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Biomedical subjects

H Onishi

Publications and source records attributed to H Onishi.

At least 163 records · Page 9Linked to original sources
PubMed1990

[Fundamental evaluation of bone densitometry using dual energy X-ray absorptiometry (DEXA)].

A newly developed instrument based on dual energy X-ray absorptiometry (DEXA), Hologic QDR-1000, was evaluated fundamentally and clinically. Image quality was quite satisfactory though radiation exposure was minimal, 780.2 nC/kg (3.024 mR) for lumbar measurement. Reproducibility of the repeated measurement of a phantom was fairly good; 0.343 CV% in a same day and 0.520 CV% in a long period. Accuracy determined by measurement of potassium phosphate solution was also satisfactory. Bone mineral densities measured by this instrument were fairly correlated with those measured by single energy quantitative CT; coefficient was 0.740 for 17 patients. Mix-DP plates of more than 10 cm thick overestimated the bone mineral densities of a phantom. Bone mineral densities of Japanese normal volunteers were in the normal range (mean +/- 2SD) of the Americans though mostly lower than the mean. In patients with spondylosis deformans or prominent aortic calcification, bone mineral densities might be overestimated. Lateral view was obtainable though its reproducibility was not good. Positioning especially for measuring femoral neck was quite critical for reproducible measurement. In conclusion, this new instrument is quite accurate and satisfactory for clinical application to measuring bone mineral densities.

Absorptiometry, Photon↗
PubMed1990

Developmental and regional alteration of methionine enkephalin-like immunoreactivity in seizure-susceptible E1 mouse brain.

Methionine enkephalin-like immunoreactivity (ME-LI) in the brain of El mice (seizure-susceptible strain) was measured by radioimmunoassay (RIA) to elucidate the relation between seizures and the opioid system. The lyophilized supernatants of tissue extracts were subjected to ME RIA. The concentration of ME-LI in 25-day-old El mice that had no seizures was significantly decreased in the hippocampus. At the age of 50 days when El mice displayed abortive seizures, the levels of ME-LI in both El(+) and nonstimulated El(o) mice were also significantly reduced in the hippocampus and septal area. It was further shown that the ME-LI concentrations in both 150-day-old adult El(+) during interictal periods and El(o) mice were markedly decreased in the cerebral cortex, septal area, and striatum, as compared with the corresponding regions in ddY mice (seizure-nonsusceptible strain; the mother strain of El). The decrease of ME-LI in the El mouse brain was generally compatible with our previous findings concerning the up-regulation of opioid delta receptors in this species. These results suggest that the reduction of ME-LI in the El mouse brain is not due to convulsions, but could be associated with the pathogenesis of seizure diathesis and seizure manifestations in the El mouse.

Animals↗
PubMed1990

Visualization of the bone/bone marrow of lower extremities in Ga-67 whole-body images.

Patients whose Ga-67 whole-body images showed increased uptake by the bone/bone marrow of the lower extremities were selected and classified into three types according to the extent and the grade of the visualization. These types were then compared with their serum iron levels, iron-binding capacities, and the results of several other serum biochemical tests. Of 374 consecutive whole body 72-hr images reviewed, 59 (15.8%) showed increased uptake of the tracer by the bone/bone marrow of the lower extremities. The three classified types were as follows: type T--visualization of both tibiae and femurs; type S--strong visualization of the femurs; and type W--weak visualization of the femurs. The serum iron concentration was significantly high in type T and low in type S. In conclusion, the pattern of Ga-67 uptake by the bone/bone marrow of the lower extremities fairly closely reflects the status of iron metabolism.

Adolescent↗
PubMed1990

Antitumor characteristics of the conjugate of N4-(4-carboxybutyryl)-ara-C with ethylenediamine-introduced dextran and its resistance to cytidine deaminase.

By oxidation of dextran, and reduction of the Schiff bases formed by reaction of the oxidised dextran with diaminoalkanes, several diaminoalkane-introduced dextrans were prepared and evaluated as drug carriers. Conjugates between N4-(4-carboxyburyryl)-1-beta-D-arabinofuranosylcytosine (glu-ara-C) and such drug carriers were prepared, and selected conjugates were tested in vivo, and investigated for inhibitory effects on cytidine deaminase. Ethylenediamine-introduced dextran prepared under 10% oxidation conditions was found to be most useful as a drug carrier from its chemical characteristics and toxicity evaluation in BDF1 mice. The conjugate obtained from glu-ara-C and ethylenediamine-introduced dextran 2000 showed high antitumor activity, significant at the relatively low dose of 100 mg equivalent ara-C/kg, in BDF1 mice bearing L1210 leukemia cells. Glu-ara-C and the conjugate were unaffected by cytidine deaminase under conditions in which 1-beta-D-arabinofuranosylcytosine was degraded rapidly to 1-beta-D-arabinofuranosyluracil.

Animals↗
PubMed1989

Evidence for the association between two myosin heads in rigor acto-smooth muscle heavy meromyosin.

The rigor complexes that formed between rabbit skeletal muscle F-actin and chicken gizzard heavy meromyosin (HMM), in which the heavy chains had been cleaved with trypsin into 24K, 50K, and 68K fragments, were examined by using the zero-length chemical cross-linker 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC). Two cross-linked products of approximate Mr 115K and 60K were generated. These products were not obtained by EDC treatment of HMM in the absence of F-actin. The HMM fragments that participated in cross-linking were identified by fluorescent labeling and amino acid composition studies. The 115K peptide was determined to be a covalently cross-linked complex that formed between actin and the COOH-terminal 68K fragment of the HMM heavy chain. Our results are in agreement with a previous study which proposed that the site of cross-linking between HMM and F-actin resides within the COOH-terminal 22K fragment of the myosin subfragment 1 heavy chain [Marianne-Pépin, T., Mornet, D., Bertrand, R., Labbé, J.-P., & Kassab, R. (1985) Biochemistry 24, 3024-3029]. The 60K peptide, however, was not a product of cross-linking between HMM and F-actin. On the basis of its amino acid composition, we concluded that this 60K peptide was a cross-linked dimer of the NH2-terminal 24K fragments of the HMM heavy chain. The cross-linking of acto-gizzard HMM significantly increased the Mg-ATPase activity of gizzard HMM without any observable phosphorylation of the regulatory (20K) light chains.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1989

Carbodiimide-catalyzed cross-linking sites in the heads of gizzard heavy meromyosin attached to F-actin.

In the rigor complex between rabbit skeletal muscle F-actin and chicken gizzard heavy meromyosin (HMM), the direct contact between two HMM heads was demonstrated by using a zero-length cross-linker 1-ethyl-3-[3-(dimethylamino)propyl]maleimide (EDC) [Onishi, H., Maita, T., Matsuda, G., & Fujiwara, K. (1989) Biochemistry (preceding paper in this issue)]. Here, the 60K peptide which was a product of the EDC cross-linking between two 24K heavy chain (tryptic) fragments of HMM was further fragmented with cyanogen bromide, and the location of the cross-linking sites on the amino acid sequence of the HMM heavy chain was investigated. The result showed that one site resided within the 77-residue peptide region (residues 1-77) on one head of HMM, whereas the other site belonged to the 40-residue peptide region (residues 164-203) on the other head. This finding suggests that the two HMM heads are in contact with each other at different sites. Ultracentrifugal fractionation revealed that the head-to-head cross-linked gizzard HMM could be reversibly released from F-actin in the presence of Mg-ATP. The yield of the head-to-head cross-linking was not significantly changed with the acto-HMM complex between actin/HMM head molar ratios of 1 and 4, and it was very slightly decreased even at a molar ratio of 8, where HMM molecules were attached sparsely to actin filaments.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1989

Alteration of opioid receptors in seizure-susceptible El mouse brain.

The distribution density of opioid receptors in the brain of El mice (seizure-susceptible strain) was examined to determine the relation between seizures and the opioid system. Saturation curves and Scatchard plots of [3H]2-D-alanine-5-D-leucine enkephalin binding revealed that the opioid delta receptor density in adult El mice during interictal periods was significantly increased in the cerebral cortex, hippocampus, and septal area. It was further shown that the concentration of such receptors in 25-day-old El mice that had no seizures was also significantly increased in the hippocampus and septal area, with no changes in apparent affinities, as compared with in the corresponding regions in ddY mice (seizure-nonsusceptible strain; the mother strain of El). Such up-regulation of opioid receptors in the El mouse brain could result from deficits in endogenous opioid peptides, which could be associated with the pathogenesis of seizure diathesis in the El mouse.

Animals↗
PubMed1989

Granuloma caused by oxidized cellulose following craniotomy.

Three cases are reported in which large granulomas developed 13 to 21 months respectively after removal of intracranial meningiomas (2 cases) and after operation for an anterior communicating artery aneurysm. In each of the cases oxidized cellulose had been used and left in place for haemostasis. All of the granulomas acted as space-occupying lesions. They could be removed operatively with good result. All of them consisted of mononuclear phagocytic and multi-nuclear giant cells and contained remnants of oxidized cellulose. No comparable cases have been reported in the literature. Diagnosis, treatment and possible aetiological factors are discussed.

Adult↗
PubMed1989

Production of leukotriene B4 in parenchymal and sinusoidal cells of the liver in rats treated simultaneously with D-galactosamine and endotoxin.

A study was conducted to investigate production rate of leukotriene B4 (LTB4) in parenchymal and sinusoidal liver cells of rats with acute hepatic failure (AHF). AHF was induced by simultaneous administration of D-galactosamine (GalN) and endotoxin (LPS), and parenchymal as well as sinusoidal liver cells were isolated by collagenase perfusion method. Following preincubation for 15 min, isolated cellular fractions were incubated with Ca-ionophore (2 microM) for 5 min, and levels of LTB4 in culture media before and 5 min after addition of Ca-ionophore were analyzed by HPLC. Following results were obtained: The production rate of LTB4 was found to be the highest in Kupffer cells (7.2ng/10(6) cells/5 min), followed by endothelial cells (1.1), stellate cells (0.2) and parenchymal cells (not detectable). The production rate of LTB4 in both Kupffer cells and endothelial cells was found to reach a maximum in the fraction isolated 60 min after administration of GalN and LPS. Treatment with AA861, one of the selective inhibitors of 5-lipoxygenase, was shown to reduce the production of LTB4 in Kupffer cells to 53% at 10(-7)M and above 99% at higher than 10(-5)M. In conclusion, the majority of LTB4 generated in the liver of rats with AHF was found to be synthesized in Kupffer cells and, to a lesser extent, in endothelial cells, and the enhanced production of LTB4 was found to be greatly inhibited by treatment with AA861.

Acute Disease↗
PubMed1989

Intracranial mycotic aneurysm associated with transsphenoidal surgery to the pituitary adenoma.

A case is reported in which a mycotic aneurysm of the supraclinoidal portion of the internal carotid artery formed as the result of suprasellar infection following transsphenoidal surgery. The source of infection was thought to be a maxillary sinusitis. The aneurysm was treated with systemic antibiotic therapy and disappeared 4 months after the operation. Repeated angiography showed the whole course from the formation to the disappearance of the aneurysm and was valuable in the treatment of intracranial mycotic aneurysms.

Adenoma↗
PubMed1989

Alterations in polyadenylic acid-containing messenger RNA synthesis of brain polysomes after seizures of seizure-susceptible E1 mice.

The effect of seizures on synthesis of the polyadenylic acid (poly(A]-containing messenger RNA (mRNA) isolated from brain polysomes in a genetically seizure-susceptible E1 mouse was studied in vivo. The seizure in the E1 mice was induced by tossed-up stimulation. Immediately after the seizure ceased, the labeled orotic acid was injected into the brain. The incorporation rates of labeled orotic acid into poly(A)-containing mRNA isolated from polysomes are represented as the specific radioactivity (SR) (dpm/mg RNA) and the relative specific radioactivity (RSR) (dpm/mg RNA/dpm/mumoles of acid soluble uridine-5'-monophosphate (UMP]. Both the rates were reduced to 70% in SR and 65% in RSR at 1 h after the seizures. This reduction was gradually recovered to the level of interictal E1 mice at 6 h. The seizure-induced alterations are not attributable to the difference in the uridine nucleotide pool because the SR of UMP was not significantly affected by the seizure. The peak of labeled poly(A)-containing mRNA by analysis of gel electrophoresis displaced towards a lower molecular weight at 1 h after the seizures. The RNA showed a higher ratio of AMP and UMP per GMP and CMP in nucleotide composition, implying that this RNA is identical with DNA. These results suggest that the temporary decrease found in cytoplasmic mRNA synthesis induced by the seizures of E1 mice appears to be a result of impaired transcriptional processes in heterogeneous nuclear RNA synthesis and that the smaller mRNA coding for protein associated with seizures is newly synthesized during the postictal period.

Animals↗
PubMed1989

In vitro pH-dependent drug release from N4-(4-carboxybutyryl)-1-beta-D-arabinofuranosylcytosine and its conjugate with poly-L-lysine or decylenediamine-dextran T70.

N4-(4-Carboxybutyryl)-1-beta-D-arabinofuranosylcytosine (glu-ara-C), the conjugate of glu-ara-C and poly-L-lysine (PLL), (PLL-glu-ara-C), and the conjugate of glu-ara-C and decylenediamine-dextran T70 (T70-C10), (T70-C10-glu-ara-C), were prepared. Drug regeneration from glu-ara-C and the conjugates was investigated in buffered solutions of pH 4,5,7,7.4 and 8. The character of the drug release from the conjugates was different from that from glu-ara-C. Namely, the release of 1-beta-D-arabinofuranosylcytosine (ara-C) from glu-ara-C was accelerated under both weakly acidic and weakly basic conditions, while it was accelerated only under weakly basic conditions from the conjugates. Overall, the drug release profiles from the conjugates showed similar patterns. However, under neutral and weakly basic conditions, ara-C was regenerated more rapidly from PLL-glu-ara-C than from T70-C10-glu-ara-C. During the incubation of glu-ara-C and the conjugates under weakly acidic conditions, 1-beta-D-arabinofuranosyluracil (ara-U) was detected and its amount increased with time to similar extents.

Chemistry, Pharmaceutical↗
PubMed1989

[Cerebral artery occlusion due to blunt cervical trauma].

Three cases are reported in which cerebral infarction developed due to blunt cervical trauma. All of these patients had external signs of cervical trauma and presented focal cerebral ischemic symptoms. Cerebral angiography demonstrated characteristic findings in each case. The first case: A 27 year-old man developed left hemiparesis four days after hitting his neck against a bed rail. Cerebral angiography showed complete occlusion of the right extracranial internal carotid artery 1.5 cm distal to its origin and emboli in distal branches of the right middle cerebral artery. He was treated conservatively. The second case: A 32 year-old man developed disturbance of consciousness with motor aphasia and right hemiparesis a few hours after hitting his chest and neck against baggage hanging from a crane. Cerebral angiography showed complete occlusion of the left middle cerebral artery and no abnormalities of the left internal carotid artery. He was treated with STA-MCA anastomosis two weeks after the accident. The third case: An 84 year-old man, who failed in a suicidal hanging, was semicomatose on admission and had right hemiparesis. Computed tomography demonstrated massive cerebral infarction of the territory of both anterior and left middle cerebral arteries. Cerebral angiography showed linear shadow defect of the left extracranial internal carotid artery corresponding with the site of the ligature. He was treated conservatively. From these angiographic findings, it was thought that intimal tear, intramural hematoma, vasospasm of the internal carotid artery and emboli given might bring about cerebral infarction. In such cases of blunt cervical trauma, cerebral angiography should be undertaken as soon as possible if focal cerebral ischemic symptoms can be seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Magnetic resonance imaging of acoustic neuroma].

Thirteen patients with acoustic neuroma were studied on a 1.5 T superconductive magnetic resonance (MR) imager. Acoustic neuromas appeared as lower signal intensity than the surrounding brain stem on T1 weighted image (W.I.), and as higher signal intensity on T2 W.I.. Axial and coronal sections of T1 W.I. were very useful in observing the tumor in the auditory canal and in investigating the anatomical relations of the tumor and the surrounding structures. MR imaging is very excellent examination to make early diagnosis of the acoustic neuroma and preoperative anatomical evaluation.

Adult↗