSO more significantly in mice with ACD than with ICD. These results suggest that GSH might play an important role in the suppression of the immune reaction in mice with ACD.

Animals↗
PubMed1997

Early hepatocellular carcinoma macroscopically resembling adenomatous hyperplasia: pathological resemblance to carcinoma-in-situ.

The pathological features of 11 nodules of early hepatocellular carcinoma (EHCC) were studied. Their macroscopic features resembled those of adenomatous hyperplasia and differed from those of advanced hepatocellular carcinomas (AHCC). The EHCC extended along the hepatic lobular structure and lacked expansive growth. The endothelial cells in the sinusoids of EHCC did not react to Ulex europaeus agglutinin 1 (UEA1) like adenomatous hyperplasia or other liver parenchyma, whereas the endothelial cells in the AHCC did react to UEA1. Immunohistochemically, CD68-positive Kupffer cells were noted in the sinusoids of EHCC, whereas in the AHCC Kupffer cells were not seen. Tumor emboli in the portal vein and intrahepatic metastases were not identified in EHCC, which seemed to be carcinoma-in-situ or a microinvasive stage of hepatocarcinogenesis.

Adenoma↗
PubMed1997

An association of human T-cell lymphotropic virus type I infection with vascular dementia.

Subjects ranging in age from 50 to 89 years old, either with or without dementia were studied by both ELISA for anti-human T-cell lymphotropic virus type I (HTLV-I) gag 100-130 antibody and by cranial CT in order to clarify the relationship between HTLV-I infection and dementia. The frequency of anti-HTLV-I antibody was found to be significantly higher in the patients with dementia (24/130, 18.5%) than in those without dementia (11/139, 7.9%) (P=0.0169). Among the various types of dementia, HTLV-I seropositivity was found to be significantly associated with vascular dementia (11/48, 23%) (P=0.0087), but not with Alzheimer type dementia. In addition, HTLV-I seropositivity was also associated with Babinski sign, and the severity of cerebral infarction, ventricular dilatation and periventricular lucency on CT. The presence of HTLV-I therefore appears to be one of the risk factors for vascular dementia in HTLV-I endemic areas.

Adult↗
PubMed1997

Ambulatory blood pressure monitoring in diagnosing a pheochromocytoma of the urinary bladder. A case report.

A patient is presented in whom the preoperative diagnosis of an intravesical pheochromocytoma was facilitated by noninvasive ambulatory blood pressure monitoring. A fifty-two-year-old Japanese man suffered headache and palpitation after micturition. Cystoscopy revealed an intravesical tumor. To investigate whether his symptoms were associated with an elevation of blood pressure, the authors monitored his ambulatory blood pressure automatically for twenty-four hours. The patient was also instructed to activate the recording manually upon the onset of symptoms. As a result, elevations of blood pressure were apparent following micturition. The twenty-four-hour urinary excretion of norepinephrine was elevated on the day of the blood pressure monitoring. Pheochromocytoma was suspected and was confirmed by histopathologic studies following the operation. Thus, ambulatory blood pressure monitoring may be useful in detecting the transient hypertension induced by micturition, which can provide preoperative evidence of pheochromocytoma of the urinary bladder.

Blood Pressure Monitoring, Ambulatory↗
PubMed1997

Spinocerebellar ataxia type 1 and familial spontaneous pneumothorax.

We report two siblings with spinocerebellar ataxia type 1 (SCA1) who experienced frequent episodes of spontaneous pneumothorax. Radiologic findings indicated underlying degenerative changes in the lungs. This suggests a possible pathophysiologic relationship between SCA1 and familial occurrence of spontaneous pneumothorax.

Adult↗
PubMed1997

The case fatality rate of methicillin-resistant Staphylococcus aureus (MRSA) infection among the elderly in a geriatric hospital and their risk factors.

From April 1991 to March 1993, there were 49 elderly patients with methicillin-resistant Staphylococcus aureus (MRSA) infection in a geriatric hospital in Fukuoka, Japan. The retrospective study was carried out in order to evaluate the various factors which may influence the case fatality rate of MRSA infection among the elderly. Among them, 33 patients (67.3%) died while only 16 patients became culture-negative for MRSA and discharged after recovering from MRSA infection. A univariate analysis revealed that male sex (odds ratio [OR] = 12.25, 95% confidence interval [CI] = 2.80-53.55), hypoalbuminemia (OR = 3.83, 95% CI = 1.11-13.21) and an excessive usage of antibiotics (OR = 6.67, 95% CI = 1.70-26.09) were risk factors for death among the patients with MRSA infection. In a multivariate analysis, male sex and an excessive usage of antibiotics were still risk factors while hypoalbuminemia was not. However, hypoalbuminemina was more common in male patients than female patients (78.3% vs. 42.3%, p < 0.05). These findings suggest that the case fatality rate of MRSA infection may be high and also suggest that the elderly with MRSA infection who had hypoalbuminemia and/or received many antibiotics may have a poor prognosis.

Aged↗
PubMed1997

Hemarthrosis of the knee and bone contusion.

We present five patients with acute traumatic hemarthrosis of the knee who also had hemorrhage within the bone marrow around the knee detected by magnetic resonance imaging. No additional bony, ligamentous, meniscal or osteochondral injuries were evident from clinical examination, initial and repeated plain radiographs, or magnetic resonance imaging. The main symptoms were sharply localized pain and tenderness of the contused area. When hemarthrosis was demonstrated at the first office visit, three cases had fat droplets in the blood. Two patients with hemarthrosis of the knee undergoing arthroscopy showed no obvious lesions of intra-articular structures. Instead they showed congestion of the joint capsule located in accordance with the traumatic episode. Magnetic resonance imaging demonstrated marrow abnormalities as diffusely low and high signal intensity areas in T1-weighted and T2-weighted images, respectively, in locations consistent with the traumatic episode and the symptoms. These disappeared within an average of 13 weeks (range in 4 cases, 12 to 16 weeks). These findings were considered diagnostic of bone contusion. Symptom duration was about 2 weeks in all cases. In conclusion the clinician should consider the possibility of coexisting bone contusion in cases of acute traumatic hemarthrosis of the knee with no evidence of bone or intra-articular lesions on clinical examination and conventional radiographs.

Adolescent↗
PubMed1997

[The pharmacokinetics of D-lactate, L-lactate and acetate in humans].

In this study, the pharmacokinetics of D-lactate, L-lactate and acetate were investigated in 36 adult surgical patients. After induction of general anaesthesia, the subjects received intravenous injection of either 5 mmoles of D-lactate and 5 mmoles of L-lactate simultaneously (Group DL), 10 mmoles of L-lactate (Group L), or 10 mmoles of acetate (Group A). Serial arterial blood samples were obtained before the injection, and 3, 5, 7, 9 and 11 minutes after the infusion of each preparation. Plasma concentrations of D-lactate, L-lactate and acetate were measured by high performance liquid chromatography, enzymatic analysis and spectrophotometry. The pharmacokinetic parameters; distribution volume (Vd) and half-life (t1/2) were calculated with a one-compartment model from the incremental plasma concentration decay curve after administration. In Group DL, there were no differences between D-lactate and L-lactate in Vd and t1/2. Also, between L-lactate in Group DL and that in Group L, there were no differences in Vd and t1/2. The Vd and T1/2 of acetate, however, were smaller than those of L-lactate in Group L. We conclude that the pharmacokinetics of D-lactate is similar to those of L-lactate, and that acetate may be metabolized more rapidly than L-lactate.

Acetic Acid↗
PubMed1997

[Evaluation of left ventricular ejection fraction using an automated contour tracking method: comparison with equilibrium radionuclide angiography].

A recently developed contour tracking method provides automated edge detection of left ventricular endocardium without a region of interest. The accuracy of this automated contour tracking (ACT) method in the evaluation of left ventricular ejection fraction was assessed in 20 patients (16 males and 4 females, mean age 58 years) using both the ACT method and equilibrium radionuclide angiography. Ejection fractions measured by the ACT method correlated well with those measured by equilibrium radionuclide angiography (y = 0.8x + 11.9, r = 0.91, SEE = 4.0%, p < 0.01). The ACT method provides an accurate estimate of left ventricular ejection fraction.

Echocardiography↗
PubMed1997

[Prognosis and prognostic factor after extended lymphadenectomy in lung cancer].

From 1984 to 1994, 418 patients were received surgery for the lung cancer in our center. Of them, 178 patients were underwent extended lymphadenectomy. Fifty six of the 178 were histologically proven N2 of N3 alpha disease after surgery. Extended lymphadenectomy means R2b lymphadenectomy including the left tracheobronchial node dissection for the right lung cancer and R3 (bilateral mediastinal lymphadenectomy through a median sternotomy) for the left. In the 56 patients, we examined the location and frequency of metastases to the mediastinal lymph nodes and the relationship between some clinical factors (pT, number of metastatic station, clinical staging of the lymph node (CN), histological type, contralateral mediastinal lymph nodes metastases) and prognosis. Most of the pN2 patients of the right lung cancer showed ipsilateral mediastinal lymph nodes metastases and 25 percent of the patients showed the spread to N2b mediastinal modes. The patients of the left lung cancer showed higher incidence of contralateral mediastinal lymph nodes metastases than the patients of the right lung cancer. The five years survival rate of all pN2 patients (N = 39) was 48%, and T1 or T2-N2 patients (N = 22) was 67%. On the other hand, all T4 N2 patients (N-9) died within 3 years after operation. There was no significant difference in postoperative survival between the patients with single station metastasis (N = 20) and multistation metastases (N = 30, including 11 cases with N3 alpha). The five years survival rate of all the patients with multistation metastases was 45%, and that of T1 or T2 multilevel (N = 20) was 65%. There was significant difference in postoperative survival between the patients with CN0-pN2 and CN2-pN2 (p < 0.05). The five years survival of CN0-pN2 patients (N = 14) was 85% and four years survival rate of CN2 pN2 patients (N = 19) was 30%. Among the patients with T1 or T2 tumor, however, there was no significant differences in postoperative survival between CN0-pN2 patients and CN2 pN2 patients. There was no difference in postoperative survival between adenocarcinoma and squamous cell carcinoma (5 years survival: 56%, 43%). In conclusion, extended lymphadenectomy has brought a good prognosis in the patient with T1 or T2 in spite of presence of CN2 or multistation N2. The patients with contralated mediastinal metastases (N3 alpha) showed good prognosis after R3 (5 years survival: 100%) in the patients with the left lung cancer (N = 6). But the N3 alpha patients of right lung cancer showed poorer prognosis (3 years survival: 30%) after R3 (N = 5) than the left. It suggested that R3 lymphadenectomy was significant and beneficial for the left lung cancer patients with N3 alpha but controversial for the right.

Aged↗
PubMed1997

[A case of bicuspid aortic valve stenosis with single coronary artery].

A 62-year-old female who had a complaint of palpitation was diagnosed as bicuspid aortic stenosis and left single coronary artery by the echocardiographic examination, cardiac catheterization study and coronary artery angiography. Aortic valve replacement was performed and the patient was discharged 22 days after surgery with good post-operative course. Preoperative coronary artery angiography was important in the case of aortic valvular disease.

Aortic Valve↗
PubMed1997

[Plasma macrophage colony-stimulating factor, granulocyte macrophage colony-stimulating factor and granulocyte colony-stimulating factor levels in continuous ambulatory peritoneal dialysis patients].

From a pathophysiological perspective, several studies have been performed on cytokines in chronic renal failure patients treated with continuous ambulatory peritoneal dialysis (CAPD). Because the peritoneal macrophages in CAPD patients produce some cytokines and the urinary secretion route for cytokines lost in those patients, CAPD patients are considered to have different plasma cytokine levels. Among the various cytokines, research on certain inflammatory cytokine levels has been reported. In studies of CAPD patients, peripheral blood and dialysate can be used as specimens. There are two methods of research. One involves determining the cytokine concentration in specimens and culture supernatant, while the other is to determine the mRNA expression of mononuclear cells in specimens and cultured mononuclear cells. The plasma levels of macrophage colony stimulating factor (M-CSF), granulocyte macrophage colony stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) were measured in CAPD patients without peritonitis. Plasma M CSF, GM CSF and G-CSF levels in CAPD patients were higher than those in healthy volunteers (p < 0.0001).

Adult↗
PubMed1997

[Progressive supranuclear palsy with macular degeneration--report of three cases].

Three cases of progressive supranuclear palsy (PSP) with decreased visual acuity were reported. Case 1 was a 50-year-old man, case 2 a 60-year old woman, and case 3 a 66-year-old woman. They all had vertical gaze palsy and unexplained falls, and were diagnosed as PSP by NINDS-SPSP clinical criteria. All cases had symptoms of difficulty in vision; therefore, detailed ophthalmological tests were performed. Ophthalmoscopic findings of macula revealed atrophy in case 1 and 2, and brownish discoloration in case 3. Fluorescein fundus angiography done in case 1 showed abnormal staining at the macula. Multifocal electroretinography performed in case 3 showed absence of big response in the macula. These results indicated macular degeneration. None of three cases had cataract. And visual evoked potentials of case 2 and 3 showed prolonged P100 latency. From these results, we suspected that decreased visual acuity of our cases were due to macular degeneration and difficulty to catch the object at the fovea because of gaze palsy. There had been no reports of macular degeneration with PSP, but we might have overlooked these findings, because of dementia, gaze palsy, and apraxia of lid opening. The possibility of macular degeneration is raised as a part of neurological signs is PSP.

Aged↗