Human and rat liver UDP-glucuronosyltransferases are targets of ketoprofen acylglucuronide.

Acylglucuronides formed from carboxylic acids by UDP-glucuronosyltransferases (UGTs) are electrophilic metabolites able to covalently bind proteins. In this study, we demonstrate the reactivity of the acylglucuronide from the nonsteroidal anti-inflammatory drug, ketoprofen, toward human and rat liver UGTs. Ketoprofen acylglucuronide irreversibly inhibited the glucuronidation of 1-naphthol and 2-naphthol catalyzed by human liver microsomes or by the recombinant rat liver isoform, UGT2B1, which is the main isoform involved in the glucuronidation of the drug. A decrease of about 35% in the glucuronidation of 2-naphthol was observed when ketoprofen acylglucuronide was produced in situ in cultured V79 cells expressing UGT2B1. Inhibition was always associated with the formation of microsomal protein-ketoprofen adducts. The presence of these covalent adducts within the endoplasmic reticulum of cells expressing UGT2B1 was demonstrated following addition of ketoprofen to culture medium by immunofluorescence microscopy with antiketoprofen antibodies. Immunoblots of liver microsomes incubated with ketoprofen acylglucuronide and probed with antiketoprofen antibodies revealed the presence of several protein adducts; among those was a major immunoreactive protein at 56 kDa, in the range of the apparent molecular mass of UGTs. The adduct formation partially prevented the photoincorporation of the UDP-glucuronic acid (UDP-GlcUA) analog, [beta-32P]5N3UDP-GlcUA, on the UGTs, suggesting that ketoprofen glucuronide covalently reacted with the UDP-GlcUA binding domain. Finally, UGT purification from rat liver microsomes incubated with ketoprofen glucuronide led to the isolation of UGT adducts recognized by both anti-UGT and antiketoprofen antibodies, providing strong evidence that UGTs are targets of this metabolite.     

Protein-loaded poly(epsilon-caprolactone) microparticles. I. Optimization of the preparation by (water-in-oil)-in water emulsion solvent evaporation.

The aim of this work was to optimize protein entrapment in pure poly(epsilon-caprolactone) (PCL) microparticles (MP) using the (water-in-oil)-in water solvent evaporation technique and bovine serum albumin (BSA) as drug model. Therefore, the preparative variables such as polymer solvent, protein/polymer ratio, polymer molecular weight, internal aqueous/organic phases ratio, organic/external aqueous phase ratio, and nature of the emulsifier were evaluated on microparticle characteristics such as BSA entrapment, entrapment efficiency, size and morphology. The in vitro release profiles of BSA from such MP in two different media with or without sodium dodecyl sulphate (SDS) were investigated. In optimum conditions, smooth and spherical pure PCL MP with high encapsulation efficiency (50.29 +/- 5.01%) were prepared. The release profiles of BSA in the release media were significantly different and faster in the presence of SDS. Moreover, they exhibited a relatively low burst effect after 24h (<30%) followed by a continuous release over 28 days. Due to PCL's numerous desirable characteristics, such MP could be an exciting alternative for the controlled release of proteinaceous compounds.     

Existence of different subtypes of nicotinic acetylcholine receptors in the rat habenulo-interpeduncular system.

Neuronal nicotinic ACh receptors (nAChRs) are present in the rat medial habenula (MHB) and interpeduncular nucleus (IPN), two brain regions connected through the fasciculus retroflexus (FR). The goal of the present study was to compare the electrophysiological and pharmacological characteristics of nAChRs located at pre- and postsynaptic sites within the MHB-IPN system. nAChRs located on the soma of IPN neurons were studied using patch-clamp techniques and a preparation of acutely isolated neurons. Whole-cell currents evoked by Ach and nicotine showed an intense rectification at positive membrane potentials. nAChR channels were relatively nonselective for cations, had a unitary conductance of 35 pS, and were activated by several nicotinic agonists with the following rank order: cytisine greater than ACh greater than nicotine greater than dimethylphenylpiperazinium (DMPP). They were blocked by mecamylamine, hexamethonium, curare, and dihydro-beta-erythroidine (DHBE), but were insensitive to alpha-bungarotoxin and neuronal bungarotoxin. In contrast, nAChRs recorded on the soma of MHB neurons under equivalent experimental conditions exhibited different characteristics for single-channel conductance and agonist and antagonist sensitivity. The pharmacological properties of presynaptic nAChRs in the IPN were analyzed in a rat brain slice preparation. Stimulation of the FR produced a presynaptic afferent volley recorded in the rostral subnucleus of the IPN. Nicotinic agonists decreased the amplitude of the afferent volley with different efficacies: nicotine greater than cytisine greater than ACh greater than DMPP. The action of nicotine was insensitive to alpha-bungarotoxin and to neuronal bungarotoxin, but was blocked by mecamylamine, hexamethonium, curare, and DHBE, with IC50 values different from those reported for IPN postsynaptic nAChRs. This study thus demonstrates the functional diversity of nAChRs in the rat CNS.     

Complications after radical retropubic prostatectomy in the medicare population

OBJECTIVES: Radical prostatectomy is the standard of care for the treatment of clinically localized prostate cancer in the appropriate patient. However, the morbidity associated with this procedure remains controversial, since complications from centers of excellence are low but nationwide surveys have reported a much higher risk of complications. This study reports the complication rates after radical retropubic prostatectomy (RRP) for men in the Medicare population. METHODS: All men in the Medicare population who underwent RRP in 1991 were identified. All inpatient, outpatient, and physician (Part B) Medicare claims for these men for 1991 to 1993 were then analyzed to determine outcomes. Procedures performed for complications resulting from RRP were recorded, as were the diagnosis codes that may have heralded a complication after RRP. RESULTS: In 1991, 25,651 men in the Medicare population underwent RRP. The mean age of these men was 70.5 years. Procedures for the relief of bladder outlet obstruction or urethral strictures after RRP occurred in 19.5% of these men. A penile prosthesis was implanted in 718 men (2.8%) after prostatectomy, and 593 men (2.3%) had an artificial urinary sphincter placed after prostatectomy. A diagnosis of urinary incontinence was reported in 5573 men (21.7%) after radical prostatectomy, but only 2025 of these men (7.9%) continued to carry this diagnosis more than 1 year after prostatectomy. A diagnosis of erectile dysfunction was reported in 5510 men (21.5%) after radical prostatectomy, but only 3276 of these men (12.8%) continued to carry this diagnosis more than 1 year after surgery. CONCLUSIONS: A review of a large, nationwide, heterogenous cohort of men revealed a morbidity rate that is slightly higher than that reported by major centers that perform large numbers of radical retropubic prostatectomies but is lower than complication rates obtained by patient surveys. The limitations of claim information in determining patient outcomes, however, must be considered when evaluating these data.