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Biomedical subjects

K Sumii

Publications and source records attributed to K Sumii.

At least 73 records · Page 4Linked to original sources
PubMed1997

Effects of octreotide, a somatostatin analogue, on gastric function evaluated by real-time ultrasonography.

BACKGROUND: Somatostatin exerts inhibitory effects on physiological functions in the gastrointestinal tract. The actions differ, however, depending on the test meal, dose, and other factors. AIMS: To determine by use of ultrasonography and scintigraphy the effect of a somatostatin analog, octreotide, on gastric emptying and antral contraction. SUBJECTS: Twenty healthy men; mean age 23.9 years METHODS: Subjects were studied for 7 days, once after subcutaneous injection of octreotide, 50 microg, 5 min before the ingestion of a test meal and once after subcutaneous injection of placebo. Ten subjects received a liquid meal, 10 others received a solid meal. With the liquid meal, gastric emptying was measured 15 min after its ingestion and antral contraction was measured for 15 min by ultrasonography. With the solid meal, gastric emptying was measured both by ultrasonography (n = 10) and by simultaneous scintigraphy (n = 6), with antral contraction measured by ultrasonography for 5 h after ingestion of the meal. RESULTS AND CONCLUSIONS: Octreotide given with a liquid or solid meal inhibited gastric emptying in healthy subjects. A significant suppression of antral contraction occurred only with a solid meal.

Adult↗
PubMed1997

Reduced incidence of Helicobacter pylori infection in young Japanese persons between the 1970s and the 1990s.

Although the incidence of gastric carcinoma in Japan has declined in the past several decades, there is no information about trends in helicobacter pylori infection. The purpose of the study was to clarify trends in H. pylori infection and in histologic gastritis in young Japanese subjects evaluated between 1975 and 1978 (the 1970s) versus 1991 and 1994 (the 1990s). The prevalence of H. pylori infection and the grade of gastritis in biopsy specimens were evaluated in 173 young Japanese without localized lesions in the upper gastrointestinal tract. Findings in 75 specimens obtained from subjects in the 1970s were compared with those of 98 specimens obtained from subjects in the 1990s. The prevalence of H. pylori infection in the 1970s (54.7%) was significantly higher than that in the 1990s (28.6%) (p < 0.01). The grade of inflammation and the prevalence of both mucosal atrophy and intestinal metaplasia also were significantly higher in the 1970s than in the 1990s (p < 0.01 and p < 0.05). Our data thus show a trend toward a reduced prevalence of H. pylori infection and of histologically apparent gastritis (especially atrophic gastritis). This decrease may be linked to the reported decline of gastric carcinoma in Japan.

Adolescent↗
PubMed1997

The usefulness of gastric mass screening using serum pepsinogen levels compared with photofluorography.

Chronic atrophic gastritis, which is though to be a high risk for gastric cancer, can be diagnosed by serum pepsinogen levels. We compared the usefulness of the measurement of pepsinogen levels and indirect photofluorography as indicators of gastric cancer in a mass screening involving 5,620 Japanese subjects (mean age: 60.1 years old; male : female = 2,268:3,352) in 1991 and 1992. Subjects with a serum pepsinogen I level below 30 micrograms/liter or a pepsinogen I/II ratio below 2.0 were considered to be at high risk of gastric cancer. The incidence of gastric cancer and the ratio of early cancers detected by pepsinogen levels (0.12%, 4/7) were similar to those detected by photofluorography (0.11%, 4/6). Our results showed that mass screening using pepsinogen levels was as useful as indirect photofluorography for the detection of gastric cancer in Japan. In addition, our results showed that the sensitivity of gastric mass screening was increased when the measurement of serum pepsinogen levels was combined with photofluorography.

Female↗
PubMed1997

Effect of Helicobacter pylori eradication on subsequent development of cancer after endoscopic resection of early gastric cancer.

Although epidemiological studies strongly suggest an association between gastric cancer and Helicobacter pylori infection, there has been no clinical report indicating that cure of the infection prevents cancer. We conducted a nonrandomized H. pylori eradication trial in patients whose gastric cancer was removed by endoscopic resection (ER). We investigated the effect of treatment on the histopathology of the gastric mucosa, as well as on the incidence of metachronous gastric cancer during the long-term clinical and endoscopic follow-up. One hundred and thirty-two patients with early gastric cancer underwent ER and had H. pylori infection. Sixty-five (group A) were treated with omeprazole and antibiotics to eradicate the infection, and 67 (group B) were not. All patients were followed for 2 years post ER. After eradication treatment in group A, the disappearance of neutrophil infiltration in the antrum and body of the stomach was observed as was a decrease of the severity of intestinal metaplasia. Endoscopy after ER detected no new gastric cancers in these patients. After 3 years of follow-up, 6 (9%) of the 67 patients in group B had a new early-stage, intestinal-type gastric cancer endoscopically diagnosed. The above results suggest that H. pylori eradication may improve neutrophil infiltration and intestinal metaplasia in the gastric mucosa and inhibit the development of new carcinomas. This finding should be confirmed in a randomized, controlled trial.

Adult↗
PubMed1997

Cyclic GMP-dependent protein kinase regulates the L-type calcium current in rat ventricular myocytes.

This study aimed to elucidate the mechanism of cyclic granosine monophosphate (cGMP)-dependent protein kinase (PK-G) regulation of the L-type Ca2+ channel current (ICa(L) in young rat ventricular myocytes using whole-cell voltage clamp with internal perfusion. ICa(L) was usually elicited from a holding potential (HP) of -40 mV. Stimulated ICa(L) (by 2 microM isoproterenol) was inhibited to the basal level by internal perfusion with 50 nM PK-G (activated by 8Br-cGMP, 0.1 microM). Basal ICa(L) (non-stimulated through the cyclic adenosine monophosphate (cAMP)/PK-A pathway) was also inhibited to various degrees (large, medium, or small) by internal application of PK-G (25 nM). The average inhibition was 42.1%, and there were no differences in the inhibition during development. The inhibition by PK-G was blocked by the PK-G substrate peptide (300 microM) and by heart-inactivation of PK-G. The inhibited ICa(L) was reversed by ISO (seven of eight cells). When an HP of -80 mV was used, the inhibition produced by PK-G was much less. The inhibitory effects of PK-G were not mediated by activating phosphodiesterases or protein phosphatases, but most likely by a direct phosphorylation of the Ca2+ channel or associated regulatory protein. The inhibitory effect of PK-G may be explained by a balance between the activities of PK-A and PK-G in regulating the slow Ca2+ channels at two separate sites.

Animals↗
PubMed1996

Inhibition of L-type calcium current in rat ventricular cells by the tyrosine kinase inhibitor, genistein and its inactive analog, daidzein.

Effects of genistein, a specific inhibitor of tyrosine kinase, on the L-type Ca2+ channels were examined in freshly isolated young (days 10-18) rat ventricular cells using the whole-cell patch-clamp technique. Bath application of genistein decreased the L-type Ca2+ current [I(Ca(L))] in a concentration-dependent manner. The maximal inhibition of I(Ca(L)) was about 40% (attained at concentrations above 100 microM); the concentration for half-inhibition (IC50) was 11 microM. The effect of genistein (applied for about 5 min) was poorly reversible after washout for up to 5 min. The potential for half-inhibition (Vh) of the steady-state inactivation curve was shifted in the negative direction by 7 mV (at 100 microM) by genistein, and the slope factor was also slightly changed; the activation curve was not affected. Daidzein, which is structurally related to genistein, but has little inhibitory effect on tyrosine kinase activity (of the EGF receptor), unexpectedly had almost the same inhibitory effect on I(Ca(L)). These observations suggest two possibilities for modulation of I(Ca(L)) in rat ventricular cells by genistein: (a) phosphorylation of the slow Ca2+ channels by tyrosine kinase; and (b) direct inhibition of the slow Ca2+ channels (i.e. independent of inhibition of tyrosine kinase activity).

Action Potentials↗
PubMed1996

Effects of pirenzepine on omeprazole-induced gastrin gene expression in rat antral tissues.

Pirenzepine has inhibitory effects on gastrin secretion both in vivo and in vitro. The aim of this study was to determine the mechanism responsible for the suppression of omeprazole-induced hypergastrinemia that occurs with pirenzepine treatment. The effects were measured in rats treated with oral omeprazole plus intraperitoneal pirenzepine or saline once daily for seven days in the antrum. The serum gastrin level increased significantly by more than sixfold with omeprazole treatment; additional treatment with pirenzepine suppressed this increase by 48%. Pirenzepine treatment did not change the level of gastrin mRNA but significantly increased the level of somatostatin mRNA. Combination treatment with omeprazole plus pirenzepine significantly decreased the gastrin mRNA level to half and significantly increased the somatostatin mRNA level up to 1.4-fold of the levels achieved with omeprazole treatment alone. These results suggest that the stimulatory effect of omeprazole on gastrin synthesis is partially blocked by pirenzepine via mediation of somatostatin synthesis in the antrum.

Actins↗
PubMed1996

Effects of pirenzepine on omeprazole-induced hypergastrinemia and acid suppression in peptic ulcer patients.

Omeprazole effectively suppresses acid secretion, resulting in the long-term elevation of intragastric pH and serum gastrin level. Pirenzepine has been reported to inhibit gastrin secretion. This study was carried out to examine the effects of additional pirenzepine treatment on the hypergastrinemia and gastric acid suppression induced by omeprazole. Concentrations of serum gastrin and plasma somatostatin were measured in 28 peptic ulcer patients before treatment, after omeprazole treatment (20 mg/day) for 2 weeks, and after omeprazole and pirenzepine (100 mg/day) treatment for 2 weeks. The acid inhibitory effect of pirenzepine treatment in addition to omeprazole was evaluated by 24-h intragastric pH measurement in six healthy volunteers. Serum gastrin level was increased significantly, to 2.4-fold the pretreatment level, by omeprazole treatment. Additional treatment with pirenzepine suppressed serum gastrin level to 0.6-fold the omeprazole-treatment level. The serum somatostatin level was not altered significantly either by omeprazole treatment or by omeprazole and pirenzepine treatment. In healthy volunteers whose pH 3 holding time on 24-h intragastric pH monitoring was 70% by omeprazole treatment, omeprazole and pirenzepine treatment markedly increased the pH 3 holding time, to 89%. These findings suggest that pirenzepine is useful in reducing the undesirable effects of omeprazole-induced hypergastrinemia, i.e., the excessive trophic effect of omeprazole on the acid-secreting part of the stomach and the overstimulation of acid secretion. The additional pirenzepine treatment is also effective in suppressing acid secretion.

Adult↗
PubMed1996

Developmental changes in beta-adrenergic and muscarinic modulations of Ca2+ currents in fetal and neonatal ventricular cardiomyocytes of the rat.

Developmental changes of the beta-adrenergic and muscarinic modulations acting on the slow Ca2+ channels in rat ventricular cardiomyocytes were investigated using Ba2+ as the charge carrier (IBa(L)). Single cardiomyocytes from fetal and neonatal rats were freshly isolated, and currents were recorded by whole-cell voltage clamp in Na(+)-free, K(+)-free external solution. Basal current densities showed a large increase between fetal days 15 and 18, and a small decrease after fetal day 20. The ability of isoproterenol (ISO, 1 microM) to enhance IBa(L) increased dramatically between fetal days 18 and 20, and remained almost constant thereafter during the neonatal period. The ability of forskolin (FOR, 10 microM) to stimulate IBa(L) also increased markedly between fetal day 18 and neonatal day 1. Carbachol (CCh), in a dose-dependent manner, reversed the stimulation of the IBa(L) produced by ISO in neonatal cardiomyocytes. The IC50 values for CCh inhibition of IBa(L) was almost the same on all neonatal days tested (neonatal days 1, 5 and 10). The results indicate that there are developmental changes in beta-adrenergic modulation of IBa(L) in the late fetal period, including a large jump in sensitivity to ISO on about fetal day 19. These findings are consistent with the steep increase in number of beta-adrenergic receptors that occurs between fetal days 18 and 20 (Kojima, Sperelakis & Sada, 1990a: Kojima, Ishima, Taniguchi, Kimura, Sada & Sperelakis, 1990C).

Adrenergic beta-Agonists↗
PubMed1996

Evidence that endogenous GRP in rat stomach mediates omeprazole-induced hypergastrinemia.

To investigate the physiological role of endogenous gastrin-releasing peptide (GRP) in regulating the release of gastrin, we evaluated the response of intragastric pH, gastrin, and GRP after omeprazole treatment in rats. A significant elevation of the plasma level of GRP (P < 0.01) and a significant reduction of the antral content of GRP (P < 0.05) were observed after the administration of 100 mg/kg omeprazole. The antral content of GRP was significantly decreased 12 h after omeprazole administration and thereafter gradually returned to control levels. Peak values for intragastric pH and plasma GRP were observed 3 h after omeprazole administration and before the peak of serum gastrin. The bombesin antagonist [D-Phe6]-bombesin-(6,13)-methyl ester significantly inhibited gastrin release after omeprazole treatment (P < 0.05). These observations indicate that omeprazole-induced inhibition of acid secretion stimulates the release of GRP and suggest that the secretion of GRP induced by omeprazole may stimulate the secretion of gastrin, at least in the early phase.

Animals↗
PubMed1996

Helicobacter pylori infection is the major risk factor for atrophic gastritis.

OBJECTIVE: To evaluate the association of both Helicobacter pylori (Hp) infection and advancing age with increased prevalence of atrophic gastritis. METHODS: Two hundred and thirty-eight subjects who had no esophagitis, peptic ulcers, or malignancies in the upper gastrointestinal tract were divided into three groups according to age: group A, < 30 yr; group B, 30-49 yr; group C, > or = 50 yr. Two biopsy specimens were obtained from the lesser curvature of the antrum and two from the anterior and posterior walls of the fundus to assess the degree of gastritis and histological evidence of Hp infection. Hp infection was evaluated by Giemsa staining and serum IgG antibodies. Serum gastrin (SG) and pepsinogen (PG) were determined by radioimmunoassay. RESULTS: In all age groups, the prevalence of atrophic gastritis was significantly more common in subjects with evidence of Hp infection. In Hp-positive subjects, the prevalence of atrophic gastritis increased with advancing age. Atrophic gastritis was extremely rare, regardless of age, in Hp-uninfected patients. SG increased, and PG I and the PG I:II ratio decreased with age in Hp-positive subjects. This trend was not apparent in Hp-negative subjects. CONCLUSION: Our results suggest that Hp infection is a stronger predictor than advancing age for atrophic gastritis.

Adult↗
PubMed1996

[Clinical analysis on the course and prognosis of patients with Crohn's disease].

We analyzed 66 cases (47 males and 19 females) of Crohn's disease at Hiroshima University hospital from September 1975 to October 1994 to clarify the course and prognosis of Crohn's disease. The age at onset was 21.1 +/- 7.3 years old (mean +/- SD), terms between onset and diagnosis were 21.5 +/- 33.0 months (mean +/- SD) and observation period was 65.5 +/- 44.6 months (mean +/- SD). Sites of lesion were 18 ileum, 41 ileocolon and 7 colon. Thirty-one cases, 20 cases of which had intestinal obstruction, underwent surgical operation (12 ileum types, 18 ileocolic types, 1 colon type). The cumulative probability of surgery at one, five and ten years after onset of symptoms were 12.1%, 28.8% and 56.9%, respectively. As for cumulative probability of surgical operation at one, five and ten years after diagnosis were 25.8%, 36.7% and 74.4%, respectively. Results of the cumulative probability of surgery by anatomical involvement indicated that the ileum type had a statistically significantly higher risk than other types. In each analysis compliance to nutritional therapy was also an important prognostic factor. Overall, our results indicated that the site of lesion and the compliance to nutritional therapy were important factors which have an effect on the course and prognosis of Crohn's disease patients.

Adolescent↗
PubMed1996

[Clinicopathologic evaluation on colorectal laterally spreading tumor (LST)].

Clinicopathologic characteristics of 92 colorectal laterally spreading tumors (LST) endoscopically or surgically resected were examined. Lesions were macroscopically classified into two categories according to their surface structure :(1) granular type (G type, 47 lesions), (2) flat type (F type, 45 lesions). The size (maximum diameter) of G type lesions was 24.7 +/- 11.3 mm (Mean +/- SD) and that of F type lesions was 14.2 +/- 7.4 mm. The size of G type lesions was significantly larger than that of F type lesions (p < 0.01). Among G type lesions, cancerous lesion was present in 2 (25.0%) of 8 lesions 10-14 mm in diameter, 2 (22.2%) of 9 lesions 15-19 mm in diameter and 19 (63.3%) of 30 lesions more than 20mm in diameter. Regarding F type lesions, cancerous lesion was present in 15 (46.9%) of 32 lesions 10-14 mm in diameter, 4 (80.0%) of 5 lesions 15-19 mm in diameter and 8 (100%) of 8 lesions more than 20mm in diameter. The incidence of carcinoma in F type lesions was higher than that in G type lesions irrespective of size. F type lesions with carcinoma showed a trend toward a higher frequency of submucosal invasion and F type lesions with adenoma revealed tendency of showing severe atypia in comparison with G type lesions. The adenomatous component of LST showed a tubulo-villous architecture in 13 (28.3%) of 46 G type lesions, however none of F type lesions had a tubulo-villous component. These results indicated that clinicopathologic characteristics of F type are obviously different from G type. Furthermore, F type had a higher malignant potential than G type and is thought to have a more important role as a precursor of colorectal carcinoma than G type.

Adenocarcinoma↗
PubMed1996

Effect of N-feruloyl tyramine (an analogue of tyramine) on inwardly rectifying potassium channel in frog ventricular myocytes.

Electrophysiological effects of N-feruloyl tyramine (NFT), an analogue of tyramine, on potassium currents in frog ventricular myocytes were examined using single-channel recording and whole-cell voltage clamp technique. Extracellular application of NFT induced a concentration-dependent decrease of macroscopic inward rectifier potassium current (iK1) with ID50 of 198 microM, while tyramine (100 microM) was ineffective in producing an inhibitory effect on iK1. NFT reduced the mean open time of iK1 to 1.3 ms from 3.1 ms in control without affecting the amplitude of single-channel conductance. It is indicated that boi containing NFT produces a prolongation of the plateau phase caused by the suppression of inwardly rectifying K channel. Thus, this prolongation may induce an increase in the inflow of Ca ions, which in turn leads to a positive inotropic effect.

Animals↗
PubMed1995

Long openings of calcium channels in fetal rat ventricular cardiomyocytes.

Whole-cell and single-channel Ca2+ currents (ICa) of single fetal (12-18 days) and neonatal (1-10 d) rat ventricular myocytes were recorded using patch clamp techniques. Whole-cell ICa density increased markedly during the fetal period and remained almost constant during the neonatal period. In cell-attached patch recordings (with 110 mM Ba2+ in the pipette), the L-type Ca2+ channels, observed on both fetal d-12 and neonatal d 5, had the same conductance (23 pS). On fetal d-12, many relatively long openings were observed in addition to brief openings, whereas on neonatal d-5, long openings were less observed and brief openings dominated. Therefore, long openings of the Ca2+ channels occur in early development in rat heart cells, similar to that reported for chick hearts [7, 8]. The increase of the whole-cell current amplitude observed during development may be due to an increase in available channel number.

Age Factors↗
PubMed1995

Famotidine, a histamine-2-receptor antagonist, inhibits the increase in rat gastric H+/K(+)-ATPase mRNA induced by intravenous infusion of gastrin 17 and histamine.

We examined the effects of gastrin and histamine on rat gastric H+/K(+)-ATPase, the enzyme responsible for H+ secretion, gene expression in vivo. Gastrin 17 (G 17) or histamine dihydrochloride (histamine) was continuously infused through the femoral vein of anesthetized rats. Gastric H+/K(+)-ATPase mRNA levels were measured using northern blot analysis. Infusion of G 17 and histamine increased the H+/K(+)-ATPase mRNA level significantly compared with basal control level or vehicle control level (P < 0.01). However, pretreatment with famotidine, a potent histamine-2 (H2)-receptor antagonist, inhibited the increase of rat gastric H+/K(+)-ATPase mRNA following G 17 and histamine infusion. These findings indicate that both histamine and G 17 increase expression of H+/K(+)-ATPase mRNA by activating H2 receptor on the parietal cell.

Actins↗