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Biomedical subjects

K Wada

Publications and source records attributed to K Wada.

At least 649 records · Page 36Linked to original sources
PubMed1989

[Scanning electron microscopic observation on odontogenic keratocysts].

Five odontogenic keratocysts were examined by using a scanning electron microscope (SEM) on the three-dimensional ultrastructure of epithelial lining cells. The fractured surface of the specimens showed a single row of columnar or cuboidal cells perpendicular to the flat basal lamina, a four- to five-cell layer of spinous cells, and a superficial layer of flattened parakeratinized cells. At high magnification of superficial cell surface, microvillis, short discontinuous branched or anastomosing microridges were observed.

Humans↗
PubMed1989

[Dentofacial morphology of obstructive sleep apnea syndrome patients].

Sleep apnea syndrome is a condition characterized by recurrent interruption of breathing during sleep. Triad of symptoms for the disease are insomnia, daytime sleepiness and snoring. Recently, the patients complained of these symptoms have progressively increased. And so serious attention has been given to investigate the entity of this new clinical syndrome in medical and dental aspects. Three types of sleep apnea are classified; central, obstructive and mixed type. Most of patients identified this syndrome include obstructive or mixed types of sleep apnea. Obstructive sleep apnea has been presumed to have close relationships with obesity, micrognathia, retrognathia, tonsillary hypertrophy, tongue hypertrophy and so on. This study was designed to evaluate the characteristics of the dentofacial morphology in the obstructive, included mixed, sleep apnea syndrome (OSA) patients. The samples consisted of 25 adult male patients (average age of 48 years 2 months) with OSA as diagnosed by the division of respiratory disease, department of internal medicine, Kanazawa Medical University Hospital. One lateral radiographic cephalogram with the teeth in occlusion and the recording of somatic measurements, body weight and height, were obtained for each patient at visiting our orthodontic clinic. On the lateral cephalograms of whole samples, 10 angular and 6 linear measurements were carried out. Simultaneously, the body mass index (BMI) was assessed for each patient. Based on the cephalometric and somatometric measurements, the pathogenesis of obstructive sleep apnea was discussed in association with the obesity and dentofacial morphology. Results were summarized as follows: 1. The body mass index (kg/m2) ranged between 21.0 to 45.7, with a mean value of 31.0 for OSA patients. Of whom, 3 patients were mildly obese (25 or more of BMI) and 12 patients severely obese (exceeding 30 of BMI). 2. Compared with normal control samples, the means of cephalometric variables of whole samples showed the tendency of micrognathia, large gonial angle, protruded maxilla and large cranial base. 3. By principal component analysis, it was revealed that the components for the shape and position of the mandible were of more importance in OSA patients than controls. 4. Discriminatory analysis clarified significant differences in dentofacial morphology between 12 obese and 13 non-obese patients. 5. The dentofacial morphology in non-obese patients were characterized by retrognathia, micrognathia, large gonial angle and small maxilla. In accordance with previous reports, the patients with OSA were presented the tendency of obesity and micrognathia. Furthermore it was revealed that particularly in non-obese OSA patients the morphological abnormalities might be the major contributor to the pathogenesis of sleep apnea.

Adult↗
PubMed1989

Genes encoding neuronal nicotinic acetylcholine receptors.

Four genes (alpha 2, alpha 3, alpha 4, and beta 2), which encode proteins homologous to the Torpedo electric organ and vertebrate muscle nicotinic acetylcholine receptors, have been identified by cloning rat brain cDNAs. Injection of transcripts derived from these cDNAs into Xenopus laevis oocytes results in the formation of three nicotinic acetylcholine receptors. Two of these receptors, alpha 3/beta 2 and alpha 4/beta 2, have the characteristics of ganglionic nicotinic receptors. The third (alpha 2/beta 2) exhibits a previously undescribed pharmacology and thus represents a novel subtype that may be expressed in the brain. The wide distribution of alpha 2, alpha 3, alpha 4, and beta 2 transcripts in the brain indicates that neuronal nicotinic acetylcholine receptors are a major neurotransmitter receptor system.

Animals↗
PubMed1989

[A case of coexistent adenocarcinoma and primary malignant lymphoma of the stomach].

A case of a simultaneous adenocarcinoma and a primary malignant lymphoma of the stomach is presented. A sixty-one-year-old male was referred to us with epigastralgia. Gastroscopy and a biopsy revealed a *** c-like lesion in the stomach and, on histological examination, was determined as being an adenocarcinoma. A proximal gastrectomy and an R2-resection of lymph nodes then was performed. A pathological examination of the resected stomach disclosed a malignant lymphoma neighboring the adenocarcinoma. The presence of a simultaneous carcinoma and a malignant lymphoma of the stomach is quite rare, with only twenty-eight documented patients reported in the Japanese literature. This entity is discussed.

Adenocarcinoma↗
PubMed1988

Phospholipase A2 from human synovial fluid: purification and structural homology to the placental enzyme.

Phospholipase A2 (PLA2) has been purified to homogeneity from synovial fluid of arthritis patients. The 3-step purification procedure included: a) dialysis against 5mM NH4-acetate, pH 5.5, in which PLA2 precipitated with euglobulins, followed by extraction with 0.4 M NaCl/0.05 M NH4-acetate, pH 5, b) chromatography on CM-cellulose, c) preparative gel electrophoresis in the presence of 0.1% Na-dodecyl sulfate and electroelution of the band containing the enzyme. Automated sequence analysis has indicated that the protein is pure, with the following NH2-terminal sequence: Asn-Leu-Val-Asn-Phe-His-Arg-Met-Ile-Lys-Leu-Thr-Thr-. A computer search revealed that all proteins with greater than 75% analogies in NH2-terminal sequences were PLA2's from various snake venoms. When PLA2 was purified from human placental membranes and analyzed, it was found to contain an identical sequence of 13 residues from the NH2-terminus. This and other characteristics suggest that the two human enzymes are closely related, if not identical.

Amino Acid Sequence↗
PubMed1988

Behavior of protein S during long-term oral anticoagulant therapy.

It has recently been reported that a natural anticoagulant, protein S (PS), is depressed during oral anticoagulation. Since more detailed information is required from the clinical standpoint, we measured plasma levels of PS [both total and free (not complexed) PS antigen], C4b-binding protein (C4bp) and other vitamin K-dependent proteins (factors II, VII, IX, X and protein C) in 60 plasma samples from patients on long-term oral anticoagulant therapy with warfarin. Together with the reduction of other vitamin K-dependent plasma proteins, PS decreased during warfarin treatment, being dependent on the intensity of the therapy. A considerable variation in plasma PS levels was also observed among individuals with a similar intensity of anticoagulation. Plasma concentration of C4bp was closely correlated with total PS level, and free PS/total PS ratio was independent of thrombotest values. These findings indicate that long-term oral anticoagulant therapy results in the suppression of the synthesis of PS, and that its reduction is on the whole balanced with C4bp and vitamin K-dependent coagulation factors. It was suggested that the metabolism of C4bp might be regulated by the plasma PS level, although this hypothesis needs further exploration.

Administration, Oral↗
PubMed1988

Properties and structure of the soluble ferredoxin from Synechococcus 6301 (Anacystis nidulans). Relationship to gene sequences.

Photoautotrophic cultures of the unicellular cyanobacterium Synechococcus 6301 (Anacystis nidulans) possessed a single [2Fe-2S] ferredoxin with a midpoint redox potential of -385 mV. Determination of the amino acid sequence of the ferredoxin showed that it consisted of 98 residues, with methionine and tryptophan both absent, and with only the four cysteine residues that are required to co-ordinate the iron-sulphur cluster. Comparisons with other ferredoxin sequences showed that most resemblance was to those from filamentous cyanobacteria, with up to 87% homology. There was less resemblance to the ferredoxins of unicellular cyanobacteria, with 25 differences when compared with that from another Synechococcus sp. However, the sequence of Synechococcus 6301 ferredoxin was identical with that derived for a gene sequence for a putative ferredoxin from the genotypically closely related Synechococcus 7942 (Anacystis nidulans R2). In contrast, the sequence showed substantial differences from that corresponding to a putative ferredoxin gene from Synechococcus 6301 reported by Cozens & Walker [(1988) Biochem. J. 252, 563-569].

Amino Acid Sequence↗
PubMed1988

Functional expression of a new pharmacological subtype of brain nicotinic acetylcholine receptor.

A new type of agonist-binding subunit of rat neuronal nicotinic acetylcholine receptors (nAChRs) was identified. Rat genomic DNA and complementary DNA encoding this subunit (alpha 2) were cloned and analyzed. Complementary DNA expression studies in Xenopus oocytes revealed that the injection of messenger RNAs (mRNAs) for alpha 2 and beta 2 (a neuronal nAChR subunit) led to the generation of a functional nAChR. In contrast to the other known neuronal nAChRs, the receptor produced by the injection of alpha 2 and beta 2 mRNAs was resistant to the alpha-neurotoxin Bgt3.1. In situ hybridization histochemistry showed that alpha 2 mRNA was expressed in a small number of regions, in contrast to the wide distribution of the other known agonist-binding subunits (alpha 3 and alpha 4) mRNAs. These results demonstrate that the alpha 2 subunit differs from other known agonist-binding alpha-subunits of nAChRs in its distribution in the brain and in its pharmacology.

Amino Acid Sequence↗
PubMed1988

Primary structure of chicken liver acetyl-CoA carboxylase deduced from cDNA sequence.

The complete amino acid sequence of acetyl-CoA carboxylase from chicken liver has been deduced by cloning and sequence analysis of DNA complementary to its messenger RNA. The results were confirmed by Edman degradation of peptide fragments obtained by digestion of the enzyme polypeptide with Achromobacter proteinase I or staphylococcal serine proteinase. Chicken liver acetyl-CoA carboxylase is predicted to be composed of 2,324 amino acid residues, having a calculated molecular weight of 262,706. The biotin carboxyl carrier protein domain is located in the middle region of the enzyme polypeptide. The amino-terminal portion of the acetyl-CoA carboxylase has been found to exhibit a homologous primary structure to that of carbamyl phosphate synthetase. Localization of possible functional domains including biotin carboxylase subsite in the acetyl-CoA carboxylase polypeptide is discussed.

Acetyl-CoA Carboxylase↗
PubMed1988

Morphometric analysis of hepatocellular carcinoma.

In order to characterize the cytological features of highly differentiated hepatocellular carcinoma (HCC), a comparative morphometric study was made by observing 30 cases of HCCs and controls (normal, cirrhotic, and atrophic livers). Among trabecular HCCs, normotrabecular subtype (1-2 cell thick cell plate) usually showed minimal cytological atypism and was categorized as well or highly differentiated HCC. Using an image analyzer, the following 4 parameters were applied to quantitate the hepatocyte changes: mean cell size (C), mean nuclear size (N), nucleocytoplasmic (N/C) ratio and a coefficient of variance (CV = index of anisokaryosis). In normotrabecular HCCs, C was slightly but significantly reduced when compared with normal and cirrhotic livers (t-test: p less than 0.005). The value was further reduced in mid- and macrotrabecular HCCs. Normotrabecular HCCs showed almost the same N value as normal and cirrhotic livers but displayed significantly a higher N/C value than those of controls (t-test: p less than 0.001). The N/C ratio became even greater in other types of HCCs. While CV was relatively constant in other HCC groups and controls, it was extremely high in the pleomorphic type of HCC and liver cell dysplasia. The results indicated that a reduction in C and increase in N/C ratio, which appear as "nuclear crowding" in histological specimens, actually occurs in well differentiated HCC. For the histologic diagnosis of well differentiated HCC, it would be very important to examine liver specimens with these observations in mind.

Atrophy↗
PubMed1988

Primary structure and expression of beta 2: a novel subunit of neuronal nicotinic acetylcholine receptors.

A new subunit, beta 2, of the neuronal nicotinic receptor family has been identified. This subunit has the structural features of a non-agonist-binding subunit. We provide evidence that beta 2 can substitute for the muscle beta 1 subunit to form a functional nicotinic receptor in Xenopus oocytes. Expression studies performed in oocytes have demonstrated that three different neuronal nicotinic acetylcholine receptors can be formed by the pairwise injection of beta 2 mRNA and each of the neuronal alpha subunit mRNAs. The beta 2 gene is expressed in PC12 cells and in areas of the central nervous system where the alpha 2, alpha 3, and alpha 4 genes are expressed. These results lead us to propose that the nervous system expresses diverse forms of neuronal nicotinic acetylcholine receptors by combining beta 2 subunits with different agonist-binding alpha subunits.

Acetylcholine↗
PubMed1988

Purification and characterization of chicken liver cathepsin B.

Cathepsin B was purified, 400-fold, to homogeneity from chicken liver. The enzyme comprised a mixture of two kinetically indistinguishable forms (approximately 1:1), which were separated on concanavalin A (Con A)-Sepharose; one consisting of Mr 25,500 and 5,000 polypeptide chains bound to Con A-Sepharose but the other, composed of Mr 24,500 and 5,000 polypeptide chains, did not. N-terminal amino acid sequence analyses of a mixture of the Mr 25,500 and 24,500 polypeptide chains, and of the Mr 5,000 polypeptide chain revealed single amino acid sequences, respectively. These amino acid sequences were homologous to those of the heavy and light chains of mammalian enzymes, respectively. The chicken liver and mammalian cathepsin B were similar in structure and properties.

Acetyl-CoA Carboxylase↗
PubMed1988

Complete amino acid sequence of ferredoxin from Peridinium bipes (Dinophyceae).

The amino acid sequence of the major ferredoxin component isolated from a dinoflagellate, Peridinium bipes, was completely determined. Staphylococcus aureus V8 proteolytic, tryptic and chymotryptic peptides of Cm-ferredoxin were prepared and sequenced. The sequence was Phe-Lys-Val-Thr-Leu-Asp-Thr-Pro-Asp-Gly-Lys-Lys-Ser-Phe-Glu-Cys- Pro-Gly-Asp-Ser-Tyr-Ile-Leu-Asp-Lys-Ala-Glu-Glu-Glu-Gly-Leu-Glu-Leu-Pro- Tyr-Ser - Cys-Arg-Ala-Gly-Ser-Cys-Ser-Ser-Cys-Ala-Gly-Lys-Val-Leu-Thr-Gly-Ser-Ile- Asp-Gln - Ser-Asp-Gln-Ala-Phe-Leu-Asp-Asp-Asp-Gln-Gly-Gly-Asp-Gly-Tyr-Cys-Leu-Thr- Cys-Val - Thr-Tyr-Pro-Thr-Ser-Asp-Val-Thr-Ile-Lys-Thr-His-Cys-Glu-Ser-Glu-Leu. It was composed of 93 amino acid residues with 7 cysteine residues, the highest number found among the chloroplast-type ferredoxins so far sequenced. A cysteine residue was found for the first time at the 89th position in a chloroplast-type ferredoxin. Calculation of the numbers of amino acid differences among chloroplast-type ferredoxins indicates that the Peridinium ferredoxin is far divergent not only from higher plant ferredoxins but also from blue-green algal ferredoxins.

Amino Acid Sequence↗
PubMed1988

Tolerance induction of alloreactivity by portal venous inoculation with allogeneic cells followed by the injection of cyclophosphamide. II. Cellular and molecular mechanisms underlying tolerance.

BALB/c mice receiving allogeneic C3H/He or C57BL/6 spleen cells via portal venous (p.v.) route or a single administration of cyclophosphamide (Cy) were capable of rejecting the respective allogeneic C3H/He- or C57BL/6-derived tumor cells. In contrast, the combined treatment of p.v. inoculation with allogeneic lymphocytes and Cy administration abrogated the capability of rejecting allogeneic tumor cells. Such abrogation of alloreactivity was alloantigen-specific and associated with the suppression of potentials to generate delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte (CTL) responses to alloantigens. This was further substantiated by the inhibition of molecular mechanisms underlying anti-allo-DTH and -CTL responses. Thus, the above combined treatment led to the decreased production of lymphokines such as macrophage-activating factor (MAF) and interleukin 2 (IL2) following the stimulation with the relevant alloantigens. These results demonstrate that p.v. inoculation of allogeneic cells followed by a single administration of Cy results in the effective elimination of alloreactivity as verified by the suppression of cellular and molecular mechanisms of alloreactive responses.

Animals↗
PubMed1988

Effect of tiopronin on prostaglandin synthesis in rabbit kidney medulla slices.

The effect of 2-mercaptopropionylglycine (tiopronin), which is widely used for the treatment of various hepatic disorders, on the generation of medullary prostaglandins (PG) E2 and F2 alpha has been examined. Tiopronin had a potent inhibitory effect on PG E2 formation. Simultaneously, PG F2 alpha production was increased. In the presence of tiopronin the net increased amount of PG F2 alpha was much smaller than the net decreased amount of PG E2 (6-20%). These results suggest that tiopronin has the potential to modulate PG E2 and F2 alpha synthesis by affecting endoperoxide E2 isomerase or endoperoxide reductase and that this effect may represent some pharmacological action of the drug.

Animals↗