Neonatal respiratory distress: potential for prevention.

A prospective study was conducted of 100 consecutive admissions to the neonatal intensive care unit of the Hospital for Sick Children, Toronto, of infants with respiratory distress syndrome or transient tachypnea of the newborn. It was found that in 15% of cases the illness was completely preventable, being the result of unintentionally premature termination of pregnancy. Significant intrapartum asphyxia occurred in 44% of the infants in whom respiratory distress syndrome developed. Factors placing the pregnancy at high risk were present antenatally in most cases, and most of the deliveries took place in hospitals without adequate facilities or staff, or both, for the requirements of the infant at and following birth.     

Messy eaters: Swabbing prey DNA from the exterior of inconspicuous predators when foraging cannot be observed

Complex coevolutionary relationships among competitors, predators, and prey have shaped taxa diversity, life history strategies, and even the avian migratory patterns we see today. Consequently, accurate documentation of prey selection is often critical for understanding these ecological and evolutionary processes. Conventional diet study methods lack the ability to document the diet of inconspicuous or difficult‐to‐study predators, such as those with large home ranges and those that move vast distances over short amounts of time, leaving gaps in our knowledge of trophic interactions in many systems. Migratory raptors represent one such group of predators where detailed diet studies have been logistically challenging. To address knowledge gaps in the foraging ecology of migrant raptors and provide a broadly applicable tool for the study of enigmatic predators, we developed a minimally invasive method to collect dietary information by swabbing beaks and talons of raptors to collect trace prey DNA. Using previously published COI primers, we were able to isolate and reference gene sequences in an open‐access barcode database to identify prey to species. This method creates a novel avenue to use trace molecular evidence to study prey selection of migrating raptors and will ultimately lead to a better understanding of raptor migration ecology. In addition, this technique has broad applicability and can be used with any wildlife species where even trace amounts of prey debris remain on the exterior of the predator after feeding.     

Transforming NRK cells with avian sarcoma virus reduces the extracellular Ca requirement without affecting the calcicalmodulin requirement for the G1/S transition

NRK rat cells infected with a transformation-defective, temperature-sensitive (ts) mutant of the avian sarcoma virus could not proliferate in Ca²⁺-deficient medium at a nonpermissive temperature (40 °C) that inactivated the viral pp60^v-scr-transforming product and rendered the cells phenotypically untransformed. However, these arrested cells were stimulated to initiate DNA replication with little or no delay while still in the Ca²⁺-deficient medium, either by adding Ca²⁺ or calmodulin at 40 °C or by reducing the temperature to 36 °C which restored the transformed phenotype by rapidly reactivating pp60^v-src. The G1/S transition triggered by restoring the transformed phenotype was suppressed by three different anticalmodulin drugs (R24571, trifluoperazine, W7). The suppression by one of these drugs, trifluoperazine, was overcome by adding calmodulin. Thus, neoplastic transformation by the avian sarcoma virus sharply reduces the extracellular Ca²⁺ requirement for the initiation of DNA replication without bypassing a calcical-modulin-dependent mechanism also needed for the G1/S transition.     

FMRFamide-like Peptides in the Nervous and Endocrine Systems of the Digenean Helminth Echinostoma liei

FMRFamide-like immunoreactivity has been demonstrated in the digenean trematode Echinostoma liei. The functions of FMRFamide-like substances appear to be many and varied within the invertebrates, where they are involved in neurotransmission, cardiovascular regulation, muscular contraction and/or relaxation, and in co-ordination of growth and maturation. It is clearly indicated that FMRFamide-like substances function as neurotransmitter/neuromodulator in E. liei by the abundance of positively stained nerve fibres and perikarya seen throughout the CNS and PNS. A single endocrine-like cell also showing FMRFamide-like immunoreactivity is situated within the muscular cirrus pouch.     

Ruthenium ammine complexes as electron acceptors for growth stimulation by plasma membrane electron transport

Ammineruthenium(III) complexes have been found to act as electron acceptors for the transplasmalemma electron transport system of animal cells. The active complexes hexaammineruthenium(III), pyridine pentaammineruthenium(III), and chloropentaammineruthenium(III) range in redox potential (E ₀) from 305 to –42 mV. These compounds also act as electron acceptors for the NADH dehydrogenase of isolated plasma membranes. Stimulation of HeLa cell growth, in the absence of calf serum, by these compounds provides evidence that growth stimulation by the transplasma membrane electron transport system is not entirely based on reduction and uptake of iron.     

Assimilatory reduction of trimethylamine N-oxide in the yeast Sporopachydermia cereana

Summary Washed microsomal preparations (100 000 xg sediment) from the yeast Sporopachydermia cereana that had been grown on trimethylamine N-oxide as sole nitrogen source catalysed the NAD(P)H-dependent reduction of trimethylamine N-oxide to trimethylamine. Under anaerobic conditions, this was the sole reaction product, but under aerobic conditions only small amounts of trimethylamine accumulated, most being further metabolized to methylamine and formaldehyde (no detectable dimenthylamine accumulated due to its rapid turnover). In the absence of NAD(P)H, no formation of amines or formaldehyde from trimethylamine N-oxide was detected. The trimethylamine N-oxide reductase activity was inhibited by quinacrine, Cu²⁺ ions, triethylamine N-oxide (apparent K _i 0.43 mM) and dimethyl sulphoxide (K _i 0.94 mM). Chlorate and nitrate failed to inhibit the enzyme. The K _m for trimethylamine N-oxide was 29 M. Triethylamine N-oxide was also reduced by the microsomal preparation with the formation of acetaldehyde, and this reduction was sensitive to the same inhibitors as trimethylamine N-oxide, suggesting that both amine oxides are metabolized by the same enzyme(s). It is concluded that trimethylamine N-oxide is metabolized in this yeast via an NAD(P)H-dependent reductase.Abbreviations TMAO triemthylamine N-oxide     

NADH diferric transferrin reductase in liver plasma membrane

Evidence is presented that rat liver plasma membranes contain a distinct NADH diferric transferrin reductase. Three different assay procedures for demonstration of the activity are described. The enzyme activity is highest in isolated plasma membrane, and activity in other internal membranes is one-eighth or less than in plasma membrane. The activity is inhibited by apotransferrin and antitransferrin antibodies. Trypsin treatment of the membranes leads to rapid loss of the transferrin reductase activity as compared with NADH ferricyanide reductase activity. Erythrocyte plasma membranes, which lack transferrin receptors, show no diferric transferrin reductase activity, although NADH ferricyanide reductase is present. The transferrin reductase is inhibited by agents that inhibit diferric transferrin reduction by intact cells and is activated by CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfate) detergent. Inhibitors of mitochondrial electron transport have no effect on the activity. We propose that the NADH diferric transferrin reductase in plasma membranes measures the activity of the enzyme that causes the reduction of diferric transferrin by intact cells. This transmembrane electron transport system requires the transferrin receptor for diferric transferrin reduction. Because the transmembrane electron transport has been shown to stimulate cell growth, the reduction of diferric transferrin at the cell surface may be an important function for diferric transferrin in stimulation of cell growth, in addition to its role in iron transport.     

Viral p21 Ki-RAS protein: a potent intracellular mitogen that stimulates adenylate cyclase activity in early G1 phase of cultured rat cells

Rat kidney (NRK) cells infected with a temperature-sensitive mutant of the Kirsten sarcoma virus were arrested in the G0/G1 phase of their cell cycle by incubation in serum-deficient medium at a p21-inactivating temperature of 41 degrees C. These quiescent ts K-NRK cells were then stimulated to transit G1 and initiate DNA replication by lowering the temperature to 36 degrees C, which rapidly reactivated p21. Reactivating the viral Ki-RAS protein by temperature shift led to an increase in adenylate cyclase activity in early G1 phase. The Ki-RAS protein increased the sensitivity of adenylate cyclase to guanyl nucleotides by a mechanism that seemed to involve inactivation of the enzyme's inhibitory G1 regulatory protein.     

Evidence that the enoyl-CoA hydratase bifunctional protein of mouse liver peroxisomes is identical with the 70,000 dalton peroxisomal membrane protein

Peroxisomal enoyl-CoA hydratase was purified from livers of mice treated with di-(2-ethylhexyl)phthalate and its properties compared with those of the 70 kDa protein present in the membranes prepared by carbonate extraction of peroxisomes. The two proteins had identical subunit molecular masses, of about 70,000 daltons. Limited proteolysis of these proteins using the V8 proteinase of S. aureus yielded identical peptide maps, with these peptides crossreacting with antiserum raised against the 70 kDa membrane protein. These data are consistent with the proposal that the peroxisomal 70 kDa membrane protein and the peroxisomal enoyl-CoA hydratase are the same protein.