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Biomedical subjects

I W Booth

Publications and source records attributed to I W Booth.

At least 19 recordsLinked to original sources

Doppler assessment of human neonatal gut blood flow velocities: postnatal adaptation and response to feeds.

Duplex pulsed Doppler ultrasound was used to study changes in gut blood flow velocities during the first week of life in a group of 14 term babies. There was a significant increase in fasting peak systolic velocity in the superior mesenteric artery between days 1 and 2 with a further upward trend until day 5; no such changes were seen in the coeliac axis. Fasting velocities were 20% lower in breast-fed babies than bottle-fed babies. Following feeds, there was a significant increase in velocity in the superior mesenteric artery that was 35% greater in the bottle-fed than breast-fed babies. Changes in the coeliac axis were qualitatively similar but substantially smaller. The peak velocity in both vessels occurred 50 min after a feed. We conclude that Doppler ultrasound can be readily used to measure gut blood flow velocities in the human newborn. It provides a noninvasive technique for investigating adaptive postnatal changes in the splanchnic circulation, and, in particular, the response to feeds.

Adaptation, Physiological

Abnormal gut blood flow velocities in neonates at risk of necrotising enterocolitis.

Duplex pulsed Doppler ultrasound was used to determine blood flow velocities in the coeliac axis and superior mesenteric artery in three groups of neonates: a group at high risk of developing necrotising enterocolitis (n = 27) and two control groups, i.e., a nonasphyxiated, appropriately grown group of preterm infants (n = 18) and a group of nonasphyxiated term infants (n = 14). Subjects were studied on the first, second, and fourth days of life. The median peak systolic velocities in the superior mesenteric artery were between 20 and 51% lower in the at-risk group than in the term control group on all 3 days of measurement (p less than 0.05-p less than 0.002). The ratio of peak systolic velocity in the coeliac axis to that in superior mesenteric artery, an index of relative downstream vascular resistance in the superior mesenteric artery, was 42-65% greater in the at-risk group compared with the other two groups on days 1 and 2 (p less than 0.05-p less than 0.001) and significantly greater than the term group on day 4 (73%, p less than 0.002). These data demonstrate that neonates at risk of developing necrotising enterocolitis have abnormal gut blood flow velocities. Furthermore, they provide evidence that an alteration in the splanchnic circulation may be an important factor in the final common pathway that links diverse risk factors for necrotising enterocolitis with clinical disease.

Blood Flow Velocity

Congenital sodium diarrhea with a partial defect in jejunal brush border membrane sodium transport, normal rectal transport, and resolving diarrhea.

Defective jejunal sodium/proton exchange causes severe, congenital secretory diarrhea. We report a boy who presented typically in utero, but in whom diarrhea resolved during the first year of life. Pregnancy was complicated by polyhydramnios, and an ultrasound at 31 weeks showed a distended fetal small intestine. The abdomen was grossly distended at birth, and profuse secretory diarrhea began immediately. He subsequently thrived on breast milk and electrolyte supplements. Studies of jejunal brush border sodium/proton exchange at 6 months showed a partial defect. Nonequilibrium rectal dialysis showed rectal sodium and potassium transport to be intact. Diarrhea lessened after 9 months, and the patient subsequently required occasional laxatives. These observations suggest that there is a spectrum of congenital abnormality in this exchanger, and that in children with incomplete defects normal colonic sodium salvage can subsequently mask net small intestinal secretion.

Biological Transport

Elevated short chain fatty acid concentrations in anaerobic small bowel contamination.

Viable bacteria were identified and counted, and short chain fatty acid concentrations measured in small intestinal fluid from 74 fasting children. In nine children with anaerobic small bowel contamination, individual and total short chain fatty acid concentrations were significantly higher than the remainder of the group (p less than 0.01). Using 100 mumol/l as the upper reference limit for total short chain fatty acid concentration, the sensitivity and specificity as a test for anaerobic small bowel contamination was 89% and 98%, respectively. Measuring luminal short chain fatty acid concentrations in proximal small intestinal fluid is an accurate method for detecting anaerobic small bowel contamination in children.

Adolescent

Hazards of parenteral treatment: do particles count?

After prolonged parenteral nutrition a 12 month old infant died with pulmonary hypertension and granulomatous pulmonary arteritis. A review of necropsy findings in 41 infants who had been fed parenterally showed that two of these also had pulmonary artery granulomata, while none of 32 control patients who died from sudden infant death syndrome had similar findings. Particulate contaminants have been implicated in the pathogenesis of such lesions and these were quantified in amino acid/dextrose solutions and fat emulsions using automated particle counting and optical microscope counting respectively. Parenteral feed infusions compounded for a 3000 g infant according to standard nutritional regimens were found to include approximately 37,000 particles between 2 and 100 microns in size in one day's feed, of which 80% were derived from the fat emulsion. In-line end filtration of intravenous infusions may reduce the risk of particle associated complications. A suitable particle filter is required for use with lipid.

Arteritis

Persistent gastrointestinal symptoms after correction of malrotation.

Persistent vomiting, diarrhoea, or intolerance of feeding, are well recognised problems in children after surgical correction of intestinal malrotation. Conversely, intestinal malrotation is a common accompaniment of chronic idiopathic intestinal pseudo-obstruction. We investigated motor activity of the small intestine during fasting in eight children who had persistent vomiting, intolerance of full enteral feeding, or severe diarrhoea after surgical correction of intestinal malrotation. Abnormality of motor function similar to that found in neuropathic pseudo-obstruction was found in seven of the eight patients. Persistence of symptoms after surgical correction of a malrotation is associated with a motility disturbance which seems to be due to a defect of intrinsic enteric innervation. Such a defect may be important in the aetiology of the malrotation.

Child, Preschool

Intensive enteral feeding in advanced cirrhosis: reversal of malnutrition without precipitation of hepatic encephalopathy.

Ten children with advanced cirrhosis and malnutrition (less than 90% weight for height) were fed for eight weeks with a nasogastric feed comprising whey protein (enriched with branched chain amino acids), fat as 34% medium chain and 66% long chain triglycerides, and glucose polymer. Six of the children were studied for an eight week control period before feeding. Weight, triceps skinfold thickness, mid-arm circumference, mid-arm muscle area, and fasting plasma ammonia and amino acid concentrations were measured before and after the control period and after the consequent feed period. Results showed that despite high energy and protein intakes the children remained malnourished over the control period. All anthropometric indices improved significantly during the feed period, and no child developed clinical encephalopathy. The feed period was associated with a small, and not clinically significant, increase in the plasma ammonia concentration, but no consistent trend in the plasma amino acid concentrations. Thus, in children with advanced hepatobiliary disease awaiting liver transplantation, enteral feeding improved nutritional status without adverse clinical or biochemical effects.

Amino Acids

Using the steatocrit to determine optimal fat content in modular feeds.

The steatocrit was measured in infants with protracted diarrhoea who were receiving intragastric modular feeds. Measurements were made when fat intake was constant to determine steatocrit variability and during increases in fat intake to determine fat tolerance limits. Steatocrit variability was expressed as the range between a subject's lowest and highest steatocrit value. The median between-stool and between-day variabilities were 2% and 11% respectively. Variability was also measured in seven healthy breast fed infants. In the five still displaying appreciable physiological steatorrhoea, the between-day variability (median 8%) and between-stool variability (median 9%) were not significantly different from the protracted diarrhoea group. In the fat tolerance investigations in the protracted diarrhoea group, the steatocrit increased with increases in the module fat content. Fat intake and steatocrit were significantly positively related. A significant negative correlation was seen between steatocrit and weight gain, the latter becoming negligible at steatocrit values around 30%.

Breast Feeding

The steatocrit: an improved procedure.

The steatocrit is a simple and easily repeated assay for measuring the fat content of infants' stools. However, we and others have experienced technical difficulties in its use. Three modifications were therefore made to the original procedure: incorporation of a lipid-soluble dye, improved homogenization and a heating step. The modified method was used to measure the stool fat content of young children with and without clinical steatorrhoea. Validation of the modified steatocrit is presented, together with examples of its application to both clinical research and clinical practice.

Celiac Disease

The nature of small bowel luminal fluid lactase.

The evidence indicating a mucosal source for the jejunal fluid lactase activity of children is so far inconclusive. Samples of jejunal mucosa and the adjacent fluid were obtained simultaneously from 15 children. Lactase activity was measured at pH 5.9 in mucosa and fluid. Fluid activities showed a significant positive correlation with the activity of the corresponding mucosal homogenate but a stronger correlation was found with an enterocyte microvillous membrane fraction prepared from the same homogenate (r = 0.807 and 0.889, respectively). Kinetic and pH optima studies were consistent with a microvillous membrane origin. Fluid activity and pH optimum were not changed detectably when measured in the presence of an enterocyte lysosomal acid lactase inhibitor. Jejunal fluid lactase activity and its properties closely reflect the microvillous membrane enzyme. Lysosomal acid lactase does not contribute measurably to the total lactase activity of jejunal fluid.

Adolescent

Malnutrition at diagnosis of malignancy in childhood: common but mostly missed.

A prospective, controlled study of nutritional status in 100 newly diagnosed paediatric oncology patients is reported. Results showed that although patients' height-for-age and weight-for-height were normal, mid-upper arm circumference (MUAC) and triceps skinfold thickness (TSFT) were significantly less than reference and control values. Moreover, 20% of patients had MUAC below the 5th percentile (P less than 0.001) and 23% had TSFT more than 2 SD below the mean (P less than 0.001). The discrepancy between these assessments is attributed to the effect of large tumour masses masking diminished true body weight. Children with intra-abdominal solid tumours had significantly lower MUAC and TSFT than those with either extra-abdominal solid tumours or leukaemia, and were more likely to be malnourished based on arm anthropometric criteria. Of all subjects, 44% were consuming less than 80% of their recommended daily allowance of energy at diagnosis, compared with 0% of controls (P = 0.001).

Adolescent

Intestinal malrotation: the role of small intestinal dysmotility in the cause of persistent symptoms.

To investigate the possibility that small intestinal dysmotility is a cause of long-standing and persistent symptoms in patients with malrotation, we retrospectively reviewed 94 patients operated on for intestinal malrotation. In 50 patients operated on during the neonatal period, associated abnormalities were common (24%) and all presented with obstructive symptoms; only three (6%) had continuing mild symptoms the postneonatal period (aged 1 month to 1 year), five of whom (22%) had other abnormalities. Recurrent vomiting was the most common presentation (11/23); only 5 patients (21%) had acute obstruction. Response to operation was good in 18 (78%) and two had persistant symptoms; both died. Twenty-one patients presented beyond infancy (aged greater than 1 year), only 19 of whom had symptoms of less than 2 months' duration. Eight (47%) of those with long-standing symptoms had no relief from operation. Small bowel motility was recorded manometrically in 4 patients with long-standing symptoms. The findings suggest that small intestinal dysmotility may be common in patients with malrotation and persistant symptoms.

Adolescent

Recurrent and persistent diarrhoea in a rural Zimbabwean community: a prospective study.

Prospective surveillance of patterns of diarrhoeal disease was conducted in a cohort of 204 young children living in a rural community in Zimbabwe. Trained field assistants recorded morbidity data obtained by weekly recall of mothers. Diarrhoea was defined by a commonly used local word, and a diarrhoea-free gap of three or more days was taken to signify a new attack. Diarrhoea was common in this study population with a peak incidence between 6 and 18 months of age. There was, however, wide individual variability in diarrhoea attack rates (range 0 to 20 attacks) during the 22 month study period. Whilst only 6 per cent of the recorded diarrhoea episodes were persistent (lasting longer than 14 days), a high proportion (26 per cent) of subjects had at least one attack of persistent diarrhoea (PD) during follow up. Children who had frequent attacks of acute diarrhoea also tended to have PD; PD was rare in those with few attacks. Thus, within this uniformly deprived African community, there were individuals who had a much higher susceptibility to diarrhoea compared to others. An understanding of this variability may point the way towards more effective interventions in the control of diarrhoeal disease.

Child, Preschool

Hypereosinophilic syndrome in childhood appearing as inflammatory bowel disease.

A 7-year-old girl with hypereosinophilic syndrome is described, the first such patient to present with inflammatory bowel disease. Hepatosplenomegaly, anaemia, and hypergammaglobulinaemia were also prominent features. Colonoscopy revealed a frank colitis of nonspecific histologic appearance. An elemental diet was unhelpful, but there was a prompt clinical and partial haematological response to systemic steroids. She has remained well receiving a small maintenance dose of prednisolone for 3 years.

Child