OBJECTIVE: Maternal problem-solving abilities, as they related to specific child-rearing situations, were examined and compared among mothers of infants with failure to thrive (FTT) and a matched group of comparison mothers. METHODS: Participants were 37 mothers of children diagnosed with FTT and 37 mothers with normally growing children matched on three child variables and five maternal variables. Participants were administered a means-ends problem-solving measure specific to parents of young children and measures of language ability, depression, negative affect, and stressful life events. RESULTS: Multivariate analysis of covariance results supported our main study hypotheses that mothers of infants with FTT would generate fewer problem-solving strategies that would be judged of poorer quality (i.e., less likely to result in positive outcomes) than mothers of healthy, normally growing infants. There were no significant associations obtained among problem-solving variables and individual difference variables (e.g., depression, negative affect, and stressful life events). CONCLUSIONS: Limited maternal problem-solving abilities may contribute to FTT by interfering directly with the quality of nurturance, feeling, and caloric intake the child receives. Recommendations are made for future research and interventions with mothers of children with FTT.

Adolescent↗

PubMedDate not supplied

Ocular drug delivery of progesterone using nanoparticles.

The objective of this study was to evaluate ocular delivery of a lipid-soluble drug, [3H]progesterone, using nanoparticles. Polybutylcyanoacrylate nanoparticles loaded with [3H]progesterone were prepared by an emulsion polymerization technique using a hydrophilic continuous phase. The resulting nanoparticle suspension contained 2 x 10(-5) M progesterone. It was found that, at equilibrium, 99 per cent of the progesterone resided in the nanoparticles and the remainder in the aqueous phase indicating an excellent encapsulation efficiency. In addition, an appropriate control solution of progesterone was prepared, which did not contain polybutylcyanoacrylate. Concentrations of [3H]progesterone in various ocular tissues of the albino rabbit were monitored at various times following topical administration of either the nanoparticle suspension or the control solutions. Comparison of the concentration-time profiles indicates that tissue concentration of progesterone following topical administration of nanoparticles is generally four to five times less than that obtained with control solutions. This decreased concentration suggests that, due to the high affinity of progesterone for the nanoparticles, the drug is being made less available for absorption during its residence time in the precorneal area. The utility of nanoparticles as an ocular drug delivery system may depend on optimizing lipophilic-hydrophilic properties of the polymer-drug system, in addition to increasing retention efficiency in the precorneal pocket.

Animals↗

PubMedDate not supplied

Studies on the transport pathway of PBCA nanoparticles in ocular tissues.

The transport pathway of PBCA nanoparticles through the rabbit cornea and conjunctiva was studied using fluorescence microscopy. Nanoparticles were produced by an emulsion-polymerization process, purified by a GPC procedure, and labelled with rhodamine 6G or propidium iodide as fluorescent laser dyes. The stability of the dye label, particle diameter, and zeta potential of the nanoparticles were determined. Freshly excised rabbit cornea and conjunctiva were incubated with a suspension of labelled nanoparticles for about 30 min in standard perfusion cells. After incubation the particles were visualized, due to their fluorescent character, using laser scanning confocal microscopy. The results show a fluorescence signal inside the cells. In particular conjunctival cells showed an uptake of nanoparticles. Fluorescent particles were visually observed inside the cells, in what appeared to be vesicles or granules. Thus, either endocytosis of the nanoparticles by conjunctival tissue or lysis of the cell wall by nanoparticle metabolic degradation products, are possible explanations of the data. A fluorescence signal was also observed within corneal cells. Only a transcellular pathway was observed. A possible penetration through tight junctions was not noticed; moreover, penetration was observed only into the first two cell layers and no full tissue penetration occurred.

Animals↗

PubMedDate not supplied