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Biomedical subjects

K Wada

Publications and source records attributed to K Wada.

At least 613 records · Page 34Linked to original sources
PubMed1990

[Cholecystokinin receptors on guinea pig gastric chief cell membranes].

Cholecystokinin (CCK) binding to its receptors on guinea pig gastric chief cell membranes was characterized with 125I-COOH terminal octapeptide of CCK (125I-CCK8). Specific binding of 125I-CCK8 to chief cell membranes was maximal at pH 6.0 and 30 degrees C after 180 min of incubation and reversible upon the addition of 10(-7) M unlabeled CCK8. CCK analogs such as CCK8, gastrin-I, and COOH-terminal tetrapeptide of CCK (CCK4) competitively inhibited the labeled CCK8 binding with the half maximal inhibitory concentration of 10(-10) M, 3 X 10(-7) M and 10(-6) M, respectively. Furthermore, guanine nucleotide analogs such as GTP gamma S and Gpp(NH)p also inhibited the labeled CCK8 binding to chief cell membranes. Scatchard analysis of the binding data at pH 6.0 revealed two orders of the binding sites and GTP gamma S decreased the binding by converting two binding sites of the receptors to only one site of lower affinity. These results suggest that there are specific receptors for CCK, which are coupled to a guanine nucleotide regulatory protein on guiea pig gastric chief cell membranes.

Animals↗
PubMed1990

[Crystalline glass ceramics model teeth].

The feeling of hardness, stickiness and the rate of cutting during the preparation of a tooth were compared using an extracted tooth, melamine resin and crystalline glass ceramics model tooth (Bioram M) which are used in dental education and practice. Diamond burs were used with an air-turbine handpiece in this experiment. The results indicated that Bioram M had the desirable characteristics of a model tooth and there was a strong resemblance feeling of cutting between Bioram M and a natural vital tooth.

Ceramics↗
PubMed1990

[Studies on titanium casting. (1) Influence of the mold temperature on titanium castings].

Pure titanium and titanium alloys have excellent biocompatibility, excellent corrosion tarnish resistance, a quarter of the specific gravity of gold base alloys and suitable mechanical properties for dental clinical use. However, titanium has some undesirable characteristics. For example, it has a high melting temperature and chemical reactivity at high temperatures. The investigate influence of the mold temperature on castability and mechanical properties of the titanium castings was study. The castability was found to be good at various mold temperatures, but the higher the mold temperature during casting, the greater the adhesive phenomenon between titanium surface and the investment. From the EPMA observation of the surface layer on the titanium castings, an Si- rich layer whose thickness increased considerably with increasing temperature was observed. The Vickers hardness in the surface layer was greater than that in the inner part. At a higher mold temperature during casting the thickness of the high Vickers hardness layer was increased. There was a relationship between the Vickers hardness value and the thickness of Si rich layer. In the tensile strength test of titanium castings, elongation values decrease and tensile strength values increased with the rise in mold temperature.

Dental Alloys↗
PubMed1990

[One-year remission of chronic myelogenous leukemia (CML) after discontinuation of interferon-alpha].

A 53-year-old woman was admitted to our hospital on Nov. 16, 1987, because of general fatigue. On admission, she had hepatosplenomegaly and her peripheral blood profile showed a white blood cell count (WBC) of 309 x 10(3)/microliters with immature neutrophils, a hemoglobin level (Hb) of 7.6 g/dl, platelet count (PLT) of 536 x 10(3)/microliters, neutrophilic alkaline phosphatase (NAP) score of 44. Both Vitamin B12 and LDH levels were high. The bone marrow showed marked myeloid hyperplasia. In a cytogenetic study, Ph1 was found in 3 of 8 metaphases and Ph1 with an additional abnormality of 8 trisomy was noted in 5 of 8 metaphases. She was diagnosed as having chronic myelogenous leukemia (CML) and treated by i.m. injection of interferon (IFN)-alpha at a daily dose of 6 x 10(6) U. Administration of IFN-alpha induced fever for a few days. WBC, PLT count and LDH level gradually decreased, and the NAP score and hepatosplenomegaly improved. She achieved remission in February, 1988. Administration of IFN-alpha was stopped in April, 1988, when the bone marrow showed hypocellularity and normal karyotype. She was treated with 20 mg of prednisolone daily from May until August, because of progressive pancytopenia. She had received no treatment until July, 1989. In May, 1989, the bone marrow again showed myeloid hyperplasia and Ph1 was found in all cells analyzed. Therefore, we resumed IFN-alpha treatment. It is interesting that remission of CML continues for more than one year after discontinuation of IFN-alpha in this case.

Female↗
PubMed1990

[Relationship between years of methamphetamine use and symptoms of methamphetamine psychosis].

The authors researched the demographic characteristics of 233 patients with methamphetamine-associated disorders, and the relation between years of methamphetamine use and symptoms of methamphetamine psychosis. The results were as follows: There were more male users than females. However there were signs that the female users were gradually increasing. Users tended to be older, but users in their 20's and 30's continued to be predominant. Their school careers were usually limited and most of them had left school at a young age. Relations with a particular social group (e.g. organized gangs) has given most of them a chance to use methamphetamine. The symptoms that were seen with high frequency at the first examination were anxiety, fretfulness, auditory hallucination, insomnia, irritability, psychomotor excitement, delusion of persecution, suspicion, delusion of reference, mistake of circumstance, loss of appetite, affective disorder, hypobulia and personality change. With these symptoms, there is a possibility that five years of methamphetamine use is the turning point in terms of the frequency of symptoms occurrence. It was suggested that affective and perceptual disorders depend on the dose of methamphetamine, but abnormalities in thought subject may be deeply influenced by the patient's "feeling of social wrong". Emotional exhilaration and euphoria decreased as the number of years of methamphetamine use increased. These phenomena may be an indication of tolerance. The symptoms that were seen with high frequency at the last examination were hypobulia, affective disorder, personality change, insomnia, anxiety and fretfulness. The symptoms that were highly resistant to treatment were hypobulia, affective disorder, personality change, general malaise, hypochondriasis, insomnia, anxiety and fretfulness. It was suggested that five years of methamphetamine use may be a turning point in the residual rate of symptoms at the last examination after treatment, and also the resistance rate to treatment. Hypobulia and personality change became more evident during treatment.

Adolescent↗
PubMed1990

Myocardial accumulation of iodinated beta-methyl-branched fatty acid analogue, iodine-125-15-(p-iodophenyl)-3-(R,S)methylpentadecanoic acid (BMIPP), in relation to ATP concentration.

To clarify the relationship between the myocardial accumulation of 125I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) and intracellular adenosine-5'-triphosphate (ATP) content, the effect of 2,4-dinitrophenol (DNP, an electron transport uncoupler) on myocardial BMIPP accumulation was studied, in comparison with that of thallium-201-chloride (201Tl-Cl). In the mouse myocardium, DNP decreased the intracellular ATP and ADP levels, without affecting either acyl-CoA synthetase activity or the level of CoA-SH. Following treatment with DNP, decreases in myocardial BMIPP accumulation correlated well with those of ATP, while 201Tl-Cl showed slightly increased accumulation in the myocardium. Thus, in some diseases, BMIPP may be useful in evaluating myocardial ATP levels.

2,4-Dinitrophenol↗
PubMed1990

[Successful bronchial arterial infusion (BAI) of ACNU in the treatment of pulmonary infiltration of acute non-lymphocytic leukemia (ANLL) cells].

A 35-year-old man was admitted to our hospital because of lumbago on March 25, 1988. On admission white blood count was 1,200/microliters with neutrophils of 9% and lymphocytes of 91%, hemoglobin level was 11.2g/dl and platelet count was 55 x 10(3)/microliters. Bone marrow smear showed 77% leukemic cell including non-specific or specific esterase-positive cells. Chest X-rays showed the presence of mediastinal tumor and diffuse reticular shadows. A diagnosis of ANLL was made and a hematological remission was obtained after one course of combination chemotherapy consisting of BH-AC, daunorubicin and prednisolone, but the enlarged mediastinal tumor and pulmonary infiltration worsened rapidly followed by marked dyspnea. This radiographic abnormal shadow was confirmed to be leukemic infiltration from the finding of transbronchial lung biopsy. We hesitated to give systemic chemotherapy because he also had had liver abscess. Accordingly we performed BAI of ACNU at a dosage of 150 mg which led to a dramatic improvement in dyspnea. 60Co therapy was performed on the mediastinal tumor. On May 30, when he had a relapse, he was unsuccessfully treated with systemic chemotherapy. The leukemic cells invaded most of the organs and the patient died on July 19, 1988. It is likely that BAI of ACNU for leukemic pulmonary infiltration was effective.

Adult↗
PubMed1990

[Antibacterial activity of various antibacterial agents against methicillin-resistant Staphylococcus aureus, and difference in antibacterial activity between aminoglycosides by coagulase type. Comparison of isolates obtained in the period from 1982 to 1986 and isolates in recent 6 months].

The sensitivity of methicillin-resistant Staphylococcus aureus (MRSA) isolated in our hospital during the period from November 1988 through April 1989 to various antibacterial agents was examined. Isolates were obtained from blood (4 isolates), sputum (40), bile (1), ascites (1) and urine (4). All isolated MRSA were resistant to cefazolin, cefmetazole, cefuzonam, flomoxef, and tobramycin. More than 80% of the isolates were resistant to fosfomycin and amikacin. 60% were resistant to ofloxacin (OFLX). 46% were sensitive to minocycline. 50% or more of the isolates were sensitive to gentamicin (GM), dibekacin (DKB) and astromicin (ASTM). 88% were sensitive to netilmicin. All the isolates were sensitive to vancomycin and arbekacin. The incidence of OFLX-resistant isolates was increased compared with the results of the previous study. Most of the isolates were coagulase type II. GM, ASTM and DKB were less active against type IV isolates, but they had sufficient antibacterial activity against the type II isolates.

Aminoglycosides↗
PubMed1990

[Aplastic anemia associated with minimal serum M-protein treated successfully with repeated bolus methylprednisolone therapy].

A 61 year old woman was admitted to our hospital suffering from severe pancytopenia. Bone marrow aspiration revealed marked hypoplasia with 24.8% plasma cells. There was a small amount of IgA type M protein in serum. Multiple myeloma was ruled out on the basis that 1) the amount of serum IgA-M protein was minimal and no increase was observed, 2) no indication of monoclonality of bone marrow plasma cells was shown by immunofluorescent staining of immunoglobulins, 3) neither bone lesion nor other symptoms related to multiple myeloma were observed. Therefore, a diagnosis of aplastic anemia was made, and bolus methylprednisolone therapy (1,000 mg/day x 3 days) was performed, which brought the patient to complete remission. An oral dose of 15 mg of prednisolone is administered daily now and the remission state is being maintained. Bolus methylprednisolone therapy is performed quite often for the treatment of aplastic anemia. However, there are few reports in which remission was reached with the use of glucocorticoids alone, most having used androgens or other supportive drugs in conjunction. Here, we will discuss this case of aplastic anemia which responded to repeated bolus methylprednisolone therapy, with minimal side effects, and discuss its effectiveness. In addition, aplastic anemia associated with idiopathic monoclonal gammopathy is not reported, so this case is interesting immunologically.

Anemia, Aplastic↗
PubMed1989

Plasmin-a2-plasmin inhibitor complex in plasma of patients with thromboembolic diseases.

Plasmin generation in vivo was assessed by measuring plasma levels of plasmin-a2-plasmin inhibitor complex (PAP) with an ELISA in 42 patients with arterial or venous thromboembolic diseases. Plasma concentration of PAP was markedly elevated in patients with venous thromboembolic diseases during acute illness (3.32 +/- 3.71 ug/ml, mean +/- SD) as compared to healthy subjects (0.24 +/- 0.13 ug/ml, n = 14), while it was nearly normal (0.30 +/- 0.13 ug/ml) in patients with venous thromboembolic diseases in chronic stage. Patients with arterial thromboembolism had modestly elevated PAP; 1.05 +/- 0.77 ug/ml during acute episode, and 0.84 +/- 0.40 ug/ml in chronic stage. These results indicate that excessive activation of fibrinolytic system (plasmin generation in vivo) occurs actually in many patients with thrombotic diseases, especially in venous thromboembolic diseases during acute illness.

Acute Disease↗
PubMed1989

Sequence and expression of a frog brain complementary DNA encoding a kainate-binding protein.

Excitatory amino acids (EAAs) are important neurotransmitters in the vertebrate central nervous system. Electrophysiological and ligand-binding studies indicate that at least three different receptor subtypes for EAAs exist--N-methyl-D-aspartate, kainate and quisqualate receptor subtypes--on the basis of the preferred agonist of the receptors. We recently purified a kainate-binding protein (KBP) from frog (Rana pipiens berlandieri) brain by domoic acid (a high-affinity kainate analogue) affinity chromatography, and showed that the kainate-binding activity was associated with a protein of relative molecular mass 48,000 (Mr 48 K). The pharmacological properties and the anatomical distribution of KBP were consistent with those of a kainate receptor-ionophore complex. We have now isolated a complementary DNA encoding KBP of Mr 48 K. The deduced amino-acid sequence of the KBP has similar hydrophobic profiles to those found in other ligand-gated ion channel subunits, and shows some amino-acid sequence similarities to the corresponding regions of brain nicotinic acetylcholine receptor subunits. Localization of the KBP messenger RNAs by in situ hybridization histochemistry is compatible with the results of immunohistochemistry and receptor autoradiography studies. COS-7 cells transfected with the cDNA encoding the KBP show high-affinity kainate-binding activity with pharmacological properties similar to those of the biochemically purified KBP. These results provide the first molecular characterization of an EAA-binding site and raise the possibility that the KBP cDNA encodes a ligand-binding subunit of a kainate receptor-ionophore complex.

Amino Acid Sequence↗
PubMed1989

Characterization and N-terminal sequence of a 5 kDa polypeptide in the photosystem I core complex from spinach.

Photosystem I core complexes were isolated from spinach photosystem I particles after heat treatment in the presence of 50% (v/v) ethylene glycol (heat/EG treatment). The core complex from 58 degrees C/EG-treated particles was composed of polypeptides with apparent molecular masses of 63, 60 and 5 kDA; this complex contained the iron sulfur center Fx but lacked center FA and FB. The core complex obtained from the 70 degrees C/EG-treated preparation lacked FX and contained a lesser amount of the 5 kDa polypeptide. The N-terminal amino acid sequence of the 5 kDa polypeptide did not correspond to the sequence derived from any possible reading frame in the chloroplast DNA of liverwort or tobacco. Twelve of the first 29 N-terminal amino acids were hydrophobic, suggesting that this protein is intrinsic to the photosystem I reaction center.

Amino Acid Sequence↗
PubMed1989

Plasma von Willebrand factor proteolysis in patients with chronic myeloproliferative disorders: no possibility of ex vivo degradation by calcium-dependent proteases.

Patients with chronic myeloproliferative disorders (CMPD) frequently have abnormalities of plasma von Willebrand factor (vWf) multimers. The pathogenesis of this phenomenon is still unknown. In order to evaluate the possibility of ex vivo degradation of vWf during blood processing, we compared vWf antigen, ristocetin cofactor and the multimeric composition of vWf in plasmas obtained in the presence of trisodium citrate with or without calcium-dependent protease inhibitors (leupeptin, N-ethylmaleimide and Na2EDTA). The subjects included 20 patients with CMPD, 11 with other diseases and 8 normal subjects. In patients with CMPD and normal subjects, the values of vWf antigen, ristocetin cofactor, ristocetin cofactor/vWf antigen ratio and the relative amount of large multimers of vWf did not significantly differ from each other in plasma samples with and without protease inhibitors. In other diseases, especially in a patient with disseminated intravascular coagulation, a somewhat higher amount of large multimers were found in plasma with protease inhibitors than without inhibitors. These findings indicate that the ex vivo proteolysis during blood processing is negligible in patients with CMPD, and that the observed abnormalities in vWf is an in vivo phenomenon.

Calcium↗
PubMed1989

Activation of blood coagulation and fibrinolysis in diabetes mellitus: evaluation by plasma levels of thrombin-antithrombin III complex and plasmin-alpha 2-plasmin inhibitor complex.

Diabetes mellitus (DM) is associated with an increased incidence of vascular complications. Abnormalities in the hemostatic system contribute at least in part to the development of vascular disease or atherosclerosis. In order to assess the actual degree of activation of the coagulation and fibrinolytic systems in diabetics, plasma levels of thrombin-antithrombin III complex (TAT) and plasmin-alpha 2-plasmin inhibitor complex (PAP) were measured together with tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) in 18 patients with DM (three patients with type I DM and 15 with type II DM). Mean plasma levels of TAT (2.5 +/- SD 1.2 ng/mL) and PAP (0.9 +/- 1.2 micrograms/mL) were significantly elevated in diabetics as compared with healthy subjects (1.7 +/- 0.3 ng TAT and 0.2 +/- 0.1 micrograms PAP per mL of plasma; p = 0.009 and 0.02, respectively). Plasma antigen concentration of t-PA but not of PAI-1 was also elevated. No difference was found in the levels of these variables between type I and type II diabetics or between patients with and without retinopathy or nephropathy. These findings indicate that continuous activation of coagulation and fibrinolysis actually occurs in the majority of the patients with DM.

Adult↗
PubMed1989

Extrinsic 33-kilodalton protein of spinach oxygen-evolving complexes: kinetic studies of folding and disulfide reduction.

The 33-kDa protein is one of the three extrinsic proteins in the oxygen-evolving photosystem II complexes. The protein has one intrachain disulfide bond. On reduction of this disulfide bond, the protein was unfolded and lost its activity. On the basis of the unfolding equilibrium curve obtained by using guanidine hydrochloride, the free energy change of unfolding in the absence of guanidine hydrochloride was estimated to be 4.4 kcal/mol using the Tanford method [Tanford, C. (1970) Adv. Protein Chem. 24, 1-95] and 2.8 kcal/mol using the linear extrapolation method. The unfolding of the 33-kDa protein caused by reduction was explained in terms of the entropy change associated with reduction of the intrachain disulfide bond. The kinetics of the reduction of the disulfide bond using dithiothreitol were studied at various concentrations of guanidine hydrochloride at pH 7.5 and 25 degrees C. The disulfide bond was reduced even in the absence of guanidine hydrochloride. The unfolding and refolding kinetics of the 33-kDa protein using guanidine hydrochloride were also studied under the same conditions, and the results were compared with those for the reduction kinetics. It was shown that the reduction of the disulfide bond proceeds through a species in which the disulfide bond is exposed by local fluctuations.

Chemical Phenomena↗
PubMed1989

A single amino acid substitution in B subunit of Escherichia coli enterotoxin affects its oligomer formation.

We isolated a mutant strain of enterotoxigenic Escherichia coli by nitrosoguanidine mutagenesis, which produces an immunologically altered B subunit of heat-labile enterotoxin. This mutant B subunit was detected as a monomer on sodium dodecyl sulfate-polyacrylamide gel electrophoresis even without prior heating, suggesting a problem in oligomer formation. Furthermore, this mutant B subunit could not form holotoxin with the native A subunit, and the affinity to GM1-ganglioside receptor was 10-fold lower than that of the native B subunit. The amino acid sequence analysis of this mutant B subunit revealed only one amino acid substitution compared with the native B subunit, at the 64th position from the N terminus (valine instead of alanine). These data suggest that the alanine at position 64 from the N terminus is important for the native B subunit to form an oligomer structure and express its functions.

Alanine↗