Intraosseous infusion of resuscitative fluids and drugs: long-term effect on linear bone growth in pigs.

We studied the effects of intraosseous (IO) infusion of a standard fluid bolus and resuscitative drugs on long-term bone growth and epiphyseal closure in the "pediatric" swine model. Eighteen weanling pigs were randomly assigned to six groups as follows: three animals received two normal saline boluses, 20 mL/kg IO over 20 minutes; three received sodium bicarbonate, 1 mEq/kg IO; three received a 10% sodium bicarbonate infusion IO at maintenance rate over 1 hour; three received epinephrine 1:10,000, 0.1 mL/kg IO; three received an epinephrine infusion IO at 1 microgram/kg/min for 1 hour; and three received a dopamine infusion IO at 10 micrograms/kg/min for 1 hour. All infusions were given in the left hindleg; the right hindleg was used as a control. Lateral radiographs of the hind extremities were obtained at the beginning of the study and at 1 and 3 months after infusion. Linear radiographic measurements of the infused and control tibias were compared. At 6 months after infusion, the tibias were harvested, measured directly, and radiographed to determine the degree of epiphyseal closure. Analysis of variance for the first 3 months' data yielded a nonsignificant time-by-treatment interaction (P = .84) and a nonsignificant main effect for time (P = .22). Separate analysis of the direct measurements taken at 6 months revealed no difference in growth between experimental and control tibias. In addition, no radiographic difference in epiphyseal closure was noted between the two groups at the conclusion of the study, nor were any structural defects discovered. Intraosseous infusion of fluids and resuscitative drugs does not adversely affect subsequent bone growth and development in the swine model.     

An electrophysiological investigation of the relationship between conceptual fluency and familiarity

Brain potentials associated with the manipulation of conceptual fluency in a recognition memory paradigm were recorded. Enhanced fluency was associated with attenuation of the N400 and an increased rate of subjects' endorsing both studied and non-studied items as having been studied ("old" responses) in the recognition test. Differences were also found in latencies previously associated with post-retrieval processing, such that in the setting of enhanced fluency (1) non-studied items were associated with a positive wave from 800 to 1600 ms and (2) items endorsed as "new" were more positive than those endorsed as "old" from 1200 to 1600 ms. The effects on the N400 may be related to the impact of fluency on familiarity, whereas later processing may be involved in the attribution of fluency to prior experience.     

Diagnosis of pneumococcal pneumonia by psaA PCR analysis of lung aspirates from adult patients in Kenya

psaA is the gene encoding pneumococcal surface adhesin A (PsaA), a 37-kDa protein expressed on the surface of Streptococcus pneumoniae. PCR primers for psaA have been shown to amplify the target DNA sequence in all 90 serotypes of S. pneumoniae and in none of 67 heterologous pathogens and colonizing bacteria of the upper respiratory tract. Pathogenic bacteria identified in lung aspirate specimens cannot normally be dismissed as contaminants or colonizers, which limit the assay specificity of other respiratory tract specimens. psaA PCR analysis was evaluated in 171 lung aspirates from Kenyan adults with acute pneumonia. The limit of detection was one genome equivalent. Sensitivity, estimated in 35 culture-positive lung aspirates, was 0.83 (95% confidence interval, 0.70 to 0.95). psaA PCR analysis extended the number of identifications of S. pneumoniae in lung aspirates from 35 on culture to 61 by both methods. Of 26 new pneumococcal diagnoses, 19 were corroborated by results of blood culture or urine antigen detection. Sequences of the PCR products from 12 positive samples were identical to the psaA target gene fragment. Using an internal control for the PCR, inhibition of psaA PCR was demonstrated in 17% (8 of 47) of false-negative specimens. The results of a control PCR for the human gene beta-actin suggested that false-negative psaA PCR results are attributable to problems of specimen collection, processing, or DNA extraction in 30% of cases (14 of 47). psaA PCR analysis is a sensitive tool for diagnosis of pneumococcal pneumonia in adults.     

Neutrophil-rich Ki-1-positive anaplastic large cell lymphoma: a study by fine-needle aspiration biopsy

Fine-needle aspiration biopsy (FNAB) is an accurate, cost-effective method of evaluating lymphomas. The neutrophil-rich variant of anaplastic large cell lymphoma (NR-ALCL) is a rare non-Hodgkin lymphoma. To our knowledge, we present thefirst study of NR-ALCL by FNAB cytology. Histologic confirmation was available for both patients. Both cases were positive for Ki-1 (CD-30) and were either T-cell or null-cell phenotype. FNAB specimens were highly cellular with a single-cell pattern composed of pleomorphic tumor cells, "hallmark" tumor cells, and a background rich in neutrophils that occasionally obscured tumor cells. Diagnosis on FNAB is difficult owing to the rarity of this tumor, its resemblance to Hodgkin lymphoma and other non-Hodgkin lymphomas that express CD30, its similarity to an infectious process, and its occasional confusion with metastatic carcinoma and melanoma. Reproducible cytologic features usually are present, and the diagnosis can be made conclusively by FNAB in conjunction with ancillary studies.     

Acetazolamide and renal ammoniagenesis.

The effect of acetazolamide on ammonia-producing enzyme systems was determined in vitro at concentrations comparable to those which have been shown to abolish ammonium excretion in vivo. No change in the activity of glutaminase or gamma-glutamyl transpeptidase could be observed at concentrations up to 0.2 mM acetazolamide, and concentrations up to 1 mM were without effect on D-glutamyltransferase activity. Therefore, the effect of acetazolamide to abolish ammonium excretion cannot be explained by an action of the drug to inhibit ammoniagenesis.     

Lung surfactant gelation induced by epithelial cells exposed to air pollution or oxidative stress

Lung surfactant lowers surface tension and adjusts interfacial rheology to facilitate breathing. A novel instrument, the interfacial stress rheometer (ISR), uses an oscillating magnetic needle to measure the shear viscosity and elasticity of a surfactant monolayer at the air-water interface. The ISR reveals that calf lung surfactant, Infasurf, exhibits remarkable fluidity, even when exposed to air pollution residual oil fly ash (ROFA), hydrogen peroxide (H2O2), or conditioned media from resting A549 alveolar epithelial cells (AEC). However, when Infasurf is exposed to a subphase of the soluble fraction of ROFA- or H2O2-treated AEC conditioned media, there is a prominent increase in surfactant elasticity and viscosity, representing two-dimensional gelation. Surfactant gelation is decreased when ROFA-AEC are pretreated with inhibitors of cellular reactive oxygen species (ROS), or with a mitochondrial anion channel inhibitor, as well as when A549-rho0 cells that lack mitochondrial DNA and functional electron transport are investigated. These results implicate both mitochondrial and nonmitochondrial ROS generation in ROFA-AEC-induced surfactant gelation. A549 cells treated with H2O2 demonstrate a dose-dependent increase in lung surfactant gelation. The ISR is a unique and sensitive instrument to characterize surfactant gelation induced by oxidatively stressed AEC.     

Relative motion of lung and chest wall promotes uniform pleural space thickness

The pleural space is modeled in two dimensions as a thin layer of fluid separating a deformable membrane and a rigid surface containing a bump. We computed the steady-state membrane configuration and fluid pressure distribution during relative sliding of the two surfaces. For physiologically relevant values of membrane tension, shear flow-induced pressures near the bump and far-field pressure gradients are similar to those measured in vivo within the pleural space (e.g. Lai-Fook et al.) [J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 56 (1984) 1633-1639]. Deformation of the membrane over the bump suggests that the pressure field generated by the sliding motion promotes an even layer of fluid in the pleural space, preventing asperities from touching. Results also suggest a possible mechanism for pleural fluid redistribution during breathing, whereby irreversible fluid motion is associated with the deformability of the membrane.