101
|
Shiba Y, Mizumoto A, Inatomi N, Haga N, Yamamoto O, Itoh Z. Stimulatory mechanism of EM523-induced contractions in postprandial stomach of conscious dogs. Gastroenterology 1995; 109:1513-21. [PMID: 7557133 DOI: 10.1016/0016-5085(95)90638-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
BACKGROUND & AIMS EM523, a motilin agonist, is intended to be used as a gastroprokinetic during the postprandial period, but the mechanism(s) by which EM523 stimulates postprandial contractions in the stomach has not been studied before. The aim of this study was to examine the mechanism of contraction-stimulating activity by EM523 in fed dogs. METHODS Contractile activity in the gastric antrum of 5 dogs was monitored using a long-term implanted force transducer and measured by integrating the area under the curve. Test materials were continuously infused or injected intravenously. RESULTS EM523 (1-30 micrograms/kg) induced a dose-dependent increase in fed-type contractions. EM523-induced contractile activity was partially inhibited by atropine, hexamethonium, dopamine, 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, and substance P antagonist. Atropine-resistant and EM523-induced contractions were further inhibited by 5-HT3 receptor antagonist and substance P antagonist, and the combined use of the two antagonists completely eliminated the atropine-resistant and EM523-induced contractions. CONCLUSIONS EM523-induced contractions in the fed stomach are quite different from phase III contractions in the fasted state and are mediated partially through the cholinergic pathway. The noncholinergic pathway involves 5-HT3 and neurokinin 1 receptors.
Collapse
|
102
|
Yamamoto O, Oikawa S, Katoh N. Enzyme-linked immunosorbent assay for serum apolipoprotein B-100, a major triglyceride-transport protein in dairy cows. Am J Vet Res 1995; 56:1413-7. [PMID: 8585649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
An ELISA was developed to determine serum concentration of apolipoprotein B-100, a major triglyceride-binding protein in very low-density lipoproteins and a putative maker for hepatic lipidosis of dairy cows. Serum apolipoprotein B-100 was prepared electrophoretically, and antibodies to this protein were raised in rabbits. The antiserum prepared was further purified by affinity chromatography, using bovine serum albumin-Sepharose 4B, to remove antibodies to albumin. For the ELISA, addition of 2-mercaptoethanol to the coating buffer (50 mM sodium carbonate, pH 9.6) was required to evaluate apolipoprotein B-100 concentration in serum. The ELISA developed was sensitive (detection limit was 300 to 400 ng/ml of serum) and reliable (coefficients of variance were in the range of 3.3 to 7.6%). By use of the established ELISA, the serum apolipoprotein B-100 concentration was found to be significantly (P < 0.01) lower during the early lactating stage than during other stages of lactation. Reduced hepatic synthesis or secretion of apolipoprotein B-100 during the early lactating stage, together with the excess uptake by the liver of serum nonesterified fatty acids, is suggested to be relevant in the accelerated accumulation of triglycerides in the liver of dairy cows during the periparturient period.
Collapse
|
103
|
Kosuda S, Yokoyama H, Katayama M, Yokokawa T, Kusano S, Yamamoto O. Technetium-99m tetrofosmin and technetium-99m sestamibi imaging of multiple metastases from differentiated thyroid carcinoma. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1995; 22:1218-20. [PMID: 8542909 DOI: 10.1007/bf00800609] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A 79-year-old male with follicular thyroid carcinoma metastasizing to the lung, bone and lymph nodes was subjected to whole-body scintigraphy using technetium-99m tetrofosmin and 99mTc-sestamibi. Both agents delineated the metastatic lesions and the two image qualities were comparable. We believe that 99mTc-tetrofosmin and 99mTc-sestamibi images may be helpful in localizing metastatic foci and substitute for thallium-201 in the follow-up of patients with differentiated thyroid carcinoma.
Collapse
|
104
|
Yamamoto O, Seyama T, Jo T, Terato H, Saito T, Kinomura A. Oral administration of tritiated water (HTO) in mouse. II. Tumour development. Int J Radiat Biol 1995; 68:47-54. [PMID: 7629437 DOI: 10.1080/09553009514550911] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Previously we reported haematopoietic death as an effect of tritiated water (HTO) in drinking water in the concentration range from 5.92 x 10(11) to 1.85 x 10(10) Bq/dm3. In the present study the effects of HTO in a lower concentration range from 9.25 x 10(9) Bq/dm3 (0.240 Gy/day) to 3.70 x 10(8) Bq/dm3 (0.096 Gy/day) are reported. Female (C57BL/6N and C3H/He)F1 mice were maintained on drinking water containing various levels of HTO. Mice survived for > 150 days with a high incidence of tumour development (70 to 80%). In the dose-rate range from 9.25 x 10(9) Bq/dm3 (0.240 Gy/day) to 1.85 x 10(9) Bq/dm3 (0.048 Gy/day) the main cause of death was thymic lymphoma. However, at a dose-rate of 9.25 x 10(8) Bq/dm3 (0.024 Gy/day) the incidence of thymic lymphoma sharply decreased, while the incidence of other tumours increased. The tumour type became more diverse at lower concentrations of HTO. The latent period of tumour development was shorter and the life-shortening effect was more marked by 3H beta-irradiation in this study than b X- or gamma-irradiation reported in other investigations.
Collapse
|
105
|
Motoyama T, Yamamoto O, Iwamoto H, Watanabe H. Fine needle aspiration cytology of primary mediastinal germ cell tumors. Acta Cytol 1995; 39:725-32. [PMID: 7543237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Fine needle aspiration cytology was performed on six patients with malignant mediastinal germ cell tumor: 1 pure seminoma, 1 pure embryonal carcinoma, 1 pure yolk sac tumor and 3 mixed germ cell tumors containing teratoma. Their cytologic features were compared with each other and with the cytologic features of thymoma, which arises commonly in the anterior mediastinum. A definitive cytologic diagnosis could be made only in the cases of seminoma because of its characteristic cytologic features. Cytochemical staining for germ cell alkaline phosphatase was helpful in diagnosing seminoma in the cytologic examination, while the presence of hyaline globule or alpha-fetoprotein immunostaining as the cytologic diagnostic feature of yolk sac tumor were not necessarily found in fine needle aspiration cytology. All epithelial, lymphocytic and mixed type thymomas were easily differentiated from the four types of germ cell tumor examined.
Collapse
|
106
|
Maeda K, Hashimoto M, Koh J, Yamamoto O, Hosoda Y, Morikawa Y. The use of an ileostomy connector to diminish the frequency of defecation prior to ileostomy closure in patients with a pelvic pouch. Surg Today 1995; 25:657-61. [PMID: 7549283 DOI: 10.1007/bf00311445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A new method for allowing stool passage into the pelvic pouch before ileostomy closure to verify the defecation state and diminish stool frequency is reported herein. This was accomplished by fitting an ileostomy connector connecting the proximal and distal openings of the diverting loop stoma. The ileostomy connector was initially in place for 6 h a day, the length of time being gradually increased until it was able to be left in for 24 h a day over a 3-month period. The calculated daily frequency of stools decreased from 24 to 6 or 7 times, and the mean daily frequency immediately after ileostomy closure was 6.5 times. Physiological study also showed an improvement, with squeeze pressure increasing from 35 cmH2O to 116 cmH2O and the maximum tolerated volume increasing from 35 ml before, to 90 ml 3 months following the use of an ileostomy connector. Thus, we conclude that an ileostomy connector may be useful to predict postoperative functional outcome and its complications, and to diminish the frequency of defecation before ileostomy closure in patients with a covering loop stoma.
Collapse
|
107
|
Yamamoto O, Bhawan J, Solares G, Tsay AW, Gilchrest BA. Ultrastructural effects of topical tretinoin on dermo-epidermal junction and papillary dermis in photodamaged skin. A controlled study. Exp Dermatol 1995; 4:146-54. [PMID: 7551562 DOI: 10.1111/j.1600-0625.1995.tb00238.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We examined the effects of daily topical application of 0.05% tretinoin cream on photodamaged Caucasian facial skin by electron microscopy. Specimens obtained pretreatment, after 6 and 12 months of tretinoin therapy (20 patients), and after 6 months of vehicle treatment (5 patients) were compared in a blinded fashion, with special attention to the dermoepidermal junction and papillary dermis. Baseline specimens disclosed various degrees of damage including reduplication of basal lamina, smudging and sparsity of collagen fibers, and nodular arrangement of degenerated microfibrils in the papillary dermis. No significant changes were observed at 6 months in the papillary dermis of either tretinoin-treated or vehicle-treated patients. After 12 months of tretinoin treatment, however, disorganized collagen fibers, which were conspicuous in 11 patients at baseline, were replaced by new well-organized collagen fibers in a wavy pattern in 6 patients. In addition, the amount of nodularly degenerated microfibrillar material decreased in 15 of 18 patients with this finding at baseline. In contrast, no significant change was noted in the number of anchoring fibrils per unit length of the lamina densa. These observations provide further evidence that topical treatment with 0.05% tretinoin produces papillary dermal reconstruction, for which more than 6 months of application were required.
Collapse
|
108
|
Watanabe M, Ozaki T, Hirata Y, Yamamoto O, Niida H, Ueda F, Yoshikuni Y, Kimura K. Mechanism for lowering blood ammonia levels by lactitol. JAPANESE JOURNAL OF PHARMACOLOGY 1995; 67:369-74. [PMID: 7650870 DOI: 10.1254/jjp.67.369] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Lactitol has been reported to decrease the blood ammonia concentration in various experimental hyperammonemia models such as portacaval shunted rats. The mechanism responsible for this lowering of blood ammonia levels was investigated in rats. When lactitol was given orally twice a day for 7 days at doses of 3 and 10 g/kg/day and at half that daily dose on day 8, it significantly decreased the ammonium concentration of the portal blood by 27.3-43.2%, cecal ammonia contents by 49.2-57.6% and the pH of the cecal contents from 6.52 to 5.92-5.54, 4 hr after the final administration. Lactitol also inhibited increases in the portal ammonia concentration induced by the intracecal administration of ammonium acetate (300 mg/kg) 4 hr after the final administration. When lactitol was given orally at bolus doses of 1 and 3 g/kg simultaneously with a charcoal meal, lactitol significantly facilitated small intestinal transit by 12-13%. At a bolus dose of 3 g/kg, given 1 hr before the administration of a charcoal meal into the proximal colon, lactitol significantly facilitated colonic transit by 29.5%. These effects of lactitol were similar to those of lactulose. These findings suggest that lactitol decreases blood ammonia concentration by inhibiting both the production and the absorption of ammonia through reducing intestinal pH and shortening the residence time of intestinal contents in the intestinal tract.
Collapse
|
109
|
Yamamoto O, Bhawan J, Hara M, Gilchrest BA. Keratinocyte degeneration in human facial skin: documentation of new ultrastructural markers for photodamage and their improvement during topical tretinoin therapy. Exp Dermatol 1995; 4:9-19. [PMID: 7757335 DOI: 10.1111/j.1600-0625.1995.tb00216.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We examined epidermal impairment in photodamaged Caucasian skin by light and electron microscopy and observed two types of degeneration of the basal and suprabasal keratinocytes. The first was an electron-lucent degeneration predominantly seen in the periphery of the cells. The marked lucent degeneration occurred in 14% of the basal and suprabasal keratinocytes, predominantly in cells immediately adjacent to melanocytes. In skin specimens with a large number of such damaged keratinocytes, bleb-like keratinocytic protrusions or electron-lucent intercellular structures were also seen. Many vacuolar structures were observed just under the dermoepidermal junction, occupying 9% of the junction length. These structures were produced by herniation of the degenerative portion of the basal and suprabasal keratinocytes, and appeared to be phagocytized by dermal macrophages. The vacuolar alterations in the basal layer and dermoepidermal junction previously reported at the light microscopic level probably represent these intercellular lucent structures, bleb-like protrusions and vacuole-like structures at the electron microscopic level. The second type, dark-staining keratinocytes, probably representing an extensive degenerative process, constituted 4% of the basal and suprabasal keratinocytes. After 12 months of topical tretinoin treatment, dramatic improvement of both degenerative processes of the keratinocytes was noted.
Collapse
|
110
|
|
111
|
Yamamoto O, Matsunaga Y, Shiba Y, Haga N, Sano I, Itoh Z. Inhibition of motilin-induced phase III contractions by pentagastrin in Heidenhain pouch dogs. J Pharmacol Exp Ther 1994; 271:1471-6. [PMID: 7996460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We compared the inhibitory effects of histamine and pentagastrin (PG) on motilin-induced upper gastrointestinal phase III activity in conscious dogs that had surgically prepared Heidenhain pouchs (HP). Contractile activity was measured by means of chronically implanted force transducers, and changes in pH of the perfusate through the HP were monitored simultaneously. Intravenous infusion of PG (4 micrograms/kg-hr) inhibited motilin-induced phase III activity both in the main stomach and in the HP, whereas histamine (40 micrograms/kg-hr) inhibited activity only in the main stomach. Famotidine (0.3 mg/kg, i.v., the dose that completely inhibited gastric acid secretion by PG or histamine) blocked the inhibition of phase III activity induced by histamine but did not affect PG-induced inhibition. L-364,718 (1 mg/kg, i.v.), which had no effect on the PG-induced decrease in the pH of the perfusate lowered by PG, reversed the inhibition of phase III activity by PG in the HP but not in the main stomach. However, L-364,718, when combined with famotidine, potently reversed the PG-induced inhibition of phase III activity both in the main stomach and in the HP. These results show that the inhibitory effect of PG on motilin-induced phase III activity is brought about by two distinctive mechanisms, gastric acid and the cholecystokinin receptors-dependent mechanism, whereas the histamine-induced inhibition is mediated only by gastric acid. In the vagally denervated HP, however, gastric acid is not involved in an inhibitory effect of PG.
Collapse
|
112
|
Furukawa S, Yamamoto O, Tamura T, Masuda Y, Shudo C, Hayashi K, Hirata H. Influence of efonidipine hydrochloride, calcium antagonist on the epithelium of prostates in spontaneously hypertensive rats. J Toxicol Sci 1994; 19:213-7. [PMID: 7884832 DOI: 10.2131/jts.19.4_213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The hypertensive effect on the development of the prostatic abnormality in spontaneously hypertensive rats (SHRs) was examined using Efonidipine hydrochloride, a calcium antagonist. The control SHRs were given a high sodium and potassium diet (SP-diet) alone, and the treated SHRs were given a SP-diet with 0.15% Efonidipine hydrochloride from 8 to 28 weeks of age. The systolic blood pressure (SBP) in the control SHRs increased with age, while the elevation of SBP was significantly prevented in the treated SHRs. Light-microscopically, the prostatic lesion was observed both in the control and treated SHRs. The glandular lumen was narrowed with papillary protrusions, and the epithelium was composed of tall columnar epithelial cells. However, hypertension-induced complications in kidneys and hearts were not observed in the treated SHRs. These results suggested that the prostatic abnormality of SHRs might not be the consequent lesions upon hypertension.
Collapse
|
113
|
Ueda F, Kameda Y, Yamamoto O, Shibata Y. Beta-adrenergic regulation of gap-junctional intercellular communication in cultured rabbit gastric epithelial cells. J Pharmacol Exp Ther 1994; 271:397-402. [PMID: 7525926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The effect of a beta-adrenergic agonist, isoproterenol, on gap-junctional intercellular communication (GJIC) and intracellular cyclic AMP (cAMP) content was investigated in cultured rabbit gastric epithelial cells. Isoproterenol rapidly enhanced GJIC determined by the Lucifer yellow transfer at 10(-6) and 10(-5) M but the effect at 10(-6) M was variable. The enhancement of GJIC by 10(-5) M isoproterenol, which disappeared within 10 or 30 min, was inhibited by a beta blocker, propranolol. Isoproterenol (10(-6) M) greatly increased cAMP at 5 min and much more so at 20 min after its addition. Colforsin (also known as forskolin) and 3-isobutyl-1-methylxanthine (IBMX) enhanced GJIC until 16 and 20 min after their addition, respectively. Both colforsin and IBMX increased the cAMP content by a lesser extent than 10(-6) M isoproterenol. Isoproterenol (10(-5) M) inhibited the GJIC enhanced by colforsin or IBMX. Propranolol abolished the inhibition of GJIC by isoproterenol in the presence of IBMX. Both amiloride, an inhibitor of the Na+/H+ exchanger, and nigericin, a K+/H+ antiporter, inhibited the GJIC enhanced by isoproterenol, IBMX, colforsin and irsogladine. An inhibitor of cAMP-dependent protein kinase A, H-89 (N-[2-((3-(4- bromophenyl)-2-propenyl)-amino)-ethyl]-5-isoquinolinesulfonamide), abolished the enhancement of GJIC by colforsin and IBMX but did not abolish that by isoproterenol.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
114
|
Maeda K, Hashimoto M, Yamamoto O, Koh J, Sakai S, Shiraishi T, Chiba Y, Hosoda Y, Shirato M, Seki T. [A case of fistula-cancer response to arterial chemoembolization]. Gan To Kagaku Ryoho 1994; 21:2341-4. [PMID: 7944475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Arterial chemoembolization was performed three times preoperatively for cancer associated with fistula-in-ano for diminishing the postoperative surgical tissue defect of the perineum. Partial response of the tumor to this treatment was confirmed by computed tomography. A sixty-two-year-old male patient recognized a mass in the perineum one and a half years ago. He had suffered from fistula-in-ano for thirty years. The mass increased its size and formed a tumor in the bilateral buttocks (12 x 9 cm and 9 x 9 cm in diameter). Biopsy specimen showed a moderately differentiated adenocarcinoma. Angiography showed a hypervascular tumor stain. The main feeders to the tumor were the superior rectal artery and bilateral internal iliac artery. Arterial chemoembolization was performed three times through the right and left internal iliac artery with Gelfoam particle. Arterial infusion chemotherapy was added through inferior mesenteric artery and bilateral internal iliac artery with a total 120 mg of adriamycin and 1,500 mg of 5-FU simultaneously. The tumor decreased in size to 44% of the preoperative size by the treatment. A radical operation was performed following the preoperative treatment. Preoperative arterial chemoembolization for cancer associated fistula-in-ano was considered to be helpful for local control.
Collapse
|
115
|
Terato H, Yamamoto O. Hydrated electron-induced inactivation of tyrosinase in aqueous solution by exposure to cobalt-60 gamma-rays. I. Cresolase activity. BIOCHEMISTRY AND MOLECULAR BIOLOGY INTERNATIONAL 1994; 34:295-300. [PMID: 7849640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tyrosinase (0.2 mg/ml of 0.1 M phosphate buffer solution, pH 6.5) which has cresolase and catecholase activities was irradiated with 60Co gamma-rays. The cresolase activity was measured at varying radiation doses under various atmospheric conditions. D0 was found to be 350 Gy in N2-saturated solution. The OH radical has been shown to be the main species involved in radiation-induced enzyme inactivation. However, in this study, OH radical scavengers, t-BuOH and MeOH, had no effect. O2 which acts generally as an enhancer of OH-induced enzyme inactivation also had little effect, but N20 ae aq scavenger, and Cu++ markedly inhibited the inactivation indicating that e aq is the main species involved in inactivating the cresolase activity, reducing Cu++ as the active center.
Collapse
|
116
|
Terato H, Yamamoto O. Hydrated electron-induced inactivation of tyrosinase in aqueous solution by exposure to cobalt-60 gamma-rays. II. Catecholase activity. BIOCHEMISTRY AND MOLECULAR BIOLOGY INTERNATIONAL 1994; 34:301-7. [PMID: 7849641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tyrosinase (0.2 mg/ml) was irradiated with 60Co gamma-rays. The catecholase activity was measured at varying radiation doses under various atmospheric conditions. D0 was found to be 1.25 kGy and hit number to be 2 in N2-saturated solution. OH radical scavengers, t-BuOH and MeOH, had no effect. O2 which is an enhancer of OH-induced enzyme inactivation had little effect. But N2O as a e aq scavenger and Cu++ markedly protected against the inactivation indicating that e aq was the main species to inactivate the enzymatic activity. By Ultrogel chromatography, it was found that the enzymatic activity was lost when this enzyme dissociated into its subunits. Thus, it was concluded that the radiation-induced inactivation was due to the reduction of Cu++ as the active center and the chelater with e aq followed by the dissociation.
Collapse
|
117
|
Maeda K, Hashimoto M, Katai H, Koh J, Yamamoto O, Hosoda Y. Peranal introduction of the stapler in colorectal anastomosis with a double-stapling technique. Br J Surg 1994; 81:1057. [PMID: 7922064 DOI: 10.1002/bjs.1800810744] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
118
|
Yamamoto O, Matsunaga Y, Haga N, Itoh Z. Vagovagal inhibition of motilin-induced phase III contractions by antral acidification in dog stomach. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 267:G129-34. [PMID: 8048525 DOI: 10.1152/ajpgi.1994.267.1.g129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Gastric acidification at pH 1.0 strongly inhibits the spontaneously occurring and motilin-induced phase III contractions in canine and human stomach. In this study, we examined inhibition by gastric acidification in dogs following gastrojejunostomy, truncal vagotomy, and antrectomy. As a result, gastric acidification with 0.1 N HCl solution at pH 1.0 for 30 min at a rate of 1.0 ml/min significantly inhibited motilin-induced phase III activity to 23.5 +/- 5.9% of the control in the normal intact dogs and to 17.2 +/- 3.4% in the gastrojejunostomized dogs. In the antrectomized dogs, gastric acidification did not significantly inhibit the action of motilin (81.7 +/- 10%), but, in the vagotomized dogs, gastric acidification inhibited the action of motilin to 72.0 +/- 4.9%; the inhibition was much weaker than in the intact and gastrojejunostomized dogs but was significant. The duodenal acidification had no effect at all on the action of motilin (94.6 +/- 12.5%) in the gastrojejunostomized dogs. These findings strongly suggest the existence of a vagovagal reflex in the inhibition of motilin-induced phase III contractions by gastric antral acidification, although the involvement of sympathetic regulation cannot be completely ruled out.
Collapse
|
119
|
Matsunaga Y, Yamamoto O, Ueki S, Haga N, Mizusawa F, Mizumoto A, Sano I, Itoh Z. Inhibition of phase III activity by acid in canine stomach. REGULATORY PEPTIDES 1994; 52:61-72. [PMID: 7972933 DOI: 10.1016/0167-0115(94)90022-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Very few phase III activity of the interdigestive migrating contractions (phase III) occurs in the stomach of fasted duodenal ulcer patients. But the mechanism is not well understood. In this study, we studied the effect of gastric and duodenal acidification on the spontaneous phase III activity in the upper gastrointestinal tract of conscious dogs. Gastric and duodenal motor activity in 5 conscious dogs was monitored by means of chronically implanted force transducers. Intragastric pH changes were measured by placing a pH glass electrode in the gastric antrum. Intragastric and intraduodenal acidification was achieved by i.v. infusion of histamine, and by intragastric and intraduodenal instillation of acidic solutions of different pHs. The plasma motilin concentrations were measured by radioimmunoassay. Histamine (40 micrograms/kg/h) inhibited spontaneous phase III activity, but the histamine-induced inhibition was completely prevented by pretreatment with famotidine, a potent histamine H2 receptor antagonist (0.3 mg/kg, i.v.). Intragastric acidification at pH 1.0 strongly inhibited spontaneous phase III activity, but an acidic solution at pH 2.0 had no effect in inhibiting phase III activity. Intraduodenal acidification at pH 1.0 also inhibited spontaneous phase III activity. Histamine injection and gastric and duodenal acidification at pH 1.0 strongly suppressed motilin release. It is concluded that gastric and duodenal acidification at pH 1.0 inhibits the occurrence of the spontaneous phase III activity, and the suppression of endogenous release of motilin due to gastric and duodenal acidification at pH 1.0 is involved in this inhibitory mechanism.
Collapse
|
120
|
Yamamoto O, Matsunaga Y, Haga N, Mizumoto A, Itoh Z. Inhibition of phase III activity by acidifying stomach in vagally denervated and innervated dogs with gastric pouches. Gastroenterology 1994; 106:1533-41. [PMID: 8194699 DOI: 10.1016/0016-5085(94)90407-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND/AIMS Intragastric acidification at pH 1.0 strongly inhibits phase III contractions in the dog, but this mechanism is not well known. We studied the mechanism in conscious dogs. METHODS Vagally denervated and innervated gastric pouch dogs were prepared. Force transducers were chronically implanted on the serosa of the pouch, main stomach, and mid-duodenum. The pH of the perfusate was monitored. RESULTS Administration of histamine (40 micrograms.kg-1.h-1 intravenously [i.v.]) and instillation of acidic saline at pH 1.0, but not pH 2.0, into the main stomach strongly inhibited the motilin-induced (0.1 microgram/kg i.v.) phase III activity in the main stomach and the innervated pouch but did not influence contractions in the extrinsically denervated pouch. Famotidine completely reversed the histamine-induced inhibition of phase III in the main stomach and Pavlov pouch. Acidification of the pouch itself or duodenum at pH 1.0 did not affect contractions in the main stomach and pouch of either type. CONCLUSIONS The mechanism of inhibition of motilin-induced phase III activity by acid in the stomach involves the intact vagovagal reflex, but sympathetic participation is not completely ruled out. The inhibition of motilin-induced phase III activity may originate in the antral mucosa of the stomach.
Collapse
|
121
|
Yamamoto O, Bhawan J. Three modes of melanosome transfers in Caucasian facial skin: hypothesis based on an ultrastructural study. PIGMENT CELL RESEARCH 1994; 7:158-69. [PMID: 7971749 DOI: 10.1111/j.1600-0749.1994.tb00044.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The transfer mechanism of melanosome from the melanocyte into the keratinocyte was investigated in mildly photodamaged Caucasian facial skin by electron microscopy. Three ways of transfer are suggested by our observations. The first mechanism probably occurs through the following process: 1) protrusion and insertion of the thick dendrite of the melanocyte into the basal keratinocyte, 2) formation of sac-dendrite complex in the subnuclear region, 3) digestion and segregation of the enclosed dendrite, 4) formation of the cistern in the paranuclear region, and 5) pinching-off of the melanosomes in single or aggregated form from the tip of the cistern. The second mechanism probably takes place through a membrane fusion between the melanocyte and the keratinocyte. Such a membrane fusion possibly forms a passage way for release of the melanosome from the former cell to the latter. The third mechanism is considered to include exocytosis of the single melanosome from the melanocyte followed by the endocytosis through the formation of coated-pit in the keratinocyte.
Collapse
|
122
|
Ohyama Y, Ozono K, Uchida M, Shinki T, Kato S, Suda T, Yamamoto O, Noshiro M, Kato Y. Identification of a vitamin D-responsive element in the 5'-flanking region of the rat 25-hydroxyvitamin D3 24-hydroxylase gene. J Biol Chem 1994; 269:10545-50. [PMID: 8144641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The 5'-flanking region of the rat vitamin D3 24-hydroxylase (P450cc24) gene was examined and a vitamin D-responsive element (VDRE) responsible for the 1 alpha,25-dihydroxyvitamin D3 (1,25-(OH)2D3) enhancement was identified. Unidirectional deletion analyses of the 5'-flanking region indicated that the region [-167/-102] is involved in vitamin D responsiveness. Further functional analyses showed that the segment [-204/-129] conferred the hormone responsiveness in an orientation-independent manner when it was placed upstream to the heterologous thymidine kinase promoter or the rabbit beta-globin promoter. The segment [-204/-129] contained two direct repeat motifs homologous to other VDREs found in the osteocalcin and osteopontin genes. Synthetic oligonucleotides containing the putative VDRE were used for functional analyses and gel mobility shift assays. The proximal [-151/-137], but not the distal [-169/-155] direct repeat activated the transcription in response to 1,25-(OH)2D3 through the beta-globin promoter. Furthermore, the proximal direct repeat formed a complex with the vitamin D receptor and a nuclear accessory factor(s) from COS cells (or retinoid X receptor) in the presence of 1,25-(OH)2D3. These results indicate that a direct repeat motif, AGGTGAgt-gAGGGCG, located at -151 base pairs upstream in the antisense strand binds to a heterologous dimer consisting of the VDR occupied with 1,25-(OH)2D3 and the nuclear accessory factor and that it plays a critical role in mediating the vitamin D enhancement of the rat P450cc24 gene expression.
Collapse
|
123
|
Abstract
We report a case of a giant cystic cutaneous adnexal hamartoma which showed fibrofollicular units embedded in the stroma with aberrant fat tissue. There were many sebaceous lobules in the fibrofollicular units, and its histologic features were consistent with conventional folliculosebaceous cystic hamartoma. Given the unique clinical history and appearance, this lesion is considered to be a congenital variant.
Collapse
|
124
|
Yamamoto T, Kanno R, Takeda Y, Yamamoto O, Kawamoto Y, Takano M. Crystal Structure and Metal-Semiconductor Transition of the Bi2-xLnxRu2O7 Pyrochlores (Ln = Pr-Lu). J SOLID STATE CHEM 1994. [DOI: 10.1006/jssc.1994.1116] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
125
|
Yamamoto O, Oguchi K, Korematsu M, Hashimoto M, Hosoda Y, Mimura T, Ito K. [New surgical strategy for secondary hyperparathyroidism]. NIHON GEKA GAKKAI ZASSHI 1993; 94:1118-1124. [PMID: 8232186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Extopic parathyroid glands and rudimentary glands which are not detected during initial parathyroidectomy may develop hyperplasia in the future, causing recurrence of hyperthyroidism. We have devised an improved surgical strategy to prevent the recurrence of hyperparathyroidism. The strategy is to dissect all central lymph nodes and fatty tissue according to the procedure of the dissection of thyroid cancer. The upper level of the dissection area is the upper edge of the thyroid cartilage and the lateral level of the dissection includes the lateral edge of the bilateral carotid sheath. Bilateral transcervical thymectomy is always included in this strategy. Upon confirming that more than 4 glands have been removed by intraoperative stamp cytology, total parathyroidectomy is terminated and 80 mg of glands is autotransplanted to the muscle of one forearm. We have performed this operation on 30 patients since 1987. More than 4 glands could be extirpated in every case, and supernumerary glands were detected in 6 cases (7 glands in 1 case and 5 glands in 4 cases). We have had no operative side effects in this series of 30 patients, and we have not experienced any persistent or recurrent hyperparathyroidism after any of these operations.
Collapse
|