Determination of tryptamine in rat brain by gas chromatography-mass spectrometry

Tryptamine (TA) occurs in trace levels in the brain, but its role in the central nervous system is not clear. However, there is evidence that TA may be a neuromodulator since it binds to specific binding sites in the brain. TA was measured as a diheptafluorobutyryl derivative in rat whole brain by capillary gas chromatography—mass spectrometry using negative chemical ionization (NCI) and single ion monitoring (SIM). d₄-TA was used as the internal standard. The ions m/z 532 and m/z 536 were monitored to identify TA and d₄-TA, respectively and to calculate the concentration of TA in rat whole brain which was found to be 0.19 ± 0.08 ng g⁻¹ (n = 8). The results confirm the earlier TA concentrations measured by GC—MS using positive electron impact ionization. However, NCI improved the signal/noise ratio of the method increasing its sensitivity for TA.     

T-antigen expression by peanut agglutinin staining relates to mucosal dysplasia in ulcerative colitis

Staining of 326 rectal mucosal biopsies from ulcerative colitis patients with peanut agglutinin (PNA), which binds to the T-blood group antigen and has been claimed to reflect a cancer-associated mucin alteration, showed highly significant direct associations with mucosal dysplasia (P less than 0.001), disease activity (P less than 0.001), and subsequent development of rectal cancer in a smaller series of patients (P = 0.005). Staining for normal colonic mucin by the Dolichos biflorus (DBA) lectin related significantly and inversely to dysplasia. Intense normal colon mucin staining by DBA related significantly (P less than 0.025) to long disease duration and to subsequent development of cancer (P = 0.02). The latter association is based on a small number of patients only and is not considered conclusive evidence, but may provide a link with goblet-cell hyperplasia. The authors conclude that although T-antigen expression relates to dysplasia, the findings of "false" positive and negative rates of 22 and 33 percent respectively, make it unlikely that staining of biopsy sections for the T-antigen by peanut agglutinin will contribute materially to routine assessment for dysplasia and cancer risk prediction in patients with ulcerative colitis.     

Improved Corneal Pilocarpine Permeability with O,O′-(l,4-Xylylene) Bispilocarpic Acid Ester Double Prodrugs

0,0-(l,4-Xylylene) bispilocarpic acid esters are pilocarpine pro-drugs containing two pilocarpic acid monoesters linked with one pro-moiety. Each mole of prodrug forms two pilocarpine moles in the presence of esterases. Corneal uptake and permeability of various bispilocarpic acid diesters were investigated in vitro using isolated albino rabbit corneas. The permeability coefficient of pilocarpine was 2.8 × 10 ^–6 cm/sec, whereas for bispilocarpic acid diesters, despite their large molecular weights (between 638 and 722), permeability coefficients were 6.5–20.2 × 10 ^–6 cm/sec. Only pilocarpine, and no intact prodrug, was observed at the endothelial side. Corneal uptake was increased with increasing lipophilicity, but a parabolic relationship between the logarithm of the apparent partition coefficient (1-octanol–pH 7.4 phosphate buffer) (log PC) and the corneal permeability was noticed. Corneal permeability and the rate of enzymatic hydrolysis of the compounds correlated well. The corneal permeability of pilocarpine given as lipophilic bispilocarpic acid diester (log PC 3) prodrugs seems to be controlled by the formation of pilocarpine in the corneal epithelium rather than by the absorption of prodrugs into the epithelium or their epithelium–stroma transport rate.     

Helicobacter pylori-associated diseases

Since the initial report 20 years ago by Marshall and Warren of an unidentified curved bacillus located on the gastric epithelium of patients with chronic active gastritis, the discovery of Helicobacter pylori and its association with a number of gastrointestinal diseases has revolutionized the field of gastroenterology. Although the association of H. pylori infection with peptic ulcer disease, chronic gastritis, mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma has been well documented over the past two decades, other areas remain less clear, including the role of H. pylori in gastropathy associated with nonsteroidal anti-inflammatory drugs, gastroesophageal reflux disease, and both uninvestigated and nonulcer dyspepsia. Although these areas still remain somewhat controversial, recent reports further clarify the role of H. pylori in these conditions. A review of the recent literature regarding H. pylori-associated diseases is presented along with recommendations for diagnosis and treatment of H. pylori infection.     

An assessment of the management of acute bleeding varices: a multicenter prospective member-based study

OBJECTIVE: Bleeding from esophagogastric varices is a major complication of portal hypertension. Despite recent practice guidelines for the management of bleeding esophageal or gastric varices, the widespread application of these measures by gastroenterologists has not been evaluated. The purpose of this study was to continue the concept of membership-based research within diverse practice settings by expanding the American College of Gastroenterology (ACG) GI Bleeding Registry to assess the management and outcome of acute variceal bleeding. METHODS: All ACG members (domestic and foreign) were invited to participate during the 1997 Annual Fall meeting and by mail. Data were collected over 12 months. Information obtained included physician training, practice demographics, patient demographics, disease etiology and severity, clinical presentation, medications, transfusion needs, therapy, complications, and rebleeding within 2 wk. RESULTS: A total of 93 physicians/centers (79.6% domestic, 26.9% university and affiliated, 3.2% Veterans Affairs) participated. Complete demographic data were available for 725 of the 741 patients enrolled with index bleeding. The median age of these 725 patients was 52 yr and 73.3% were male. The most common single etiology for portal hypertension was cirrhosis (94.3%). The most common causes of cirrhosis were alcohol (56.7%), hepatitis C virus (30.3%), and hepatitis B virus (10.0%). Hemodynamic instability was noted in 60.7% of the patients (22.3% tachycardic, 9.7% orthostatic, 28.7% hypotensive). Index interventions included banding (40.8%; median five bands), sclerotherapy (36.3%), combination banding/sclerotherapy (6.2%), octreotide (52.6%; median 3 days), balloon tamponade (5.5%), transjugular intrahepatic portosystemic shunt (TIPS) (6.6%), liver transplantation (1.1%), surgical shunt (0.7%), and embolization (0.1%). Transfusion of packed red blood cells, fresh frozen plasma, and platelets was given in 83.4%, 44.7%, and 24.6% of the patients with index bleeding, respectively. Median transfusion was four units of packed red blood cells, three units of fresh frozen plasma, and 1.5 units of platelets. Rebleeding occurred in 92 of the 741 patients (12.6%) at a median of 7 days (mean 11 days) and was treated by banding (18.5%; median six bands), sclerotherapy (30.4%), octreotide (63%; median 2 days), balloon tamponade (17.4%), TIPS (15.2%), and surgical shunt (3.3%). Complications from the index bleeding and rebleeding within 2 wk included ulceration (2.6%, 2.2%), aspiration (2.4%, 3.3%), medication side effects (0.8%, 0%), dysphagia (2.3%, 0%), odynophagia (2.2%,0%), encephalopathy (13%,17.4%), and hepatorenal syndrome (2.4%, 2.2%), respectively. After the index bleeding, 46.2% of patients were treated with beta-blockers and 8.2% with nitrates. The majority of patients with index bleeding had Child's B cirrhosis (61.5%). Patients presenting with recurrent bleeding had mostly Child's B (46.7%) or Child's C cirrhosis (44.6%). The overall short-term mortality after index bleeding was 12.9%. CONCLUSIONS: Acute variceal hemorrhage occurs more often in patients with Child's B and C cirrhosis. Endoscopic banding is the most common single endoscopic intervention. Adjunctive pharmacotherapy is prevalent acutely and after stabilization. Both morbidity and mortality may be lower than reported in previous studies.     

Palliative dilation of esophageal carcinoma

The authors' experience with palliative dilation of 46 consecutive patients evaluated for squamous cell carcinoma of the esophagus was retrospectively reviewed. Thirty-nine of 46 patients (85%) underwent dilation in order to palliate symptoms, enable endoscopy and biopsy, or prepare for placement of an esophageal prosthesis. Thirty-two of the 46 patients (70%) were treated with radiation therapy and seven (15%) underwent placement of an esophageal prosthesis. Thirty-five of the 39 patients dilated (90%) noted improvement in swallowing, allowing resumption of a soft or regular diet. Complications were noted in three of the 39 patients dilated (8%). The authors conclude that peroral dilation is a safe, effective, and probably underutilized method of palliation in patients with squamous cell esophageal carcinoma.     

Gastroduodenal Mucus Gel Thickness in Patients with Helicobacter pylori: A Method for Assessment of Biopsy Specimens

The gastroduodenal mucus layer is considered the primary mucosal protective barrier, especially important in the maintenance of a mucosal pH gradient. Thus, the measurement of the mucus layer thickness in various disease states could advance our understanding of gastroduodenal pathophysiology. We present a novel method for measuring the mucus layer in endoscopic biopsy material and compare layer thickness in Helicobacter pylori (HP)-negative and HP-positive specimens. Endoscopic biopsies were obtained from 17 patients with gastroduodenal mucosa harboring HP and from 15 patients without current HP colonization. The thickness of the mucus layer was measured in fresh specimens by the phase-contrast dark-field microscopy technique. In patients with confirmed HP infection, the thickness of the mucus layer (mean +/- SD) was 0.093 +/- 0.033 mm in duodenal, 0.085 +/- 0.027 mm in antral, and 0.105 +/- 0.033 mm in corporal mucosa. In patients without concomitant HP colonization, the thickness of the mucus gel was 0.162 +/- 0.045 mm, 0.175 +/- 0.067 mm, and 0.161 +/- 0.064 mm in duodenum, antrum, and corpus, respectively. The differences between the means were statistically significant (p less than 0.001 for the duodenal, p less than 0.001 for antral, and p less than 0.01 for corporal mucosa). This study suggests that colonization of the gastroduodenal mucosa by HP impairs the mucus layer covering the surface epithelium. This mucus layer impairment may lead to mucosal injury with subsequent development of inflammation and, possibly, peptic ulcer disease.     

Helicobacter pylori-related disease: guidelines for testing and treatment

OBJECTIVE: To develop practical guidelines for the treatment of patients with suspected and documented Helicobacter pylori-related gastroduodenal diseases. METHODS: A panel of physicians with expertise in H. pylori reviewed, critically appraised, and synthesized the literature on assigned topics and presented their overviews to the panel. Consensus was obtained in controversial areas through discussion. RESULTS AND CONCLUSIONS: The panel recommended testing for H. pylori in patients with active ulcers, a history of ulcers, or gastric mucosa-associated lymphoid tissue lymphomas. Young, otherwise healthy patients with ulcerlike dyspepsia and those with a family history or fear of gastric cancer may also undergo H pylori testing. Non-endoscopic methods are preferred for H. pylori diagnosis. Dual medication regimens should not be used for therapy; twice-daily triple therapy with a proton pump inhibitor or ranitidine bismuth citrate, clarithromycin, and amoxicillin for 10 to 14 days is an appropriate therapy. Posttreatment assessment of H. pylori status using urea breath testing should be considered in patients with a documented history of ulcer disease or with persistent symptoms.     

Highly efficient and reliable chemically assisted enucleation method for handmade cloning in cattle

The purpose of the present study was to find an efficient and reliable chemically assisted procedure for enucleation related to the handmade cloning (HMC) technique. After in vitro maturation oocytes were incubated in 0.5 microg mL(-1) demecolcine for 2 h. Subsequently, zonae pellucidae were digested with pronase, and one-third of the cytoplasm connected to an extrusion cone was removed by hand using a microblade. The remaining two-thirds were used as recipients for HMC, and reconstructed and activated embryos were cultured for 7 days. The time-dependent manner of the development of extrusion cones, the efficiency (oriented bisection per oocyte; 94%), reliability (success per attempted enucleation; 98%), and the blastocyst per reconstructed embryo rates (48%) were measured. Ultrastructural analyses demonstrated that demecolcine treatment resulted in disoriented and haphazardly orientated microtubules. The general ultrastructure of the oocyte organelles, however, appeared to be unaltered by the treatments. Considering that no oocyte selection based on polar body presence was performed, this system seems to be more efficient and reliable than any other enucleation method. Moreover, expensive equipment (inverted fluorescence microscope) and a potentially harmful step (staining and ultraviolet illumination) can be eliminated from the HMC procedure without compromising the high in vitro efficiency.