Search PubMed⌕ Search

Biomedical subjects

M Nishikawa

Publications and source records attributed to M Nishikawa.

At least 469 records · Page 26Linked to original sources
PubMed1993

Down-regulation by retinoic acid of the catalytic subunit of protein phosphatase type 2A during granulocytic differentiation of HL-60 cells.

Activity of protein phosphatase measured in the absence of divalent cations was decreased by 50% during all-trans retinoic acid (ATRA)-induced HL-60 cell differentiation into the granulocytic phenotype. Treatment of HL-60 cells with ATRA led to a dramatic decrease in the amount of protein phosphatase type 2A (PP2A) protein, whereas that of protein phosphatase type 1 (PP1) protein was relatively constant, as detected by immunoblotting with antibodies specific to PP1 and PP2A. The decreased phosphatase activity may be mainly due to a decrease in the expression of the PP2A protein. The mRNA level of PP2A beta was markedly decreased within 5 h after addition of ATRA, but there was only a slight increase in the mRNA level of PP2A alpha. Selective down-regulation of PP2A beta mRNA clearly preceded the cell differentiation induced by ATRA treatment. Thus, PP2A is down-regulated during ATRA-induced differentiation of HL-60 cells into granulocytes.

Cell Differentiation↗
PubMed1993

Immunoaffinity purification and characterization of gamma-aminobutyric acid (GABA)B receptor from bovine cerebral cortex.

We developed a novel method for immunoaffinity purification of gamma-aminobutyric acid (GABAB) receptor from bovine cerebral cortex using a monoclonal antibody, which specifically recognizes an 80-kDa GABA-binding protein (Nakayasu, H., Mizutani, H., Hanai, K., Kimura, H., and Kuriyama, K. (1992) Biochem. Biophys. Res. Commun. 182, 722-726). The GABA binding activity in the solubilized synaptic membrane preparation was adsorbed on the antibody-conjugated beads and was eluted as a single protein band of 80 kDa by an acidic buffer, pH 2.5. The purified preparation mimicked the GABAB receptor in its binding activity for GABA, baclofen (GABAB receptor agonist) and 2-hydroxysaclofen (a GABAB receptor antagonist). The purified preparation was reconstituted with partially purified GTP-binding protein and an adenylylcyclase preparation on a phospholipid membrane. On addition of GABA or baclofen to the reconstituted membrane, the adenylylcyclase activity was inhibited, and this inhibition was antagonized by 2-hydroxysaclofen. Moreover, this inhibition by GABA was not observed in a system reconstituted system without either the 80-kDa GABA-binding protein or the GTP-binding protein. These results are strong evidence that the 80-kDa antigenic protein is the GABAB receptor. This is the first report of the nearly complete purification of the GABAB receptor.

Adenylyl Cyclases↗
PubMed1993

Changes in hematopoiesis-supporting ability of C3H10T1/2 mouse embryo fibroblasts during differentiation.

To investigate the functional change of stromal cells along with differentiation, we used a differentiation-inducible mouse embryo fibroblast cell line, C3H10T1/2 (10T1/2). Stably determined preadipocyte and myoblast cell lines were established after a brief exposure of 10T1/2 cells to 5-azacytidine. These cell lines terminally differentiated into adipocytes and myotubes, respectively, under appropriate conditions. The hematopoiesis-supporting ability of each 10T1/2-derived cell line was examined by coculture with FACS-sorted murine hematopoietic stem cells (Thy-1lo c-kit+ Lin-). The number of granulocyte-macrophage progenitors (CFU-GM) was slightly reduced after 7 days of culture with parent 10T1/2 fibroblasts, whereas a marked increase in CFU-GM number was observed when the cells were cultured on preadipocytes. Mature adipocytes and myogenically determined cell lines, on the other hand, did not support CFU-GM growth. Further, Northern analysis showed that the preadipocyte cell line acquired the ability to produce a significant amount of stem cell factor (SCF), interleukin-6 (IL-6), leukemia inhibitory factor, and macrophage colony-stimulating factor mRNAs in response to IL-1 or lipopolysaccharide stimulation. Terminal adipocytic differentiation resulted in reduced ability to express these cytokine mRNAs. Similarly, highest IL-6 activity was detected in the supernatant of preadipocyte culture, whereas adipocytes did not secrete IL-6 even after IL-1 stimulation. Interestingly, hematopoiesis-nonsupporting myoblasts and myotubes also expressed abundant SCF mRNA, suggesting that SCF, per se, may not be sufficient for stem cell growth and survival. The 10T1/2-derived cell lines could provide a valuable tool to aid in the analysis of stromal cell development and the search for novel stromal factors.

Adipose Tissue↗
PubMed1993

[Thyroid hormone metabolism].

Most thyroxine (T4) secreted from the thyroid is deiodinated in peripheral tissues. At least three isozymes are known in iodothyronine deiodinase which catalyzes the conversion of T4 to triiodothyronine (T3) or reverse T3. Type I 5'-deiodinase (5'D-I) exists in most tissues including the liver, kidney and thyroid. Type II 5'-deiodinase (5'D-II) which exists mainly in the brain, pituitary, brown fat and placenta plays an important role in the saturation of intracellular T3 receptor. Type III enzyme (D-III) which deiodinases the five positions of T3 is considered to modulate the T3 content by regulating its degradation. The complementary DNA (cDNA) for the rat and human 5'D-I has recently been cloned. 5'D-I contains a rare amino acid selenocysteine, which is essential for normal deiodinative function in humans as well as rats. On the other hand, 5'D-II, whose molecular weight is much heavier than that of 5'D-I, does not contain selenocysteine and its cDNA has not been sequenced. Little is known about the molecular characteristics of D-III. Further studies are needed to clarify the molecular mechanism by which deiodinase proteins are produced in various circumstances and to investigate the meticulous aspects of metabolic pathways other than deiodination.

Adipose Tissue, Brown↗
PubMed1993

Congenital subclavian steal syndrome with anomaly of the aortic arch.

A case of congenital subclavian steal syndrome associated with an anomalous right-sided aorta is reported. A 41-year-old man complaining of vertigo and a loss of consciousness was admitted. Physical examination revealed a blood pressure differential between the arms that was 20 mm Hg less in the left. Aortography showed a right aortic arch from which arose the right subclavian and both common carotid arteries. The left subclavian artery did not opacify. Right vertebral angiography showed retrograde filling of the left vertebral. A left carotid-subclavian bypass was performed. Postoperatively, the patient is symptom free with equalized blood pressure.

Abnormalities, Multiple↗
PubMed1993

Sustained c-kit expression in a human erythroleukemia cell line (HEL) after megakaryocytic differentiation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA).

Changes in c-kit proto-oncogene expression were examined in a human erythroleukemia cell line, HEL, during 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced megakaryocytic differentiation. When HEL cells were treated with 10(-7) M TPA, glycophorin A expression and hemoglobin synthesis were reduced, while the expression of GP IIb/IIIa was induced in association with the morphological changes. Northern blot analysis showed that, during this megakaryocytic differentiation of HEL cells, c-kit mRNA expression persisted even after there was an apparent reduction in c-myc mRNA. This finding supports the idea that the expression of c-kit, a marker of primitive hematopoietic progenitors, may persist along with differentiation toward a megakaryocytic lineage.

Base Sequence↗
PubMed1993

Synthesis and pharmacokinetics of a new liver-specific carrier, glycosylated carboxymethyl-dextran, and its application to drug targeting.

To develop a new carrier system for hepatic targeting, carboxymethyl-dextran (CMD) was modified with galactose and mannose residues (Gal-CMD, Man-CMD), and their disposition characteristics were studied in mice using 14C-labeled dextran. At a dose of 1 mg/kg, i.v.-injected Gal-CMD and Man-CMD rapidly accumulated in the liver parenchymal and nonparenchymal cells, respectively, because of their preferential uptake via carbohydrate receptors in these cells. Pharmacokinetic analysis revealed that their uptake rates were sufficiently large for selective drug targeting. Targeting of cytosine beta-D-arabinoside (araC) was studied using Gal-CMD as a specific carrier to the hepatocytes. From the conjugate of araC with Gal-CMD, araC was released with a half-life of 36 hr in phosphate buffer (pH 7.4) and 23 hr in plasma. An in vivo biodistribution study demonstrated a disposition profile of the conjugated araC similar to that of the carrier, and selective delivery to hepatocytes of up to 80% of the dose was achieved. These findings suggest that glycosylated CMDs are carriers with a high affinity to liver parenchymal or nonparenchymal cells without any affinity to other tissues.

Animals↗
PubMed1993

Zollinger-Ellison syndrome and pheochromocytoma. Report of a case.

A 49-year-old woman was diagnosed in 1985 as having pheochromocytoma because of hypertension with high levels of plasma catecholamine concentration and 24-hour urine excretion of vanillyl-mandelic acid and metanephrine together with a right adrenal mass. The excised tumor cells had fine granular basophilic cytoplasm with argyrophilic granules by Grimelius' method. Four years later, she was diagnosed as having a duodenal bulb ulcer. Serum gastrin showed an abnormally high level of 1900 pg/ml. Abdominal echogram and computed tomography revealed a hypoechoic lesion in the pancreas and intrahepatic multiple tumors. A needle biopsy specimen of the liver tumor was compatible with the histology of metastatic islet cell tumor. A diagnosis of Zollinger-Ellison syndrome was made due to malignant gastrinoma with multiple liver metastases. The patient had no family history of endocrinological or neoplastic disorders. The present case indicates the possibility that pheochromocytoma and gastrinoma, that is, endocrine tumors characteristic of multiple endocrine neoplasia (MEN) I and MEN II, may be coincident even in a person without MEN. A continued awareness of previously rare or undescribed manifestations is important in patients with islet cell tumors or pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1993

Sulphated bile acid per se inhibits colonic carcinogenesis in mice.

Peroral sulpholithocholic acid (SLC) promoted colonic tumorigenesis in conventional rats. We then tested this compound in the mouse, a species with different bile acid metabolism from the rat. Female conventional ICR mice received 0.5 mg of N-methyl-N-nitrosourea (MNU) three times in one week intrarectally or 16 mg/kg body weight of 1,2-dimethylhydrazine (DMH) subcutaneously once a week for 10 weeks, followed by a basal diet (CE-2), or CE-2 containing SLC or lithocholic acid (LC) (both at 0.5 mmol/100 g CE-2) for 40 weeks. At autopsy, numbers of mice bearing colonic neoplasms were 4/26 (15%) in the MNU + CE-2, 4/23 (17%) in the MNU + SLC, 5/28 (18%) in the MNU + LC, 12/24 (50%) in the DMH + CE-2, 6/23 (26%) in the DMH + SLC and 11/27 (41%) in the DMH + LC group. The DMH + SLC group had less adenocarcinomas than did the DMH + CE-2 and the DMH + LC group (P < 0.05). Total faecal bile acids in the mice fed on bile salts showed threefold increases compared with those on the basal diet. Sulphates constituted an average 7% and 19% of faecal bile acids in the MNU + SLC and DMH + SLC group, respectively. These results indicated that effects of peroral SLC on colonic carcinogenesis correlated with the degree of desulphation of SLC in the intestine and sulphates per se inhibited colonic carcinogenesis.

1,2-Dimethylhydrazine↗
PubMed1993

Primary liposarcoma of the omentum.

This report is of a 54 year old female with omental liposarcoma. Diagnosis was made by ultrasonography, computed tomography, angiography and operation. The patient was treated by surgical excision. The histological examination revealed that the tumour was round cell liposarcoma. This is the first report to our knowledge of round cell liposarcoma of the omentum.

Angiography↗
PubMed1993

Familial unresponsiveness to thyrotropin by autosomal recessive inheritance.

Unresponsiveness to TSH has been identified and sufficiently studied in only three patients. We report siblings with this defect as the first documentation of familial occurrence. A 26-yr-old woman was diagnosed with congenital hypothyroidism during infancy. The thyroid was atrophic, and thyroid function tests without T4 replacement showed serum free T4 levels below 3 pmol/L, serum TSH of 125 mU/L, and serum thyroglobulin below 5 mg/L. 123I scintigram showed decreased uptake (5% at 24 h), but normal shape at the correct position in the neck. Autoantibodies against thyroglobulin, thyroid peroxidase, and TSH receptor in serum were not detected. The amount of cAMP released into FRTL-5 cell culture in the presence of TSH from the patient was not different from that released by the same amount of TSH from normal subjects, suggesting that TSH bioactivity in our patient was normal. The brother of the patient also had congenital hypothyroidism, and the data on his thyroid function was similar to that for his sister. There was a consanguineous marriage in the parents of the siblings, and the mother of the patients had a normal serum free T4 level, but slightly increased serum TSH and thyroglobulin levels, indicating subclinical hypothyroidism. The possible pathogenesis of TSH unresponsiveness in our patients includes a mutation in the TSH receptor gene, abnormality in transcription-regulating factor, abnormality in GTP-binding protein, and/or inhibition of the action of cAMP. The family history of the patients suggests that the mode of inheritance in TSH unresponsiveness is autosomal recessive.

Adult↗
PubMed1993

Measurement of erythrocyte Na,K-ATPase activity in normal pregnant women.

To investigate the peripheral metabolic status during normal pregnancy, we measured the number of erythrocyte Na,K-ATPase units as well as the cation transport activity of the pump from 32 normal pregnant women and 12 normal controls. The number of pump units determined by maximal ouabain binding to erythrocyte in normal pregnancy was significantly higher than that in normal controls (mean +/- SEM: 0.52 +/- 0.03 vs. 0.39 +/- 0.04 pmol/10(9)RBC, P < 0.05). The total cation transport activity of the pump measured by 86Rb uptake also significantly increased during pregnancy (98.9 +/- 6.4 vs. 73.1 +/- 5.4 nmol/10(9) RBC, P < 0.01). However, the mean cation transport activity per pump unit, which was presumed to be an indicator of the peripheral metabolic status, was unchanged in any of three trimesters when compared with that in normal controls. Serum FT4 levels measured by two different methods were significantly lower in the third trimester than in the first trimester (P < 0.01). In conclusion, erythrocyte Na, K-ATPase activity per pump unit is normal in pregnant women, suggesting that the peripheral metabolic status in pregnancy seems to be normal. Increases in both the number and function of the pump may be influenced by factors other than thyroid function.

Adult↗
PubMed1993

Changes in plasma atrial natriuretic peptide during hemodialysis: mechanism of elevated levels in patients with chronic renal failure.

An elevated plasma atrial natriuretic peptide (ANP) concentration was observed in patients with chronic renal failure, and it was significantly (P < 0.01) decreased by hemodialysis with or without fluid removal. The ANP concentration was decreased by dialysis without fluid removal and the decrease was significantly (P < 0.01) correlated with the pre-dialysis value. The decrease in this peptide during fluid removal without diffusion was significantly (P < 0.05) correlated with the decrease in the circulating plasma volume measured by dye dilution. The decrease in the ANP level was therefore considered to be related to a fall in right atrial pressure caused by the decline in the circulating plasma volume. The circulating plasma volume, osmotic pressure, and blood pressure were not changed by hemodialysis without fluid removal. Moreover, the filtrate concentration of ANP (mean: 5.5 pg/ml) during fluid removal without dialysis was only about 8% of the plasma level, so filtration of ANP from the dialyzer was negligible. The decrease in ANP during hemodialysis without fluid removal may therefore have been caused by the removal of or a change in the level of substances, for example electrolytes, epinephrine, and uremic toxins. In addition to volume expansion, such a substance(s) might influence plasma ANP levels in patients with chronic renal failure.

Adult↗
PubMed1993

Evaluation of peripheral metabolic status by determination of Na-K ATPase pump activity in circulating erythrocytes in patients with thyroid diseases and nonthyroidal illnesses.

The number of Na-K ATPase units in erythrocytes (RBC) was determined by the maximal ouabain binding assay in 25 normal subjects and patients with hyperthyroidism (n = 29), hypothyroidism (8), chronic renal failure (CRF, 19) and with neoplastic disorders (NP, 12). The activity of the pump units was also assessed by measuring ouabain-sensitive 86Rb uptake in some of these subjects. In addition, it was determined in mononuclear cells in normal controls and patients with hyper- and hypothyroidism and CRF. Significant diminution of the number of the RBC pump units was found in hyperthyroidism, while it was increased in hypothyroidism. The binding (O) of old RBC was significantly lower than that (Y) of young RBC and a striking correlation was observed between the % reduction rate ((Y-O)/Y) of the binding and the serum T4 level in hyperthyroidism (r = 0.85, P < 0.02). No difference was observed in pump units of mononuclear cells in normal and hyper- and hypothyroidism. It is suggested that the thyroid hormone- mediated disappearance of the pump units in RBC may play a role in reducing the number of pump units in RBC in hyperthyroidism. The ratio of RBC 86Rb uptake to the number of the pump units in the same cell (U/B) bore a significant relation to serum T3 (r = 0.48, P < 0.05) and T4 (r = 0.49, P < 0.05) indicating that the U/B is a useful index for the peripheral metabolic status. In CRF patients with low T3 levels, bindings were increased but those in NP with low T3 was almost normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Temperature Regulation↗
PubMed1993

Correlation of orbital muscle changes evaluated by magnetic resonance imaging and thyroid-stimulating antibody in patients with Graves' ophthalmopathy.

To evaluate the relationship between eye changes and autoantibody to the thyrotropin receptor in patients with Graves' disease, we evaluated the eye changes using magnetic resonance imaging and the results were correlated with thyroid-stimulating antibody, thyrotropin binding inhibitor immunoglobulin and thyroid growth activity. Subjects were 15 patients with Graves' disease who had Graves' ophthalmopathy, including exophthalmos and other signs and symptoms, and nine patients without ophthalmopathy; all were maintained in a euthyroid state by antithyroid drugs. The thyrotropin-binding inhibitor immunoglobulin was measured by a kit, and thyroid-stimulating antibody and thyroid growth activity were evaluated by cyclic adenosine 3',5'-monophosphate production and [3H]thymidine incorporation, respectively, by cultured functional rat thyroid lined cells. The sum of the swelling ratios (muscle thickness to the diameter of the optic nerve) of the four extraocular muscles correlated well with the degree of exophthalmos. The thyrotropin-binding inhibitor immunoglobulin was positive in nine out of 15 patients with ophthalmopathy; however, no correlation was observed between the activity and exophthalmos or muscle swelling. No significant correlation was observed between muscle changes and thyroid growth activity either. On the other hand, thyroid-stimulating antibody (642 +/- 91%) in Graves' patients with ophthalmopathy was significantly (p < 0.02) higher than that (315 +/- 84%) in patients without ophthalmopathy. Moreover, the level of stimulating activity in Graves' patients with ophthalmopathy showed a significant (p < 0.02) positive correlation with the sum of the swelling ratios of the individual eight eye muscles. These results suggest that thyroid-stimulating antibody has a close relation to Graves' ophthalmopathy.

Adolescent↗