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Biomedical subjects

G P Davidson

Publications and source records attributed to G P Davidson.

At least 19 recordsLinked to original sources
PubMed1979

Structural and functional abnormalities of the small intestine in infants and young children with rotavirus enteritis.

Structural and functional alterations in duodenal mucosa from 17 children with rotavirus enteritis were assessed. Structural changes were found in specimens from all patients. Patients with the most severe mucosal damage were more likely to require intravenous therapy to correct dehydration. Depression of one or more mucosal disaccharidases was found in 14 of 16 patients. Repeat duodenal biopsy three to eight weeks later in six patients showed marked improvement. The study clearly shows that rotavirus can cause a marked structural and functional lesion in the upper small intestine which is rapidly reversible.

Acute Disease↗
PubMed1979

The spectrum of cow's milk allergy in childhood. Clinical, gastroenterological and immunological studies.

Seventeen of 52 children suspected of having cow's milk allergy had this diagnosis confirmed after milk challenge in hospital. A broad spectrum of reactions was obsserved including skin eruptions, respiratory symptoms and gastrointestinal disturbance. Not all patients with gastrointestinal symptoms showed small bowel mucosal damage. Only patients with skin reactions had positive skin tests. IgA deficiency and IgE elevation were common. Four patients had symptoms within 3 days of birth. Twelve children tolerated cow's milk by three years of age. Cow's milk allergy can cause a variety of symptoms. Challenge with milk for several days may be required before allergic manifestations can be demonstrated.

Animals↗
PubMed1978

MCQ assessment of introductory clinical course for fourth year medical students.

A 60-item MCQ as administered to 46 fourth year medical students at the beginning, half-way, and at the end of a five week introductory clinical course. The stated goals were achieved: (1) a baseline measure was provided, indicating abilities brought by newly-arriving students; (2) data gave opportunity for "mid-course" corrections by students in their study and by tutors in their teaching; (3) overall student change was assessed, offering a measure of the educational effectiveness of the course, and (4) tutors were made aware of individual students requiring particular attention. Such assessment techniques provide an effective monitoring and motivating instrument at this level of medical education.

Education, Medical, Undergraduate↗
PubMed1978

Salivary amylase in cystic fibrosis: a marker of disordered autonomic function.

Total serum amylase was determined in 83 patients with cystic fibrosis (CF) (14 of whom had no steatorrhea), 21 control patients, and 6 patients with Shwachman's syndrome. Patients with CF who had steatorrhea and therefore lacked pancreatic function had the same serum levels pre- and postprandially as the control subjects, whereas patients without steatorrhea and, therefore, with evidence of pancreatic function, had significantly higher levels. The patients with Shwachman's syndrome had significantly lower total serum amylase than the three other patient groups. Only the patients with Shwachman's syndrome demonstrated a significant postprandial rise in activity. Only the salivary isoenzyme was detected in patients with Shwachman's syndrome or CF and apparently absent pancreatic function, whereas CF patients without steatorrhea had both salivary and pancreatic isoenzymes. These results demonstrate that patients with CF have an increase in circulating salivary amylase isoenzyme whereas patients with Shwachman's syndrome do not. The increase probably reflects an autonomic hyperstimulation of salivary secretion which is primary to CF, and unrelated to the state of pancreatic activity.

Amylases↗
PubMed1978

Familial enteropathy: a syndrome of protracted diarrhea from birth, failure to thrive, and hypoplastic villus atrophy.

We have studied 5 infants with persistent severe diarrhea from birth and marked abnormalities of absorption associated with failure to thrive leading to death in 4 infants. Three had siblings who died and a sibling of a 4th is ill at present, all with a similar illness; 2 were the products of consanguinous marriages. Exhaustive investigation failed to identify a recognized disease entity in any patient. Steatorrhea, sugar malabsorption, dehydration, and acidosis were severe in all patients, whatever the diet fed. Total parenteral nutrition was used, but excessive stool water and electrolyte losses persisted even when nothing was fed by mouth. There was no evidence of a hematological or consistent immunological defect in any infant and no abnormalities of intestinal hormones were noted. In the duodenal mucosa of all infants we saw similar abnormalities characterized by villus atrophy, crypt hypoplasia without an increase in mitoses or inflammatory cell infiltrate in the lamina propria and in villus enterocytes absence of a brush border, increase in lysosome-like inclusions, and autophagocytosis. In 3 infants studied by marker perfusion of the proximal jejunum we found abnormal glucose absorption and a blunted response of Na+ absorption to actively transported nonelectrolytes; in 2 there was net secretion of Na+ and H2O in the basal state. Our patients evidently suffered from a congenital enteropathy which caused profound defects in their capacity to assimilate nutrients. The similar structural lesion seen in the small intestinal epithelium of all of our cases undoubtedly contributed to their compromised intestinal function, but the pathogenesis of this disorder, if indeed it is a single disease, remains obscure.

Acidosis↗
PubMed1978

Self-hypnosis training in anxiety reduction.

Twenty three adult patients with problems of anxiety in a suburban general practice were invited to participate in a study to determine the effectiveness of self-hypnosis training in reducing anxiety levels. In an initial interview (T1), Experimenter 1 gave subjects two C-60 cassette tapes for home use. These contained the voice of Experimenter 2 who was unknown to the subjects, instructing them in self-hypnosis. After six weeks (T2), measures by Experimenter 1 of both psychological anxiety and blood pressure showed significant reduction (with the exception of systolic blood pressure), and in some cases subjects reduced their anxiolytic medication. A follow-up nine months later of as many subjects as were available (12) showed that these desirable effects were still detectable to a significant degree. It is suggested that audiotaped training in self-hypnosis represent a valid non-pharmacological method for anxiety reduction.

Adult↗
PubMed1977

Structural and functional abnormalities of the small intestine due to nutritional folic acid deficiency in infancy.

Structural abnormalities and disaccharidase deficiency were demonstrated in biopsies of duodenal mucosa from four infants who had symptoms of failure to thrive and chronic diarrhea associated with a megaloblastic anemia. Goat's milk was the main dietary constituent for each infant for six to eight months prior to presentation. The structural abnormalities consisted of villous blunting, crypt hypertrophy, megaloblastic changes in epithelial cells, and nuclear enlargement. All changes reverted to normal with the addition of folic acid to the diet. This study provides evidence that nutritional folic acid deficiency can cause structural and functional alterations of the small intestine in infants.

Anemia, Megaloblastic↗
PubMed1977

Complement-fixing antibody response to rotavirus infection.

A human rotavirus complement-fixing (CF) antigen, prepared by purification of large volumes of fluid feces collected from children with winter diarrhea, was used to study the development and persistence of antibody in children with diarrhea and the prevalence of rotavirus antibody in Melbourne. In children with diarrhea, antibody rises were detectable within 4 to 6 weeks of the onset of illness, and the titers usually remained elevated for the next 1 to 2 years. CF antibody did not develop in two children with proven rotavirus infection aged less than 6 months, an age at which poor CF responses to other viruses have also been observed. A study of CF antibody levels in the general community showed that in Melbourne, most children have been infected with human rotavirus by the age of 3 years.

Age Factors↗
PubMed1977

Human rotavirus enteritis induced in conventional piglets. Intestinal structure and transport.

To better understand the pathogenesis of infantile viral gastroenteritis, we studied Na+ and Cl- fluxes in vitro in short-circuited jejunal epithelium from 8-10-day-old piglets after infection with a standard dose of human rotavirus given via nasogastric tube. 11 infected piglets, all of whom became ill, were compared with 9 uninfected, healthy litter-mates. When killed 72 h after infection, intestinal villi were shorter and crypts deeper (P less than 0.025) in duodenum, upper jejunum, and mid-small intestine, but not ileum in infected piglets. Virus antigen was seen by fluorescence microscopy in occasional jejunal villus tip cells in only four infected piglets and no controls at 72 h. Net Na+ and Cl- fluxes did not differ from noninfected litter-mate controls under basal conditions, but response to glucose was blunted in infected piglets (P less than 0.001). Theophylline stimulated net Cl- secretion in both infected and control animals, and cyclic AMP concentration in isolated jejunal villus enterocytes did not differ significantly. In isolated jejunal villus enterocytes of infected piglets, thymidine kinase activity increased (P less than 0.001), and sucrase activity decreased (P less than 0.001). We conclude that in this invasive enteritis caused by a major human viral pathogen, glucose-coupled Na+ transport is impaired in the jejunum at a time when the villus epithelium shows enzyme characteristics of crypt epithelium, and when little or no virus is present. These findings are identical to those occurring in an invasive coronavirus enteritis of piglets but differ markedly from those seen with enterotoxigenic diarrhea.

Animals↗
PubMed1976

Gastrointestinal milk allergy in childhood: a rational approach.

Nine children with "unequivocal symptoms attributable to cow's milk allergy" were referred for assessment. Detailed gastrointestinal and immunoallergic investigations confirmed this diagnosis in only one case. In three of the children an abnormality of sucrose absorption was detected by disaccharidase assay. The results of this study indicate the need for cow's milk provocation under controlled conditions before the diagnosis of gastrointestinal cow's milk allergy can be made. A protocol for the assessment of children with suspected cow's milk allergy is proposed.

Animals↗
PubMed1976

New virus associated with diarrhoea in neonates.

Since December, 1974, there has been an increase in the incidence of acute diarrhoea in the neonatal nurseries of five Melbourne metropolitan hospitals. Four of these have had epidemics, and the incidence of endemic diarrhoeal disease has increased. Extracts of faeces from 148 patients from the five hospitals were examined by electron microscopy. "Duovirus" particles were detected in 82 of these extracts, including at least one from each hospital. No bacterial pathogens were isolated. It seems likely that "duovirus" is an important cause of sporadic and epidemic acute diarrhoeal disease in neonates. It is important to note that the absence of a recognized bacterial pathogen does not exclude an infective cause, especially when sugar intolerance is present. Appropriate measures to minimize the spread of infection must be employed.

Acute Disease↗
PubMed1976

Reversible intestinal mucosal abnormality in acrodermatitis enteropathica.

In 3 cases of acrodermatitis enteropathica duodenal biopsy performed at the outset of treatment showed a similar abnormality of the intestinal mucosa. Further biopsies taken during treatment showed progressive improvement of the intestinal mucosa with subsequent complete restoration of the normal cellular and villous pattern. The initial treatment was with expressed human breast milk and oral di-iodohydroxyquinoline. The latter was continued alone and later replaced by zinc sulphate. Changes in the intestinal epithelial cells and inflammatory cell infiltration of the lamina propria still detectable on di-iodohydroxyquinoline therapy reverted to normal with oral zinc.

Acrodermatitis↗