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Biomedical subjects

S Yamada

Publications and source records attributed to S Yamada.

At least 199 records · Page 11Linked to original sources
PubMed2001

[Contrast agent improves diagnostic value of dobutamine stress echocardiography].

OBJECTIVES: Suboptimal endocardial definition reduces the diagnostic value of stress echocardiography for coronary artery disease, but intravenous infusion of a left ventricular contrast agent (Albunex) may enhance endocardial border delineation and improve the diagnostic value of dobutamine stress echocardiography. METHODS: Fifty-six patients, 38 with myocardial infarction, 16 with angina pectoris and two normal subjects, were enrolled in this study. Dobutamine was infused in scalar doses of 5 to 40 micrograms/kg/min. Intravenous infusion of Albunex (0.15 ml/kg) was administered at rest and during peak dobutamine stress during monitoring of the apical four-chamber view. The left ventricle in the apical four-chamber view was divided into six segments and an endocardial delineation score of 0 to 3 (none to excellent visualization) was given to each segment. RESULTS: Endocardial delineation score was increased after Albunex infusion from 2.0 to 2.3 in the basal-septal, 2.0 to 2.4 in the mid-septal, 1.1 to 1.8 in the apical-septal, 0.7 to 1.2 in the apical-lateral, 0.9 to 1.6 in the mid-lateral, and 1.2 to 1.9 in the basal-lateral segments during peak dobutamine administration. Endocardial border resolution in the lateral wall showed greater improvement than in the septal wall after Albunex infusion. Diagnostic values in the left anterior descending artery territory failed to improve with Albunex infusion (sensitivity 82% to 89%, specificity 94% to 89%, and accuracy 86% to 89%), whereas a higher diagnostic accuracy was noted in the left circumflex artery territory with Albunex compared to without Albunex (sensitivity 63% to 81%, specificity 88% to 98%, and accuracy 80% to 93%, p < 0.05). CONCLUSIONS: Contrast agent improves the diagnostic accuracy of dobutamine stress echocardiography in the left circumflex artery territory.

Aged↗
PubMed2001

The biochemical analysis of neurotransmitters in central neurocytomas.

Central neurocytomas are rare benign intraventricular tumours composed of small round synaptophysin-positive cells, suggesting a neuronal origin of these tumour cells. Although past electron microscopic studies demonstrated synaptic vesicles in the synapse of central neurocytomas, the kinds of neurotransmitters in central neurocytomas have never been identified. In this study we analyzed neurotransmitters in an attempt to clarify the tumorigenesis of central neurocytomas. We studied frozen central neurocytoma specimens from four patients. The tissue levels of glutamate and GABA (gamma-aminobutyric acid) in the tumours were determined by gas chromatography-mass spectrometry (GC-MS) using a selected ion monitoring method. The tissue levels of acetylcholine, choline, catecholamines and metabolites of catecholamines in the tumours were measured by high-performance liquid chromatography combined with electrochemical detection. Choline was found in extremely high concentration in all central neurocytomas when compared with levels in controls. In one central neurocytoma, GABA was found in extremely high concentration compared with controls. In all central neurocytomas, glutamate was found in lower or identical concentrations compared with controls. In all central neurocytomas and controls, dopamine and catecholamine concentrations were extremely low. These results indicated that the histogenesis of central neurocytomas begins with the subependymal stem cells, which have the potential to differentiate into cholinergic or GABA neurons.

Adult↗
PubMed2001

Low-dose dobutamine electrocardiograph-gated myocardial SPECT for identifying viable myocardium: comparison with dobutamine stress echocardiography and PET.

UNLABELLED: The identification of severely dysfunctional but viable myocardium is of particular importance for the selection of patients with depressed left ventricular function who will benefit from coronary revascularization. Assessment of inotropic reserve with dobutamine has recently been used for this purpose. This study compared the accuracy of low-dose dobutamine stress gated myocardial SPECT (DS SPECT) with the accuracy of dobutamine stress echocardiography (DSE) and resting perfusion SPECT for the identification of viable myocardium in patients with previous myocardial infarction. METHODS: Resting and low-dose dobutamine (7.5 microg/kg/min) gated (99m)Tc-tetrofosmin SPECT and echocardiography and resting (18)F-FDG PET were prospectively studied in 23 patients with previous myocardial infarction and severely depressed regional function. Twenty-one of them were successfully studied with each technique. The left ventricular wall was divided into 14 segments to assess wall motion using a 5-point scale. PET viability was defined as FDG uptake >/= 50% of the maximum uptake in a region with normal wall motion. For DS SPECT and DSE studies, viable myocardium was defined as hypokinetic areas with > or = 1 point improvement in wall motion. For resting perfusion SPECT, viable myocardium was defined as hypokinetic areas with a relative uptake > or = 50% of the maximum uptake. RESULTS: Of a total of 294 segments, 55 had severe resting dyskinesis. Thirty-four segments were identified as viable on FDG PET, and 21 segments were identified as nonviable. Eleven segments were inadequately visualized with DSE, including 5 segments in the apex. Sensitivities (78% vs. 76%) and specificities (94% vs. 100%) were similar for DSE and DS SPECT, with a concordance of 86% (kappa = 0.72). DS SPECT and perfusion SPECT did not significantly differ with respect to sensitivities (76% vs. 85%, respectively). However, specificity was significantly higher for DS SPECT than for perfusion SPECT (100% vs. 52%, respectively, P < 0.05). CONCLUSION: This study indicated that DS SPECT correlates well with DSE in the assessment of viability. In addition, gated SPECT can evaluate regional wall motion, even in areas inadequately assessed by echocardiography. DS SPECT may also provide additional information for identifying viable myocardium, which is often overestimated by routine perfusion scans.

Aged↗
PubMed2001

[Tubulointerstitial nephritis in the case of acute renal failure from sepsis after a cat bite].

Acute tubulointerstitial nephritis is associated with a variety of causes, such as drug interaction, and infectious or immunological mechanisms. We describe a patient who suffered from sepsis, septic shock, disseminated intravascular coagulation(DIC), hepatic failure and renal failure after receiving a bite from her house cat. The causes of her acute renal failure were initially thought to be due to circulatory failure with hypotensive shock, decrease in renal blood flow with fibrin formation by DIC, or microangiopathy such as hemolitic uremic syndrome. However, the renal biopsy on the 60th hospital day indicated tubulointerstitial nephritis, which was recognized by the presence of patchy and focal mononuclear small cell infiltration with invasion to the tubular epithelium. We concluded that prolonged renal failure was caused by tubulointerstitial nephritis. The cause of tubulointerstitial nephritis was not identified. Tubulointerstitial nephritis should be taken into consideration when the recovery from acute renal failure is slow.

Acute Kidney Injury↗
PubMed2001

[Hemophagocytic syndrome with hemophagocytes in the peripheral blood].

A 79-year-old man developed a high fever, facial erythema, anemia and thrombocytopenia during conservative therapy for ischemic colitis. Peripheral hemophagocytes (PHP) were identified in smear specimens of peripheral blood, and hemophagocytes also showed proliferation in the bone marrow. After treatment with steroid and antibiotics under a diagnosis of bacteria-associated hemophagocytic syndrome, the patient recovered rapidly. Although the prognosis of hemophagocytic syndrome (HPS) depends on the underlying disease, any delay in diagnosis can sometimes result in a poor outcome in cases of infection-associated hemophagocytic syndrome. In the present case, early diagnosis of bacteria-associated hemophagocytic syndrome was made by detection of PHP. The appearance of PHP in virus-associated hemophagocytic syndrome (VAHS) and after administration of macrophage colony stimulating factor has been described. However, the significance and cytological characteristics of PHP have been unknown. In this report, we propose that PHP can be a useful indicator for early diagnosis of HPS, and we report 7 additional cases in which the PHP was detected retrospectively. The cytological characteristics and biological significance of PHP are discussed.

Aged↗
PubMed2001

Immunochemical detection of a lipofuscin-like fluorophore derived from malondialdehyde and lysine.

The accumulation of fluorescent age pigment or lipofuscin is a frequently observed age-associated cellular alteration in a variety of postmitotic cells of many species. These pigments are observed within granules composed, in part, of damaged protein and lipid. Modification of various biomolecules by aldehyde products of lipid peroxidation is believed to contribute to lipofuscin and ceroid formation. In the present study, we raised a monoclonal antibody (MAb 1F83) directed to the malondialdehyde-modified protein and identified a lipofuscin-like dihydropyridine fluorophore as the major epitope. This antibody was used to conclusively demonstrate that the fluorophore forms on oxidatively modified low density lipoproteins. In addition, we demonstrated that the materials immunoreactive to MAb 1F83 indeed constituted the atherosclerotic lesions, in which intense positivity was associated primarily with macrophage-derived foam cells. The results of this study suggest that the reaction between the lipid peroxidation-derived aldehyde and primary amino groups of protein might represent a process common to the formation of the lipofuscin-like fluorophore during aging and its related diseases.

Animals↗
PubMed2001

[Simple method of stereotactic radiotherapy without stereotactic body frame for extracranial tumors].

Thirty-five patients with metastatic lung cancer(46 lesions) and twenty patients with primary lung cancer (21 lesions) have been treated with a simple method of stereotactic radiotherapy (SRT) without stereotactic body frame. Tumor size ranged from 1-4 cm in diameter. We used Vac-Lok cushion(Med-Tek) as a immobilization system. To be sure to include the respiratory movement of tumor to planning target volume(PTV), every patients were examined by fluoroscopy and radio-opaque catheters with the same length of tumor movement were attached on the anterior and lateral chest wall before CT simulation. A gold grain was implanted into a tumor that was invisible on fluoroscopy, as a radiomaker. Protocol of 60 Gy/8 fractions/2 weeks and 45 Gy/3 fractions/3-6 days were mainly used. The median follow-up period was 15 months for primary lung cancer and 19 months for metastatic lung cancer. Local control rates were 91% for metastatic lung cancer, 89% for primary lung cancer and 85% for T1, 2N0M0 cases. All patients developed mild pneumonitis or fibrosis about 4.5 months after SRT just in the treatment volume. Only three patients was symptomatic.

Clinical Trials as Topic↗
PubMed2001

[Complications of stress echocardiography].

BACKGROUND: Stress echocardiography is an established clinical testing method and is accurate for the detection of coronary artery disease. Despite its widespread use, the safety of stress echocardiography has not been sufficiently documented in Japanese laboratories. OBJECTIVES: The feasibility, safety, complications and side effects of stress echocardiography were assessed for detecting myocardial ischemia in patients with suspected coronary artery disease. METHODS: 1,866 patients who underwent dobutamine echocardiography(n = 897), exercise echocardiography(n = 722), and dipyridamole echocardiography(n = 247) were prospectively studied from November 1990 to April 2000. Dobutamine was administered intravenously at 5, 10, 20, 30, 40 micrograms/kg/min in 3-minute intervals. Exercise echocardiography used the supine ergometer, starting at 50 W and increasing gradually by 25 W at 3-minute intervals to the maximum of 150 W. Dipyridamole was administered intravenously at 0.14 mg/kg/min for 4 min. After a 4-minute observation period, the drug was re-administered at the same dose for 2 min. RESULTS: The most common side effects under each stress were ventricular premature beats in 34.1% (dobutamine echocardiography), ventricular premature beats in 14.4%(exercise), and headache in 24.3% (dipyridamole). Serious side effects occurred in one patient(0.05%). The case of acute myocardial infarction was caused by dipyridamole echocardiography, and the patient needed emergency coronary angioplasty. Seven patients needed other drug therapy for nonsustained ventricular tachycardia(one), paroxysmal supraventricular tachycardia(two), sinus bradycardia(three), and bronchial asthma(one). There was no incidence of death, shock, or ventricular fibrillation, sustained ventricular tachycardia or other conditions requiring inpatient observation during stress echocardiography. CONCLUSIONS: Stress echocardiography is a reasonable, safe method for determining myocardial ischemia, but may be associated with minor, self-limiting side effects.

Aged↗
PubMed2001

Ureteral fibroepithelial polyp associated with urolithiasis induced by steroid therapy in a child: a case report.

A 14-year-old boy complained of left flank pain. He had been given high-dose corticosteroid therapy for chronic inflammatory demyelinating polyneuropathy (CIDP). Retrograde pyelography revealed irregular defects at the left ureteropelvic junction (UPJ), and ureteroscopy demonstrated ureteral polyp. The polyp was removed and histologically diagnosed as fibroepithelial polyp. Hypercalciuria due to the corticosteroids and bedridden was assumed to have been a causative factor in the stone formation. To our knowledge, this is the first report of a ureteral fibroepithelial polyp in children associated with urolithiasis, and associated with CIDP.

Adolescent↗
PubMed2001

On the biopsychosocial model: the example of political economic causes of diabetes in the Marshall Islands.

Biomedical reductionism, the unwritten theory underlying the practice of medicine, is being supplanted by the biopsychosocial model. The explanatory power of the biopsychosocial model, however, is hampered by an inadequate mechanism to account for the social production of disease. We examine diabetes in the Marshall Islands to explore a conceptual approach that incorporates ecology, history, and political economy into the biopsychosocial model. The use of the Marshall Islands by the United States as testing grounds for nuclear war has led to ecological destruction, population displacement, and economic dependency. The consequence at the biological level has been an epidemic of weight gain, altered metabolism, and diabetes. A political economic perspective reveals that such outcomes are the result of decisions made by those who do not live with these decisions. Such a perspective points the way for social engagement and political work toward justice and health.

Comorbidity↗
PubMed2001

An unusual cause of incontinence.

BACKGROUND: Incontinence is the most common urological symptom of tethered cord syndrome and may present as the earliest sign of this condition. The presence of unexplained incontinence with spinal anomalies, low back and leg symptoms, should raise the suspicion of tethered cord syndrome and lead to a lumbar MRI study, even though only subtle neurological abnormalities are found. OBJECTIVE: This case acts as a timely reminder of the need to be familiar with adult tethered cord syndrome so that an appropriate diagnosis is made promptly. DISCUSSION: The two groups of tethered cord syndrome, group 1 and group 2, are briefly defined; this paper discusses the presenting history of a patient in the first group.

Diagnosis, Differential↗
PubMed2001

[A case of cerebellar glioblastoma with massive cerebellar hemorrhage].

A case is reported of glioblastoma multiforme (GM) of the cerebellum associated with an intracerebellar hemorrhage. A 54-year-old male was admitted to our hospital with sudden onset of headache and nausea. CT scan showed right intracerebellar hemorrhage. The patient received conservative therapy and was discharged without any neurological deficits. However a second cerebellar hemorrhage attacked him ten days after discharge. His level of consciousness deteriorating, he underwent suboccipital craniectomy and the hematoma with the surrounding elastic tissues was excised. There were no findings suggesting hemorrhage within the tumor on the preoperative neuroimagings, but histological examination confirmed GM with massive hemorrhage. To our knowledge, only 2 cases of cerebellar GM with massive hemorrhage have been reported in the literature. Our case indicates cerebellar GM should be taken into account as a possible cause of cerebellar hemorrhage.

Cerebellar Diseases↗
PubMed2001

Attitudes regarding tuberculosis among Samoans.

The research reported here examines knowledge, attitudes, and practices related to tuberculosis (TB) among Samoan immigrants through the use of a focus group. Samoan health workers to discuss participants' explanatory models regarding TB convened a focus group of eight Samoan living in Hawaii. The participants expressed a belief in the extreme contagiousness of TB. This leads to social stigma and isolation. Most agreed that biomedical treatment is necessary. Traditional herbal medicine was seen as adjunct to biomedical treatment. Focus group participants were found to subscribe to largely biomedical explanatory models regarding TB, but belief in traditional medicine also persists. TB was believed to be more transmissible than it actually is. TB continues to be a stigmatized disease.

Attitude to Health↗
PubMed2001

P53 and MDM2 co-expression in tobacco and betel chewing-associated oral squamous cell carcinomas.

Oral cancers of tobacco and betel chewers represents a unique in-vivo model to understand the genotoxic effect of tobacco and betel carcinogens on oncogenes and tumor suppressor genes. Coordinated interactions of p53 and MDM2 play an important role in regulation of critical growth control gene following exposure to DNA damaging agents. The purpose of this study is to determine if the tumor suppressor function of p53 is inactivated by mutation or other alternative mechanisms in carcinogen-induced oral squamous cell carcinoma (SCC), and to investigate the clinicopathological significance of p53 and MDM2 expression. The p53 mutation in oral SCC of tobacco and betel chewers (n=40) was detected by polymerase chain reaction - single strand conformation polymorphism (PCR-SSCP) analysis and immunohistochemistry (IHC) was done to investigate p53 and MDM2 proteins overexpression. The incidence of p53 mutation was relatively low (17.5%), but there was a high prevalence of MDM2 overexpression (72.5%). In the total of 40 cases, IHC phenotype showed p53 positive immunostaining with MDM2 positive immunostaining (p53+/MDM2+) 62.5%, p53 negative immunostaining with MDM2 negative immunostaining (p53-/MDM2-) 15%, p53 positive immunostaining with MDM2 negative immunostaining (p53+/MDM2-) 12.5%, and p53 negative immunostaining with MDM2 positive immunostaining (p53-/MDM2+) 10%. A significant correlation was found between MDM2 and p53 overexpression (p=0.0289). Moreover, p53+/MDM2+ phenotype was significantly associated with poorly differentiated tumors (p= 0.0007). These results conclude that other factors than p53 mutation is likely to be the targets of tobacco/betel carcinogens and MDM2 may play an important role in tobacco/betel chewing-related oral SCCs. Overexpression of MDM2 protein may constitute an alternative mechanism for p53 inactivation.

Areca↗
PubMed2001

Cultural competence: a proposal for physicians reaching out to Native Hawaiian patients.

Many physicians of Native Hawaiian ancestry, as well as others, have noted a cultural gap between themselves and their Native Hawaiian patients. This cultural gap could potentially lead to discordance in the physician-patient relationship, and in turn, result in less than adequate therapeutic outcomes. Native Hawaiian physicians and those who treat Native Hawaiian patients are seeking ways to improve therapeutic relationships. Developing cultural competency in Native Hawaiian physicians and those who treat Native Hawaiian patients may be expected to improve therapeutic relationships. Principles of cultural competency, including increasing awareness of self and others, enhancing one's cultural knowledge base, and developing skills to communicate effectively, could be applied to physician-patient encounters with Native Hawaiian patients. The principles and skills of cultural competency could be learned during the formal and continuing medical education process. Developing an educational system that promotes cultural competency in physicians is necessary to address the health needs of Native Hawaiians and other diverse populations in Hawai'i.

Attitude to Health↗
PubMed2001

Comparisons of psychosomatic health and unhealthy behaviors between cleanroom workers in a 12-hour shift and those in an 8-hour shift.

The General Health Questionnaire (GHQ12) and physical fitness tests were administered to 338 workers in clean rooms producing electronic parts in 12-h shifts. The results were compared to those in 95 workers in 8-h shifts and 284 daytime management, clerical and engineering workers. The 12-h shift workers complained of poor health, dissatisfaction with life and poor recuperation from fatigue more than the 8-h shift workers although the rates of complaints were highest in the daytime workers. The GHQ scores were similar in the two shift groups, and much better than those in the daytime workers. However, the 12-h shift workers showed significantly lower fitness levels than the 8-h shift workers, and the levels were even worse than the daytime workers who had higher mean age and BMI levels compared with the shift workers. The tendency to have sedentary freetime activities and larger alcohol and cigarette consumption were observed in the 12-h shift workers. The 12-h shift work may have contributed to the unhealthy behaviors resulting in lower physical fitness levels. Health promotion services at the workplace should devote greater attention to long-hour shift workers, together with devising the ways to improve working conditions and environments for reducing fatigue at work.

Adult↗