Proliferation to paucity: evolution of bile duct abnormalities in a case of Alagille syndrome.

Alagille syndrome is an autosomal dominant disorder characterized by abnormalities in multiple organ systems, including the liver, and is caused by mutations in JAG1. Chronic cholestasis secondary to paucity of interlobular bile ducts is traditionally both a clinical and a pathologic hallmark of this disease at diagnosis. We describe the biliary changes on serial liver biopsies in a patient who presented with jaundice and extrahepatic stigmata of Alagille syndrome. Her initial specimens at 6 and 10 months of age demonstrated interlobular bile duct proliferation and cholestasis, suggestive of distal biliary obstruction. A specimen at 2 years of age showed near-total absence of interlobular bile ducts, with the classic histologic appearance of bile duct paucity. We present this case to underscore the potential pitfalls in interpreting cholestatic liver morphology in the absence of clinical information. The progression of bile duct abnormalities is discussed in the context of the role postulated for JAG1 in postnatal liver growth and development.

Effect of carbohydrates on calcium absorption in premature infants.

Premature infants are susceptible to disease related to deficient dietary calcium intake. Studies in adults suggest carbohydrates can enhance calcium absorption. However, little is known about how carbohydrates affect calcium absorption in premature infants due to a lack of direct in vivo studies. We adapted the triple lumen perfusion method for use in premature infants to compare calcium absorption 36 mmol/L (1.44 g/L) in the absence and presence of either 70 g/L lactose or glucose polymers. 44Ca was added to determine endogenous calcium losses. Fourteen infants were studied (gestational age: 31 +/- 0.4 wk; study weight: 1590 +/- 105 g; mean +/- SEM). Calcium absorption from the glucose polymer solution was greater than that from the control and lactose solutions (0.17 +/- 0.05 mumol.min-1.cm-1 versus 0.04 +/- 0.04 and 0.008 +/- 0.045 mumol.min-1.cm-1, respectively). Calcium absorption correlated positively with water and carbohydrate absorption. The rate of carbohydrate absorption was greater from the glucose polymers than from the lactose solution (0.40 +/- 0.10 mg.min-1.cm-1 versus 0.22 +/- 0.06, respectively). Based upon 44Ca absorption, endogenous calcium loss appeared to account for less than 1% of total calcium flux. We conclude that glucose polymers, but not lactose, enhance calcium absorption in the premature infant, a fact that may be useful in formula design.

Bolus versus continuous feedings stimulate small-intestinal growth and development in the newborn pig.

Although bolus and continuous tube feedings are common, little is known about their effect on the developing small intestine. To compare their effect on small-intestinal growth and differentiation, six pairs of 3-day-old piglet littermates were randomized to receive similar volumes of sow milk replacer, either by bolus (four times daily, group B) or continuous feedings (over 24 h, group C) for 7 days. The piglets were then killed and small-intestinal length, weight, protein mass, and disaccharidase activities were determined. Small-intestinal mucosal weight and ileal protein mass were greater in group B than in group C (p = 0.0024 and 0.019, respectively). No differences were noted between groups in jejunal mucosal protein mass. Ileal maltase activity also was greater in group B than group C (p = 0.02). Although ileal lactase activity in group B was twice that in group C, the differences did not quite reach statistical significance (p = 0.11). No differences between groups were noted in ileal or jejunal sucrase activity. Our study demonstrated that bolus feedings increased mucosal mass, protein mass, and maltase activity to a greater degree than continuous feedings. These results may have clinical significance for infants receiving long-term tube feedings.

Treatment of infants with acute diarrhea: what's recommended and what's practiced.

In 1985, the American Academy of Pediatrics (AAP) published a policy statement on the treatment of infants with acute diarrhea complicated by mild to moderate dehydration. To determine how closely physicians in the United States follow the AAP's treatment guidelines, a questionnaire was sent to 457 pediatricians and 360 family practitioners. The questionnaire presented a hypothetical infant with acute diarrhea complicated by mild to moderate dehydration and included questions regarding the number of such patients seen yearly, length of time used to rehydrate the infant, and how formula or solids are introduced following rehydration. Complete responses were received from 53% of pediatricians and 40% of family practitioners. The number of patients with acute diarrhea seen per year did not affect physician's treatment. Pediatricians and family practitioners responded similarly to most questions. Contrary to the AAP's guidelines to rehydrate in 4 to 6 hours, 62% of responding physicians extend the rehydration period to 12 to 24 hours. Also contrary to the AAP's recommendations, 62% of pediatricians and family practitioners use a lactose-free formula. The majority of responding physicians do follow the AAP's treatment guidelines to initiate feedings with diluted formula. Significantly more pediatricians than family practitioners advance to a full-strength formula within 1 day (P = .011). Fewer than 50% of physicians polled started solids within 24 hours as suggested by the AAP. Overall, the findings suggest that very few pediatricians and family practitioners follow all aspects of the AAP's treatment guidelines for infants with acute diarrhea complicated by mild to moderate dehydration.