Hiroaki Okabe

Pretreatment staging of endoscopically early gastric cancer with a 15 MHz ultrasound catheter probe

BACKGROUND The usefulness of and problems associated with an ultrasound catheter probe in the pretreatment staging of endoscopically early gastric cancer remain unexplored. METHODS Endoscopic ultrasonography using a 15 MHz catheter probe of 2.6 mm diameter was performed in a prospective study to determine the pretherapy staging of endoscopically early gastric cancer in 78 patients. The results of the ultrasound images were compared with the histologic findings of the specimens obtained by endoscopic mucosal resection or surgical resection. RESULTS The accuracy of the catheter probe for depth of invasion of endoscopically early gastric cancers was 67% (52 of 78 patients). The accuracy in determining depth of invasion in relation to endoscopic type was significantly higher for the elevated type (91%) than for the depressed type of early cancer (56%) (p < 0.01). The staging accuracy classified by histologic type was significantly higher for differentiated (86%) than for undifferentiated (18%) cancer (p < 0.01). Staging accuracy decreased as tumor size increased. The accuracy, sensitivity, and specificity for nodal staging were 80%, 17%, and 90%, respectively. CONCLUSIONS A 15 MHz ultrasound catheter probe is most useful for determining depth of invasion when the tumor is histologically differentiated and endoscopically of the small elevated type early gastric cancer, but it is unreliable in the diagnosis of metastatic lymph nodes.

A case of acute phlegmonous gastritis successfully treated with antibiotics.

Acute phlegmonous gastritis is a rare disorder in which bacterial infection occurs in the gastric wall. Gastrectomy involving the affected area has been thought to be an effective form of treatment. The authors report a case of a 32-year-old woman who had severe upper abdominal pain without signs of peritoneal irritation. Endoscopy showed edematous and reddened gastric mucosa with a mass lesion in the gastric antrum. Endoscopic ultrasonography showed thickening of the antral wall and a low-echoic mass in the gastric antrum, thought to represent a fluid collection. White pus was aspirated from the mass. Localized type of acute phlegmonous gastritis with a gastric abscess was diagnosed. Culture of the pus showed Streptococcus pneumoniae. Through early diagnosis without laparotomy, the patients gastritis was successfully treated with antibiotics alone.

Interaction between atrial natriuretic peptide and vasoactive intestinal peptide in guinea pig cecal smooth muscle

BACKGROUNDS & AIMS The role of atrial natriuretic peptide (ANP) in gastrointestinal motility is still unclear. The aim of this study was to investigate the relationship between ANP and vasoactive intestinal peptide (VIP) in guinea pig cecal circular smooth muscle cells. METHODS The inhibition of 125I-ANP binding or 125I-VIP binding to cecal smooth muscle cells was assessed using unlabeled peptides (i.e., ANP, ANP fragments, VIP, secretin, and peptide histidine isoleucine); the effect of ANP, ANP fragments, and VIP on muscle contraction stimulated by 1 mumol/L carbachol was assessed; and the inhibitory effects of ANP 1-11 on VIP-induced relaxation, ANP 1-11 and VIP 10-28 (a VIP antagonist) on ANP-induced relaxation, and nitric oxide production inhibitors on ANP-induced relaxation were assessed. RESULTS The specific binding of 125I-ANP was inhibited completely by unlabeled ANP and VIP in a dose-dependent manner but only slightly inhibited by secretin and peptide histidine isoleucine. ANP 1-11 and C-atrial natriuretic factor inhibited the binding of 125I-ANP with a lower affinity than ANP. ANP only partly inhibited 125I-VIP binding. ANP and VIP inhibited 1 mumol/L carbachol-induced contraction in a dose-dependent manner. ANP 1-11 significantly inhibited VIP-induced relaxation. ANP 1-11, VIP 10-28, and NO production inhibitors completely inhibited ANP-induced relaxation. CONCLUSIONS The results of the study showed that ANP 1-11 antagonized ANP-induced relaxation and that ANP stimulated NO production and subsequently induced relaxation via a receptor to which VIP binds.

Two Endothelin Receptors (ETA and ETB) Expressed on Circular Smooth Muscle Cells of Guinea Pig Cecum

BACKGROUND/AIMS The functional receptors for endothelin (ET) in colonic smooth muscle are still unknown. This study investigated the expression of ET receptors in isolated circular smooth muscle cells of guinea pig cecum. METHODS Inhibition of 125I-ET-1 binding was examined using unlabeled ET-1, ET-2, ET-3, sarafotoxin 6c (S6c), and ETA antagonists. Expression of the ET-receptor message was investigated using reverse-transcription polymerase chain reaction. The contractile potency of the ET family and the inhibitory effect of ETA antagonists on ET-1-induced contraction were also investigated. RESULTS Unlabeled ET-1, ET-2, and ET-3 inhibited the specific binding of 125I-ET-1 in a concentration-dependent manner, but the inhibitory effect of ET-3 was smaller than those of ET-1 and ET-2. At a 10(-6) mol/L concentration of S6c, the specific binding of 125I-ET-1 was 24.7%. S6c had clearly reached maximal inhibition. Abundant polymerase chain reaction products for both the ETA and the ETB message were observed. ET-1 and ET-2 showed similar contractile potency, but ET-3-induced and S6c-induced contractions were significantly less potent than the ET-1-induced contraction. A significant response to S6c was obtained at a concentration as low as 10(-10) mol/L. The ETA antagonists BQ-123 and FR 139317 significantly inhibited ET-1-induced contraction. CONCLUSIONS The results show a direct contractile effect of ETs on circular smooth muscle of guinea pig cecum and the presence of both ETA- and ETB-receptor subtypes.

Direct contractile effect of endothelin-1 on isolated circular smooth muscle cells of guinea pig caecum

Smooth muscle cells isolated from the circular muscle layers of the guinea pig caecum were used to determine whether endothelin-1 (ET-1) can cause contraction by exerting a direct action on smooth muscle cells. In addition, the inhibitory effects of 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8), an inhibitor of intracellular Ca2+ release, verapamil, a Ca2+ channel blocker, and removal of extracellular Ca2+ on the ET-1-induced muscle contraction were examined. ET-1 elicited a contractile response of isolated smooth muscle cells in a dose-dependent manner (ED50: 2 nM). TMB-8, verapamil, and removal of extracellular Ca2+ significantly inhibited the contraction produced by ET-1. These results strongly suggest that ET-1 has a direct contractile effect on circular smooth muscle cells of the guinea pig caecum, and that this contraction depends on both intracellular and extracellular Ca2+.

Desensitization for sulfasalazine-induced skin rash in a patient with ulcerative colitis

A patient with ulcerative colitis developed a sulfasalazine-induced skin allergy manifested by a urticaria rash. The patient underwent drug desensitization. The first desensitization, done according to Holdsworths protocol, resulted in eruption with itching at a dose of 800 mg. The second desensitization, with Dass protocol, failed to reintroduce the drug because of urticarial eruptions. The third challenge, with a more gradual increase in sulfasalazine dose than that use in Holdsworths protocol, successfully desensitized the patient. The relationship between the drug and various adverse reactions is reviewed and the desensitization to sulfasalazine is discussed.

Functional EndothelinA Receptor on Gastric Smooth Muscle Cells

Smooth muscle cells isolated from the gastric muscle layers of the guinea pig were used to examine the functional endothelin receptor subtype responsible for gastric smooth muscle contraction by endot