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Featured researches published by Hirohumi Niwa.


Clinica Chimica Acta | 1982

Radioimmunoassay of serum group I and group II pepsinogens in normal controls and patients with various disorders

Masao Ichinose; Kazumasa Miki; Chie Furihata; Takashi Kageyama; R. Hayashi; Hirohumi Niwa; Hiroshi Oka; Taijiro Matsushima; K. Takahashi

A radioimmunoassay (RIA) for human group I pepsinogens (PgI) in serum was developed, using PgI purified from gastric mucosa. The sensitivity (0.7 micrograms/l) and reproducibility of the assay were satisfactory for clinical use. In normal controls, total serum pepsinogen (T-Pg) level was 58.9 +/- 31.7 micrograms/l (mean +/- SD) (PgI, 43.6 +/- 25.0 micrograms/l; PgII, 15.3 +/- 11.1 micrograms/l). Peptic ulcer cases had elevated T-Pg levels (gastric ulcer, gastroduodenal ulcer and duodenal ulcer, in increasing order of magnitude). T-Pg levels were not useful for diagnosis of peptic ulcer because of a large overlap with normal controls. T-Pg levels were low in patients with gastric polyp and in aged subjects. In these groups, the decrease of PgI was more marked than that of PgII.


Gut | 1977

Outcome of gastric carcinoma detected by gastric mass survey in Japan.

Eizo Kaneko; Toshifumi Nakamura; Noritsugu Umeda; Masayuki Fujino; Hirohumi Niwa

The outcome was studied of gastric carcinoma found in six selected mass survey groups. One-hundred-and-thirty-seven cases of gastric carcinoma were detected and followed-up postoperatively for 16 years at the longest. They consisted of 55 cases of early and 74 of advanced carcinoma with eight cases of unknown depth of involvement. Early carcinoma amounted to 42-6% of the cases with known depth of involvement. The relative five-year and 10-year survival rates calculated by the method of Ederer et al. (1961) in the 137 cases were 0-628 and 0-642, respectively, and those for early carcinoma were 0-959 and 1-016. These survival rates are remarkably high. The five-year survival rate in those who were followed-up after operation for more than five years (83 cases) was 0-554, which is much higher than that of the outpatient cases, who presented themselves for medical advice with some symptoms. The good prognosis is largely explained by a high incidence of early gastric carcinoma in the cases detected in the mass survey. Where methods of screening were concerned, the use of the gastrocamera markedly improved the detection rate of gastric carcinoma.


Clinica Chimica Acta | 1982

Radioimmunoassay of Group II pepsinogen in human serum

Masao Ichinose; Kazumasa Miki; Chie Furihata; Takashi Kageyama; Hirohumi Niwa; Hiroshi Oka; T. Oda; Taijiro Matsushima; K. Takahashi

A new radioimmunoassay (RIA) using a double antibody method for human Group II pepsinogens in serum was developed. (1) Sensitivity of this assay system was of the order of 1 microgram per 1 of serum and optimal assay range was 10 to 50 microgram per 1; (2) no effect of interference of human serum was detected and there was no cross-reaction with human Group I pepsinogens within the optimal assay range; (3) satisfactory results were obtained for both within- and between-assay reproducibility (coefficient of variation was 3.9% and 3.7-15.3%, respectively); (4) the mean (+/- SEM) serum Pg II level in healthy donors was 15.9 +/- 0.7 microgram/l for males and 12.8 +/- 1.3 microgram/l for females; the difference between males and females was statistically significant (p less than 0.05); (5) the mean serum Pg II level in 10 patients with total gastrectomy was 1.2 +/- 0.05 microgram/l. These results suggest that most of Pg II in human serum is derived from the gastroduodenal system.


Clinica Chimica Acta | 1978

Human fetal organ alkaline phosphatases

Kazumasa Miki; Toshitsugu Oda; Hiroshi Suzuki; Hirohumi Niwa; Yasuo Endo; Shiro Iino; Jun Miyazaki; Kazuyuki Hirano; Mamoru Sugiura

The properties of human fetal alkaline phosphatase (ALP) have been compared with those of purified human adult hepatic and intestinal ALPs. The ALPs from different human fetal organs were divided into two groups. One terminated universal type was presented in fetal liver, spleen, adrenal, kidney, lung, heart, pancreas, thymus and bone, and was similar to adult hepatic-type ALP. The other terminated intestinal type was presented in fetal intestine and meconium and was similar to adult intestinal ALP. The activity of human fetal intestinal ALP increased markedly with the advance of intra-uterine life during fetal development, and that of human fetal thymus ALP increased slightly.


Gastrointestinal Endoscopy | 1983

New ultrasonic laparoscope for diagnosis of intraabdominal diseases

Yasuhiko Ohta; Kenji Fujiwara; Yuzuru Sato; Hirohumi Niwa; Hiroshi Oka

In abdominal ultrasonic examinations, the conventional approach from outside the abdomen cannot provide necessary information when obesity, ribs, or intraluminal gas interfere with the transmission of the ultrasound. Intraabdominal scanning is sometimes effective in overcoming these problems and has been performed using a rod-type scanner controlled under observation through a separately inserted laparoscope. 1 However, a more practical device combining both a scanner and a laparoscope has long been awaited. We have developed such a system with an ultrasonic laparoscope and a display unit in collaboration with Olympus Optical Co. (Tokyo, Japan) and Aloka Co. (Tokyo, Japan). This article describes the resolution of the scanner, the operability of the scope, and the value of this system in the diagnosis of intraabdominal diseases.


Life Sciences | 1984

Effect of an intracellular calcium antagonist (TMB-8) on carbamylcholine-induced amylase release from dispersed rat pancreatic acini

Masahiro Ikeda; Masatoshi Nagai; Seiji Suzuki; Hirohumi Niwa; Hiroshi Oka; Masayuki Fujino; Hiroshi Suzuki

During 10-min incubation with increasing concentrations of carbamylcholine (carbachol), amylase release from dispersed rat pancreatic acini increased, became maximal at 2 X 10(-6)M and then decreased. In the concentration range of 10(-7)M to 10(-4)M, 8-(N,N-diethylamino)-octyl 3,4,5-trimethoxybenzoate hydrochloride (TMB-8) caused a dose-dependent inhibition of amylase release induced by a submaximal concentration of carbachol. No inhibitory effect was observed on basal and secretin-stimulated amylase release. TMB-8 showed a significantly greater ability of blocking the action of carbachol than verapamil and diltiazem. TMB-8 could reverse the submaximal stimulation of amylase release caused by supramaximal concentrations of carbachol to a maximal stimulation, while verapamil and diltiazem could not. These results confirm the hypothesis that mobilization of intracellular calcium is the primary step in the action of carbachol on pancreatin acinar cells and contributes to the submaximal secretory response of acinar cells induced by high concentrations of carbachol.


Clinica Chimica Acta | 1982

Potential peptic activity of pepsinogen of human gastroduodenal mucosa determined by fluorescent microassay method using succinyl albumin

Kazumasa Miki; Masao Ichinose; Chie Furihata; Hirohumi Niwa; Hiroshi Oka; T. Oda; Taijiro Matsushima

Pepsinogen level, expressed as the potential peptic activity of pepsinogen was determined by a fluorescent microassay using succinyl albumin as substrate, in biopsy specimens from the gastroduodenal mucosa of 95 subjects. The following results were obtained: (1) pepsinogen level in the gastric mucosa becomes progressively higher from pylorus to corpus (p less than 0.001); (2) pepsinogen level in the gastroduodenal mucosa of duodenal ulcer was significantly higher than that of normal mucosa or gastric ulcer (p less than 0.001); (3) the difference in pepsinogen level between the gastric mucosa with and without intestinal metaplasia was statistically significant (p less than 0.01); (4) the correlation between the histology of gastric glands and pepsinogen level was fundic gland greater than intermediate gland greater than pyloric gland (p less than 0.001).


Gastrointestinal Endoscopy | 1982

Upper gastrointestinal mass survey with panendoscopy in a workplace

Kazumasa Miki; Yoji Hirayama; Masao Ichinose; Hirohumi Niwa; Hiroshi Oka; Toshitsugu Oda

We performed a mass survey using a thin forward-viewing gastroscope (Olympus GIF-P2) as a secondary examination of 449 persons from 3457 employees who had undergone the first step of the screening with photofluorography. Comparing these results with those obtained in the mass survey of 1976 and 1977, in which the lateral-viewing gastrocamera, GT-PA2, was employed for the second step of the screening in 372 of 3548 persons examined, we arrived at the following conclusions: (1) the thin forward-viewing gastroscope for mass survey permits accurate diagnosis not only of gastric lesions but also of bulbar lesions; (2) there was no significant difference between the two mass surveys in the rate of discovery of gastric lesions, but gastric ulcer scars were detected at higher rate when using the gastrocamera; and (3) few lesions were noted in cases with an incompletely filled bulb; gastric erosions, especially prepyloric, were noted with bulbar deformity.


Life Sciences | 1983

Effect of secretin on protein phosphorylation in dispersed acini from rat pancreas.

Masahiro Ikeda; Seiji Suzuki; Hiroshi Oka; Hirohumi Niwa; Masayuki Fujino

Dispersed acini from rat pancreas, incubated in the presence of KH2(32)PO4 to steady state 32P incorporation into cellular proteins, were exposed to secretin. 32P incorporated into selected proteins, separated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, reached a plateau by 150 min. Effect of secretin on amylase release, cellular cyclic AMP levels and protein phosphorylation was then examined. Stimulation of amylase release was apparent with 10(-10)M and was maximal with 10(-7)M by 10 min incubation. Almost maximal increase in cellular cyclic AMP levels and 32P incorporation into selected proteins was also observed with 10(-7)M secretin by 10 min in the presence of 10 mM theophyllin. Both secretin (10(-8)M) and dibutyryl cyclic AMP (10(-3)M) induced the phosphorylation of similar proteins analyzed by counting 32P content in each peptide band after SDS gel electrophoresis. Addition of cyclic AMP (10(-6)M) to homogenates of acini also augmented 32P incorporation from [gamma-32P]ATP into similar proteins. These results indicate that secretin enhances protein phosphorylation in pancreatic acinar cells and cyclic AMP may mediate the action of secretin on protein phosphorylation.


Gastroenterologia Japonica | 1979

Endoscopic analysis on the growth of early gastric carcinoma

Eizo Kaneko; Takashi Nakamura; Masayuki Fujino; Noritsugu Umeda; Hirohumi Niwa

SummaryEarliest endoscopic appearance and its subsequent changes were studied in 41 cases of early gastric carcinoma where gastrocamera photographs were available for detailed analysis over the period from three months up to 10 years.The earliest appearance of polypoid carcinoma was a small area of nodularity, and that of carcinoma with mucosal depression was patchy reddening. Both types of carcinoma were thought to occur initially as a lesion without mucosal elevation or depression (IIb). In carcinoma with shallow mucosal depression (IIc and IIc-+III), there were cases believed to have remained intramucosal for an extremely long period of several years, whereas, inpolypoid carcinoma (IIa and I), the growth seemed to be more rapid.In the cases with ulcer within the carcinomatous lesion, healing of the ulcer was confirmed in 37%, and “malignant cycles” were observed in 21 %.Malignant transformation of gastric ulcer was suggested in one case with linear ulcer.

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Takashi Nakamura

Tokyo Institute of Technology

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T. Oda

University of Tokyo

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