Effect of Nitric Oxide Synthase Inhibition on Fos Expression in the Hypothalamus of Female Rats Following Central Oxytocin and Systemic Urethane Administration

Three experiments were carried out to investigate the pattern of neuronal activation induced by central oxytocin administration and its modulation by nitric oxide (NO). First, we compared the induction of Fos-like immunoreactivity (lir) in the supraoptic (SON) and paraventricular (PVN) nuclei and medial preoptic area (MPOA) after central oxytocin administration between nonlactating and lactating rats. Next, we investigated whether NO modulated Fos induction following central oxytocin administration using a nitric oxide synthase (NOS) inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME). Finally, to determine whether the effects of NOS inhibition on Fos induction would generalize to stimuli other than oxytocin, we compared Fos-lir in the SON and PVN of lactating and nonlactating rats following L-NAME and urethane administration. In the first two experiments, oxytocin (50 ng in 2 microl) or vehicle was administered into the third ventricle. L-NAME (50 mg/kg) was given by an intraperitoneal (i.p.) injection 30 min before oxytocin administration (experiment 2) or an i.p. injection of urethane (1.4 g/kg) (experiment 3). In all experiments, lactating rats were tested on day 12 or 13 postpartum and nonlactating females at least 11 days after surgery or the start of the experiment. Central oxytocin infusion induced Fos expression in the SON and PVN in lactating and nonlactating rats and in the MPOA and bed nucleus of the stria terminalis in lactating rats. Overall, lactating rats that received L-NAME and oxytocin had a greater number of cells showing Fos-lir in both the SON and PVN. Conversely, L-NAME administration reduced Fos-lir in the SON and PVN in oxytocin-stimulated nonlactating rats. In urethane-treated rats, L-NAME administration did not change Fos-lir in lactating rats but reduced Fos-lir in nonlactating rats. These data suggest that the role of NO in modulating the activity of neurones in discrete nuclei in the hypothalamus varies across reproductive state and with the stimulus presented.     

两种不同膀胱测压方法对不同年龄大鼠尿动力测定的影响

目的比较目前应用的大鼠在乌拉坦麻醉下经尿道置双根导管膀胱测压与置单根导管连接三通管膀胱测压的尿动力学指标差异及两种方法的优缺点。方法取6、12月龄的♀成年大鼠各11只,乌拉坦腹腔麻醉,尿道内置入2根3F自制测压导管,分别与尿动力仪的压力传感器及微量注射泵连接,同时由肛门置入直肠测压气囊管与腹压传感器连接。应用尿动力仪测定大鼠充盈期膀胱压力变化及腹压漏尿点压。5 d后同样经尿道插入单根3F膀胱测压导管,导管接上三通,三通一端与微量灌注泵相接,另一端接尿动力仪的膀胱压力传感器,其余操作相同。结果 12月龄大鼠的与6月龄性大鼠比较,用双管法测出BLPP、MVP差异有显著性(P<0.05),而用三通法则两者差异无显著性,且三通法测出两组动物的各指标值均比双管法的数值高(P<0.01)。结论两种大鼠膀胱测压方法对尿动力的某些指标差异有显著性,两种方法各有优劣。     

Role of Syzygium cumini seed extract in the chemoprevention of in vivo genomic damage and oxidative stress

Ethanopharmacological relevance

The seeds of Syzygium cumini, Skeels (Jamun) are extensively used in India for treatment of diabetes and other ailments.

Aim of the study

The aim of this work was to assess the role of Jamun seed extract (JSE) as a chemoprotective agent against in vivo oxidative stress and genomic damage.

Materials and methods

Experiments were carried out to evaluate in vitro protective effects of JSE against hydroxyl radical induced damage in pBR322 DNA, and in vivo genomic damage and oxidative stress in mice which received JSE orally for 5 days before exposure to genotoxic carcinogens urethane (URE) and 7,12-dimethyl benz(a)anthracene (DMBA).

Results

Aqueous and ethanolic extracts of JSE showed significant protective effects against hydroxyl radical induced strand breaks in pBR322 DNA. The in vivo experiments with aqueous JSE showed significant protective effects against chromosomal damage induced by the genotoxic carcinogens URE and DMBA. Biochemical assays registered significant inhibition of hepatic lipid peroxidation and increase in GSH level and activity of GST, SOD and CAT.

Conclusion

Our findings suggest that JSE can possibly play an important role as a chemopreventive agent against oxidative stress and genomic damage.     

Phosphorescent nanoparticles for quantitative measurements of oxygen profiles in vitro and in vivo

We present the development and characterization of nanoparticles loaded with a custom phosphor; we exploit these nanoparticles to perform quantitative measurements of the concentration of oxygen within three-dimensional (3-D) tissue cultures in vitro and blood vessels in vivo. We synthesized a customized ruthenium (Ru)-phosphor and incorporated it into polymeric nanoparticles via self-assembly. We demonstrate that the encapsulated phosphor is non-toxic with and without illumination. We evaluated two distinct modes of employing the phosphorescent nanoparticles for the measurement of concentrations of oxygen: 1) in vitro, in a 3-D microfluidic tumor model via ratiometric measurements of intensity with an oxygen-insensitive fluorophore as a reference, and 2) in vivo, in mouse vasculature using measurements of phosphorescence lifetime. With both methods, we demonstrated micrometer-scale resolution and absolute calibration to the dissolved oxygen concentration. Based on the ease and customizability of the synthesis of the nanoparticles and the flexibility of their application, these oxygen-sensing polymeric nanoparticles will find a natural home in a range of biological applications, benefiting studies of physiological as well as pathological processes in which oxygen availability and concentration play a critical role.     

Occupational methacrylate and acrylate allergy – cross‐reactions and possible screening allergens

Background. Acrylic resin monomers, especially acrylates and methacrylates, are important occupational allergens. Aims. To analyse patterns of concomitant patch test reactions to acrylic monomers in relation to exposure, and to suggest possible screening allergens. Patients/methods. We reviewed the patch test files for the years 1994–2009 at the Finnish Institute of Occupational Health for allergic reactions to acrylic monomers, and analysed the clinical records of sensitized patients. Results. In a group of 66 patients allergic to an acrylic monomer, the most commonly positive allergens were three methacrylates, namely ethyleneglycol dimethacrylate (EGDMA), 2‐hydroxyethyl methacrylate (2‐HEMA) and 2‐hydroxypropyl methacrylate (2‐HPMA), and an acrylate, namely diethyleneglycol diacrylate (DEGDA). The patterns of concomitant reactions imply that exposure to methacrylates may induce cross‐reactivity to acrylates, whereas exposure to acrylates usually does not lead to cross‐allergy to methacrylates. Screening for triethyleneglycol diacrylate (TREGDA) in the baseline series was found to be useful, as 3 of 8 patients with diagnosed occupational acrylate allergy might have been missed without the screening. Conclusions. A short screening series of four allergens, EGDMA, DEGDA, 2‐HPMA and pentaerythritol triacrylate (PETA), would have screened 93% of our 66 patients; each of the remaining 5 patients reacted to different acrylic monomer(s).     

Functional connectivity between the thalamus and postsubiculum: Analysis of evoked responses elicited by stimulation of the laterodorsal thalamic nucleus in anesthetized rats

The laterodorsal nucleus (LDN) of the thalamus provides a prominent afferent projection to the postsubiculum (dorsal presubiculum). To characterize synaptic transmission in this pathway, we placed stimulating electrodes in the LDN and recorded fEPSPs elicited in the postsubiculum of urethane‐anesthetized rats. LDN stimulation elicited a source‐sink dipole between the deep and superficial layers of the postsubiculum, respectively, consistent with anatomical evidence for the termination of thalamic afferents in the superficial layers of the structure, and the existence of deep layer neurons with apical dendrites extending into these layers. Postsubicular fEPSPs were typically 0.5–1.0 mV in amplitude, with a peak latency of approximately 6 ms. Consistent with anatomical observations, the short onset latency of fEPSPs elicited by LDN stimulation, and their ability to follow a 60‐Hz train of stimulation, indicate that the projection is monosynaptic. Paired‐pulse stimulation revealed pronounced paired‐pulse depression that was maximal at 100 ms, suggesting that initial release probabilities are high at LDN‐postsubiculum synapses, in common with many neocortical pathways. A conventional tetanus protocol that yields LTP in hippocampal pathways had no effect on postsubicular fEPSPs, but long‐term depression could be induced by 60‐Hz stimulation. Drug infusion studies revealed that synaptic transmission in the LDN‐postsubiculum projection is predominantly AMPA‐receptor mediated. Rats were implanted with indwelling infusion cannulae targeting the postsubiculum, and, after a recovery period, were anaesthetized withurethane, and implanted with stimulating and recording electrodes. Infusion of CNQX almost completely abolished postsubicular fEPSPs, whereas D‐AP5 had little effect. However, 60‐Hz LTD was blocked by D‐AP5 infusion, revealing that this form of synaptic plasticity is NMDA‐receptor dependent. © 2013 Wiley Periodicals, Inc.     

Poly(ester urethane) with Varying Polyester Chain Length: Polymorphism and Shape‐Memory Behavior

The swelling, viscoelastic, and mechanical behavior of phase‐segregated poly(ester urethane) (PEU) block copolymers, composed of 4,4′‐methylenediphenyl diisocyanate, 1,4‐butanediol as a chain extender, and crystallizable poly(1,4‐butylene adipate) (PBA) with molecular weights between 1330 and 4120 g mol^?1, are investigated. Wide‐angle X‐ray scattering (WAXS) is employed to study the overall PEU crystallinity, which increases from 8.6 to 13.6% at higher PBA contents. The existence of two crystalline, polymorphic PBA phases, a thermodynamically stable α phase and a metastable β phase, is confirmed by further WAXS measurements. Calorimetric and thermomechanical investigations give evidence for controllable PBA polymorphic behavior. The crystallization conditions, like the cooling rate, affect the emerging polymorphic mixture, whereas the storage conditions either promote or inhibit the polymorphic (β to α) transition. The introduced concepts represent a new approach for gaining control over programmable thermo­responsiveness, which may be transferable to other shape‐memory polymers with polymorphic switching segments.

     

盐酸含量对光固化聚氨酯丙烯酸酯/SiO2杂化材料结构和性能的影响

由正硅酸乙酯水解制得的SiO2溶胶，在以γ—甲基丙烯酰氧丙基三甲氧基硅烷(TMSPM)为偶联剂的体系中，经溶胶-凝胶法制备了透明的光固化聚氨酯丙烯酸酯杂化材料[(PUA—TMSPM)／SiO2]。研究了盐酸浓度对(PUA-TMSPM)／SiO2结构与性能的影响。结果表明：随着pH值减小，硅溶胶体系和(PUA-TM-SPM)／SiO2杂化体系的热稳定性增大；盐酸摩尔分数XHCl的增加使(PUA-TMSPM)／SiO2光固化膜表面的两相界面结合更紧密，涂层变得更致密，并导致膜的硬度和耐磨性提高。     

热塑性塑料聚氨酯人造橡胶在医用材料领域的潜能

本文对热塑性塑料聚氨酯人造橡胶材料的成分和聚合体结构进行了阐述，并且对该材料物理特性和化学特性进行分析，论述了在医用材料领域中广泛的应用前景。