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Biomedical subjects

G D Kerr

Publications and source records attributed to G D Kerr.

At least 37 records · Page 2Linked to original sources
PubMed1988

Ambulatory pH monitoring of gastro-oesophageal reflux in "morning dipper" asthmatics.

A causal relation between gastro-oesophageal reflux and nocturnal asthma has been postulated. Forty four adult asthmatics underwent ambulatory monitoring of their oesophageal pH over 24 hours to find out if there was such a relation. Of these 21 showed significant "morning dipping" in which the peak expiratory flow falls during the night. Asthmatics with morning dipping had a history of nocturnal wheeze and a higher incidence of reflux symptoms, but measurement of oesophageal pH showed no significant difference in the amount or pattern of reflux when compared with "non-dippers." Overall, 15 asthmatics had gastro-oesophageal reflux, and these participated in a randomised, double blind crossover trial of ranitidine versus placebo. No significant difference was found in the peak expiratory flow rates or subjective evaluation of well being of the patients.

Adult↗
PubMed1988

Quality factors.

The quality factor, Q, is a dimensionless modifier used in converting absorbed dose, expressed in gray (or rad), to dose equivalent, expressed in sievert (or rem). The dose equivalent is used in radiation protection to account for the biological effectiveness of different kinds of radiation. The quality factor is related to both linear energy transfer (LET) and relative biological effectiveness (RBE). The RBE obtained from biological experiments depends in a complex way on the observed biological effect, the specific test organism and the experimental conditions. Judgment is involved, therefore, in the choice of Q. Questions regarding the adequacy of current Q values for neutrons were first raised in a 1980 statement by the National Council on Radiation Protection and Measurements (NCRP) and later in a 1985 statement by the International Commission on Radiological Protection (ICRP). In 1980, the NCRP alerted the technical community to the possibility of a future increase between a factor of 3 to 10 in the Q for neutrons, and in 1985, the ICRP suggested an increase by a factor of 2 in Q for fast neutrons. Both these advisory groups are now recommending essentially the same guidance with regard to Q for neutrons: an increase by a factor of 2. The Q for neutrons is based on a large, albeit unfocused, body of experimental data. In spite of the lack of focus, the data supporting a change in the neutron quality factor are substantial. However, the proposed doubling of Q for neutrons is clouded by other issues regarding its application. These issues are discussed, together with the current database for the neutron quality factor. Improvements are needed to provide better guidance with regard to both Q for neutrons and its application in radiation protection.

Animals↗
PubMed1987

Acid suppression in duodenal ulcer: a meta-analysis to define optimal dosing with antisecretory drugs.

FVMany different dosage schedules of antisecretory drugs for the treatment of duodenal ulcer are recommended. The relationship between degree of acid suppression and therapeutic efficacy has not been precisely defined for these drugs. We have examined the association between suppression of intragastric acidity and duodenal ulcer healing rates for a number of therapeutic regimens. For the H2 receptor antagonists alone, the most significant correlation with healing rates was with suppression of intragastric acidity at night (r = 0.926; p = 0.0001). When other classes of drug: high dose antacid, omeprazole and a synthetic prostaglandin (enprostil) were included in the analysis, the closest correlation was with suppression of total 24 hour intragastric acidity (r = 0.911; p less than F0.0001). Stepwise linear regression analysis was used to investigate the relative contributions to healing of suppression of acidity during the day and night. Suppression of nocturnal acidity was found to be the single most important factor in explaining healing rates. No further benefit was obtained with daytime suppression for H2 receptor antagonists; suppression of acidity at night accounted for 86.1% of the observed variation in healing rates among different regimens of H2 receptor antagonists. When all classes of drugs were analysed, inclusion of daytime suppression produced a significant improvement in correlation over nocturnal suppression alone. Drug regimens providing potent suppression of nocturnal acidity produce the highest healing rates in controlled clinical trials. The healing rate for any dose regimen of an antisecretory drug can be predicted from a knowledge of its effect on intragastric acidity. For the H2 receptor antagonists, suppression of nocturnal acidity is the most relevant in this context. Moderate suppression of acidity achieves ulcer healing rates at four to eight weeks which are comparable with those seen with potent suppression at two to four weeks. Increasing degrees of suppression merely accelerate healing.

Anti-Ulcer Agents↗
PubMed1986

The correlation between acid suppression and peptic ulcer healing.

Suppression of gastric acid forms the basis of treatment of duodenal and gastric ulcer, but the precise relationship between suppression of acidity and healing rates has not been defined. We examined the results of controlled trials and clinical pharmacological studies of 24-h intragastric acidity involving antisecretory agents. Data on 24-h and nocturnal hydrogen ion activity and nocturnal acid output were obtained, and the healing rates in duodenal ulcer were calculated. Duodenal ulcer healing rates after 4 weeks showed a significant correlation with suppression of 24-hour hydrogen ion activity (r = 0.63; P less than 0.05), and a highly significant correlation between healing and the suppression of nocturnal hydrogen ion activity (r = 0.93; P less than 0.0001). Nocturnal acid output was not significantly correlated. For gastric ulcer, no such association was seen for suppression of either 24-hour or nocturnal hydrogen ion activity. Duodenal ulcer is regarded as an acid-related disorder, but in gastric ulcer other factors may be more important in pathogenesis and treatment.

Anti-Ulcer Agents↗
PubMed1981

Dietary allergy and specific IgE in ulcerative colitis.

Previous authors have considered that allergy to certain foodstuffs may play an important role in the aetiology of ulcerative colitis, but immunological evidence for dietary allergy in ulcerative colitis is inconclusive. A study is reported of 22 patients with ulcerative colitis, with matched controls, in whom total serum IgE and specific IgE to certain foodstuffs have been estimated by the Phadebas PRIST and RAST (Pharmacia) techniques. Allergens tested were egg-white, milk, wheat, rye, oat, fish (cod) and peanut. There was no significant difference in the total serum IgE levels and the food specific IgE activity between the two groups.

Adult↗
PubMed1977

Imaging of acute myocardial infarction using technetium 99m labelled phosphate compounds.

Technetium 99m pyrophosphate or polyphosphate administered intravenously soon after acute myocardial infarction produces positive images of the area and extent of myocardial necrosis. Forty-four patients have been studied of whom 39 had myocardial infarction. There was good correlation of the site and extent of infarction as indicated by the scintigram with electrocardiogram and cardiac enzyme criteria.

Acute Disease↗