Search PubMed⌕ Search

Biomedical subjects

K Waki

Publications and source records attributed to K Waki.

At least 19 recordsLinked to original sources
PubMed2001

Cloning of a cDNA encoding EIN3-like protein (DC-EIL1) and decrease in its mRNA level during senescence in carnation flower tissues.

A cDNA clone encoding a putative EIN3-like protein (DC-EIL1) was obtained from total RNA isolated from senescing carnation (Dianthus caryophyllus L.) petals using RT-PCR and RACE techniques. The cDNA (2382 bp) contained an open reading frame of 1986 bp corresponding to 662 amino acids. The amino acid sequence of the N-terminal half of the protein, ranging from 80-300 amino acid residues, had 84% identity with that of the corresponding regions of Arabidopsis EIN3 and tobacco TEIL, although the overall identity was 49% and 52%, respectively. Northern blot analysis revealed that the amount of mRNA corresponding to DC-EIL1 decreased in flower tissues, especially in petals, during natural senescence and senescence induced by exogenously applied ethylene or ABA.

Amino Acid Sequence↗
PubMed2000

Photooxidation mechanism of nitrogen-containing compounds at TiO2/H2O interfaces: an experimental and theoretical examination of hydrazine derivatives.

The photocatalytic oxidation of oxalyldihydrazide, N,N'-bis(hydrazocarbonyl)hydrazide, N,N'-bis(ethoxycarbonyl)hydrazide, malonyldihydrazide, N-malonyl-bis[(N'-ethoxycarbonyl)hydrazide] was examined in aqueous TiO2 dispersions under UV illumination. The photomineralization of nitrogen and carbon atoms in the substrates into N2 gas, NH4+ (and/or NO3-) ions, and CO2 gas was determined by HPLC and GC analysis. The formation of carboxylic acid intermediates also occurred in the photooxidation process. The photocatalytic mechanism is discussed on the basis of the experimental results, and with molecular orbital (MO) simulation of frontier electron density and point charge. Substrate carbonyl groups readily adsorb on the TiO2 surface, and the bonds between carbonyl group carbon atoms and adjacent hydrazo group nitrogen atoms are cleaved predominantly in the initial photooxidation process. The hydrazo groups were photoconverted mainly into N2 gas (in mineralization yields above 70%) and partially to NH4 ions (below 10%). The formation of NO3- ions was scarcely recognized.

Catalysis↗
PubMed2000

Left atrial myocardial extension onto pulmonary veins in humans: anatomic observations relevant for atrial arrhythmias.

INTRODUCTION: Electrophysiologic studies have shown that spontaneous initiation of atrial fibrillation (AF) by ectopic beats may originate from within pulmonary veins. The extensions of left atrial myocardium are considered to play a role, but there is little detailed anatomic information available, particularly in humans. METHODS AND RESULTS: Thirty-nine human autopsy hearts were studied; 22 with AF and 17 without atrial arrhythmias. The muscle fiber arrangement of the left atrial wall and pulmonary veins was dissected. In 18 hearts, myocardial sleeves were studied microscopically; in five hearts, three-dimensional reconstruction of the fiber arrangement in the myocardial sleeves was performed. Of 99 pulmonary veins examined, 96 contained a myocardial sleeve. The length of the sleeves was largest in the superior pulmonary veins (P < 0.01). There were no statistically significant differences between uniform and nonuniform muscle fiber arrangements. Microscopic evaluation revealed myocardial sleeves positioned on the adventitial side of the pulmonary vein, separated from the muscular media by a fibrofatty tissue plane. The most distal zone of the myocardial sleeves showed increasing fibrosis with encapsulation of small groups of myocardial cells and eventually with total disappearance of atrophic cells within fibrous tissue. Node-like structures were not encountered. There was no relationship with presence or absence of AF. CONCLUSION: The observation that the peripheral zones of myocardial sleeves are associated with increasing connective tissue deposition between myocardial muscle groups suggests a degenerative change that, from the histologic viewpoint, fits with progressive ischemia. These changes could provide a basis for microreentry and, hence, for atrial arrhythmias.

Adult↗
PubMed2000

Right atrial flutter isthmus revisited: normal anatomy favors nonuniform anisotropic conduction.

INTRODUCTION: The "flutter isthmus," the part of the lower right atrium between the eustachian valve and the tricuspid annulus inferior to the coronary sinus os, is considered the crucial zone for conduction delay necessary for the genesis of atrial flutter. However, the underlying mechanism remains unclear. METHODS AND RESULTS: We studied the "flutter isthmus" in 50 hearts obtained at autopsy from patients without atrial tachyarrhythmias. The muscular trabecular arrangement was dissected carefully by peeling off the endocardium. Documentation of the trabecular arrangement focused, in particular, on the question of whether there was a uniform pattern of well-aligned muscle trabeculae or a nonuniform architecture. It appeared that a nonuniform trabecular pattern prevailed (37/50 [74%]). In these hearts, the muscular arrangement showed abundant cross-overs and interlacing trabeculae, particularly in the zone immediately inferior to the coronary sinus os. Connections also occurred along the inferior rim of the os. CONCLUSION: The normal anatomy of the lower right atrium favors nonuniform muscular trabeculation, with interlacing bundles and a multitude of cross-overs. The potential for conduction delay is present in the vast majority of normal hearts. This raises the question as to what has changed in the hearts of patients with atrial flutter such that the potential for conduction delay and reentry has become effective.

Adolescent↗
PubMed2000

Morphology of the human atrioventricular node is age dependent: a feature of potential clinical significance.

INTRODUCTION: Advances in catheter ablation procedures have created the need to understand better the morphology of the AV node (AVN), particularly as it relates to age. METHODS AND RESULTS: This study was based on 40 normally structured hearts obtained at autopsy from patients without a history of tachyarrhythmia in the following age ranges: < 1 year (n = 19); 1-12 years (n = 11); and 12-20 years (n = 10). In 38 hearts, the AV septal junctional area was removed en bloc and serially sectioned at 10-microm thickness at right angles to the AV annulus. The length of the compact node and the rightward and leftward inferior extensions were calculated. Computer-assisted three-dimensional reconstructions were made of six hearts. The ratio of right extension to compact AVN showed a statistically significant increase with age; the increase in ratio of left extension to compact AVN was not statistically significant. In addition, with increasing age the geometry of the AVN changed from a half-oval to a spindle shape, concomitant with development of a distinct so-called muscular AV septum. The three-dimensional reconstructions showed widening of the transitional cell zone with an increase in fibrofatty tissue related to age. CONCLUSION: The AVN, inferior extensions, and transitional cell zone show distinct age-related changes that may be clinically relevant. The increase in length of the inferior extensions may set the scene for AVN reentry and could explain why this condition is more frequent in young adults than in infants.

Adolescent↗
PubMed1999

A case of lymphocytic infundibuloneurohypophysitis: histophathological studies.

A 57-year-old woman presented with 2-year history of polyuria and polydipsia. Hormonal studies revealed almost normal anterior pituitary function and central diabetes insipidus. Magnetic resonance imaging showed thickening of the pituitary stalk and enlargement of the neurohypophysis without high intensity of the posterior lobe on T1-weighted images, which were compatible with lymphocytic infundibuloneurohypophysitis. Transsphenoidal biopsy was done and histological examination disclosed moderate fibrosis and lymphocytic infiltration not only in the posterior pituitary, but also in the adjacent anterior pituitary part of the gland. The lymphocytes both in the anterior and posterior pituitary were mainly T cells that were positive for UCHL 1, CD 3, and CD 8. Immunofluorescence of frozen tissue detected immunecomplex deposition in small vessels and the interstitium. These findings suggested that allergic reactions may play an important role in the pathogenesis of lymphocytic infundibuloneurohypophysitis.

CD3 Complex↗
PubMed1998

Downsizing of an HIV-cell fusion inhibitor, T22 ([Tyr5,12, Lys7]-polyphemusin II), with the maintenance of anti-HIV activity and solution structure.

T22 ([Tyr5,12,Lys7]-polyphemusin II) has been shown to have strong anti-human immunodeficiency virus (HIV) activity comparable to that of 3'-azido-2',3'-dideoxythymidine (AZT). T22, an 18-residue peptide amide, takes an antiparallel beta-sheet structure that is maintained by two disulfide bridges. Herein we synthesized several shortened analogs of T22 in order to search for a more suitable lead compound. A 14-residue analog having one disulfide bridge, TW70 (des-[Cys8,13, Tyr9,12]-[D-Lys10, Pro11]-T22), was found to have highly potent activity comparable to that of T22, and to take an antiparallel beta-sheet structure similar to that of T22. This indicates that the molecular size of T22 can be reduced without loss of activity or significant change in the secondary structure, and that TW70 may represent a novel lead compound. Furthermore, modifying the N-terminal alpha-amino group of TW70 with a fluoresceinthiocarbamoyl group, and the epsilon-amino group of D-Lys8 at the turn portion with a 5-aminopentanoyl group remarkably increased the selectivity index (50% cytotoxic concentration/50% effective concentration).

Amino Acid Sequence↗
PubMed1998

Coronary risk factors in acute Kawasaki disease: correlation of serum immunoglobulin levels with coronary complications.

BACKGROUND: To determine the usefulness of the IgG z-score (age and sex-standardized serum IgG level) before intravenous gamma globulin therapy (IVGG) in predicting the occurrence or severity of coronary complications in Kawasaki disease (KD). METHODS: A case-control study of clinical and laboratory findings with 88 children in the early stage of acute KD who received IVGG (100 or 200 mg/kg for 2-5 days) therapy. Of these, 20 cases had persistent coronary arterial lesions (small aneurysm, moderate aneurysm or large aneurysm persisting more than 1 month). The controls comprised 68 children with no coronary aneurysms or transient small aneurysm only observed within 1 month after the onset of KD. The association between serum levels of immunoglobulin G (IgG). IgM, IgA as well as other coronary risk factors previously reported and the occurrence of the coronary arterial lesions was evaluated using logistic regression analysis. RESULTS: After adjustment for age, gender, total IVGG dose before the 9th illness day and other traditional coronary risk factors, the odds ratio for the persistent coronary aneurysm associated with lower serum IgG z-score (< -0.7485 vs > or = -0.7485), was 30.3 (95% confidence interval, 3.8-243.2). Furthermore, the serum IgG z-score was inversely correlated with the severity of the coronary arterial lesion. CONCLUSIONS: The IgG z-score before IVGG therapy in the early stage of KD provides useful information on the risk factors for persistent coronary aneurysm and is a novel, additional indicator for therapy to prevent the coronary complications in acute KD.

Case-Control Studies↗
PubMed1997

A case of Kawasaki disease with coronary artery aneurysms documenting Yersinia pseudotuberculosis infection.

A case of a 5-year-old boy who fulfilled all the criteria for Kawasaki disease (KD) was described. He had associated bilateral coronary artery aneurysms. Our study revealed the isolation of Yersinia pseudotuberculosis in stool cultures, and the elevation and seroconversion of the agglutination antibody titres, and hence he was diagnosed as Y. pseudotuberculosis infection-positive. We also demonstrated the positive mitogenic activity of the culture supernatant of the isolated bacterium from the patient and detected Y. pseudotuberculosis-derived mitogen by PCR. This case therefore suggests that Y. pseudotuberculosis might be closely related to the cause of KD.

Angiography↗
PubMed1996

Treatment of children with congenital heart disease and growth retardation with recombinant human growth hormone.

Seven prepubertal short children with congenital heart disease were treated with recombinant human growth hormone (GH). Although complete surgical correction was performed for their heart disease at least 2 years before the start of GH therapy, improvement in growth was less than expected in these children. They received 0.5 IU kg-1 week-1 of GH daily for 2 years or more. The growth rate increased from a mean of 4.3 cm year-1 before treatment to a mean of 7.8 cm year-1 in the first year and to a mean of 6.3 cm year-1 in the second year of treatment. Their mean standardized height improved from -3.41 +/- 0.78 to -2.54 +/- 0.62 after 2 years. The mean height age difference minus the bone age difference became positive in these children. We conclude that recombinant GH increases the growth rate in children with congenital heart disease and prepubertal growth retardation.

Child↗
PubMed1990

[A case of rhabdomyolysis demonstrated by Tc-99m methylene diphosphate scintigraphy].

Technetium-99m phosphate compounds are useful for bone scintigraphy. Furthermore they occasionally demonstrated acute myocardial infarction and myocarditis as positive lesions. Also accumulations in the extraskeletal muscle have been reported using these compounds. This case was a 47-year-old male and had localized rhabdomyolysis, caused by compartment syndrome. We report the usefulness of technetium-99m methylene diphosphonate to diagnose the location of rhabdomyolysis.

Compartment Syndromes↗
PubMed1989

The effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on leukemic cells from chronic B cell leukemia.

It is not clear whether cells from various chronic B cell leukemias including B-chronic lymphocytic leukemia (CLL), CLL in prolymphocytoid transformation (CLL-PLT), B-prolymphocytic leukemia (PLL), and hairy cell leukemia (HCL) simply represent different stages of a single B cell differentiation pathway. Furthermore, it is not known whether cells from any given B cell leukemia are characterized by the same population during the differentiation process. Differentiation of various B cell leukemic cells was induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), and the resulting changes in their morphology, cytoplasmic immunoglobulin (clg), and cytochemistry were evaluated. With respect to peculiar morphological change, i.e. extending long thin processes (spreading) and the appearance of clg, each sample showed different responses. According to these two indices samples were classified into three groups; spread+ clg- samples (one case of CLL-PLT, all HCL), spread+ clg+ samples (one of CLL, one of CLL-PLT), and spread- clg+ samples (a majority of CLL, one of CLL-PLT, and all PLL). Unexpectedly, both CLL and CLL-PLT consisted of heterogenous populations as to the reactivity to TPA. In the process of TPA-induced differentiation in CLL cells, features similar to those of HCL cells were not found. Since three different TPA-induced response patterns were observed in each chronic B cell leukemia type, it was not possible to sequentially assign each of these leukemias along a single B cell differentiation pathway. In order to explain this result, we introduced the hypothesis that these groups might be divided into different lineages in B cell differentiation. Since TPA-induced spreading cells were present in the B cell fraction of normal peripheral blood mononuclear cells, this morphological change should not be associated with malignant transformation.

B-Lymphocytes↗
PubMed1987

[Early combined carcinoma and malignant lymphoma in the stomach associated with tonsillar malignant lymphoma--report of a case].

This report deals with a histologic demonstration of a combined tumor of early signet ring cell carcinoma and lymphoma of the stomach in a 52-year-old Japanese man. The Gastric carcinoma was found by a systemic work up for a tonsillar lymphoma. The relationship between the malignant lymphomas of the stomach and of the tonsil is not clear in this case. The carcinoma and lymphoma of the stomach were both small, and the depth of invasion was localized to the mucosa and submucosa, respectively. The lymphoma was observed just beneath the cancer and was a diffuse, large cell type, and of the same histologic typing as the tonsillar lymphoma. Based on the broader size of the carcinoma, it is considered that the carcinoma probably induced the lymphoma in the stomach. This of an early combined tumor of carcinoma and lymphoma of the stomach is, to our knowledge, the first to be reported in the literature.

Adenocarcinoma, Mucinous↗
PubMed1986

Successful treatment of Diphyllobothrium latum and Taenia saginata infection by intraduodenal 'Gastrografin' injection.

Tapeworm infections are very difficult to cure completely. Thirteen patients with tapeworm infection, seven with Diphyllobothrium latum and six with Taenia saginata, were treated by the introduction of a radio-opaque contrast medium, 'Gastrografin', into the duodenum through a duodenal tube. The whole tapeworm with the scolex was expelled unfragmented within 1 h in eleven cases. One patient expelled a tapeworm 3 days after treatment; the peristalsis of his intestine had been severely disturbed after an attack of cerebral apoplexy. The tapeworm could not be expelled by the remaining patient, probably because she had severe intestinal adhesion. The injection of gastrografin allowed clear visualisation of the tapeworm, the diagnosis of the infection could be confirmed, and the descent of the tapeworm could be observed serially. This treatment had no serious adverse effects in any of out patients.

Adult↗
PubMed1986

Leu 11+ T gamma cell chronic lymphocytic leukemia with partially activated natural killer function and its further activation by recombinant IL2 in vitro.

A patient with T gamma cell chronic lymphocytic leukemia with the Leu 11+ phenotype and novel function of activated natural killer cells is reported. The peripheral blood mononuclear cells of this patient showed large granular lymphocytes by May-Giemsa staining and lamellipodia by scanning electron micrography. Tests on reactivity with monoclonal antibodies showed that most cells were Leu 11+, OKT3-/Leu 1-, OKT4-, OKT8-, Leu 7-, OKM1-, and Tac-. Freshly collected cells lysed not only K562, which is highly sensitive to natural killer cells, but also Raji cells and Daudi cells, which are not. Leu 11+ cells were triggered by recombinant interleukin 2 (rIL2) to proliferate, produce gamma-interferon (gamma IFN), and show enhanced HLA-DR antigen expression, and 30% of the Leu 11+ cells became positive for IL2 receptor antigen (Tac). The spectrum of cytotoxic activity of these cells against target cells was extended by rIL2; after treatment with rIL2, the cells also lysed HeLa cells and even fresh cancer cells. This stimulation also increased the activities of acid phosphatase and tartrate-resistant acid phosphatase of the cells and resulted in the appearance of nonspecific esterase activity. The expanded cell population may represent a neoplasm, but these findings provide information on a novel differentiation stage of activated NK cells.

Aged↗