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Biomedical subjects

S Umezawa

Publications and source records attributed to S Umezawa.

At least 55 records · Page 3Linked to original sources
PubMed1991

Synthesis of 3'-deoxy-3'-fluorokanamycin A and 3',4'-dideoxy-3'-fluorokanamycin A.

3'-Deoxy-3'-fluorokanamycin A (14) has been prepared by condensation of 6-azido-2,4-di-O-benzyl-3,6-dideoxy-3-fluoro-alpha-D-glucopyranlsyl++ + bromide (8) and 6-O-(2-O-acetyl-4,6-O-cyclohexylidene-3-deoxy- 3-tosylamino-alpha-D-glucopyranosyl)-2-deoxy-1,3-di-N-tosylstre ptamine (10). Compound 8 was obtained from 3-deoxy-3-fluoro-1,2:5,6-di-O-isopropylidene-D-glucofuranose in seven steps. 3',4'-Dideoxy-3'-fluorokanamycin A (22) has been prepared from 12 through selective 4'-chlorodeoxygenation, a key reaction. Both 14 and 22 were more active than 3'-deoxykanamycin A against both sensitive and resistant bacteria.

Anti-Bacterial Agents↗
PubMed1991

[Effects of antianginal drugs on left ventricular diastolic filling in patients with ischemic heart disease].

To study the acute effects of isosorbide dinitrate (ISDN), nifedipine, propranolol and placebo on left ventricular diastolic filling in patients with myocardial ischemia, we repetitively performed exercise radionuclide angiography (RNA) following random assignment of each drug in 12 patients with effort angina pectoris, and 5 normal controls. Left ventricular time activity curves were constructed using computer technique. We obtained changes of hemodynamic parameters such as endodiastolic volume, systemic vascular resistance and ejection fraction. The peak filling rate (PFR), and filling rate in the first third of the diastolic period (1/3 FR) were used as the indexes of LV diastolic filling. 1/3 FR remained unchanged during peak exercise by the patients, while it increased significantly in normal controls. After administration of ISDN and nifedipine, 1/3 FR increased significantly during peak exercise by the patients. Especially after nifedipine, 1/3 FR improved significantly compared with the improvement after ISDN, although these two drugs had the same effects on systolic function. These findings showed that 1/3 FR was reliable as an indicator of LV diastolic filling in ischemic heart disease, and nifedipine improved LV diastolic filling not only by improving ischemic changes in myocardium but also by it's direct effect on left ventricular relaxation.

Aged↗
PubMed1990

Change in the growth hormone (GH) response to GH-releasing factor (GRF) caused by exogenous GH in short children.

To determine whether exogenous GH induces feedback of GH release in children, growth hormone-releasing factor (GRP) tests were performed before and after 10-day GH administration. Sixteen non-obese short boys, aged 5-14 yr, with normal GH response to pharmacological tests were studied. Mean basal and peak serum GH levels in GRF tests before and after exogenous GH were not significantly different. The subjects were divided into two groups, A and B, according to the percent change in integrated areas under the GH curves in GRF tests (GH AUC) before and after 10-day GH administration. Group A consisted of 6 boys with decreased GH AUC and group B consisted of 10 boys with increased GH AUC. Mean peak GH in GRF tests and mean GH AUC were significantly higher before exogenous GH in group A than in group B. The boys in group A were all prepubertal, while 4 boys in group B had begun their early pubertal change. The mean age in group A (7.8 +/- 1.8 yr) was significantly lower than that of group B (11.9 +/- 2.4 yr). GH AUC before exogenous GH showed a significant correlation with the percent change in AUC (= -0.742, p less than 0.01). These data demonstrated that the exogenous GH suppressed the GH response to GRF in prepubertal children with good response to GRF before exogenous GH, while it exaggerated the GH response to GRF in older children with relatively poor response before GH.

Adolescent↗
PubMed1990

[Effect of verapamil on myocardial infarct size estimated by serial 201-thallium single-photon emission tomography].

To investigate the effects of intravenous verapamil (V) in coronary thrombolytic therapy, we serially observed the time course of perfusion of the myocardium by 201-thallium (Tl) SPECT in patients who were successfully reperfused within 6 hours from the onset. 201-Tl SPECT was attempted serially on the 1st-2nd day, the 7th-10th day and 28th-30th day. In addition to this, we calculated the count ratio of radioactivity of 99mTc-PYP (CR) in the infarcted myocardium to sternum to evaluate intracellular uptake of calcium during reperfusion. The infarct size, estimated by % Defect decreased significantly in the patients treated with V, while it remained unchanged in the patients without it. In the patients with V, the left ventricular ejection fraction was more favourable, and exercise-induced ischemia determined by redistribution of 201-Tl SPECT in the chronic phase was found more frequently. CR showed no difference between reperfused myocardium irrespective of the treatment. In conclusion, verapamil was considered to enhance myocardial salvage carried out by reperfusion, and not to affect the influx of intracellular calcium into the injured myocytes.

Drug Evaluation↗
PubMed1989

[Urinary hGH, albumin, alpha 1 MG and beta 2 MG in normal and diabetic children].

I measured urinary hGH level in children with insulin dependent diabetes mellitus (DM) and studied the relation with urinary albumin alpha 1-microglobulin (alpha 1 MG), beta 2-microglobulin (beta 2MG) and plasma HbA1. 24-hour urine or night-time urine was collected in 54 normal children (NC) and 61 DM. Urinary hGH was estimated by using a sensitive sandwich enzyme immunoassay. Urinary albumin, alpha 1 MG and beta 2MG were measured by RIA. HGH concentration in 24-hour urine in NC significantly correlated with urinary albumin and beta 2MG concentrations (p less than 0.01). In DM, hGH concentration in 24-hour urine also correlated with urinary albumin concentration (p less than 0.05). To avoid the effects of posture and exercise, night-time urine was used in the following study. Urinary hGH concentration was significantly higher in DM for all age (p less than 0.05-0.01) than that in NC. Urinary alpha 1MG and beta 2MG concentrations were also significantly higher in DM than those in NC. HGH concentration in night-time urine in NC has not correlated with urinary albumin, alpha 1MG nor beta 2MG. In DM, however hGH significantly correlated with urinary albumin and beta 2MG. Even in DM with normal concentrations of urinary albumin and beta 2MG, urinary hGH was significantly higher than in NC. Urinary hGH in poorly controlled DM was higher than in well controlled DM. Urinary hGH concentration showed positive correlation with plasma HbA1 in DM. We conclude that urinary hGH relates to not only serum hGH concentration but also renal function. In DM with normal renal function, hGH concentration in night-time urine was higher than in NC, which suggested high serum hGH concentration in DM.

Adolescent↗
PubMed1989

A large myxoma of the right atrium demonstrated by thallium-201.

A rare case of right atrial myxoma in which thallium-201 gave a good delineation of the tumor was presented. In this case, the feeding arteries were seen to be highly developed on coronary arteriogram. The amount of blood containing thallium-201 supplied to the tumor through the feeding arteries was so great that the tumor was considered to be visualized by thallium-201 imaging.

Aged↗
PubMed1989

Heterogeneity of big-big hPRL in hyperprolactinemia.

Sera from a patient with macroprolactinoma (case 1) and from a hyperprolactinemic woman with regular menstruation (case 2) were analyzed for prolactin activity by gel filtration using Sephadex G-100, Sephadex G-200 and TSK G3000SW columns. The chromatographic profile by Sephadex G-100 showed that the percentage of immunoreactive big-big hPRL was 10.7% in case 1 and 64.1% in case 2. On Sephadex G-200 and TSK G3000SW columns, the molecular weight of big-big hPRL was estimated to be more than 500,000 daltons (big-big1 hPRL) in case 1 and approximately 250,000-300,000 daltons (big-big2 hPRL) in case 2. Big-big1 hPRL in case 1 was converted to big and little hPRLs when the serum was treated with 2-mercaptoethanol (2-ME), but part of the big-big2 hPRL in case 2 was converted to a larger molecule. Radioactive big-big hPRL generated by mixing labeled hPRL with the serum from case 1 was eluted with the void volume on Sephadex G-100 column and was not converted to the other molecular forms after 2-ME treatment. There were two radioactive big-big hPRL on TSK G3000SW column and these estimated molecular weights were more than 300,000 daltons. The data demonstrated the existence of at least two forms of big-big hPRL in the serum and indicated that radioactive big-big hPRL may be different from these hPRLs in the serum.

Chromatography, Gas↗
PubMed1989

Bioactivity of human growth hormone in urine from acromegalic patients.

Bioactivity of hGH in urine from five acromegalic patients was determined by Nb2 bioassay and IM-9 receptor modulation assay (RMA). Urine samples were concentrated by immunoadsorbent chromatography, dialysis and lyophilization. The ratio of the bioactivity by Im-9 RMA and the immunoactivity by RIA was between 0.81 and 1.24 (1.01 +/- 0.19, mean +/- SD). The ratio of the bioactivity by Nb2 bioassay and the immunoactivity ranged from 0.45 to 0.60 (1.37 +/- 0.85). Gel chromatography of hGH in urine samples measured by sensitive sandwich enzyme immunoassay showed that more than 97% of hGH activity was the 22K form. Urinary hGH from acromegalic patients was bioactive in Nb2 bioassay and IM-9 RMA and the bioactivity showed a close correlation with the immunoactivity. The major immunoactive form of hGH (22K) seems to correspond to the bioactivity.

Acromegaly↗
PubMed1989

Biological activities of synthesized 20K and 22K hGH in Nb2 bioassay and IM-9 radioreceptor assay.

We investigated the bioactivities of the recombinant DNA-derived methionyl 20K hGH (20K-Met-hGH) and methionyl hGH (22K-Met-hGH). The growth-promoting activities in Nb2 cells of 20K-Met-hGH and 22K-Met-hGH were 10.7% and 93.5% of pituitary hGH (P-hGH), respectively. In the IM-9 lymphocyte assay, the binding activities of 20K-Met-hGH and 22K-Met-hGH to hGH receptor were 29.0% and 87.1% of P-hGH, respectively. Our data demonstrate that 20K-Met-hGH may have weaker biological potency than P-hGH.

Animals↗
PubMed1989

[Clinical significance of the technetium-99m/thallium-201 overlap in acute myocardial infarction].

The region of overlap of thallium-201 (Tl) and technetium-99m pyrophosphate (Tc) was evaluated as a scintigraphic prognosticator of future necrosis. Serial time courses of myocardial perfusion according to Tl and left ventricular wall motion evaluated by two-dimensional echocardiography (2D echo) were used in 22 patients. In all, dual energy emission computed tomography (dual-SPECT) showed the Tl/Tc overlap on identical slices on the third post-infarction day. According to the results of dual-SPECT, the patients were categorized in three groups: nine with large Tl/Tc overlap (group A); five with small Tc accumulation and small Tl/Tc overlap (group B); and eight with large Tl defect and Tc accumulation, which are concordant with each other (group C). Tl-201 SPECT and 2D echo were attempted serially on the 1st and 2nd days, the 7th-10th days and the 28th-30th days. To estimate infarct size with Tl-201 SPECT, we measured pixel counts of eight short-axis images with the 40% cut-off level and computed "% defect". To evaluate the viability of the myocardium, "% Tl uptake" was computed from the ROIs both in the centers of the infarct areas and their border zones. 2D echoes of the left ventricular short axis at the chordae tendineae level were recorded to identify the time course of percent fractional area change (% FAC) of the ischemic left ventricular wall. The scintigraphic results were compared with the serial changes of regional ejection fraction in the areas of infarcts and ischemic lesions. The % defect remained unchanged in group C (29.2 +/- 11.5----25.7 +/- 8.3%); whereas those of groups A and B decreased significantly (21.2 +/- 11.3----9.9 +/- 6.3%, 13.8 +/- 2.6----5.4 +/- 2.9%, respectively). In groups A and B, % FAC improved significantly in the centers of the infarct areas and the border zones, but not in group C. Exercise-induced ischemia determined by redistribution of Tl at the chronic phase was observed more frequently in groups A and B than in group C. These findings indicated that more myocardium can be saved from necrosis in group A than in group C. In conclusion, it is suggested that there is considerable viable myocardium in patients with large Tl/Tc overlap on dual-SPECT.

Aged↗
PubMed1989

[Dobutamine stress thallium myocardial scintigraphy compared with two-dimensional echocardiography].

To assess the relationships among wall motion abnormality, myocardial ischemia and ST change in patients with myocardial infarction (MI), dobutamine stress thallium (Tl) myocardial scintigraphy, and two-dimensional echocardiography (2DE) and electrocardiography were simultaneously performed. Sixteen patients with anterior MI who underwent 2DE and ECG were studied at baseline and during dobutamine infusion with incremental doses of two to 40 micrograms/kg/min. The stress endpoints were chest pain, significant ST changes, tachycardia (greater than or equal to 110/min), and complicated arrhythmias. At the maximal tolerable dose of dobutamine, Tl scintigraphy was completed, and then repeated again four hours later. Left ventricular wall motion was evaluated using superimposed wall tracings of the configuration on 2DE, and was expressed as regional % area changes. Myocardial ischemia was quantified by SPECT and measured as regional % Tl uptake. Dobutamine stress testing was well tolerated by all patients, and no complications occurred. Hemodynamic changes included: heart rate increased from 61 +/- 9 to 113 +/- 11 beats/min, left ventricular end-diastolic volume (2DE) decreased from 93 +/- 27 to 59 +/- 33 ml, and mean blood pressure and ejection fraction were unchanged. In 11 of the 16 patients, redistributions on planar and SPECT images were observed. Although redistributions were observed in the areas adjacent to infarcts in patients with significant ST elevation in V3, additional wall motion abnormalities were not observed. The shape of the ST elevation had no relation to myocardial ischemia. In some cases, wall motion abnormality can be improved in spite of ischemia. Thus, this new combined method is useful for evaluating the relationship between ischemia and wall motion dynamics.

Adult↗
PubMed1988

[Bioactivity and heterogeneity of human growth hormone in urine from acromegalic patients].

Bioactivity of hGH in urine from five acromegalic patients was determined by Nb2 rat lymphoma bioassay (Nb2BA) and IM-9 receptor modulation assay (RMA). One urine sample (case 1) was concentrated by dialysis and lyophilization. Bioactivity by IM-9 RMA showed close correlations with immunoactivity by RIA in serial dilutions (RMA/RIA; 0.66-1.77). The estimates of bioactivity by Nb2BA were higher in all diluted samples except undiluted one than those of immunoactivity. Four samples were concentrated by affinity chromatography, dialysis and lyophilization. The ratio of RMA and RIA estimates was between 0.81-1.24, and that of Nb2BA and RIA estimates was between 0.46-2.62. Heterogeneity of urinary hGH was analyzed by gelfiltration using TSK-G-3000SW column by high performance liquid chromatography (HPLC) and by sensitive sandwich enzyme immunoassay. In addition to the main peak of 22K molecular weight (more than 97%), very small peaks of 40-60K (big hGH) and 150K (big-big hGH) were detected in chromatographic profile. Urinary hGH from acromegalic patients was bioactive in IM-9 RMA and Nb2BA. The predominant form of urinary hGH from acromegalic patients was little hGH, but big and big-big hGH were detected by sensitive sandwich enzyme immunoassay.

Acromegaly↗
PubMed1988

The effects of antianginal drugs on left ventricular function in patients with effort angina pectoris. Comparison among isosorbide dinitrate, nifedipine and propranolol by PANOVA.

To study the acute effects of ISDN, nifedipine, propranolol and placebo on cardiac function in patients with myocardial ischemia and to characterize their hemodynamic effects by PANOVA, we repetitively performed exercise radionuclide angiography (RNA) following random assignment of each drug in 20 patients with effort angina pectoris. We obtained exercise response curves of hemodynamic parameters determined by RNA. ANOVA was performed to analyze the sizes (average height) of those response curves, and PANOVA (principal component analysis, PCA, combined with ANOVA) to analyze differences in the profiles (patterns) of the curves. By conventional analysis of variance followed by a Scheffé type multiple comparison, end-diastolic volume after ISDN, which was significantly smaller than those after the other drugs at rest (p less than 0.01), was similar to those after nifedipine and propranolol during exercise (96.4 +/- 4.6 ml/m2 vs. 94.8 +/- 5.1 ml/m2 and 97.1 +/- 4.9 ml/m2, respectively). Systemic vascular resistance after nifedipine, which was also significantly lower than those after the other drugs at rest (p less than 0.05), was not different from that after placebo during exercise (16.9 +/- 1.1 units vs. 18.7 +/- 1.3 units). Thus, this analysis was considered insufficient to fully differentiate the characteristics of each drug. By PANOVA, the profiles of LVEF with these three antianginal drugs were similar, and significantly differentiated from that of placebo (p less than 0.05). This indicated that the antianginal effect could be represented by the profiles of the response curves of LVEF, using PANOVA. Evaluating the underlying hemodynamic mechanisms of these drugs by PANOVA, ISDN was significantly differentiated from nifedipine and propranolol by the profile of end-diastolic volume (p less than 0.05). The characteristics of nifedipine were clearly demonstrated by the size and profile of systemic vascular resistance, and those of propranolol were also differentiated by the size and profile of the double product and P-V index. Hence, it is concluded that with the aid of PANOVA, the changes in hemodynamic parameters during ischemia can be evaluated in a manner that is highly effective in differentiating the characteristics of the effects of antianginal drugs in patients with angina pectoris.

Aged↗