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We studied the accumulation of surfactant in the alveoli and airways from birth to 10 h of age in 60 lambs delivered prematurely at a mean gestational age of 136 days. The lambs were delivered by cesarean section and ventilated by varying peak inspiratory pressures only to normalize arterial blood gas and pH values. Alveolar surfactant accumulation was measured either by alveolar wash after timed sacrifice or by repetitive sampling of the airways using an isotope dilution technique. The fall in specific activity of phosphatidylcholine with time was measured after the intratracheal administration of either a trace dose of 3H-labeled natural surfactant and synthetic 14C-dipalmitoylphosphatidylcholine (DPPC) at birth or a treatment dose of the same mixture at 5 h of age (about 55 mg of total surfactant lipid/kg body weight). From the change in phosphatidylcholine-specific activities and the quantities and specific activities of phosphatidylcholine measured in alveolar washes, we found that the surfactant pool sizes as estimated by alveolar wash or by the isotope dilution technique were similar. The pool size of alveolar surfactant increased fourfold from birth to 20 min of age and doubled again by 10 h of age. The shape of the curve for the accumulation of alveolar surfactant versus time was independent of the final pool size achieved at 10 h of age. Sonicates of DPPC when mixed with either a trace amount or a treatment dose of natural surfactant were treated by the premature lung in a manner indistinguishable from the phosphatidylcholine associated with natural surfactant.

Airway samples from infants with respiratory distress syndrome were recovered by suction immediately after tracheal intubation for respiratory failure. The minimum surface tension of these airway samples was 27.3 +/- 3.0 dynes/cm. Surfactant with low surface tension (1.4 +/- 1.0 dynes/cm) was recovered from these samples by centrifugation; the supernatant fractions from the samples had high minimum surface tensions. The supernatant fractions contained soluble proteins that inhibited the surface tension-lowering properties of natural sheep surfactant. Similar supernatant fractions collected from infants intubated for reasons other than respiratory distress syndrome were much less inhibitory to sheep surfactant. The minimum surface tension of sequential daily airway samples from infants with respiratory distress syndrome fell progressively to 5.7 +/- 2.4 dynes/cm on the day of extubation. These results document the presence of proteins in the airways of infants with respiratory distress syndrome that inhibit the surface tension-lowering properties of surfactant.

Several surface modification techniques are currently being used to improve the biocompatibility of blood-contacting devices. These include the immobilization of bioactive materials to prevent thrombus generation and platelet activation, the incorporation of hydrophilic grafts onto practical hydrophobic surfaces (polyurethanes) to reduce protein adsorption, and the concept of microdomain-phase separated surfaces to regulate cellular and protein adhesion.

The Great Sensations Program is a nutrition-education project developed for high school students. It was designed to (a) decrease students' consumption of salty snacks and (b) increase students' consumption of fresh fruit snacks. The overall programs were designed following principles of social learning: informative instruction, participatory classroom activities, personal goal setting, feedback, and reinforcement. The program was delivered in six lessons during regular health-education classes. A parental involvement program consisted of mailers and telephone calls to parents to teach them to encourage changes in student snacking habits. A schoolwide program was designed to provide out-of-class peer support for student modifications in salty snack foods. The program was evaluated in one high school using a 2 X 2 design. A second high school served as a no-treatment control. Program assessments were made at both schools before and after the classes, at the end of the school year, and the following fall the next school year following summer vacation. The schoolwide media program was effective in decreasing consumption of salty snack foods and in increasing consumption of target snack foods. However, only those students receiving classroom instruction maintained those changes until the end of the school year. No changes were maintained across summer vacation. These outcomes suggest that school programs developed using principles of social learning may be effective in facilitating important behavior changes at home and at school.

Three-day-old rabbits were given intratracheal injections of radiolabeled natural sheep surfactant, rabbit surfactant, or liposomes of dipalmitoylphosphatidylcholine that contained greater than three times the quantity of phosphatidylcholine present in the endogenous surfactant pool. The recoveries of radiolabeled phosphatidylcholine and total phosphatidylcholine in alveolar washes, lung tissue, and total lung (alveolar washes plus lung tissue) were measured for 72 h. Approximately half of the two natural surfactants rapidly became lung tissue associated, and phosphatidylcholine derived from the rabbit surfactant was cleared from the total lung twice as rapidly as was the phosphatidylcholine from sheep surfactant (20.7% versus 10.4% of the amount present at zero time/24 h, p less than .05). The alveolar surfactant pool size did not decrease despite the clearance of the exogenously administered material. The liposomes of dipalmitoylphosphatidylcholine were cleared from the total lung at the same rate as the rabbit surfactant phosphatidylcholine; however, compared to the natural surfactants, much less of this material became lung tissue associated. The administration of the natural rabbit surfactant did not decrease the amount of radiolabeled choline, palmitic acid, or 32P that was incorporated into lung phosphatidylcholine or the amount of labeled phosphatidylcholine that was secreted to the alveoli. However, sheep surfactant increased the percent of radiolabeled phosphatidylcholine recovered by alveolar wash. These experiments document differences in clearance rates, tissue and alveolar association patterns, and subtle effects on endogenous surfactant metabolism for two surfactants and liposomes of dipalmitoylphosphatidylcholine following intratracheal administration. Uniform metabolic responses should not be anticipated following treatments with different surfactant preparations.

After delivery by cesarean section at 133-136 days gestational age, 18 lambs were supported with infant ventilators. Peak inspiratory pressure was the only ventilator setting that was changed in an attempt to normalize PCO2. The lambs were retrospectively divided into two groups based on their respiratory status before treatment. Ten lambs with PCO2 values of 38 +/- 2 mmHg (mean +/- S.E.) at 5 h of age were treated with a 15-ml suspension containing 50 mg natural sheep surfactant lipid/kg body weight. After surfactant instillation, pH fell, PCO2 increased and compliance/kg decreased transiently. Surfactant treatment did not reduce the respiratory support that these lambs required. Eight lambs with PCO2 values of 68 +/- 3 mmHg at 3 +/- 0.8 h of age responded to surfactant instillation with a decrease in PCO2 and an increase in PO2 and pH. In both groups of lambs heart rates, mean aortic pressures, and mean pulmonary artery pressures changed little after surfactant instillation. Cardiac outputs and regional blood flows measured before and after surfactant treatment were unchanged. Instillation of surfactant suspensions to premature lambs did not adversely affect cardiovascular status; however, some lambs did have a transient deterioration of lung function after surfactant instillation.

Monoclonal IgM cold agglutinins (CA) bind and, in the presence of complement, are cytotoxic to various mammalian cells. The impact of these autoantibodies on functional capacity of phagocytes has not been studied until now. Herein we report that sera with monoclonal IgM anti-I and anti-i CA significantly reduce adhesiveness, phagocytosis, phagocytic index, and intracellular bactericidal activity of human peripheral blood polymorphonuclear cells (PMNs) at 37 degrees C and 24 degrees C. Anti-i CA were more active than anti-I. Sera with monoclonal IgMs without CA activity reduced the total number of ingested bacteria but otherwise had no effect on phagocytic functions. There was no difference in the degree of inhibition when anti-i and anti-I CA were tested against cord, maternal, and adult PMNs. Chromatographically purified a-I and a-i CA inhibited markedly phagocytosis in concentrations as low as 1 mg/ml. Phagocytic activity of peripheral blood monocytes was inhibited by CA at 18 degrees C but not at 24 degrees C or 37 degrees C. Pepsin digestion or reduction and alkylation of chromatographically pure IgM CA abolished completely their inhibitory activity. Thus, in physiological temperatures, monoclonal IgM cold agglutinins impair various phagocytic functions of human phagocytes. It may add to the susceptibility to infections in patients in which such autoantibodies are synthesized.

One hundred and twenty sera with monoclonal immunoglobulin M's (IgM's) were tested for cryptic cold agglutinin activity against papain- and neuraminidase-treated adult and cord red blood cells (RBC). Fifteen sera (12.5%) agglutinated papain-treated RBC. Fourteen of these 15 sera also agglutinated neuraminidase-treated RBC. Ten additional sera agglutinated neuraminidase-treated but not papain-treated cells. Three patterns were observed among agglutinators of papain-treated RBC: either predominant agglutination of adult RBC, or of cord RBC or equal reaction, thus resembling I, i and non-Ii patterns of conventional cold agglutinins. We propose to call these patterns, tentatively, Icr (cr for cryptic), icr, and non-Iicr, respectively. Purified monoclonal IgM's retained the above patterns. Eluates from enzyme-treated cells contained monoclonal IgM's. Investigation of neuraminidase-treated RBC has shown that in distinction to T-anti-T system (Thomsen-Friedenreich receptor system), the majority of sera with monoclonal IgM's agglutinated more strongly adult RBC, and some agglutinated more strongly cord RBC. There was no loss of agglutinating activity after repeat freezing and thawing of the sera. Thus, it seems that monoclonal IgM's which react with neuraminidase-treated RBC detect antigenic determinants different from the T antigen. Cryptic CA activity of IgM's should be added to the list of antibody activities of these monoclonal immunoglobulins.

A double blind trial of opipramol (Insidon) compared with placebo for a group of matched patients suffering from migraine has been carried out. The total number of the migraine attacks in a group of 14 patients on opipramol (as compared with the same patients during a pretreatment period of six weeks) showed a 33% reduction in the number of attacks experienced during the first six weeks. During a further consecutive six weeks after this on treatment, attacks were further reduced to 49% as compared with the pretreatment period. In the placebo group there was a 20% increase in the number of migraine attacks in the first six week treatment period as compared with the base line six weeks on no drugs. In the second consecutive six weeks migraine attacks were 2% more frequent than in the pretreatment period. These figures indicate that opipramol is a drug with considerable promise and effectiveness in the control of migraine attacks.

Prognosis for life in the Landry-Guillain-Barré-Strohl syndrome is dependent upon the development of respiratory and non-respiratory "complications" and their successful management. Review of the literature, a case history, and a study of 14 patients with this syndrome at the University Hospital, Edmonton, indicate that "complications" can be anticipated in virtually all areas of acute care management, including respiratory, gastrointestinal, urinary tract, central and autonomic nervous systems, metabolic, cardiovascular, and infectious disease. The proper management of patients with the Landry-Guillain-Barré-Strohl syndrome demands an awareness of the totality of care required and the presence of a hospital system that provides for vital system monitoring and support, and for ready interdisciplinary consultation.