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Biomedical subjects

M Hamada

Publications and source records attributed to M Hamada.

At least 505 records · Page 28Linked to original sources
PubMed1987

[Myocardial ischemia with negative stress electrocardiography: evaluation by stress RI studies].

Patients with negative stress electrocardiography (ECG) (no ST segment depression) were re-evaluated by means of stress RI studies including 201T1 single photon emission computed tomography (SPECT) and 99mTc-RBCs radionuclide ventriculography (RNV). Four hundred seven patients, including 303 with old myocardial infarction (OMI; SPECT: 188, RNV: 115) and 104 with effort angina (EA; SPECT: 58, RNV: 46), all of whom underwent left ventriculography and coronary arteriography, were re-evaluated by symptom-limited graded bicycle ergometer exercise RI testing. The results were as follows: 1. Among those with negative stress ECG (53% of OMI and 31% of EA), 54% and 73% of OMI and EA, respectively, had positive SPECT. 2. Among those with negative stress ECG (56% of OMI and 39% of EA), 70% and 39% of OMI and EA, respectively, had positive delta EF (poor increase in ejection fraction: delta EF less than 5%) and, 41% and 28% of OMI and EA had deteriorated regional wall motion. 3. Those with OMI and negative ECG showed no correlations with the numbers of diseased vessels, infarcted sites, or ischemic areas. In conclusion, RI testing appears to be a significantly more sensitive means of detecting stress-induced ischemia, compared to stress ECG.

Adult↗
PubMed1987

Etiologic factors of myelopathy. A radiographic evaluation of the aging changes in the cervical spine.

The radiographic characteristics of the cervical spine among older individuals were investigated in 100 normal subjects and compared with those of younger subjects. The cervical spine of the older subjects displayed narrowing of intervertebral discs and osteophytoses (posterior osteophytes as well as anterior osteophytes) at the levels of C5-6 and C6-7, where the range of motion was decreased. Such degenerative changes resulted in vertebrolisthesis, especially retrolisthesis, predominantly at the levels of C3-4 and C4-5, where intervertebral disc space was well maintained and mobility was well preserved. Both static and dynamic anteroposterior canal diameter decreased with age. Throughout the aging process the dynamic canal became much narrower than the static canal, except at C2-3. Posterior osteophytes at C5-6 or C6-7 and retrolisthesis at C3-4 or C4-5 were major levels of stenosis associated with changes in the dynamic canal. Following the same evaluation system, 20 elderly patients with cervical spondylotic myelopathy were assessed. Based on the above-noted characteristics of the aging process, patients with myelopathy had smaller static and dynamic canal measurements than normal subjects. The development of cervical myelopathy, however, was not always based on critical static or dynamic canal stenosis (10% in this series) and might involve other factors.

Aged↗
PubMed1986

Ca2+,Mg2+-ATPase of microsomal membranes from bovine aortic smooth muscle: effects of Sr2+ and Cd2+ on Ca2+ uptake and formation of the phosphorylated intermediate of the Ca2+,Mg2+-ATPase.

The effects of various divalent cations on the Ca2+ uptake by microsomes from bovine aortic smooth muscle were studied. High concentrations (1 mM) of Co2+, Zn2+, Mn2+, Fe2+, and Ni2+ inhibited neither the Ca2+ uptake by the microsomes nor the formation of the phosphorylated intermediate (E approximately P) of the Ca2+,Mg2+-ATPase of the microsomes. The cadmium ion, however, inhibited both the Ca2+ uptake and the E approximately P formation by the microsomes. Dixon plot analysis indicated Cd2+ inhibited (Ki = 135 microM) the Ca2+ dependent E approximately P formation in a non-competitive manner. The inhibitory effect of Cd2+ was lessened by cysteine or dithiothreitol. The strontium ion inhibited the Ca2+ uptake competitively, while the E approximately P formation increased on the addition of Sr2+ at low Ca2+ concentrations. At a low Ca2+ concentration (1 microM), Sr2+ was taken up by the aortic microsomes in the presence of 1 mM ATP. It is thus suggested that Sr2+ replaces Ca2+ at the Ca2+ binding site on the ATPase.

Animals↗
PubMed1986

Clinical significance of early diastolic time intervals for the evaluation of left ventricular function in patients with coronary artery disease.

To investigate non-invasively the diagnostic significance of diastolic properties in coronary artery disease (CAD), the following early diastolic time intervals (EDTIs): IIA-O time (from the aortic component of the second heart sound to the O-point on the apexcardiogram), IIA-MVO time (from IIA to the mitral valve opening) and MVO-O time (from MVO to the O-point), were estimated in 18 patients with angina pectoris (AP) and 29 with old myocardial infarction (OMI) who were subdivided into two groups according to ejection fraction (EF): group I (OMI-I): more than 50% and group II (OMI-II): less than 50%. Seventeen patients without evidence of CAD were used as controls (N). Left ventricular pressure (LVP) and pulmonary capillary wedge pressure (PCWP) were measured simultaneously to clarify the relationship between EDTIs and early diastolic hemodynamics. IIA-O time and IIA-MVO time in AP, OMI-I and OMI-II were significantly longer than in N. This prolongation accorded with the reduction of left ventricular function. MVO-O time in AP and OMI-I also was significantly longer compared with that in N. In OMI-II, however, it was significantly shorter than in N. The prolongation of IIA-MVO time reflected impaired LV relaxation accompanied by LV dysfunction. The maintenance of low minimal LVP was the main contributor to the lengthening of MVO-O time in AP and OMI-I. Conversely, elevated minimal LVP and impaired LV relaxation resulted in the shortening of MVO-O time in OMI-II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Isolation and properties of valanimycin, a new azoxy antibiotic.

Valanimycin, a new azoxy antibiotic, was isolated from culture broths of a streptomycete. Valanimycin is an unstable oil at room temperature and active against some Gram-positive and Gram-negative bacteria, mouse leukemia L1210 cells in cultures, and prolongs the life span of mice inoculated with Ehrlich carcinoma or L1210.

Animals↗
PubMed1986

Novel antibiotics napyradiomycins. Production, isolation, physico-chemical properties and biological activity.

Novel antibacterial antibiotics napyradiomycins A, B1, B2, B3, C1 and C2 have been isolated from the culture broth of Chainia rubra MG802-AF1. In this paper, taxonomy of the producer, and production, isolation, physico-chemical properties and biological activities of napyradiomycins are reported. They contain the naphtopyran chromophore and halogens, and inhibit the growth of Gram-positive bacteria including drug-resistant strains.

Animals↗
PubMed1986

Plipastatins: new inhibitors of phospholipase A2, produced by Bacillus cereus BMG302-fF67. I. Taxonomy, production, isolation and preliminary characterization.

Plipastatins have been isolated as part of a program designed to find inhibitors of porcine pancreatic phospholipase A2. They were purified from fermentation broth of Bacillus cereus BMG302-fF67 and finally separated into four fractions by reverse phase HPLC. The respective fractions were designated as plipastatins A1, A2, B1 and B2. Plipastatins also inhibited phospholipases C and D.

Animals↗