Direct vascular actions of quercetin in aorta from renal hypertensive rats

BACKGROUND: Chronic treatment with the dietary flavonoid quercetin is known to lower blood pressure and restore endothelial dysfunction in animal models of hypertension. This study investigated the direct effects of quercetin on vascular response in chronic 2-kidney, 1-clip (2K1C) renal hypertensive rats. The effects of antioxidant vitamin ascorbic acid on the vasoreactivity were also examined. METHODS: 2K1C renal hypertension was induced by clipping the left renal artery; age-matched rats that received sham treatment served as controls. Thoracic aortae were mounted in tissue baths for the measurement of isometric tension. RESULTS: Relaxant responses to acetylcholine were significantly attenuated in 2K1C rats in comparison with sham rats. Quercetin or ascorbic acid augmented acetylcholine-induced relaxation in 2K1C rats, whereas no significant differences were noted in sham rats. The relaxation response to sodium nitroprusside was comparable between 2K1C and sham rats, and sodium nitroprusside-induced relaxation was not altered by quercetin or ascorbic acid in either group. The contractile response to phenylephrine was significantly enhanced in 2K1C rats compared with sham rats. Phenylephrine-induced contraction was inhibited by pretreatment with quercetin or ascorbic acid in 2K1C rats, whereas neither chemical affected responses in sham rats. N(w)-nitro-L-arginine methyl ester markedly augmented the contractile response to phenylephrine in sham rats, whereas no significant differences were observed in 2K1C rats. Quercetin or ascorbic acid did not affect phenylephrine-induced contraction in the presence of N(w)-nitro-L-arginine methyl ester in either 2K1C or sham rats. CONCLUSION: Acute exposure to quercetin appears to improve endothelium-dependent relaxation and inhibit the contractile response, similar to the effect of ascorbic acid in 2K1C hypertension. These results partially explain the vascular beneficial effects of quercetin in renal hypertension.

Effects of Lubiprostone on Pacemaker Activity of Interstitial Cells of Cajal from the Mouse Colon

Lubiprostone is a chloride (Cl-) channel activator derived from prostaglandin E1 and used for managing constipation. In addition, lubiprostone affects the activity of gastrointestinal smooth muscles. Interstitial cells of Cajal (ICCs) are pacemaker cells that generate slow-wave activity in smooth muscles. We studied the effects of lubiprostone on the pacemaker potentials of colonic ICCs. We used the whole-cell patch-clamp technique to determine the pacemaker activity in cultured colonic ICCs obtained from mice. Lubiprostone hyperpolarized the membrane and inhibited the generation of pacemaker potentials. Prostanoid EP1, EP2, EP3, and EP4 antagonists (SC-19220, PF-04418948, 6-methoxypyridine-2-boronc acid N-phenyldiethanolamine ester, and GW627368, respectively) did not block the response to lubiprostone. L-NG-nitroarginine methyl ester (L-NAME, an inhibitor of nitric oxide synthase) and 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ, an inhibitor of guanylate cyclase) did not block the response to lubiprostone. In addition, tetraethylammonium (TEA, a voltage-dependent potassium [K+] channel blocker) and apamin (a calcium [Ca2+]-dependent K+ channel blocker) did not block the response to lubiprostone. However, glibenclamide (an ATP-sensitive K+ channel blocker) blocked the response to lubiprostone. Similar to lubiprostone, pinacidil (an opener of ATP-sensitive K+ channel) hyperpolarized the membrane and inhibited the generation of pacemaker potentials, and these effects were inhibited by glibenclamide. These results suggest that lubiprostone can modulate the pacemaker potentials of colonic ICCs via activation of ATP-sensitive K+ channel through a prostanoid EP receptor-independent mechanism.

Mechanisms of phytoestrogen biochanin A-induced vasorelaxation in renovascular hypertensive rats

BACKGROUND: The plant-derived estrogen biochanin A is known to cause vasodilation, but its mechanism of action in hypertension remains unclear. This study was undertaken to investigate the effects and mechanisms of biochanin A on the thoracic aorta in two-kidney, one clip (2K1C) renovascular hypertensive rats. METHODS: Hypertension was induced by clipping the left renal artery, and control age-matched rats were sham treated. Thoracic aortae were mounted in tissue baths to measure isometric tension. RESULTS: Biochanin A caused concentration-dependent relaxation in aortic rings from 2K1C hypertensive and sham-treated rats, which was greater in 2K1C rats than in sham rats. Biochanin A-induced relaxation was significantly attenuated by removing the endothelium in aortic rings from 2K1C rats, but not in sham rats. Nomega-Nitro-L-arginine methylester, a nitric oxide synthase inhibitor, or indomethacin, a cyclooxygenase inhibitor, did not affect the biochanin A-induced relaxation in aortic rings from 2K1C and sham rats. By contrast, treatment with glibenclamide, a selective inhibitor of adenosine triphosphate-sensitive K+ channels, ortetraethy-lammonium, an inhibitor of Ca2+-activated K+ channels, significantly reduced biochanin A-induced relaxation in aortic rings from both groups. However, 4-aminopyridine, a selective inhibitor of voltage-dependent K+ channels, inhibited the relaxation induced by biochanin A in 2K1C rats, whereas no significant differences were observed in sham rats. CONCLUSION: These results suggest that the enhanced relaxation caused by biochanin A in aortic rings from hypertensive rats is endothelium dependent. Vascular smooth muscle K+ channels may be involved in biochanin A-induced relaxation in aortae from hypertensive and normotensive rats. In addition, an endothelium-derived activation of voltage-dependent K+ channels contributes, at least in part, to the relaxant effect of biochanin A in renovascular hypertension.

Clinicopathologic Characteristics of Laterally Spreading Tumors in Colorectum / 대한소화기내시경학회지

BACKGROUND/AIMS: Among colorectal neoplasms, laterally spreading tumors (LSTs) are defined as tumors over 10 mm in diameter that are low in height and grow superficially. We analyzed the clinicopathologic characteristics of LSTs in colorectum. METHODS: Forty six LSTs were analyzed according to their endoscopic and pathologic findings. RESULTS: Incidence of LSTs were 2.0% (46/2,276). Twenty two LSTs (47.8%) were less than 20 mm in diameter, 20 (43.5%) were 20-30 mm, 4 (8.7%) were larger than 30 mm. The most frequent location was rectosigmoid colon (54.3%), followed by ascending colon (21.7%). Morphplogic types were GH types 37.0% (17/46), MN types 30.4% (14/46) and F types 32.6% (15/46). Histologic types were tubular adenomas 65.2% (30/46), tubulovillous adenomas 26.1% (12/46) and villous adenomas 8.7% (4/46). The overall malignancy rate was 19.6% (9/46). Malignancy rates were 4.5% (1/22) in the lesions less than 20 mm, 30.0% (6/20) in 20-30 mm, 50.0% (2/4) in larger than 30 mm. Malignancy rates were 11.8% (2/17) in GH type, 21.4% (3/14) in NM type and 26.7% (4/15) in F type. Carcinoma invaded into the submucosa were present in one lesion of NM types and two of F type. CONCLUSIONS: LSTs larger than 20 mm had high malignant potential, more than 30%. Furthermore, LSTs showed different clinicopathologic characteristics depending on the morphologic classification. NM or F type had higher malignant potential than GH type.

A Case of Hepatocellular Carcinoma with Metastasis to Gingival Mucosa / 대한간학회지

Hepatocellular carcinoma is one of the most common causes of death in Koreans. Most cases of hepatocellular carcinoma are beyond the stage of curative resection at the time of diagnosis due to extrahepatic metastasis as well as wide distribution of tumor in the liver. The lung is the most common site of extrahepatic metastasis but metastasis to gingiva is very rare in hepatocellular carcinoma. We report a case hepatecellular carcinoma with gingival methststasis in a 59 year old male patient.

Long-term effect after Helicobacter pylori eradication in patients with peptic ulcer disease : A retrospective study / 대한내과학회지

BACKGROUND: Eradication therapy for H. pylori infection is known to decrease the recurrence rate of peptic ulcer disease. The aim of this study was to evaluate longterm effect of H. pylori eradication on the recurrence of peptic ulcer disease and the reinfection rate after treatment in Korea. METHODS: Between July 1996 and February 1997, 763 patients who were diagnosed peptic ulcer diseases and H. pylori infection after upper endoscopies in Soonchunhyang university hospital. Among those patients, we reviewed 32 patients who achieved eradication of H. pylori after eradication therapy and could be followed for up to 4 years by (13)C-urea breath test or endoscopy. RESULTS: The mean age of the patients was 51.7 years (range: 29~68). Nine patients had gastric ulcer, 12 had duodenal ulcer and 11 had duodenal and gastric ulcer. An annual reinfection rate of H. pylori was 1.6% in our study. After H. pylori eradication, recurrence of peptic ulcer was detected in three patients (9.4%). CONCLUSION: In our study, the reinfection rate was similar to rates observed in developed countries. H. pylori eradication was effective for preventing recurrent peptic ulcers.

Corelation between the Finding of Magnifying Endoscopy and Histologic Finding in the Helicobactor Pylori Induced Gastritis / 대한소화기내시경학회지

BACKGROUND/AIMS: This is the study to find diagnostic possibility of the H. pylori induced gastritis by using the magnifying endoscope. METHODS: The objectives were 144 pathologies from 48 patients with gastritis. The three sites of gastric mucosa have been magnified up to 80 times by using the magnifying endoscope. According to the patterns of the collecting venule, they have been classified into 3 patterns; regular (R), irregular (I) and disappearance (D) pattern and biopsy of each part has been performed. Each tissue has been evaluated into five kinds of morphological index (point: 0~3) by using an updated Sydney system. RESULTS: In 144 collecting venule, R, I and D-pattern was 19, 67, 58, respectively. Regarding the total score of morphologic points, the point of R-pattern was less than that of D-pattern (p<0.05). Regarding the infection of H. pyrori, the infection rate was 0%, 53.7%, and 60.3% in each pattern, and infection rate of R-pattern was less than other two patterns (p<0.05). Regarding the activity of neutrophile, R-pattern was less than those of I and D-pattern (p<0.05). CONCLUSIONS: Observance of the collecting venule of the gastric mucosa by magnifying endoscopy is considered to be useful when estimating the inflammation degree and H. pylori infection.

A Case of Atypical Fundic Gland Hyperplasia Confirmed by Endoscopic Mucosal Resection / 대한소화기내시경학회지

Fundic gland hyperplasia is a hyperplasia of glandular portion on epithelium of gastric fundus or body. The incidence of fundic gland hyperplasia is 1.4% in the general population. Fundic gland hyperplasia is the most common cause of multiple polyposis. Probably the most cause of fundic gland hyperplasia is a hamartomatous origin but some hyperplastic origin because of spontaneous remission. We have experienced and reported a case of atypical fundic gland hyperplasia confirmed by endoscopic mucosal resection.

A Case of Rumination Syndrome with Simultaneous Repeatetive Contractions in Ambulatory 24 hour Antroduodenal Manometry / 대한소화관운동학회지

Rumination syndrome is defined as a regurgitation of recently ingested food into the mouth with subsequent remastication and reswallowing or spitting out, and absence of structural disease. This is infrequent in adults of normal mental capacity. The true prevalence of rumination syndrome is unknown because few people have medical attention and most of physicians do not recognize this syndrome as a disease. Upper gastrointestinal manometry has been reported to show a characteristic pattern that confirms the diagnosis, namely, the occurrence of synchronous pressure spikes termed "R waves" at all levels in the stomach and small intestine. We assessed a 49-year-old male patient who complained of frequent effortless regurgitation of food. Ambulatory short-segment antroduodenal manometry with pH-metry showed simultaneous repeatetive contractions in all segments associated with regurgitation.

Metallic EndoCoilTM Stent Application for Patients with Malignant Obstructive Jaundice / 대한소화기내시경학회지

We report our experience in five patients with malignant obstructive jaundice with a new self expandable metallic stent, a coil spring made from nickel-titanium alloy. Endoscopic biliary drainage(EBD) is a safe and effective noninvasive biliary drainage method and is indicated with malignant obstructive jaundice. In order to avoid being limited by the size of the instrumentation channel of the endoscope, expandable stents have been developed. The main problems with these expandable metal stents are tumor ingrowth leading to reobstruction, migration of the stent from its original position, and epithelial trauma by the distal hard edges of the stent. The new super-elastic metallic coil stent which has a very strong radial force (EndoCoil'" stent, Instent Co.) was developed to solve the above mentioned problems. The stent which is constricted over an introducing catheter is inserted by transduodenal approach. It expands spontaneously after release to its original 8 mm diameter. During the last 6.5 rnonths, 5 stents were inserted in patients with cholangiocarcinoma, pancreatic carcinoma and cancer of the ampulla of Vater to releave jaundice. Clinical improvement was achieved in all the patients except in one who died from multiple organ metastasis. After a mean follow-up of 6 month., patients had no evidence of biliary reobstruction. Although follow-up is short, these results are encouraging, and this new metallic stent seems to have several advantages over the current commercially available ones.

Colonoscopic Diagnosis of Whipworm Infection / 대한소화기내시경학회지

Trichuriasis is an intestinal infection of human beings caused by Trichuris trichiura, more commonly known as whipworm because of its whip-like appearance. It is characterized by the invasion of the colonic mucosa by the adult trichuris. It is prevalent throughout the world, especially in tropical areas. Diagnosis is made typically by the identification of characteristic barrel-shaped eggs in the feces, although adult worms may be seen rarely at sigmoidoscopy or colonoscopy. We report five cases of whipworm infection that was diagnosed on colonoscopic examination.