Evidence for the involvement of protein kinase C isoforms in alpha-1 adrenergic activation of phospholipase A2 in FRTL-5 thyroid cells

BACKGROUND: FRTL-5 thyroid cells are a cell line extensively used for the investigation of thyroid functions. Activation of alpha-1 adrenergic receptors stimulates both arachidonic acid (AA) release and cytosolic Ca2+ increase in this cell line. Cytosolic Ca2+ and arachidonic acid are known to be important second messengers regulating a variety of thyroid functions. The generation of these messengers is regulated primarily by two different types of phospholipases, phospholipase C (PLC) and phospholipase A2 (PLA2). METHODS: Norepinephrine (NE, 10 mumol/L) was used as an alpha-1 adrenergic activator, and cytosolic-free Ca2+ concentration ([Ca2+]i) was determined using the fluorescent dye indo-1. Arachidonic acid release was measured as an indicator of PLA2 activation, and protein kinase C (PKC) activity determination and isoforms identification were performed using commercial kits. RESULTS: Norepinephrine increased [Ca2+]i and AA release. Prevention of NE-induced cytosolic Ca2+ influx, either by removal of extracellular Ca2+ or by use of Ca2+ channel blockers, NiCl2 or CoCl2, inhibited AA generation entirely. Inhibition of NE-induced increase in [Ca2+]i by the Ca2+ chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), also significantly suppressed NE-induced AA release. Inhibition of PKC activity by PKC inhibitors (H-7 or staurosporine) or downregulation induced by prolonged treatment with phorbol 12-myristate 13-acetate (PMA) or thyleametoxin (TX) significantly blocked the NE-induced AA release, which indicates PKC is involved in mediating NE-induced AA release. Protein kinase C activity measurement indicated that NE induced an activation of PKC in 5 minutes. To further characterize the role of PKC or Ca2+ in regulation of AA release, we identified PKC isoforms by immunoblotting with specific antibodies against 8 different Protein kinase C isoforms. PKC-alpha, -beta I, -beta II, -gamma, delta, -epsilon, -zeta, and -eta isoforms were identified. Norepinephrine induced translocation of PKC-alpha, -beta I, -beta II, -gamma, -delta, and -epsilon isoforms but not -zeta and -eta from cytosol to membrane. Chelation of intracellular Ca2+, prevention of Ca2+ influx, or prolonged treatment with thymeleatoxin (TX) completely blocked the NE-induced translocation of PKC-alpha. CONCLUSIONS: These results, taken together with data obtained from AA experiments, suggest that PKC plays a critical role in alpha-1 adrenergic receptor mediated PLA2 activation and subsequent AA release. Extracellular Ca2+ influx is a prerequisite for both PKC-alpha translocation and AA release. Whether Ca2+ acts directly upon the PLA2, or via PKC-alpha, to regulate AA generation is an intriguing question that remains to be clarified.     

New advances in the treatment of infertility in women with ovarian failure

Ovarian failure is heterogeneous in etiology and may occur at various points in a woman's life. As such, it may interfere with fertility. Clinical presentation ranges from complete cessation of menses to oligomenorrhea to the continuation of menses with elevated gonadotropins. Various therapies have been used in an attempt to induce fertility, including sex steroids and gonadotropin-releasing hormone agonists to suppress circulating gonadotropin alone or in combination with estrogen or gonadotropin-releasing hormone agonists to induce ovulation. Corticosteroids are also used to overcome autoimmunity. Randomized therapeutic trials are rare and fail to demonstrate any significant improvement in ovulation and pregnancy rates. Donor oocytes have demonstrated high success rates and have proven to be useful in patients with both premature ovarian failure and natural menopause. Pregnancies have been initiated and maintained in women through 60 years of age. Thus, for those accepting of the technique, oocyte donation appears to be the treatment of choice for hypergonadotropic hypogonadism.     

A simple and inexpensive method for the identification of Staphylococcus epidermidis and Staphylococcus hominis

Eight hundred and ninety-two strains of Staphylococcus species were identified by means of desferrioxamine susceptibility and fermentation results of three carbohydrates, with the API Staph system (bioMérieux, France) as reference method. No identification could be obtained for 34 strains with API Staph. Of the remaining 858 strains, identical identification was obtained with 842 (98.1%). All 707 strains identified as Staphylococcus epidermidis or Staphylococcus hominis by the API Staph system were found to be desferrioxamine susceptible, and all but 5 (3.3%) of 151 strains identified as other staphylococcal species were found to be resistant, yielding an identification correlation of 99.4% for desferrioxamine. The five additional strains which were susceptible to desferrioxamine were identified as Staphylococcus capitis (2 strains), Staphylococcus lugdunensis (2 strains), and Staphylococcus warneri (1 strain) by API Staph, and as Staphylococcus epidermidis (1 strain), Staphylococcus hominis (3 strains), and one other staphylococcal species by the experimental system.     

Generalized Gabor expansions of discrete-time signals in l2(Z) via biorthogonal-like sequences

In this paper, a biorthogonal-like sequences (BLS) theory and its application to the generalized Gabor expansions (equivalently, the generalized short-time Fourier transform/filterbank summation) are presented. A pair of BLS's are defined to be two sequences satisfying a biorthogonal-like condition (BLC), which is a moment equation and equivalent to a linear difference equation. We show that two collections in a Hilbert space generated by a pair of BLS's in the joint time-frequency domain are complete, either can be used as an analysis filter, and the other can be used as a synthesis filter for a generalized Gabor expansion of discrete-time signals. A sufficient and necessary condition on the existence of BLS's based on the moment equation is presented, which is simpler to use than frame theory. Given a filter generating a frame, its BLS's also generate frames. The dual frame is one of them. Given a FIR analysis/synthesis filter, there is a FIR synthesis/analysis filter if BLS's exist. The algorithm to compute FIR analysis and synthesis filters based on the linear difference equation is presented in this paper, which is simpler than frame operator     

An analysis of contemporary printed wiring board manufacturing environment in the USA

This article presents a comparative analysis of contemporary printed wiring assembly (PWA) batch manufacturing systems employing surface mount technology (SMT), This analysis is accomplished by reviewing a typical case study of PWA manufacturing system in the USA. A previously developed model is then applied to the system to predict the cost and performance in the production of typical PWA designs. Various modifications to the system are then proposed and evaluated. From the case study, conclusions concerning optimum manufacturing system configuration for this industry can be drawn and are presented.     

Off-Optimum Cure of Aerospace Epoxy Adhesives

Four epoxy film adhesives used in aircraft manufacture and repair have been examined to establish the effect of deviation from the cure cycle specified by the manufacturer. In addition to the variation of the cure cycle, two surface preparations of the aluminium adherends (chromic acid etch or grit blast followed by silane treatment) were evaluated. Thermal analysis was used to examine the cure envelope of the adhesive, and its extent of cure and glass transition temperature. The adhesive properties were assessed by shear strength (in both single lap joints and in Iosipescu configuration), durability (Boeing wedge test) and chemical resistance to selected aggressive fluids. The sensitivity of the performance of a particular adhesive to offoptimum cure conditions depends on its composition and needs to be determined, not predicted.     

Robot manipulator kinematic compensation using a generalized jacobian formulation

The kinematic error compensation of robot manipulators is at present being attempted by improving the precision of the nominal robot kinematic parameters. This paper addresses the problem of kinematic compensation using a new mathematical joint model proposed to account for shortcomings in existing methods. The corrected manipulator transformation is formulated in terms of “generalized Jacobians”: relating differential errors at the joints to the differential change in the manipulator transformation. The details of application are discussed for a particular industrial manipulator.     

Post-compaction heat-treatment response of dynamically-compacted Inconel 718 powder

Dynamically-compacted Inconel 718 powder has been heat treated in order to examine the evolution of microstructural recovery and hardness, recrystallization and grain coarsening, and interparticle-adhesion and fracture response. Following dynamic compaction the compacted powders are imperfectly bonded and the material is fairly brittle; the shock wave has caused significant hardening; local microstructures and properties are variable from particle surface to interior. Following annealing at 900 to 1000° C, virtually complete recrystallization occurs giving rise to a material which is softened and has a fine-scale microstructure. Little improvement in fracture response occurs, however, because the oxidized prior-particle surfaces do not weld together. Shock-wave consolidation offers the possibility of producing monolithic, microstructurally-fine materials, providing suitable post-consolidation thermo-mechanical processes are developed to overcome the limited bonding problem.