Synthesis, binding and bioactivity of gamma-methylene gamma-lactam ecdysone receptor ligands: advantages of QSAR models for flexible receptors.

Nuclear hormone receptors, such as the ecdysone receptor, often display a large amount of induced fit to ligands. The size and shape of the binding pocket in the EcR subunit changes markedly on ligand binding, making modelling methods such as docking extremely challenging. It is, however, possible to generate excellent 3D QSAR models for a given type of ligand, suggesting that the receptor adopts a relatively restricted number of binding site configurations or 'attractors'. We describe the synthesis, in vitro binding and selected in vivo toxicity data for gamma-methylene gamma-lactams, a new class of high-affinity ligands for ecdysone receptors from Bovicola ovis (Phthiraptera) and Lucilia cuprina (Diptera). The results of a 3D QSAR study of the binding of methylene lactams to recombinant ecdysone receptor protein suggest that this class of ligands is indeed recognised by a single conformation of the EcR binding pocket.

Role of CD95-mediated adipocyte loss in autoimmune lipodystrophy.

CONTEXT: Lipodystrophies are rare disorders characterized by the selective loss of adipose tissue. Metabolic complications increase in severity with the extent of fat loss. In some forms of acquired lipodystrophy, the loss of fat is suggested to be a result of autoimmune destruction of adipocytes. Here, the pathogenic mechanism is still poorly understood. OBJECTIVE: We have analyzed sc adipose tissue from a 5-yr-old girl with ongoing fat loss by immunohistochemistry. Using cultured human preadipocytes and adipocytes, we elucidated a possible mechanism leading to adipocyte loss in this patient. RESULTS: Analysis of adipose tissue samples of the patient with acquired lipodystrophy obtained from skin areas affected by panniculitis suggested that loss of adipocytes was mediated by CD95-induced apoptosis. Regression of adipose tissue was accompanied by lymphohistiocytic infiltration/inflammation and increased serum levels of inflammatory cytokines interferon-gamma and TNF-alpha. In vitro studies with human adipocytes demonstrated that interferon-gamma and TNF-alpha are able to up-regulate CD95 expression and enhance CD95-death-inducing signaling complex formation resulting in a robust sensitization for CD95-mediated apoptosis. CONCLUSION: We have identified here a possible mechanism responsible for the loss of adipocytes by apoptosis in autoimmune lipodystrophy.

Binding inhibitors of the bacterial sliding clamp by design.

The bacterial replisome is a target for the development of new antibiotics to combat drug resistant strains. The ß(2) sliding clamp is an essential component of the replicative machinery, providing a platform for recruitment and function of other replisomal components and ensuring polymerase processivity during DNA replication and repair. A single binding region of the clamp is utilized by its binding partners, which all contain conserved binding motifs. The C-terminal Leu and Phe residues of these motifs are integral to the binding interaction. We acquired three-dimensional structural information on the binding site in ß(2) by a study of the binding of modified peptides. Development of a three-dimensional pharmacophore based on the C-terminal dipeptide of the motif enabled identification of compounds that on further development inhibited α-ß(2) interaction at low micromolar concentrations. We report the crystal structure of the complex containing one of these inhibitors, a biphenyl oxime, bound to ß(2), as a starting point for further inhibitor design.

Breast reduction: modified "Lejour technique" in 500 large breasts.

BACKGROUND: The "minimal scar technique" for breast reduction, developed by Marchac, Lassus, and Lejour, has become an increasingly practiced alternative to standard operative procedures. METHODS: The authors introduced the modified "Lejour technique" in nearly 500 breast reductions in 250 overweight patients (adipose breasts) with a resection weight of more than 700 g. Their technique is a step-wise modification of the following procedures, resulting from their experience with complications and outcomes. Planning of the nipple-areola complex is carried out for each patient, and the glandular body is undermined only centrally and atraumatically, without liposuction. The superior mastopexy suture is waived in favor of the submammary fold being fixed using three H points. The three H points serve as a pivot by which later sagging is avoided. The skin closure does not have a shaping function without tension. The vertical pleated suture is not forced but adjusted to the retraction ability of the patient's skin. Use of the vertical pleated suture is limited; in cases of longer incisions, it is combined with a horizontal submammary transverse pleated suture. RESULTS: In 250 patients with an average follow-up of 4.2 years, the average resection weight was 985 g for the right breast and 923 g for the left. The operation lasted from 120 to 180 minutes. The results were evaluated as very good in 75 percent, good in 19 percent, satisfactory in 5 percent, and unsatisfactory in 1 percent. The complication rate was 14 percent. CONCLUSIONS: The authors' experience has shown that this technique can be applied as a standard technique. It is particularly suitable for larger breasts, because it reduces aesthetic deficiencies and simplifies the reduction technique.