Evidence for dual modulation of pepsinogen secretion using isoproterenol, carbachol, CCK-8, forskolin, 8 bromo-cAMP, and A23187 probes

The cellular mechanisms by which pepsinogen (PNG) secretion is controlled are not understood. The aim of this study was to explore whether modulation of PNG secretion is mediated by cAMP or calcium-calmodulin (C-C). PNG secretion in isolated rabbit gastric fundic glands (IGG) was tested, using agents believed to act via cAMP or C-C. IGG were stimulated for 30 minutes with histamine (H) 10(-5) M, isoproterenol (I) 10(-5) M, carbachol (C) 10(-5) M, cholecystokinin-octapeptide (CCK-8) 10(-7) M, forskolin (F) 10(-5) M, 8 bromo-cAMP (8B) 10(-3) M, and A23187 (A) 10(-6) M. PNG levels were determined by spectrophotometric assay of hemoglobin digestion products. PNG amounts secreted were (mean per cent above basal levels of total IGG PNG units +/- SEM): H, -0.02 +/- 0.30%; I, 3.5 +/- 0.9%; C, 5.1 +/- 2.2%; CCK-8, 5.3 +/- 1.5%; F, 10.6 +/- 3.8%; 8B, 13.8 +/- 4.5%; A, 2.1 +/- 1.1%. All secretagogues except H stimulated PNG release significantly above basal levels (p less than 0.05). A primary histaminergic mechanism for pepsinogen secretion is unlikely. Since two other adenylate cyclase activators, isoproterenol and forskolin and the 3':5'-cyclic adenosine monophosphate analog 8-bromo cAMP stimulated pepsinogen secretion, cAMP-dependence is probable. Since carbachol, CCK-8, and A23187, which are believed to act via calcium-calmodulin, also stimulated pepsinogen secretion, this system, too, presumably plays a substantial role. Thus the data support a dual 3':5'-cyclic adenosine monophosphate/calcium-calmodulin modulation of pepsinogen secretion.     

Use of modified nucleotides and uracil-DNA glycosylase (UNG) for the control of contamination in the PCR-based amplification of RNA.

The inadvertent carryover of amplified fragments of nucleic acids (amplicons) is a potential source of contamination in the polymerase chain reaction. Recently, a method has been developed to generate amplicons with deoxyuracil triphosphate (dUTP) and to specifically hydrolyze these amplicons with uracil-DNA glycosylase (UNG) following the completion of the assay. We evaluated this system for the specific amplification of RNA from coxsackievirus A3 and B3. We found that RNA from both viruses could be amplified with dUTP, although the use of this triphosphate in place of TTP resulted in some loss of assay sensitivity. We also found that the dUTP-containing amplicons could be efficiently hydrolyzed by UNG, resulting in a 10,000,000-fold reduction in amplicon concentration with little effect on the native nucleic acid. The dUTP-UNG method has a great deal of potential for reducing amplicon contamination during the routine performance of nucleic acid amplification reactions.     

A randomized controlled trial of electromagnetic therapy in the primary care management of venous leg ulceration

OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care.     

Evaluation of the occult blood test in screening for colorectal neoplasms. A prospective study using flexible endoscopy

Survival rates from colorectal cancer will rise only when polyps and cancers are found at an earlier, curable stage. Consequently, the purpose of the present study was to compare the yield of colonic neoplasms from flexible sigmoidoscopy and colonoscopy with that from occult blood testing. Results from 474 flexible sigmoidoscopies and 1,115 colonoscopies were prospectively recorded during a four-year study period. Colorectal polyps were found in 111 (23.4%) patients undergoing flexible sigmoidoscopy and 325 (29.1%) patients undergoing colonoscopy. Among the 436 patients with polyps, the occult blood test was negative in 282 (64.7%). Among the 51 patients with colorectal cancers, the occult blood test was negative in 20 (39.1%). Thus, testing for occult blood missed the majority of polyps and a large percentage of the carcinomas. These data indicate that lower gastrointestinal endoscopy is superior to occult blood testing as a screening test for detecting colorectal polyps or cancers. Furthermore, given the high incidence of neoplasia in this patient population, the authors suggest that colonoscopy become the screening test of choice for colorectal cancer.