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Biomedical subjects

H Sugiura

Publications and source records attributed to H Sugiura.

At least 19 recordsLinked to original sources
PubMed1992

Developmental changes in the levels of Ca2+/calmodulin-dependent protein kinase II alpha and beta proteins in soluble and particulate fractions of the rat brain.

Developmental changes in Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) have been immunochemically examined in the forebrain, cerebellum and brainstem of the rat using antibodies against its alpha or beta protein. The concentration of alpha and beta proteins varied markedly in different brain regions at increasing postnatal ages. In early postnatal brain, the concentration of the alpha and beta proteins was low, and a large increase was observed between postnatal days 10 and 30. The maximum expression of the alpha protein was in the order of 6.01, 2.33 and 0.168 micrograms/mg of forebrain, brainstem and cerebellum proteins respectively, in the soluble or particulate fraction. On the other hand, that of the beta protein was in the order of 1.81, 0.495 and 0.291 micrograms/mg of forebrain, cerebellum or brainstem protein. The ratio of alpha and beta proteins also differed in the soluble and particulate fractions. The maximum expression of the alpha protein was observed at day 30 in soluble and particulate fractions of forebrain, and at day 20 in those of the brainstem. The major alpha protein peak was observed on or after day 30 in particulate and soluble fractions from cerebellum, respectively. The maximum expression of the beta protein was observed at day 20 in soluble and particulate fractions of the forebrain as well as in soluble fraction of the cerebellum, and was observed at day 30 in the particulate fraction of cerebellum. The expression of the alpha and beta proteins roughly correlated with the CaM kinase II activity from forebrain and brainstem.

Aging↗
PubMed1992

Cloning and disruption of the cefG gene encoding acetyl coenzyme A: deacetylcephalosporin C o-acetyltransferase from Acremonium chrysogenum.

Acetyl CoA: deacetylcephalosporin C o-acetyltransferase(DCPC-ATF) catalyses the final step in the biosynthesis of cephalosporin C (CPC) in Acremonium chrysogenum. The gene encoding DCPC-ATF, cefG, has been isolated from an A. chrysogenum genomic library using a DCPC-ATF cDNA probe. Nucleotide sequence analysis revealed that cefG contains two short introns of 79bp and 65bp. The gene was found to be closely linked to the cefEF gene encoding deacetoxycephalosporin C synthetase/deacetylcephalosporin C synthetase, which catalyses the preceding two steps in the pathway. The two genes are separated by a 1114 bp segment from which they are divergently transcribed. Introduction of the cloned cefG gene to A.chrysogenum resulted in an increased level of DCPC-ATF activity. A plasmid carrying a cefG gene interrupted in the coding region by a selectable marker for resistance to hygromycin B was constructed and used to disrupt the cefG locus in A.chrysogenum. The cefG-disrupted strains were found to lack the ability to produce CPC, and accumulated its precursor, deacetylcephalosporin C in the culture broth. Southern hybridization analysis confirmed that the disruption resulted from a gene replacement event at the cefG locus.

Acetyltransferases↗
PubMed1992

Molecular cloning of acetyl coenzyme A: deacetylcephalosporin C o-acetyltransferase cDNA from Acremonium chrysogenum: sequence and expression of catalytic activity in yeast.

Acetyl CoA: deacetylcephalosporin C o-acetyltransferase(DCPC-ATF) catalyses the final step in the biosynthesis of cephalosporin C, the conversion of deacetylcephalosporin C to cephalosporin C. A cDNA encoding DCPC-ATF has been isolated from a cDNA library of a cephalosporin C producing fungus Acremonium chrysogenum using oligonucleotide probes based on N-terminal amino acid sequences of the enzyme. The cDNA contains a single large open reading frame for a putative precursor consisting of 12 amino acid(AA) leader peptide of unknown function, 274 AA large subunit and 126 AA small subunit at the carboxyl end. The cDNA was expressed in yeast exhibiting a functional DCPC-ATF activity. It was also indicated that the leader peptide was not essential for expression of the enzyme activity. The primary structure of DCPC-ATF shows significant homology with those of acetyl CoA: homoserine o-acetyltransferase in Saccharomyces cerevisiae and Ascobolas immersus.

Acetyltransferases↗
PubMed1992

Action potential conduction between guinea pig ventricular cells can be modulated by calcium current.

We used cell pairs electrically coupled with relatively high intercellular resistance to investigate the involvement of calcium current in the origin of the source current during the conduction process of the action potential (AP). Three interventions were used to reduce the calcium current: a specific calcium channel blocker [nifedipine (NIF)], premature stimulation, and increments in the frequency of stimulation of the cell. The ionic membrane current (Iion) after the peak of the AP of the stimulated cell was positive and small when the cell was uncoupled. However, when the stimulated cell was coupled to a cell model or to another cell, Iion during this period became negative and large to supply the coupling current. A rapid early repolarization of the AP occurred in the stimulated cell because of the removal of charge from the stimulated cell. NIF decreased the magnitude of the net negative Iion during this period and caused a more rapid early repolarization in the stimulated cell. NIF increased the delay between the activations of two coupled cells at a given coupling resistance (Rc) but decreased the longest delay that could be produced without conduction failure for a given cell pair. The highest Rc below which conduction of AP occurred was also decreased by NIF. Premature stimulation and an increase of the stimulation frequency also caused an increase in the extent of the early repolarization and increased the delay between two cell activations at a given Rc. Conduction block occurred with sufficient prematurity or at a sufficiently high frequency of stimulation even though activation of the stimulated cell occurred for each stimulus. The Iion that flows during the early plateau phase of the AP in the stimulated cell became negative and significantly large by coupling two cardiac cells together. This current flow is a major component needed to supply the coupling current through the intercellular resistance. The decrease of calcium current caused a decrease in the magnitude of this net inward ionic current, resulting in an increase of the rate of early repolarization and an increase in the conduction delay between two cells at a given Rc. These results suggest the involvement of calcium current in the conduction process when cells are coupled at relatively high Rc.

Action Potentials↗
PubMed1992

Purification of acetyl coenzyme A: deacetylacephalosporin C O-acetyltransferase from Acremonium chrysogenum.

Acetyl CoA: deacetylcephalosporin C O-acetyltransferase, which catalyzes the final step of the biosynthetic pathway to cephalosporin C, was stabilized by a buffer solution containing 7-aminocephalosporanic acid and purified over 1300-fold from Acremonium chrysogenum. The purified enzyme has a molecular weight of 55,000 as measured by gel filtration. SDS-polyacrylamide gel electrophoresis showed two subunit bands corresponding to molecular weights of 27,000 and 14,000. The enzyme has an isoelectoric point at pH 4.0 and optimum activity at pH 7.5.

Acetyltransferases↗
PubMed1992

Giant hypertrophic gastritis and acute hepatitis associated with cytomegalovirus infection.

A 38-year-old man developed prominent hypoproteinemia after acute elevation of serum transaminase levels. Giant hypertrophy of the gastric mucosa, a short serum albumin half-life, and the absence of massive hepatocyte necrosis established the diagnosis of protein-losing gastropathy. The hypoproteinemia, gastric fold hypertrophy and hepatitis remitted spontaneously within 4 months. A high antibody titer against cytomegalovirus suggested an association between the viral infection and the patient's disease.

Acute Disease↗
PubMed1992

Lymphocyte transformation test for house dust mite in atopic dermatitis: relationship between mite antigens for type I and type IV allergy.

Using a crude extract obtained from Dermatophagoides farinae, and its four fractions (I, II, III and IV) partially purified by high-speed gel filtration chromatography, scratch tests and lymphocyte transformation tests (LTTs) were performed on 37 patients with atopic dermatitis. Crude mite antigen provoked positive scratch test reactions in 25 (68%), and positive LTT reactions in 19 (51%) of the 37 patients examined. Mite antigen fractions I, II, III and IV induced a positive LTT reaction in 19, 22, 17 and 7 patients, respectively. Of the 65 positive LTT reactions, 25 accompanied a positive scratch test to the antigen fraction which provoked the positive LTT reaction, but 40 accompanied a negative scratch test. These findings suggest that house dust mite antigen fractions for type IV allergy are different from those for type I allergy in a considerable proportion of patients with atopic dermatitis.

Adolescent↗
PubMed1992

Mast cell invasion of peripheral nerve in skin lesions of atopic dermatitis.

To ascertain whether or not a spatial relationship between mast cells and peripheral nerves is present in skin lesions of atopic dermatitis, 10 biopsy specimens of the skin lesions were examined with both semi-thin and ultrathin serial sections. Mast cell invasion of peripheral nerves was observed in 9 out of the 10 biopsy specimens (4 subacute lesions, 3 lichenified lesions, and 3 prurigo lesions). The mast cells within peripheral nerves often showed degranulation, and the nerve fiber bundle showed conspicuous edema. The degranulation of mast cells within peripheral nerve bundles and edema of the nerve bundle may pay a role in provoking or aggravating itchiness of atopic dermatitis.

Adolescent↗
PubMed1992

Stimulation of corticosterone secretion by dietary histidine in rats.

1. Liver glycogen accumulated within 3 days after the initiation of a histidine-excess diet. Serum corticosterone increased and serum insulin decreased, but plasma glucagon remained unchanged. 2. When 2 mmol (310 mg) of histidine was administered to fasted rats, serum corticosterone increased after 5 hr and tended to be higher 9 hr after administration. 3. Liver glycogen tended to accumulate after 5 hr and had accumulated significantly after 9 hr.

Adrenal Glands↗
PubMed1992

Crystalloids in angiomyolipoma. 1. A previously unnoticed phenomenon of renal angiomyolipoma occurring at a high frequency.

We present a description of unique crystalloids in renal angiomyolipoma that have not previously been reported. The crystalloids cannot be identified by hematoxylin-and-eosin staining. Detailed observation after diastase treatment followed by PAS staining revealed needle- and rod-like crystalloids, which were clearly seen even by light microscopy, in 11 of 17 patients. Their appearance was characterized by the following phenomena: (a) They appeared mainly in large epithelioid smooth-muscle cells; (b) they appeared at a relatively high frequency at sites where smooth-muscle cells showed diffuse proliferation and where a hemangiopericytic pattern was observed; (c) they were often detected easily even at a site with a sarcomatous appearance; and (d) PAS-positive, diastase-resistant granules were often observed by light microscopy in the vicinity of crystalloids in all 17 patients. Electron-microscopic observation of one patient also revealed characteristic crystalloids. Prior to our study, only one patient had been reported to show crystalloids by electron microscopy, and the crystalloids were interpreted as renin. However, our study used Bowie's staining and immunohistochemistry to prove they were not renin. The nature of the crystalloids still needs to be elucidated. The fact that they closely resemble structures seen in alveolar soft part sarcoma provides one clue to their identification.

Adult↗
PubMed1992

[A study of risk factor in osteoporosis, femoral neck fracture and colles' fracture].

This work studied risk factors of osteoporosis, femoral neck fracture and Colles' fracture. The results were compared with those of a healthy group. Milk intake was frequent in the healthy group, but rare in the femoral neck fracture or Colles' fracture group. Most of osteoporosis and femoral neck fracture group were bed ridden, or stayed indoors for a long time before injury. They weighed less and were thin as compared to the healthy group. Decrease of activities of daily living and less body weight were risk factors of osteoporosis and femoral neck fracture, but these risk factors were more predominant in the femoral neck fracture than osteoporosis group. In this study, 74.4% of the patients with femoral neck fracture also had osteoporosis and 33.3% with Colles' fracture had osteoporosis. Colles' fracture was related to injury force and femoral neck fracture was found to be closely related to osteoporosis.

Activities of Daily Living↗
PubMed1992

[Effects of exercise and calcium-intake on bone hardness and bone constituents in aged mice].

Effects of exercise and differing calcium intakes on bone hardness and bone constituents were examined using mice (40 weeks old) in successive stages of senescence to contribute to our understanding of preventive measures against osteoporosis. In the present study, the mice were divided into four groups, combinations of stock diet (Ca: 1.25 g/100 g) or low Ca diet (Ca: 0.15 g/100 g), with or without physical exercise (forced exercise, 40 min/day at a velocity of 12 m/min) and maintained in their respective conditions for 16 weeks. Autopsies were performed or representative mice every four weeks (44, 48, 52, 56 weeks old). The obtained results are summarized as follows: 1) In female mice highest values for femoral bone weight were observed after 48 weeks in the mice exposed to forced exercise and on a stock diet and had a significant difference from the other groups. No difference was observed in male mice. 2) Bone hardness had a tendency to be reduced with age in all groups. The velocity of diminution was small in the mice kept on stock diet as compared to those on a low Ca diet. The highest bone hardness was observed in the mice kept in forced exercise and stock diet group at every stage. 3) Bone constituents, Ca, P and hydroxyproline, showed no differences in concentration per weight of bone. But higher total content in the femur was obtained in the mice kept on a stock diet. 4) No differences in concentration of serum calcitonin and parathormone were seen in every group of male mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1991

Evidence that Ser-82 is a unique phosphorylation site on vimentin for Ca2(+)-calmodulin-dependent protein kinase II.

We identified the sites on vimentin that are phosphorylated by Ca2(+)-calmodulin-dependent protein kinase II (CaM-kinase II). Sequential analysis of the purified phosphopeptides demonstrated that the sites are -Thr-Arg-Thr-Tyr-Ser(PO4)38-Leu-Gly-Ser-Ala- and -Val-Arg-Leu-Leu-Gln-Asp-Ser(PO4)82-Val-Asp-, which are located within the amino-terminal head domain of vimentin. For Ser-82 but not Ser-38, the proposed CaM-kinase II recognition amino acid sequence (Arg-X-X-Ser/Thr) was not found. Studies with a series of synthetic peptide analogs corresponding to Ser-82 and its surrounding amino acid sequence indicate that Asp-84 acts as an essential substrate specificity determinant for the Ser-82 phosphorylation by CaM-kinase II. The CaM-kinase II recognition site may be more extensive than heretofore determined.

Amino Acid Sequence↗
PubMed1991

Successful treatment of disseminated cutaneous cytomegalic inclusion disease associated with Hodgkin's disease.

A case of disseminated cutaneous cytomegalic inclusion disease associated with Hodgkin's disease is described. The patient had a diffuse eruption of pruritic, erosive erythematous nodules. Histologically, many inclusion bodies were observed in perivascular areas of the skin lesions. Immunohistologically, the inclusion bodies positively stained with both anticytomegalovirus antibody and anti-factor VIII-related antibody. On electron microscopy many virus particles and dense bodies were found in the area where inclusion bodies were observed. Treatment with high-dose intravenous acyclovir and a large amount of immunoglobulin resulted in prompt healing of the skin lesions. Subsequently, the patient's Hodgkin's disease was well controlled on chemotherapy. The patient steadily improved without relapse of skin lesions 1 year after antiviral therapy was administered.

Aged↗
PubMed1991

Unidirectional block between isolated rabbit ventricular cells coupled by a variable resistance.

We have used pairs of electrically coupled cardiac cells to investigate the dependence of successful conduction of an action potential on three components of the conduction process: (a) the amount of depolarization required to be produced in the nonstimulated cell (the "sink" for current flow) to initiate an action potential in the nonstimulated cell, (b) the intercellular resistance as the path for intercellular current flow, and (c) the ability of the stimulated cell to maintain a high membrane potential to serve as the "source" of current during the conduction process. We present data from eight pairs of simultaneously recorded rabbit ventricular cells, with the two cells of each pair physically separated from each other. We used an electronic circuit to pass currents into and out of each cell such that these currents produced the effects of any desired level of intercellular resistance. The cells of equal size (as assessed by their current threshold and their input resistance for small depolarizations) show bidirectional failure of conduction at very high values of intercellular resistance which then converts to successful bidirectional conduction at lower values of intercellular resistance. For cell pairs with asymmetrical cell sizes, there is a large range of values of intercellular resistance over which unidirectional block occurs with conduction successful from the larger cell to the smaller cell but with conduction block from the smaller cell to the larger cell. We then further show that one important component which limits the conduction process is the large early repolarization which occurs in the stimulated cell during the process of conduction, a process that we term "source loading."

Action Potentials↗
PubMed1991

Structural features of Ca2+/calmodulin-dependent protein kinase II revealed by electron microscopy.

The molecular conformation of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) from the rat forebrain and cerebellum was studied by means of EM using a quick-freezing technique. Each molecule appeared to be composed of two kinds of particles, with one larger central particle and smaller peripheral particles and had shapes resembling that of a flower with 8 or 10 "petals". A favorable shadowing revealed that each peripheral particle had a thin link to the central particle. We predicted that the 8-petal molecules and 10-petal molecules were octamers and decamers of CaM kinase II subunits, respectively, each assembled with the association domains of subunits gathered in the center, and the catalytic domains in the peripheral particles. Binding of antibodies to the enzyme molecules suggested that molecules with 8 and 10 peripheral particles were homopolymers composed only of beta subunit and of alpha subunit, respectively, specifying that CaM kinase II consists of homopolymer of either alpha or beta subunits.

Animals↗
PubMed1991

Giant cell fibroblastoma. A case report and immunohistochemical comparison with ten cases of dermatofibrosarcoma protuberans.

A 7-year-old boy with giant cell fibroblastoma (GCF) of the skin and subcutaneous tissue of the right chest wall is described. To date, the histogenesis of GCF has not been clarified. The reason for the diversity of immunohistochemical data among various authors may be because the specimens studied were from only part of the lesion, or reduction of antigenicity through the preparation process. However, our findings based on studies of many specimens from various parts of the tumor for accurate immunohistochemical evaluation suggest that GCF may be a myofibrohistiocytic tumor. Recently, the suggestion that GCF is a juvenile form of dermatofibrosarcoma protuberans (DFSP) has been reported. In addition to the present case, we performed immunohistochemical examination of 10 cases of definitely diagnosed DFSP for comparison. The immunohistochemical characteristics of these two neoplasms were concordant. However, from clinical and morphological viewpoints, it seems premature to recognize GCF as a juvenile form of DFSP.

Child↗