Search

A large number of studies in recent years have described protein and nitrogen metabolism in the neonate. However, the majority of these data are difficult to interpret because of a number of confounding variables, particularly in very low birth weight (VLBW) infants. In contrast, application of state-of-the-art tracer isotopic and molecular biology methods in isolated cell system and whole animals has resulted in major advances in our understanding of the regulation of protein breakdown, synthesis, and protein accretion. The following workshop summary reviews the recent developments in basic physiology of protein metabolism in cellular and animal models in relation to human preterm infants, and identifies the important areas toward which future basic and clinical research should be directed to provide for optimal nitrogen accretion and growth of the VLBW infant.

Background: Septicemia is a major antecedent of morbidity and mortality in very low birth weight (501- to 1500-g) infants. Our purpose was to determine prospectively the incidence, clinical presentation, laboratory features, risk factors, morbidity and mortality associated with late onset septicemia in infants 501 to 1500 g., Methods: Clinical data were prospectively collected for 2416 infants enrolled in a multicenter trial to determine the efficacy of intravenous immunoglobulin in preventing nosocomial infections. Septicemia was confirmed by positive blood culture in 395 symptomatic infants. Multivariate analyses of factors associated with septicemia were performed., Results: Sixteen percent of VLBW infants developed septicemia at a median age of 17 days. Factors associated with septicemia by logistic regression included male gender, lower gestational age and birth weight and decreased baseline serum IgG concentrations. Increasing apnea (55%), feeding intolerance, abdominal distension or guaiac-positive stools (43%), increased respiratory support (29%), lethargy and hypotonia (23%) were the dominant presenting features of septicemia. An abnormal white blood cell count (46%), unexplained metabolic acidosis (11%) and hyperglycemia (10%) were the most common laboratory indicators. Septicemic infants, compared with nonsepticemic infants, had significantly increased mortality (21% vs. 9%), longer hospital stay (98 vs. 58 days) and more serious morbidity, including severe intraventricular hemorrhage, bronchopulmonary dysplasia and increased ventilator days (P < 0.001)., Conclusions: Late onset septicemia is common in very low birth weight infants, and the rate is inversely proportional to gestational age and birth weight. Septicemia is more common in males and those with low initial serum IgG values. A set of clinical signs (apnea, bradycardia, etc.) and laboratory values (leukocytosis, immature white blood cells and neutropenia) increase the probability of late onset sepsis, but they have poor positive predictive value.

Protein-calorie malnutrition in experimental animals resulted in a complex picture of changes in various drug-metabolic pathways. The need for these studies is discussed in the context that undernutrition is prevalent in many countries and coincides with many intercurrent illnesses in the affected populations. The need of these affected populations for appropriate therapies is recognized, and these therapies should be based on scientific principles rather than on empiricism.

The use of drugs during pregnancy is very common; some substances can provoke in the foetus troubles and anatomical or functional disorders which may be detected either at birth or later on. Then it is necessary the physicians restrict the prescription of therapeutical agents for and only for well-knowned indications. The education of people in regard of this subject is also necessary about drugs used during pregnancy without medical advices.

Mechanisms of transport of environmental pollutants and ingested drugs in breast milk and their absorption in newborn nurslings are outlined. The authors urgently call for additional research to determine which maternal medications are safe for nursing infants.

Epidemiologic studies have provided much of the knowledge concerning adverse side effects of exposure to drugs and other xenobiotics transmitted via breast milk. Adverse effects can be immediate and usually recognizable or long-term and difficult to define. Acute effects may be due to individual idiosyncrasy, allergic reaction, or manifestation of acute toxicity. We need further human clinical investigations to determine actual dosing to nursing infants and to ascertain the existence of subtle and presently unrecognized long-term effects.

A workshop, held in May, 1978, at the National Institute of Child Health and Human Development, considered the quality control of reagents and assays for measuring alpha fetoprotein (AFP) in maternal serum and amniotic fluid for the antenatal screening and diagnosis of open neural tube defects. The recommendations, published in detail elsewhere and summarized in this article, were based on what was known to be readily achievable and on estimates of the effect of assay performance on screening and diagnostic sensitivity and specificity. Main points considered included: (1) choice of units for AFP measurement and interpretation, (2) need for National AFP Reference Preparations and the need for a scientific panel to assess the adequacy of these reference materials, (3) information needed from reagent manufacturers, (4) criteria for assay performance, (5) biological sources of reagents, (6) need for laboratory and epidemiologic monitoring, and (7) need for a minimum assay workload.

Protein deficiency in post-suckling rats produced changes in the activity of hepatic drug-metabolizing enzymes. Significant decreases occurred in the N-demethylation of aminopyrine, in the azo-reduction of neoprontosil and in sulfokinase activity (using p-nitrophenylsulfate as SO4 donor). An increase was recorded for the glucuronidation of p-nitrophenol and no changes were noted in the hydroxylations of hexobarbital and aniline. Refeeding the animals for 3 weeks returned all activities to control values. An exception was the azo-reductase activity indicating either a slower recovery or a permanent change.