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Biomedical subjects

G W Stevenson

Publications and source records attributed to G W Stevenson.

At least 91 records · Page 5Linked to original sources
PubMed1989

The effect of glucagon on esophageal peristalsis and clearance.

The effect of 0.5 mg intravenous glucagon on esophageal peristalsis and transit of water and barium was studied in nine healthy subjects by concurrent videofluoroscopy and manometry. Glucagon lowered manometric peristaltic amplitude in both mid- and distal esophagus. This reached significance (p = 0.0075) in the distal 3 cm of the esophagus 2 min after the injection. The efficiency of esophageal stripping was also reduced (increased proximal escape on fluoroscopy), and became significant (p = 0.05) at 2 min after the injection of glucagon.

Adolescent↗
PubMed1989

Defecography in normal volunteers: results and implications.

Forty seven healthy young volunteers underwent defecographic examination to determine the range of normal findings. Normality was shown to encompass radiological features often considered pathological. These features included broad ranges of anorectal angle and pelvic floor descent which overlap with reported pathological states. Furthermore, the formation of rectocoeles during defecation was a very common finding in women. Finally, a subgroup of the volunteers had marginal anorectal function. The marginal anorectal function and certain radiological findings such as rectocoeles or intussusceptions may predispose to later problems, or contribute to clinical problems when combined with other factors such as dietary fibre deficiency. The radiological findings raise a number of questions with respect to different aspects of the functioning of the continence and defecation mechanisms.

Adult↗
PubMed1989

Interobserver variation in the interpretation of abdominal radiographs.

A total of 140 sets of abdominal radiographs were reviewed independently by four qualified diagnostic radiologists. The degree of interobserver agreement was determined by calculating kappa values for 19 commonly used radiographic signs and diagnoses. There was fair to excellent interobserver agreement for 11 signs and diagnoses and poor agreement for the remaining eight. The signs and diagnoses for which agreement is poor cannot be considered reliable and include particularly large bowel obstruction and nonspecific gas pattern.

Humans↗
PubMed1989

Defaecography: setting up a service.

Defaecography is a simple procedure to perform and provides morphological information on the mechanism of defaecation from which physiological parameters can be inferred. This article discusses the value of the technique, and aims to give practical help to those considering introducing such a service.

Barium Sulfate↗
PubMed1988

Effects of adherence, activation and distinct serum proteins on the in vitro human monocyte maturation process.

Elutriator-purified human monocytes were cultured in a serum-free (SF) medium, and various serum proteins and functional activating agents were assessed for their effects on the in vitro maturation of human monocytes to macrophages. Following 3 days of suspension culture in Teflon labware, 60% of the monocytes were easily recovered. When varying concentrations of human AB serum (HuAB) were employed, human monocyte maturation progressed rapidly; the kinetics of this maturation process during cell suspension culture were very similar to the pattern observed following adherence culture. In contrast, when SF medium was employed, a marked retardation of the monocyte maturation process was observed; this could not be attributed to any changes in cell recovery and/or viability. Thus, cells could be maintained in their monocytoid form for 3 days when cultured in SF medium. When HuAB was added after 3 days of culture, human monocyte maturation into macrophages proceeded at a normal rate. We attempted to characterize certain of the serum protein(s) found in HuAB which promoted the monocyte maturation process. Human immunoglobulin G (IgG) was found to be the most potent serum protein in increasing 5'-N activity and decreasing peroxidase activity of suspension cultured monocytes. Immunoglobulin M (IgM) and albumin (Alb) were shown not to have significant monocyte maturation activity. Heat-treated human gamma globulin and IgG purified by high-performance liquid chromatography (HPLC) were shown to have patterns identical with that of untreated HGG and IgG with regard to promoting monocyte maturation; F(ab')2 was not an active maturation promoter, indicating the need for an intact Fc portion of the IgG molecule. Fibrinogen and fibronectin also had maturation promoting activity. Finally, addition of the potent monocyte functional activators, muramyl dipeptide (MDP), polyriboinosinic:polyribocytidilic acid (Poly I:C), and lipopolysaccharide (LPS) had no effect on the monocyte maturation process. Thus, neither cell adherence or activation appear to be critical for the monocyte to macrophage maturation process. Instead, we hypothesize that in addition to proper nutritional support, a group of serum proteins (unified mainly by their ability to interact with monocyte membrane receptors) appear to be the principal promoters of this process.

5'-Nucleotidase↗
PubMed1988

Radiological appearance of migrating motor complex of the small intestine.

During fasting, a cyclical pattern of rhythmic peristaltic motor activity is known to occur in the small intestine. It is called the migrating motor complex (MMC), and periodically sweeps the small bowel of secretions. It is usually abolished by feeding. This report is the first description of an MMC observed during the fluoroscopic examination of a patient during a small bowel examination.

Fasting↗
PubMed1988

Colorectal polyps: a correlation of radiological and pathological findings.

Ninety colorectal polyps seen on double contrast barium enema were reviewed and note was made of surface and base characteristics, size, site and the presence of associated disease. Results were then correlated with the histology. The radiological characteristics of each histological type of polyp encountered are described. Because of the variation in radiological appearance of each histological type and similarities in appearance between these types, we conclude that radiology cannot accurately predict the histology of a colorectal polyp.

Adult↗
PubMed1988

The treatment of cancer with activated cytotoxic leukocyte subsets.

Cancer biotherapy focuses on stimulating natural defense mechanisms designed to control or eradicate cancer. Many distinct cancer biotherapy strategies have been formulated over the past two decades; one of the most promising involves the removal of cytotoxic leukocyte subsets from cancer patients, augmenting the cytotoxic function of these cells ex vivo and re-administering these activated cells with additional function-enhancing biologicals. This approach is termed adoptive cellular immunotherapy and is best represented at present by the activated killer monocyte and the lymphokinc activated killer cell therapies. The activation of cytotoxic monocytes with gamma interferon and the activation of cytotoxic lymphocytes with interleukin-2 are prototypic examples of adoptive immunotherapy research activity which is likely to expand in the near future.

Drug Evaluation↗