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Biomedical subjects

J Ito

Publications and source records attributed to J Ito.

At least 235 records · Page 13Linked to original sources
PubMed1990

Diagnostic imaging of maxillofacial lesions with CT and MRI.

Normal anatomy of the maxillofacial regions is clearly shown by both CT and MRI. The use of dental devices causes deterioration in CT and MRI of the tongue and oral floor. A high-resolution bone window display is highly useful in examining bony structures. Contrast CT is useful in diagnosis of tumorous, inflammatory, and vascular lesions. MRI shows the extensions of tumors more clearly than CT, and MRI enhanced with Gd-DTPA is very useful in determining tumor extensions into bony structures. Both CT and MRI should be used in diagnosis of maxillofacial lesions.

Humans↗
PubMed1990

[Experimental study on maturational therapy of osteosarcoma cell].

We investigated the differentiation-inducing effects of dibutyryl cyclic AMP (dBc AMP) on several cultured osteosarcoma cell lines (DUNN, MOLONEY, OST, FBJ). 1. Cell growth rates of all the osteosarcoma cell lines were reduced by 3mM dBc AMP. 2. Both alkaline phosphatase activity and 45Ca2(+)-uptake were promoted by 3mM dBc AMP. 3. There was, in each cell line except for the OST cells, a marked enlargement of the cell processes under the light microscopic observation. At the electron microscopic level, there were also many findings indicating an increase in cell functions. These results suggest that the differentiation may be induced by cAMP in osteosarcoma cells, and that the differentiation therapy by cAMP-related drugs is promising for a clinical application.

Alkaline Phosphatase↗
PubMed1990

[A case of xanthoma of the skull].

The reports in the radiologic literature of osseous xanthoma are very rare. We reported a case of xanthoma of the skull without hyperlipidemia. The bony changes is well-marginated radiolucent lesion with marginal sclerosis and an central nidus of bone.

Bone Diseases↗
PubMed1989

[Effects of anti-platelet aggregating agents on peplomycin induced pulmonary toxicity in mice].

In order to find a method to ameliorate pulmonary toxicity of peplomycin (PEP), microscopic changes of the lung following PEP administration and effect of anti-platelet aggregating agents on the toxicity was investigated in mice. When PEP was administered intravenously once a day for 7 days, microthrombi mainly composed of aggregated platelets and fibrin appeared in the capillaries of the lung in an early phase before severe pulmonary edematous lesions and fibrosis occurred. Combination therapy of anti-platelet aggregating agents such as phthalazinol, dipyridamole, ticlopidine and indomethacin suppressed these toxic changes. Especially, ticlopidine was the most effective and superior to prednisolone used clinically for amelioration of the toxicity. Microthrombi, preceding edematous lesions, were considered to be attributed to damages of endothelium by PEP, because PEP itself did not develop platelet aggregation in vitro and ex vivo. Therefore, the microthrombi are likely to produce congestion of pulmonary microcirculation leading to edematous lesions by increase of permeability, and to play significant roles in the development of pulmonary fibrosis in a late phase. Anti-platelet aggregating agents such as ticlopidine are concluded to ameliorate the lung toxicity by preventing microcirculation impairment with the microthrombus.

Animals↗
PubMed1989

Induction of astroglial growth inhibition and differentiation by sialosyl cholesterol.

Normal rat astroblasts in culture were exposed to 11 sialosyl or cholesterol derivatives at concentrations lower than 20 microM. Synthesized sialosyl cholesterols (alpha- and beta-D-N-acetyl neuraminyl cholesterols) and cholesterol sulfate showed a marked growth inhibitory action. Sialosyl cholesterol uniquely evoked an astroglia-like stellation resembling that induced by glia maturation factor (GMF) as well as a suppression of GMF-induced mitogenesis of astroblasts. The minimal incubation period of sialosyl cholesterol for the initiation of growth inhibition was as short as one hour. The inhibitory effect retained an irreversibility even after removal of the drug. Cytosolic protein with 58 kDa Mr in size was specifically phosphorylated by sialosyl cholesterol through a certain protein kinase dependent on neither Ca2+ nor cyclic AMP. The competition experiment of sialosyl cholesterol action revealed that sialosyl and cholesterol moieties were indispensable for the phenomena. These results most likely imply that sialosyl cholesterol alters the membrane microenvironment to affect the affinity of growth factor receptor, protein kinase activity, and/or cytoskeletal anchorages.

Animals↗
PubMed1989

Topographic study of the feline trigeminal ganglion via the horseradish peroxidase tracer method.

The somatotopic organization of the trigeminal ganglion was investigated in felines using the horseradish peroxidase (HRP) tracer method. Results were as follows. The cell bodies which send axons to the ophthalmic, maxillary and manidibular nerves were located in the anteromedial, middle and posterolateral portions of the ipsilateral trigeminal ganglion, respectively. Overlap was found, especially in the maxillary and mandibular areas.

Animals↗
PubMed1989

The autonomic innervation in the pharynx. A study by the horseradish peroxidase tracer method.

Autonomic innervation of the mucosa in the pharynx was investigated by the horseradish peroxidase retrograde tracer method. The pharynx was divided into three regions, the epipharynx, mesopharynx, and hypopharynx. The epipharynx was sympathetically innervated by the fibers originating in the ipsilateral superior cervical ganglion and parasympathetically innervated by the fibers originating in the bilateral pterygopalatine ganglia. The mesopharynx and hypopharynx were sympathetically innervated by the fibers originating in the superior cervical, middle cervical, and stellate ganglia but not innervated by the pterygopalatine ganglion. The sympathetic innervation of the mesopharynx and hypopharynx was considered bilateral and predominant in the ipsilateral side. Comparing these two regions, the hypopharynx showed a tendency to be more innervated by the middle cervical and stellate ganglia.

Animals↗
PubMed1989

Protein-primed replication of bacteriophage PRD1 genome in vitro.

A cell-free system has been developed from cells of an Escherichia coli strain, carrying cloned genes 1 and 8 of bacteriophage PRD1, that catalyzes protein-primed DNA synthesis. DNA synthesis in vitro is entirely dependent upon the addition of PRD1 DNA-protein complex as template, Mg2+, and four deoxyribonucleoside triphosphates. No in vitro DNA synthesis was observed when deproteinized PRD1 DNA was used as template. The origin and direction of PRD1 DNA replication in vitro was determined by restriction enzyme analysis of 32P-labeled PRD1 DNA synthesized in this system. Replication starts at both ends of the linear PRD1 DNA template. Alkaline sucrose gradient centrifugation and agarose gel electrophoresis showed that full-length PRD1 DNA is synthesized in vitro. DNA synthesis in this system is inhibited by the drug aphidicolin. We also observed that dimethyl sulfoxide (DMSO) stimulates in vitro DNA synthesis, although it inhibits bacterial DNA polymerase.

Aphidicolin↗
PubMed1989

T5 DNA polymerase: structural--functional relationships to other DNA polymerases.

T5 DNA polymerase, a highly processive single-polypeptide enzyme, has been analyzed for its primary structural features. The amino acid sequence of T5 DNA polymerase has a high degree of homology with that of DNA polymerase I from Escherichia coli and retains many of the amino acid residues that have been implicated in the 3'----5' exonuclease and DNA polymerase activities of that enzyme. Alignment with sequences of polymerase I and T7 DNA polymerase was used to identify regions possibly involved in the high processivity of this enzyme. Further, amino acid sequence comparisons of T5 DNA polymerase with a large group of DNA polymerases previously shown to exhibit little similarity to polymerase I indicate certain sequence segments are shared among distantly related DNA polymerases. These shared regions have been implicated in the 3'----5' exonuclease function of polymerase I, which suggests that the proofreading domains of all these enzymes may be evolutionarily related.

Amino Acid Sequence↗
PubMed1989

Enhancement of both intracellular uptake and antitumor action of cisplatinum on human neuroblastoma cells by encapsulation in liposomes.

Phospholipid vesicles (phosphatidylcholine:phosphatidylserine:cholesterol = 6:2:3 in molar ratio) with a small unilamellar structure were used as drug carriers for introducing cis-diamminedichloroplatinum (CDDP) into human neuroblastoma cells, IMR-32, GOTO, Nagai, and TGW. DNA synthesis of IMR-32 cells among the human neuroblastoma cell lines was inhibited most strongly by CDDP-liposomes. CDDP-liposomes dose-dependently inhibited the DNA synthesis of IMR-32 in a similar fashion to that observed with free CDDP, but the drug concentration required to induce 50% inhibition of DNA synthesis for CDDP-liposomes (IC50: 0.7 micrograms CDDP/ml) was 1/3 of the IC50 for free CDDP (2.0 micrograms CDDP/ml). In support of the marked growth-inhibitory action of CDDP-liposomes, the intracellular incorporation rate of CDDP-liposomes was 3-fold higher when liposomes were used as carriers than when free CDDP was directly applied. CDDP-liposomes showed a stronger growth inhibition on IMR-32 cells at a high cell density than at a low density in culture. CDDP-liposomes were rapidly incorporated by IMR-32 cells within 5 min, resulting in the inhibition of DNA synthesis to 40% of the control. Swiss albino mouse 3T3 cells were less inhibited by CDDP-liposomes than by free CDDP, suggesting that encapsulation of CDDP in liposomes decreases cytotoxicity to normal cells.

Biological Transport↗
PubMed1989

High-incidence of C9 deficiency throughout Japan: there are no significant differences in incidence among eight areas of Japan.

From 92,686 sera sent from hospitals throughout Japan to the Special Reference Laboratories for CH50 assay, we were able to classify 80 patients as C9-deficient using a sensitive screening test, as well as hemolytic and immunochemical C9 assays. The incidence of C9 deficiency was determined to be 0.086%, and there were no distinct differences among the eight areas of Japan tested. Serum CH50 levels of these C9-deficient patients varied widely (9.4-63.8 U/ml), and exhibited a higher value (average: 34.1 U/ml) than that of healthy C9-deficient individuals, probably due to elevated C3, C4, and C5 levels. These patients suffered from a variety of autoimmune, renal, and infectious diseases, which, however, are thought to be only incidentally associated with C9 deficiency.

Complement C9↗
PubMed1989

[Interaction between neuron and glia in the culture system].

Neuron and glia in culture produce varied trophic factors including extracellular matrix, growth factor cell adhesion factor, and cell growth inhibitory factor, and further secrete them into the culture medium. These factors are classified into two kinds of factors in the view-point of mechanism of action, an autocrine factor with the self-production and -stimulation, and a paracrine factor with the adjacent cell stimulation through the extracellular space but not via the blood stream. In the central nervous system, these trophic factors produced by both neuron and glia are thought to regulate the cell growth and differentiation of those cells by autocrine or paracrine system, and support the function of the central nervous system.

Animals↗
PubMed1989

[Vertebro-basilar artery occlusion in an 8-year-old boy].

An 8-year-old boy developed drowsy state, ataxia and right hemiparesis. Computed tomography and magnetic resonance imaging demonstrated ischemic lesions on bilateral cerebellar hemispheres, right thalamus and left pontine base. Angiography revealed occlusion of the left vertebral artery at the level of the second cervical spine and segmental narrowing of right vertebral artery from the level of the second to fifth cervical spine. Present case and previously reported cases suggest that vertebral artery could be stretched at the level of the second cervical spine and the intima may be injured to produce atherosclerosis.

Arterial Occlusive Diseases↗
PubMed1989

[Primary malignant mesothelioma of the pericardium masquerading as malignant pleural mesothelioma: report of an autopsy case and review of the reported cases in Japan as to its invasion to neighboring organs].

The Patient was a 72-year-old man who presented with dyspnea and general fatigue. Chest X-ray and CT-scan at the admission showed bilateral pleural effusion with collapse of the left lung and pericardial effusion. Cytology from the left pleural effusion suggested malignant mesothelioma. For this reason, malignant mesothelioma of the left pleura was diagnosed clinically and it was supposed to have spread subsequently to the pericardium. At autopsy, entire surface of the heart was found to be encroached in a diffuse fashion by a thick layer of mesothelioma tissues, which formed a small mass around the left pulmonary vein over the left atrium and invaded deep into the myocardium of all cardiac chambers. The endocardium and the intima of the left pulmonary vein were free of the invasion. The parietal pericardium adhered in places to the cardiac lesion, but no direct invasion to the adjacent pleurae through the pericardial wall was present. The left pleura over the lung and chest cavity disclosed only a superficial invasion by similar mesothelioma which was identifiable only on microscopic study. No distant metastasis was present in any thoracic and other organs as well as lymph nodes including the hilar ones of the lung. It seemed most likely from this anatomical finding that the primary site of the present mesothelioma was in the pericardium (visceral) and the tumor spread to the left pleura by a continuous extension along the outside of the left pulmonary vein. Primary malignant mesothelioma of the pericardium is of very rare occurrence and we found only 51 cases of it in the Japanese literature since 1915.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

The role of extraocular proprioception in vestibulo-ocular reflex of rabbits.

This study was undertaken to elucidate the role of extraocular proprioception in the vestibulo-ocular reflex, using pigmented rabbits. The presence of extraocular afferent projections in the ophthalmic branch (OB) of the trigeminal nerve was confirmed by retrograde transport of horseradish peroxidase. The OB of the left trigeminal nerve was transected at its junction with the trigeminal ganglion. Vestibular nystagmus was produced by rotating the animal clockwise and counter-clockwise in the horizontal plane in a dark room. The number and direction of the quick phase of nystagmus induced by rotation in the eye on the operated side were not different from those in the eye on the unoperated side or from those before the transection. However, the eye on the operated side moved slowly and unstably without directional preponderance during and after rotation at an angular velocity of 30 degrees/sec. In the sham-operated and unoperated groups, when the angular velocity was increased to over 90 degrees/sec, the eyes deviated in the anticompensatory direction to the head movement (the same direction as the head movement) during and immediately after the rotation. At an angular velocity of over 30 degrees/sec, however, the eye on the operated side exhibited anticompensatory response more frequently and markedly than that on the unoperated side. These results suggest that extraocular proprioception is important for fixation of the eye position in spacial relation to the head, and that loss of the sensation readily induces anticompensatory oculomotor response to head movement.

Animals↗