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Biomedical subjects

G W Stevenson

Publications and source records attributed to G W Stevenson.

At least 109 records · Page 6Linked to original sources
PubMed1988

Prospective comparison of double contrast barium enema plus flexible sigmoidoscopy v colonoscopy in rectal bleeding: barium enema v colonoscopy in rectal bleeding.

Rectal bleeding often heralds serious colonic disease. The literature suggests that colonoscopy is superior to barium enema plus sigmoidoscopy, although no good comparative studies exist. Seventy one patients with overt rectal bleeding had prospectively flexible sigmoidoscopy, double contrast barium enema and colonoscopy completed independently. Against the gold standard, the sensitivity and specificity of colonoscopy were 0.69 and 0.78 respectively for a spectrum of colonic lesions, while for combined flexible sigmoidoscopy and double contrast barium enema these values were 0.80 and 0.56, respectively. When assessing adenoma or carcinoma, colonoscopy was more sensitive at 0.82 v 0.73, while flexible sigmoidoscopy plus double contrast barium enema was superior for detecting diverticular disease. The positive predictive value for colonoscopy was 0.87 against 0.81 for flexible sigmoidoscopy and double contrast barium enema. This study confirms that colonoscopy should be a first line investigation in subjects likely to require biopsy or therapeutic intervention.

Barium Sulfate↗
PubMed1988

Defecography commode.

A mobile wooden commode was designed and built for use in defecography. The commode is made of 1/2-inch-thick plywood with birch veneer and a solid clear pine seat. Water or copper sheets are recommended for radiation filtration. A radiopaque ruler attached to the commode with a spring enables midline measurements. The modifications suggested by the authors have helped with setup and have improved the images acquired.

Humans↗
PubMed1988

Cow's milk protein/soy protein allergy: gastrointestinal imaging.

Positive radiologic findings were identified in the small and large bowels in three infants with various gastrointestinal manifestations of cow's milk protein/soy protein allergy, which was diagnosed on the basis of clinical features and histologic findings. Small bowel findings were thickened valvulae conniventes (plicae circulares), a ribbon-like ileum, and a thickened bowel wall. Narrowing, thumbprinting, and spasm were seen in the large bowel. These cases were seen at intervals far enough apart to exclude an endemic infection. The diagnosis of food protein allergy should be considered when diffuse small bowel disease or colitis is identified in an infant.

Dietary Proteins↗
PubMed1988

Torsion of a wandering spleen.

Splenic torsion is an uncommon cause of abdominal pain. It often leads to death and seldom has been diagnosed preoperatively. We report a patient in whom the anatomy of the lesion is illustrated, together with its predisposing factors and diagnostic features.

Humans↗
PubMed1987

Halothane anesthesia decreases human monocyte hydrogen peroxide generation. Protection of monocytes by activation with gamma interferon.

In an effort to determine the impact of halothane anesthesia on certain human cell-mediated immune functions, normal, purified human monocytes and lymphocytes were exposed to halothane in vitro at varying concentrations for up to 8 hours. Subsequently, these human effector cells were analyzed for their ability to function in several cell-mediated immunologic assays. Natural killer cell activity against K-562 was unaffected by halothane in most of the donors tested. Similarly, the ability of purified monocytes to inhibit MBL-2 tumor cell growth was unchanged. Halothane appeared to decrease the proliferative response of lymphocytes to phytohemagglutinin (PHA) in approximately 50% of the normal donors tested. In contrast, the ability of monocytes to lyse antibody-coated red cell targets (ADCC) was unaffected by even maximal exposure to halothane. Of interest was the finding that human monocytes exposed to as low as 2% halothane anesthesia for 4 hours displayed a dramatic down-regulation of hydrogen peroxide (H2O2) release. Since it is known that hydrogen peroxide and other incompletely reduced forms of oxygen secreted by monocytes can play a major role in the antimicrobial, antitumor, and inflammatory functions of these cells, this finding may help explain the enhanced susceptibility of post-operative patients to infections.

Adult↗
PubMed1987

A comparison of Golytely and standard preparation for barium enema.

A randomized prospective trial was performed comparing Golytely (with bisacodyl) with our standard two-day catharsis and bowel washout regimen as colon preparation for double-contrast barium enema examinations. Of the 107 patients who participated, 50 received the standard preparation and 57 Golytely. Two radiologists reviewed the enema films without knowledge of which preparation had been used. No significant difference was detected either in the number of failed preparations or in the quality. We conclude that routine use of Golytely is preferable to methods involving catharsis and standard tap water enemas for barium enema examination, on the grounds that it is equally effective, yet more convenient for patients and for the radiology department, and reduces total costs.

Barium Sulfate↗
PubMed1986

The effect of anesthetic agents on human immune system function. I. Design of a system to deliver inhalational anesthetic agents to leukocyte cultures in vitro.

A novel system for exposing purified human mononuclear leukocyte subsets or any cultured cell to inhalational anesthetic agents has been devised. Monocytes and lymphocytes are purified by counter-current centrifugal elutriation and put into culture vessels with and without appropriate functional activators. The culture vessels are placed into one of four anesthetic agent exposure chambers, each containing a different concentration of the anesthetic agent to be tested. The system that delivers the anesthetic agent to the culture vessels is essentially the same as the one used in the operating room; the actual levels of anesthetic agent delivered are monitored. In this report, we present evidence that halothane can be successfully tested using the above-cited experimental design; this agent substantially inhibits the secretion of interferon by human mononuclear cells. The ability of monocytes to secrete alpha interferon in response to polyinosinic: polycytidylic acid (poly I:C) was significantly depressed following 4 h in vitro exposure to increasing concentrations of halothane; the secretion of gamma interferon by lymphocytes in response to phytohemagglutinin (PHA) was also depressed, although to a lesser degree. The system presented should allow for the in vitro exploration of the effects of inhalational agents on purified human leukocyte subset functions as well as for the analysis of the effect of these agents on monocyte/lymphocyte interactions.

Halothane↗
PubMed1986

Driving ability after intravenous fentanyl or diazepam. A controlled double-blind study.

Uncomfortable or moderately painful radiologic diagnostic and therapeutic procedures are being performed increasingly on outpatients. If sedation and analgesia are used, patients cannot drive themselves home or return rapidly to normal activities. This study compares the effect of fentanyl (100 micrograms), diazepam (7.5 mg), and placebo on driving ability of young volunteers as measured by the thacometer. Speed and accuracy were impaired at 30 and 120 minutes by both drugs, and by fentanyl more than diazepam. This study design may be suitable for the assessment of whether patients can drive safely after other analgesic drugs.

Adult↗
PubMed1986

Comparison of endoscopy and barium swallow with marshmallow in dysphagia.

Forty-four patients with dysphagia were examined both by endoscopy and by barium swallow with a marshmallow bolus. In these patients 36 stenoses were found: 34 by radiology and 30 by endoscopy. The radiologic criteria for stenosis included arrest of the marshmallow in a manner to support a column of barium and reproduction of the patient's symptoms at the time this occurred. Radiologic false negative findings were partly due to an inability by patients to swallow an adequate marshmallow bolus; endoscopic failures were associated with small endoscopes and mild stenoses.

Barium Sulfate↗
PubMed1986

The combination of endoscopic sphincterotomy and percutaneous abscess drainage in the management of complicated biliary pancreatitis.

We report four patients with a protracted history of acute pancreatitis complicated by infected pseudocysts or abscesses. Ultrasonography showed that each patient had cholelithiasis. Endoscopic biliary sphincterotomy was performed resulting in the release of stones, gravel, or pus in all four cases. Three of the patients had successful percutaneous abscess drainage, and one patient was drained surgically. The abscesses all resolved, but one patient died suddenly of acute pulmonary embolism. The other three patients are well. We recommend this combined approach to pancreatic abscess drainage because, if there is obstruction to the flow of pancreatic juice at the ampulla of Vater, it is likely that the pancreatitis and abscess will fail to resolve.

Abscess↗
PubMed1985

Differential ability of human blood monocyte subsets to release various cytokines.

We have shown that two human monocyte subsets can be isolated from the peripheral blood of healthy donors; these subsets possess different morphological, cytochemical, functional, and in vivo trafficking properties [1]. In this report, these two subsets were further characterized. One subset (intermediate monocytes, IM) has been shown to have significantly lower acid phosphatase activity and total cellular protein content as well as lower peroxidase activity when compared with another subset (regular monocytes, RM). The overall activation status of the two subsets (as determined by their alkaline phosphodiesterase activity) was identical. We also examined the capacity of these subsets to release various cytokines with or without polyriboinosinic and polyribocytidylic acid (Poly I:C) stimulation. There was no appreciable difference in their ability to release interferon (IFN), interleukin 1 (IL-1), and prostaglandin E (PGE) without stimulation, while IM produced slightly, but significantly, higher amounts of colony-stimulating factor (CSF) than RM. The amount of IFN released by IM in response to poly I:C was approximately three times higher than the amount of IFN released by RM. IL-1 was also released in higher amounts by IM than by RM in response to poly I:C. IM were also found to release more CSF than RM in response to poly I:C. In contrast, it was noted that IM secrete significantly less PGE response to poly I:C than do RM. These findings indicate that two purified human monocyte subsets, distinguishable by maturation markers, differ significantly in their ability to release various cytokines after stimulation; this difference may be relevant to potential in vivo roles of these immunoregulatory cells.

Acid Phosphatase↗
PubMed1985

Rectal biopsy as a cause of rectal ulceration.

We report three patients in whom the performance of a rectal biopsy produced an ulcer that was found during a subsequent examination (two at double-contrast barium enema examinations and one at colonoscopy). In each case, the iatrogenic ulcers presented an unusual appearance and resulted in the performance of inappropriate follow-up studies.

Adolescent↗
PubMed1985

Pain after barium enema: effect of CO2 and air on double-contrast study.

One hundred fifty-one consecutive patients scheduled for double-contrast barium enema studies were assigned randomly to insufflation with either air or carbon dioxide (CO2) in a double-blind, prospective trial. Within 24 hours after the enema study, the patients were contacted by telephone by an interviewer, who completed a standard questionnaire. Radiographs from the enema studies were assessed for quality by two radiologists. Pain experienced after the procedure was graded from 0 (none) to 4 (severe). Clinically relevant (grades 2-4) pain was experienced by 30% of patients after insufflation with room air, compared with 11% of patients in whom CO2 was used for insufflation (P = .005). The mean pain score for CO2 was 0.4, and for room air, 1.2 (P less than .005). Although five patients experienced grade 4 pain after insufflation with air, no patient reported severe pain after CO2 insufflation. Post-evacuation films confirmed there was significantly less residual gas in the CO2 group. The quality of radiographs was equal in the two groups. CO2 has advantages for use in the double-contrast barium enema examination.

Air↗
PubMed1985

Microscopic lesions associated with the isolation of Haemophilus somnus from pneumonic bovine lungs.

Sixty-one of 68 sets of bovine lungs from which only Haemophilus somnus was isolated had microscopic lesions of purulent bronchiolitis and bronchopneumonia. In 37 of 61 lungs, the bronchiolar exudates were markedly necrotic with accompanying necrosis of the adjacent bronchiolar epithelium. Bronchiolitis obliterans was prominent in 23 of 28 lungs affected with chronic lesions with abscesses present in seven. Alveolar filling with inflammatory cells (neutrophils with fewer macrophages) was limited to peribronchiolar alveoli in 25 of 61 lungs and was multifocal to diffuse in the other 36. Lesions in the remaining lungs (7 of 68) were classified as fibrinous pneumonia with bronchiolitis (2), fibrinous pleuritis (2), suppurative interstitial pneumonia with vasculitis (2), and diffuse congestion (1).

Animals↗