Effects of microencapsulated Enterococcus fecalis CG1.0007 on growth performance, antioxidation activity, and intestinal microbiota in broiler chickens

We performed a series of trials to assess the effect of dietary supplementation with microencapsulated Enterococcus fecalis CG1.0007 on growth performance, antioxidation activity, and intestinal microbiota in Arbor Acres broiler chickens ("broilers"). A total of 150 1-d-old broilers were assigned randomly to 5 feeding treatments (a control group fed the basal diet, 3 groups fed the basal diet plus various concentrations of microencapsulated CG1.0007, and 1 group fed the basal diet plus an antibiotic). Changes in important genera of intestinal bacteria were studied using 16S rRNA gene-based PCR-denaturing gradient gel electrophoresis (DGGE) profiling and real-time quantitative PCR analysis of fecal samples. During the course of the 42-d experimental period, ADG of the birds fed the high and intermediate concentrations of microcapsules were significantly greater (9.90 and 9.50%, respectively) and the ratios of feed to gain fed were significantly lower (4.40 and 4.00%, respectively) compared with the control group. The total antioxidant capacity and the content of malondialdehyde and superoxide dismutase in the microcapsule-treated groups showed significant changes in terms of antioxidation. The numbers of Lactobacillus and Bifidobacterium were significantly greater in the microcapsule-treated groups than in the control group. Cluster analysis indicated that the DGGE bacterial profiles were related to the feeding treatments and revealing the diversity and richness of the intestinal microbiota associated with supplementation of microcapsules. In summary, our results indicate that dietary addition of microencapsulated E. fecalis CG1.0007 enhanced the growth performance of the broilers and improved their health.

Solid-phase photocatalytic degradation of polyethylene-goethite composite film under UV-light irradiation

A novel photodegradable polyethylene-goethite (PE-goethite) composite film was prepared by embedding the goethite into the commercial polyethylene. The degradation of PE-goethite composite films was investigated under ultraviolet light irradiation. The photodegradation activity of the PE plastic was determined by monitoring its weight loss, scanning electron microscopic (SEM) analysis and FT-IR spectroscopy. The weight of PE-goethite (1 wt%) sample steadily decreased and led to the total 16% reduction in 300 h under UV-light intensity for 1 mW/cm(2). Through SEM observation there were some cavities around the goethite powder in the composite films, but there were few changes except some surface chalking phenomenon in pure PE film. The degradation rate could be controlled by changing the concentration of goethite particles in PE plastic. The degradation of composite plastic initiated on PE-goethite interface and then extended into polymer matrix induced by the diffusion of the reactive oxygen species generated on goethite particle surface. The photocatalytic degradation mechanism of the composite films was briefly discussed.

Specific immune milk production of cows implanted with antigen-release devices

A new antigen-release device (ARD) that can be implanted to enhance the titer of specific IgG and concentration of total IgG in milk of lactating cows was evaluated. An immunostimulating complex-based vaccine in the core of the ARD was made from the adjuvant Quil A and type XIII lipase from Pseudomonas spp. with a polylactide acid capsule that was used to control antigen release. Forty lactating Holstein dairy cows were divided into 2 groups (n = 20). All cows in the test group were implanted in the right iliac lymph node with 3 types of ARD at the same time, which were designed to release antigens on different days. The other group was used as a control with no implantation. The 3 ARD were designed to release the antigen on d 0, 14, and 28 after implantation. Specific IgG titers in whey and serum were measured by indirect ELISA, and total IgG concentrations were measured using sandwich ELISA. The results indicated that ARD implantation brought no negative effects on the health status, production performance of cows, and caused neither subclinical nor acute mastitis. The levels of specific IgG in serum (200,000 +/- 45,000 vs. 1,200 +/- 360) and whey (41,000 +/- 6,000 vs. 820 +/- 210) increased in the cows implanted with ARD. Specific IgG in whey was increased after 9 d. The dynamics of specific IgG titer demonstrated a pattern with the release of the antigen from 3 types of ARD. The average ELISA titer of test group in whey was 41,000 +/- 6,000, which suggested high efficiency of immune milk production caused by the ARD implantation. For total IgG in milk, greater concentration in the test compared with the control cows occurred from 11 to 20 d following implantation. The IgG mass was consistent with the dynamics of specific IgG titer and was higher from 15 to 30 d between test and control group (7.89 +/- 1.34 vs. 6.48 +/- 1.17 g). In conclusion, ARD implantation was effective in improving specific antibody concentration in serum and whey. Furthermore, the whey:serum ratio of specific IgG titer, the milk:serum ratio of total IgG concentration and total IgG mass in milk suggested that a transiently upregulated IgG transfer occurred after ARD implantation.

Localization and gestation-dependent pattern of corticotrophin-releasing factor receptor subtypes in ovine fetal distal colon

Meconium passage is frequently observed in association with feto-maternal stress factors such as hypoxia and infection, but the triggering mechanism is unknown. We hypothesize that differential regulation of corticotrophin-releasing factor (CRF) receptors during gestation play an important role in determining the susceptibilities of the fetus to stress-induced in utero meconium passage at term. We examined the innervation patterns of CRF-receptor type 1 (CRF-R1), a stimulator of gastrointestinal motility and CRF-receptor type II (CRF-R2), an inhibitor of gastrointestinal motility in ovine fetal distal colonic segments from very preterm to term gestation. Both CRF-R1 and CRF-R2 receptors were present in muscularis mucosa as well as in longitudinal and circular smooth muscle layers in fetal distal colonic segments at all gestational ages. Quantitative image analysis indicated a 42% increase in CRF-R1 receptor immunoreactivity in muscularis mucosa and a 30% in longitudinal smooth muscle layers from very preterm to term. In contrast, CRF-R2 receptor immunoreactivity in muscularis mucosa as well as in longitudinal and circular smooth muscle layers decreased by 38%, 55% and 51%, respectively, at term. The percentage of enteric ganglia and the number of enteric neurons expressing CRF-R1 receptors were high at term. Western blot analysis identified 235 and 50 kDa molecular species of CRF-R1 receptors and 37 and 28 kDa molecular species of CRF-R2 receptors. In summary, we speculate that downregulation of CRF-R2 receptor abundance with concurrent increases in CRF-R1 receptor levels in myenteric-smooth muscle unit with advancing gestation sensitizes the colonic motility responses to stressors.

The effect of implanting an antigen release device on lactoferrin concentration in serum and milk

The objective of this study was to evaluate the effect of implanting an Antigen Release Devices (ARD) into dairy cows during the lactation cycle to induce an immune response. Subsequently, the concentrations of lactoferrin in serum and milk were measured. Forty healthy adult Chinese Holstein cows were divided into two equal groups: a test group and a control group. Animals in the test group received ARD implants, whereas the control group animals were not treated. An even spread across the two groups was maintained with animal selection based on parity, the lactation days and milk yields. The concentrations of lactoferrin in the serum and milk of all forty animals were measured using an Enzyme-Linked Immunosorbent Assay (ELISA). The results show that the implantation of an ARD did not significantly increase the concentration of lactoferrin in the serum and milk throughout the whole experiment period except on two occasions. The levels of lactoferrin in the milk and serum significantly increased on day 7 and on day 11 after implantation (p<0.05). There was a strong correlation between milk lactoferrin and serum lactoferrin (r=0.564, P<0.01). Three separate ARDs were used releasing its antigen load on day 0, 14 and 28 to induce a primary, secondary and tertiary response respectively. As the significant increases in the lactoferrin levels were only observed after the first ARD release, the effects of lactoferrin appears to be associated with the early phase of the immune response, consistent with its role in the host's innate defense system.

Musclin Inhibits Insulin Activation of Akt/Protein Kinase B in Rat Skeletal Muscle

Musclin is a muscle-derived secretory peptide that induces insulin resistance in vitro We studied the effect of musclin (0.5 μg/ml) on insulin-stimulated glucose uptake in rat skeletal muscles and also the effect of rosiglitazone (0.4 μg/ml). Pre-incubation of muscles with musclin resulted in decreased insulin-stimulated glucose uptake. Musclin also reduced expression of peroxisome proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα) mRNAs, although expression of glucose transporter 4 mRNA was unaltered. Rosiglitazone attenuated the effects of musclin on glucose uptake and PPARγ and LXRα mRNA expression. Western blotting demonstrated that activation of protein kinase B (Akt/PKB) in the insulin-signalling cascade was decreased by musclin but corrected by rosiglitazone. These findings suggest that musclin-induced impairment of insulin-stimulated glucose uptake in skeletal muscle is related to Akt/PKB inhibition and might be modulated by PPARγ/LXRα.

Factors affecting the lactoferrin concentration in bovine milk

Lactoferrin (LF) concentrations in the milk with different levels of the somatic cell count score were examined using an ELISA to determine whether milk LF concentration is influenced by parity of the cow, stage of lactation, and the somatic cell count. The study animals were 198 Chinese Holstein cows randomly chosen from more than 1,600 cows in 4 dairy farms in the Beijing area. The cows had shown no sign of mastitis for 2 mo. Daily milk production was recorded, and milk samples were taken from individual cow samples. The LF concentration varied between 31.78 and 485.63 microg/mL in milk from normal animals. Lactoferrin was significantly associated with stage of lactation (r = 0.557) and daily milk production (r = -0.472). Nevertheless, there was no significant relationship with parity. Moreover, milk LF concentration tended to be correlated with the somatic cell count score (r = 0.375). This finding suggests that milk LF may be helpful as an indicator for intramammary infection in dairy cows.

Observation of locomotor functional recovery in adult complete spinal rats with BWSTT using semiquantitative and qualitative methods

STUDY DESIGN

Experimental rat model of spinal cord transection .

SETTING

China rehabilitation research center.

OBJECTIVE

To investigate locomotor functional recovery in spinal rats with BWSTT using semiquantitative and qualitative methods.

METHODS

Five-day postoperative (dpo), adult female complete spinal rats (at T(8) level) received 40 days of body weight-supported treadmill training (BWSTT). Signs of functional recovery were examined with average combined scores (ACOS) and Basso Beattie and Bresnahan (BBB) scales at different time points.

RESULTS

At 1-dpo, none of the spinal rats exhibited hindlimb movements. The spinal rats displayed functional progress with time, but the rare could recover to full weight-bearing hindlimb at 45-dpo. BBB and ACOS scores in the BWSTT group obtained better scores than those in the spinal cord injury (SCI) group at 30- and 45-dpo. Furthermore, all BBB and ACOS scores of spinal rats reached statistical significance between 7- and 30-dpo, and between 15- and 30-dpo. However, only ACOS but not BBB scores in the SCI and BWSTT groups showed statistics differences between 15- and 45-dpo, and between 30- and 45-dpo. The Spearman correlation coefficients of BBB and ACOS scores were 0.913 and 0.972 for the SCI and BWSTT groups, respectively.

CONCLUSIONS

The results confirmed the existence of partial spontaneous hindlimb functional recovery in adult chronically spinal cord-transected rats, and that BWSTT can improve motor performance. In addition, our study suggests that qualitative and semiquantiative methods are strongly correlated with locomotor recovery in spinal rats, and the latter may be more sensitive in reflecting minor variance at different time points.

Spin-dependent variable range hopping and magnetoresistance in Ti(1-x)Co(x)O(2) and Zn(1-x)Co(x)O magnetic semiconductor films

Magnetic transport properties in Ti(1-x)Co(x)O(2) and Zn(1-x)Co(x)O magnetic semiconductors have been studied experimentally and theoretically. A linear relation of lnρ versus T(-1/2) (ρ is sheet resistance and T is temperature), which shows different slopes and intersections at different magnetic fields, was observed experimentally in the low temperature range. The spin-dependent variable range hopping model has been proposed by taking into account the electron-electron Coulomb interaction and the spin-spin exchange interaction in the same frame, which can well describe the observed magnetic transport properties in Ti(1-x)Co(x)O(2) and Zn(1-x)Co(x)O magnetic semiconductors.

Antisurvivin oligonucleotides inhibit growth and induce apoptosis in human medullary thyroid carcinoma cells

Survivin is a novel member of the inhibitor of apoptosis protein (IAP) family, which is known to be over-expressed in various carcinomas and associated with their biologically aggressive characteristics. The aim of this study was to investigate survivin expression in human medullary thyroid carcinoma (MTC) and a MTC cell line TT, correlate survivin expression with clinicopathologic features of MTC, and test effects of antisurvivin oligonucleotides (ASODNs) on growth and apoptosis of TT cells. Survivin expression was immunohistochemically determined in formalin-fixed and paraffin-embedded specimens obtained from 10 cases of normal thyroid (NT) and 10 cases of MTC, and in TT cells. In TT cells, we confirmed survivin expression and its down-regulation by ASODNs using RT-PCR and Western blot analyses, and investigated effects of ASODNs on viability and growth by MTT assay and apoptosis by apoptotic analyses including DNA laddering assay, acridine orange/ethidium bromide staining and flow cytometric cell cycle analysis. Immunohistochemical analysis showed high survivin expression in MTC and TT cells, whereas no immunoreactivity was detectable in NT. Statistical analyses revealed no significant correlation of survivin expression with the clinicopathologic features of MTC. In TT cells, survivin expression at both mRNA and protein levels was confirmed and could be down-regulated by ASODNs concomitant with decrease in viability and growth, and increase in apoptosis. Our results suggest that survivin plays an important role in MTC independent of the conventional clinicopathologic factors, and ASODNs is a promising survivin-targeted gene therapy for MTC.

Spectral tuning of localised surface plasmon-polariton resonance in metallic nano-crescents

The utilisation of plasmonic effects in metallic nanostructures is gaining importance for applications in molecular sensing. Of special interest is the local field enhancement effect, which enables surface-enhanced Raman scattering and significantly boosts the sensitivity of the Raman technique. For in vivo biological research, the ability to excite the resonance of localised surface plasmon-polaritons within the biological window is often desired. A new nanostructure called the nano-crescent is introduced and exhibits strong plasmonic activities within the biological window using a novel intra-particle plasmonic coupling scheme.

Grain yield responses to moisture regimes in a rice population: association among traits and genetic markers

Drought is a major constraint to rice (Oryza sativa L.) production in rainfed and poorly irrigated environments. Identifying genomic regions influencing the response of yield and its components to water deficits will aid our understanding of the genetic mechanism of drought tolerance (DT) of rice and the development of DT varieties. Grain yield (GY) and its components of a recombinant inbred population developed from a lowland rice and an upland rice were investigated under different water levels in 2003 and 2004 in a rainout DT screening facility. Correlation and path analysis indicated that spikelet fertility (SF) was particularly important for grain yield with direct effect (P=0.60) under drought stress, while spikelet number per panicle (SN) contributed the most to grain yield (P=0.41) under well-watered condition. A total of 32 quantitative trait loci (QTLs) for grain yield and its components were identified. The phenotypic variation explained by individual QTLs varied from 1.29% to 14.76%. Several main effect QTLs affecting SF, 1,000-grain weight (TGW), panicle number (PN), and SN were mapped to the same regions on chromosome 4 and 8. These QTLs were detected consistently across 2 years and under both water levels in this study. Several digenic interactions among yield components were also detected. The identification of genomic regions associated with GY and its components under stress will be useful to improve drought tolerance of rice by marker-aided approaches.

Mycophenolate mofetil therapy for children with lupus nephritis refractory to both intravenous cyclosphosphamide and cyclosporine

We describe mycophenolate mofetil (MMF), a new immunosuppressive agent, to be a therapy of two children with lupus nephritis which were refractory to both cyclophosphamide (CyP) and cyclosporine (CsA). After 11- to 12-month course of MMF treatment, all clinical symptoms of lupus disappeared and serum antibodies became negative. MMF might be a promising curative for cyclophosphamide-resistant lupus nephritis in children. Cyclophosphamide intravenous bolus therapy is generally considered to be the treatment for patients with lupus nephritis. However, there is little guidance about what to do if such therapy fails. Recently, a new immunosuppressive agent, mycophenolate mofetil (MMF), has been used to treat cyclophosphamide-resistant lupus nephritis [Dooley et al. 1999, Gaubitz et al. 1999, Glicklich and Acharga 1998] in adults and has been recognized as a promising curative for lupus nephritis. Up to now, MMF has been adopted widely with solid organ transplantation to prevent or reverse acute rejection [Mathew 1998, Morris-Stiff and Jurewicz 1998] and has been used successfully to treat for rheumatoid arthritis refractory to a variety of other drugs. But there is no report about MMF treatment in children with cyclophosphamide-resistant lupus nephritis. We describe our experience with MMF treatment in two Chinese children with lupus nephritis that were refractory not only to cyclophosphamide but also to cyclosporine.

Opposite effects of nitric oxide and nitroxyl on postischemic myocardial injury

Recent experimental evidence suggests that reactive nitrogen oxide species can contribute significantly to postischemic myocardial injury. The aim of the present study was to evaluate the role of two reactive nitrogen oxide species, nitroxyl (NO(-)) and nitric oxide (NO(.)), in myocardial ischemia and reperfusion injury. Rabbits were subjected to 45 min of regional myocardial ischemia followed by 180 min of reperfusion. Vehicle (0.9% NaCl), 1 micromol/kg S-nitrosoglutathione (GSNO) (an NO(.) donor), or 3 micromol/kg Angeli's salt (AS) (a source of NO(-)) were given i.v. 5 min before reperfusion. Treatment with GSNO markedly attenuated reperfusion injury, as evidenced by improved cardiac function, decreased plasma creatine kinase activity, reduced necrotic size, and decreased myocardial myeloperoxidase activity. In contrast, the administration of AS at a hemodynamically equieffective dose not only failed to attenuate but, rather, aggravated reperfusion injury, indicated by an increased left ventricular end diastolic pressure, myocardial creatine kinase release and necrotic size. Decomposed AS was without effect. Co-administration of AS with ferricyanide, a one-electron oxidant that converts NO(-) to NO(.), completely blocked the injurious effects of AS and exerted significant cardioprotective effects similar to those of GSNO. These results demonstrate that, although NO(.) is protective, NO(-) increases the tissue damage that occurs during ischemia/reperfusion and suggest that formation of nitroxyl may contribute to postischemic myocardial injury.

Endothelin-1 stimulates hydrolysis of phosphatidylcholine by phospholipases C and D in intact rat mesenteric arteries

A characteristic of endothelin-1 (ET-1)-induced contraction is the prolonged duration of the response. Phosphatidylcholine (PC) hydrolysis has been implicated in sustained agonist-induced effects through the formation of the second messengers phosphatidic acid (PA) and diacylglycerol (DAG). Therefore, we have investigated the activation of PC-phospholipase D (PLD) and PC-phospholipase C (PLC) in intact rat mesenteric small arteries stimulated with ET-1 and determined whether PC-derived DAG is necessary for ET-1-induced contraction. PLD activity, measured as phosphatidylethanol (PEt) production in vessels labelled with [3H] or [14C]myristate, was increased in a concentration- and time-dependent manner following ET-1 stimulation, as were [3H]PA levels, peaking at 10 min (ET-1 100 nM) and remaining above control levels for up to 20 min. Inclusion of 0.5% ethanol during ET-1 stimulation reduced [3H]PA levels, but did not alter the time course of formation. In addition, [14C]choline release was increased, confirming PLD-mediated PC hydrolysis. In contrast, DAG levels, measured by [3H]myristate labelling and mass assay, increased transiently at 5 min of ET-1 stimulation only. Analysis of the subclasses of DAG demonstrated an increase in all types of DAG without any enrichment with arachidonate-containing species, indicating PC, not inositol lipid hydrolysis was the source of DAG. The PC-PLC inhibitor D609, 2.5 microg/ml, completely abolished the ET-1-induced increase in [14C]DAG without affecting the increase in [14C]PA, PLD activity or the contractile response. In [14C]choline-labelled vessels, [14C]phosphocholine levels were increased by ET-1 with a similar time course to DAG production. Removal of extracellular Ca2+ and addition of 0.1 or 2 mM EGTA completely inhibited ET-1-stimulated PLD activity. The tyrosine kinase inhibitor tyrphostin A23 (100 microM) abolished ET-1-induced [3H]PA, [3H]PEt and [14C]DAG increases, whilst the negative analogue A1 was without effect. These data suggest that ET-1 couples via a calcium-dependent tyrosine kinase mechanism to PLD and PC-PLC in vascular smooth muscle. PC-derived DAG did not appear to be necessary for the contractile response, whereas sustained formation of PA, generated by PLD activity, implies that this lipid second messenger could be involved in the prolonged contractile response to this peptide.

SP/W-5186, A cysteine-containing nitric oxide donor, attenuates postischemic myocardial injury

The effects of SP/W-5186, a cysteine-containing nitric oxide (.NO) donor, on myocardial reperfusion injury were studied in a rabbit ischemia (45 min) and reperfusion (180 min) model. Five min before reperfusion, either low-dose (0.3 micromol/kg) or high-dose (1 micromol/kg) SP/W-5186 was given intravenously as a bolus. Administration of 0.3 micromol/kg SP/W-5186 did not change mean arterial blood pressure, heart rate or pressure-rate index. However, administration of low-dose SP/W-5186 exerted marked cardioprotective effects as evidenced by improved cardiac functional recovery (P <.05 vs. vehicle), decreased plasma creatine kinase concentration (P <. 01) and reduced infarct size (P <.01). Moreover, administration of SP/W-5186 significantly decreased platelet aggregation (P <.01 vs. vehicle), attenuated polymorphonuclear leukocyte (PMN) accumulation in myocardial tissue, inhibited PMN adhesion to endothelial cells and preserved endothelial function. Administration of high-dose SP/W-5186 resulted in a transient but significant decrease in mean arterial blood pressure and exerted more cardiac protection compared with low-dose treatment. However, the effects on platelet aggregation, PMN accumulation and PMN adhesion did not differ significantly between the two SP/W-5186 groups. Furthermore, administration of SP/W-6373, an analogue of SP/W-5186 that lacks the NO moiety, failed to exert any protective effects. These results demonstrate that NO released from SP/W-5186 significantly protected myocardial tissue from reperfusion injury. The primary mechanisms of the observed cardioprotection by SP/W-5186 involve inhibition of platelet aggregation, attenuation of PMN-endothelium interaction and preservation of endothelial function.

Evidence for NOS-containing renal neuronal somata transiently expressing a catecholaminergic phenotype during development in the rat

Transiently catecholaminergic cells (TC-cells) expressing tyrosine hydroxylase (TH) have been shown in a variety of tissues during embryonic life. To investigate the possible relationship of nitric oxide synthase (NOS)-containing renal neuronal somata (RNS) and the TC-cells, we examined serial 100 microm slices of whole kidneys for TH-immunofluorescence and NADPH-d histochemistry during prenatal and postnatal development. The number of TH-cells increased during the prenatal period, peaked at birth and were very rare by PD21. A subpopulation of TH-immunoreactive RNS displayed NADPH-d activity. By PD21 the TH-positive RNS had practically disappeared while the number of NADPH-d positive RNS was markedly increased. These results suggest that kidneys possess transient catecholaminergic cells which display NOS-activity and that NOS expression may be the end-point in the differentiation of the RNS.

Comparison of metoprolol and carvedilol pharmacology and cardioprotection in rabbit ischemia and reperfusion model

Carvedilol, a selective alpha1 and non-selective beta-adrenoceptor antagonist and antioxidant, has been shown to provide significant cardiac protection in animal models of myocardial ischemia. To further explore the mechanisms contributing to carvedilol cardioprotection efficacy, the effects of carvedilol on hemodynamic variables, infarct size and myeloperoxidase activity (an index of neutrophil accumulation) were compared with a beta1-selective adrenoceptor antagonist, metoprolol. Carvedilol (1 mg/kg) or metoprolol (1 mg/kg or 1 mg/kg + 0.5 mg/kg 90 min later) was given intravenously 5 min before reperfusion. In vehicle-treated rabbits, ischemia (60 min) and reperfusion (180 min) resulted in significant increments in left ventricular end diastolic pressure, large infarcts (59+/-2.6% of area-at-risk) and marked increase in myeloperoxidase activity (0.59+/-0.09 U/100 mg tissue). Carvedilol treatment resulted in sustained reduction of pressure-rate-index and significantly smaller infarcts (22.0+/-2.5%, P < 0.01 vs. vehicle) as well as decreased myeloperoxidase activity (0.186+/-0.056 U/100 mg tissue, P < 0.01 vs. vehicle). The highest dose of metoprolol, 1 mg/kg + 0.5 mg/kg, that resulted in pressure-rate-index comparable to that of 1.0 mg/kg carvedilol, failed to reduce myeloperoxidase activity in the ischemic myocardial tissue, and the infarct size (35+/-3.1%) was significantly larger than in carvedilol-treated animals. Taken together, this study suggests that the superior cardioprotection of carvedilol over metoprolol is not a consequence of hemodynamic variances but possibly the result of the additional pharmacological properties of carvedilol such as the antioxidant and anti-neutrophil effects.

Possible involvement of stress-activated protein kinase signaling pathway and Fas receptor expression in prevention of ischemia/reperfusion-induced cardiomyocyte apoptosis by carvedilol

Carvedilol, a new vasodilating beta-adrenoceptor antagonist and a potent antioxidant, produces a high degree of cardioprotection in a variety of experimental models of ischemic cardiac injury. Recent clinical studies in patients with heart failure have demonstrated that carvedilol reduces morbidity and mortality and inhibits cardiac remodeling. The present study was designed to explore whether the protective effects of carvedilol on the ischemic myocardium include inhibition of apoptosis of cardiomyocytes and, if so, to determine its mechanism of action. Anesthetized rabbits were subjected to 30 minutes of coronary artery occlusion followed by 4 hours of reperfusion. Detection of apoptosis of cardiomyocytes was based on the presence of nucleosomal DNA fragments on agarose gels (DNA ladder) and in situ nick end labeling. Carvedilol (1 mg/kg IV), administered 5 minutes before reperfusion, reduced the number of apoptotic myocytes in the ischemic area from 14.7 +/- 0.4% to 3.4 +/- 1.8% (77% reduction, P<.001). Propranolol, administered at equipotent beta-blocking dosage, reduced the number of apoptotic myocytes to 8.9 +/- 2.1% (39% reduction, P<.05). DNA ladders were observed in the hearts of all six vehicle-treated rabbits but only one of six carvedilol-treated rabbits (P<.01). Immunocytochemical analysis of rabbit hearts demonstrated an upregulation of Fas protein in ischemic cardiomyocytes, and treatment with carvedilol reduced both the intensity of staining as well as the area stained. Myocardial ischemia/reperfusion led to a rapid activation of stress-activated protein kinase (SAPK) in the ischemic area but not in nonischemic regions. SAPK activity was increased from 2.1 +/- 0.3 mU/mg (basal) to 8.9 +/- 0.8 mU/mg after 30 minutes of ischemia followed by 20 minutes of reperfusion. Carvedilol inhibited the activation of SAPK by 53.4 +/- 6.5% (P<.05). Under the same conditions, propranolol (1 mg/kg) had no effect on SAPK activation. Taken together, these results suggest that carvedilol prevents myocardial ischemia/reperfusion-induced apoptosis in cardiomyocytes possibly by downregulation of the SAPK signaling pathway, by inhibition of Fas receptor expression, and by beta-adrenergic blockade. The former two actions represent novel and important mechanisms that may contribute to the cardioprotective effects of carvedilol.

Peroxynitrite aggravates myocardial reperfusion injury in the isolated perfused rat heart

OBJECTIVE

This study examined the effects of peroxynitrite (ONOO-) on cardiac function and cellular injury following ischemia (30 min) and reperfusion (60 min) in isolated perfused rat hearts.

METHODS

3-Morpholinosydnonimine (SIN-1, 0.1 mM), an ONOO- donor, was administered alone or combined with superoxide dismutase (SOD, 300 U/ml) or glutathione (GSH, 1 mM) at the time of reperfusion.

RESULTS

Administration of SIN-1 alone significantly aggravated post-ischemic myocardial injury characterized by depressed cardiac function recovery (p < 0.05 vs. vehicle), increased lactic dehydrogenase (LDH) and creatine kinase (CK) release (p < 0.01 vs. vehicle), and enlarged necrotic size (p < 0.01 vs. vehicle). The co-administration of either SOD to decrease the formation of ONOO-, or GSH to increase the detoxification of ONOO-, completely blocked the detrimental effects of SIN-1 and exerted significant cardioprotective effects against reperfusion injury.

CONCLUSION

These results suggest that ONOO- may play a significant role in postischemic myocardial injury.

Hypercholesterolemia impairs a detoxification mechanism against peroxynitrite and renders the vascular tissue more susceptible to oxidative injury

Previous studies have shown that glutathione (GSH) plays a central role in the protection against peroxynitrite (ONOO-) toxicity. The present study evaluated the changes of the GSH cytoprotective system against ONOO- in hypercholesterolemia and determined the effects of carvedilol, a beta-blocker with free radical-scavenging activity, on these hypercholesterol-induced changes. New Zealand White rabbits were fed either a normal diet, a high-cholesterol diet, or a high-cholesterol diet supplemented with either carvedilol or propranolol. Eight weeks later, the rabbits were killed, and the thoracic aortas were isolated. Total GSH content of aortic tissue, vasorelaxation response of aortic rings to exogenous ONOO-, No regeneration from ONOO- by aortic homogenate, and ONOO(-)-induced aortic tissue injury were examined. Hypercholesterolemia decreased tissue GSH content (0.52 +/- 0.08 versus 0.86 +/- 0.04 mumol/g in control, P < .01), attenuated the vasorelaxation response to ONOO- (40 +/- 4.1% versus 76 +/- 3.2%, P < .01), reduced NO regeneration from ONOO- (387 +/- 40 versus 662 +/- 51 pmol, P < .01), and potentiated ONOO(-)-induced vascular tissue injury (37 +/- 4.4% versus 14 +/- 2.6% of increase in lactate dehydrogenase release after 3-morpholinosydnonimine exposure, P < .01). Treatment of the hypercholesterolemic rabbits with carvedilol, but not propranolol, significantly preserved tissue GSH content (0.79 +/- 0.05 mumol/g, P < .01 versus nontreated hypercholesterolemic rabbits), restored the vasorelaxation to ONOO- (61 +/- 2%, P < .01), increased NO regeneration from ONOO- (583 +/- 39 pmol, P < .01), and attenuated ONOO(-)-induced tissue injury (19 +/- 1.8%, P < .01). These results suggest that hypercholesterolemia impairs the GSH-mediated detoxification mechanism against ONOO- and renders the vascular tissue more susceptible to oxidative injury. Carvedilol, a novel vasodilating beta-blocker with antioxidant activity, significantly preserved this self-defense system and protected tissue from oxidant injury.

Peroxynitrite, the product of nitric oxide and superoxide, causes myocardial injury in the isolated perfused rat heart

BACKGROUND

Recent studies have determined that the product of NO and superoxide is peroxynitrite (ONOO-), an anion with deleterious tissue-oxidant effects.

OBJECTIVE

To examine the effects of ONOO- on the isolated perfused rat heart. Sprague-Dawley rat hearts were perfused with a cell-free, Krebs-Henseleit solution on a Langendorf perfusion apparatus. The hearts were subjected to 30 min infusions of vehicle (control); 10 mumol/l S-nitroso-N-acetylpenicillamine (SNAP), an NO donor; 10 mumol/l pyrogallol, a superoxide generator); 10 mumol/l SNAP plus 10 mumol/l pyrogallol, a mixture that generates peroxynitrite; or 10 mumol/l SNAP plus 10 mumol/l pyrogallol plus 300 U/ml superoxide dismutase.

RESULTS

SNAP or pyrogallol alone had no effect on cardiac function at the concentration used; however, infusion of the combination of SNAP and pyrogallol resulted in significant decreases in left ventricular developed pressure (to 83 +/- 4%, P < 0.01, versus vehicle) and dp/dtmax (to 76 +/- 6.2%, P < 0.01, versus vehicle), and also resulted in a significant increase in production of lactic dehydrogenase (to 118 +/- 4%, P < 0.01, versus vehicle). The administration of superoxide dismutase with SNAP and pyrogallol reversed these deleterious effects.

CONCLUSION

These results suggest that the formation of peroxynitrite significantly enhances the toxicities of .NO and O2.- and causes marked cardiac injury.

Distribution of nitric oxide synthase-containing ganglionic neuronal somata and postganglionic fibers in the rat kidney

Nitric oxide synthase (NOS)-immunoreactive neurons were identified in the rat kidney by using an antibody against type Ia NOS and the avidin-biotin complex immunoperoxidase method in whole kidneys examined in 100 microns serial sections. The histochemical method for demonstration of the nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) was also used to characterize NOS-containing neurons. All somata showing NOS immunoreactivity also displayed NADPH-d activity. The greatest number of neuronal somata were observed in groups at the wall of the renal pelvis and in the angular space formed by the pole of the renal parenchyma and renal pelvic wall. They were also seen at the renal hilus close to the renal artery and along the interlobar vasculature. The size of the neuronal somata in the 35-day-old rat ranged from 13.6 to 34.8 microns, with a mean size of 21.52 +/- 4.81 microns. Seventy percent, however, ranged in size from 17.8 to 26.8 microns. The shape of the neuronal somata also varied, with the majority having an ovoid or round shape. The distribution of the postganglionic fibers was investigated by means of the camera lucida. Postganglionic fibers projected into the wall of the renal pelvis and/or to the interlobar arteries extending to the arcuate arteries and to the beginning of the afferent arterioles. The NOS-immunoreactive neurons may have a vasodilator and relaxing function on the renal pelvic wall and vasculature. In addition, the presence of NOS-containing nerve fibers in nerve bundles, which are known to have predominantly vasomotor and sensory fibers, suggest that they may have a possible modulatory role on renal neural function.

Development of NOS-containing neuronal somata in the rat kidney

An investigation of the changes in size, number and distribution of NOS-containing neuronal somata in the rat kidney was undertaken. The immunoperoxidase method for the staining of NOS and the histochemical method for the demonstration of NADPH-d were applied to serial thick sections (100 microns) of whole kidneys. Animals at embryonic day 14 (ED14), ED16, ED18, ED20, at birth (PD0), and at postnatal days 4 (PD4), PD12, PD21 and PD35 were studied. NOS-containing neuronal somata were observed by the 20th day of gestation in some kidneys and were consistently seen at birth. They were usually seen in groups of separated neuronal somata or in tight clusters. The neuronal somata were often attached or embedded in nerve bundles. As the kidney developed, the number of neuronal somata separated from each other increased, while the number of clusters remained relatively constant. The size of the neuronal somata increased with development. There were highly significant statistical differences in the size of the neuronal somata between all groups, except between PD12 and PD21. The distribution of neuronal somata at birth was similar to that of the adult. They could be found, (a) at the free renal pelvic wall; (b) in the connective tissue at the angular space between the renal pelvis and the renal parenchyma (SPP); and (c) along the interlobar vessels. At birth and in the early stages of development, the greatest number of neuronal somata were located at the renal pelvis. In the later stages of development, more neuronal somata appear in the connective tissue between the renal pelvis and the renal parenchyma. The location of NOS-containing neuronal somata suggests that they might have a modulatory role on the sympathetic and sensory renal nerves all through development.

Colocalization of NADPH-diaphorase and dopamine beta-hydroxylase in the neuronal somata of the rat kidney

Neuronal somata in the rat kidney are very often part of ganglionated plexus and contain nitric oxide synthase (NOS). Examining serial 100 microns slices of whole kidneys, we identified three subpopulations of neuronal somata by: (a) staining for NADPH-diaphorase (NADPH-d) histochemistry followed by the demonstration of dopamine beta-hydroxylase (DBH) by immunoperoxidase, and (b) staining for DBH by immunofluorescence followed by the demonstration of NADPH-d histochemical activity. The largest subpopulation of neuronal somata displayed both DBH immunoreactivity and NADPH-d histochemical activity. The second largest group of somata showed NADPH-d activity only. A small group of neuronal somata showed only DBH immunoreactivity. The presence of catecholaminergic characteristics in NOS-containing neuronal somata is unusual and raises the question as to their origin. Their heterogeneity suggests different functions for the different subpopulations.