Bacterial lipopolysaccharide can enter monocytes via two CD14-dependent pathways

Host recognition and disposal of LPS, an important Gram-negative bacterial signal molecule, may involve intracellular processes. We have therefore analyzed the initial pathways by which LPS, a natural ligand of glycosylphosphatidylinositol (GPI)-anchored CD14 (CD14-GPI), enters CD14-expressing THP-1 cells and normal human monocytes. Exposure of the cells to hypertonic medium obliterated coated pits and blocked 125I-labeled transferrin internalization, but failed to inhibit CD14-mediated internalization of [3H]LPS monomers or aggregates. Immunogold electron microscope analysis found that CD14-bound LPS moved principally into noncoated structures (mostly tubular invaginations, intracellular tubules, and vacuoles), whereas relatively little moved into coated pits and vesicles. When studied using two-color laser confocal microscopy, internalized Texas Red-LPS and BODIPY-transferrin were found in different locations and failed to overlap completely even after extended incubation. In contrast, in THP-1 cells that expressed CD14 fused to the transmembrane and cytosolic domains of the low-density lipoprotein receptor, a much larger fraction of the cell-associated LPS moved into coated pits and colocalized with intracellular transferrin. These results suggest that CD14 (GPI)-dependent internalization of LPS occurs predominantly via noncoated plasma membrane invaginations that direct LPS into vesicles that are distinct from transferrin-containing early endosomes. A smaller fraction of the LPS enters via coated pits. Aggregation, which greatly increases LPS internalization, accelerates its entry into the nonclathrin-mediated pathway.     

A preliminary study of partial hospital management of severe obsessive-compulsive disorder

OBJECTIVE: The study examined the effectiveness of a partial hospital treatment program combining behavioral therapy, medication, and psychosocial intervention for severe and treatment-resistant obsessive-compulsive disorder. METHODS: A total of 58 patients with a primary diagnosis of obsessive-compulsive disorder who underwent treatment in a partial hospital program were assessed at baseline, at program discharge, and at six-, 12-, and 18-month follow-ups. Obsessive-compulsive symptoms, depression, anxiety symptoms, and global functioning were rated. RESULTS: The majority of patients (71 percent) met the criterion for a successful outcome, which was a 25 percent decrease in score on the Yale-Brown Obsessive Compulsive Scale (YBOCS). Fifty-five percent finished the program with YBOCS scores of 16 or less, indicating only mild symptoms. Most of these patients sustained their improvement at six, 12, and 18 months after discharge, and many showed further improvement with continued outpatient management. CONCLUSIONS: The partial hospital treatment program for obsessive-compulsive disorder appears to be an effective intervention that should be implemented and investigated further.     

Physiologically responsive gene therapy

The goal of physiologically responsive gene therapy is to allow a host's endogenous regulatory mechanisms to control the production of therapeutic proteins (effectors). Ideally, effector production would be switched on in response to specific signals, stay within therapeutic limits and be switched off when no longer needed. In this way, the unwanted consequences of constitutive, high-level effector expression could be avoided. While recent studies have shown that transgenes can be regulated within animal hosts, they have also highlighted significant problems that require much further research.     

Nanocellulose Reinforced Chitosan Composite Films as Affected by Nanofiller Loading and Plasticizer Content

ABSTRACT: Chitosan is a biopolymer obtained by N-deacetylation of chitin, produced from shellfish waste, which may be employed to elaborate edible films or coatings to enhance shelf life of food products. This study was conducted to evaluate the effect of different concentrations of nanofiller (cellulose nanofibers, CNF) and plasticizer (glycerol) on tensile properties (tensile strength—TS, elongation at break—EB, and Young's modulus—YM), water vapor permeability (WVP), and glass transition temperature (T_g) of chitosan edible films, and to establish a formulation to optimize their properties. The experiment was conducted according to a central composite design, with 2 variables: CNF (0 to 20 g/100 g) and glycerol (0 to 30 g/100 g) concentrations in the film (on a dry basis), which was produced by the so-called casting technique. Most responses (except by EB) were favored by high CNF concentrations and low glycerol contents. The optimization was based on maximizing TS, YM, and T_g, and decreasing WVP, while maintaining a minimum acceptable EB of 10%. The optimum conditions were defined as: glycerol concentration, 18 g/100 g; and CNF concentration, 15 g/100 g. AFM imaging of films suggested good dispersion of the CNF and good CNF-matrix interactions, which explains the good performance of the nanocomposite films. Practical Application: Chitosan is a biodegradable polymer which may be used to elaborate edible films or coatings to enhance shelf life of foods. This study demonstrates how cellulose nanofibers (CNF) can improve the mechanical and water vapor barrier properties of chitosan films. A nanocomposite film with 15% CNF and plasticized with 18% glycerol was comparable to some synthetic polymers in terms of strength and stiffness, but with poorer elongation and water vapor barrier, indicating that they can be used for applications that do not require high flexibility and/or water vapor barrier. The more important advantage of such films when compared to synthetic polymer films is their environmentally friendly properties.     

Phosphatidylinositides bind to plasma membrane CD14 and can prevent monocyte activation by bacterial lipopolysaccharide

Although bacterial lipopolysaccharides (LPS) and several other microbial agonists can bind to mCD14 (membrane CD14), a cell-surface receptor found principally on monocytes and neutrophils, host-derived mCD14 ligands are poorly defined. We report here that phosphatidylinositol (PtdIns), phosphatidylinositol-4-phosphate, and other phosphatidylinositides can bind to mCD14. Phosphatidylserine (PS), another anionic glycerophospholipid, binds to mCD14 with lower apparent affinity than does PtdIns. LPS-binding protein, a lipid transfer protein found in serum, facilitates both PS- and PtdIns-mCD14 binding. PtdIns binding to mCD14 can be blocked by anti-CD14 monoclonal antibodies that inhibit LPS-mCD14 binding, and PtdIns can inhibit both LPS-mCD14 binding and LPS-induced responses in monocytes. Serum-equilibrated PtdIns also binds to mCD14-expressing cells, raising the possibility that endogenous PtdIns may modulate cellular responses to LPS and other mCD14 ligands in vivo.     

Quantitative Limulus lysate assay for endotoxin activity: aggregation of radioiodinated coagulogen monomers

This communication describes a modification of the Limulus lysate assay which allows precise quantitation of picograms of bacterial lipopolysaccharide activity. The method measures the incorporation of 125I-labeled coagulogen monomers into the lysate clot as a function of lipopolysaccharide concentration. The method is more precise and requires less lysate than the previously described quantitative assays for endotoxin activity.     

Family therapy for the treatment of a conversion reaction: A case study.

Presents the case of a 14-yr-old girl with problems of incessant eructation on an intermittent basis for 9 yrs and irrational fears for 4 yrs. The family system suffered from dysfunctional patterns of interaction; contingency contracting rapidly produced positive results. The elimination of the conversion reaction and irrational fears is attributed to conceptualizing them as operants and treating them according to operant conditioning principles. The increased ability of the family members to meet each other's needs was a consequence of their learning to negotiate quid-pro-quo contracts. Follow-ups at 3 and 6 mo and l and 2 yrs revealed that the S was symptom-free and that interpersonal relationships among family members continued to improve. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)