Breastfeeding, dehydration, and shorter maternity stays.

Over a five-month period eight breastfed infants required readmission to Wesley Long Community Hospital in Greensboro, North Carolina, within 48 hours of discharge from the newborn nursery. The primary diagnoses upon readmission included hyperbilirubinemia and suspected sepsis. At discharge from the intensive care nursery, mild dehydration secondary to inadequate breastfeeding was deemed a significant factor in precipitating the need for readmission. This increase in readmissions represented a significant change from the past year. An intensive review of each initial hospital stay was conducted to attempt to identify causative factors and to develop a profile of infants who might be at risk for readmission in the future.

Cold stress influence on lung lecithin in the newborn rabbit.

Term, food-water deprived newborn rabbits exposed to a cold environment for 48 h demonstrated a significant decrease in total lung lipid (p less than 0.01), total triglyceride (p less than 0.001), total phospholipid (p less than 0.05), and total phosphatidylcholine (p less than 0.025). Disaturated phosphatidylcholine remained unchanged. Fatty acid methyl esters of total and disaturated phosphatidylcholine were not influenced by cold stress. Likewise, there was no alteration in pulmonary function as determined by deflation pressure-volume relationships.

Gastric response in low birth weight infants fed various formulas.

Feeding techniques, delayed gastric emptying, volume overload, or reverse peristalsis may lead to regurgitation and aspiration in the premature infant. Noting these complications, various aspects of gastric function were studied in relation to the type of formula fed. 27 low birth weight infants (less than 2,000 g) were each fed one of three randomly assigned commercial formulas, which varied in osmolarity and MCT content. Gastric pH and emptying were monitored during the first 48 h of life. The fatty acid chain length of the triglyceride in the formula apparently did not influence either gastric pH or emptying. Infants fed formulas having a higher osmolar load (539 mosm/1) and containing protein hydrolysate showed greater gastric retention.

Riboflaven and bilirubin response during phototherapy.

Twenty-four jaundiced neonates were studied, 12 in the treatment group and 12 in the untreated group. Patients were randomly selected to receive oral riboflavin. The mean 24-hr bilirubin decrease was determined during phototherapy. Blue light (420-470 nm) energy ranged from 6-10 muW/cm2. The observed 24-hr bilirubin decreased was compared with the expected decrease based on an energy-dose-response relationship. Riboflavin-treated infants received either 6-7 mu W/cm blue light energy or 810 muW/cm (same as control group). Those infants receiving less energy than the control group (8-10 muW)cm2 had a mean 24-hr bilirubin decrease (3.05 mg/100 ml/24 hr) equal to the control group (3.09 mg/100 ml/24 hr). Those riboflavin-treated infants receiving energy equal to the control group showed a greater decline (5.2 mg/100 ml/24 hr) in their mean 24-hr bilirubin. Although effective, additional in vivo studies are required to clarify the full effects, especially on DNA, of using photosensitizers such as riboflavin in the presence of bilirubin and blue light energy (420-470 nm).

T7 RNA polymerase: conformation, functional groups, and promotor binding.

Circular dichroic spectra of T7 RNA polymerase show minima at 222 nm ([theta]m=-7.9 X 10(3) deg cm2/dmol) and 208 nm ([theta]m =-7.55 X 10(3) deg cm2/dmol) and a maximum at 193 nm ([theta]m = 1.2 X 10(4) deg cm2/dmol). The small mean residue ellipticity above 200 nm indicates that the secondary structure contains approximately 12% alpha helix. The secondary structure is unaltered by high salt, glycerol, -SH reagents, nitration of tyrosyl residues, and chelating agents. Binding of the native enzyme to [32P]T7 DNA has been measured by the retention of the protein-[32P]DNA complexes on nitrocellulose filters. At 37degrees T7 RNA polymerase binds to its promoters in the absence of NTP's. Binding and catalytic activity are both abolished at 0degree. Binding of the initiating [gamma-32P]GTP can also be detected by the filter binding assay. Native T7 RNA polymerase is inactivated by reaction with 1 mol of 5,5'-dithiobis(2-nitrobenzoic acid) (Nbs2) or 1 mol of [14C]iodoacetamide. The latter reaction is blocked by Nbs2 suggesting that a single -SH group is required for activity. Alkylation of the -SH group does not alter binding of the enzyme to the DNA template, but modifies the binding of GTP to the enzyme. Nitration of approximately4 surface tyrosyl residues of the protein prevents binding to T7 DNA. The restriction endonuclease, Hpa II, cuts T7 DNA into approximately40 fragments and reduces total RNA synthesis by T7 RNA polymerase by 70%. Fragmentation of the DNA template by Hpa II does not alter the rate of RNA chain initiation by T7 polymerase, and restriction fragments accounting for approximately25% of the T7 DNA still bind tightly to the enzyme. Thus the T7 RNA polymerase promoters remain intact on the restriction fragments. Gel electrophoresis of the transcription products, using restriction fragments as templates, show that of the seven in vitro transcripts produced by T7 RNA polymerase from whole T7 DNA, only the smallest (representing the last 1.5% of the genome) is transcribed from Hpa II fragments. The remaining transcripts are replaced by six new and much shorter mRNA's. The DNA fragments containing the promoters for these mRNA's have been removed from the fragment mix by binding them to the enzyme and retaining the complexes on nitrocellulose filters.