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Biomedical subjects

K Harada

Publications and source records attributed to K Harada.

At least 523 records · Page 29Linked to original sources
PubMed1996

[A case of Aicardi syndrome: neurophysiological investigation].

A Japanese girl developed tonic spasms in series at two months after birth. When she was admitted at 4 months, she had generalized muscle hypotonia and could not control her head. She had atotal agenesis of the corpus callosum on MRI, reticulo-lacunitis revealed by ophthalmologic examination, and hypsarrhythmia in EEG. Brain stem auditory evoked potentials and flash-visual evoked potentials exhibited abnormally asymmetrical findings. The cortical components of somatosensory evoked potentials were not elicited on admission, but some components became to be recognized on median nerve stimulation in accordance with improvement of EEG findings after various therapeutic trials. We concluded that these neurophysiological examinations were useful to investigate the abnormal lesions of the central nervous system in patients with Aicardi syndrome.

Agenesis of Corpus Callosum↗
PubMed1996

Intervention of crescentic glomerulonephritis by antibodies to monocyte chemotactic and activating factor (MCAF/MCP-1).

We investigated the pathophysiological role of a potent macrophage (M(phi)) chemotactic cytokine (chemokine), monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 (MCAF/MCP-1), in an animal model of crescentic glomerulonephritis. Administration of a small dose of nephrotoxic sera induced severe proliferative and necrotizing glomerulonephritis, with crescentic formation in the early phase and glomerulosclerosis in the later phase, in Wistar-Kyoto rats. MCAF/MCP-1 protein was detected immunohistochemically in glomeruli, vascular endothelial cells, and tubular epithelial cells in the early phase of injured kidney tissues but not in normal ones. Anti-MCAF/MCP-1 antibodies decreased the number of M(phi) in glomeruli, and prevented crescentic formation and the fusion of epithelial cell foot process in nephritic rats, thereby decreasing the excreted amounts of protein to normal levels on days 3 and 6. Furthermore, anti-MCAF/MCP-1 antibodies remarkably reduced glomerulosclerosis and improved renal dysfunction as well as proteinuria in the later phase (56 days). These results indicate that MCAF/MCP-1 essentially participates in the impairment of renal functions associated with crescentic glomerulonephritis by recruiting and activating M(phi).

Animals↗
PubMed1996

Mesenchymal chondrosarcoma in anterior skull base: case report.

We report the case of a 16-year-old boy who presented with mesenchymal chondrosarcoma involving the ethmoid sinus, right orbit, nasal cavity, and anterior cranial fossa. The tumor was totally resected by craniofacial surgery; the patient's postoperative course was uneventful. Microscopically, the tumor was composed of highly cellular undifferentiated small cells, alternating with zones of cartilaginous tissues. Mesenchymal chondrosarcoma is a rare, aggressive variant of chondrosarcoma, which might be encountered more frequently due to the advances in neuroimaging and surgical procedures.

Adolescent↗
PubMed1996

[Blood flow measurement of portal vein with fast cine phase contrast MR imaging under breath-holding].

Flow measurements of the right portal vein were performed in seven healthy volunteers with the segmented k-space fast gradient-echo phase-contrast (fcard-PC) sequence under breath-holding. The mean velocity and the flow rate of the right portal vein at maximal expiration, 14.3 +/- 4.4cm/sec and 457 +/- 218 ml/min, were significantly greater (p < 0.01) than those at maximal inspiration: 11.8 +/- 3.8cm/sec (mean +/- SD) and 364 +/- 191ml/min, respectively. Fcard-PC enabled flow measurements to be obtained under breath-holding. Using this technique, we demonstrated portal venous flow changes according to respiratory phase.

Adult↗
PubMed1995

Identification of two novel arginine binding DNAs.

RNA tertiary structure is known to play critical roles in RNA-protein recognition and RNA function. To examine how DNA tertiary structure might relate to RNA structure, we performed in vitro selection experiments to identify single-stranded DNAs that specifically bind arginine, and compared the results with analogous experiments performed with RNA. In the case of RNA, a motif related to the arginine binding site in human immunodeficiency virus TAR RNA was commonly found, whereas in the case of DNA, two novel motifs and no TAR-like structures were found. One DNA motif, found in approximately 40% of the cloned sequences, forms of hairpin structure with a highly conserved 10 nucleotide loop, whereas the second motif is especially rich in G residues. Chemical interference and mutagenesis experiments identified nucleotides in both motifs that form specific arginine binding sites, and dimethylsulfate footprinting experiments identified single guanine residues in both that are protected from methylation in the presence of arginine, suggesting possible sites of arginine contact or conformational changes in the DNAs. Circular dichroism experiments indicated that both DNAs undergo conformational changes upon arginine binding and that the arginine guanidinium group alone is responsible for binding. A model for the G-rich motif is proposed in which mixed guanine and adenine quartets may form a novel DNA structure. Arginine binding DNAs and RNAs should provide useful model systems for studying nucleic acid tertiary structure.

Arginine↗
PubMed1995

Cloning and structural analysis of the mouse apolipoprotein B mRNA editing protein gene.

Mouse apolipoprotein B mRNA editing protein gene has been isolated and characterized. The amino acid sequences deduced from the exonic sequences of the gene showed 90, 70 and 68% identity to those of rat, human and rabbit, respectively. RNA blotting experiments demonstrated high expression in small intestine especially in the jejunum as a major 2.4 kb mRNA species. mRNA in other tissues including the liver is smaller in amounts and larger in size (3.1 kb) than the intestinal mRNA. The gene spans 12 kb and contains 5 exons and 4 introns. Sequencing of the 5'-flanking region revealed that a canonical TATA box is absent and the consensus recognition sequences for several transcription factors have been identified.

APOBEC-1 Deaminase↗
PubMed1995

Role of age on transmitral flow velocity patterns in assessing left ventricular diastolic function in normal infants and children.

This study demonstrated that both peak E and flow velocity integral of early diastole increased to reach the older children's values by 36 months of age and leveled off thereafter, whereas both peak A and flow velocity integral of atrial contraction had little change. These results suggest that age-related changes in E wave reflect the maturational or developmental alterations in LV diastolic properties, especially in the relaxation process.

Adolescent↗
PubMed1995

Overexpression of human lipoprotein lipase increases hormone-sensitive lipase activity in adipose tissue of mice.

An elevation of lipoprotein lipase (LPL) activity in adipose tissue is considered a possible cause of obesity. However, transgenic mice that overexpress the human LPL gene showed no increase in fat deposition as compared with controls. In the present study, we investigated effects of LPL on fat accumulation. Respiratory quotients and uptake of [3H] triolein by tissues (white and brown adipose tissue, and skeletal muscles) did not differ significantly for transgenic and non-transgenic mice. The mRNA levels of hormone-sensitive lipase (HSL) and HSL activity in adipose tissue during feeding were higher in LPL transgenic mice than in controls. Results suggest that the overexpression of LPL does not induce obesity by enhancing the hydrolysis of triglycerides in adipose tissue.

Adipose Tissue↗
PubMed1995

Characteristics of antitumor activity of 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]- 2(1H)-quinolinone (vesnarinone) against a human adenoid squamous carcinoma-forming cell line grown in athymic nude mice.

The tumors produced by transplantation into nude mice of human adenoid squamous carcinoma-forming cell line TYS, presumably derived from a minor salivary gland, were treated with a differentiation-inducing agent, vesnarinone, which was given per o.s. daily at a dose of 200 mg/kg for 35 days. They were then examined morphologically and immunohistochemically. The vesnarinone treatment resulted in a significant suppression of tumor growth. In addition, tumor nests indicating keratinocyte and acinar cell differentiation were often observed in the treated tumors, but not in untreated controls. Tissue sections from vesnarinone-treated and untreated TYS tumors were stained with monoclonal antibody (NAb) directed to carbohydrate antigen LeY or proliferating cell nuclear antigen (PCNA) and with rabbit polyclonal antibody to p53. Antibody staining patterns were compared with morphological characteristics of cells as revealed by hematoxylin and eosin staining, and DNA fragmentation patterns as revealed by 3'-OH nick-end labelling techniques. Tissue sections from vesnarinone-treated TYS tumors showed positive reaction with nick-end labelling and were extensively stained strongly by anti-LeY MAb, whereas the untreated tumors showed negative reaction with nick-end labelling and were infrequently stained by anti-LeY MAb. Within LeY-positive areas of tissue sections from the vesnarinone-treated tumors, keratinocyte and acinar cell differentiation as well as DNA fragmentation were frequently observed, although not all LeY-positive cells showed such signs of apoptosis. LeY-positive cells showed consistent negative staining by anti-PCNA MAb and anti-p53 rabbit serum. From these findings, it can be considered that vesnarinone has differentiation and apoptosis-inducing activity against TYS cells grown in athymic nude mouse.

Animals↗
PubMed1995

A Comparison of Mass Screening for Breast Cancer Using Mammography and Physical Examination Alone in Japan.

To compare the sensivity of breast cancer screening methods by conventional physical examination and film mammography, a trial of mass screening for breast cancer using mammography was principally carried out in asymptomatic women over 50 years of age in Tokushima Prefecture. In this trial craniocaudal and mediolateral oblique imagings of the breast using two-view film mammography and physical examination, using inspection and palpation of the breasts were performed independently. Breast cancer was detected in 8 of a total of 950 examinees by mammography alone, and no cases of breast cancer were detected by physical examination. The detection rate of breast cancer was 0.84%, that is 7 times higher than that(0.12%) obtained by conventional mass screening using physical examination alone. The detection rate of increased especially in the sixth and seventh decades of life. The stage of the detected breast cancer was stage 0 (Tis) in 5 cases and stage T, with a tumor size of 1.0 cm or less, in 3 cases. All 8 cases were in the early stage, and they underwent breast conservation therapy. Based on these results, it is recommended to employ mammography in breast cancer screening for asymptomatic women aged over 50 years. We consider mammography alone may be sufficient for mass screening for breast cancer in these subjects.

Journal Article↗
PubMed1995

Structure determination of galacto-oligosaccharides by pyridylamination and NMR spectroscopy.

Galacto-oligosaccharides formed from lactose by the action of some beta-galactosidases were subjected to gel chromatography on Bio-Gel P-2, and the resulting oligosaccharide fractions were converted into pyridylamino (PA) derivatives. Each PA-oligosaccharide fraction, which consisted of several isomers in a given size-class, was then subjected to HPLC on an ODS column. Twenty-one individual galacto-oligosaccharide components were isolated in this way. The structures of most of these compounds, namely six disaccharides, five trisaccharides, two tetrasaccharides, and a pentasaccharide, were determined by 13C-NMR spectroscopy. The results obtained will be useful for the study of the activity of various galacto-oligosaccharides on the growth of Bifidobacterium species.

Aminopyridines↗
PubMed1995

Cardiac arrest after traffic accident induced through vagal reflex in a case with bilateral stenosis of vertebral arteries.

An 84-year-old driver suffered cardiac arrest after a traffic accident. He was quickly resuscitated and transferred to a hospital where he was treated in a state of unconsciousness and respiratory failure for 20 days until his death. The brain stem was rendered anoxic during cardiac arrest, which caused the respiratory failure. Artificial ventilation and catecholamine infusion were carried out, resulting in myocardial degeneration. Bilateral stenosis of the vertebral arteries was disclosed, but no injuries or hemorrhage of the brain and spinal cord were detected. On days 3 and 4 after admission, immediately after the head of the victim was flexed forward for examinations, cardiac arrest was induced twice, but was controlled either by administering atropine or by restoring the original posture. Positional change is known to induce vagal reflex that results in bradycardia, hypotension or cardiac arrest in sensitive persons. The victim might have undergone the reflex-mediated cardiac arrest after the accident, to which the stenosis of the vertebral arteries may have contributed.

Accidents, Traffic↗
PubMed1995

Differentiation between dysmyelination and demyelination using magnetic resonance diffusional anisotropy.

Using magnetic resonance (MR) diffusion-weighted method, we examined the optic and the trigeminal nerves of jimpy and twitcher mice, considered to be animal models of Pelizaeus-Merzbacher disease, hypomyelination disorder, and Krabbe disease, demyelination disorder, respectively. In jimpy mice, diffusional anisotropy of optic nerve did not show a significant difference compared to age-matched control mice, suggesting that diffusional anisotropy does exist in absence of multiple layers of myelin sheath. In twitcher mice, diffusional anisotropy was attenuated remarkably in the optic and trigeminal nerves. Loss of axonal straightness on longitudinal section confirmed by electron microscopy appeared to be the principal explanation for it. It is further suggested that this MR diffusion-weighted imaging method enables us to differentiate hypomyelination from demyelination in vivo.

Animals↗
PubMed1995

Role of macrophage colony-stimulating factor in the initial process of atherosclerosis.

The early atherosclerotic lesion is characterized by the presence of macrophage-derived foam cells. Macrophage colony-stimulating factor (M-CSF) specifically stimulates the functions of the monocyte-macrophages. To elucidate the role of M-CSF in the atherogenic process in vitro and in vivo, we studied the effects of M-CSF on enzyme activities of acidic cholesteryl ester (CE) hydrolase, neutral CE hydrolase, and acyl-coenzyme A:cholesterol acyltransferase (ACAT), and 300 micrograms of M-CSF was intravenously injected into WHHL rabbits aged 2.5 months for 8.5 months. M-CSF (100 ng/ml) enhanced acidic and neutral CE hydrolase, and ACAT activities by 3.2-fold, 4-fold, and 2.3-fold, respectively, in the presence of acetyl LDL, and M-CSF increased ratios of both acidic and neutral CE hydrolase activities to ACAT activity. After M-CSF injection into WHHL rabbits, we found very retarded progression of atherosclerosis. The accumulation of cholesterol ester was remarkably decreased in the aortae of M-CSF-treated animals (0.60 +/- 0.32 mg/g tissue), as compared to those of controls (4.21 +/- 0.65 mg/g tissue). The results suggest that M-CSF prevents the progression of atherosclerosis in WHHL rabbits by increasing net hydrolysis of cholesteryl ester in macrophages.

Animals↗