Faculty Bibliography

Three widely used screening tests for enteropathy in childhood are the lactose breath hydrogen test, the one-hour serum D-xylose absorption test, and the 72-hour fecal fat determination. To our knowledge, no study has compared these three tests and jejunal biopsy results. A retrospective survey of all jejunal biopsy results at Children's Hospital, Boston, from July 1983 to July 1984 was undertaken to evaluate which test best predicted a normal biopsy result. None of the screening tests was ideal. The lactose breath test had low sensitivity and specificity and did not correlate significantly with biopsy results. The D-xylose and fecal fat tests were each significantly correlated with biopsy results; a normal result of either test was highly predictive of a normal biopsy result. Combining the results of two or more screening tests did not improve predictive value. The xylose test is preferable on the basis of greater sensitivity and ease of patient compliance.

Proteases form stable complexes with alpha 2-macroglobulin (alpha 2-MG) in human plasma. We previously showed that the intestine of newborn rabbits takes up greater amounts of proteases than the intestine of weaned animals, and we suggested that the same phenomenon might occur in the human newborn. To test this possibility, alpha 2-MG complexes were sought in plasma from 3-day-old human infants and adults. In addition, the level of alpha 2-MG was measured. The concentration of alpha 2-MG complexes and of alpha 2-MG was significantly increased in the plasma of infants compared to adults. We suggest that the elevated levels of alpha 2-MG complexes in infants may reflect the enhanced uptake of proteases from the intestine. In addition, there may also be decreased clearance of complexes by the mononuclear phagocytic system in infants. The elevated levels of alpha 2-MG in the infant may reflect a response to the need for neutralizing proteases absorbed from the intestine.

A new method of performing iliopsoas recession in patients with cerebral palsy is described. The approach to the tendon is made by means of a medial incision. The method has been used on seven hips, and the results are comparable to those obtained by a formal anterior approach.

Chromatographic and electrophoretic fractionations of 63Ni-constituents were performed upon renal cytosol samples from rats that were killed following administration of 63NiCl2. At 0.5 to one hr after i.v. injection of 63NiCl2 (0.1 to 0.5 mumole per kg body wt., N = 6), renal cytosol contained 11 percent (SE +/- 2 percent) of the 63Ni-dose. An average of 68 percent (SE +/- 4 percent) of 63Ni in these cytosol samples was associated with low molecular weight components (mol. wt. less than 2,000). The remainder was bound to five macromolecular constituents, with molecular weights of greater than 130,000 (Peak A), approximately 70,000 (Peak B), approximately 55,000 (Peak C), approximately 30,000 (Peak D), and approximately 10,000 (Peak E), based upon column chromatography on Sephadex G-200. The 63Ni that was present in Peaks A to E averaged, respectively, 1.8 percent, 10.7 percent, 7.5 percent, 10.0 percent and 1.6 percent of total 63Ni in renal cytosol. At one to fours hrs after i.m. injection of 63NiCl2 (100 mumol per kg body wt., N = 17), renal cytosol contained 2.2 percent (SE +/- 0.1 percent) of the 63Ni-dose; ultrafiltrable 63Ni averaged 57 percent (SE +/- 3 percent) of total 63Ni in renal cytosol. Macromolecular 63Ni-constituents in these samples were separated by electrophoresis in agarose gel and visualized by autoradiography. Peak D (mol. wt. approximately 30,000) was the most prominent of the five 63Ni-constituents. This study demonstrates that renal cytosol of 63NiCl2-treated rats contains five macromolecular 63Ni-constituents that may be involved in renal uptake, transport, storage, and excretion of 63Ni(II).