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Biomedical subjects

A Kuroiwa

Publications and source records attributed to A Kuroiwa.

At least 19 recordsLinked to original sources
PubMed1992

Reduction and inactivation of the sarcoplasmic Ca(2+)-ATPase by 2-mercaptoethanol--contrast to the (Na+,K+) ATPase.

The sarcoplasmic Ca(2+)-ATPase was reduced with 300 mM 2-mercaptoethanol at elevated temperatures (40-45 degrees C) with a concomitant loss of ATPase activity. The reduction and inactivation of the Ca(2+)-ATPase proceeded rapidly in the absence of Ca2+. The Ca(2+)-ATPase was also inactivated with 2-mercaptoethanol in the presence of diluted SDS (0.4 mg/ml) even at 20 degrees C. In contrast to the (Na+, K+) ATPase, the inactivated Ca(2+)-ATPase in the presence of diluted SDS was sedimented by the centrifugation at 100,000 x g for 30 min.

Animals↗
PubMed1992

[Studies on purine-pyrimidine metabolism (1)--Quantitation of purine-pyrimidine metabolites and allopurinol-oxipurinol in biological fluids].

A reversed-phase high-performance liquid-chromatography method for determining simultaneous quantitation of purine-pyrimidine metabolites, allopurinol and oxipurinol in plasma and urine samples was studied. Separation was optimal with phosphate buffer (10 mmol/l, pH 5.0) containing 1% methanol as an eluent and mu Bondapak C18 as a column. An isocratic separation of a standard mixture of 13 compounds was achieved within 40 minutes with adequate reproducibilities (coefficient of variation: 2.49% for 1.63 mumol/l orotidin-0.12% for 50 mumol/l uridine). A simple ultrafiltration of plasma yielded quantitative recoveries (uric acid: 101.7-107.5%, hypoxanthine: 90.4-102.8%, xanthine: 95.9-99.5%, oxipurinol: 104.4-107.1%, allopurinol: 97.4-103.4%). Compounds were identified by their retention times, absorbance ratios, co-elution with standards and enzymic shifts. In addition to the above compounds, simultaneous quantitation of pseudouridine, uridine, adenine and inosine in the plasma would be possible under the same conditions.

Allopurinol↗
PubMed1992

Neuroectodermal autonomy of Hox-2.9 expression revealed by rhombomere transpositions.

Involvement of the Hox genes in regional specifications of the vertebrate body axis is suggested by sequence similarity with the homeotic selector genes of Drosophila, the conservation of a collinear relationship between genomic organization and site of expression, and mutational analysis. Subdivision of vertebrate embryo hindbrain neuroepithelium into lineage compartments (rhombomeres) underlies segmental patterning of neuronal differentiation. The rhombomere boundaries delimit domains of expression of Hox genes, presumed to be determinants of rhombomere phenotype, suggesting that Hox genes confer positional value; the formation of rhombomere 4 (r4) is followed by strong expression of Hox-2.9 within its confines. If the Hox genes are determinants, their expression should be autonomous from the developmental stage at which regional commitment becomes fixed and irreversible. We have transplanted the future r4 region (from state-9-chick embryos) into the more anterior position of r2 and probed for Hox-2.9 transcripts. We report here that Hox-2.9 was expressed in the ectopic r4 as strongly as in the normal r4, whereas reciprocal grafts of future r2 to r4 position did not express Hox-2.9. The phenotype of ectopic rhombomeres developed according to their original position, as demonstrated by retrograde tracing of efferent cranial nerve nuclei. As early as stage-9-(six somites), both Hox-2.9 expression and segment identity are autonomous in the chick embryo hindbrain, independent both of position in the neuroepithelium and of signals from the underlying mesoderm.

Animals↗
PubMed1992

Cell type dependent transcription regulation by chick homeodomain proteins.

Five chick homeodomain proteins (CHOXs), CHOX-1.7, -1.1, -1.4, -4.2 and -2.6, had different transcription-regulating activities in a chick cultured cell line, LMH. In particular, CHOX-1.7 highly activated transcription when NP6 was used as the target site whereas CHOX-1.4 did not. This was mainly due to differences in the activation domains since both proteins bound to NP with almost the same affinities in vitro. In LMH cells, they competitively acted on target gene transcription. Moreover, the strength of the CHOX-1.4 activation domain depended on the cell type. These findings suggest that the effect on a target gene is determined by a combination of CHOXs and cell types.

Amino Acid Sequence↗
PubMed1992

Comparison of Ki-ras gene mutation among simultaneously occurring multiple urethan-induced lung tumors in individual mice.

Mouse lung tumors were induced in C57BL/6J(female) x A/J(male) F1 mice by a single s.c. injection of urethan. About 6 months later, multiple small-sized lung tumors were detectable in almost all mice. After a further 6 months, some of these tumors became larger than the rest. We examined whether there were any mutational differences among multiple lung tumors in a single mouse. Direct DNA sequencing of a separately amplified Ki-ras gene by polymerase chain reaction (PCR) was carried out with 25 DNA samples from multiple tumors in four mice. Twenty-four of 25 tumors (96%) had mutations at the codon 61 of the Ki-ras gene. The major mutations involved were either AT to GC transition (44%) or AT to TA transversion (44%) at the second base of codon 61. We compared the types of these gene mutations among the tumors from each of two mice from two different groups of siblings and then compared the two groups. Interestingly, in the first group of siblings, we detected CTA in 5/6 tumors in the first mouse and again CTA in 4/6 tumors in the second one. In the second group of siblings, we detected CGA in 5/7 tumors in one mouse and CGA again in 3/5 tumors in the second mouse. These results show that the pattern of Ki-ras codon 61 mutations in urethan-induced lung tumors is similar in tumors developing in siblings, suggesting that host factors have an effect on the carcinogen-induced mutational pattern. There was no major mutational difference between small and large tumors. The results suggested that other event(s) in addition to the mutation of the Ki-ras gene might play a role during the development of large-sized tumors.

Amino Acid Sequence↗
PubMed1992

Guinea pig model of immunologic asthma induced by inhalation of trimellitic anhydride.

We established a model of asthma induced by trimellitic anhydride (TMA) in guinea pigs and assessed the role of sensitization in the development of their bronchial hyperresponsiveness, and relationship between bronchial responsiveness and bronchial inflammation. Fourteen guinea pigs (sensitized group) were administered 1 mg/0.5 ml of trimellity 36-bovine serum albumin intramuscularly and 0.5 ml of complete Freund adjuvant on Day 1 as the priming dose. Booster doses were repeated on Day 15. By Day 28, all of the sensitized animals showed a high passive hemagglutination titer against trimellityl 14-ovalbumin. On Day 29, they were challenged by an inhalation of TMA (150 mg/m3) for 30 min, and respiratory resistance (Rrs) was monitored by the oscillation method. In all sensitized animals, Rrs increased immediately upon challenge and returned to baseline within 6 h. The bronchial reactivity to acetylcholine (Ach), measured 6 h after TMA challenge in the sensitized animals, increased significantly (p < 0.01) compared with that measured 24 h before challenge; that measured 24 h later was not different from that before challenge. There was also a significant difference (p < 0.01) in the number of eosinophils in the lamina propria and the epithelium 6 and 24 h after the challenge inhalation in the sensitized group. The increased airway responsiveness to Ach in the sensitized animals was correlated with an increase in the number of eosinophils in the lamina propria and the epithelium. These observations suggest that humoral antibody and eosinophils are involved in the pathogenesis of TMA-induced asthma.

Acetylcholine↗
PubMed1992

Identification of type I collagen-producing cells in human gastrointestinal carcinomas by non-radioactive in situ hybridization and immunoelectron microscopy.

Invasive growth of cancer cells induces desmoplastic reaction as one of the host reactions. It has been a matter of controversy whether stromal collagen is produced by cancer cells or stromal fibroblasts. In the present study, we investigated the cellular origin of Type I collagen in human gastrointestinal carcinomas by in situ hybridization and immunoelectron microscopy. In situ hybridization technique with digoxigenin-labeled RNA probes revealed that spindle-shaped fibroblasts in the stromal area were abundantly positive for transcripts of pro alpha 1(I) collagen in intestinal-type adenocarcinoma. Gland-forming carcinoma cells were negative. In diffuse-type carcinoma of the stomach, spindle-shaped or stellate fibroblasts were positive, whereas dissociated, oval carcinoma cells were negative. A precise determination of cell type was done by immunoelectron microscopy. Intracellular immunoreactivity for Type I collagen was observed in rough endoplasmic reticulum of fibroblasts (including myofibroblasts) in the stromal area. No definite reactivity was obtained in cancer cells by either in situ hybridization or immunoelectron microscopy. Our results indicated that stromal Type I collagen is produced by stromal fibroblasts, which are activated by cancer invasion.

Adenocarcinoma↗
PubMed1992

Electrophysiologic changes before onset of ventricular tachyarrhythmias during partial reperfusion following severe myocardial ischemia in dogs.

We examined the electrophysiologic changes before an onset of ventricular tachyarrhythmia during partial reperfusion following severe myocardial ischemia. The left anterior descending coronary artery was occluded and cannulated below the occluded portion in 26 dogs. To deplete collateral flow into the ischemic myocardium, retrograde blood flow was induced for 20 min. Then, in all dogs except 7 with ventricular fibrillation during retrograde blood flow, partial reperfusion through collateral flow into the ischemic myocardium was produced by stopping the retrograde flow. Within 2 min of partial reperfusion, sustained ventricular tachycardia (VT) occurred in 7 dogs (group A) and non-sustained VT degenerating ventricular fibrillation occurred in 11 dogs (group B) of the remaining 12 dogs. In 6 dogs of group A and 9 of group B, epicardial conduction block appeared 5.0 +/- 2.2 and 3.5 +/- 1.3 min after ischemia. This was followed by fractionated electrical activities 15.2 +/- 3.2 and 11.7 +/- 3.3 min after ischemia. In group A, the fractionation had a slight change in configuration and a small increase in amplitude before the onset of VT during reperfusion; in group B, new deflections with large amplitude emerged before it. There was a significant difference in the amplitude (0.38 +/- 0.2 vs 0.67 +/- 0.3 mV, p < 0.025) between the 2 groups, although there was no significant difference in the amplitude (0.33 +/- 0.2 vs 0.23 +/- 0.1 mV) of the fractionation just before reperfusion. Our results show that slight improvement in fractionation induces sustained VT, and new deflections induce non-sustained VT degenerating ventricular fibrillation, even during partial reperfusion.

Animals↗
PubMed1992

Double atrial response to a single ventricular extrastimulus in a patient with Wolff-Parkinson-White syndrome.

Electrophysiological examination in a 39-year-old male disclosed an accessory pathway between the right atrium and the right ventricle and AV nodal dual pathways. Atrial and ventricular extrastimuli induced paroxysmal supraventricular tachycardia (PSVT), which was shown to be AV reciprocating tachycardia. Double atrial response was noted during ventricular extrastimuli at V1V2 of 280 msec and V1V2 of 250 msec. The first atrial response is considered to have been transmitted in a retrograde fashion in the accessory pathway, and the second atrial response similarly in the slow pathway of the AV node.

Adult↗
PubMed1992

A polyclonal antibody to the rat oestrogen receptor expressed in Escherichia coli: characterization and application to immunohistochemistry.

A rat oestrogen receptor-beta-galactosidase fusion protein was expressed using a pEX2/rat oestrogen receptor cDNA construct. Scatchard analysis of [3H]oestradiol-17 beta binding to the cell lysate revealed that the fusion protein had functional binding sites specific for oestradiol with a dissociation constant of 1.49 nmol/l. The relative molecular weight (M(r)) of the fusion protein was determined as 180,000 by immunoblot analysis of the cell lysate employing a monoclonal antibody to the human oestrogen receptor. The protein was isolated by means of SDS-PAGE and subsequent electroblotting. By immunization with the purified materials on nitrocellulose membrane, a polyclonal antibody to the rat oestrogen receptor was raised in a rabbit. Binding of [3H]oestradiol to the oestrogen receptor from the rat uterus was inhibited by the antibody in a dose-dependent manner. The antibody was also able to recognize the oestrogen receptor occupied by [3H]oestradiol. Thus, the antibody could react with both forms of the receptor molecule, either occupied or unoccupied by the hormone. In immunoblot analysis of the cytosol fraction of the rat uterus, a single band of M(r) 67,000, the size of the oestrogen receptor, was detected by the antibody. Moreover, when the antibody was applied to immunohistochemical examination of paraffin-embedded pituitary and brain sections of the rat, immunostaining was observed in cells of the anterior pituitary and in neurones in specific regions of the brain. The immunoreactivity was restricted exclusively to cell nuclei in both tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A familial case of hereditary angioneurotic edema in Japan.

A 53-year-old man was admitted with impairment of breathing following laryngeal edema. Serum levels of CH50 (22 U/ml), C4 (3 mg/dl), C1-INH protein (10.6 mg/dl) and C1-INH activity (LT 25%) were low. Complement study of the patient's family members revealed that he was one of 5 patients in 3 generations with hereditary angioneurotic edema (HANE). Administration of the androgen derivatives Danazol (600 mg/day) and Oxymetholone (30 mg/day) effectively increased serum levels of C1-INH activity and C4. Though eruption and hepatic dysfunction attributable to administration of the drugs appeared, these side effects improved after withdrawal of the drugs. Subsequently, the treatment with Danazol at a low dose (100 mg/day) was resumed, and the patient has had no episodes of edema for the past 3 years. Regarding the familial cases of HANE, fewer than 20 have been reported in Japan.

Angioedema↗
PubMed1992

Expression and assembly of Torpedo californica (Na,K)ATPase alpha-subunit truncated at N-terminal end in Xenopus oocytes.

cDNAs for mutant alpha-subunits of Torpedo californica (Na,K)ATPase variously truncated at the N-terminal end were constructed and transcribed in vitro. Each of the mRNAs thus synthesized was co-injected into Xenopus oocytes together with mRNA for wild-type beta-subunit. Truncation of the alpha-subunit at trypsin accessible site T2(removal of the N-terminal 36 residues, alpha delta K37) led to a decrease in ouabain-sensitive ATPase activity and ouabain-binding capacity, leaving the amount of immunoprecipitable alpha-subunit unchanged. The Km values for Na+ and K+ of alpha delta K37 were about 10mM and 2mM, respectively, and fall in the same range for the wild-type ATPase. Truncation of the alpha-subunit leaving lysine-54(alpha delta K54) or alanine-79(alpha delta A79) resulted in the loss of the ATPase activity as well as a substantial decrease in the amount of immunoprecipitable alpha-subunit. Since the beta-subunit assembles with and thereby stabilizes the alpha-subunit, which is otherwise degraded rapidly, these results suggest that the segment of the alpha-subunit between lysine-37 and lysine-54 is involved in the assembly with the beta-subunit leading to the formation of the stable and active alpha beta complex.

Animals↗
PubMed1992

[A case of hyperparathyroid bone disease and the review of renal osteodystrophy].

We report here a typical case of hyperparathyroid bone disease associated with CRF on maintenance HD and review on Renal Osteodystrophy. A 39 year-old female patient was admitted because of polyarthralgia and pruritus. She had a history of HD due to CGN for about 13 years. Laboratory data showed an increase in serum PTH and Alkaline phosphatase level. The evidence of osteitis fibrosa was revealed by bone Xp and scintigraphy. Enlarged solid masses were found in her neck by echogram and parathyroid scintigraphy. She was diagnosed as hyperparathyroid bone disease and total parathyroidectomy c autoplantation was done. Shortly after the surgical treatment, subjective symptoms were relieved and PTH level was normalized. The bone Xp findings improved gradually.

Adult↗
PubMed1992

Proteoglycan obtained from bovine aorta suppress thrombin-induced platelet aggregation.

Proteoglycan (PG), isolated and purified from bovine aorta (intima-media), consisted of 68.6% chondroitin 4/6-sulfate (CS 4/6-S), 30% dermatan sulfate (DS), 1.4% heparan sulfate (HS), and a trace of hyaluronic acid (HA). PG did not affect platelet aggregation induced by ADP, collagen, and epinephrine, but inhibited that induced by thrombin. Of the standard GAGs investigated, hyaluronic acid (HA) and CS-4/6-S slightly inhibited only thrombin-induced platelet aggregation. However, PG and standard GAGs did not affect the thrombin induced aggregation of washed platelets. The effect of PG after papain digestion on thrombin-induced platelet aggregation was less potent than that before. It is suggested by the results of this study that PG in the aorta inactivates plasma thrombin, probably by inhibiting thrombin activators or potentiating substances which inactivate thrombin and that these effect of PG would be mainly due to PG-DS and partly due to PG-HS.

Animals↗
PubMed1992

Comparative effects of loop diuretics on AVP-receptor binding and AVP-sensitive adenylate cyclase activity.

The effects of loop diuretics (azosemide, ethacrynic acid and furosemide) on arginine vasopressin (AVP) receptor-adenylate cyclase components were compared in rat renal basolateral membranes. AVP binding was inhibited by these loop diuretics at concentrations above 10(-4) M. At the IC50 of azosemide and ethacrynic acid, the Kd values were significantly increased, while the Bmax values remained unchanged. These findings indicate an inhibitory effect of loop diuretics at high concentrations on the AVP binding to its receptors. Both the basal (AVP-unstimulated) and AVP-stimulated cyclic AMP productions were also inhibited by addition of these drugs. The inhibitions of the AVP binding and AVP-sensitive adenylate cyclase activity were dose-dependent. The above findings suggest that loop diuretics, especially azosemide and ethacrynic acid, can inhibit the basal and AVP-sensitive adenylate cyclase activities directly and also indirectly via the AVP receptor, at least in part. Comparing the loop diuretics, azosemide exerts a similar effect to ethacrynic acid, and they have a more potent antagonistic effect than furosemide with respect to AVP adenylate cyclase activation.

Adenylyl Cyclases↗
PubMed1992

Phenotypic and functional analysis of lamina propria mononuclear cells from colonoscopic biopsy specimens in patients with ulcerative colitis.

Phenotypic and functional analysis was performed with lamina propria mononuclear cells (LPMCs) isolated from colonoscopic biopsies in 27 patients with ulcerative colitis (UC). The proportion of T lymphocytes displaying HLA-DR antigens, interleukin 2 (IL-2) receptor, and transferrin receptor was greater in active UC than in control diseases. When LPMCs were cultured with IL-2 or phytohemagglutinin for 72 h, there were no significant differences in the proportion of cells bearing these activation markers between active UC and controls. The proportion of CD56+ cells and lymphokine-activated killer (LAK) cell activity was lower in LPMCs from active UC than in control cells, and depletion of CD56+ cells from control lamina propria cells essentially eliminated LAK cell activity. Mucosal T lymphocytes may be activated in vivo during active inflammation in UC, and lower levels of intestinal LAK cell activity may be related to the decrease of CD56+ cells under these conditions.

Adolescent↗
PubMed1992

[A case of heterozygous familial hypercholesterolemia showing the regression of coronary atherosclerosis by LDL-apheresis].

A case showing the regression of coronary atherosclerosis by the treatment with LDL-apheresis, was reported. The patient was a 67-year old female with heterozygous familial hypercholesterolemia. She had noticed the xanthelasma or left cubital xanthoma at the age of 50 years old. She was informed about her high serum cholesterol level (greater than 350 mg/dl), and the abnormal thickness of her bilateral achilles tendon at the age of 61 years. As her serum cholesterol level did not decrease sufficiently with several lipid-lowering drugs, she was referred to our hospital in order to obtain treatment for it by LDL-apheresis at the age of 66 years. LDL-apheresis was performed once every two weeks with drugs such as probucol, cholestyramine and pravastatin. Her coronary angiogram after two and half years of LDL-apheresis showed a decrease of the coronary narrowing in segment 1 and segment 13 (from 96.8% to 74.6% in segment 1, and from 81.5% to 61.7% in segment 13, respectively). The thickness of her bilateral achilles tendons had also decreased from 18 mm in the right and 19 mm in the left to 14 mm in both, after receiving LDL-apheresis for two and half years. It is suggested from the result of this case that the regression of coronary atherosclerosis could be expected after treatment with LDL-apheresis in hypercholesterolemic patients.

Aged↗