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Biomedical subjects

K Ichikawa

Publications and source records attributed to K Ichikawa.

At least 271 records · Page 15Linked to original sources
PubMed1993

Long-term culture of primary rat hepatocytes with high albumin secretion using membrane-supported collagen sandwich.

Primary cultured rat hepatocytes in a membrane-supported collagen sandwich maintained their normal cell morphology and high level of albumin secretion for over 56 days. It was found that the existence of an upper layer of collagen gel is crucial for long-term culture and that the transference of cellular nutrients between the culture media and hepatocytes from both the upper and the lower sides of gel layers promotes albumin secretion. These facts suggest that the membrane-supported collagen sandwich mimics well the in vivo environment of hepatocytes. This method has great potential for the long-term culture of primary cells.

Albumins↗
PubMed1993

Role of dehydroepiandrosterone and dehydroepiandrosterone sulfate for the maintenance of axillary hair in women.

To delineate the relationship between sex hormones and the axillary hair in women, serum concentrations of dehydroepiandrosterone, dehydroepiandrosterone sulfate and testosterone were measured in 177 normal women (aged 16 to 76 y). Both menstrual cycle and axillary hair were present in all normal women younger than 50 years. In the 6th decade, axillary hair was present in 21 of 42 normal women but menstruation was present only in 8 of the 42 women. In the 7th and 8th decades, axillary hair was present in 36% and 25% of them, respectively. None of the subjects over 60 years of age had a menstrual cycle. Serum dehydroepiandrosterone and dehydroepiandrosterone-sulfate concentrations were significantly higher in axillary hair-positive than in -negative women after 50 years of age. Serum testosterone concentration was low in normal women after 50 years of age compared to those of under 49 years, and it was marginally lower in axillary hair-negative than in -positive normal women. However the difference between the axillary hair-positive and -negative subjects was not statistically significant. It is suggested that weak adrenal androgens such as dehydroepiandrosterone and dehydroepiandrosterone-sulfate, rather than testosterone, play an important role for the maintenance of axillary hair in aged women.

Adolescent↗
PubMed1993

Expression of anticardiolipin cofactor, human beta 2-glycoprotein I, by a recombinant baculovirus/insect cell system.

A full-length cDNA coding a human beta 2-glycoprotein I (beta 2-GPI) was introduced into the baculovirus genome to construct a recombinant baculovirus. Spodoptera frugiperda (Sf9) cells were infected with the recombinant baculovirus. A protein (mol. wt 43,000) reactive with anti-beta 2-GPI antisera was produced in the insect cells and secreted into the culture medium. The recombinant beta 2-GPI was purified from the culture supernatant by sequential cardiolipin (CL)-affinity column chromatography and gel filtration. The N-terminal amino acid sequence of the protein was identical to that of the native beta 2-GPI purified from human sera, and a putative signal peptide was cleaved from the secreted form of the recombinant protein. The purified recombinant protein had a cofactor activity which enhances CL binding of anticardiolipin antibodies (aCL) in systemic lupus erythematosus (SLE) patients, as well as the native beta 2-GPI. Thus, the beta 2-GPI expressed in insect cells is an immunologically active cofactor.

Amino Acid Sequence↗
PubMed1993

Inhibition of myosin light chain phosphatase during Ca(2+)-independent vasocontraction.

Phorbol 12,13-dibutyrate (PDB) induced a sustained contraction of rat thoracic aorta strip in Ca(2+)-free buffer without significant change in intracellular free Ca2+ concentration. NKH477, a water-soluble forskolin derivative, markedly relaxed the PDB-induced contraction. The PDB-induced contraction was associated with the phosphorylation of 20-kDa myosin light chain (MLC). Two-dimensional phosphopeptide mapping of 20-kDa MLC revealed that approximately 90% of the phosphopeptides was derived from an MLC kinase-catalyzed reaction and approximately 10% was due to phosphorylation by protein kinase C. NKH477 inhibited the PDB-induced phosphorylation of 20-kDa MLC. MLC phosphatase activity of intact aorta strips was inhibited by the treatment with PDB, and the inhibition was recovered by the application of NKH477. These results suggest that the regulation of MLC phosphatase in vascular smooth muscle may play important roles in the PDB-induced contraction and the NKH477-induced relaxation in Ca(2+)-free buffer.

Animals↗
PubMed1993

Secretion and overproduction of carboxypeptidase Y by a Saccharomyces cerevisiae ssl1 mutant strain.

Carboxypeptidase Y (CPY; EC 3.4.16.1) is the yeast vacuolar protease. To have CPY secreted and to increase its secretion level, we tried to express the prepro-CPY gene under the control of the inducible GAL10 promoter or constitutive ENO1 promoter on a multicopy plasmid. In the strains KK4, PEP4, and A2-1-1A, carrying the CPY expression plasmid, active CPY was not detected in the culture broth although the CPY activity was greatly increased inside the cells. In contrast, when we used a strain that contained the ssl1 (super-secretion of lysozyme) mutation, a large amount of active CPY (about 10-50 mg/liter) was detected in the culture broth. The ssl1 mutants secreted active CPY when the CPY level was increased by expressing it under the control of a strong promoter on a multicopy plasmid, while the endogenous expression of chromosomal CPY gene in the same ssl1 mutant caused a deficiency in the processing of pro-CPY to mature CPY.

Base Sequence↗
PubMed1993

An outbreak of Salmonella typhimurium infection in bengalees, a variety of Lonchura striata.

Bengalees (a variety of Lonchura striata) in an aviary in Nagano Prefecture died of severe diarrhea in 1991. Pathological examination revealed slight enlargement of the liver and spleen. Histopathologically, necrotic granulomatous lesions were seen in the liver. Salmonella Typhimurium was isolated from the main organs and fecal samples. No evidence of Newcastle disease or chlamydiosis was detected. The disease was finally diagnosed as S. Typhimurium infection in bengalees. In spite of some countermeasures, 198 out of 268 birds died within 6 months, a mortality rate of 74%. Epizootiological survey revealed that the infection was transmitted by birds introduced from another prefecture. This is the first report of S. Typhimurium infection in bengalees.

Animals↗
PubMed1993

Induction of cytosolic triiodo-L-thyronine (T3) binding protein (CTBP) by T3 in primary cultured rat hepatocytes.

Cytosolic 3, 5, 3'-triiodo-L-thyronine (T3)-binding protein (CTBP) plays an important role in the regulation of intracellular T3 translocation from cytoplasm to the nuclear T3 receptor. We examined whether the CTBP activity could be induced by T3 or not in cultured hepatocytes prepared from thyroidectomized rats. CTBP activity was not detected in primary cultured hepatocytes from thyroidectomized rats. However, the protein was induced by the addition of T3 to the culture medium. The increase in the activity of CTBP was time dependent and the maximal level was obtained by 48 h in the presence of 300 nM T3. CTBP activity was also increased by retinol (35 microM) or by 1,25-(OH)2-vitamin D3 (10 nM). On the other hand, the activity of malic enzyme (ME) was induced by the addition of T3 to the culture medium. The maximal activity of ME was obtained by 48 h in the presence of 300 nM T3. The increase in ME activity was also induced by retinol or 1,25-(OH)2-vitamin D3. These results suggested that not only ME activity but also CTBP activity is induced by T3. Further, retinol and vitamin D3 have similar effects on the induction of CTBP activity and ME activity.

Animals↗
PubMed1993

n-Butyrate enhances induction of thyroid hormone-responsive nuclear protein.

Effects of n-butyrate on nuclear thyroid hormone receptors and on thyroid hormone-responsive nuclear protein were investigated by means of a perfusion system in rat liver. Treatment with 5 mM n-butyrate resulted in an increase (150%) in the maximal binding capacity of 3,5,3'-L-triiodothyronine (T3) nuclear receptors without altering the affinity of receptor for T3. However, further perfusion for 4 h decreased the number of the receptors to the control level. n-Butyrate increased the amount of acetylated histone H4. The ability of nuclear T3 receptors to bind to core histones was diminished by acetylation of the core histones. Thyroid hormone-responsive nuclear protein (n protein) was increased by T3. The induction of the n protein by T3 was augmented by n-butyrate. These results suggested that n-butyrate modulates thyroid hormone-responsive gene expression in rat liver via the increased number of nuclear receptors or changes in the chromatin constitution.

Acetylation↗
PubMed1993

[Immunological aspects of asthmatic children in remission].

Allergen-activated T cells secrete several kinds of bioactive lymphokines such as IL2, IL3, IL4, IL5 and IFN-gamma. They function as helpers in IgE production involved in immediate type hypersensitivity and/or effector cells in delayed type hypersensitivity in allergic patients. The acquisition of interleukin 2 (IL2) responsiveness by specific antigen-stimulated cells is generally an essential event for the induction of specific immunological phenomena. To investigate the immunological changes in asthmatic children in remission, the induction of IL2-responsiveness and production by Df (Dermatophagoides farinae)-stimulated patient lymphocytes, and Df-induced IFN-gamma production by patient lymphocytes were evaluated. The patients were divided into 3 groups. The remission group (I) consisted of those patients who had had no or only a few asthmatic attacks for more than 2 years without medication. The group of active asthma were divided into 2 groups according to attack frequency and severity (II, partial remission; III, active asthma). IL2 responsiveness and production by Df-stimulated lymphocytes from group II and III were increased. As symptoms improved, the extent of the response subsided to a level comparable to that of normal individuals (group III). IFN-gamma production by Df-stimulated lymphocytes from patients with active asthma was lower than that of normal lymphocytes. In contrast, lymphocytes from patients in complete remission group (I) induced far greater IFN-gamma generation than those from normal and group II and III patients in a Df antigen-dependent manner, which might downregulate Df-induced hyperreactivity for Df-mediated allergic response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Polyneuropathy with IgM-antibody to myelin-associated glycoprotein without detectable M-protein by conventional analysis--report of a case].

A 56-year-old man gradually developed paresthesia and muscular weakness of the left hand and feet for two years. On admission, neurological examination showed predominantly sensory polyneuropathy. Electrophysiological study and sural nerve biopsy demonstrated segmental demyelination, but any underlying congenital, toxic, metabolic or neoplastic cause was failed to reveal. The serum IgM level was 576 mg/dl, while IgG and IgA were normal. An immunoblot analysis and ELISA showed serum IgM antibody that reacted with human MAG. Serum IgM M-protein, however, was detectable not by conventional serum protein electrophoresis and immunoelectrophoresis, but by immunofixation. Anti-MAG antibodies should be evaluated in the patients with slowly progressive demyelinating polyneuropathy of unknown etiology, even if no serum M-protein is detected by conventional methods. Serum M-protein may play a role of pathogenesis of demyelination, and immunofixation method could be beneficial to detect small amount of M-protein.

Autoantibodies↗
PubMed1993

Investigations of the run and the attachment of the lateral pterygoid muscle in Japanese.

Studies of the run and the attachment of the lateral pterygoid muscle were made on 79 samples from 41 cadavers in the collection of the Department of Anatomy of the Tokyo Dental College. Origin shapes were classified into 3 types: type I, in which there is a clear boundary between the muscle venter adhesion for the upper muscle venter and the lower muscle venter; type II, where the boundary between them is unclear; and type III, where the difference between the two cannot be distinguished at all. When this classification was applied to the specimens, all 21 of the 1-venter specimens fell into type III; 37 (69.8%) of the 2-venter specimens fell into type I; 10 (18.9%) of the 2-venter specimens fell into type II, and 6 (11.3%) of the 2-venter specimens fell into type III. All 5 of the 3-venter specimens were type II. From the results of this studies, we saw that, regardless of which investigation method was employed, the number of venter runs and the origin configuration did not correlate at all.

Asian People↗
PubMed1993

Rat liver nuclear receptors for thyroid hormone: binding characteristics after stabilization and storage.

Conditions for both stabilization and storage of rat liver nuclear receptors for thyroid hormone for up to 28 days were determined using agents that might protect the receptor from spontaneous degradation. Without any protective agent a statistically significant (P < 0.05) diminution of 3,5,3'-triiodothyronine (T3) binding occurred at 0 degree C within 14 days. Dithiothreitol can maintain the initial T3 maximum binding capacity (MBC) for up to 7 days at 0 degree C. The compounds tested, including spermine, sodium molybdate, thioglycerol, and nitrogen gas, had no stabilization effect on nuclear receptors. A statistically significant (P < 0.05) stabilization for up to 28 days at 0 degree C of the initial MBC of T3 receptors was observed in the presence of 0.2 mol.l-1 phosphate anion or 20% (w/w) glycerol. The protective effect of phosphate anion was due to the phosphate ion itself rather than to the high ionic strength.

Animals↗
PubMed1993

[Skin reaction(s) to culture supernatant(s) from Dermatophagoides farinae (Df)-stimulated lymphocytes, and their correlation with Df-induced interleukin 2 responsiveness by lymphocytes from patients with bronchial asthma].

To investigate the inflammatory function of Dermatophagoides farinae (Df)-activated lymphocytes, supernatants from cultures of the lymphocytes were intracutaneously injected into donors' forearms. Injection of the supernatants of Df-stimulated lymphocytes from mite-sensitized atopic individuals with such diseases as bronchial asthma induced a profound inflammatory reaction in the autologous skin, characterized by erythema extending more than 15 mm in mean diameter and edema. The inflammation was at its peak after approximately 20 min, which was followed by gradually re-growing erythema lasting for as long as 24 hours after injection. Supernatants of unstimulated lymphocytes were also capable of inducing the same reaction, indicating the presence of in vivo activated lymphocytes, although the extent of the response was always smaller. The induced response in normal individuals was erythema of less than 15 mm in mean diameter. The supernatants obtained from cultures at 4 degrees C failed to induce such inflammation. The culture supernatants of ovalbumin-restimulated lymphocytes were also incapable of augmenting the response. The combined data show that the production of inflammatory response-inducing factor(s) from Df-stimulated lymphocytes was antigen specific. Significant skin reactions was correlated with the IL2 responsiveness of Df-stimulated lymphocytes. The skin reaction induced by factor(s) derived from Df-stimulated lymphocytes, which might be similar to the bronchial hyperreactivity of patients with bronchial asthma. The in vitro assay for Df-induced IL2 responsiveness by lymphocytes might reflect the in vitro immediate, late and/or delayed type hypersensitivity.

Animals↗
PubMed1993

[The anesthetic management of Arnold-Chiari malformation with spinal cord injury].

A rare case of spinal cord injury at C3 level associated with Arnold-Chiari malformation is reported. A 33 year old male was admitted with a complaint of walking difficulty. MRI revealed cerebellar herniation, and a plain X-ray showed spinous process adhesion of C2-3 and slight scoliosis. Percent vital capacity was reduced to 69%, and blood cell count showed a slight anemia. The patient was anesthetized for an orthopedic surgery with pethidine 70 mg, thiamylal 200 mg, 60% nitrous oxide, 40% oxide, and 0.5-1.2% isoflurane. There was a mild decrease in arterial blood pressure during surgical procedures, but this could be easily treated by fluid therapy, and there was no episode of autonomic hyperreflexia. Postoperative course of the patient was uneventful, except a transient pneumonia and urinary tract infection. The key in the anesthetic management of Arnold-Chiari malformation with spinal cord injury is the control of intracranial pressure, care for respiratory dysfunction and the prevention of infection as well as autonomic hyperreflexia.

Adult↗
PubMed1992

Anticardiolipin antibodies in NZW x BXSB F1 mice. A model of antiphospholipid syndrome.

NZW x BXSB F1 (W/B F1) male mice develop systemic lupus-like disease, and several autoantibodies, circulating immune complexes, and lupus nephritis become apparent. The abnormally high incidence of degenerative coronary vascular disease with myocardial infarction and thrombocytopenia due to the presence of both platelet-associated antibodies and circulating antiplatelet antibodies in this animal has been reported. We found that W/B F1 male mice produced autoantibodies against cardiolipin (aCL) and that the titer of aCL increases with age. aCL from W/B F1 male mice were mainly IgG and binding activity to cardiolipin was aCL-cofactor (beta 2-glycoprotein I (beta 2-GPI)) dependent. We developed monoclonal aCL from these animals and examined specificity of the autoantibodies. All the mAb used reacted with the negatively charged phospholipids, cardiolipin, phosphatidylserine, and phosphatidylinositol, and some reacted with platelets and DNA. The addition of human or mouse beta 2-GPI enhanced the titer for monoclonal aCL from the W/B F1 mice. From the results of competitive inhibition enzyme immunoassay with monoclonal aCL and purified beta 2-GPI, aCL from the W/B F1 mice recognized the complex of CL and beta 2-GPI. The W/B F1 male mouse may be an appropriate model for use in studies on the pathologic significance of aCL in patients with antiphospholipid syndrome.

Animals↗
PubMed1992

Heterogeneity of anticardiolipin antibodies defined by the anticardiolipin cofactor.

Anticardiolipin antibodies (aCL) found in sera from patients with SLE react with cardiolipin (CL) in the presence of a 50-kDa serum cofactor. The cofactor, which was identified to be beta 2-glycoprotein I by sequencing the N-terminal amino acids, not only enhances CL binding by antibodies in SLE but also depresses it by antibodies associated with syphilis. Cofactor-dependent binding of aCL in SLE to solid phase CL was competitively inhibited by the simultaneous addition of fluid phase CL but was unaffected by either prior or simultaneous addition of a high excess of the cofactor. Binding of aCL in syphilis to solid phase CL was competitively inhibited by either addition of the cofactor or fluid phase CL. aCL in SLE reacted with CL, PS, and PA in the presence of cofactor. In contrast, biotinyl-cofactor bound directly to these anionic phospholipids (PL) and also to PG. These results show that the cofactor-CL complex bears an epitope that confers recognition specificity for aCL in SLE, in contrast with direct CL recognition by syphilitic aCL. The direct binding of the cofactor to PL suggests that the cofactor dependence of aCL binding to PL is due to recognition by aCL of a unique epitope generated upon the formation of the cofactor-CL complex.

Amino Acid Sequence↗