Biomedical subjects

Minoru Okumura

Publications and source records attributed to Minoru Okumura.

9 recordsLinked to original sources

PubMed2006

Concentrations of arsenic in brackish lake water: application of tristimulus colorimetric determination.

The evaluation of a simple and rapid tristimulus colorimetric method for the determination of arsenic in brackish waters and its application to brackish water samples taken from brackish Lake Nakaumi are described. The determinations of arsenic in brackish water samples were made satisfactorily independent of sample salinity. By applying this method to lake water samples, the distributions and behaviors of arsenic in the lake and their controlling factors were clarified, such as seasonal variations of arsenic and the effect of a typhoon.

Journal Article↗

PubMed2006

Increased epithelial cadherin expression among Japanese intestinal-type gastric cancers compared with specimens from American patients of European descent.

The different patterns of gastric cancer in the Far East and West have evolved to the extent that it has been suggested that the disease in Japan is biologically less aggressive than in the West. We studied paraffin-embedded, formalin-fixed tissue blocks from Japanese patients and American patients of European descent who had undergone gastrectomy for gastric cancer not involving the gastroesophageal junction. Specimens were staged (T stage), graded (Lauren classification), and biomarker expression (epithelial cadherin [E-cadherin], c-erbB2, Ki67, and p53) was quantified using immunohistochemistry without knowledge of the country of origin. E-cadherin was expressed in 49 per cent of malignant cells from Japanese specimens compared with 27 per cent of malignant cells from American specimens (P = 0.04). The expression of E-cadherin on diffuse cancers from the two countries was similar (34.4 in Japanese vs 41.5 in American, P = 0.92). E-cadherin expression, however, was significantly higher among intestinal cancers from the two countries: 56.3 per cent of cells from intestinal or mixed cancers from Japan (n = 32) expressed E-cadherin compared with 22.2 per cent of American specimens (n = 12; P = 0.008).-c-erbB2 was expressed on a higher proportion of malignant cells from American specimens (30% vs 22%; P = 0.20). E-cadherin expression, a favorable prognostic factor, is more common in Japanese intestinal-type gastric cancer not involving the gastroesophageal junction. If the biology of gastric cancer in the Far East is less aggressive than that in the United States, it is likely that treatments need to be individualized.

Adenocarcinoma↗

PubMed2005

A simple and rapid in situ preconcentration method for trace ammonia nitrogen in environmental water samples using a solid-phase extraction followed by spectrophotometric determination.

A simple and rapid in situ preconcentration method for the spectrophotometric determination of trace ammonia nitrogen in environmental water samples has been developed based on solid-phase extraction using a small column packed with octadecyl group-bonded silica gel (Sep-Pak C18 cartridge). A water sample was taken into a graduated syringe for easy and simple operation and prevention of contamination immediately after sample collection. Ammonia in the sample was reacted with hypochlorite and thymol to be converted into indothymol blue; then the formed indothymol blue was collected as an ion pair between indothymol blue and tetrabutylammonium ion on a Sep-Pak C18 cartridge. The indothymol blue on the cartridge was stable for 4 days. The retained indothymol blue was easily eluted with a mixture of methanol and 0.01 mol/l sodium hydroxide solution. The color intensity due to the indothymol blue was spectrophotometrically measured at 725 nm. The proposed method was successfully applied to environmental water samples such as river water.

Ammonia↗

PubMed2005

The liquid-liquid extraction using hydrophilic solvents occluded to an oil-adsorbent as an organic phase: extraction of 8-quinolinolato complexes of alkaline earth metals into tetrahydrofuran.

In order to use a hydrophilic solvent as an organic phase in liquid-liquid extraction by retaining it to a solid support, the occlusion and desorption of nine hydrophilic solvents, such as methanol, to three kinds of commercially available oil-adsorbent were examined. The combination of tetrahydrofuran and WOSEP made by fibrous polypropylene was finally selected, and was subjected to the extraction of alkaline Earth metals with 8-quinolinol. It was proved that Mg2+, Ca2+, and Sr2+ ions could be successfully extracted into the tetrahydrofuran phase in the form of 8-quinolinolato complexes, which could not be extracted into CHCl3.

Journal Article↗

PubMed2004

A simple and sensitive method for the determination of hydroxylamine in fresh-water samples using hypochlorite followed by gas chromatography.

A new and simple method for the determination of hydroxylamine in environmental water, such as fresh rivers and lakes using hypochlorite, followed by its gas choromatographic detection, has been developed. A glass vial filled with sample water was sealed by a butyl-rubber stopper and aluminum cap without head-space, and then sodium hypochlorite solution was injected into the vial through a syringe to convert hydroxylamine to nitrous oxide. The head-space in the glass vial was prepared with 99.9% grade N2 using a gas-tight syringe. After the glass vial was shaken for a few minutes, nitrous oxide in the gas-phase was measured by a gas chromatograph with an electron-capture detector. The dissolved nitrous oxide in the liquid-phase was calculated according to the solubility formula. The proposed method was applied to the analysis of fresh-water samples taken from Iu river and Hii river, flowing into brackish Lakes Nakaumi and Shinji, respectively.

Journal Article↗

PubMed2004

A simple in situ visual and tristimulus colorimetric method for the determination of trace arsenic in environmental water after its collection on a mercury(II)-impregnated paper.

A simple in situ visual and tristimulus colorimetric method for the determination of trace arsenic in environmental water after collecting arsenic on a test paper impregnated with mercury(II) bromide and rosaniline chloride by its reduction aeration has been developed. The color development on the test paper is based on the formations of AsH(HgBr)2 (yellow) and/or As(HgBr)3 (brownish yellow) by a reaction between mercury(II) bromide and arsine (AsH3), which is produced through the reduction of As(III) (arsenite ion) and/or As(V) (arsenate ion) in a sample solution. To a sample solution, potassium iodide, tin(II) chloride, zinc sand and 4 ml of 6 M hydrochloric acid solution were added successively. The liberated arsine was collected on the test paper. The yellow or brownish-yellow color intensity on the test paper was measured by a tristimulus colorimeter and also by a visual method. The established method is applicable to the determination of arsenic in environmental water sample such as river, brackish, and seawater types.

Journal Article↗

PubMed2003

Early gastric cancer with Krukenberg tumor and review of cases of intramucosal gastric cancers with Krukenberg tumor.

A 47-year-old woman was admitted because of hypermenorrhea. Transvaginal ultrasonography revealed an ovarian tumor and myoma uteri, and total hysterectomy with bilateral salpingo-oophorectomy was performed. Histology revealed signet-ring cell carcinoma in the right ovary. In order to find out the primary site of this tumor, gastroendoscopy was performed after the operation, and showed a IIc lesion in the lower body of the stomach; biopsy specimens showed signet-ring cell carcinoma similar to that in the right ovary. Total gastrectomy revealed that the lesion was an early gastric cancer confined to the mucosa, but there was lymphatic invasion slightly beneath the muscularis mucosa, with regional lymph node metastasis. In the light of a review of the seven cases of early gastric cancer with Krukenberg tumor previously reported, lymphatic metastasis seemed to be the most likely pathway of ovarian metastasis in early gastric cancers.

Female↗

PubMed2002

Retroperitoneal lymphangioma with a duodenal lesion in an adult.

A multilocular-cystic and cavernous, retroperitoneal tumor was found in a 40-year-old man whose past medical history was unremarkable. On admission, he complained of a large and still growing intra-abdominal mass associated with dull pain and a low-grade fever. Laboratory findings revealed leukocytosis and C-reactive protein elevation, compatible with inflammation of the tumor. Percutaneous aspiration of the tumor was performed under transabdominal ultrasonographic guidance, and continuous drainage of fluid from within the tumor ameliorated his symptoms. From preoperative examinations, including radiological imaging, fluid aspiration, and endoscopy with biopsy, a diagnosis of retroperitoneal lymphangioma was made. Laparotomy revealed extensive adhesions between the tumor and both the duodenum and the pancreatic head. A pancreaticoduodenectomy was therefore performed. At 3-year follow-up, there was no sign of recurrence. Retroperitoneal lymphangioma is an uncommon disorder, and the cavernous type is extremely rare. The duodenal lesion was an important feature of the present case, and endoscopic biopsy of this lesion facilitated precise preoperative diagnosis of retroperitoneal lymphangioma.

Adult↗

PubMed2002

A simple and rapid in situ preconcentration method using solid-phase extraction for the determination of dissolved manganese in brackish lake water samples.

A simple and rapid in situ preconcentration method for the determination of dissolved manganese in environmental waters has been developed based on solid-phase extraction using a Sep-Pak C18 cartridge. Manganese in water samples, which was taken into a graduated syringe to easily perform the operation for collecting manganese at sampling sites, was converted into a stable complex with 4-(2-pyridylazo)resorcinol (PAR) at pH 10 immediately after sample collection. The formed Mn-PAR complex was collected by a Sep-Pak C18 cartridge, which was packed with C18-bonded silica. The complex was stable in the Sep-Pak C18 cartridge for at least one month. The retained complex was quantitatively eluted with 0.5 M hydrochloric acid. The manganese was determined by graphite-furnace AAS. The proposed method was successfully applicable to brackish lake water samples to investigate the behavior of dissolved manganese in brackish lakes.

Adsorption↗