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Biomedical subjects

H Mashima

Publications and source records attributed to H Mashima.

At least 37 records · Page 2Linked to original sources
PubMed1995

The effect of lansoprazole treatment on the healing and relapse of peptic ulcer and serum levels of IgG anti-Helicobacter pylori antibody.

In the present study, the effects of short-term treatment with lansoprazole on healing and recurrence of peptic ulcer were investigated. Complete healing (change to the S2 stage) after 3 or 4 weeks of treatment with lansoprazole was observed in 9.9% of gastric ulcers and 38.3% of duodenal ulcers. Complete healing was observed after 3 or 4 weeks of treatment with lansoprazole in gastric ulcers and was significantly related to the serum titer of IgG anti-Helicobacter pylori antibodies. This was not the case in duodenal ulcers. Complete healing after 6 or 8 weeks of treatment with lansoprazole was not dependent on serum levels of IgG anti-H. pylori antibodies. Short-term treatment by lansoprazole did not affect serum levels of IgG anti-H. pylori antibodies immediately after the end of lansoprazole treatment, but significantly reduced serum levels of IgG anti-H. pylori antibodies were found 9 months after treatment.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Conversion of amylase-secreting rat pancreatic AR42J cells to neuronlike cells by activin A.

When AR42J cells, an amylase-secreting pancreatic exocrine cell line, were treated with activin A, cells extended neuritelike processes, and, concomitantly, amylase-containing vesicles disappeared. Immunofluorescence and immunoelectron microscopy revealed that these processes had neurite-specific cytoskeletal architectures: neurofilaments and microtubule bundles with cross-bridges of microtubule-associated protein 2. In addition to such morphological changes, activin-treated cells exhibited a marked increase in cytoplasmic free calcium concentration in response to depolarizing concentration of potassium. Moreover, activin-treated AR42J cells expressed mRNA for alpha 1 subunit of the neuroendocrine/beta cell-type voltage-dependent calcium channel. In naive AR42J cells, a sulfonylurea compound, tolbutamide, did not affect free calcium concentration, while it induced a marked elevation of free calcium in activin-treated cells. Single channel recording of the membrane patch revealed the existence of ATP-sensitive potassium channel in activin-treated cells. These results indicate that activin A converts amylase-secreting AR42J cells to neuronlike cells. Given that pancreatic endocrine cells possess neuronlike properties and express ATP-sensitive potassium channel as well as neuroendocrine/beta cell-type voltage-dependent calcium channel, activin treatment of AR42J cells may provide an in vitro model system to study the conversion of pancreatic exocrine cells to endocrine cells in islets.

Activins↗
PubMed1994

An unusual presentation of spontaneous pneumoperitoneum secondary to the rupture of a gas-containing pyogenic liver abscess: report of a case.

We describe a rare case of spontaneous pneumoperitoneum secondary to the rupture of a gas-containing pyogenic liver abscess in a 59-year-old man. The patient was diagnosed as having a hollow viscus perforation based on a sudden onset of acute abdominal pain along with radiological evidence of bilateral subphrenic feee air (pneumoperitoneum), and underwent an emergency laparotomy. Contrary to expectations, the surgery revealed no perforations of the hollow viscus, but instead a ruptured liver abscess at the dome of the right hepatic lobe was identified associated with suppurative peritonitis. To the best of our knowledge, such a case of spontaneous pneumoperitoneum secondary to the rupture of a gas-containing liver abscess is extremely rare.

Abdomen, Acute↗
PubMed1994

A case of hepatocolic fistula after percutaneous drainage for a gas-containing pyogenic liver abscess.

We describe a rare case of gas-containing pyogenic liver abscess which penetrated the adjacent colon, forming a hepatocolic fistula, after percutaneous transhepatic abscess drainage (PTAD) had been performed. To the best of our knowledge, this is the first report of hepatocolic fistula associated with a gas-forming liver abscess in a diabetic patient, with radiological and surgical confirmation of the fistula.

Colonic Diseases↗
PubMed1994

Activin A: negative regulator of amylase secretion and cell proliferation in rat pancreatic acinar AR42J cells.

Activin A, a member of the transforming growth factor-beta supergene family, exists in secretory granules of non-B-cells of rat pancreatic islet (H. Yasuda, K. Inoue, H. Shibata, T. Takeuchi, Y. Eto, Y. Hasegawa, N. Sekine, Y. Totsuka, T. Mine, E. Ogata, and I. Kojima. Endocrinology 133: 624-630, 1993). Because functions of exocrine pancreas are influenced by hormones in pancreatic islet, it is possible that activin A affects the function of pancreatic acinar cells. To examine this possibility, we studied the effects of activin A on amylase secretion and DNA synthesis in AR42J cells. In these cells, dexamethasone (Dx) induces increases in secretory organelles and secretion of amylase (C. D. Logsdon, J. Moessner, J. A. Williams, and I. D. Goldfine. J. Cell Biol. 100: 1200-1208 1985). Activin A did not change the rate of amylase release by itself nor affect the cholecystokinin-stimulated amylase release from Dx-treated differentiated AR42J cells. However, when activin A was added together with Dx, activin A inhibited Dx-induced increase in amylase content in a dose-dependent manner. In the presence of 1 nM activin A, the effect of Dx was abolished. In the absence of Dx, amylase content of the cells was also reduced by activin A in a dose-dependent manner. The maximum inhibitory effect was obtained by 10 nM activin A, and at this concentration amylase content became undetectable. In addition, activin A potently inhibited DNA synthesis as assessed by [3H]thymidine incorporation.(ABSTRACT TRUNCATED AT 250 WORDS)

Activins↗
PubMed1994

Healing of chronic gastric ulcer depends on gastric mucosal prostaglandin synthesis.

In the present study, the role of endogenous prostanoid synthesis in gastric mucosa in the healing of chronic gastric ulcers was investigated. Nineteen patients were divided into two groups in accordance with healing state after one month of treatment with cimetidine only: "healed group" and "unhealed group". Biopsy specimens taken from the mucosa around the ulceration (damaged gastric mucosa) and at a distance from the ulceration (normal gastric mucosa) at endoscopy prior to treatment were homogenized, and the mucosal prostanoid synthesis was determined using [14C]arachidonic acid. The mean value of prostaglandin E2 synthesis in the normal gastric mucosa of the healed group was 60% higher than in that of the unhealed group, but the difference was not significant. However, prostaglandin E2 synthesis in the damaged gastric mucosa of the healed group was 117% higher than in that of the unhealed group. The same tendency was observed for prostaglandin D2 and 6-keto prostaglandin F1 alpha synthesis as for prostaglandin E2. In our study it was demonstrated that there is a good correlation of prostaglandin synthesis in the damaged mucosa with healing of chronic gastric ulceration. Furthermore, our study indicated that prostaglandin synthesis, especially in damaged mucosa, might be important in the healing of gastric ulceration.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

[Clinical study on the effect of continuous transarterial infusion chemotherapy of CDDP for metastatic liver tumors].

Thirteen patients with unresectable liver tumors, including 7 colorectal cancers, 5 gastric cancers, and 1 breast cancer, were treated by intraarterial continuous infusion of CDDP using an implantable reservoir. The catheter was placed by direct insertion at laparotomy (7 cases) or through the inferior epigastric artery (6 cases). The clinical antitumor effects were evaluated by CT-scan or ultrasonography. One CR, 6 PR, and 6 NC were observed among the thirteen patients, respectively. The response rate for all cases was 53.8%, which is evidently higher than that of previously reported "one shot" transarterial MMC and 5-FU infusion chemotherapy. Since this treatment method induces little side effects, it can be maintained in outpatient clinics. Thus, we concluded that this treatment could be useful to improve the quality of life of patients with unresectable liver tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

[Intra-arterial chemotherapy with granulocyte colony-stimulating factor for breast cancer before surgical treatment].

Intra-arterial chemotherapy (IAC) for far advanced breast cancer is now performed as a routine adjuvant chemotherapy before surgical treatment. However, the following problems remain unsolved; (1) serious adverse reactions such as myelosuppression, (2) unsuccessful insertion of catheter into the internal thoracic artery, and (3) long waiting-period from IAC to surgical treatment. The present studies were conducted to evaluate the utility of a one-route IAC, in which the subclavian artery alone is used, and the efficacy of granulocyte colony-stimulating factor (G-CSF). There was no significant difference in the antitumor effect between the patients with two-route IAC, in which both internal thoracic artery and subclavian artery are used, and the patients with one-route IAC. Administration of G-CSF in combination with IAC reduced both the frequency and the severity of IAC-induced side effects. G-CSF administration during IAC was more effective than after IAC. G-CSF prevented IAC-induced myelo-suppression and/or accelerated recovery from this complication and thus reduced significantly the waiting-period before surgical treatment.

Breast Neoplasms↗
PubMed1991

[Trans-arterial infusion chemotherapy through the inferior epigastric artery for malignant abdominal tumors without laparotomy].

A new technique of intra-arterial catheterization through the inferior epigastric artery using a subcutaneously-implanted silicon reservoir was tried for arterial infusion chemotherapy in patients with cancer located in specific lesions. Eight surgically uncontrollable tumors, consisting of 6 hepatic metastasis, one surgically incurable gastric cancer and one recurrent rectal cancer, were treated by continuous arterial infusion of cis-diamminedichloroplatinum (CDDP) using this new method. Clinical antitumor effect was evaluated by CT scan, sonography or operation. CR, PR and NC were observed in 3, 3 and 2 patients, respectively. No significant difference in CDDP levels in serum was found between CR plus PR and NC cases. Since this method can be done without laparotomy, more patients may benefits from arterial infusion chemotherapy.

Adult↗
PubMed1991

[Studies on pruritus in obstructive jaundice cases with special references to serum bile acid fractions].

About, 22 cases with pruritus and 18 cases without pruritus of obstructive jaundice, serum bile acids were analysed quantitatively by high performance liquid chromatography (HPLC) before and after biliary decompression for the study on the relationship between pruritus and non-pruritus group. Analysis was also carried out on 11 cases with normal liver function as the control group. And 15 kinds of bile acids were as followed: unconjugates (ursodeoxycholic: UDCA, cholic: CA, chenodeoxycholic: CDCA, deoxycholic: DCA, lithocholic acid: LCA), glycine conjugates (Gly-UDCA, Gly-CA, Gly-CDCA, Gly-DCA, Gly-LCA) and taurine conjugates (Tau-UDCA, Tau-CA, Tau-CDCA, Tau-DCA, Tau-LCA). Data was analysed by t-test statistically. [I] Before biliary decompression (1) No significant difference was observed between the pruritus group and non-pruritus group about total bile acid level, total unconjugates level and CA/CDCA ratio. (2) On total glycine-conjugates level the pruritus group was significantly lower than the non-pruritus group, that level was about 3/5. Similarly on Gly-CA level was about 2/3, on Gly-CDCA level was about 1/2. (3) By contraries on total taurine-conjugates level the pruritus group was significantly high as compared with the non-pruritus group, that level was about two times. Similarly on Tau-CA and Tau-CDCA levels were about two times. (4) From there results on glycine/taurine ratio (G/T) of total bile acids pruritus group was significantly low as compared with the non-pruritus group, that level was about 1/3. Similarly on G/T ratio of CA level was about 2/5 and on G/T ratio of CDCA was about 1/3. (5) As for various unconjugates, UDCA level was significantly high in pruritus group as compared with non-pruritus group. [II] After biliary decompression No significant difference was shown in the composition of serum bile acids between the pruritus group and the non-pruritus group. These studies showed that the pruritus in the obstructive jaundice cases stood in a certain relation to the increase of taurine-conjugates, especially taurine-conjugated CA and taurine-conjugated CDCA, moreover increase of unconjugated UDCA.

Aged↗
PubMed1984

Modeling of cardiac muscle contraction based on the cross-bridge mechanism.

A mathematical model was developed for the cardiac muscle contraction, assuming that the attachment and detachment cycle of the cross-bridge is activated by the internal calcium concentration and the rate constant of the cycle depends on the sliding velocity of myofilaments. The inputs of the model are the rates of calcium release and uptake, while the output is the tension curve of the muscle. The variables are factored into a series of realizable functions and most constants were determined from the dynamic constants for the tetanic contraction of frog ventricular muscle at 20 degrees C. Using this model, the calcium transient curve as well as the change in the number of cross-bridges in each state of the cycle during a given experimental twitch tension curve was calculated with a PDP 11/60 computer, by selecting the input parameters so that the output curve fit the experimental curve. When the twitch tension was increased by increasing initial muscle length, the rate of calcium release increased and that of uptake decreased. At higher external calcium concentrations, the similar changes in the input parameters were observed. In the presence of 5 X 10(-6) g/ml adrenaline the duration of activation was markedly prolonged, while the rates of calcium release and uptake show little change.

Animals↗
PubMed1984

Left ventricular function and muscle mechanics in hypertrophied rabbit heart.

Ventricular contractile performance was studied in relation to wall muscle mechanics in isolated rabbit left ventricles during pressure-overloaded hypertrophy. The isovolumic pressure-volume relation of the hypertrophied ventricle (LVH) shifted to the left and upward from the normal control (NC) (P less than 0.001), but calculated wall stress at each normalized circumferential length decreased in LVH. The pressure-ejection rate relation, determined accurately by velocity control technique, could be adequately approximated by a hyperbola. In LVH, the maximum pressure (Po) was larger (154.3 +/- 17.0 mmHg), whereas the maximum ejection rate (Vej max) was smaller (13.7 +/- 4.2 ml/s, P less than 0.001) than those for NC (127.7 +/- 23.3 mmHg and 22.3 +/- 5.7 ml/s, respectively). The pressure-stiffness relation was linear in both groups, but the vertical axis intercept increased, indicating increased resting stiffness in LVH. Ventricular volume stiffness vs. the mean wall stress relationship of LVH shifted upward, whereas the normalized wall muscle stiffness vs. the mean wall stress relationship of LVH showed a smaller slope. Thus the hypertrophied ventricle can maintain its pumping ability at normal or augmented levels with depressed contractile function of the wall muscle.

Animals↗
PubMed1984

Force-velocity relation and contractility in striated muscles.

For skeletal muscle, the physiological meaning of Hill's hyperbolic force-velocity equation and the factors affecting it, such as the active state, method of velocity measurement and mode of stimulation, have been discussed. After the development of the sliding filament theory, Hill's equation was generalized to all partially activated isometric tensions and the meaning of Hill's dynamic constants was interpreted from the kinetic analysis of the cross-bridge cycle. In cardiac muscle, determination of the precise force-velocity relation was almost impossible, but most difficulties were overcome by tetanizing the cardiac muscle. As a result, the force-velocity properties of cardiac muscle were confirmed to be very similar to those of skeletal muscle. The maximum shortening velocity under no load, v0, was once used as an index of myocardial contractility which is insensitive to muscle length, but it is now believed that at least at shorter lengths, v0 may vary with muscle length and degree of activation. As new approaches, studies on sarcomere dynamics by the laser diffraction method, observation of calcium transient and pressure-velocity measurement in whole ventricle have been introduced.

Animals↗
PubMed1980

Ca binding of isolated cardiac nexus membranes related to intercellular uncoupling.

Nexus membranes were isolated from cardiac muscles of guinea pig or ox. It was confirmed by autoradiography that Ca2+ was actually bound with the nexus, and by atomic absorption spectroscopy that bound Ca increased extensively at [Ca2+] higher than 10(-6) to 10(-5) M and showed the dose-response relationship against [Ca2+].

Adenosine Triphosphatases↗
PubMed1979

Intracellular distribution of calcium in cardiac muscles studied by electron microscope autoradiography.

The intracellular distribution of calcium was investigated by 45Ca electron microscope autoradiography in the frog or rat ventricular muscle and guinea pig papillary muscle. The muscle was incubated for 30 min in 45Ca-Ringer's solution or high Ca solution in which 1/10--1/20 of Ca was replaced with 45Ca. The distribution of developed silver grains sensitized by the 45Ca (45Ca grains) was found to be 38% in the mitochondria, 43% in the myofibrils and 19% in the other regions (8% in the cytoplasma and 11% in the various membranous structures) in the frog muscle cell incubated in the 45Ca-Ringer's solution. After electrical stimulation (10 Hz, 5 min), the distribution was 22% in the mitochondria, 53% in the myofibrils and 25% in other regions. Similar results were obtained after high K stimulation in the frog ventricular muscles and after electrical stimulation in high Ca solution in guinea pig papillary muscles. Following the addition of 1 X 10(-6) g/ml adrenaline into the incubating solution, the grain distribution in guinea pig papillary muscles did not show significant change but the distribution in myofibril decreased after electrical stimulation, while it increased in the mitochondria. Longitudinal localization of 45Ca grains along the myofibril was also examined and it was a general tendency throughout all animals examined that the grain density at the A band and near the Z band decreased after electrical stimulation, while it increased at the I band and, especially, at the A-I junction.

Animals↗