Costs and utility of tests in the evaluation of the pediatric patients with syncope.

New diagnostic tests have markedly improved the ability to establish a cause of syncope in pediatric patients, but at a substantial cost. The goal of syncope evaluation should be to diagnose treatable causes and identify patients at high risk for sudden death. The diagnostic utility of commonly used tests is reviewed. Although there are limited data on the application of specific diagnostic tests in the child with syncope, most tests have a low yield in unselected patients. A more directed approach to testing, based on the results of history, physical examination and the electrocardiogram is likely to result in significant cost reduction while still identifying patients with life threatening disorders. Validation of such an approach awaits prospective evaluation.

The omnipotent platelet. Part II: Further observations.

Observation of platelet responses during acute injury or pathology can provide important information. The initial response is thrombocytopenia followed by thrombocytosis. In the case of injury with negative X-ray and appropriate thrombocytosis, a bone scan is indicated. The platelet responds like a sedimentation rate, which indicates the course of the injury or pathology.

The omnipotent platelet.

This information was derived from the increase in platelets of patients following fractures and/or bone surgery and in conjunction with a vast amount of published literature. The increase in numbers of platelets reflects the extent of bone involvement, especially noted in the hip, knee, post-coronary artery bypass graft, and multiple fractures. The role of the platelet in any and all tissues, i.e. soft tissue or bone, whether beneficial or detrimental, is multifunctional. The platelet responds to all physiologic and pathologic states and, if tissue involved is sufficient, the role of the platelet becomes obvious.

Epidemiology of adverse cutaneous reactions to drugs.

Adverse cutaneous reactions to drugs are among the most frequent adverse reactions to many systemically administered therapeutic agents. In addition to these reactions resulting in discontinuation of drugs important to a patient's treatment, some adverse cutaneous reactions to drugs may result in substantial morbidity or even death. The early recognition of these clinically important reactions is made on clinical grounds. Epidemiologic data do suggest, however, that a relatively small number of drugs are responsible most often for these most serious reactions.

Impaired neutrophil function in the cutaneous form of anthrax.

Spontaneous and Bacillus anthracis induced luminol-dependent chemiluminescence of neutrophils was studied in six patients with the cutaneous form of anthrax. Spontaneous chemiluminescence in anthrax was decreased compared to the healthy controls (p < 0.05). B. anthracis, opsonized by complement-containing sera from patients, induced chemiluminescence in neutrophils from control donors but not from patients. B. anthracis, opsonized by complement-free sera from the patients, did not cause an increase in chemiluminescence response in either the patient or the control neutrophils. Also, B. anthracis, opsonized with normal sera and nonopsonized, did not induce chemiluminescence in either patient or control neutrophils. It was concluded that oxidative metabolism by neutrophils is impaired in anthrax, whereas the functional capacity of antibodies seems to be unaffected.

Tryptophan intake influences infants' sleep latency.

Formula-fed infants have depressed plasma tryptophan concentration relative to human milk-fed infants. Because tryptophan alters sleep-waking patterns in adults, a study was designed to determine whether additional dietary tryptophan could elevate plasma tryptophan concentrations of formula-fed infants to concentrations characteristic of human milk feeding and whether differences in plasma tryptophan or the ratio of plama tryptophan to the sum of the other plasma large neutral amino acids (tryptophan:LNAA) were of behavioral significance. Infants were fed a formula (13 g protein/L; whey:casein, 34:66) containing either 0, 294, 588 or 882 mumol/L of added tryptophan. Infants fed human milk or commercial formula (15 g protein/L; whey:casein, 18:82) were included for comparison. In formula-fed groups, plasma tryptophan was directly related to tryptophan intake (r = 0.46, P less than 0.0005). Infants fed commercial formula or the formula without added tryptophan had lower (P less than 0.001) plasma tryptophan compared with infants fed human milk. Only the infants fed the highest tryptophan formula had significantly higher plasma tryptophan:LNAA ratios than the other experimental groups, and these ratios were similar to those of infants fed human milk. The plasma tryptophan:LNAA ratios, not plasma tryptophan concentrations, were predictive of differences in the infants' sleep latency; infants fed formula containing the highest tryptophan had sleep latencies of 18.7 min, significantly shorter (P less than 0.05) than those of infants fed formulas containing less added tryptophan (27.7 min). Feeding infants formulas differing in tryptophan concentration produced differences in sleep latency, which could influence neurobehavioral developments.(ABSTRACT TRUNCATED AT 250 WORDS)