Quantitation of 'junctional feet' content in two types of muscle fiber from hind limb muscles of the rat

1. Transverse tubules in fibers from rat soleus and extensor digitorum longus (EDL) muscles of the rat were infiltrated with silver dichromate (black reaction of Golgi). This provides a faithful, high-contrast outline of the tubules, which allows distinction between segments involved in junction formation with the sarcoplasmic reticulum and segments that are free. 2. Electron micrographs of semithin transverse sections were used to quantitate T tubule parameters and to measure cross-sectional area and perimeter of individual fibers. Thin sections and data from the literature were used to obtain the contribution of caveolae to external surface area and the frequency of junctional feet along the junctional T tubule membrane. 3. From the above data we calculate the ratio of number of feet to total external surface area for a given fiber segment. The ratio is compared with data in the literature on the total amount of 'charge movement' (in nC/uF of total external surface area). 4. The average feet/surface area ratio is twice as large in EDL than in soleus fibers, while the charge movement is up to five-fold larger. Probably some of the total charge movement is not directly associated with events related to the turning on of the SR permeability to calcium.     

On-Line Optical and Morphological Studies of Silver Nanoparticles Growth Formed by Nanosecond Laser Irradiation of Silver-Exchanged Silicate Glass

Silver-exchanged silicate glass has been irradiated by 532-nm pulsed Nd:YAG laser in order to locally form metallic nanoparticles. The particular interest of this process is to locally control the silver nanoparticles (NPs) growth. Silver ions are exchanged with sodium ions near the glass surface after dumping of a silicate glass few minutes in silver and sodium nitrates molten salt. A low-energy density laser exposure (0.239 J/cm²) chosen at the ablation threshold allows to observe the kinetics of the silver NPs growth according to the increasing shots number. An on-line optical measurement is carried out after each shot to identify the most important steps during the irradiation process. According to this measurement, we have determined four steps highlighted by UV/Visible spectrophotometry and we have identified the influence of located surface plasmon resonance. Three combined material analysis methods were used to understand the glass/laser interaction mechanism: we outlined the material volume variations by profilometric method, the element distribution by scanning electron microscopy and finally the structural distribution of the irradiated region by a local infrared investigation. The trend for NPs formation revealed by the UV/Visible spectrophotometry is thus explained by the formation of a ring expelled from a central hole. We highlight that the on-line extinction measurement can be used to data process the NPs evolution.     

Design of antimicrobial compounds based on peptide structures

New antimicrobial compounds are of major importance because of the growing problem of bacterial resistance and antimicrobial peptides have been gaining a lot of interest. Their mechanism of action, however, is often obscure. Here a set of non-peptidic compounds with antimicrobial activity are presented that have been designed based on criteria derived from three-dimensional structures of antimicrobial peptides. Even though only a small set of compounds has been designed, the activity immediately matches that of the original peptides, supporting the proposed criteria for activity, i.e. not the peptidic nature of antimicrobial peptides is responsible for their activity but rather the proper arrangement of the relevant functional groups.     

An algorithmic approach to upper arm contouring

There has been a renewed interest in upper arm contouring given the recent advances and subsequent patient interest in weight loss. Patients undergoing bariatric surgery are often left with a significant amount of redundant skin and laxity of their upper extremity. Some patients within this group have excess fat in their upper arms with relatively good skin tone, while others have a paucity of excess fat with a significant amount of redundant skin. The optimal treatment for each patient can vary. A clinical algorithm is presented that is designed to select the best method for upper arm contouring based on the aesthetic analysis of the upper arm. Case examples are provided demonstrating results that were obtained by following this algorithm.     

Metapopulation dynamics in a regional population of the blue-winged grasshopper (Oedipoda caerulescens; Linnaeus, 1758)

For two consecutive years we registered the presence (or absence) of blue winged grasshoppers (Oedipoda caerulescens; Linnaeus, 1758) on 312 habitat patches of differing size in a region of more than 3000 ha. The data show that presence of grasshoppers on a habitat patch is dependent on patch size as well as on patch isolation. We used an ecological incidence model to describe the metapopulation dynamics of the regional population and derived the parameters for this model from presence-absence data and observations of Oedipoda dispersion. The analysis shows that local extinction of grasshopper populations is influenced by strong fluctuations of environmental conditions and that for a number of small patches in our region recolonization is important for the presence of O. caerulescens. Colonization probability, as derived using the incidence model, is in good agreement with estimates from a population genetical analysis.     

Effects of pioglitazone versus simvastatin on biomarkers of inflammation in patients on high cardiovascular risk

High levels of fetuin-A has been linked to cardiovascular disease, possibly via modulating low-grade systemic inflammation. We performed a subanalysis from the PIOSTAT study to investigate a possible link between fetuin-A and the inflammatory biomarker hs-CRP. 66 nondiabetic individuals at cardiovascular risk were randomized to either pioglitazone, simvastatin, or the combination of both, and followed for 12 weeks. At study endpoint, correlations between serum fetuin-A, hs-CRP, blood lipids, PAI-1, MMP-9, HOMA-IR, and liver transaminases were investigated by Spearman rank correlation. Changes in fetuin-A concentration did not correlate to changes in hs-CRP (r=0.19, p=0.16). A positive correlation was found for change of HOMA-IR value (r=0.33, p=0.01) and for the AST/ALT ratio (p<0.05). Our data suggest that the previously observed correlation between elevated circulating fetuin-A and hs-CRP in epidemiological studies may not reflect a causal relationship in nondiabetic patients on high cardiovascular risk.     

Proteins of the Bacillus stearothermophilus ribosome: Crystallization of protein L6

Crystals of ribosomal protein L6 from Bacillus stearothermophilus suitable for high resolution structural studies have been obtained. Crystals are hexagonal with space group P6₁22 (or the enantiomorph P6₅22) and cell dimensions a = b = 72.7 Å, c = 124.9 Å. A search for heavy atom derivatives is in progress.