Endoscopic submucosal dissection of early colorectal tumors using a grasping-type scissors forceps: a preliminary clinical study.

To reduce the risk of complications related to endoscopic submucosal dissection (ESD), we developed a new grasping-type scissors forceps (GSF), which can grasp and incise the targeted tissue using an electrosurgical current. We prospectively evaluated the efficacy and safety of ESD using GSF for the removal of colorectal tumors in 10 consecutive patients. After the submucosa had been injected with a solution, the lesion was separated from the surrounding normal mucosa by complete incision around the lesion using the GSF. A piece of submucosal tissue was grasped and cut with the GSF using an electrosurgical current to achieve submucosal excision. All lesions were treated easily and safely with no unexpected incisions. No delayed hemorrhage or perforation occurred. En bloc resection was obtained in all cases. The tumor-free lateral/basal margins were obtained in eight out of 10 patients. ESD using GSF appears to be an easy, safe, and technically efficient method for resecting early colorectal tumors.

Clinical and endoscopic characteristics of acute haemorrhagic rectal ulcer, and endoscopic haemostatic treatment: a retrospective study of 95 patients.

AIM: Acute haemorrhagic rectal ulcer (AHRU) is characterized by sudden onset of painless and massive rectal bleeding in elderly bedridden patients who have serious illness. Endoscopic diagnosis and management of AHRU is, however, still controversial. We retrospectively investigated 95 AHRU patients to elucidate the clinical characteristics, endoscopic findings and haemostatic strategies. METHOD: Between January 1999 and March 2007, 95 patients were diagnosed with AHRU in our hospital. Medical records and colonoscopy files were reviewed. Clinical features, colonoscopic findings, haemostatic treatment and outcome of the patients were evaluated. RESULTS: Eighty per cent of the patients were bedridden at the onset. The most frequent underlying disorder was cerebrovascular disease (36.8%). Hypoalbuminaemia (< 3.5 g/dl) was seen in 92.6% of the patients. Endoscopic findings of AHRU were classified as circumferential ulcer (41.1%), linear or nearly round small ulcer(s) (44.2%), circumferential and small ulcer(s) (7.4%) and Dieulafoy-like ulcer (7.4%). Primary endoscopic haemostatic treatment was performed in 45.3% of cases. Recurrent bleeding occurred in 24.2% of patients. Permanent haemostasis was achieved by secondary endoscopic treatment in 82.6% of re-bleeding patients. CONCLUSION: Understanding the typical clinical and endoscopic findings and careful endoscopic examination are important for the accurate diagnosis of AHRU, and endoscopic haemostatic therapy may be effective for bleeding patients.

Endoscopic band ligation therapy for upper gastrointestinal bleeding related to Mallory-Weiss syndrome.

BACKGROUND: No consensus exists as to the best endoscopic treatment for Mallory-Weiss syndrome. Endoscopic band ligation is a readily available and easily learned technique. This prospective study evaluated the efficacy and safety of endoscopic band ligation therapy for Mallory-Weiss syndrome. METHODS: From August 1998 to June 2005, a clinical trial assessed 37 patients with a diagnosis of Mallory-Weiss syndrome who had active bleeding, exposed vessels, or both. Their lesions were treated using endoscopic band ligation. RESULTS: Endoscopic band ligation was successful in 36 of 37 cases, with a follow-up period ranging from 1 to 24 months. The remaining patient had severe liver failure and disseminated intravascular coagulation. The patient bled again at 12 h and subsequently died. Except for this case, no recurrent bleeding, perforation, or other complications occurred. CONCLUSIONS: The study results suggest that endoscopic band ligation is an effective, safe, and easily learned procedure for treating upper gastrointestinal bleeding related to Mallory-Weiss syndrome.

EUS-guided endoscopic resection using band ligation of oesophageal granular cell tumour: report of a case.

A 60-year-old Japanese man was referred for treatment of a polypoid oesophageal tumour. Radiographic examination of the upper gastrointestinal tract disclosed a nodule with central depression in the lower esophagus. By endoscopy the nodule was yellowish and appeared submucosal. Endoscopic ultrasonography demonstrated a hypoechoic solid tumour limited in submucosa without lymph node involvement. Endoscopic resection using band ligation was performed under guidance by endoscopic ultrasonography. By histologic examination the tumour consisted of large cells arranged in nests. These cells had abundant granular cytoplasm and small round nuclei. They expressed S-100 protein and were CD68, and periodic acid-Schiff positive. No expression of alpha-smooth muscle actin was noted. The tumour was limited in submucosa. Findings were consistent with complete endoscopic resection. This report may be the first concerning an oesophageal granular cell tumour successfully treated with EUS-guided endoscopic resection using band ligation.

Colonic muco-submucosal elongated polyp: diagnosis with endoscopic ultrasound.

Colonic muco-submucosal elongated polyp is a new clinical entity first reported in 1998. The purpose of this report is to determine the value of endoscopic ultrasound in the diagnosis of this condition. We reviewed the endosonographic and histological findings of seven colonic muco-submucosal elongated polyps that were removed completely by endoscopic resection or surgery. The lesions appeared as pedunculated submucosal tumours, measuring 1-4 cm in maximal diameter. Endosonographically, all lesions consisted of mucosal and submucosal layers, and microcystic components were found in the submucosal layer. There were no echogenic masses or muscularis propria within the polyps. These endosonographic features corresponded to histological findings of this type of polyp which was covered with normal mucosa and composed of submucosal layer alone. The submucosal layer consisted of oedematous, loose, connective tissue and/or fibrous tissue, accompanied by dilated blood vessels and lymphatics. Endoscopic ultrasound enabled differentiation of colonic muco-submucosal elongated polyp from other submucosal lesions.

Intracellular Mg2+ influences both open and closed times of a native Ca2+-activated BK channel in cultured human renal proximal tubule cells.

Effects of intracellular Mg2+ on a native Ca(2+)-and voltage-sensitive large-conductance K+ channel in cultured human renal proximal tubule cells were examined with the patch-clamp technique in the inside-out mode. At an intracellular concentration of Ca2+ ([Ca2+](i)) of 10(-5)-10(-4) M, addition of 1-10 mM: Mg2+ increased the open probability (P(o)) of the channel, which shifted the P(o) -membrane potential (V(m)) relationship to the negative voltage direction without causing an appreciable change in the gating charge (Boltzmann constant). However, the Mg(2+)-induced increase in P(o) was suppressed at a relatively low [Ca2+](i) (10(-5.5)-10(-6) M). Dwell-time histograms have revealed that addition of Mg2+ mainly increased P(o) by extending open times at 10(-5) M Ca2+ and extending both open and closed times simultaneously at 10(-5.5) M Ca2+. Since our data showed that raising the [Ca2+](i) from 10(-5) to 10(-4) M increased P(o) mainly by shortening the closed time, extension of the closed time at 10(-5.5) M Ca(2+) would result from the Mg(2+)-inhibited Ca(2+)-dependent activation. At a constant V(m), adding Mg2+ enhanced the sigmoidicity of the P(o)-[Ca2+](i) relationship with an increase in the Hill coefficient. These results suggest that the major action of Mg2+ on this channel is to elevate P(o) by lengthening the open time, while extension of the closed time at a relatively low [Ca2+](i) results from a lowering of the sensitivity to Ca2+ of the channel by Mg2+, which causes the increase in the Hill coefficient.

p53 and PTEN/MMAC1 mutational analysis of the small-intestinal cancer.

A 66-year-old female, suffering from small-intestinal cancer underwent resection of the small intestine. Genome DNAs were extracted from the patient's blood and small-intestinal cancer and were subjected to a polymerase chain reaction-single strand conformation polymorphism and nucleotide sequence analysis for exons of the p53 and PTEN/MMAC1 genes to search for any mutations. The sequence analysis revealed a point mutation of the p53 codon 93 in the cancer DNA; however, no mutation of the PTEN/MMAC1 gene was observed in either the blood or cancer DNA. The p53 mutation, therefore, seems to be related to tumour progression of small-intestinal cancer; however, no relationship was found between the PTEN/MMAC1 gene and the small-intestinal cancer.

Properties of a Ca(2+)-activated large conductance K(+) channel with ATP sensitivity in human renal proximal tubule cells.

The properties of a native Ca(2+)-activated large conductance K(+) channel (BK channel) present in the surface membrane of cultured human renal proximal tubule epithelial cells (RPTECs) were investigated by using the patch-clamp technique. The slope conductance of the BK channel was about 295 pS, and the channel was selective to K(+) over Na(+), with a selectivity ratio of about 12.2. The activity of the channel was almost maximally enhanced by 10(-4 )M or more Ca(2+) in the cytoplasmic surface of the patch membrane and was markedly diminished by reducing the cytoplasmic Ca(2+) to 10(-6) M at the membrane potential of about 0 mV. The depolarization of the patch membrane also enhanced the channel activity, and hyperpolarization lowered it. K(+) channel blockers, Ba(2+) (0.1-1 mM), tetraethylammonium (1 mM), and charybdotoxin (100 nM), were effective for the suppression of channel activity. A significant feature of the K(+) channel was that channel activity maintained by 10(-5)-10(-4 )M Ca(2+) in inside-out patches was inhibited by the addition of ATP (1-10 mM) to the bath solution. ATPgammaS, and a nonhydrolyzable ATP analogue, 5'-adenylylimidodiphosphate (AMP-PNP), also had inhibitory effects on channel activity. However, an inhibitor of ATP-sensitive K(+) channels, glibenclamide (0.1 mM), induced no appreciable change in channel activity from both intra- and extracellular sides. These results suggest that besides the common natures of the BK channel family such as regulation by cytoplasmic Ca(2+) and membrane potential, the BK channel in RPTECs is directly inhibited by intracellular ATP independent of phosphorylation processes and sulfonylurea receptor.

An ATP-regulated and pH-sensitive inwardly rectifying K(+) channel in cultured human proximal tubule cells.

Although renal K(+) channels along the nephron have been explored in various animal species, little is known about the K(+) channels in human proximal tubule cells. Using the patch-clamp technique, we investigated the properties of an inwardly rectifying K(+) channel present in the surface membrane of cultured human proximal tubule cells of normal kidney origin. This channel was the most frequently observed K(+) channel in cell-attached patches, and cytoplasmic ATP was required to maintain channel activity in inside-out patches. Its single channel conductance was about 42 pS for inward currents and 7 pS for outward currents under the symmetrical K(+) condition. The ATP effect on channel activity was dose-dependently stimulatory within a range of 0.1 to 10 mM, and a nonhydrolyzable ATP analog, AMP-PNP (3 mM), had no effect on channel activity in either the presence or absence of ATP (1 mM). The channel activity observed in cell-attached patches was reduced to 30 to 50% of controls by a membrane-permeable nonspecific protein kinase inhibitor, K252a (1 microM), or a potent protein kinase A inhibitor, KT5720 (500 nM). In contrast, a membrane-permeable cAMP analog, 8Br-cAMP (100 microM), induced a twofold increase in channel activity. The addition of a catalytic subunit of protein kinase A (PKA-CS, 100 U/ml) to the bath in inside-out patches stimulated channel activity in the presence of 1 mM ATP. Furthermore, the channel activity maintained with 1 mM ATP in inside-out patches was suppressed by internal acidification and enhanced by alkalization. These results suggest that the activity of the inwardly rectifying K(+) channel in cultured human proximal tubule cells was ATP-dependent and regulated at least in part by cAMP/PKA-mediated phosphorylation processes and intracellular pH.

Aberrant intracellular localization of RCAS1 is associated with tumor progression of gastric cancer.

A novel tumor-associated antigen, RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is expressed at a high frequency in human uterine and ovarian cancer cells as well as in other mammalian cancer cells. We investigated a relationship between RCAS1 expression and clinicopathological features in gastric cancer. Immunohistochemically, RCAS1 was detected in 98.4% of gastric carcinomas. However, its expression was also observed in non-cancerous gastric epithelial cells including gastric adenomas (100%), gastric ulcers (66.7%) and normal gastric epithelia (100%). Striking difference was observed in the pattern of RCAS1 expression between benign and malignant cells. In cases of normal gastric mucosae, gastric ulcers and gastric adenomas, RCAS1 was localized only in the perinuclear region of the mucosal epithelial cells (PN pattern), while, in most of gastric cancers (83.9%), it was detected diffusely in the cytoplasm and cell membranes of the tumor cells (DC pattern). In semi-quantitative RT-PCR analysis, RCAS1 mRNA levels in gastric adenocarcinoma tissues were significantly higher than those in non-neoplastic tissues (p=0.038). The PN pattern of RCAS1 expression was more frequently observed in well differentiated adenocarcinoma (25%) than in moderately differentiated adenocarcinoma (0%) (p=0.01). In addition, it is noteworthy that DC pattern of RCAS1 expression was more frequently recognized in carcinomas which invaded beyond the submucosa (100%) compared to intramucosal carcinoma (67.7%) (p=0.0026). These findings suggest that altered intracellular distribution of RCAS1 is strictly associated with tumor progression of gastric cancer and is a useful marker for the diagnosis and prognosis in gastric cancer.

Ca(2+)-dependent inhibition of inwardly rectifying K(+) channel in opossum kidney cells.

The effect of intracellular Ca(2+) on the activity of the inwardly rectifying ATP-regulated K(+) channel with an inward conductance of about 90 pS was examined by using the patch-clamp technique in opossum kidney proximal tubule (OKP) cells. The activity of the inwardly rectifying K(+) channel rapidly declined with an application of ionomycin (1 microM) in the presence of 10(-6) M Ca(2+) in cell-attached patches. The application of 10 microM phorbor-12-myristate-acetate (PMA) with 10(-6) M Ca(2+) reduced the K(+) channel activity. Although the channel activity was not influenced by an increase of bath Ca(2+) from 10(-7.5) to 10(-6) M, the activity was inhibited by protein kinase C (PKC, 1 U/ml) with 10(-6) M Ca(2+) in inside-out patches. The inhibitory effect of Ca(2+) with ionomycin on the channel activity was diminished by the pretreatment with a specific PKC inhibitor, GF 109203X (5 microM), in cell-attached patches. By contrast, the application of Ca(2+)/calmodulin kinase II (CaMK II, 300 pM) dramatically increased this channel activity in inside-out patches. In cell-attached patches, the addition of both GF 109203X and cyclospolin A (5 microM), a potent inhibitor of protein phosphatase 2B (calcineurin), instead stimulated the K(+) channel activity with ionomycin and 10(-6) M Ca(2+). The addition of protein phosphatase 2B (calcineurin) (2 U/ml) to the bath with calmodulin (1 microM) and Ni(2+) (10 microM) to stimulate calcineurin inhibited the channel activity in inside-out patches. Furthermore, the inhibitory effect of PKC or calcineurin on this channel activity was abolished by a removal of Ca(2+) from bath solution. These results suggest that Ca(2+)-dependent inhibitory effect on the inwardly rectifying K(+) channel in OKP cells was mainly mediated by Ca(2+)-PKC-mediated phosphorylation, and that the Ca(2+)-calmodulin-dependent phosphorylation process may be counterbalanced by the Ca(2+)-calmodulin-dependent dephosphorylation process.

Quantitation by (1)H-NMR of dolichol, cholesterol and choline-containing lipids in extracts of normal and phathological thyroid tissue.

Proton magnetic resonance spectroscopy at 1.9 T was used to quantify dolichols, cholesterols, choline-containing phospholipids and double bonds in unsaturated acyl chains in lipid extracts of four types of thyroid tissue [normal (n = 27), papillary cancer (n = 15), adenoma (n = 13) and Basedow disease (n = 6)]. In normal thyroid the mean concentrations of dolichol, cholesterol and phospholipids were 1.2, 3.6 and 2.1 micromol/g wet weight, respectively. The concentrations of these lipids exhibited positive mutual correlations and positive correlations with patient age. The increase in dolichol in elderly human thyroid may be due to the accumulation of lysosomes and may help to compensate for the decrease in the activity of lysosomal enzymes and in thyroid hormone production and release. Dolichol concentrations were significantly lower in papillary cancer (0.4 micromol/g) and Basedow disease (0.3 micromol/g) compared to normal thyroid (p < 0.01 and p < 0.05, respectively), while cholesterol was enhanced only in cancer tissue (10.7 micromol/g). Benign adenoma exhibited normal levels of both dolichol and cholesterol. These results suggest that the synthesis and accumulation of isoprenoids are normal in adenoma but not in cancer.