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Zinc protoporphyrin (ZnPP) is a normal metabolite that is formed in trace amounts during heme biosynthesis. The final reaction in the biosynthetic pathway of heme is the chelation of iron with protoporphyrin. During periods of iron insufficiency or impaired iron utilization, zinc becomes an alternative metal substrate for ferrochelatase, leading to increased ZnPP formation. Evidence suggests that this metal substitution is one of the first biochemical responses to iron depletion, causing increased ZnPP to appear in circulating erythrocytes. Because this zinc-for-iron substitution occurs predominantly within the bone marrow, the ZnPP/heme ratio in erythrocytes reflects iron status in the bone marrow. In addition, ZnPP may regulate heme catabolism through competitive inhibition of heme oxygenase, the rate-limiting enzyme in the heme degradation pathway that produces bilirubin and carbon monoxide. Physiological roles, especially relating to carbon monoxide and possibly nitric oxide production, have been suggested for ZnPP. Clinically, ZnPP quantification is valuable as a sensitive and specific tool for evaluating iron nutrition and metabolism. Diagnostic determinations are applicable in a variety of clinical settings, including pediatrics, obstetrics, and blood banking. ZnPP analytical methodologies for clinical studies are discussed. In addition to diagnostic tests and metabolic studies, ZnPP has a potential therapeutic application in controlling bilirubin formation in neonates as a preventive measure for hyperbilirubinemia. Biochemical research techniques, both in vivo and in vitro, are described for further studies into the role of ZnPP in metabolism and physiology.

Objective: Ballard scores are commonly used to estimate gestational age (GA). The purpose of this study was to determine the accuracy of the New Ballard Score (NBS) for infants

Objectives. We assessed the incidence of hyperbilirubinemia, defined as serum total bilirubin ≥15 mg/dL (256 μmol/L), in a cohort of Sephardic Jewish female neonates at risk for glucose-6-phosphate dehydrogenase (G-6-PD) deficiency with especial emphasis on the heterozygotes. We studied the roles of hemolysis by blood carboxyhemoglobin (COHb) determinations and of the variant promoter of the gene for the bilirubin-conjugating enzyme uridine 5′-diphosphate glucuronosyltransferase 1 (UGT1A1) seen in Gilbert's syndrome in the pathogenesis of the hyperbilirubinemia. Methods. Consecutively born, healthy, term, female neonates were screened for G-6-PD deficiency and observed clinically with serum bilirubin evaluations as indicated for hyperbilirubinemia. On day 3, blood was sampled for COHb, total hemoglobin (tHb), and a mandatory serum bilirubin determination. COHb, determined by gas chromatography, was expressed as percentage of tHb and corrected for inspired carbon monoxide (COHbc). DNA was analyzed for the G-6-PD Mediterranean563T mutation and for the variant UGT1A1 gene. Results. The cohort included 54 G-6-PD-deficient heterozygotes, 19 deficient homozygotes, and 112 normal homozygotes. More heterozygotes (12/54, 22%; relative risk: 2.26; 95% CI: 1.07–4.80) and deficient homozygotes (5/19, 26.3%; relative risk: 2.68; 95% CI: 1.05–6.90) developed hyperbilirubinemia, than did normal homozygotes (11/112, 9.8%). Third-day serum bilirubin values that were obtained from 144 neonates were significantly higher in both heterozygotes (11.2 ± 3.7 mg/dL [192 ± 64 μmol/L]) and G-6-PD-deficient homozygotes (12.0 ± 3.0 mg/dL [206 ± 52 μmol/L]) than in the G-6-PD normal homozygotes (9.4 ± 3.4 mg/dL [160 ± 58 μmol/L). In contrast, COHbc values were higher only in G-6-PD-deficient homozygotes (0.74% ± 0.14%) and not in heterozygotes (0.69% ± 0.19%, not statistically significant), compared with control values (0.63% ± 0.19%). High COHbc values were not a prerequisite for the development of hyperbilirubinemia in any of the G-6-PD genotypes. A greater incidence of hyperbilirubinemia was found among the G-6-PD-deficient heterozygotes, who also had the variant UGT1A1 gene, in both heterozygous (6/20, 30%) and homozygous (4/8, 50%) forms, than was found in their counterparts with the normal UGT1A1 gene (2/26, 7.7%). This effect was not seen in the G-6-PD normal homozygote group. A color reduction screening test for G-6-PD deficiency identified only 20.4% (11/54) of the heterozygotes. Conclusions. We showed that G-6-PD-deficient heterozygotes, categorically defined by DNA analysis, are at increased risk for neonatal hyperbilirubinemia. The screening test that was used was unable to detect most heterozygotes. Increased bilirubin production was not crucial to the development of hyperbilirubinemia, but presence of the variant UGT1A1 gene did confer increased risk. bilirubin, carbon monoxide, carboxyhemoglobin, females, gas chromatography, Gilbert's syndrome, glucose-6-phosphate dehydrogenase deficiency, hemolysis, hyperbilirubinemia, neonates, polymerase chain reaction, Sephardic Jews, screening test, uridine 5′-diphosphate glucuronosyltransferase.

Aim—To determine whether increased bilirubin production, reflected by blood carboxyhaemoglobin (COHb) values, is responsible for hyperbilirubinaemia in cases of Down’s syndrome with no obvious cause for excessive jaundice. Methods—Blood was sampled on the third day of life for COHb, total haemoglobin (tHb), and serum total bilirubin, from 19 consecutively born neonates with Down’s syndrome (a subset of 34 term babies), who had developed hyperbilirubinaemia (serum bilirubin> 256 µmol), and from 32 term controls. COHb, measured by gas chromatography, was corrected for inspired CO (COHbc) and expressed as a percentage of tHb. Results—Significantly more of the Down’s syndrome subset developed hyperbilirubinaemia than the controls (10/19 (52%) vs 7/32 (22%), relative risk 2.4, 95% confidence intervals (CI) 1.10 to 5.26). Third day serum bilirubin values (mean (SD)) were higher in the Down’s syndrome neonates than in controls (214 + ‐ 63 µmol/l vs 172 + ‐ 54 µmol/l, respectively, p=0.015). Mean (SD) COHbc values were significantly higher in the Down’s syndrome neonates than in controls (0.92 + ‐ 0.24% vs 0.63 + ‐ 0.17%; p

Background Vitamin A supplementation may reduce the risk of chronic lung disease and sepsis in extremely-low-birth-weight infants. The results of our pilot study suggested that a dose of 5000 IU administered intramuscularly three times per week for four weeks was more effective than the lower doses given in past trials. Methods We performed a multicenter, blinded, randomized trial to assess the effectiveness and safety of this regimen as compared with sham treatment in 807 infants in need of respiratory support 24 hours after birth. The mean birth weight was 770 g in the vitamin A group and 769 g in the control group, and the respective gestational ages were 26.8 and 26.7 weeks. Results By 36 weeks' postmenstrual age, 59 of the 405 infants (15 percent) in the vitamin A group and 55 of the 402 infants (14 percent) in the control group had died. The primary outcome — death or chronic lung disease at 36 weeks' postmenstrual age — occurred in significantly fewer infants in the vitamin A group than in the cont...

Objective.The performance of a point-of-care, noninvasive end tidalbreath carbon monoxide analyzer (CO-Stat™ End Tidal BreathAnalyzer, Natus Medical Inc.) that also reports end tidal carbon dioxide(ETCO2) and respiratory rate (RR), was compared to established,marketed (predicate) devices in children (n = 39) and adults(n = 48) who are normal or at-risk of elevated CO excretion.Methods.Concentrations of end tidal breath CO (ETCO), room air CO,ETCO corrected for inhaled CO (ETCOc), ETCO2, and RR were measuredwith the CO-Stat™ analyzer and the data compared to thoseobtained from the same subjects using the Vitalograph BreathCO monitor(Vitalograph, Inc.) for ETCOc and the Pryon CO2 monitor (SC210 andSC300, Pryon Corp) for ETCO2 and RR. Adults and children werestudied at three medical centers. The data were analyzed by paired t-tests andlinear regression. Bias and imprecision between the CO-Stat analyzer and thepredicate devices was calculated by the method of Bland and Altman.Results.Paired t-tests, performed on the three parametersmeasured with the CO-Stat analyzer and predicate devices showed that only theETCOc values in the adults and the ETCO2 values in the childrenwere significantly different (lower, p ≤ 0.0001, and higher, p≤ 0.0001, respectively). The mean bias and imprecision of the CO-Statanalyzer for adult ETCOc and children ETCO2measurements were−0.9 ± 1.2 ppm and 0.4 ± 0.6%, respectively. Linearregression analysis for the ETCOc results in children and adults had a highdegree of correlation (r= 0.91 and 0.98, respectively).Conclusions.We conclude that in a clinical environment the NatusCO-Stat™ End Tidal Breath Analyzer performs at least as wellas predicate devices for the measurements of ETCOc, ETCO2, and RR.

Medical optical imaging (MOI) uses light emitted into opaque tissues to determine the interior structure. Previous reports detailed a portable time-of-flight and absorbance system emitting pulses of near infrared light into tissues and measuring the emerging light. Using this system, optical images of phantoms, whole rats, and pathologic neonatal brain specimens have been tomographically reconstructed. We have now modified the existing instrumentation into a clinically relevant headband-based system to be used for optical imaging of structure in the neonatal brain at the bedside. Eight medical optical imaging studies in the neonatal intensive care unit were performed in a blinded clinical comparison of optical images with ultrasound, computed tomography, and magnetic resonance imaging. Optical images were interpreted as correct in six of eight cases, with one error attributed to the age of the clot, and one small clot not seen. In addition, one disagreement with ultrasound, not reported as an error, was found to be the result of a mislabeled ultrasound report rather than because of an inaccurate optical scan. Optical scan correlated well with computed tomography and magnetic resonance imaging findings in one patient. We conclude that light-based imaging using a portable time-of-flight system is feasible and represents an important new noninvasive diagnostic technique, with potential for continuous monitoring of critically ill neonates at risk for intraventricular hemorrhage or stroke. Further studies are now underway to further investigate the functional imaging capabilities of this new diagnostic tool.

OBJECTIVES: Our goals were to determine the mortality risk for infants weighing 501 to 1500 gm according to gestational age, birth weight, and gender and to document birth weight-related changes in mortality and morbidity over a 5-year time period. STUDY DESIGN: In this observational study perinatal data were prospectively collected by the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from May 1991 through December 1992 and compared with the corresponding data from 1987 through 1990. Standard definitions were used to record sociodemographic factors, perinatal events, and the neonatal course to 120 days of life, discharge, or death. RESULTS: The 1991 and 1992 cohort included 4279 in-born infants. Among their mothers 10% were < 18 years old; 55% were black, 31% were white, and 11% were Hispanic; 14% had receivedno prenatal care; and 20% had received antenatal corticosteroids. Multiple gestations accounted for 20% of the births. Fifty percent of the infants were delivered by cesarean section. During 1991 and 1992 the overall survival for infants weighing 501 to 1500 gm at birth was 81%, compared with 74% in 1987 and 1988. Survival at birth weight 501 to 750 gm was 44%; it was 81% at 751 to 1000 gm. 92% at 1001 to 1250 gm, and 95% between 1251 and 1500 gm. Female infants had a significantly greater chance of surviving than male infants at similar birth weights and gestational ages. At any given gestational age, smaller infants were less likely to survive. Survival in all birth weight categories increased between 1987 and 1992, without accompanying increases in medical morbidity. Major morbidity increased with decreasing birth weight and included late-onset septicemia 22%, chronic lung disease (oxygen dependence at 36 weeks' corrected age) 18%, severe intraventricular hemorrhage (grades III and IV) 11%, and necrotizing enterocolitis 5%. Twelve percent of all infants were treated with corticosteroids for chronic lung disease, including 36% of infants who were oxygen dependent at age 28 days. The mean length of hospital stay was 69 days for survivors and 18 days for infants who died. CONCLUSIONS: Mortality for infants between 501 and 1500 gm at birth has declined over the past 5 years. There are interactions between birth weight, gestational age, gender, and survival rate. This increase in survival was not accompanied by an increase in medical morbidity.

Most of the carbon monoxide (CO) produced by mammals is a product of the heme oxygenase (HO) reaction, the rate-limiting step in the heme degradation pathway leading to the generation of bilirubin in man. However, some CO is derived from other sources. We studied the association of CO production with lipid peroxidation in tissue preparations from adult male Wistar rats. Supernatants, from 20% tissue homogenates in potassium phosphate buffer, centrifuged for 1 min at 13 000 × g, were incubated for 30 min at 37°C in septum-sealed vials in the dark with ascorbate (100 µM) and Fe(II) (6 µM) and (or) Fe(III) (60 µM). Butylated hydroxytoluene (BHT, 100 µM) was added for the blank reaction. CO produced into the headspace was quantitated by gas chromatography. Thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD), and lipid hydroperoxides (LOOH) in the reaction medium were quantitated by spectrophotometry. Of the tissues studied, CO and TBARS formation was greatest for brain, followed by kidney, lung, spleen, and blood, but no CO or TBARS formation was detected for testes, intestine, liver, and heart. Cell fractionation studies indicated that these differences might be due to the presence of endogenous soluble antioxidants in the latter tissues. Furthermore, these studies demonstrated that CO was exclusively generated by subcellular fractions that contained membranes. The magnitude of the rate of product formation in brain supernatants depended on the concentration of Fe(II) and (or) Fe(III). The formation of CO, TBARS, CD, and LOOH increased linearly with time for up to 30 min, but the rates of product formation were different. Product formation was completely inhibited by BHT (100 µM), biliverdin (50 µM), bilirubin (50 µM), citrate (100 µM), and the Fe(II) chelators, desferrioxamine mesylate (100 µM) and diethylenetriaminepentaacetate, but not by 10 µM of the HO inhibitor, zinc deuteroporphyrin bis glycol. We conclude that CO generation is associated with the process of in vitro lipid peroxidation in tissues with limited antioxidant reserves.Key words: brain, carbon monoxide, conjugated dienes, lipid peroxidation, thiobarbituric acid reactive substances (TBARS).

High intensity light-emitting diodes (LEDs) are being studied as possible light sources for the phototherapy of hyperbilirubinemic neonates. These power-efficient, low heat-producing light sources have the potential to deliver high intensity light of narrow wavelength band in the blue-green portion of the visible light spectrum, which overlaps the absorption spectrum of bilirubin (BR). We compared the efficacy between single LEDs of different color and then constructed a prototype phototherapy device using 300 blue LEDs. The efficacy of this device was compared with that of conventional phototherapy devices by measuring the in vitro photodegradation of BR in human serum albumin. When blue, blue-green, green, and white LEDs were compared, the blue light was the most effective in degrading BR by 28% of dark control, followed by blue-green (18% of control), and then white light (14% of control). Green light was the least effective (11% of control). The prototype device with three focused arrays, each with 100 blue LEDs, generated greater irradiance (> 200 microW.cm-2.nm-1) than any of the conventional devices tested. It also supported the greatest rate of BR photodegradation. We conclude that light from LEDs should be considered a more effective treatment for hyperbilirubinemia than light from presently used phototherapy devices. Furthermore, the unique characteristics of this light source may make it especially suitable for use in safe and lightweight home phototherapy devices.

The Food and Drug Administration recently approved the use of palivizumab (palē-vizhū-mäb), an intramuscularly administered monoclonal antibody preparation. Recommendations for its use are based on a large, randomized study demonstrating a 55% reduction in the risk of hospitalization attributable to respiratory syncytial virus (RSV) infections in high-risk pediatric patients. Infants and children with chronic lung disease (CLD), formerly designated bronchopulmonary dysplasia, as well as prematurely born infants without CLD experienced a reduced number of hospitalizations while receiving palivizumab compared with a placebo. Both palivizumab and respiratory syncytial virus immune globulin intravenous (RSV-IGIV) are available for protecting high-risk children against serious complications from RSV infections. Palivizumab is preferred for most high-risk children because of ease of administration (intramuscular), lack of interference with measles–mumps–rubella vaccine and varicella vaccine, and lack of complications associated with intravenous administration of human immune globulin products. RSV-IGIV, however, provides additional protection against other respiratory viral illnesses and may be preferred for selected high-risk children including those receiving replacement intravenous immune globulin because of underlying immune deficiency or human immuno-deficiency virus infection. For premature infants about to be discharged from hospitals during the RSV season, physicians could consider administering RSV-IGIV for the first month of prophylaxis. Most of the guidelines from the American Academy of Pediatrics for the selection of infants and children to receive RSV-prophylaxis remain unchanged. Palivizumab has been shown to provide benefit for infants who were 32 to 35 weeks of gestation at birth. RSV-IGIV is contraindicated and palivizumab is not recommended for children with cyanotic congenital heart disease. The number of patients with adverse events judged to be related to palivizumab was similar to that of the placebo group (11% vs 10%, respectively); discontinuation of injections for adverse events related to palivizumab was rare.

OBJECTIVE: The study’s aim was to compare outcomes of very low birth weight twins with those of matched singletons. STUDY DESIGN: With data from the Neonatal Research Network registry (May 1991 to December 1994), univariable and multivariable comparisons of very low birth weight twin pairs and singletons were performed in 2 subgroups: (1) all paired twins and singletons with birth weights between 401 and 1500 g and (2) all paired twins and singletons born at RESULTS: Twins constituted 19% of infants admitted with very low birth weight. Mothers of twins were more likely to receive prenatal care, have labor, have cesarean delivery, and receive antenatal glucocorticoids. Twins were more likely to have respiratory disease and to receive surfactant. Second-born twins had more early respiratory disease but similar longer-term outcomes. The risks of death, chronic lung disease, and grade III or IV intracranial hemorrhage were similar in twins and singletons. CONCLUSIONS: Although very low birth weight twins compose a sizable proportion of admissions, in National Institute of Child Health and Human Development Neonatal Research Network intensive care units, twins and singletons have similar outcomes. (Am J Obstet Gynecol 1998;179:742-9.)

Conventional brain-imaging modalities may be limited by high cost, difficulty of bedside use, noncontinuous operation, invasiveness or an inability to obtain measurements of tissue function, such as oxygenation during stroke. Our goal was to develop a bedside clinical device able to generate continuous, noninvasive, tomographic images of the brain using low-power nonionizing optical radiation. We modified an existing stage-based time-of-flight optical tomography system to allow imaging of patients under clinical conditions. First, a stationary head-band consisting of thin, flexible optical fibers was constructed. The headband was then calibrated and tested, including an assessment of fiber lengths, the existing system software was modified to collect headband data and to perform simultaneous collection of data and image reconstruction, and the existing hardware was modified to scan optically using this headband. The headband was tested on resin models and allowed for the generation of tomographic images in vitro; the headband was tested on critically ill infants and allowed for optical tomographic images of the neonatal brain to be obtained in vivo.

The decision to withhold or withdraw life support in the neonatal intensive care unit (NICU) is common but is never routine. Often, moral demands make such decisions difficult and emotionally exhausting. But, what is perhaps more challenging from the moral point of view is the transition from the delivery room to the NICU. A satisfactory analysis of the moral issues of delivery room practices must include a discussion of quality of life, the best interest of the infant, the best interests of the family members, and futile treatment. Although these topics are relevant in any discussion of the moral justification of the omission, withdrawal, or use of treatment for patients, they are especially telling when entertained in the context of the transition of the fetus to a newborn. This article uses these four topics as a moral compass for certain decisions made in the delivery room.

Ventilator-dependent premature infants are often treated with dexamethasone. However, the optimal timing of therapy is unknown.We compared the benefits and hazards of initiating dexamethasone therapy at two weeks of age and at four weeks of age in 371 ventilator-dependent very-low-birth-weight infants (501 to 1500 g) who had respiratory index scores (mean airway pressure x the fraction of inspired oxygen) of 52.4 at two weeks of age. One hundred eighty-two infants received dexamethasone for two weeks followed by placebo for two weeks, and 189 infants received placebo for two weeks followed by either dexamethasone (those with a respiratory-index score ofor =2.4 on treatment day 14) or additional placebo for two weeks. Dexamethasone was given at a dose of 0.25 mg per kilogram of body weight twice daily intravenously or orally for five days, and the dose was then tapered.The median time to ventilator independence was 36 days in the dexamethasone-placebo group and 37 days in the placebo-dexamethasone group. The incidences of chronic lung disease (defined as the need for oxygen supplementation at 36 weeks' postconceptional age) were 66 percent and 67 percent, respectively. Dexamethasone was associated with an increased incidence of nosocomial bacteremia (relative risk, 1.5; 95 percent confidence interval, 1.1 to 2.1) and hyperglycemia (relative risk, 1.9; 95 percent confidence interval, 1.2 to 3.0) in the dexamethasone-placebo group, elevated blood pressure (relative risk, 2.9; 95 percent confidence interval, 1.2 to 6.9) in the placebo-dexamethasone group, and diminished weight gain and head growth (P0.001) in both groups.Treatment of ventilator-dependent premature infants with dexamethasone at two weeks of age is more hazardous and no more beneficial than treatment at four weeks of ages.

Hypoglycemia in the neonate remains a common problem. The association of low blood glucose concentrations and abnormal development has prompted extensive research into the anticipation, evaluation, and treatment of neonatal hypoglycemia. Glucose homeostasis in the fetus and neonate is a developmentally regulated dynamic process involving a number of intricate physiologic mechanisms. In addition, the determination of glucose concentrations is dependent upon both the type of tissue analyzed and the limitations of the specific method employed. The complexity of glucose metabolism makes it difficult to precisely define “normal” and “abnormal” glucose levels in preterm and term neonates.

Jaundice is a common neonatal syndrome. Neonatal hyperbilirubinemia is a complex biologic phenomenon resulting from increased production and limited elimination of bilirubin during the transitional time after birth. Bilirubin production is 2 to 3 times higher in normal term newborns compared with adults, and is greatly exacerbated by hemolysis from any cause, the breakdown of extravascular blood, the shorter red cell life span associated with prematurity, maternal diabetes, cholestasis, unknown factors associated with ethnicity, and many other conditions. Thus, increased bilirubin production is an important contributing cause of all kinds of neonatal jaundice. The ability to predict the degree of jaundice based on the rate of bilirubin production is limited because bilirubin elimination varies greatly from individual to individual in the transitional time after birth. Nonetheless, identifying high producers of bilirubin is important for the diagnosis of hemolysis or the recognition of other risk factors associated with increased bilirubin production. Such risk factors have been identified in the new AAP practice parameter on the management of hyperbilirubinemia in the healthy term neonate1 as important exclusions for a neonate enrolled into the recommended management algorithm. Moreover, information about bilirubin production provides an accurate means of targeting individuals or populations for treatment with heme oxygenase (HO) inhibitors or for assessing the treatment efficacy of a particular HO inhibitor in an individual patient, monitoring directly the mechanism of action of the drug and evaluating dose response. Because carbon monoxide (CO) and biliverdin are produced in equimolar amounts and biliverdin is quantitatively reduced to bilirubin, the measurement of CO in breath or blood can be used as an index of heme degradation and bilirubin production in vivo. The validity of this approach has been well-established.2 The association of increased CO production with kernicterus and death related to hyperbilirubinemia in jaundiced Nigerian infants …

Objective : Inconsistent effects of vitamin A supplementation on prevention of bronchopulmonary dysplasia have been reported. Meta-analysis of these reports resulted in a relative risk of 0.69–1.02 for death or bronchopulmonary dysplasia associated with vitamin A supplementation. Effective dosage regimens or serum retinol concentrations have not been determined in previous reports. The purpose of this pilot study was to define a vitamin A regimen that produces serum retinol concentrations of 25–55 μg/dl. Study design : In this three-phase study, 91 infants (mean birth weight 799–864 g) were enrolled. Vitamin A was administered three times/week for 4 weeks at an average daily dose of 986–2143 IU/day. Physical examinations were performed and serum retinol specimens were collected weekly to assess clinical signs of toxicity. Results : The majority of serum retinol concentrations remained Conclusion : A large clinical trial of vitamin A supplementation with 5000 IU/dose three times/week (25–114% more than the dose used in the three published clinical trials) is needed to assess whether vitamin A supplementation safely reduces the risk of bronchopulmonary dysplasia in very-low-birth-weight infants.

Carbon monoxide (CO) is considered to be a novel neuronal messenger in the brain, similar to nitric oxide. The ontogeny of CO formation in transverse hippocampal slices of the guinea pig was elucidated at selected prenatal and postnatal ages, and the effect of in vitro ethanol exposure on hippocampal CO formation was determined. There was a higher rate of hippocampal CO formation in the fetus at gestational day (GD) 50 and GD 62 (term, about GD 68) compared with the adult. In vitro ethanol exposure (50 and 100 mM) decreased hippocampal CO formation in the GD 62 fetus, which was prevented by incubation with 500 μM l -glutamate.

The objective of the present study was to determine whether whole blood carboxyhemoglobin (COHb) and plasma bilirubin, two indicators of hemolysis, are elevated in infants with severe Rh isoimmune hemolytic disease during the first months of life. Beginning at 2 wk of age and continuing monthly for 3 mo, serial blood samples were obtained for COHb, plasma bilirubin, Hb, reticulocyte count, plasma erythropoietin, plasma enzymes, and plasma iron. Because control infants (n = 13) and infants with ABO hemolytic disease (n = 5) did not differ from one another in any of the study parameters, these two groups were combined and compared with infants with the Rh isoimmunization. Infants with severe Rh isoimmune hemolytic disease (n = 13) were found to have significantly lower Hb and significantly higher bilirubin, the COHb fraction divided by the Hb concentration (COHb/Hb), and plasma erythropoietin levels at 2 and 6 wk of age, and reticulocyte counts at 6 wk. The remaining parameters were not different between the control-ABO group and Rh-isoimmune group at any of the study intervals. The study's two primary indicators of hemolysis, plasma bilirubin and COHb/Hb, were significantly correlated with one another in the Rh-immunized group (r = 0.66, p < 0.0001), but not in the combined control-ABO group. Serial Rh antibody concentrations measured in the serum of four neonates with Rh isoimmunization demonstrated a mean half-life of 14.3 d. We speculate that, among infants with severe Rh isoimmune hemolytic disease, elevated total bilirubin levels and COHb/Hb ratios identified in the early weeks of life indicate continuing hemolysis due to persistence of maternal Rh antibodies.

Several different scoring systems have been developed to predict neonatal morbidity and mortality. In this investigation we compared the utility of four severity of illness scoring systems (SISS) as predictors of days on ventilator (DOV), length of hospital stay (LOS), and mortality in very-low-birth weight (VLBW) premature infants who required mechanical ventilation. The SISS assessed were the Score for Neonatal Acute Physiology (SNAP); the Score for Neonatal Acute Physiology—Perinatal Extension (SNAP+PE); Clinical Risk Index for Babies (CRIB), and the Sinkin Score at 12 hours (SS12). Results revealed significant correlations among the SS12, SNAP, SNAP+PE, CRIB, birth weight (BW), DOV, and LOS. However, none of the systems we assessed offered striking advantage over BW in a VLBW ventilated group.

Heme oxygenase (HO) catalyzes the oxidation of heme to produce carbon monoxide, which is considered to be a novel neuronal messenger in the brain and may play a role in neuronal development. The objective of this study was to determine the effects of in vitro, acute in vivo, and chronic in vivo ethanol exposure on HO activity in the hippocampus, frontal cerebral cortex, and cerebellum of the near-term fetal guinea pig. HO activity was determined using a gas chromatographic method to quantitate CO formation in the microsomal fraction of the homogenate of each selected brain region, incubated with saturating concentrations of heme, NADPH, and O 2 . Fetal body, brain, hippocampal, and cerebellar weights were recorded. In vitro ethanol exposure (25–100 mM) did not affect hippocampal, cerebral cortical, or cerebellar HO activity of the fetal guinea pig at gestational day (GD) 62 (term, about GD 68). Acute maternal oral administration of 4 g ethanol/kg maternal body weight at GD 62 did not affect HO activity in these three fetal brain areas compared with control fetuses (maternal administration of isocaloric sucrose or water). For chronic daily maternal oral administration of 4 g ethanol/kg maternal body weight throughout gestation, fetal body, brain, hippocampal, and cerebellar weights were decreased at GD 62 compared with isocaloric-sucrose/pair-fed and water treatment control groups. Furthermore, isocaloric-sucrose/pair-feeding treatment decreased fetal body and brain weights compared with water treatment. Chronic in vivo ethanol exposure did not alter HO activity in the near-term fetal hippocampus, frontal cerebral cortex, or cerebellum. This is the first study of the effect of ethanol exposure on HO activity in the developing brain of any species. The data demonstrate, for ethanol CNS teratogenesis in the guinea pig manifesting as fetal brain growth restriction, there is no associated change in HO activity in the hippocampus, frontal cerebral cortex, or cerebellum.

1. We have previously shown that carbon monoxide (CO) potently relaxes the lamb ductus arteriosus and have ascribed this response to inhibition of a cytochrome P450-based mono-oxygenase reaction controlling the formation of endothelin-1 (ET-1). In the present study, we have examined whether CO is formed naturally in the vessel. 2. The CO-forming enzyme, haem oxygenase (HO), was identified in ductal tissue in its constitutive (HO-2) and inducible (HO-1) isoforms by Western immunoblotting and immunological staining procedures (both light and electron microscopy). HO-1 was localized to endothelial and muscle cells, while HO-2 was found only in muscle cells. Inside the muscle cells, HO-1 and HO-2 immunoreactivity was limited to the perinuclear region, and the Golgi apparatus in particular. However, upon exposure to endotoxin, HO-1 became more abundant, and both HO isoforms migrated towards the outer region of the cytoplasm close to the sarcolemma. 3. CO was formed enzymatically from added substrate (hemin, 50 microM) in the 10,000 g supernatant of the ductus and its formation was inhibited by zinc protoporphyrin IX (ZnPP, 200 microM). 4. ZnPP (10 microM) had no effect on the tone of the ductus under normal conditions (2.5 to 95% O2), but it contracted the endotoxin-treated ductus (at 2.5% O2). At the same concentration, ZnPP also tended to contract the hypoxic vessel (zero O2). 5. ZnPP (10 microM) curtailed the relaxant response of the oxygen (30%)/indomethacin (2.8 microM)-contracted ductus to bradykinin (35 nM), while it left the sodium nitroprusside (35 nM) relaxation unchanged. 6. We conclude that CO is formed in the ductus and may exert a relaxing influence when its synthesis is upregulated by an appropriate stimulus.

Drugs that displace bilirubin from albumin may increase the risk of kernicterus in neonates. We evaluated the effect of raltegravir on bilirubin-albumin binding in pooled neonatal serum using the peroxidase method. Raltegravir had minimal effect on bilirubin-albumin binding at concentrations of 5 and 10 μM, caused a small but statistically significant increase in unbound bilirubin at 100 μM, and caused potentially harmful increases at 500 and 1000 μM. Our data suggest that the effect of raltegravir on neonatal bilirubin binding is unlikely to be clinically significant at typical peak concentrations reached with usual dosing.

At near-term age the brain undergoes rapid growth and development. Abnormalities identified during this period have been recognized as potential predictors of neurodevelopment in children born preterm. This study used diffusion tensor imaging (DTI) to examine white matter (WM) microstructure in very-low-birth-weight (VLBW) preterm infants to better understand regional WM developmental trajectories at near-term age. DTI scans were analyzed in a cross-sectional sample of 45 VLBW preterm infants (BW≤1500g, GA≤32weeks) within a cohort of 102 neonates admitted to the NICU and recruited to participate prior to standard-of-care MRI, from 2010 to 2011, 66/102 also had DTI. For inclusion in this analysis, 45 infants had DTI, no evidence of brain abnormality on MRI, and were scanned at PMA ≤40weeks (34.7-38.6). White matter microstructure was analyzed in 19 subcortical regions defined by DiffeoMap neonatal brain atlas, using threshold values of trace0.006mm(2)s(-1) and FA0.15. Regional fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated and temporal-spatial trajectories of development were examined in relation to PMA and brain region location. Posterior regions within the corona radiata (CR), corpus callosum (CC), and internal capsule (IC) demonstrated significantly higher mean FA values compared to anterior regions. Posterior regions of the CR and IC demonstrated significantly lower RD values compared to anterior regions. Centrally located projection fibers demonstrated higher mean FA and lower RD values than peripheral regions including the posterior limb of the internal capsule (PLIC), cerebral peduncle, retrolenticular part of the IC, posterior thalamic radiation, and sagittal stratum. Centrally located association fibers of the external capsule had higher FA and lower RD than the more peripherally-located superior longitudinal fasciculus (SLF). A significant relationship between PMA-at-scan and FA, MD, and RD was demonstrated by a majority of regions, the strongest correlations were observed in the anterior limb of the internal capsule, a region undergoing early stages of myelination at near-term age, in which FA increased (r=.433, p=.003) and MD (r=-.545, p=.000) and RD (r=-.540, p=.000) decreased with PMA-at-scan. No correlation with PMA-at-scan was observed in the CC or SLF, regions that myelinate later in infancy. Regional patterns of higher FA and lower RD were observed at this near-term age, suggestive of more advanced microstructural development in posterior compared to anterior regions within the CR, CC, and IC and in central compared to peripheral WM structures. Evidence of region-specific rates of microstructural development was observed. Temporal-spatial patterns of WM microstructure development at near-term age have important implications for interpretation of near-term DTI and for identification of aberrations in typical developmental trajectories that may signal future impairment.

Spots of blood are routinely collected from newborn babies onto filter paper called Guthrie cards and used to screen for metabolic and genetic disorders. The archived dried blood spots are an important and precious resource for genomic research. Whole genome amplification of dried blood spot DNA has been used to provide DNA for genome-wide SNP genotyping. Here we describe a 96 well format procedure to extract DNA from a portion of a dried blood spot that provides sufficient unamplified genomic DNA for genome-wide single nucleotide polymorphism (SNP) genotyping. We show that SNP genotyping of the unamplified DNA is more robust than genotyping amplified dried blood spot DNA, is comparable in cost, and can be done with thousands of samples. This procedure can be used for genome-wide association studies and other large-scale genomic analyses that require robust, high-accuracy genotyping of dried blood spot DNA.

Human preterm birth (PTB) is a complex medical outcome influenced by a combination of genetic and environmental factors. Research on the causative factors of PTB has mostly focused on demographic, socio-behavioral and environmental risk factors. Recent studies turn the spotlight on the effects of heavy metals exposure on adverse pregnancy outcomes. Here we present and evaluate the hypothesis that heavy metals may cause PTB through oxidative stress, and that this effect may be modified by polymorphisms in genes related to oxidative stress. Indeed, accumulating data suggest that the risk of PTB is correlated with polymorphisms in genes involved in detoxification, oxidative stress and lipid metabolism. These and other polymorphisms have independently been associated with susceptibility to the adverse effects of heavy metals.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, a common X-linked enzymopathy can lead to severe hyperbilirubinemia, acute bilirubin encephalopathy and kernicterus in the United States. Neonatal testing for G6PD deficiency is not yet routine and the American Academy of Pediatrics recommends testing only in jaundiced newborns who are receiving phototherapy whose family history, ethnicity, or geographic origin suggest risk for the condition, or for infants whose response to phototherapy is poor. Screening tests for G6PD deficiency are available, are suitable for use in newborns and have been used in birth hospitals. However, US birth hospitals experience is limited and no national consensus has emerged regarding the need for newborn G6PD testing, its effectiveness or the best approach. Our review of current state of G6PD deficiency screening highlights research gaps and informs specific operational challenges to implement universal newborn G6PD testing concurrent to bilirubin screening in the United States.

We sought to identify serological markers capable of diagnosing preeclampsia (PE). We performed serum peptide analysis (liquid chromatography mass spectrometry) of 62 unique samples from 31 PE patients and 31 healthy pregnant controls, with two-thirds used as a training set and the other third as a testing set. Differential serum peptide profiling identified 52 significant serum peptides, and a 19-peptide panel collectively discriminating PE in training sets (n = 21 PE, n = 21 control; specificity = 85.7% and sensitivity = 100%) and testing sets (n = 10 PE, n = 10 control; specificity = 80% and sensitivity = 100%). The panel peptides were derived from 6 different protein precursors: 13 from fibrinogen alpha (FGA), 1 from alpha-1-antitrypsin (A1AT), 1 from apolipoprotein L1 (APO-L1), 1 from inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4), 2 from kininogen-1 (KNG1), and 1 from thymosin beta-4 (TMSB4). We concluded that serum peptides can accurately discriminate active PE. Measurement of a 19-peptide panel could be performed quickly and in a quantitative mass spectrometric platform available in clinical laboratories. This serum peptide panel quantification could provide clinical utility in predicting PE or differential diagnosis of PE from confounding chronic hypertension.

Institutions play an important role in providing an environment in which faculty can thrive such that they are recognized and rewarded for achievements through advancement in rank. While institutions have support systems in place to facilitate promotions, it is ultimately the responsibility of faculty to manage their career trajectory. Therefore, faculty need to understand that part of their academic responsibilities is to invest time and effort in preparing their materials for promotion review. The pathway to the promotion review begins with the hiring decision and continues through the early foundational years of appointment, the milestone of the midterm review, and the subsequent years in which the case for promotion is built and presented for consideration. By the time that the promotion package is submitted, the curriculum vitae, candidate’s statement, sample publications, educator portfolio, and related materials should reflect a record of achievement in satisfaction of promotion criteria. This chapter focuses on institutional and candidate responsibilities regarding the expectations for promotion, long-term planning for the promotion review, and the effective presentation of the promotion package.

Heme oxygenase (HO) is the rate-limiting enzyme in the catabolism of heme to bilirubin. Cobalt chloride (CoCl2) and many other agents that generate oxidant stresses induce the HO-1 isoform. Furthermore, HO-1 has been shown to protect against oxidant stress in vitro and in vivo by mechanisms involving increased ferritin synthesis. However, little is known about the inducibility of hepatic HO-1 during the very early postnatal period, and whether HO-1 induction is associated with increased ferritin synthesis in neonates. Therefore, we studied hepatic HO-1 mRNA, HO-1 protein concentration, total HO activity, and ferritin protein levels in neonatal rats. Neonatal rats 0-5 d of age were injected with 250 μmol/kg body weight of CoCl2 · 6H2O in saline or with an equal volume of saline in age-matched controls. Liver samples were collected 4 h after injection for HO-1 mRNA analysis and 20 h after injection for analysis of HO-1 protein concentration, total HO activity, and ferritin protein levels. In CoCl2-treated rats, hepatic HO-1 mRNA was 3-10 times the levels in control rats (p < 0.05), HO-1 protein concentration was 2-5 times the levels in control rats (p < 0.05), and total HO activity was higher by 20-80% than in control rats (p < 0.05). There were no differences in hepatic ferritin protein levels between CoCl2-treated neonatal rats and controls; however, in CoCl2-treated adult rats, hepatic ferritin protein levels were 1.6 times the levels in controls(p < 0.05). Thus, neonatal rats can up-regulate hepatic HO-1 mRNA. HO-1 protein concentration, and total HO activity in response to CoCl2; however, no up-regulation of hepatic ferritin protein levels was observed in neonatal rats after CoCl2 administration or subsequent HO-1 induction. We speculate that neonatal rats induce hepatic HO-1 and up-regulate ferritin by different mechanisms than do adult rats.

We determined the contribution of haemolysis to the development of hyperbilirubinaemia in glucose-6-phosphate dehydrogenase (G-6-PD) deficient neonates and G-6-PD normal controls. Blood carboxyhaemoglobin (COHb), sampled on the third day of life, was measured by gas chromatography, corrected for inhaled carbon monoxide (COHbC), and expressed as a percentage of total haemoglobin concentration (Hb). Serum bilirubin was tested as clinically necessary. 37 non-jaundiced (peak serum total bilirubin (PSTB)or = 255 mumol/l) and 20 jaundiced (PSTBor = 257 mumol/l) G-6-PD-deficient neonates were compared to 31 non-jaundiced and 24 jaundiced controls with comparable PSTB values, respectively. COHbC values for the entire G-6-PD deficient group were higher than in the controls (0.75 +/- 0.17% v 0.62 +/- 0.19%, P0.001). COHbC and PSTB values did not correlate in the G-6-PD-deficient group (r = 0.15, P0.05) but did in the controls (r = 0.58, P0.001). COHbC values were increased to a similar extent in the G-6-PD-deficient, non-jaundiced (0.72 +/- 0.16%), the G-6-PD-deficient, jaundiced (0.80 +/- 0.19%) and the control, jaundiced (0.75 +/- 0.18%) subgroups, compared to the control, non-jaundiced subgroup (0.53 +/- 0.13%) (P0.05). Although present in G-6-PD deficient neonates, increased haemolysis was not directly related to the PSTB.

Zinc protoporphyrin IX (ZnPP) has been shown to inhibit heme oxygenase (HO) activity effectively in vivo and has potential in the treatment of neonatal jaundice. Because this is a transitional or temporary condition lasting only several days, an effective chemopreventive agent with a relatively short duration of action would be desirable for the treatment of severe neonatal jaundice. To determine the effective duration of action of ZnPP, we administered either 40 nmol/g of body weight ZnPP or 5 microL/g body weight diluent intraperitoneally to neonatal rats 24-36 h after birth. Between 0 and 21 d after ZnPP dosing, the duration of action was investigated through measurements of serum bilirubin and hepatic and splenic HO inhibition, which were correlated to measurements of ZnPP distribution. Significant (p0.05) hepatic HO inhibition, ranging from 27 to 51%, was observed in the liver between 1 and 4 d after dosing, concurrent with a 23-28% reduction in serum bilirubin levels, and was associated with ZnPP tissue concentrations of 27-38 nmol/g. Splenic HO was not inhibited measurably by the much lower concentrations of ZnPP found in the spleen (2.8-20.1 nmol/g) between 0 and 21 d after dosing. Furthermore, HO isoform 1 (HO-1) induction was apparently not a confounding factor in the duration of action of ZnPP, because the modest increases in HO-1 protein levels were not sustained longer than 24 h after ZnPP administration. Our findings demonstrated that the duration of action of ZnPP in neonatal rats is less than 1 wk. The reduction in serum bilirubin levels, the short duration of action and minimal confounding effects suggest that ZnPP may be an effective chemopreventive agent for the treatment of severe neonatal jaundice.

During an 8-month study, 14 laboratories used automated analytical systems to measure total bilirubin concentrations in lyophilized bovine specimens containing 38, 169, and 253 micromol/L bilirubin (2.2, 9.9, and 14.8 mg/dL, respectively). The measured mean +/- SD (n, range) were: 39 +/- 7 micromol/L (n = 90, 31-53) [2.3 +/- 0.4 mg/dL (1.8-3.1)]; 176 +/- 29 micromol/L (n = 89, 146-222) [10.3 +/- 1.7 mg/dL (8.5-13.0)]; and 260 +/- 43 micromol/L (n = 103, 208-316) [15.2 +/- 2.5 mg/dL (12.1-18.5)]. In comparison with target values, measurements were consistently lower at 4, higher at 6, and within +/- 4% at 4 laboratories for each of the three concentrations. The measured values for each concentration remained fairly constant during the study at each laboratory. We conclude that bilirubin measurements differed significantly from the established target values at most of the participating laboratories.

In newborn rabbits, the early cerebral metabolic changes caused by hypoxic-ischemic (H-I) insult was examined by using volume localized 1H-MRS (STEAM). Partial ischemia was caused by unilateral carotid artery ligation, and hypoxia was induced by 10% oxygen inspiration for 150 minutes. Lactate immediately increased after hypoxia induction and almost disappeared 120 to 150 minutes after removal of hypoxia in both H-I and hypoxia-only experiments. Lactate production correlated well with decrease of the blood oxygen saturation. More lactate was produced on ischemic side 50 minutes post-hypoxia induction in H-I study. Ischemia alone did not cause any significant lactate production. Lactate caused by hypoxia can be dynamically monitored by localized 1H-MRS. Existence of regional ischemia can induce greater anaerobic glycolysis and may affect the pattern of brain injury under hypoxia. 1H-MRS is a sensitive tool to detect the acute metabolic changes caused by H-I insult.

Conventional brain imaging modalities are limited in that they image only secondary physical manifestations of brain injury, which may occur well after the actual insult to the brain and represent irreversible structural changes. A real-time continuous bedside monitor that images functional changes in cerebral blood flow or oxygenation might allow for recognition of brain tissue ischemia or hypoxia before the development of irreversible injury. Visible and near infrared light pass through human bone and tissue in small amounts, and the emerging light can be used to form images of the interior structure of the tissue and measure tissue blood flow and oxygen utilization based on light absorbance and scattering. We developed a portable time-of-flight and absorbance system which emits pulses of near infrared light into tissue and measures the transit time of photons through the tissue. Images can then be reconstructed mathematically using either absorbance or scattering information. Pathologic brain specimens from adult sheep and human newborns were studied with this device using rotational optical tomography. Images generated from these optical scans show that neonatal brain injuries such as subependymal and intraventricular hemorrhages can be successfully identified and localized. Resolution of this system appears to be better than 1 cm at a tissue depth of 5 cm, which should be sufficient for imaging some brain lesions as well as for detection of regional changes in cerebral blood flow and oxygenation. We conclude that light-based imaging of cerebral structure and function is feasible and may permit identification of patients with impending brain injury as well as monitoring of the efficacy of intervention. Construction of real-time images of brain structure and function is now underway using a fiber optic headband and nonmechanical rotational scanner allowing comfortable, unintrusive monitoring over extended periods of time.

Synthetic metalloporphyrin derivatives of heme have been identified as competitive inhibitors of heme oxygenase, the rate-limiting enzyme in the heme degradation pathway that produces equimolar quantities of carbon monoxide, biliverdin, and bilirubin. Therefore, administration of metalloporphyrin has been proposed as one means to prevent excessive hyperbilirubinemia in human neonates. Tin proto- and meso-porphyrin have been studied for the suppression of neonatal jaundice. However, these compounds are also photosensitizers. This property may limit the clinical use of these compounds, particularly in infants being exposed simultaneously to phototherapy. Via measurements of carbon monoxide, we have studied the photooxidative, metabolic, and inhibitory characteristics of metalloporphyrins that have not yet been studied for this purpose: deuteroporphyrin bisglycol (DBG), iron deuteroporphyrin bisglycol (FeBG), tin deuteroporphyrin bisglycol (SnBG),tin deuteroporphyrin (SnDP), chromium deuteroporphyrin (CrDP), and zinc deuteroporphyrin (ZnDP). Of the six compounds, SnDP, SnBG, and DBG were significantly photoreactive in vitro. Furthermore, in vitro measurements of brain, liver, and spleen heme oxygenase activity inhibition indicated that, of the nonphotoreactive compounds, CrDP and ZnDP were the most potent inhibitors. Only FeBG served as a substrate for the heme oxygenase reaction. The concentration for 50% inhibition with the three tissues ranged from 0.6 to 1.3 microM for CrDP and from 11.0 to 13.5 microM for ZnDP. When 25 mumol CrDP and 50 mumol ZnDP per kilogram body weight were administered to rats given a heme load of 30 mumol/kg body weight, the total body carbon monoxide excretion due to the administered heme load was reduced by 46 and 32%, respectively, at t = 7.5 h, when the experiment was terminated in order to measure heme oxygenase activity. Brain heme oxygenase activity was not affected by the metalloporphyrin treatment. However, both CrDP and ZnDP inhibited liver tissue heme oxygenase activity to 5 and 20%, respectively, whereas only CrDP inhibited spleen tissue heme oxygenase, to 7% of untreated control. Thus, CrDP appears to be the most attractive of the six compounds and deserves further study.

We evaluated a novel, portable breath sampler/CO-quantifying instrument [Baby's Breath Carbon Monoxide Analyzer (BB); Natus Medical], developed for use at the bedside or with gas samples collected into bags. Bench tests demonstrated that the CO measurements were linear, accurate, and precise when compared with gas chromatography (GC) results. In vivo tests (n = 30) performed with adults showed excellent correlation between end-tidal breath CO measurements (ETCO) corrected for inhaled CO (ETCOc) as determined by BB and GC. Breath sampling efficiency was 96%. ETCOc measurements and blood carboxyhemoglobin fractions (% of total hemoglobin) corrected for inhaled CO (COHbc) correlated strongly: COHbc = 0.25 ETCOc--0.01 microL/L CO (r2 = 0.97, Sy/x = 0.47, SE slope = 0.01, n = 30). The imprecision, assessed by the mean of the population's CV for triplicate determinations, was 11%. Measurements with healthy and hemolytic term newborns showed that ETCOc values of > 3 microL/L correlated with known hemolytic conditions. We conclude that this instrument is clinically reliable and can be used to noninvasively measure ETCO in neonates and adults.

Heme oxygenase (HO) is the first and rate-limiting step in degradation of heme, and in the presence of NADPH-cytochrome P-450 reductase it produces equimolar amounts of biliverdin and CO. CO produced in a closed system can be quantified as described in this unit by gas chromatography as a measure of HO activity in tissue slices, tissue homogenates, and tissue fractions.

The study of pathogenic processes is often limited to ex vivo assays and cell-culture correlates. A greater understanding of infectious diseases would be facilitated by in vivo analyses. Therefore, we have developed a method for detecting bacterial pathogens in a living host and used this method to evaluate disease processes for strains of Salmonella typhimurlum that differ in their virulence for mice. Three strains of Salmonella were marked with bioluminescence through transformation with a plasmid conferring constitutive expression of bacterial luciferase. Detection of photons transmitted through tissues of animals infected with bioluminescent Salmonella allowed localization of the bacteria to specific tissues. In this manner progressive infections were distinguished from those that were persistent or abortive. We observed patterns of bioluminescence that suggested the caecum may play a pivotal role in Salmonella pathogenesis. In vivo efficacy of an antibiotic was monitored using this optical method. This study demonstrates that real time non-invasive analyses of pathogenic events and pharmacological monitoring can be performed in vivo.

Our goals were to determine the mortality risk for infants weighing 501 to 1500 gm according to gestational age, birth weight, and gender and to document birth weight-related changes in mortality and morbidity over a 5-year time period.In this observational study perinatal data were prospectively collected by the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from May 1991 through December 1992 and compared with the corresponding data from 1987 through 1990. Standard definitions were used to record sociodemographic factors, perinatal events, and the neonatal course to 120 days of life, discharge, or death.The 1991 and 1992 cohort included 4279 in-born infants. Among their mothers 10% were18 years old; 55% were black, 31% were white, and 11% were Hispanic; 14% had received no prenatal care; and 20% had received antenatal corticosteroids. Multiple gestations accounted for 20% of the births. Fifty percent of the infants were delivered by cesarean section. During 1991 and 1992 the overall survival for infants weighing 501 to 1500 gm at birth was 81%, compared with 74% in 1987 and 1988. Survival at birth weight 501 to 750 gm was 44%; it was 81% at 751 to 1000 gm, 92% at 1001 to 1250 gm, and 95% between 1251 and 1500 gm. Female infants had a significantly greater chance of surviving than male infants at similar birth weights and gestational ages. At any given gestational age, smaller infants were less likely to survive. Survival in all birth weight categories increased between 1987 and 1992, without accompanying increases in medical morbidity. Major morbidity increased with decreasing birth weight and included late-onset septicemia 22%, chronic lung disease (oxygen dependence at 36 weeks' corrected age) 18%, severe intraventricular hemorrhage (grades III and IV) 11%, and necrotizing enterocolitis 5%. Twelve percent of all infants were treated with corticosteroids for chronic lung disease, including 36% of infants who were oxygen dependent at age 28 days. The mean length of hospital stay was 69 days for survivors and 18 days for infants who died.Mortality for infants between 501 and 1500 gm at birth has declined over the past 5 years. There are interactions between birth weight, gestational age, gender, and survival rate. This increase in survival was not accompanied by an increase in medical morbidity.

The production of bilirubin from heme degradation can be an important cause of neonatal hyperbilirubinemia in a certain subpopulation. Measurements of carbon monoxide production can be used as an index of heme catabolism and bilirubin production. This process can be inhibited by synthetic metalloporphyrin analogs of heme. This review focuses on approaches to identify those neonates who have increased total bilirubin production and to explore some of the new developments in therapeutic modalities.

Rat aorta was homogenized and the 13 000 × g supernatant fraction was tested for heme oxygenase (HO) activity by using a sensitive gas chromatographic method to measure carbon monoxide (CO), one of the products of the HO reaction. The rate of NADPH-dependent CO formation, an index of HO activity, was 1.41 ± 0.40 nmol CO∙mg−1protein∙h−1in the rat aorta supernatant fraction and 2.05 ± 0.55 nmol CO∙mg−1protein∙h−1in the rat liver 13 000 × g supernatant fraction, a tissue known to contain HO activity. Chromium mesoporphyrin (0.05 mM), an inhibitor of rat liver HO, significantly decreased HO activity by 26% in the aorta supernatant fraction and 50% in the liver supernatant fraction. On the basis of the results of this study, which demonstrated HO-catalyzed CO formation in aortic tissue, and previous observations that CO relaxes vascular smooth muscle, we suggest that a physiological role for CO in vascular smooth muscle relaxation should be further investigated.Key words: carbon monoxide, heme oxygenase, vascular smooth muscle, liver, gas chromatographic analysis.

Design and methods. We hypothesized that treatment with recombinant human erythropoietin (r-HuEPO) would stimulate erythropoiesis and would thereby reduce the need for erythrocyte transfusions in preterm infants. We treated 157 preterm infants born at 26.9 ± 1.6 weeks of gestation who weighed 924 ± 183 g at birth with either subcutaneous r-HuEPO (100 U/kg/d, 5 days per week) or placebo for 6 weeks in a randomized, double-blind, controlled clinical trial. All patients received oral iron and were managed according to uniform conservative transfusion guidelines. Results. Treatment with r-HuEPO was associated with fewer erythrocyte transfusions (1.1 ± 1.5 per infant in the r-HuEPO group versus 1.6 ± 1.7 per infant in the placebo group; P = .046) and with a reduction in the volume of packed erythrocytes transfused (16.5 ± 23.0 mL versus 23.9 ± 25.7 mL per infant; P = .023). Overall, 43% of the infants in the r-HuEPO group and 31% of placebo-treated infants were transfusion-free during the study (P = .18). The volume of blood removed for laboratory tests and the need for respiratory support at the start of treatment had major effects on transfusion requirements independent of r-HuEPO. Reticulocyte counts were higher during treatment in the r-HuEPO group (P = .0001), and r-HuEPO-treated infants had higher hematocrit values at the end of the study (32% versus 27.3% in the placebo group; P = .0001). We found no differences in the incidence of major complications of prematurity between the treatment groups. Conclusion. We conclude that treatment with r-HuEPO at a weekly dose of 500 U/kg stimulates erythropoiesis, moderates the course of anemia, is associated with a reduction in erythrocyte transfusions, and appears safe in very low birth weight preterm infants who are receiving iron supplements. Conservative transfusion criteria, minimization of phlebotomy losses, and treatment with r-HuEPO are complementary strategies to reduce erythrocyte transfusions in these infants.