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Biomedical subjects

N Kojima

Publications and source records attributed to N Kojima.

At least 217 records · Page 12Linked to original sources
PubMed1986

[Magnetic resonance imaging in moyamoya disease].

Ten patients, seven children and three adults, with "moyamoya" disease were examined by MR-CT. MRI findings in these patients were compared with X-ray CT findings to study the features of the ischemic lesions in "moyamoya" disease and the following results were obtained. Old cerebral infarct, cortical atrophy and intracerebral hematoma in "moyamoya" disease were better delineated by image of the spin echo method. It is possible to differentiate the ischemic lesions such as ischemic edema, or acute or chronic cerebral infarct by calculating the T1 and T2 value from the T1 and T2 image. Ischemic lesions in "moyamoya" disease most often occurred in the watershed area of the anterior cerebral artery-middle cerebral artery or the middle cerebral artery-posterior cerebral artery, and these ischemic lesions were classified into three types according to the location of the lesion, i.e. cortical ischemic, subcortical ischemic and combined type. "Moyamoya" disease in the advanced stage, which was often seen in children, showed the combined type with poor outcome. From the above results, it might be concluded that MRI is superior to X-ray CT as a diagnostic aid to detect ischemic lesions in "moyamoya" disease.

Adolescent↗
PubMed1986

Effect of adriamycin entrapped by sulfatide-containing liposomes on ovarian tumor-bearing nude mice.

Sulfatide-containing liposomes showed the highest degree of adriamycin entrapment of all the liposomes tested. Adriamycin was bound to the sulfatide anions on the liposomal membrane, inserted into the membrane, and incorporated into the aqueous compartment of the vesicle. Liposome-entrapped adriamycin was maintained at a much higher blood level than free adriamycin, and reached a lower concentration in the heart than did the free drug, which might lead to lower cardiotoxicity of the drug. Incorporation of adriamycin into ovarian tumor transplanted into nude mice was increased when entrapped by the sulfatide-containing liposomes. Liposome-entrapped adriamycin did not induce the drastic loss of body weight which occurred with the free drug. The growth of ovarian tumor was inhibited by liposome-entrapped adriamycin to the same degree as free adriamycin. Having these advantages, sulfatide-containing liposomes could be useful carriers of adriamycin for cancer chemotherapy.

Animals↗
PubMed1985

[Investigations on the mechanism(s) of the production of anti-thyroid hormone antibodies 4: the effect of adjuvant on the immune response to human thyroglobulin].

Forty-five female DDYK mice were divided into three groups and immunized with different preparations of human thyroglobulin (HTg). Group 1 mice were immunized subcutaneously in the back with HTg emulsified with FCA. Group 2 mice were immunized subcutaneously in the back with HTg dissolved in PBS. Group 3 mice were immunized with HTg dissolved in PBS and FCA separately in the right (HTg) and left (FCA) of the back. After the fourth immunization (45 days after the first immunization), antisera as well as thyroid glands were obtained, and titers of anti-HTg, anti-T3, anti-T4 and the presence of lesions of autoimmune thyroiditis were examined. In group 1 mice, titers of anti-HTg and anti-T4 antibodies were significantly higher than those of the other two groups, whereas titers of anti-T3 antibodies were significantly lower than those of the other two groups. In group 1 mice, a significant correlation between titers of anti-T3 and anti-T4 antibodies was observed, whereas in group 2 and group 3 mice, no such correlation was observed. The incidence of lesions of autoimmune thyroiditis was significantly higher in group 2 and group 3 mice than in group 1 mice. Thus emulsification of HTg with FCA had inhibitory effects on the induction of experimental thyroiditis in mice immunized with HTg. These results indicate the possibility that FCA has a modulatory effect both quantitatively and qualitatively on the immune response against HTg in mice.

Animals↗
PubMed1985

Structural studies on the linkage unit between poly(N-acetylglucosamine 1-phosphate) and peptidoglycan in cell walls of Bacillus pumilus AHU 1650.

Structural studies were carried out on the polymer chains and their linkage regions in two kinds of teichoic acids, poly(N-acetylglucosamine 1-phosphate) [poly(GlcNAc-1-P)] and glycerol teichoic acid, bound to peptidoglycan in the cell walls of Bacillus pumilus AHU 1650. The poly(GlcNAc-1-P)-glycan complex isolated from lysozyme digests of the cell walls contained mannosamine and glycerol as minor components. On the basis of proton NMR spectroscopic data and isolation of N-acetylglucosamine 4-phosphate from acid hydrolysates, the poly(GlcNAc-1-P) was shown to be a polymer in which N-acetylglucosamine 1-phosphate units are joined at C-4 of the glucosamine residues. Mild alkaline hydrolysis of the poly(GlcNAc-1-P)-glycan complex gave a mannosamine-linked glycan fragment and the acidic polymer fraction that contained glycerol residues. Mild acid treatment of the mannosamine-linked glycan fragment gave the linkage disaccharide, ManNAc(beta 1----4)GlcNAc, whereas the acidic polymer fraction was degraded by this treatment into N-acetylglucosamine 4-phosphate and a glycerol-containing fragment characterized as P-(Gro-P)7 (Gro = glycerol). On the other hand, direct mild acid hydrolysis of the complex gave a fragment characterized as P-(Gro-P)7-ManNAc(beta 1----4)GlcNAc. These results lead to a conclusion that in the cell walls the poly(GlcNAc-1-P) chain is attached to peptidoglycan through a linkage unit, (Gro-P)7-ManNAc(beta 1----4)GlcNAc. By means of similar procedures, it was shown that the other cell wall polymer, glycerol teichoic acid, is also attached to peptidoglycan through the same disaccharide, ManNAc(beta 1----4)GlcNAc.

Acetylglucosamine↗
PubMed1985

Structural studies on the acidic polysaccharide of Bacillus cereus AHU 1356 cell walls.

Structural studies were carried out on the acidic polymer fraction isolated from lysozyme digests of the N-acetylated cell walls of Bacillus cereus AHU 1356. The acidic polymer fraction contained glucosamine, galactose, rhamnose, glycerol and phosphorus in a molar ratio of 1:1:2:1:1, together with small amounts of glycopeptide components and muramic acid 6-phosphate. The hydrogen fluoride treatment led to removal of glycerol and phosphorus from the polymer without loss of other components. Results of the NaIO4 oxidation, methylation and proton magnetic resonance spectroscopy of the native and dephosphorylated preparations, in combination with data of the analysis of oligosaccharides obtained from partial hydrolysis of polysaccharide, led to the most likely structure of the repeating units of the acidic polysaccharide chain, ----4)N-acetylglucosaminyl-(alpha 1----3)rhamnosyl(alpha 1----3)galactosyl(alpha 1----4)[sn-glycerol 1-phospho-2]rhamnosyl(alpha 1----.

Bacillus cereus↗
PubMed1985

Structural studies on the linkage unit of ribitol teichoic acid of Lactobacillus plantarum.

Structural studies were carried out on the linkage unit which joins ribitol teichoic acid to peptidoglycan in the cell walls of Lactobacillus plantarum AHU 1413. The heating of the cell walls at pH 2.5 led to release of only 5% of ribitol teichoic acid components as water-soluble material. In contrast, the same treatment of the cell walls after N-acetylation led to release of about 80% of the teichoic acid moiety, giving a teichoic-acid-linked sugar preparation which contained about equimolar amounts of mannosamine, glucosamine and glycerol as minor components. The teichoic-acid-linked sugar was hydrolyzed by mild alkaline treatment into a disaccharide, N-acetylmannosaminyl(beta 1----4)N-acetylglucosamine and ribitol teichoic acid linked to glycerol. The Smith degradation of the N-acetylated cell walls gave a characteristic fragment, 1,2-ethylenediol-phospho-glycerol-phospho-N-acetylmannosaminyl(beta 1----4) N-acetylglucosamine. Furthermore, when the intact cell walls were subjected to the NaNO2 treatment followed by NaBH4 reduction, the ribitol teichoic acid moiety was recovered for the most part in the water-soluble polymer fraction, from which a sugar, N-acetylmannosaminyl-2,5-anhydromannitol, was released by mild alkaline treatment. These results lead to the conclusion that the ribitol teichoic acid chain in the intact cell walls of this organism is linked to peptidoglycan through a unique linkage unit, glycerol-phospho-N-acetylmannosaminyl(beta 1----4)-glucosamine. The anomalous stability of the linkage between the teichoic acid moiety and peptidoglycan against acid hydrolysis seems to be accounted for by the involvement of the N-substituted glucosamine residue in the phosphodiester bridge that joins the two polymers.

Binding Sites↗
PubMed1985

A common linkage saccharide unit between teichoic acids and peptidoglycan in cell walls of Bacillus coagulans.

Teichoic acid-glycopeptide complexes were isolated from lysozyme digests of the cell walls of Bacillus coagulans AHU 1631, AHU 1634, and AHU 1638, and the structure of the teichoic acid moieties and their linkage regions was studied. On treatment with hydrogen fluoride, each of the complexes gave a hexosamine-containing disaccharide, which was identified to be glucosyl(beta 1----4)N-acetylglucosamine, in addition to dephosphorylated repeating units of the teichoic acids, namely, galactosyl(alpha 1----2)glycerol and either galactosyl(alpha 1----2)[glucosyl(alpha 1----1/3)]glycerol (AHU 1638) or galactosyl(alpha 1----2)[glucosyl(beta 1----1/3)]glycerol (AHU 1631 and AHU 1634). From the results of Smith degradation, methylation analysis, and partial acid hydrolysis, the teichoic acids from these strains seem to have the same backbone chains composed of galactosyl(alpha 1----2)glycerol phosphate units joined by phosphodiester bonds at C-6 of the galactose residues. The presence of the disaccharide, glucosyl(beta 1----4)N-acetylglucosamine, in the linkage regions between teichoic acids and peptidoglycan was confirmed by the isolation of a disaccharide-linked glycopeptide fragment from each complex after treatment with mild alkali and of a teichoic acid-linked saccharide from each cell wall preparation after treatment with mild acid. Thus, it is concluded that despite structural differences in the glycosidic branches, the teichoic acids in the cell walls of the three strains are linked to peptidoglycan through a common linkage saccharide, glucosyl (beta 1----4) N-acetylglucosamine.

Bacillus↗
PubMed1985

Structure of the linkage units between ribitol teichoic acids and peptidoglycan.

The structure of the linkage regions between ribitol teichoic acids and peptidoglycan in the cell walls of Staphylococcus aureus H and 209P and Bacillus subtilis W23 and AHU 1390 was studied. Teichoic acid-linked saccharide preparations obtained from the cell walls by heating at pH 2.5 contained mannosamine and glycerol in small amounts. On mild alkali treatment, each teichoic acid-linked saccharide preparation was split into a disaccharide identified as N-acetylmannosaminyl beta(1----4)N-acetylglucosamine and the ribitol teichoic acid moiety that contained glycerol residues. The Smith degradation of reduced samples of the teichoic acid-linked saccharide preparations from S. aureus and B. subtilis gave fragments characterized as 1,2-ethylenediol phosphate-(glycerolphosphate)3-N-acetylmannosaminyl beta(1----4)N- -acetylxylosaminitol and 1,2-ethylenediolphosphate-(glycerol phosphate)2-N-acetylmannosaminyl beta(1----4)N-acetylxylosaminitol, respectively. The binding of the disaccharide unit to peptidoglycan was confirmed by the analysis of linkage-unit-bound glycopeptides obtained from NaIO4 oxidation of teichoic acid-glycopeptide complexes. Mild alkali treatment of the linkage-unit-bound glycopeptides yielded disaccharide-linked glycopeptides, which gave the disaccharide and phosphorylated glycopeptides on mild acid treatment. Thus, it is concluded that the ribitol teichoic acid chains in the cell walls of the strains of S. aureus and B. subtilis are linked to peptidoglycan through linkage units, (glycerol phosphate)3-N-acetylmannosaminyl beta(1----4)N-acetylglucosamine and (glycerol phosphate)2-N-acetylmannosaminyl beta(1----4)N-acetylglucosamine, respectively.

Bacillus subtilis↗
PubMed1985

Vertebral artery occlusion at the narrowed "scalenovertebral angle": mechanical vertebral occlusion in the distal first portion.

We report a patient who developed occasional vertigo when turning his head to the right side. Occlusion of the right vertebral artery occurred at the narrowed "scalenovertebral angle" with this rotational head movement. This triangular tunnel consisted of the hypertrophied ligament of the longus colli muscle and the anterior scalene muscle. Decompression of these extraluminal compressive factors led to relief of the symptoms. Two different kinds of extrinsic compression at the first portion of the vertebral artery are discussed.

Arterial Occlusive Diseases↗
PubMed1985

[Visual field defects in hydrocephalus].

Eight patients representing visual field defects associated with hydrocephalus are reviewed. Seven cases had aqueductal stenosis and one had congenital communicating hydrocephalus. We found five cases of defects in visual field typical of a chiasmal or optic nerve lesion: (1) inferior altitudinal hemianopia with inferior nasal quadrantanopia in the opposite eye; (2) inferior binasal quadrantanopia; (3) unilateral inferior nasal depression; (4) unilateral temporal defect; (5) bilateral central scotoma. In these cases CT demonstrated moderate or marked symmetrical dilatation of the third and lateral ventricles. Four out of five cases showed bulging of the third ventricle anteriorly into the sella turcica on CT or ventriculography. Other three patients had incongruous homonymous hemianopia. Characteristic asymmetrical dilatation of the lateral ventricles was noted in all three cases. The more enlarged lateral ventricles were ipsilateral with the affected visual pathways. The sites of lesion responsible for these field defects seemed to be optic tract in one case and optic radiation in two cases. Ventriculoperitoneal shunt was placed in five out of seven cases. Impaired visual field improved in three patients after shunt insertion. A 28-year-old female who had history of blurred vision fos 14 days showed improvement in visual acuity and field when the enlarged ventricles became slit-like by shunting. In the other two patients defects in visual fields improved in spite of consistent ventriculomegaly. These facts suggested that not only the mechanical forces with distended third ventricle but also increased intracranial pressure played an important role in producing visual field defects in hydrocephalic patients.

Adolescent↗
PubMed1984

Reversible congruous homonymous hemianopia as a symptom of shunt malfunction.

Congruous left homonymous hemianopia occurred as a symptom of ventriculoperitoneal shunt malfunction. The low attenuation along the ventricular catheter in the right occipital area that was seen on a computed tomography scan disappeared after revision of the shunt, and corresponded with improvement of this peculiar visual field symptom. In view of anatomic considerations and clinical course, this homonymous field defect might be caused by peritubular cerebrospinal fluid edema in the right occipital area. In evaluating the patients having shunts, precise neuroophthalmologic examination should be performed for possible visual field defects.

Cerebrospinal Fluid Shunts↗
PubMed1984

Enzyme-histochemical studies on the nonsecretory neurons of the rat supraoptic nucleus with the application of karyometry and electronmicroscopy.

Detailed histochemical studies were conducted on the distribution of SDH, G6PD, and TPPase as well as the Nissl substance and Gomori-positive material in the nonsecretory neurons of the supraoptic nucleus (SO) of the adult Wistar strain rats. Karyometry and statistical analysis were performed to identify those neurons. Electron microscopy confirmed the cytological characteristics indicated by the histochemical results. Based on the classification of SO neurons by the Golgi-Cox method and the present results concerning the Nissl pattern, shape, size, and number, these nonsecretory neurons appear to be intercalated neurons. Weak SDH and G6PD activity in the perikaryon with a few mitochondria indicate that they belong to the category of ordinary neurons with a low level of carbohydrate metabolism. The TPPase reaction revealed heterogeneous Golgi apparatus (GA) with poor development. In addition, it was difficult to find profiles of GA in many ultrathin sections. These results indicate that the GA may not undergo cyclic activity and lacks the capacity for secretion. No Gomori-positive material was detected in the perikaryon, whereas the Nissl substance was densely distributed throughout the entire perikaryon, where many free ribosomal rosettes and junctions of cisternae of abundant granular reticulum were evenly dispersed. The nonsecretory neurons reflect an active phase of cyclic activity of protein synthesis. However, other nonsecretory neurons with less active protein synthesis are very likely to be present.

Animals↗
PubMed1984

Suppression of IgE antibody response by preadministration of antigen-pulsed spleen cells. II. Characteristics of immediate tolerance induction.

Intravenous administration of syngeneic spleen cells (SPC), briefly pulsed with antigen in vitro, resulted in a profound state of IgE antibody unresponsiveness. One of the mechanisms of this unresponsiveness is responsible for an immediate tolerance which is induced without any suppressor cells. Characteristics of this immediate tolerance were investigated. Administration of antigen-pulsed spleen cells 4 h before the immunization, suppressed the production of IgE antibody triggered by the subsequent immunization. Pretreatment with cyclophosphamide had no effect on this rapid suppression, and this suppressive state could not be transferred to normal syngeneic recipients by the injection of spleen cells from the tolerant mice used in our experiment. These observations suggest that suppressor cells do not play an important role in immediate tolerance. The extent of this immediate tolerance induced by the injection of antigen-pulsed SPC depends on the number of antigen-pulsed SPC and the dose of antigen to which SPC had been exposed. Injection route of antigen-pulsed SPC has a great influence on the induction of immediate tolerance. The order of suppressive extent is intravenous, greater than intraperitoneal greater than subcutaneous. This suppression is specific to the antigen pulsed to SPC. Carrier-specific T cells are the major target of suppression in immediate tolerance. Antigen-pulsed T cells induce immediate tolerance most effectively in the subpopulations of SPC.

Animals↗
PubMed1984

Serum thyroglobulin concentration in normal pregnancy.

We measured the levels of serum thyroglobulin (Tg) in 52 pregnant females at various stages and compared them with those of 15 age-matched nonpregnant females. Serum Tg was measured by a solid-phase immunoradiometric assay. In pregnant females, mean serum Tg levels at the first, second, early third, and late third trimesters were 8.4 (range; 1.3-18.0), 9.2 (1.7-25.6), 10.1 (1.8-22.8), and 12.1 ng/ml (5.3-25.2), respectively. The statistical comparison was made after logarithmic transformation of the data. The mean value only at the late third trimester was significantly higher than that of controls (mean; 6.0 ng/ml, range; 1.5-23.6), but each value was within the normal range. Although serum Tg levels have been reported to be high at the end of pregnancy, our results indicate that the Tg levels in females could be clinically interpreted without regard to the coexistence of pregnancy.

Adult↗
PubMed1984

[Experimental model of venous hemorrhagic infarction by cerebral sinus occlusion].

A new experimental model of the hemorrhagic infarction was devised to study the pathophysiology of the hemorrhagic infarction of the venous origin. To make a model of the hemorrhagic infarction by sinus occlusion, mixture of alpha-cyanoacrylate monomer and pantopaque was injected through a catheter introduced into the superior sagittal sinus in 15 dogs, using embolization technique. These dogs were divided into three groups according to the volume of the mixture injected into the sinus. In control groups (3 dogs), no mixture was injected. For partial sinus occlusion (5 dogs), 0.5-1.0 ml of mixture was injected into the sinus and 1.0-1.5 ml of mixture, for complete sinus occlusion (7 dogs). Changes of intracranial pressure (ICP), superior sagittal sinus pressure (SSSP), tissue pressure (TP) rCBF and histological changes were evaluated before and after sinus occlusion. The following results were obtained. (1) In control groups, ICP, SSSP and TP were 9 +/- 2.2 mmHg, 4 +/- 2.5 mmHg and 4-5 mmHg respectively, but in partial and complete sinus occlusion, SSSP and TP were higher than ICP. ICP, SSSP & TP were 32 +/- 5.4 mmHg, 35 +/- 6.5 mmHg and 37-42 mg, in partial sinus occlusion and 62 +/- 5.9 mmHg, 65 +/- 6.0 mmHg, 65-72 mmHg in complete sinus occlusion. (2) R-CBF in partial sinus occlusion showed no change even after sinus occlusion, but in complete sinus occlusion, decreased to 20% of that of the control group due to marked venous congestion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Further characterization of the potentiometric behavior of cytochrome oxidase. Cytochrome alpha stays low spin during oxidation and reduction.

An improved device for potentiometry using magnetic circular dichroism spectroscopy has been developed and used to characterize the potentiometric behavior of solubilized beef heart cytochrome oxidase. In the absence of inhibitors, the electron affinity of cytochromes alpha and alpha 3 are indistinguishable and adequately described by the allosteric model of Nicholls and Peterson (Nicholls, P., and Peterson, L. C. (1972) Biochim. Biophys. Acta 357, 462-467). All of the cytochrome alpha can be accounted for as low spin heme throughout the titration. Cytochrome c present at 1:1, 2:1, and 4:1 stoichiometry with cytochrome alpha did not significantly affect the potentiometric behavior of alpha or chondroitinase alpha 3; at the 1:1 ratio the midpoint potential of cytochrome c was lowered by about 30 mV. In the presence of formate, azide and cyanide cytochrome alpha assumed approximately n = 1 behavior. However, the response of alpha 3 differed with each reagent and was particularly complex in the presence of azide. Fluoride produced very small changes in the potentiometric behavior suggesting that it may not be a ligand to cytochrome alpha 3. Possible deficiencies in the allosteric model are examined.

Animals↗
PubMed1983

[Production of antithyroid hormone antibodies. 2. Genetic control of the production of anti-human thyroglobulin and antithyroid hormone antibodies in mice immunized with human thyroglobulin].

Recently anti-thyroid hormone antibodies have been found in many cases of thyroidal and non-thyroidal disorders. However, the exact mechanism(s) of production of anti-thyroid hormone antibodies in these patients is so far obscure. Thyroxine (T4) and triiodothyronine (T3) are haptens and are not immunogenic in free form. In this respect, human thyroglobulin (HTg) has long been suggested as an antigen of the anti-thyroid hormone antibodies observed in them because it carries thyroid hormones on its surface. In our previous communication, we reported the production of anti-HTg antibodies and anti-thyroid hormone antibodies in two rabbits and various strains of mice immunized with HTg. In order to elucidate the gene(s) which controls the production of anti-HTg and anti-thyroid hormone antibodies, various strains of mice which have different H-2 and Igh allotypes were immunized with HTg. The titers of anti-HTg and anti-thyroid hormone antibodies were measured, and the locus (loci) which controls the immune response against them was determined. Our present investigation has revealed that the Ir-gene(s) which controls the production of anti-HTg and anti-T4 antibodies is located in the I-A subregion. Concerning the production of anti-T4 antibodies in mice, the presence of Ir-gene(s) outside of H-2 is also suggested. The significance of the genetic mechanisms controlling the immune response against thyroid hormones in various thyroidal disorders is discussed.

Animals↗