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Biomedical subjects

Y Doi

Publications and source records attributed to Y Doi.

At least 217 records · Page 12Linked to original sources
PubMed1997

[Mechanism of silent myocardial ischemia in elderly patients with coronary artery disease--assessment by dipyridamole thallium scintigraphy].

To evaluate the clinical significance of silent myocardial ischemia in elderly patients with coronary artery disease, 147 patients (aged 65 years and older) underwent coronary angiography and dipyridamole thallium scintigraphy. Seventy-four patients (44 men, 30 women) who showed reversible defects (RD) and ischemic ST depression during scintigraphy were divided into two groups: 13 with silent RD (18%, 12 men, 1 woman), and 61 with painful RD (82%, 32 men, 29 women). Most patients with silent RD were men. The prevalence of myocardial infarction was similar in patients with silent RD (62%) and in patients with painful RD (49%). The prevalence of multivessel disease was also similar in the two groups: 85% in patients with silent RD and 82% in patients with painful RD. Among 38 patients with infarction, 8 had silent RD and 30 had painful RD. The prevalence of RD in the area of infarction was greater in patients with silent RD (63%) than in patients with painful RD (47%), but the difference was not statistically significant. The prevalence of extensive infarction (fixed defects) was greater in patients with silent RD (75%) than in patients with painful RD (30%, p < 0.05). Among 36 patients without infarction, there was no scintigraphic parameter which showed significant difference. Bypass grafting and angioplasty were initially performed in 23% of the patients with silent RD and in 36% of the patients with painful RD (ns). When the two groups were treated medically during the follow-up period of 29 +/- 22 months, the incidences of cardiac events were similar: 10% in patients with silent RD and 13% in patients with painful RD. The prevalence of silent RD is not high in elderly patients with significant coronary artery disease. Compared with the patients with painful RD, those with silent RD were more likely to have an old and extensive myocardial infarction, and they tended to have RD in the area of the infarct.

Aged↗
PubMed1997

[Usefulness of dipyridamole thallium scintigraphy in the diagnosis of coronary artery disease in elderly patients].

Patients suspected of having coronary artery disease (CAD) underwent dipyridamole thallium scintigraphy, exercise electrocardiography, and coronary angiography. Of the 500 patients studied, 163 were at least 65 years old, and 337 were less than 65 years old. Both CAD and multivessel CAD were more common in elderly than in younger patients (81% vs 69%, p < 0.01 for CAD; and 43% vs 26% p < 0.01 for multivessel CAD). In patients without myocardial infarction, the specificity of exercise electrocardiography was lower among elderly patients than among younger patients (52% vs 61%), but the sensitivity was higher (87% vs 75%). In contrast, both the sensitivity and the specificity of dipyridamole thallium scintigraphy were similar in the two age groups (86% vs 87% and 79% vs 74%). Among patients with myocardial infarction and a positive exercise test, reversible defects were equally common in the two age groups (60% vs 58%). The reversible defects were in areas remote from the area of infarction in half of the patients in both groups. Among patients with negative exercise-test results, reversible defects were more common in elderly patients than in younger patients (57% vs 38%). The reversible defects were in the infarcted area in 71% and 79% of these patients, respectively. These results indicate that dipyridamole thallium scintigraphy is a sensitive and specific method for detecting CAD, independent of age. It is particularly useful in identifying myocardial viability in the infarcted area.

Adult↗
PubMed1997

Spontaneous haemothorax caused by costal exostosis.

We report a case of spontaneous haemothorax in a 19 year old boy with an exostosis of the left second rib. It may have been caused by nontraumatic rupture of markedly dilated pleural vessels, as a result of long-standing friction between the exostosis and the pleura. This is the first report of spontaneous haemothorax, without penetrative injury to the pleura or the diaphragm, in a patient with hereditary multiple exostosis.

Adult↗
PubMed1997

[Prognosis for medically treated elderly patients with coronary artery disease: analysis by the Cox model].

The prognostic importance of age among well-known prognostic factors such as extent of coronary artery lesions, cardiac function, and myocardial ischemia was evaluated in 147 elderly patients with coronary artery disease aged 65 years or older who underwent dipyridamole perfusion scintigraphy and coronary angiography. After excluding 32 patients who initially underwent percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG), 115 patients who were initially treated medically were analysed by the Cox model for cardiac events during a mean follow-up period of 29 +/- 22 months. Among the 114 patients who were available for follow-up, nine patients (7.9%) had cardiac events, including five cardiac deaths and four non-fatal cardiac events (requiring PTCA or CABG). When the 114 patients were divided into three age-groups; 53 patients aged 65-69 years, 42 aged 70-74 years and 19 aged 75 years or older, the incidence of cardiac death was highest in those aged 75 years or older. Univariate analysis showed that age of 70 years or older (hazards ratio 15.15, p = 0.004), scintigraphic diffuse slow washout (hazards ratio 8.77, p = 0.002), and triple-vessel or left main trunk disease (hazards ratio 6.36, p = 0.05) were important prognostic factors. Multivariate analysis showed that scintigraphic diffuse slow washout (hazards ratio 6.33, p = 0.05), and triple-vessel or left main trunk disease (hazards ratio 11.94, p = 0.05) were statistically significant as independent prognostic factors. However, when age of 70 years or older was included in the analysis, it showed higher hazards ratio (21.21, p = 0.03) than that of scintigraphic diffuse slow washout (7.36) or triple-vessel or left main trunk disease (5.30). Age of 70 years or older may be a significant prognostic factor in elderly patients with coronary artery disease which has an equivalent importance to the extent of coronary lesions.

Aged↗
PubMed1997

[Surgically treated unruptured sinus of Valsalva aneurysm: a case report].

A 73-year-old man was admitted because of progressive dyspnea. Echocardiography revealed a markedly dilated right sinus of Valsalva and severe aortic regurgitation. Coaptation loss of the aortic valve leaflets was thought to be the cause of regurgitation and congestive heart failure, a rare complication of the unruptured sinus of Valsalva aneurysm. Surgical treatment should be considered to prevent life-threatening heart failure and rupture of the aneurysm even in patients without overt heart failure.

Aged↗
PubMed1997

[Home infusion therapy for cancer patients at a near-terminal stage--analysis of cases who died at home].

To improve the quality of life in cancer patients at a near-terminal stage, we assisted patients to stay home using a system for home infusion therapy (HIT) established at Osaka Prefectural Habikino Hospital in 1994. From April in 1995 to April in 1996, 25 patients were treated at home using the HIT system for longer than 7 days. Thirteen out of 25 patients still stayed at home even at a terminal stage and died in their residences. There was no difference either in the mean age or in the HIT duration between 13 patients who died at home and the remaining 12 patients who were readmitted to their hospitals before death. However, 47% of the patients who died at home had been told their diagnoses by doctors and realized their own prognoses, while only 17% of the patients who died in the hospital knew their diagnoses and prognoses. Seventy-seven percent of the patients who died at home were given home oxygen therapy (HOT), against 33% of the patients who died in the hospital. Furthermore, the patients who died at home were given more intensive care than the patients who died in the hospital, because the former had a larger family than the latter. In conclusion, HIT at a near-terminal stage and death at home may be more readily accepted by patients who know their diagnoses and prognoses and have a large family.

Adult↗
PubMed1997

[Recovery process from myocardial stunning after transient ischemia: assessment with pulsed wave Doppler transmitral flow pattern].

Sustained left ventricular systolic dysfunction after transient myocardial ischemia is well known as "myocardial stunning", but little is known about the recovery in left ventricular diastolic function. Changes in left ventricular systolic and diastolic performance following dobutamine-induced ischemia were investigated in 13 patients with chest pain syndrome and normal coronary arteries (control) and 34 patients with coronary artery disease. Two-dimensional echocardiography and pulsed wave Doppler transmitral flow velocity curves were recorded at baseline, after infusion of a peak dose of dobutamine and at 20 min and 2 hours after dobutamine infusion. In control subjects, left ventricular ejection fraction and the peak early diastolic filling velocity increased at the peak dose of dobutamine. At 20 min after the cessation of dobutamine infusion, these values were restored to the baseline levels. In patients with coronary artery disease, ejection fraction and peak velocity increased at the peak dose of dobutamine but decreased at 20 min after infusion compared with baseline values despite the restoration of heart rate and blood pressure. Although ejection fraction increased at 2 hours compared with 20 min after infusion, peak velocity did not increase. Left ventricular diastolic dysfunction may be sustained longer than systolic dysfunction after transient myocardial ischemia.

Aged↗
PubMed1996

Diagnostic significance of an exercise-induced prominent U wave in acute myocardial infarction.

A prominent U wave induced by exercise testing in patients with anterior wall myocardial infarction is a highly specific but insensitive marker for the narrowing of the left circumflex or right coronary artery, although a U-wave increase alone with or without ST-segment depression may help better identify these coronary artery narrowings. In patients with inferior and/or posterior myocardial infarction, a prominent U wave is regarded as a simple electrocardiographic marker for inferior and/or posterior residual ischemia.

Adult↗
PubMed1996

Tbeta 4 is not a simple G-actin sequestering protein and interacts with F-actin at high concentration.

Thymosin beta 4 is acknowledged as a major G-actin binding protein maintaining a pool of unassembled actin in motile vertebrate cells. We have examined the function of Tbeta 4 in actin assembly in the high range of concentrations (up to 300 micron) at which Tbeta 4 is found in highly motile blood cells. Tbeta 4 behaves as a simple G-actin sequestering protein only in a range of low concentrations (<20 micron). As the concentration of Tbeta 4 increases, its ability to depolymerize F-actin decreases, due to its interaction with F-actin. The Tbeta 4-actin can be incorporated, in low molar ratios, into F-actin, and can be cross-linked in F-actin using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. As a result of the copolymerization of actin and Tbeta 4-actin complex, the critical concentration is the sum of free G-actin and Tbeta 4-G-actin concentrations at steady state, and the partial critical concentration of G-actin is decreased by Tbeta 4-G-actin complex. The incorporation of Tbeta 4-actin in F-actin is associated to a structural change of the filaments and eventually leads to their twisting around each other. In conclusion, Tbeta 4 is not a simple passive actin-sequestering agent, and at high concentrations the ability of Tbeta 4-actin to copolymerize with actin reduces the sequestering activity of G-actin-binding proteins. These results question the evaluation of the unassembled actin in motile cells. They account for observations made on living fibroblasts overexpressing beta-thymosins.

Actin Cytoskeleton↗
PubMed1996

Formation of apatite-collagen complexes.

An apatite-collagen complex was prepared in calcium beta-glycerophosphate solutions at pH 9.0 and 37 degrees C with the purpose of developing new bone substitutes that more closely resemble bone than currently available materials. Reconstituted type I collagen as well as sheet collagen were crosslinked in the presence of alkaline phosphatase and egg-yolk phosvitin. The crosslinked collagens were immersed in daily-renewed calcium beta-glycerophosphate solutions for 2 and 4 weeks to induce the deposition of apatite on the collagen fibers. After 2 weeks of reaction, for example, apatites deposited approximately two times the crosslinked collagen in weight. With reconstituted collagen, the complex showed some elasticity but no apatite was visually observed to detach under deformation with fingers and forceps. The complex, moreover, did not disintegrate when immersed in saline or animal blood. Nevertheless, the complex resorbed with no evidence of cytotoxicity when implanted in muscle tissues. These findings suggest that the apatite-collagen complex prepared would be useful as bone substitutes, especially for periodontal osseous lesion repair and alveolar ridge augmentation.

Alkaline Phosphatase↗
PubMed1996

Self-setting, bioactive, and biodegradable TTCP-DCPD apatite cement.

Tetracalcium phosphate-dicalcium phosphate dihydrate self-setting apatite cement mixed with low-crystallized seed hydroxyapatite is similar to the host bone in degree of crystallinity. The bonding strength of this cement with hydroxyapatite-coated titanium rods was twice that with noncoated titanium and four times that with stainless steel. Histologically, TTCP-DCPD apatite cement incorporated into the tibia of rabbits were degraded, absorbed, and replaced by the normal body trabeculae rapidly. The mechanical strength of the cement disk intercalated into a gap made in the rabbit tibiae increased to 73% of that of the normal tibia at 10 weeks concurrently with the decrease in bone mineral density of the disk toward that of the normal tibia, in which bony replacement of the disk was observed also histologically. These bioactive and biodegradative characters of this cement are due to the similarity of its degree of crystallinity to that of the host bone, and could expand its clinical applications.

Animals↗
PubMed1996

A self-setting TTCP-DCPD apatite cement for release of vancomycin.

Vancomycin (VCM), a methiciline-cefem resistant Staphylococcus aureus (MRSA)-specific antibiotic, was incorporated in a self-setting tetracalcium phosphate (TTCP)-dicalcium phosphate dihydrate (DCPD) apatite cement that hardened isothermally into a hydroxyapatite (HAP) phase with crystallinity similar to that of host bone. Effective release of VCM into PBS lasted for 2 weeks from cements containing 1% VCM and for longer than 9 weeks from cements containing 5% VCM. The rate of release of VCM differed between cements with different crystallinities as well as between the two dissolution media, PBS and simulated body fluid. Mean concentration of VCM in the bone marrow tissue released from cements containing 5% VCM was 20 times the minimum inhibitory concentration 3 weeks after implantation in bone. Direct contact with new bone was observed with the cements containing 1% VCM. Slow delivery of VCM from a self-setting TTCP-DCPD apatite cement with low crystallinity could be used to treat MRSA osteomyelitis.

Animals↗
PubMed1996

Nasal biopsy in the early diagnosis of Wegener's (pathergic) granulomatosis. Significance of palisading granuloma and leukocytoclastic vasculitis.

The diagnostic value of the nasal biopsy in the early diagnosis of Wegener's granulomatosis and its value in prognosis were examined in 11 patients with a clinicopathological diagnosis of the disease. The vascular lesions found included microabscess in the vascular walls in 82%, leukocytoclastic capillaritis in 73%, fibrinoid necrosis of blood vessels in 45%, leukocytoclastic endovasculitis in 27%, and palisading granuloma in vascular wall in 9% of cases. The extravascular lesions included palisading granuloma in all cases, microabscess in 91%, and diffuse granulomatous tissues in 82%. Palisading microgranuloma (82%) was more frequent than palisading macrogranuloma (45%). After therapy, complete remission occurred in 8 patients, but 3 patients died of sepsis, diffuse pulmonary haemorrhage, and cerebral haemorrhage. Comparison of the frequency of each finding in the nasal biopsy specimens between patients who achieved remission and those who died showed that leukocytoclastic vasculitis was found more commonly in fatal cases, and leukocytoclastic endovasculitis was observed only in fatal cases. Palisading granuloma as a vascular or extravascular lesion is the primary and most important finding in a histopathological diagnosis of Wegener's granulomatosis, microabscess in vascular walls is a secondary but the next most important finding, and leukocytoclastic vasculitis heralds dissemination of the disease and poor prognosis. It requires aggressive therapy.

Adult↗