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Biomedical subjects

M Hamada

Publications and source records attributed to M Hamada.

At least 307 records · Page 17Linked to original sources
PubMed1993

Production of nerve growth factor by cultured vascular smooth muscle cells from spontaneously hypertensive and Wistar-Kyoto rats.

OBJECTIVE: Nerve growth factor (NGF) is a neurotrophic protein which acts on peripheral sympathetic nerves. Elevated NGF in vascular tissues of young spontaneously hypertensive rats (SHR) has been reported. The aim of the present study was to compare the amount of NGF secreted from cultured vascular smooth muscle cells (VSMC) and mesenteric artery and thoracic aorta segments from SHR and Wistar-Kyoto (WKY) rats. METHODS: VSMC prepared by the enzyme digestion method from the thoracic aortic media of 14-week-old SHR and age-matched WKY rats were subcultured in Dulbecco's modified Eagle's medium containing 10% fetal calf serum. Segments of mesenteric artery and thoracic aorta from 4-week-old SHR and age-matched WKY rats were similarly cultured. The NGF content in conditioned medium was measured using an enzyme immunoassay. The protein content of VSMC was measured by the Lowry method. RESULTS: Total NGF content in the cell culture medium was increased during an exponential growth phase and then gradually decreased during a quiescent phase in both rat strains. There were no significant differences in the levels of NGF secreted from mesenteric artery and thoracic aorta segments between the SHR and WKY rats. The differences in cellular protein content between SHR and WKY rats were very small. CONCLUSIONS: In contrast to the reports of increased NGF in SHR tissues, our data demonstrate that NGF secretion was lower in VSMC from SHR, and was equivalent in mesenteric artery and thoracic aorta segments from SHR and WKY rats. We have no clear explanation for these observations, but the present results indicate that upregulation of NGF in SHR tissues is not responsible for a simple enhancement of NGF synthesis in VSMC, and suggest a breakdown of the regulatory mechanism or mechanisms of NGF gene expression in SHR tissues.

Animals↗
PubMed1993

Neoadjuvant chemotherapy using a platinum, vincristine and peplomycin (CVP) combination in patients with carcinoma of the uterine cervix.

Neoadjuvant chemotherapy consisting of a cis-platinum, vincristine and peplomycin (CVP) combination has been used to treat patients with carcinoma of the uterine cervix at our departments since 1983. Twenty-one patients are reviewed in this study. A high response rate (71.4%) was obtained with 19.0% complete and 52.4% partial responses prior to radical therapy. Survival times and the progression free interval for stage I and III disease treated with CVP show improvement compared to patients not treated with CVP. No life-threatening toxicity related to chemotherapy was noted. This combination chemotherapy used in neoadjuvant setting warrants further study.

Adult↗
PubMed1993

Measurement of cardiac chamber volumes by cine magnetic resonance imaging.

Cardiac chamber volumes (both atria and ventricles) in 19 healthy volunteers were measured noninvasively by cine magnetic resonance imaging (MRI). First, cardiac localization was determined from the coronal image by 0.5-T superconducting magnetic imager. Then, transaxial ECG gated multislice spin echo images were obtained from the bottom to the top of the heart. In the last step, cine MRI was performed at each level of all these transaxial spin echo MR images involving the heart. Each cardiac chamber volume at the same phase was calculated by adding chamber areas in each anatomic section multiplied by slice thickness. Left ventricular (LV) end-diastolic volume (EDV) 132.0 +/- 26.9 mL) and LV end-systolic volume (ESV) (47.8 +/- 13.9 mL) were smaller than right ventricular (RV) EDV (141.1 +/- 24.8 mL) and RVESV (57.0 +/- 12.6 mL), respectively (p < 0.01). LV stroke volume (84.3 +/- 17.9 mL) was equivalent to RV stroke volume (84.2 +/- 17.6 mL) (r = 0.91, p < 0.01). Left atrial (LA) and right atrial (RA) maximal volumes were 75.8 +/- 15.4 mL and 84.4 +/- 18.7 mL, respectively. LA minimal volume (37.5 +/- 10.7 mL) was smaller than RA minimal volume (47.8 +/- 12.2 mL). These values measured by cine MRI are satisfactory and cine MRI will be a useful method of determining cardiac chamber volumes, especially atrial volumes.

Adult↗
PubMed1993

Coronary artery ectasia--a case report and literature review.

A case report of coronary artery ectasia is presented. A middle-aged man was admitted with sudden onset of respiratory arrest which is a rather rare occurrence. Relevant articles are reviewed, and discussion mainly concerns the etiologic and pathophysiologic point of view.

Coronary Artery Disease↗
PubMed1993

Acetylcholine-induced myocardial ischemia without epicardial coronary artery spasm: a possible vasospasm of small coronary arteries--a case report.

Small-vessel vasospasm has been speculated upon as a possible cause of chest pain in patients with normal-appearing coronary angiograms. In this report, a patient who experienced typical chest pain during acetylcholine testing, which caused ST segment elevation without epicardial coronary spasm, is presented. This finding suggests that small-vessel vasospasm may be involved in the induction of myocardial ischemia in patients with normal epicardial coronary arteries.

Acetylcholine↗
PubMed1993

Atrial natriuretic peptide and left atrial systolic function in normal subjects.

The purpose of this study is to elucidate factors determining the release of atrial natriuretic peptide (ANP) in normal volunteers at rest. Ten normal volunteers were included in this study. Ages ranged between twenty-seven and thirty-three years (mean twenty-seven). The authors measured plasma levels of ANP, and four cardiac chamber volumes, and their functions by cine magnetic resonance imaging using the rephased gradient-echo method. Plasma levels of ANP in 10 normal subjects were 15.0-37.1 pg/mL (mean 23.6 pg/mL). No significant relationship was seen between ANP level and heart rate or blood pressure. The level of ANP was positively correlated with left atrial (LA) emptying fraction and negatively correlated with LA minimal volume (r = 0.85, P < 0.01; r = 0.64, P < 0.05, respectively). No significant relationship was observed between plasma ANP level and left ventricular, right ventricular, or right atrial parameters. These results suggest that LA systolic function is one of the major determinants for ANP release in normal subjects at rest.

Adult↗
PubMed1993

Precise assessment of myocardial damage associated with secondary cardiomyopathies by use of Gd-DTPA-enhanced magnetic resonance imaging.

To evaluate the myocardial damage in patients with secondary cardiomyopathies, the authors examined gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) in 5 patients (2 with cardiac amyloidosis, 2 with acute myocarditis, 1 with cardiac thyrotoxicosis). MR images were performed at 1.5-T by using a spin echo pulse sequence before and after intravenous administration of Gd-DTPA (0.2 mmol/kg). All patients revealed distinct high-intensity areas on postcontrast images. Moreover, MRI with Gd-DTPA could determine the severity and precise regions of myocardial damage associated with secondary cardiomyopathies. It is suggested that gated cardiac MRI with Gd-DTPA enhancement is useful for detecting the myocardial damage in secondary cardiomyopathies.

Acute Disease↗
PubMed1993

Effects of glyceryl trinitrate on blood pressure and arterial compliance.

Glyceryl trinitrate (GTN) mainly reduces systolic blood pressure (SBP) rather than diastolic blood pressure (DBP) in acute conditions. To examine the efficacy of GTN as an antihypertensive agent in patients with isolated systolic hypertension (ISH), the authors examined the effects of GTN on BP and arterial compliance (AC) in patients who underwent cardiac catheterization. Seventy patients (with old myocardial infarction, 36; angina pectoris, 25; chest pain syndrome, 9) who underwent cardiac catheterization because of chest pain were included in this study. They were aged between thirty-seven and seventy-four (mean sixty-one) years. According to the levels of BP at cardiac catheterization, the authors selected two subgroups: the normotensive group (NT group, n = 18) and the isolated systolic hypertensive group (ISH group, n = 20) from all subjects. The authors measured BP before and after (three minutes) sublingual administration of GTN (0.3 mg) at the cardiac catheterization. AC was assessed by means of diastolic pressure decay. The change of BP was estimated by the differences between values before and at three minutes after GTN. After administration of GTN, SBP was decreased significantly from 157 +/- 25 to 142 +/- 23 mmHg (P < 0.01), while DBP did not change (83 +/- 13 vs 84 +/- 15 mmHg). The change in SBP was positively correlated with the pretreatment SBP and negatively correlated with AC (r = 0.51, P < 0.001; r = 0.39, P < 0.001, respectively). AC was significantly lower in the ISH group than in the NT group (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

The amino acid sequence of neocarzinostatin apoprotein deduced from the base sequence of the gene.

A segment of the neocarzinostatin apoprotein gene corresponding to T30 to A91 of the protein was amplified using a polymerase chain reaction (PCR) with total DNA from Streptomyces carzinostaticus subsp. neocarzinostaticus E-793 (ATCC 15944) as the template and with 5'- and 3'-primers synthesized in consideration of the codon usage of streptomyces. The PCR product was cloned, sequenced and confirmed to direct an amino acid sequence reasonably well matching that reported. Using the PCR product as a probe, we cloned a DNA segment (2580 bp) spanning an open reading frame (ORF) for preapoprotein (leader peptide plus apoprotein) and its upstream and downstream flanking regions. The amino acid sequence deduced from the base sequence of the DNA clearly identified those amino acid residues which had remained inconsistent among different research groups. The base sequence homology with other apoprotein genes of related antibiotics was analyzed and was found to be limited within the structural gene.

Amino Acid Sequence↗
PubMed1993

Morphological characteristics of hypertrophic cardiomyopathy estimated by left ventriculography.

To determine the common morphological characteristics of hypertrophic cardiomyopathy (HCM) by ventriculography from a right anterior oblique projection, diaphragmatic and free wall configurations were analyzed in 15 patients with obstructive HCM (HOCM), 32 patients with nonobstructive HCM (HNCM) and 17 controls. There was a convexity extending into the left ventricle in the right anterior oblique projection due to hypertrophy of the interventricular septum (IVS) in all patients with HCM. The peak convexity, where septal thickness was maximal (M point), was closer to the base in HOCM than in HNCM. Due to this convexity, the left ventricle showed a catenoid-shaped distortion at the M point. The distortion was severer in HOCM than in HNCM. Left ventricular free wall (LVFW) thickness was measured at the base and near the apex. LVFW thickness in HOCM decreased toward the apex, similar to that in controls, but in 17 of 32 HNCM (53%) LVFW thickness increased toward the apex. Cardiac index and stroke index in HCM were significantly smaller than those in controls. There was a significant correlation between the position of the M point and stroke index in HCM. These results indicate that a common morphological characteristic of HCM on the diaphragmatic side is the existence of a convexity extending into the left ventricle, and that cardiac performance in HCM is greatly influenced by the nature of the convexity. Myocardial abnormality seems to exist primarily at the base of the IVS in HOCM, and primarily in the lower part of the IVS and LVFW in HNCM.

Adult↗
PubMed1993

Aortic valvular disease and right coronary artery stenosis induced by mediastinal irradiation--report of a case.

This report presents a case of aortic valvular dysfunction and right coronary artery disease following radiation therapy on the mediastinum. A 61-year-old woman had received mediastinal radiation for the treatment of right mammary cancer 20 years previously. She developed symptoms of congestive heart failure 6 months ago. The patient was found to have aortic valvular dysfunction and proximal stenosis of the right coronary artery. Surgical aortic valve replacement improved cardiac status, and vasodilator treatment reduced ischemia due to right coronary artery stenosis.

Aortic Valve↗
PubMed1993

Localization of Cu/Zn and Mn superoxide dismutase in various thyroid disorders.

The intracellular localization of Cu/Zn- and Mn-superoxide dismutase (SOD), which catalyze the dismutation of superoxide radicals (O2-) to O2 and H2O2, was studied in the thyroid tissue of various thyroid disorders by an immunohistochemical technique. The concentrations of both SODs in those tissues were measured also by a sandwich enzyme immunoassay technique. Copper/zinc-SOD in thyroid tissues were identified by immunocytochemical staining in most cases of papillary carcinoma and in some cases of other thyroid disorders. In normal follicular cells this enzyme is localized in the perinuclear cytoplasm, whereas in thyroid tumor or hyperplastic follicular cells it exists homogeneously in cytoplasm. Manganese-SOD stained strongly in papillary carcinoma and papillary-growing cells in the thyroid tissue of adenoma and Graves' disease. The concentrations of Cu/Zn-and Mn-SOD in thyroid tumor tissues and hyperplastic follicular disorders were significantly higher than those in normal thyroid tissue when they were compared as a function of protein or deoxyribonucleic acid contents. The ratio of Mn-SOD to Cu/Zn-SOD was significantly higher only in papillary carcinoma, except for other thyroid disorders as compared with that in the normal thyroid. In conclusion, SOD seems to be related to cell proliferation and differentiation in the thyroid follicular cell because Cu/Zn-SOD changes its localization in tumor and hyperplastic follicular cells and because the Mn-SOD concentration is increased in papillary carcinoma or papillary-growing cells.

Humans↗
PubMed1993

An adult case with multiple cardiac valve prolapse and regurgitation.

A 56-year-old female had pure regurgitation in all cardiac valves. Color Doppler echocardiography showed a regurgitant jet in all cardiac valves. The severity of regurgitation due to the prolapse in all valves was moderate. The patient had no history of rheumatic fever, ischemic heart disease, endocarditis or hypertension. Physical characteristics of the patient were neither of Marfan's nor Ehlers-Danlos' syndrome. The etiology of regurgitation in all cardiac valves of this patient may be due to multiple valve prolapse.

Aortic Valve Insufficiency↗
PubMed1993

Hepatitis in an adult with rubella.

Rubella was accompanied by hepatic dysfunction in a 28-year-old male. Serum aminotransferase levels were moderately elevated and LDH markedly increased, especially LDH isoenzyme 5, whereas total bilirubin and ALP remained almost normal. GOT, GPT and LDH levels were completely normalized by the 21st hospital day. Paired antibody titers of viruses which may cause hepatitis, other than rubella, were of no significance. Laparoscopy showed enlarged, red liver. Histologic and electron microscopic findings of the liver were consistent with acute hepatitis. Hepatic damage with rubella is rare, and it is possible that the hepatic dysfunction seen in adult rubella may be mediated by an immunopathologic mechanism.

Acute Disease↗
PubMed1993

Effects of casein and soy protein on accumulation of cholesterol and dolichol in rat liver.

A diet containing 15% (w/w) fat and 20% (w/w) of either casein (CAS) or soy protein (SOY) was fed to 4-week-old rats for a period of 18 months. The effects of these dietary proteins on the accumulation of cholesterol and dolichol in livers were studied. After 1 month, the amount of liver cholesterol was about 5 mg/g of liver. After an additional 5 months of feeding, there was a slight decrease in cholesterol per gram of liver (3.6 mg/g of liver in CAS-fed rats and 2.6 mg/g of liver in SOY-fed rats). However, after 18 months, there were a remarkable increase (7.5 mg/g of liver) in CAS-fed rats and only a slight increase in SOY-fed rats. The proportions of liver cholesterol ester in rats fed the CAS diet were 60-70% of the total cholesterol during the experimental period, but in the case of the SOY diet, only rats fed the diet for 1 month showed a high level, 70%, of cholesterol ester. The amounts of liver dolichol in rats fed the CAS and SOY diets after feeding for 18 months were 60 micrograms and 47 micrograms of liver, respectively. There was a 1.5-fold increase in both diets for a period of 18 months. The proportions of liver dolichyl fatty ester in rats fed the CAS diet were 35-40% of the total dolichol during the experimental period, but in the case of the SOY diet, only rats fed the diet for 1 month showed a high level, 36%, of dolichyl fatty ester. The proportions of dolichol ester in rats fed the SOY diet were 25-30% after 6 and 18 months of feeding. These observations indicated that the SOY diet depresses the accumulation of both liver dolichol and cholesterol.

Animals↗
PubMed1993

Delaminomycins, novel extracellular matrix receptor antagonist. IV. Structure-activity relationships of delaminomycins and derivatives.

Delaminomycins A, B, C and their derivatives were prepared and investigated biological activities of them. Among these compounds, spiro compounds (A2, B2 and C2) showed stronger inhibitory activity than natural products (A1, B1 and C1) on B16 melanoma cells adhesion assay and Con A-induced proliferation of murine splenic lymphocytes assay. In MLCR and antimicrobial assay, however, A1, B1 and C1 showed more potent inhibitory activity than spiro compounds (A2, B2 and C2). On the other hand, as to C-5' substituents of pyrrolidine ring, the order of inhibitory activity was R = OH > R = OCH3 > R = H on Con A-induced proliferation of murine splenic lymphocytes assay. In MLCR and antimicrobial assay, however, the order of inhibitory activities were R = H > R = OCH3 > R = OH. Inhibitory activities of A4 which was lacked pyrrolidine ring were reduced on B16 melanoma cells adhesion assay and on cytotoxicity against tumor cells in vitro in comparison with those of A1.

Animals↗
PubMed1993

Dephostatin, a novel protein tyrosine phosphatase inhibitor produced by Streptomyces. I. Taxonomy, isolation, and characterization.

A novel inhibitor of protein tyrosine phosphatase, dephostatin, was isolated from the culture broth of a strain of Streptomyces. The active principle was extracted from the broth filtrate with ethyl acetate and purified by silica gel chromatography and by HPLC. Dephostatin inhibited protein tyrosine phosphatase prepared from a human neoplastic T-cell line with an IC50 at 7.7 microM. The inhibitory pattern of dephostatin was competitive against the substrate. Dephostatin inhibited the growth of Jurkat cells.

Cell Division↗