Biomedical subjects
M Ichikawa
Publications and source records attributed to M Ichikawa.
[Usefulness of continuous peritoneal dialysis (CPD) in the management of metabolic encephalopathy in adult type citrullinemia].
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[Differentiation of the origins of hematuria based on the volume distribution curve of urinary red blood cells].
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[Congenital muscular dystrophy (Fukuyama type) with imperforate anus].
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Freeze-substitution for thin-section study of biological specimens.
Freeze-substitution as a preparation technique for frozen specimens is briefly reviewed. Recent advance in cryotechniques, especially quick freezing followed by freeze-substitution, has made it possible to preserve the ultrastructural features of cells and tissues to reflect more closely their living state and capture transient physiological processes as evanescent as fusion and fission of biological membranes. The technique is also advantageous to retain soluble substances of the cellular components. Thus, histochemical, autoradiographic and/or immunocytochemical analyses of quick-frozen, substitution-fixed samples allow us to obtain more precise localization of chemical components in cells than in the case of conventional chemical fixation. Several examples indicating the superiority of the preparatory method are presented.
[Intraarterial injection therapy of CDDP-PC-lipiodol suspension for hepatoma].
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[The effect of purification procedures on the determination of serum level of 1,25-dihydroxyvitamin D].
The advance in knowledge of clinical disorders involving calcium and bone diseases has resulted in part from the development of assay procedures for the major vitamin D metabolites, but the values of the same samples measured in different laboratories vary considerably. They suggest that the chromatographic purification involved in these assays seems to be a critical step. In this study, we compared the results of 1,25-dihydroxyvitamin D (1,25(OH)2D) using different chromatographic purification methods: Sephadex LH-20 column chromatographic purification (non-HPLC method) described by Mallon et al. and High Performance Liquid Chromatographic purification (HPLC method) modified by Yamaoka et al. Serum 1,25(OH)2D levels of healthy volunteers before and after oral load of 4 micrograms of 1 alpha-hydroxyvitamin D3 (1 alpha OHD3) were measured by the two different methods mentioned above. A good correlation (r = 0.951, p less than 0.001) was noted in the samples before loading. The mean values of serum 1,25(OH)2D before loading did not differ significantly between HPLC method and non-HPLC method. After loading, however, the mean value of serum 1,25(OH)2D was significantly higher in non-HPLC method (p less than 0.01). The values of 1,25(OH)2D were determined in the serum added 1,25-dihydroxy-24-oxo-vitamin D3 (24-oxo-D3) (0 pg/ml, 200 pg/ml or 2000 pg/ml). In the samples added 2000 pg/ml of 24-oxo-D3, the mean value of 1,25(OH)2D was significantly higher in non-HPLC method (p less than 0.001). The affinity of 24-oxo-D3 for 1,25(OH)2D3 cytosolic receptor was evaluated in chick embryo intestinal mucosa and rachitic chick intestinal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)
Plasticity of intra-amygdaloid connections following the denervation of fibers from accessory olfactory bulb to medial amygdaloid nucleus in adult rat: immunohistochemical study of anterogradely transported lectin (Phaseolus vulgaris leucoagglutinin).
The rearrangement of the terminations of intra-amygdaloid fibers was examined in the medial amygdaloid nucleus (MAN) following denervation of the fibers from the accessory olfactory bulb (AOB) of adult rat using immunohistochemistry of anterogradely transported lectin (Phaseolus vulgaris leucoagglutinin, PHA-L). The AOB was removed unilaterally by suction at two months before the PHA-L injection. The PHA-L was injected bilaterally into the posteromedial region of the amygdala (posteromedial amygdaloid nucleus and amygdala-hippocampal transitional area). After the tissue was processed by the routine immunohistochemical method, the immunologically labeled axons and axon terminals in the MAN were observed with the light microscope. On the control side, labeled axons were observed in the cellular part of the MAN, but they were not found in the molecular layer in which the fibers from the accessory olfactory bulb terminate. On the side of the AOB removal, the labeled axons were found not only in the cellular part but also in the molecular layer. Electron microscopic observations showed that the labeled axon terminals made synaptic contacts in the molecular layer. These results indicate that terminals of intra-amygdaloid fibers expand from the cellular part to the molecular layer in the MAN and make synaptic contacts in this layer following the denervation of the AOB fibers.
Roles of the beta-D-ribofuranose ring and the functional groups of the D-ribose moiety of adenosylcobalamin in the diol dehydratase reaction.
Four analogs of adenosylcobalamin (AdoCbl) modified in the D-ribose moiety of the Co beta ligand were synthesized, and their coenzymic properties were studied with diol dehydratase of Klebsiella pneumoniae ATCC 8724. 2'-Deoxyadenosylcobalamin (2'-dAdoCbl) and 3'-deoxyadenosylcobalamin (3'-dAdoCbl) were active as coenzyme. 2',3'-Secoadenosylcobalamin (2',3'-secoAdoCbl), an analog bearing the same functional groups as AdoCbl but nicked between the 2' and 3' positions in the ribose moiety, and its 2',3'-dialdehyde derivative (2',3'-secoAdoCbl dialdehyde) were totally inactive analogs of the coenzyme. It is therefore evident that the beta-D-ribofuranose ring itself, possibly its rigid structure, is essential and much more important than the functional groups of the ribose moiety for coenzymic function (relative importance: beta-D-ribofuranose ring much greater than 3'-OH greater than 2'-OH greater than ether group). With 2'-dAdoCbl and 3'-dAdoCbl as coenzymes, an absorption peak at 478 nm appeared during enzymatic reaction, suggesting homolysis of the C-Co bond to form cob(II)alamin as intermediate. In the absence of substrate, the complexes of the enzyme with these active analogs underwent rapid inactivation by oxygen. This suggests that their C-Co bond is activated even in the absence of substrate by binding to the apoprotein. No significant spectral changes were observed with 2',3'-secoAdoCbl upon binding to the apoenzyme. In contrast, spectroscopic observation indicates that 2'3'-secoAdoCbl dialdehyde, another inactive analog, underwent gradual and irreversible cleavage of the C-Co bond by interaction with the apodiol dehydratase, forming the enzyme-bound cob(II)alamin without intermediates.
Determination of gamma-aminobutyric acid and associated amino acids in mouse brain by liquid chromatography.
A rapid method is described for the analysis of amino acids containing in mouse brain by high performance liquid chromatography equipped with a fluorescence detector. Pre-column o-phthalaldehyde-2-mercaptoethanol derivatives of the amino acids were injected onto an ODS C-18 column. 5-Amino-n-valeric acid, a non-endogenous amino acid, was used as an internal standard. Separation and elution of amino acid derivatives were achieved by varying the ratio of organic phase by a step gradient. Significant increases in gamma-aminobutyric acid, glutamine and glycine levels in the brain were detected 2 h after injection of 800 mg/kg valproic acid (VPA). A high dose administration of VPA was correlated with Reye's syndrome.
Effect of sodium valproate (VPA) on cerebral amino acids: mechanism of gamma-aminobutyric acid (GABA) elevation and possible causal relation of VPA-induced encephalopathy and glutamine level.
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[A case of Conn's syndrome improving after adrenal extravasation].
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Epithelium-lined cyst ventral to the medulla oblongata in an infant--case report.
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Long-term effect of energy restriction at different protein levels on several parameters of nutritional assessment.
Experiments were conducted to evaluate long-term effects of energy restricted diets containing different protein levels initiated in adult life on various parameters of nutritional assessment. Rats (male SPF Wistar) were fed 20%-casein diet ad libitum, or 10%-, 20%-, or 40%-casein diets (group 10R, 20R, and 40R, respectively) under energy-restricted conditions, which corresponded to about 60% ad libitum feeding, from 18 to 55 weeks of age. Energy restriction induced a decrease of body-lipid percentage. Although skeleton weight and tail length increased throughout the experimental period in all the groups, these increases were found to be depressed under energy restriction. On the other hand, protein intake level under the energy restriction did influence plasma concentrations of urea and cholesterol, hematocrit, and systolic blood pressure. The group fed the 40%-casein diet tended to be lower in total cholesterol levels at 55 weeks of age, while the group fed 10%-casein diet tended to be lower in hematocrit and higher in systolic blood pressure levels. When mature rats were fed the 60%-energy-restricted diet for a long-term period, those on the 20%- and 40%-casein diets showed somewhat more preferable levels of hematocrit and blood pressure than those on the 10%-casein diet; the 10%-casein diet did not, however, reveal symptoms of malnutrition.
[A case of ulcerative colitis associated with Takayasu's arteritis].
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Spontaneous improvement of juvenile rheumatoid arthritis after T lymphocytosis with suppressor phenotype and function.
Spontaneous improvement of active juvenile rheumatoid arthritis (JRA) occurred after T lymphocytosis in an 8-year-old boy. He had prominent lymphocytosis, the count reaching 59,000/mm3, followed by spontaneous disappearance of fever, arthralgia, lymphadenopathy, hepatomegaly, and C-reactive protein. The serum immunoglobulin levels were gradually decreased. The surface marker analysis, using two color flow cytometry, showed that the lymphocytes were activated suppressor T lymphocytes, expressing CD3, CD8, HLA-DR, and CD8 plus CD11. When studied in vitro with pokeweed mitogen stimulation, the T lymphocytes significantly suppressed the immunoglobulin production by autologous B lymphocytes as compared with the T lymphocytes at remission (p less than 0.01). Based on the widely believed notion that depression of suppressor T lymphocyte functions is one of the important mechanisms underlying systemic JRA, the activated T lymphocytosis with the suppressor phenotype and suppressive function on the immunoglobulin production may have been related to the improvement of active JRA in the patient.
[Family therapy for alcoholics].
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Defective interleukin-1 production in a familial monocyte disorder with a combined abnormality of mobility and phagocytosis-killing.
Monocytes in a familial monocyte disorder, a recently recognized primary immunodeficiency syndrome, with impaired phagocytic functions were studied for their ability to produce interleukin 1 (IL-1) as well as the surface property. Monocytes from two children (siblings) with the disorder possessed CD11b, CD13, CD14, CD33, Ia and LFA-1/Mac-1/p150,95 beta subunit antigens as determined by flow cytometry. Electron microscopic cytochemistry showed that the monocytes had surface glycoproteins reactive with four representative lectins. The IL-1 production by monocytes was assayed in the two patients and compared with that in six children with primary immunodeficiency syndromes and some monocyte abnormalities; three had congenital neutropenia, two had hyper-IgE syndrome, and one had defective monocyte chemotaxis. Monocyte culture supernatants were prepared with stimulation by lipopolysaccharide or silica, and their IL-1 activity was measured by the mouse thymocyte-proliferation assay. The patients' monocytes were defective in IL-1 production: the values were less than 1.0% of the control monocyte values (n = 12) and were in contrast with those of congenital neutropenia monocytes of 186.2% to 204.3%. These results demonstrate a familial monocyte disorder which is characteristic among the immunodeficiency syndromes with regard to the defective IL-1 production and the impaired phagocytic functions.