No abstract

This paper reports the detailed composition of molecular species of the phosphatidylcholines (PCs) in pulmonary surfactant from calves. PC isolated by thin-layer chromatography (TLC) was converted to benzoylated diradyl glyceride derivatives, which were separated by TLC according to linkage group. Quantification of linkage groups by analysis of total fatty acid content demonstrated that surfactant PC contained 97.2% diacyl, 2.4% alkyl-acyl, and 0.4% alkenyl-acyl compounds. The diacyl and alkyl-acyl diglyceride derivatives were separated into individual molecular species by high-performance liquid chromatography. Four major species constituted 87% of the diacyl compounds. Dipalmitoyl phosphatidylcholine (DPPC) was the most abundant constituent, contributing 41% of the total PC. A second disaturated species, palmitoyl-myristoyl phosphatidylcholine (PMPC), also contributed an additional 12% of total PC. At least 65% of PMPC occurred as the 1-palmitoyl-2-myristoyl/isomer, which has a lower melting point than the 1-myristoyl-2-palmitoyl compound. These results show that most of pulmonary surfactant PC is a relatively simple mixture, that numerous minor compounds are present in small but possibly important amounts, and that in surfactant from calves, the widely reported estimate that DPPC constitutes 60% of surfactant PC is too large by 50%.

Soybean (Glycine max [L.] Merr.) root nodules contain the enzymes of the ascorbate-glutathione pathway to minimize oxidative damage. In the present study, fractionation and immunocytochemistry were used to determine the subcellular location of the enzymes of this pathway. AI1 four enzymes (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase) were present in the soluble fraction from nodule plant cells and in isolated mitochondria. No activity was detected in peroxisomes. Bacteroids contained glutathione reductase but not the other enzymes of this pathway. lmmunogold localization indicated that ascorbate peroxidase was present in the cytosol of infected and uninfected cells but not in the peribacteroid space. Results of immunogold and immunofluorescence studies indicated that monodehydroascorbate reductase was located primarily in the cell wall, suggesting that ascorbate regeneration in the cytoplasm may proceed primarily through the action of dehydroascorbate reductase. The possible roles of monodehydroascorbate reductase in cell wall metabolism are discussed.

The purpose of this study is to examine rates of nicotine, marijuana, and alcohol use as well as patterns of problematic substance use and posttraumatic stress disorder (PTSD) symptoms in inner-city adolescent girls. One hundred four adolescents who obtained medical care at a hospital-based adolescent clinic were systematically surveyed for trauma exposure, posttraumatic stress symptoms, and substance use. A subset (N = 54, 52%) of girls completed a semistructured psychiatric diagnostic interview (K-SADS-PL) to ascertain timing of PTSD symptoms relative to substance use. Compared with traumatized girls without PTSD, girls with full and partial PTSD were significantly more likely to use nicotine, marijuana, and/or alcohol on a regular basis. Fifteen girls met criteria for both PTSD and a substance-use disorder. For 80% of these girls, the age of onset of PTSD was either before or concurrent with the onset of their substance-use disorder. Inner-city adolescent girls with PTSD exhibit problematic substance use and may be at high risk of developing a comorbid substance-use disorder.

No abstract

Thirty female subjects were followed up an average of 4.6 years after being hospitalized for anorexia nervosa. Insight into illness, symptoms, and treatment was rated for index hospitalization and assessed at follow up using the Schedule for Assessment of Insight. In addition, subjects were interviewed and assessed for level of function, symptoms of eating disorders, and the presence of significant psychopathology. The Insight Rating at index hospitalization was correlated with the Global Insight Score at follow up and with EAT score at follow up. Subjects with longer lengths of stay and greater increase in Body Mass Index during index hospitalization had higher levels of insight at both times of measurement. At followup, both Global Insight Score and assessment of subjects' ability to acknowledge illness were correlated with a variety of positive outcome measures, suggesting that insight may be an important therapeutic factor to consider in assessment and treatment of anorexia nervosa.

No abstract

Adsorption of pulmonary surfactant to an air−water interface lowers surface tension (γ) at rates that initially decrease progressively, but which then accelerate close to the equilibrium γ. The studies here tested a series of hypotheses concerning mechanisms that might cause the late accelerated drop in γ. Experiments used captive bubbles and a Wilhelmy plate to measure γ during adsorption of vesicles containing constituents from extracted calf surfactant. The faster fall in γ reflects faster adsorption rather than any feature of the equation of state that relates γ to surface concentration (Γ). Adsorption accelerates when γ reaches a critical value rather than after an interval required to reach that γ. The hydrophobic surfactant proteins (SPs) represent key constituents, both for reaching the γ at which the acceleration occurs and for producing the acceleration itself. The γ at which rates of adsorption increase, however, is unaffected by the Γ of protein in the films. In the absence of the proteins, a phosphatidylethanolamine, which, like the SPs, induces fusion of the vesicles with the interfacial film, also causes adsorption to accelerate. Our results suggest that the late acceleration is characteristic of adsorption by fusion of vesicles with the nascent film, which proceeds more favorably when the Γ of the lipids exceeds a critical value.