Linking breeding and wintering ranges of a migratory songbird using stable isotopes.

We used the natural abundance of stable isotopes (carbon and hydrogen) in the feathers of a neotropical migrant songbird to determine where birds from particular breeding areas spend the winter and the extent to which breeding populations mix in winter quarters. We show that most birds wintering on western Caribbean islands come from the northern portion of the species' North American breeding range, whereas those on more easterly islands are primarily from southern breeding areas. Although segregated by breeding latitude, birds within local wintering areas derive from a wide range of breeding longitudes, indicating considerable population mixing with respect to breeding longitude. These results are useful for assessing the effects of wintering habitat loss on breeding population abundances and for predicting whether the demographic consequences will be concentrated or diffuse.

Reversal of protein-losing enteropathy with heparin therapy in three patients with univentricular hearts and Fontan palliation.

We studied three pediatric patients with protein-losing enteropathy in conjunction with univentricular hearts and right atrial to pulmonary artery anastomosis (Fontan operation) before and during heparin therapy. Each patient showed dramatic improvements in symptoms, marked elevations in serum albumin levels, and quantitative reversal of enteric protein loss within a few weeks of beginning therapy. These findings suggest that heparin may be an important treatment for this poorly understood condition.

LSD flashback syndrome exacerbated by selective serotonin reuptake inhibitor antidepressants in adolescents.

Two adolescents with a long history of abuse of lysergic acid diethylamide (LSD) and symptoms consistent with major depressive disorder, on initiation of antidepressant therapy with selective serotonin reuptake inhibitor agents, had the new onset or worsening of LSD flashback syndrome. The similarity in neuroreceptor physiology for both LSD and serotonin suggests that the LSD flashback syndrome may be induced by these drugs in patients with a history of LSD abuse.

Immunoglobulin secretion by the normal and the infected newborn infant.

The development of quantitative single-cell immunoassays has provided a novel opportunity to demonstrate the isotype-specific immunoglobulin responses in normal and infected neonates. The reverse enzyme-linked immunospot assay was used to determine the number of immunoglobulin-secreting cells (IgSCs) in peripheral blood. Baseline numbers of IgSCs were established in 69 uninfected term and preterm infants within 5 days of birth; values above the 99th percentile were considered elevated. The IgSCs were also measured in 266 infants with proved or suspected infections or congenital anomalies. A subset of newborn infants was retested weekly. Few IgSCs (mostly IgMSCs) were detected within 5 days of birth in uninfected neonates, but by 1 month 77% had increased numbers of IgSCs, primarily IgASCs. Sixty-three (24%) of 266 study infants had increased IgSCs on initial sampling (predominantly IgMSCs); these included infants as immature as 25 to 27 weeks of gestational age; elevations in IgSCs were most frequent in infants with intrauterine infections. Increased numbers of IgSCs were uncommon in infants with early-onset sepsis in the first 5 days but were frequent by the second week, consistent with acquisition of infection near the time of delivery. We conclude that the presence of elevated numbers of IgSCs soon after birth may be a useful surrogate marker of untreated intrauterine infection. The development of predominantly IgASCs in the first month of life suggests postnatal exposure to common mucosal antigens.