Do small for gestational age infants have less severe neonatal abstinence syndrome?

BACKGROUND: Small for gestational age (SGA) infants are likely to have decreased placental transfer of opioids and other substances and lower amounts of fat deposition, hence less severe neonatal abstinence syndrome (NAS). The goal of this study is to correlate SGA status and severity of NAS in infants admitted to the neonatal intensive care unit (NICU). METHODS: This is a retrospective analysis of term and late-preterm infants (≥35 weeks gestation) exposed to in-utero substances, born between September 2006 and May 2021, and admitted to an inner-city NICU for medical therapy for NAS. Indicators of the severity of NAS (duration of medical treatment, duration of hospitalization, use of phenobarbital, and use of clonidine) were compared between infants characterized as SGA (birth weight <10th percentile for gestational age) to those not categorized as SGA (non-SGA). RESULTS: A total of 992 infants met the study criteria; 205 (20.7%) in the SGA group and 787 (79.3%) in the non-SGA group. The median duration of medical treatment was significantly lower in infants in the SGA group (22 days vs. 26 days, p = 0.04) and they were less likely to be treated with phenobarbital (19% vs. 26.8%, p = 0.02). CONCLUSION: SGA infants displayed less severe NAS symptoms as indicated by shorter a duration of medical treatment and decreased need for phenobarbital. Our findings may impact decisions around identifying the optimum treatment protocols catered to SGA infants with NAS.

Development of an abbreviated symptom score for the neonatal abstinence syndrome.

OBJECTIVE: We sought a shortened MOTHER neonatal abstinence syndrome (NAS) and Finnegan score that would retain comparable performance characteristics of the full instrument. STUDY DESIGN: Retrospective cohort. RESULTS: In total, 124,170 MOTHER NAS scores between August 2007 and May 2016 from 775 infants (≥36 weeks) were examined. Classification and regression tree model identified the most important subsets of the scored variables. A 9-element shortened scale yielded >90% sensitivity and specificity to predict clinical endpoints based on the full 19-element MOTHER NAS score. Conversion of the data sets to the Finnegan score, and applying the same procedure resulted in a nine-element score with similar performance characteristics. CONCLUSION: Shortened scoring instruments were identified with the high-predictive power for clinical endpoints based on the 19-element full MOTHER NAS score. There was no substantial variation in performance for age, supporting the current practice of utilizing a single scoring tool regardless of postnatal age.

Coadministration of theophylline enhances diuretic response to furosemide in infants during extracorporeal membrane oxygenation: a randomized controlled pilot study.

OBJECTIVE: This pilot study evaluates the efficacy of low-dose theophylline administered before furosemide to enhance diuresis in neonates recovering from fluid retention during extracorporeal membrane oxygenation (ECMO). STUDY DESIGN: Infants receiving ECMO (n = 24) were randomized (double blind, placebo-controlled) to receive either regimen A (placebo/furosemide day 1, theophylline/furosemide day 2, placebo/furosemide day 3) or regimen B (theophylline/furosemide day 1, placebo/furosemide day 2, theophylline/furosemide day 3). Urine flows and renal functions were compared. RESULTS: Urine flow rate before initiation of diuretic therapy was not significantly different between groups A and B (2.6 +/- 1.4 vs 3.5 +/- 1.3 ml/kg/hr, respectively, p = 0.12). Infants who received theophylline/furosemide had significantly higher urine flow rates than those who received placebo/furosemide on day 1 (11.8 +/- 4.6 vs 7.2 +/- 2.4 ml/kg/hr, p < 0.01). The 24-hour fluid volumes and balances became significantly more negative with theophylline enhancement of furosemide's effect. There were no significant differences in renal function between the two groups. CONCLUSION: Low doses of theophylline given before furosemide administration significantly enhance diuretic response in infants with fluid retention during ECMO.

Pathway of B1-Alu expression in microinjected oocytes: Xenopus laevis proteins associated with nuclear precursor and processed cytoplasmic RNAs.

We have previously characterized B1-Alu gene expression by microinjected Xenopus laevis oocytes. The transcription, endonucleolytic processing and its kinetics, nuclear transport kinetics, and subsequent cellular compartmentalization have been described previously (Adeniyi-Jones and Zasloff, Nature 317:81-84, 1985). Briefly, a B1-Alu gene is transcribed by RNA polymerase III to a 210-nucleotide (210nt) primary transcript which is processed to yield 135nt and 75nt RNAs. After processing, the 135nt RNA enters the cytoplasmic compartment, where it remains stable, while the 75nt RNA is degraded. In this report we characterize this pathway further and show that the RNAs involved are complexed with specific X. laevis proteins. The primary transcript was associated with an X. laevis protein of 63 kilodaltons (p63) as well as La, a protein known to be associated with RNA polymerase III transcripts. After processing, the cytoplasmic 135nt RNA remained associated only with the X. laevis p63 in the form of a small ribonucleoprotein. Human autoimmune antibodies were purified by affinity chromatography to X. laevis p63 and used to immunoprecipitate human ribonucleoprotein containing a 63-kilodalton polypeptide and small RNAs. These data suggest that Alu-analogous ribonucleoproteins and their metabolic pathways are conserved across species and provide insight as to their possible functions.

Transfer of antibodies directed to paternal major histocompatibility class I antigens from pregnant mice to the developing fetus.

The placental transmission of antibodies directed toward paternal MHC Class I antigens to the developing fetus was studied to assess their effect on the expression of MHC antigens during fetal development and on the development of immune function. 125I-monoclonal anti-paternal MHC antibodies injected i.v. into pregnant mice on day 15 of gestation were efficiently transferred to the fetus within 24 hr in a dose-dependent manner. Biochemical studies on the transferred radioactivity showed that intact antibodies accumulated in the fetus for up to 3 days after antibody injection. During the same period, antibodies were eliminated from the maternal system. The transfer and accumulation of anti-MHC antibodies were independent of the MHC haplotype of the fetus. The pathway of antibody transfer and the localization of transmitted antibodies in the fetus were studied by autoradiographic analysis of the entire fetoplacental unit 24 hr after the injection of anti-paternal MHC antibodies. Our results indicate that antibodies are transferred by way of the placenta and yolk sac, and reach the fetus predominantly via the circulation. Within the embryo proper, the highest levels of antibody were found in the order of blood greater than thymus greater than fetal liver. Most other fetal organs, with the exception of brain and cartilage, showed antibody accumulation, but to a lesser extent. This pattern of antibody distribution over different tissues was similar for allogeneic and syngeneic fetuses. These findings demonstrate that various fetal tissues, including developing lymphoid cells can be directly exposed to the maternally transmitted anti-MHC antibodies, with possible functional consequences on the development of the fetal immune system.

Transcription, processing and nuclear transport of a B1 Alu RNA species complementary to an intron of the murine alpha-fetoprotein gene.

The Alu sequence family comprises the major dispersed repeat sequences of rodent and primate genomes, numbering greater than 300,000 copies in the human haploid genome. The function of these elements is unknown. The sequences can be transcribed by RNA polymerase III and represent a substantial fraction of total heterogeneous nuclear RNA. Alu sequences can be found both in the flanking regions and within the transcription units of several well-characterized genes. Here we show that some members of the mouse B1 Alu sequence family encode a small cytoplasmic RNA. The mouse B1 sequence is congruent to 130 nucleotides long and shows homology with the monomeric units of the dimeric 300-nucleotide primate sequence. By means of microinjection studies in the Xenopus laevis oocyte, we have elucidated a novel pathway leading to the appearance of a processed B1-type Alu RNA species in the cytoplasm. The abundance of this small Alu RNA differs between various mouse tissues, suggesting a role in tissue-specific gene expression.

Generation of long read-through transcripts in vivo and in vitro by deletion of 3' termination and processing sequences in the human tRNAimet gene.

The effects of 3' deletions of the coding and flanking regions of the human tRNAimet gene on its transcription and subsequent processing have been studied both in vitro and in vivo. We demonstrate that in the absence of the oligo T stop signal, polymerase III will read-through efficiently to the next available downstream stop signal. In mutations preserving the 3' terminal sequence of the coding region these read-through transcripts are efficiently processed, irrespective of their length and sequence by an endonucleolytic cleavage to yield both a mature tRNA and an intact trailer RNA. However, deletions involving the terminal regions up to +62 in the coding sequence produce an unprocessed co-transcript of tRNA and downstream sequences. Deletions further within the B promoter box abolish transcription. The use of these mutants as possible "portable" promoters is discussed.

Oxidative decarboxylation of free and peptide-linked amino acids in phagocytizing guinea pig granulocytes.

The oxidative decarboxylation of amino acids by a system consisting of myeloperoxidase-hydrogen peroxide-chloride has been demonstrated previously by others and the process has been considered to be part of the microbicidal armamentarium of some phagocytic leukocytes. We were able to translate these earlier observations, made on model systems, to intact guinea pig granulocytes. We could demonstrate differences in the cellular handling of peptide-linked amino acids as particles, compared with free amino acids. Specific inhibitors were used to explore two routes of oxidative decarboxylation: (a) the myeloperoxidase-catalyzed direct decarboxylation-deamination reaction, and (b) oxidation of alpha-keto acids after transamination of amino acids. These inhibitors were cyanide, azide, and tapazole for the former pathway, and amino-oxyacetate for the latter. Amino-oxyacetate profoundly inhibited the decarboxylation of free 14C-amino acids (alanine and aspartate) in both resting and stimulated cells, but had only a minimal effect on 14CO2 production from ingested insoluble 14C-protein. On the other hand, the peroxidase inhibitors cyanide, azide, and tapazole dramatically inhibited the production of 14CO2 from ingested particulate 14C-protein, but had only small effects on the decarboxylation of free amino acid. Soluble, uniformly labeled 14C-protein was not significantly converted to 14CO2 even in the presence of phagocytizable polystyrene beads. These observation suggest that the amino acids taken up by phagocytosis (e.g., as denatured protein particles) are oxidatively decarboxylated and deaminated in the phagosomes by the myeloperoxidase-hydrogen peroxide-chloride system; soluble free amino acids that enter the cytoplasm by diffusion or transport are oxidatively decarboxylated after transamination by the normal cellular amino acid oxidative pathway.