Biomedical subjects
Publications and source records attributed to L T Weaver.
During a study of the intestinal permeability of newborn babies, three exhibited a sudden increase in lactulose absorption in association with the passage of bloody stools. An enhanced intestinal permeability may be an expression of the disruption of mucosal integrity in necrotising enterocolitis.
The bowel habit of 350 preschool children from a single general practice was studied. Eighty five per cent of 1 to 4 year olds eating a predominantly low fibre diet opened their bowels once or twice a day and 96% of the children fell within the range of three times a day to every other day. At all ages most children produced soft stools of about 25 ml volume. Mean intestinal transit time of 35 (10%) randomly selected children was 33 hours. There is a significant correlation between infrequency of bowel action, longer transit time, hard stools, and the passage of blood.
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Explore the source record for details and available documents.
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This paper discusses the conceptual categories used by the Baganda, to describe the events of normal and abnormal pregnancies. Kiganda knowledge of obstetrics is based upon observations of uterin size, foetal movements, amenorrhoea, vaginal bleeding and the delivery of the dead or alive foetus itself. This paper shows the relationship between Western obstetric categories, and those of the Baganda, and how, although the classification of the latter differs from that of the former in the terms used, it comprehensively descirbes all the types of normal and abnormal pregnancy that Western obstetrics recognizes.
Helicobacter pylori is probably the commonest bacterial infection of humankind. In adults, colonization of the stomach is associated with chronic gastritis and duodenal ulcer disease. However, children in the developing world acquire H. pylori soon after birth, and there is evidence that it plays a part, through suppression of the gastric acid barrier, in the pathogenesis of the syndrome of diarrhoea, malnutrition and growth failure. Infants born of mothers who secrete milk with high levels of anti-H. pylori immunoglobulin A (IgA) antibody acquire the infection later than those born of mothers with low specific antibody levels. Enhancement of maternal breast milk anti-H. pylori IgA levels may protect infants from H. pylori infection during the vulnerable weaning period when many are susceptible to enteric infections, leading to recurrent diarrhoea and adverse consequences on nutrition and growth.
The contrasting effects of natural versus cow's milk formula (CMF) on upper gastrointestinal development in the newborn were studied. The passive intestinal permeability of neonatal human infants and guinea pigs was measured using the nonmetabolisable markers lactulose and mannitol. Mucosal morphology was examined in guinea pigs by light microscopy. Nineteen full-term human infants and 63 guinea pigs were studied during the 1st week of extrauterine life. The naturally fed infants showed a decline in intestinal permeability to lactulose following the onset of feeding. This was not shared by those fed CMF. The CMF-fed guinea pigs showed a persistently higher intestinal permeability than the naturally fed animals throughout the 1st week of life. No differences were observed in the villous heights or crypt depths between feeding groups, but both showed an increase in intraepithelial lymphocyte number during the 1st week. Cow's milk formula may cause a persistently higher intestinal permeability, or natural feeding may promote a decline in permeability in the enterally fed newborn.
The effect of intrapharyngeal infusion and subsequent passage of the lectin concanavalin A through the gastrointestinal tract of neonatal guinea pigs was examined. The lectin, administered at a concentration of 1 mg/ml, caused considerable mucosal damage in the stomach. Subsequent passage of the lectin through the small intestine caused little cellular damage to the mucosa, as judged by light and electron microscopy. Parallel morphometric analyses of the jejunum showed a decrease in mean villus height and an increase in mean crypt depth of 8% after 5 h of lectin administration. A 4.7-fold increase in jejunal crypt cell production rate was observed, accompanied by a statistically significant increase in the number of intraepithelial lymphocytes. These morphologic and kinetic changes were accompanied by a three-fold increase in the urinary lactulose:mannitol excretion ratio, indicative of a loss of mucosal integrity. No systemic antibody response to concanavalin A was demonstrated within 5 h of intragastric infusion of the lectin. Concanavalin A, conjugated with 10 nm colloidal gold particles, was also directly infused into the lumen of the jejunum in vivo. Within 60 min, both villous and crypt epithelial cells contained gold particles, demonstrating the rapid accessibility of crypt cells to the lectin. Intercellular spaces appeared within the villous epithelium, although both junctional complexes and spot desmosomes were retained. The brush border was abnormal with signs of incipient vesicularization. These findings have implications for our understanding of the pathogenesis of childhood coeliac disease and for the vulnerability of the neonatal gut to food proteins.
A prospective study of the bowel habits of 240 infants aged 2-20 weeks was performed. Half of the infants were breast fed and half were fed cow's milk formula (CMF). Breast-fed infants had a higher mean frequency of defaecation than did CMF-fed infants at 2, 4 and 8 weeks (p less than 0.02). By 16 weeks the mean frequency of bowel actions per day of infants of both feeding groups was 2. With increasing age, infants produced fewer stools of greater firmness (p less than 0.05) though the breast fed tended to pass larger, softer stools than did the CMF-fed infants until the introduction of weaning foods (p less than 0.05). Stool colour was uniformly yellow in both feeding groups until the introduction of weaning foods, when it changed to brown. Weaning foods were introduced at an earlier age in the CMF-fed infants (p less than 0.05), though by 20 weeks 93% of all infants had received some. These data define the normal range of the bowel habits of milk-fed infants and may reflect differences in gastrointestinal function between those fed on the breast and with CMF.
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We expect that most pregnancies will bear normal babies, which will grow up into healthy young adults free of the risk of serious disease. We also believe that many common diseases and causes of death in adulthood may be preventable through changes in living conditions, diet and lifestyle. The 20th century saw a massive decline in childhood mortality and morbidity as well as improvements in child health. The relations between environmental influences and genetic endowment in the genesis of disease are ever clearer, and at their 'extremes' susceptible to interventions. The burden of infectious disease has been reduced to 5% of what it was a century ago, and many chromosomal and monogenic diseases can be avoided or their effects ameliorated before or soon after birth. Nevertheless, there is strong evidence that poor environmental conditions are the principal determinants of ill health at all stages of life, and it follows that the optimal time to intervene to correct them is in early life. Moreover, we recognise the principal risk factors for chronic adult disease, and also have the tools to measure genetic susceptibility to them. There is, therefore, hope that as their natural history becomes better defined, they will be increasingly preventable or treatable. The challenge to paediatricians now is to ensure that children are not only born healthy and remain healthy, but also grow up to be healthy adults. When it is increasingly clear that the origins of many adult diseases are in childhood or before, paediatricians should strive to work closely with their colleagues in primary care, public health, clinical genetics, education, government, housing, environmental and social services, toward the common goal of promoting optimum health throughout the fullness and completeness of life.
Study of the effects of enteral nutrition on neonatal growth and development has been hindered by lack of a suitable model. An isotope dilution method for the measurement of milk intake in suckling rodents was evaluated in 13 hand-fed neonatal guinea pigs, by comparing milk intakes determined using 3H20 with intakes determined by difference in weight before and after feeding. The effects of two experimental durations (1 or 2-3 days) on the accuracy and precision of the method was assessed. Weighted milk intakes were 18 -26 g/day, and body weight changes were -7% - +12% of initial weight. There was no significant difference between milk intakes determined using the two methods for both 1 and 2-3 day comparisons. However, the coefficients of variation for 1 and 2-3 day measurements were 24.4% and 5.5%, respectively. These values are equivalent to precisions of approximately 10% and 2% for estimates of total milk output in a rodent suckling 8 pups. It is concluded that the 3H20 method is no less accurate or precise than the weighing method for 2-3 day measurements of milk intake in individual pups and milk production of dams. These findings strengthen the use of the precocial guinea pig as a model for the study of the effects of early feeding on growth, development and aging.