Search PubMed⌕ Search

Biomedical subjects

K Harada

Publications and source records attributed to K Harada.

At least 289 records · Page 16Linked to original sources
PubMed1999

Translocation of HSP27 and MKBP in ischemic heart.

HSP27 and MKBP translocate from the cytosolic to myofibril fraction in ischemic rat heart as demonstrated by immunoblotting. Immunohistochemistry analysis showed that ischemia enhances the Z line labeling of HSP27 and MKBP. Two dimensional gel electrophoresis showed that ischemia increases the hyperphosphorylated form of HSP27. These data suggest that HSP27 and MKBP may be involved in the Z line protection against postischemic reperfusion injury.

Actins↗
PubMed1999

A comparison of the antagonistic activities of tamsulosin and terazosin against human vascular alpha1-adrenoceptors.

Tamsulosin, a selective alpha1A-adrenoceptor antagonist, and terazosin, a non-selective one, are effective for the treatment of urinary disturbance due to benign prostatic hypertrophy. In the present study, their alpha1-adrenoceptor-blocking effects on blood vessels, which may cause orthostatic hypotension, were investigated in 10 healthy males. After the subjects took orally 0.2 mg of tamsulosin, 1 mg of terazosin or a lactate capsule as the control in a randomized cross-over fashion, their finger tip vasoconstrictor response to cold stimulation and vasoconstrictor response of the dorsal hand vein to increasing doses of phenylephrine were examined. The finger tip vasoconstrictor response was significantly reduced and the infusion rate of phenylephrine producing a half-maximal constriction was significantly increased by terazosin, but tamsulosin had no significant effect on these parameters. These data suggest that the usual dose of tamsulosin exerts little alpha1-adrenoceptor-blocking activity on blood vessels, and orthostatic episodes might be mild, if any, during the treatment with tamsulosin.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1999

Levothyroxine-induced liver dysfunction in a primary hypothyroid patient.

Here we report a case of levothyroxine-induced liver dysfunction. T4 (levothyroxine) has been more commonly used for the treatment of hypothyroidism than T3 active hormone (triiodothyronine), because with the former drug a stabler plasma concentration is obtained after oral administration. Although there are few reports on levothyroxine-induced liver dysfunction, we treated a primary hypothyroid patient with high serum aminotransferase after administration of levothyroxine. Liver dysfunction was improved after cessation of the drug administration. Antibody to T4 was found in the serum of the patient after this event. From clinical course and laboratory data of the patient, the episode of liver damage was considered to be induced by levothyroxine. We then administrated triiodothyronine, and it did not induce liver dysfunction. Changing levothyroxine to triiodothyronine resulted in a successful clinical course in this case, as re-administration of the doubtful drug is strictly limited.

Adolescent↗
PubMed1999

An adult case with an abnormal right ventricular structure causing intraventricular pressure gradient and a history of aphthous stomatitis and thrombophlebitis.

We report a 50-year-old man with a right ventricular structure causing an intraventricular pressure gradient. He had been diagnosed as vasculo-Behçet with a history of aphthous stomatitis and thrombophlebitis. He had also been suffering from atrial flutter and mild right-side heart failure. Echocardiography showed that there was an abnormal structure attached to the right ventricular free wall and protruding into the cavity, and that it caused the pressure gradient estimated to be approximately 19 mmHg. Chest X-ray computed tomography demonstrated that the structure was partially calcified. Magnetic resonance imaging depicted the structure separating the right ventricle into two chambers. Angiographic study revealed a markedly enlarged right atrium and a filling defect at the mid-portion of the right ventricle, which divided the right ventricular cavity into two parts. Hemodynamic study showed a slightly elevated right atrial pressure (mean 7 mmHg) and a peak-to-peak intraventricular pressure difference of 18 mmHg in the right ventricle. The diastolic pressure tracing of the right ventricular low pressure chamber showed a 'dip and plateau' pattern. Although the pathological features of the abnormal right ventricular structure in this case were not fully clarified, abnormal muscle bundle and/or endocardial fibrosis, which were reported to be associated with Behçet's disease, may have contributed to its generation.

Atrial Flutter↗
PubMed1999

Morphological adaptation of the cardiovascular system in fetal rats during late gestation.

The aim of this study was to evaluate morphological changes of the cardiovascular system in fetal rats during late gestation. We used the rapid whole-body freezing technique for rats of day 17 through 21 of gestation. The right and left ventricular volumes increased markedly and significantly during this period by about 11- and 24-fold, respectively. Although the right ventricular volume was 108% larger with statistical significance than the left ventricular volume on day 17, they were almost equal after day 19. The length of the primum septum of the atrium significantly increased by 92% within 4 days, but the opening distance of foramen ovale significantly decreased by 14%. The ratio of the inner diameter (the sum of right and left pulmonary arteries to ductus arteriosus) significantly increased from 0.72+/-0.03 on day 17 to 1.17+/-0.07 on day 21. There was also a significant increase in the ratio of the inner diameters of the ascending to descending aorta. These observations suggest that the reduction of the opening distance of foramen ovale reflect the growth of pulmonary arteries.

Adaptation, Physiological↗
PubMed1999

Right ventricular diastolic filling assessed by conventional doppler and tissue Doppler imaging in normal children.

To examine age-related changes in right ventricular filling dynamics, we performed conventional pulsed Doppler (n=99) and tissue Doppler (n=30) echocardiographic studies in normal subjects aged 7 days to 273 months. The tricuspid flow velocity during early diastole (peak E) wave correlated significantly but weakly with the logarithm of age. The peak E wave in the early neonatal period was almost 80% of the older children's values and increased to 100% by 36 months of age. In the right ventricular tissue Doppler imaging, the peak myocardial velocity during early diastole also increased significantly with the logarithm of age. However, the tissue Doppler peak A did not change with age. There was a significant correlation between the tissue Doppler peak E wave and the tricuspid peak E wave and between the tissue Doppler peak E/A wave and the tricuspid peak E/A wave. The age-related changes in the tricuspid inflow velocity patterns were similar to the age-related alterations in the right ventricular myocardial velocity patterns. Age-related changes in the tricuspid inflow velocity and myocardial velocity patterns may be related to age-related maturation in the right ventricular diastolic performance.

Adolescent↗
PubMed1999

The relationship between magnetic resonance imaging findings and clinical manifestations of hypothalamic hamartoma.

OBJECT: Hypothalamic hamartoma is generally diagnosed based on its magnetic resonance (MR) imaging characteristics and the patient's clinical symptoms, but the relationship between the neuroradiological findings and clinical presentation has never been fully investigated. In this retrospective study the authors sought to determine this relationship. METHODS: The authors classified 11 cases of hypothalamic hamartoma into two categories based on the MR findings. Seven cases were the "parahypothalamic type," in which the hamartoma is only attached to the floor of the third ventricle or suspended from the floor by a peduncle. Four cases were the "intrahypothalamic type," in which the hamartoma involved or was enveloped by the hypothalamus and the tumor distorted the third ventricle. Six patients with the parahypothalamic type exhibited precocious puberty, which was controlled by a luteinizing hormone-releasing hormone analog, and one patient was asymptomatic. No seizures or mental retardation were observed in this group. All patients with the intrahypothalamic type had medically intractable seizures, and precocious puberty was seen in one. Severe mental retardation and behavioral disorders including aggressiveness were seen in two patients. The seizures were controlled in only one patient, in whom stereotactically targeted irradiation of the lesion was performed. This topology/symptom relationship was reconfirmed in a review of 61 reported cases of hamartoma, in which the MR findings were clearly described. The parahypothalamic type is generally associated with precocious puberty but is unaccompanied by seizures or developmental delay, whereas the intrahypothalamic type is generally associated with seizures. Two thirds of patients with the latter experience developmental delays, and half also exhibit precocious puberty. CONCLUSIONS: Classification of hypothalamic hamartomas into these two categories based on MR findings resulted in a clear correlation between symptoms and the subsequent clinical course.

Adolescent↗
PubMed1999

Damage to DNA purified from the radioresistant prokaryote, Deinococcus radiodurans, by acid heating.

Using a highly radioresistant bacterium, Deinococcus radiodurans, the mechanism of degradation of the purified DNA molecules by heating was examined under acidic conditions. Setting the treatment temperature at 55ûC with a duration of 0 to 20 min and adjusting the pH of the cell suspension to 3, 5 or 7, cell viabilities after the treatment were compared. The survival rate decreased in proportion to the reduction of pH. DNA purified from D. radiodurans was then damaged by irradiation with gamma-rays at 0.22 kGy or 1 kGy. It was considered that the radioresistance of D. radiodurans was due to its high repair capability, rather than any specificity of DNA structure. Purified D. radiodurans DNA was resistant to heating up to 90ûC at neutral pH. However, marked DNA damage occurred when it was heated at pH values below 5.0. Then, DNA labeled with [3H]adenine was examined. Treatment at lower pH and higher temperature resulted in release of more adenine base, i.e., the purine ring, from the DNA molecules. Therefore, we assumed that the decrease in survival of D. radiodurans in vivo and damage to its DNA in vitro by acid heating were due to the release of adenine and guanine from the DNA, i.e., depurination.

Acids↗
PubMed1999

Sensitivity of shuttle vector plasmid pZ189 DNA to carbon ion beams.

The sensitivity of shuttle vector plasmid pZ189 DNA to carbon ion beams was studied under dry conditions. This plasmid contains the supF gene that can be used in mutagenesis analysis. The survival curve of the plasmid had both a shoulder and exponential parts, and showed a D10 value of about 17 kGy for both Escherichia coli wild-type and DNA repair-deficient mutant (UV-sensitive) strains. Therefore, it was assumed that the excision repair system was not effective for repairing DNA lesions induced by irradiation with carbon ion beams.

Carbon↗
PubMed1999

[A case of cerebral juvenile pilocytic astrocytoma: observation of the development of the tumor].

A case with cerebral juvenile pilocytic astrocytoma (JPA) was reported. The patient was 33-month-old boy, who developed headache and loss of activity on December, 1994. Although he was indicated macrocephaly at the age of just 1 year, CT scan showed no abnormality at that time. On admission, MRI revealed multiple large cysts with an enhanced mural nodule in the left frontal lobe. The tumor was totally removed, and histologically diagnosed as JPA, because of alternating two types of structures of loose knit tissue composed of satellite astrocytes and compact tissue consisting of highly fibrillate cells. MIB-1 percent positivity was almost negative. We summarized and discussed the clinicopathological and proliferating characteristics of the cerebral JPA. These considerations suggested that the tumor already existed at the age of 1 year and developed during these 20 months, according to the theory that the growth rate of JPAs is programmed to slow down as the patient grows.

Astrocytoma↗
PubMed1999

Impaired beta-adrenoceptor mediated venodilation in patients with diabetes mellitus.

AIMS: We investigated whether venoconstriction by alpha-adrenoceptor stimulation, and venodilation by beta-adrenoceptor stimulation and nitroglycerin are altered in patients with diabetes mellitus (DM). METHODS: Eight male patients with non insulin-dependent DM and eight age-matched control subjects were included. The patients had neither hypertension nor hyperlipidaemia. Noradrenaline (1 to 512 ng min-1 ), isoprenaline (1 to 256 ng min-1 ) and nitroglycerin (0.5 to 128 ng min-1 ) were infused into a dorsal hand vein and its diameter was measured using a linear variable differential transformer. RESULTS: The venoconstricting response to noradrenaline and the venodilating response to nitroglycerin in DM patients were similar to those in control subjects, while the venodilation by isoprenaline was significantly (P<0.05) smaller in DM patients than in control subjects at the dose of 32 ng min-1 or more [32 ng min-1: 11.5% vs 29.8% (DM vs control subjects), 64 ng min-1: 19.0% vs 40.1%, 128 ng min-1: 25.2% vs 49.0%, 256 ng min-1: 34.3% vs 56.7%]. CONCLUSIONS: These data suggested that venoconstriction by alpha-adrenoceptor stimulation and venodilation by nitroglycerin are not altered, whereas venodilation by beta-adrenoceptor stimulation might be impaired in patients with DM.

Adult↗
PubMed1999

Preliminary investigation of resistance of plasmid DNA to neon ion beams using transformation into recipient Escherichia coli cells.

The sensitivity of the vector plasmid pKmK8 DNA to neon ion beams was studied under dry conditions. This plasmid contains the cloning vector pJKKmf(-) and a 3.6 kbp segment encoding the Escherichia coli crp gene that can be used in mutagenesis analysis. The survival curve of the plasmid indicated an exponential profile and a D10 value of about 16 kGy in the E. coli wild-type strain for DNA repair capability. This was similar to the D10 value for the shuttle vector plasmid pZ189 DNA. Therefore, it was assumed that the excision repair system in E. coli was not effective for repairing DNA lesions induced by irradiation with heavy ion beams.

DNA Damage↗
PubMed1999

Centipede inflicted postmortem injury.

We here report the first case of postmortem injury caused by a centipede. An old man was found dead in his bedroom. The death was estimated to be due to intracranial hemorrhage and to have occurred two days before the police inspection. A centipede about 12 cm long emerged from a subcutaneous cavity on the victim's forearm. Obviously, the centipede had dug the cavity on the intact skin. A police inspector was bitten by the centipede, so he stepped on the centipede on the floor. The exudate from the insect was identified to be derived from the victim's blood.

Aged↗