Pharmacological and physiological characterization of d[Leu4, Lys8]vasopressin, the first V1b-selective agonist for rat vasopressin/oxytocin receptors

Recently, we synthesized and characterized the first selective V(1b) vasopressin (VP)/oxytocin receptor agonist, d[Cha(4)]arginine vasopressin. However, this agonist was only selective for the human receptors. We thus decided to design a selective V(1b) agonist for the rodent species. We started from previous observations showing that modifying [deamino(1),Arg(8)]VP in positions 4 and 8 altered the rat VP/oxytocin receptor selectivity. We synthesized a series of 13 [deamino(1),Arg(8)]VP analogs modified in positions 4 and 8. Among them, one seemed very promising, d[Leu(4), Lys(8)]VP. In this paper, we describe its pharmacological and physiological properties. This analog exhibited a nanomolar affinity for the rat, human, and mouse V(1b) VP receptors and a strong V(1b) selectivity for the rat species. On AtT20 cells stably transfected with the rat V(1b) receptor, d[Leu(4), Lys(8)]VP behaved as a full agonist on both phospholipase C and MAPK assays. Additional experiments revealed its ability to induce the internalization of enhanced green fluorescent protein-tagged human and mouse V(1b) receptors as expected for a full agonist. Additional physiological experiments were performed to further confirm the selectivity of this peptide. Its antidiuretic, vasopressor, and in vitro oxytocic activities were weak compared with those of VP. In contrast, used at low doses, its efficiency to stimulate adrenocorticotropin or insulin release from mouse pituitary or perfused rat pancreas, respectively, was similar to that obtained with VP. In conclusion, d[Leu(4), Lys(8)]VP is the first selective agonist available for the rat V(1b) VP receptor. It will allow a better understanding of V(1b) receptor-mediated effects in rodents.     

The effects of targeted deletion of the aromatase enzyme on prostatic contractile responses to noradrenaline in mice

This investigation aimed to see whether a change in the oestrogen to androgen ratio alters prostate contractility. Isolated organ bath studies using prostates from aromatase knockout (ArKO) mice which were homozygous (ArKO-/-) and heterozygous (ArKO+/-) for the disrupted aromatase cyp19 gene and wild-type littermates (ArKO+/+) were conducted. The distribution of noradrenergic nerves was visualized using the sucrose-potassium phosphate-glyoxylic acid method. ArKO-/- mice had increased prostate weights compared with ArKO+/+ mice. Frequency-response curves to electrical field stimulation (EFS; 0.5 ms pulse duration, 60 V, 0.1-20 Hz) yielded frequency-dependent contractions, while noradrenaline (10 nM-1 mM) and tyramine (1 muM-1 mM) produced concentration-dependent contractions. Prazosin (0.3 muM) attenuated the responses induced by noradrenaline and EFS in all mice (P/=0.506, n=10-13). Prostates from ArKO-/- and ArKO+/- mice were more sensitive to tyramine than prostates from ArKO+/+ mice (P<0.001, n=11-13). Dense adrenergic innervation of the prostate was similar in all mice. These results suggest that although the absence of aromatase increases prostatic growth, this translates only to a subtle and selective increase in contractility in mature mice.     

Neuromuscular electrical stimulation of completely paralyzed abdominal muscles in spinal cord-injured patients: a pilot study

STUDY DESIGN: Prospective placebo-controlled. OBJECTIVE: The effect of abdominal neuromuscular electrical stimulation (NMES) in patients with spinal cord injury. The principal parameters observed in this study are lung capacity, colonic transit, patient satisfaction of used method and of aesthetics effect on abdominal wall. SETTINGS: Centre de Traumatologie et de Réadaptation, Brussels, Belgium. METHODS: A total of 10 volunteers participated in this study and were assigned to two groups-the effective electrical stimulation group (ESG) and the placebo-controlled group (PG). NMES of abdominal muscles was performed 25 min per day for 8 weeks. RESULTS: NMES significantly decreased forced vital capacity (FVC) in ESG but not in PG. In ESG, colonic transit was accelerated in ascending, transverse and descending colon but transit in rectosigmoideum was not affected. In PG, no variations in colonic transit were observed. Satisfaction scale shows a better influence on aesthetics effect in ESG than in PG. CONCLUSION: This pilot study shows that NMES of paralyzed abdominal muscles positively affects colonic transit except in rectosigmoideum segment and negatively affects FVC. It could be a simple self-used method to regulate colonic transfer with considerably good cosmetic effect on abdominal wall. However, regular verification of FVC will probably be necessary.     

Influence of routine assessment of fractional flow reserve on decision making during coronary interventions

In complex coronary artery disease, it is sometimes difficult to determine which lesions are associated with reversible ischemia and should be stented. Fractional flow reserve (FFR) is an established objective methodology to indicate which lesions produce ischemia. Despite this, the selection of lesions to be stented is often based on the subjectively interpreted angiogram alone. The aim of this study in patients admitted for elective percutaneous intervention (PCI) was to evaluate the change in strategy if the decision to intervene was based on FFR measurement rather than on angiographic assessment. Two hundred fifty consecutive patients (471 arteries) scheduled for PCI were included in this study. All stenoses >or=50% by visual estimation and initially selected to be stented by 3 independent reviewers were assessed by FFR measurements. If FFR was <0.75, stenting was performed; if FFR was >or=0.75, no interventional treatment was given. Optimal pressure measurements were obtained in 452 lesions (96%). Diameter stenosis was 62 +/- 12%, and FFR was 0.67 +/- 0.17 for the entire group. In 68% of the stenoses, initial strategy as assessed from the angiogram was followed, and in 32%, there was a change in the planned approach based on FFR. In 48% of the patients, there was >or=1 lesion in which the treatment decision was changed after physiologic measurements. In conclusion, in this prospective, nonselective, but complete study representing the real world of PCI, 32% of the coronary stenoses and 48% of patients would have received a different treatment if the decision had been based on angiography only, stressing the utility of physiologic assessment in refining decision making during PCI.     

Genetic predisposition to rheumatoid arthritis in a Tuscan (Italy) ancient human remain

Rheumatoid arthritis (RA) is currently believed to have originated in America, and after the discovery of this continent in 1492, to have been exported to the Old World. We evaluated the genetic predisposition to RA in the "Braids Lady" from Arezzo (Italy), a partially mummified woman's body dating back to the end of 1500 AD which presents the anatomical and pathological features of this disease. The study of the polymorphic HLA-DRB1 locus, which includes alleles strongly associated with RA onset, has received much attention over recent years, especially the loci codifying for the DR1 and DR4 antigens, widely represented in the Mediterranean population, and for DR14, widespread among Native Americans. Molecular analysis was performed on extracts of DNA from the mummy, firstly from histological bone sections and then from the whole bone. Two different HLA typing techniques, PCR-sequence-specific oligonucleotides (PCR-SSO) and PCR-sequence-specific primers (PCR-SSP), were employed to identify HLA-DRB alleles. Both genotyping methods showed that the "Braids Lady" carried the DRB1*0101 allele, the serological equivalent of the DR1 antigen. Although the possession of RA risk factor genes cannot be considered a diagnostic marker, the positive result of the Italian mummy for DRB1*0101 and the RA features present, support the idea that this pathology was present in the Old World from at least the mid-16th century. A pathogenetic hypothesis of RA which might well explain its worldwide diffusion is the "molecular mimicry", resulting from a cross-reactive antibody response between certain microbial antigens and shared epitopes of specific HLA-DR1, DR4 and DR14 susceptibility alleles, the frequency of which varies among different ethnic groups.     

Dexamethasone sodium phosphate-loaded Chitosan based delivery systems for buccal application

Chitosan (CH) was used as a biocompatible and bioadhesive polymer material to prepare solid dispersions as well as hydrogels loaded with dexamethasone sodium phosphate (DSP), a steroidal anti-inflammatory agent clinically used for treatment of different mouth diseases. Binary solid dispersions at various drug-to-polymer weight ratios were prepared by freeze-drying; their direct compression gave tablets which were characterized for the swelling behaviour and drug release in vitro. Similarly, DSP-loaded hydrogels composed of CH and glycerine were prepared and characterized. CH and DSP showed a good physical compatibility. A slow and prolonged release of the drug was observed in vitro from both kinds of systems. The swelling properties of the polymer seemed to be the main parameter affecting the drug release profile from both tablets and hydrogels at the pH value of mouth. In vivo buccal application of both the systems allowed to obtain a prolonged release of DSP, as compared with a glycerine solution of the drug. From the in vitro swelling studies and in vivo test, the 2:1 CH-DSP solid dispersion in particular can be designated for further investigation.