Publications by authors named "Kazuhiro Ogawa"

Crack-free nanocellular graphenes are attractive materials with extraordinary mechanical and electrochemical properties, but their homogeneous synthesis on the centimeter scale is challenging. Here, a strong nanocellular graphene film achieved by the self-organization of carbon atoms using liquid metal dealloying and employing a defect-free amorphous precursor is reported. This study demonstrates that a Bi melt strongly catalyzes the self-structuring of graphene layers at low processing temperatures.

View Article and Find Full Text PDF

Objective: We previously reported that dickkopf WNT signaling inhibitor 3 (DKK3) would modulate malignant potential of oral squamous cell carcinoma (OSCC) via activating Akt. Recently, cytoskeleton associated protein 4 (CKAP4) functions as receptor of DKK3, which activates Akt in esophageal squamous cell carcinoma, but its expression and function in OSCC were unclear.

Methods: We studied DKK3 and CKAP4 protein expression in OSCC tissue and investigated the correlation between protein expression and clinical data.

View Article and Find Full Text PDF

Objective: To clarify whether antiparkinsonian drugs contribute to nocturnal sleep disturbances in patients with Parkinson's disease (PD).

Background: Although the major antiparkinsonian drugs L-dopa and dopamine agonists (DAs) have been found to affect sleep, little is known about the effects of specific drugs on sleep in PD patients.

Methods: The study participants consisted of 112 PD patients (median age 72.

View Article and Find Full Text PDF

The pinning effect is useful for restraining austenite grain growth in low alloy steel and improving heat affected zone toughness in welded joints. We propose a new calculation model for predicting austenite grain growth behavior. The model is mainly comprised of two theories: the solute-drag effect and the pinning effect of TiN precipitates.

View Article and Find Full Text PDF

A woman in her 80s was admitted to our hospital on account of jaundice, abnormal liver function tests, and leukocytosis. She was diagnosed with adult T-cell leukemia on the basis of the presence of anti-human T-cell leukemia virus type I (HTLV-I) and the results of flow cytometric analysis of peripheral blood. She also showed lung consolidation and cavitation, and a sputum smear and culture revealed cryptococcal infection.

View Article and Find Full Text PDF

Background: The choice of surgical or non-surgical treatments for osteochondritis dissecans (OCD) of the humeral capitellum is still controversial. The purpose of this study was to assess the efficacy of fragment fixation for OCD of the humeral capitellum.

Methods: We reviewed 28 patients with OCD of the humeral capitellum after a mean follow up of 17 months.

View Article and Find Full Text PDF

Intracellular heme concentrations are maintained in part by heme degradation, which is catalyzed by heme oxygenase. Heme oxygenase consists of two structurally related isozymes, HO-1 and HO-2. Recent studies have identified HO-2 as a potential oxygen sensor.

View Article and Find Full Text PDF

Heme oxygenase consists of two structurally related isozymes, heme oxygenase-1 and and heme oxygenase-2, each of which cleaves heme to form biliverdin, iron and carbon monoxide. Expression of heme oxygenase-1 is increased or decreased depending on cellular microenvironments, whereas little is known about the regulation of heme oxygenase-2 expression. Here we show that hypoxia (1% oxygen) reduces the expression levels of heme oxygenase-2 mRNA and protein after 48 h of incubation in human cell lines, including Jurkat T-lymphocytes, YN-1 and K562 erythroleukemia, HeLa cervical cancer, and HepG2 hepatoma, as judged by northern blot and western blot analyses.

View Article and Find Full Text PDF

Heme oxygenase (HO) catalyzes physiological heme degradation and consists of two structurally related isozymes, HO-1 and HO-2. Here we show that HO-2-deficient (HO-2(-/-)) mice exhibit hypoxemia and hypertrophy of the pulmonary venous myocardium associated with increased expression of HO-1. The hypertrophied venous myocardium may reflect adaptation to persistent hypoxemia.

View Article and Find Full Text PDF

In addition to the chief function of erythropoietin (Epo) in promoting erythropoiesis, some other roles have been found in the brain and uterus. We have reported that signalling pathways of Epo and Epo receptor (EpoR) are involved in the tumourigenesis of ovarian and uterine cancers. To determine whether Epo plays a similar role in other malignancies, we studied the expression of Epo in several malignant human cell lines.

View Article and Find Full Text PDF

Heme oxygenase 1 (HO-1) catalyzes heme breakdown, eventually releasing iron, carbon monoxide, and bilirubin IXalpha. HO-1 is induced by its substrate heme and various environmental factors, which represents a protective response against oxidative stresses. Here we show that hypoxia represses HO-1 expression in three human cell types but induces it in rat, bovine, and monkey cells, indicating the inter-species difference in the hypoxic regulation of HO-1 expression.

View Article and Find Full Text PDF

One of the most well-characterized symptoms of lead poisoning is porphyria. The biochemical signs of lead intoxication related to porphyria are delta-aminolevulinic aciduria, coproporphyrinuria, and accumulation of free and zinc protoporphyrin in erythrocytes. From the 1970s to the early 80s, almost all of the enzymes in the heme pathway had been purified and characterized, and it was demonstrated that delta-aminolevulinic aciduria is due to inhibition of delta-aminolevulinate dehydratase by lead.

View Article and Find Full Text PDF

In 1998, a amovie entitled "A Civil Action" was released. The movie described the Woburn case, begun in 1982 and concluded in 1990, one of the most famous cases of trichloroethylene pollution. In a small town near Boston, twelve children died of leukemia, which seemed attributable to trichloroethylene contamination of the drinking water.

View Article and Find Full Text PDF
[Heme metabolism in stress response].

Nihon Eiseigaku Zasshi

January 2002

Heme and its metabolism fulfill significant roles in many homeostatic and adaptative reactions. For example, heme (protein) senses oxygen concentration to regulate hypoxia response genes such as erythropoietin, and free heme, a proxidant, controls levels of several oxidative stress response proteins as well as that of a few enzymes in the heme metabolic pathway. Heme oxygenase (HO) is the key enzyme in heme catabolism, which degrades heme to Fe, CO, and biliverdin.

View Article and Find Full Text PDF