Exploration of substrate vibrations as communication signals in a webspinner from Ecuador (Embioptera: Clothodidae).

Embiopterans are among the least known of all insect orders, and yet their behavior is worthy of investigation for many reasons. They spin silk produced in glands in their front tarsi and live in groups, usually mothers with their young and sometimes in large colonies with many reproductive females sharing the silk. We discovered a large embiid (Clothodidae) in an Ecuadorian rain forest living under camouflaged silk sheets spun onto the bark of trees. Observations in previous studies of a related Trinidadian clothodid revealed that individuals shake and lunge their bodies in response to intruders of their silk domicile. We took the opportunity afforded by the discovery of the large clothodids to rear them in the laboratory and to investigate their communication behavior. We used piezoelectric film to detect substrate vibrations generated by adult females as elicited by a variety of intruders (an artificial stimulus, conspecific female or male, or a female of different species of webspinners). The residents produced three signals distinguishable by behavioral action, frequency (hertz), pulses per bout, and amplitude at peak frequency. We designated these as lift silk, shake, and snapback. Shakes varied the most in amplitude and frequency in response to the different intruders, and therefore, we propose that shakes may transmit the most information as individuals contact each other. This is the first report to characterize spectral qualities and contexts of substrate vibrations in an embiopteran.

Prevalence of antibodies to Neospora caninum in different canid populations.

A total of 1,554 dogs from 5 countries on 3 continents were tested for antibodies to Neospora caninum using an indirect fluorescent antibody test. In Australia, overall, 42/451 (9%, 95% confidence interval [CI] 6-12%) dogs were seropositive (Melbourne 11/207 [5%, 95% CI 2-9%]; Sydney 18/150 [12%, 95% CI 7-18%]; Perth 13/94 [14%, 95% CI 8-22%]). Antibodies to N. caninum were also detected in dogs in South America (Uruguay [20%, 95% CI 16-24%, n = 414]) and sub-Saharan Africa (Tanzania [22%, 95% CI 12-36%, n = 49]). In contrast, only 1 of 500 dogs tested from the Falkland Islands and none of 140 dogs from Kenya was seropositive. Of wild canids, 1/54 (2%, 95% CI 0-10%) British foxes and 15/169 (9%, 95% CI 5-14%) Australian dingoes had antibodies to N. caninum.

Plasma L-arginine concentrations in premature infants with necrotizing enterocolitis.

OBJECTIVE: To determine whether L-arginine concentrations (the substrate for nitric oxide synthesis) are lower in premature infants in whom necrotizing enterocolitis (NEC) develops than in unaffected infants. METHODS: We measured arginine and nutritional intake, plasma arginine, glutamine, total amino acids, and ammonia concentrations in 53 premature infants (mean gestational age +/- SD: 27 +/- 1.7 weeks) at risk of NEC. Measurements were done on days 3, 7, 14 and 21 and just before treatment in infants with NEC. RESULTS: Necrotizing enterocolitis developed in 11 infants between postnatal days 1 and 26. On day 3, plasma arginine concentrations were decreased compared with normal published values (mean +/- SE, 41 mumol/L +/- 4). Arginine concentrations increased with day of life of measurement (p < 0.001) and arginine intake (p < 0.001). Plasma arginine concentrations were significantly lower at the time of diagnosis in infants with NEC compared with control subjects, even after adjusting for arginine intake and day of life (p = 0.032). Plasma glutamine and total amino acid concentrations were not significantly different in infants with NEC compared with control subjects. Plasma ammonia concentrations were elevated on day 3 (mean +/- SE, 72 +/- 3.3 mumol/L) and decreased with postnatal age (p < 0.001) and increasing plasma arginine concentrations (p < 0.001). CONCLUSION: Plasma arginine concentrations are decreased at the time of diagnosis in premature infants with NEC. The potential benefit of arginine supplementation in the prevention of the disease deserves evaluation.

Double-blind 1-year follow-up of 1540 infants with respiratory distress syndrome randomized to rescue treatment with two doses of synthetic surfactant or air in four clinical trials. American and Canadian Exosurf Neonatal Study Groups.

Synthetic surfactant has been shown to reduce neonatal and 1-year mortality and neonatal morbidity in infants with respiratory distress syndrome. However, less is known about the effects of synthetic surfactant on developmental outcome and long-term morbidity. Four multicenter, randomized, placebo-controlled trials of synthetic surfactant administered as rescue therapy were conducted in the United States and Canada, with a total enrollment of 2224 patients. Double-blind developmental evaluations of survivors were conducted at 1 year of age (adjusted for prematurity) in all four trials. Of the 1802 patients enrolled in the placebo-controlled rescue trials who survived to 1 year, 1540 (85%) completed the 1-year follow-up evaluation. Height, weight, and head circumference measurements were not different in the treatment and control groups. Mean and median Bayley Scores of Infant Development for both the Mental Development Index and the Psychomotor Development Index were also equivalent. The incidence of impairments was not different in the two groups (mild to moderate impairment, 12% (92 of 745) for the air placebo group vs 11% (86 of 771) for the synthetic surfactant group; severe impairment, 15% (114 of 745) for the air placebo group vs 13% (102 of 771) for the synthetic surfactant group). No differences in rates of retinopathy of prematurity or hearing impairment were found in the treatment groups. The need for surgery after day 28 of life (relative risk, 0.779; 95% confidence interval, 0.665, 0.927) and the need for respiratory support at 1 year (relative risk, 0.525; 95% confidence intervals, 0.303, 0.911) were both reduced in the synthetic surfactant group. These results indicate that developmental outcome at 1 year of age is at least as good among infants with respiratory distress syndrome who received rescue therapy with synthetic surfactant as it is in infants who received air placebo; the results also indicate that the incidence of long-term morbidity is reduced.

Effects of two rescue doses of synthetic surfactant in 344 infants with respiratory distress syndrome weighing 750 to 1249 grams: a double-blind, placebo-controlled multicenter Canadian trial. Canadian Exosurf Neonatal Study Group.

In a multicenter, double-blind, placebo-controlled rescue trial conducted at 13 Canadian hospitals, two 5 ml/kg doses of a synthetic surfactant or air placebo were administered to 344 infants with birth weights of 750 to 1249 gm who had established respiratory distress syndrome and an arterial/alveolar oxygen tension ratio less than 0.22. The first dose was given between 2 and 24 hours of age, and the second dose was given 12 hours later to the infants remaining on mechanical ventilation. Infants were stratified at study entry by birth weight and gender. The trial was terminated short of the targeted sample size because significant reductions in mortality were observed in another rescue trial completed in the United States in the same weight class of infants. Despite premature termination of the trial, the rate of survival without bronchopulmonary dysplasia was increased (61% vs 52%; p = 0.046) in infants treated with surfactant. In addition, there was a significant reduction in the incidence of overall pulmonary air leak (46% vs 32%; p = 0.009), pneumothorax (27% vs 17%; p = 0.023), and pulmonary interstitial emphysema (40% vs 28%; p = 0.018) in infants treated with synthetic surfactant. There was no difference in the incidence of bronchopulmonary dysplasia, apnea, or pulmonary hemorrhage. Significant improvements in alveolar-arterial oxygen tension gradient, arterial/alveolar oxygen tension ratio, and oxygen and ventilator requirements through day 7 were present. These findings indicate that rescue therapy with synthetic surfactant can improve outcome for premature infants weighing 750 to 1249 gm with respiratory distress syndrome.

Retrospective search for bleeding diathesis among premature newborn infants with pulmonary hemorrhage after synthetic surfactant treatment. The American Exosurf Neonatal Study Group I, and the Canadian Exosurf Neonatal Study Group.

In an across study analysis of five multicenter, placebo-controlled trials of the synthetic surfactant, Exosurf Neonatal, involving infants with birth weights 700 gm or greater the incidence of clinical pulmonary hemorrhage was 1.9% in treated infants and 1.0% in control infants. To determine whether this apparent increase in pulmonary hemorrhage was the result of a bleeding diathesis, we retrospectively reviewed charts for 39 of 41 infants with clinical pulmonary hemorrhage. The incidence of nonpulmonary bleeding was the same in control- and surfactant-treated infants. Platelet counts, hematocrit values, and the number of transfusions with platelets or red blood cells did not differ between the two groups. There was no evidence that surfactant treatment was specifically associated with a generalized bleeding diathesis.