Aminopeptidase P activity in rat organs and human serum

The substrate Lys(epsilon-Dnp)-Pro-Pro-NH-CH2-CH2-NH-ABz in which the fluorescent 2-aminobenzoyl (ABz) group (lambda ex = 320, lambda em = 410 nm) is intramolecularly quenched by the 2,4-dinitrophenyl (Dnp) chromophore was synthesized and used for the development of a sensitive assay for aminopeptidase P (EC 3.4.11.9). The emission of the intact compound was 160 times less than that of an equimolar concentration of Pro-Pro-NH-CH2-CH2-NH-ABz under the same conditions. The efficient resonance energy transfer permits an increased assay sensitivity as compared to the previously reported Phe(p-NO2)-Pro-Pro-NH-CH2-CH2-NH-ABz in which the p-nitrophenylalanyl [Phe(p-NO2)] residue caused only a 3.4-fold collisonal quenching. The kinetic constants Km were determined as 100 +/- 3.0 and 38 +/- 1.0 microM (mean of four experiments) for the human serum and the rat-lung enzymes, respectively. Both enzymes were inhibited by metal chelating agents and were not affected by 2.8 microM diisopropyl fluorophosphate. The mean activity in the sera of 53 healthy adults was 37.4 +/- 2.7 (standard error) with a standard deviation of 19.2 units/ml of serum. Only 10 microliters of serum was required for a reliable assay of the enzyme. The specific activity in rat-organ extracts was determined. High aminopeptidase P activity was observed in the testis, lung, kidney, and ovary and lower activity was observed in the serum.     

Investigation of the Physicochemical and Physicomechanical Properties of a Novel Intravaginal Bioadhesive Polymeric Device in the Pig Model

The purpose of this study was to develop and evaluate the bioadhesivity, in vitro drug release, and permeation of an intravaginal bioadhesive polymeric device (IBPD) loaded with 3′-azido-3′-deoxythymidine (AZT) and polystyrene sulfonate (PSS). Modified polyamide 6,10, poly(lactic-coglycolic acid), polyacrylic acid, polyvinyl alcohol, and ethylcellulose were blended with model drugs AZT and PSS as well as radio-opaque barium sulfate (BaSO4) and then compressed into caplet devices on a tableting press. One set of devices was coated with 2% w/v pentaerythritol polyacrylic acid (APE-PAA) while another remained uncoated. Thermal analysis was performed on the constituent polymers as well the IBPD. The changes in micro-environmental pH within the simulated human vaginal fluid due to the presence of the IBPD were assessed over a period of 30 days. Textural profile analysis indicated that the bioadhesivity of the APE-PAA-coated devices (3.699 ± 0.464 N; 0.0098 ± 0.0004 J) was higher than that of the uncoated devices (1.198 ± 0.150 N; 0.0019 ± 0.0001 J). In addition, BaSO4-facilitated X-ray imaging revealed that the IBPD adhered to pig vaginal tissue over the experimental period of 30 days. Controlled drug release kinetics was obtained over 72 days. During a 24-h permeation study, an increase in drug flux for both AZT (0.84 mg cm⁻² h⁻¹) and PSS (0.72 mg cm⁻² h⁻¹) was realized up to 12 h and thereafter a steady-state was achieved. The diffusion and dissolution dynamics were mechanistically deduced based on a chemometric and molecular structure modeling approach. Overall, results suggested that the IBPD may be sufficiently bioadhesive with desirable physicochemical and physicomechanical stability for use as a prolonged intravaginal drug delivery device.     

Mycobacterium tuberculosis curli pili (MTP) is associated with significant host metabolic pathways in an A549 epithelial cell infection model and contributes to the pathogenicity of Mycobacterium tuberculosis

Metabolomics - Diabetes mellitus is a serious metabolic disorder causing multiple organ damage in human. However, the lipidomic profiles in different organs and their associations are rarely...     

The Influence of the Early Rearing Environment on the Development of Paternal Care in African Striped Mice

In some biparental mammals, paternal care is important for offspring development and survival. We investigated the influence of the early post‐natal environment on the development of paternal care in the naturally paternal desert‐dwelling African striped mouse (Rhabdomys pumilio). Our aim was to establish whether the expression of paternal care in adult sons is influenced by their experience of paternal care. Offspring were raised in one of three conditions: both parents raised young; mothers raised young alone; and mothers raised young alone but were separated from the father with a barrier. The paternal care behaviour of sons was investigated when they were adults. Contrary to expectations, adult sons raised by the mother alone displayed greater levels of huddling behaviour of their own pups compared to sons raised by both parents. This response appears to be influenced by the early mother–son relationship, because mothers raising pups alone compensated for the absence of fathers by increasing the time spent with pups compared to mothers raising pups with fathers. The mechanisms underpinning the development of paternal care are not apparent in our study. Nonetheless, the development of paternal care is condition‐dependent in male striped mice, indicating that the potential for greater levels of care occurs in the absence of the father and concomitant compensation of maternal care during early development.