High-power, diode-end-pumped, multigigahertz self-mode-locked Nd:YVO4 laser at 1342 nm

We report on a high-power, diode-pumped, self-mode-locked laser at 1342 nm with the Kerr effect arising from large third-order nonlinearity of Nd:YVO(4) crystal. At the pump power of 10.2 W, the average output power of 1.2 W was generated with a repetition rate in the range of 2-6 GHz. The mode-locked pulse width can be smoothly varied from 11.5 to 37 ps by controlling the amount of spatial hole burning.

The suppression of MAD1 by AKT-mediated phosphorylation activates MAD1 target genes transcription

MAX dimerization protein 1 (MAD1) is a transcription suppressor that antagonizes MYC-mediated transcription activation, and the inhibition mechanism occurs mainly through the competition of target genes' promoter MYC binding sites by MAD1. The promoter binding proteins switch between MYC and MAD1 affects cell proliferation and differentiation. However, little is known about MAD1's regulation process in cancer cells. Here, we present evidence that AKT inhibits MAD1-mediated transcription repression by physical interaction with and phosphorylation of MAD1. Phosphorylation reduces the binding affinity between MAD1 and its target genes' promoter and thereby abolishes its transcription suppression function. Mutation of the phosphorylation site from serine to alanine rescues the DNA-binding ability in the presence of activated AKT. In addition, AKT inhibits MAD1-mediated target genes (hTERT and ODC) transcription repression and promotes cell cycle and cell growth. However, mutated S145A MAD1 abrogates the inhibition by AKT. Thus, our results suggest that phosphorylation of MAD1 by AKT inhibits MAD1-mediated transcription suppression and subsequently activates the transcription of MAD1 target genes.

Comparative studies for Cr4+:YAG crystal and AlGaInAs semiconductor used as a saturable absorber in Q-switched Yb-doped fiber lasers

We demonstrate comparative studies for Cr(4+):YAG crystal and AlGaInAs quantum-well (QW) used as a saturable absorbers in passively Q-switched Yb-doped fiber lasers. Both saturable absorbers were designed to be possessed of nearly the same initial transmission. Under a pump power of 24 W, the average output powers were up to 14.4 W and 13.8 W obtained with the AlGaInAs QWs and with the Cr(4+):YAG crystal, respectively. The maximum pulse energies obtained with the Cr(4+):YAG crystal and with the AlGaInAs QWs were found to be 0.35 mJ and 0.45 mJ, respectively.

Induction of Akt activity by chemotherapy confers acquired resistance

Resistance to chemotherapy is a major cause of treatment failure in human cancer. Accumulating evidence has indicated that the acquisition of resistance to chemotherapeutic drugs involves the activation of the PI3K/Akt pathway. Modulating Akt activity in response to chemotherapy has been observed often in chemoresistant cancers. The potential molecular mechanisms by which chemotherapeutic agents activate the PI3K/Akt pathway are emerging. Activation of this pathway evades the cytotoxic effects of chemotherapeutic agents via regulation of essential cellular functions such as protein synthesis, antiapoptosis, survival and proliferation in cancer. How chemotherapeutic agents induce Akt activation and how activated Akt confers chemoresistance through regulation of signaling networks are discussed in this review. Combining PI3K/Akt inhibitors with standard chemotherapy has been successful in increasing the efficacy of chemotherapeutic agents both in vivo and in vitro. Several small molecules have been developed to specifically target PI3K/Akt and other components of this pathway, which in combination with chemotherapy may be a valid approach to overcome therapeutic resistance. We propose several feedback and feedforward regulatory mechanisms of signaling networks for maintenance of the Akt activity for cell survival. These regulatory mechanisms may limit the efficacy of PI3K/Akt-targeted therapy; therefore, disruption of these mechanisms may be an effective strategy for development of novel anti-cancer therapies.

High-pulse-energy, passively Q-switched Yb-doped fiber laser with AlGaInAs quantum wells as a saturable absorber

We demonstrate an efficient, high-pulse-energy, passively Q-switched Yb-doped fiber laser with AlGaInAs quantum wells (QWs) as a saturable absorber. The AlGaInAs QW material is designed to provide a large modulation change and a quite-low nonsaturable loss. At an incident pump power of 7.6 W, an average output power of 3.8 W, pulse energy of 300 microJ, pulse repetition rate of 12.5 kHz, and pulse duration of 30 ns was obtained.

Inhibiting glycogen synthase kinase-3 reduces endotoxaemic acute renal failure by down-regulating inflammation and renal cell apoptosis

BACKGROUND AND PURPOSE

Excessive inflammation and apoptosis are pathological features of endotoxaemic acute renal failure. Activation of glycogen synthase kinase-3 (GSK-3) is involved in inflammation and apoptosis. We investigated the effects of inhibiting GSK-3 on lipopolysaccharide (LPS)-induced acute renal failure, nuclear factor-kappaB (NF-kappaB), inflammation and apoptosis.

EXPERIMENTAL APPROACH

The effects of inhibiting GSK-3 with inhibitors, including lithium chloride (LiCl) and 6-bromo-indirubin-3'-oxime (BIO), on LPS-treated (15 mg x kg(-1)) C3H/HeN mice (LiCl, 40 mg x kg(-1) and BIO, 2 mg x kg(-1)) and LPS-treated (1 microg x mL(-1)) renal epithelial cells (LiCl, 20 mM and BIO, 5 microM) were studied. Mouse survival was monitored and renal function was analysed by histological and serological examination. Cytokine and chemokine production, and cell apoptosis were measured by enzyme-linked immunosorbent assay and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling staining, respectively. Activation of NF-kappaB and GSK-3 was determined by immunostaining and Western blotting, respectively.

KEY RESULTS

Mice treated with GSK-3 inhibitors showed decreased mortality, renal tubular dilatation, vacuolization and sloughing, blood urea nitrogen, creatinine and renal cell apoptosis in response to endotoxaemia. Inhibiting GSK-3 reduced LPS-induced tumour necrosis factor-alpha (TNF-alpha) and CCL5/RANTES (released upon activation of normal T-cells) in vivo in mice and in vitro in murine kidney cortical collecting duct epithelial M1 cells. Inhibiting GSK-3 did not block TNF-alpha-induced cytotoxicity in rat kidney proximal tubular epithelial NRK52E or in M1 cells.

CONCLUSIONS AND IMPLICATIONS

These results suggest that GSK-3 inhibition protects against endotoxaemic acute renal failure mainly by down-regulating pro-inflammatory TNF-alpha and RANTES.

Loss of IKKbeta activity increases p53 stability and p21 expression leading to cell cycle arrest and apoptosis

Elevated levels of NF-kappaB are frequently detected in many inflammatory diseases and cancers. Blocking the IKK-NF-kappaB pathway has been seen as a promising approach for new therapies. By employing the dominant-negative mutant of IKKbeta, our data revealed that loss of IKKbeta activity reduces not only the proliferation and invasion of lung adenocarcinoma A549 cells in vitro but also the tumour formation, metastasis and angiogenesis in mouse xenograft model. Treatment of IKKbeta inhibitors (CYL-19s and CYL-26z) leads to the arrest of cell cycle progression at G1 and G2/M, followed by apoptosis. IKKbeta inhibitors can increase the protein stability, nuclear accumulation and promoter-binding activity of p53, leading to the p21 gene transcription. Furthermore, knockdown of IKKbeta by siRNA increased the stability and expression of p53 and p21 promoter activity. In addition, IKKbeta inhibitor-induced p53 and p21 expressions were augmented in the presence of IKKbeta siRNA. Correlation between p53 acetylation and its protein stabilization was also seen after treatment with IKKbeta inhibitors. These results suggest that loss of IKKbeta activation is important for the enhancement of p53 stability, leading to p21 expression and cell cycle arrest and apoptosis of tumour cells.

Survival of cancer cells is maintained by EGFR independent of its kinase activity

Expression of the epidermal growth factor receptor (EGFR), a receptor tyrosine kinase associated with cell proliferation and survival, is overactive in many tumors of epithelial origin. Blockade of the kinase activity of EGFR has been used for cancer therapy; however, by itself, it does not seem to reach maximum therapeutic efficacy. We report here that in human cancer cells, the function of kinase-independent EGFR is to prevent autophagic cell death by maintaining intracellular glucose level through interaction and stabilization of the sodium/glucose cotransporter 1 (SGLT1).

Primary mediastinal large B-cell lymphoma mimicking liposarcoma

A 78-year-old man consulted for acute exacerbation of chronic obstructive pulmonary disease (COPD) and an incidental finding of an anterior mediastinal tumor on chest radiograph was noted on admission. Chest computed tomography (CT) revealed a fat-containing mediastinal mass with solid component. Mediastinal liposarcoma was the initial diagnosis based on image characteristics but histopathologic examination of the excised tumor revealed lymphoma infiltration of the mediastinal adipose tissue. To our knowledge, this is the first case report of lymphomatous growth in mediastinal lipomatosis.

IKK beta suppression of TSC1 links inflammation and tumor angiogenesis via the mTOR pathway

TNFalpha has recently emerged as a regulator linking inflammation to cancer pathogenesis, but the detailed cellular and molecular mechanisms underlying this link remain to be elucidated. The tuberous sclerosis 1 (TSC1)/TSC2 tumor suppressor complex serves as a repressor of the mTOR pathway, and disruption of TSC1/TSC2 complex function may contribute to tumorigenesis. Here we show that IKKbeta, a major downstream kinase in the TNFalpha signaling pathway, physically interacts with and phosphorylates TSC1 at Ser487 and Ser511, resulting in suppression of TSC1. The IKKbeta-mediated TSC1 suppression activates the mTOR pathway, enhances angiogenesis, and results in tumor development. We further find that expression of activated IKKbeta is associated with TSC1 Ser511 phosphorylation and VEGF production in multiple tumor types and correlates with poor clinical outcome of breast cancer patients. Our findings identify a pathway that is critical for inflammation-mediated tumor angiogenesis and may provide a target for clinical intervention in human cancer.

Phosphorylation of CBP by IKKalpha promotes cell growth by switching the binding preference of CBP from p53 to NF-kappaB

CBP plays a central role in coordinating and integrating multiple signaling pathways. Competition between NF-kappaB and p53 for CBP is a crucial determinant of whether a cell proliferates or undergoes apoptosis. However, how the CBP-dependent crosstalk between these two transcription factors is regulated remains unclear. Here, we show that IKKalpha phosphorylates CBP at serine 1382 and serine 1386 and consequently increases CBP's HAT and transcriptional activities. Importantly, such phosphorylation enhances NF-kappaB-mediated gene expression and suppresses p53-mediated gene expression by switching the binding preference of CBP from p53 to NF-kappaB, thus promoting cell growth. The CBP phosphorylation also correlates with constitutive IKKalpha activation in human lung tumor tissue compared with matched nontumor lung tissue. Our results suggest that phosphorylation of CBP by IKKalpha regulates the CBP-mediated crosstalk between NF-kappaB and p53 and thus may be a critical factor in the promotion of cell proliferation and tumor growth.

Transcriptional regulation of cyclooxygenase-2 in response to proteasome inhibitors involves reactive oxygen species-mediated signaling pathway and recruitment of CCAAT/enhancer-binding protein delta and CREB-binding protein

Inhibition of ubiquitin-proteasome pathway has been shown to be a promising strategy for the treatment of inflammation and cancer. Here, we show that proteasome inhibitors MG132, PSI-1, and lactacystin induce COX-2 expression via enhancing gene transcription rather than preventing protein degradation in the human alveolar NCI-H292 and A549, and gastric AGS epithelial cells. NF-IL6 and CRE, but not NF-kappaB elements on the COX-2 promoter were involved in the gene transcription event. The binding of CCAAT/enhancer binding protein (C/EBP)beta and C/EBPdelta to the CRE and NF-IL6 elements, as well as the recruitment of CBP and the enhancement of histone H3 and H4 acetylation on the COX-2 promoter was enhanced by MG132. However, it did not affect the total protein levels of C/EBPbeta and C/EBPdelta. MG132-induced DNA-binding activity of C/EBPdelta, but not C/EBPbeta was regulated by p38, PI3K, Src, and protein kinase C. Small interfering RNA of C/EBPdelta suppressed COX-2 expression, further strengthening the role of C/EBPdelta in COX-2 gene transcription. In addition, the generation of intracellular reactive oxygen species (ROS) in response to MG132 contributed to the activation of MAPKs and Akt. These findings reveal that the induction of COX-2 transcription induced by proteasome inhibitors requires ROS-dependent protein kinases activation and the subsequent recruitments of C/EBPdelta and CBP.

Akt phosphorylation of p300 at Ser-1834 is essential for its histone acetyltransferase and transcriptional activity

The PI3K/Akt pathway plays a critical role in the regulation of gene expression induced by numerous stimuli. p300, a transcriptional coactivator, acts in concert with transcription factors to facilitate gene expression. Here, we show that Akt is activated and translocated to the nucleus in response to tumor necrosis factor alpha. Nuclear Akt associates with p300 and phosphorylates its Ser-1834 both in vivo and in vitro. The phosphorylation induces recruitment of p300 to the ICAM-1 promoter, leading to the acetylation of histones in chromatin and association with the basal transcriptional machinery RNA polymerase II. These two events facilitate ICAM-1 gene expression and are abolished by the p300 S1834A mutant, inhibitors of PI3K/Akt, or small interfering RNA of Akt. Histone acetylation is attributed to the Akt-enhanced intrinsic histone acetyltransferase (HAT) activity of p300 and its association with another HAT, p/CAF. Our study provides a new insight into the molecular mechanism by which Akt promotes the transcriptional potential of p300.

Inhibition of ICAM-1 gene expression, monocyte adhesion and cancer cell invasion by targeting IKK complex: molecular and functional study of novel alpha-methylene-gamma-butyrolactone derivatives

The transcription factor nuclear factor-kappaB (NF-kappaB) is a regulator related to cellular inflammation, immune responses and carcinogenesis. Therefore, components of the NF-kappaB-activating singnaling pathways are frequent targets for the anti-inflammatory and anticancer agents. In this study, CYL-19 s and CYL-26z, two synthetic alpha-methylene-gamma-butyrolactone derivatives, were shown to inhibit the tumor necrosis factor-alpha (TNF-alpha)-induced intercellular adhesion molecule-1 (ICAM-1) expression in human A549 alveolar epithelial cells and the adhesion of U937 cells to these cells. RT-PCR analysis also demonstrated their inhibitory effects on TNF-alpha-induced ICAM-1 mRNA expression. TNF-alpha-induced ICAM-1 and NF-kappaB-dependent promoter activities were attenuated by CYL-19 s and CYL-26z. ICAM-1 promoter activities induced by the over-expression of wild-type NF-kappaB-inducing kinase and IkappaB kinase beta (IKKbeta) were also inhibited by both compounds. Furthermore, CYL-19 s and CYL-26z inhibited the TNF-alpha-induced phosphorylation and degradation of IkappaBalpha and NF-kappaB-specific DNA-protein binding activity via targeting IKK complex directly, without any effect on the activations of other kinases such as ERK1/2 and p38. In addition to ICAM-1 expression, CYL-19 s and CYL-26z also suppressed other NF-kappaB-mediated gene expressions such as matrix metalloproteinase-9 (MMP-9) mRNA and cyclooxygnease-2 (COX-2) protein. In Matrigel assays, ICAM-1 and COX-2 expressions induced by TNF-alpha elicited A549 and NCI-H292 cell invasion, respectively, and these effects were inhibited by both compounds. In summary, our data demonstrated that CYL-19 s and CYL-26z down-regulate the TNF-alpha-induced inflammatory genes expression through suppression of IKK activity and NF-kappaB activation. These agents may be effective in the anti-inflammatory and anticancer therapy.

Tyrosine phosphorylation of I-kappa B kinase alpha/beta by protein kinase C-dependent c-Src activation is involved in TNF-alpha-induced cyclooxygenase-2 expression

The signaling pathway involved in TNF-alpha-induced cyclooxygenase-2 (COX-2) expression was further studied in human NCI-H292 epithelial cells. A protein kinase C (PKC) inhibitor (staurosporine), tyrosine kinase inhibitors (genistein and herbimycin A), or a Src kinase inhibitor (PP2) attenuated TNF-alpha- or 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced COX-2 promoter activity. TNF-alpha- or TPA-induced I-kappaB kinase (IKK) activation was also blocked by these inhibitors, which reversed I-kappaBalpha degradation. Activation of c-Src and Lyn kinases, two Src family members, was inhibited by the PKC, tyrosine kinase, or Src kinase inhibitors. The dominant-negative c-Src (KM) mutant inhibited induction of COX-2 promoter activity by TNF-alpha or TPA. Overexpression of the constitutively active PKCalpha (PKCalpha A/E) or wild-type c-Src plasmids induced COX-2 promoter activity, and these effects were inhibited by the dominant-negative c-Src (KM), NF-kappaB-inducing kinase (NIK) (KA), or IKKbeta (KM) mutant. The dominant-negative PKCalpha (K/R) or c-Src (KM) mutant failed to block induction of COX-2 promoter activity caused by wild-type NIK overexpression. In coimmunoprecipitation experiments, IKKalpha/beta was found to be associated with c-Src and to be phosphorylated on its tyrosine residues after TNF-alpha or TPA treatment. Two tyrosine residues, Tyr(188) and Tyr(199), near the activation loop of IKKbeta, were identified to be crucial for NF-kappaB activation. Substitution of these residues with phenylalanines attenuated COX-2 promoter activity and c-Src-dependent phosphorylation of IKKbeta induced by TNF-alpha or TPA. These data suggest that, in addition to activating NIK, TNF-alpha also activates PKC-dependent c-Src. These two pathways cross-link between c-Src and NIK and converge at IKKalpha/beta, and go on to activate NF-kappaB, via serine phosphorylation and degradation of IkappaB-alpha, and, finally, to initiate COX-2 expression.

c-Src-dependent tyrosine phosphorylation of IKKbeta is involved in tumor necrosis factor-alpha-induced intercellular adhesion molecule-1 expression

The signaling pathway involved in tumor necrosis factor-alpha (TNF-alpha)-induced intercellular adhesion molecule-1 (ICAM-1) expression was further studied in human A549 epithelial cells. TNF-alpha- or 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ICAM-1 promoter activity was inhibited by a protein kinase C (PKC) inhibitor (staurosporine), tyrosine kinase inhibitors (genistein and herbimycin A), or an Src-specific tyrosine kinase inhibitor (PP2). TNF-alpha- or TPA-induced IkappaBalpha kinase (IKK) activation was also blocked by these inhibitors, which slightly reversed TNF-alpha-induced but completely reversed TPA-induced IkappaBalpha degradation. c-Src and Lyn, two members of the Src kinase family, were abundantly expressed in A549 cells, and their activation by TNF-alpha or TPA was inhibited by the same inhibitors. Furthermore, the dominant-negative c-Src (KM) mutant inhibited induction of ICAM-1 promoter activity by TNF-alpha or TPA. Overexpression of the constitutively active PKC or wild-type c-Src plasmids induced ICAM-1 promoter activity, this effect being inhibited by the dominant-negative c-Src (KM) or IKKbeta (KM) mutant but not by the nuclear factor-kappaB-inducing kinase (NIK) (KA) mutant. The c-Src (KM) mutant failed to block induction of ICAM-1 promoter activity caused by overexpression of wild-type NIK. In co-immunoprecipitation and immunoblot experiments, IKK was found to be associated with c-Src and to be phosphorylated on tyrosine residues after TNF-alpha or TPA treatment. Two tyrosine residues, Tyr188 and Tyr199, near the activation loop of IKKbeta, were identified as being important for NF-kappaB activation. Substitution of these residues with phenylalanines abolished ICAM-1 promoter activity and c-Src-dependent phosphorylation of IKKbeta induced by TNF-alpha or TPA. These data suggest that, in addition to activating NIK, TNF-alpha also activates PKC-dependent c-Src. These two pathways converge at IKKbeta and go on to activate NF-kappaB, via serine phosphorylation and degradation of IkappaB-alpha, and, finally, to initiate ICAM-1 expression.

Automated nasopharyngeal carcinoma detection with dynamic gadolinium-enhanced MR imaging

OBJECTIVES

The purpose of this research is to develop an automatic medical diagnosis for segmenting nasopharyngeal carcinoma (NPC) with dynamic gadolinium-enhanced MR imaging.

METHODS

This system is a multistage process, involving motion correction, head mask generation, dynamic MR data quantitative evaluation, rough segmentation, and rough segmentation refinement. Two approaches, a relative signal increase method and a slope method, are proposed for the quantitative evaluation of dynamic MR data.

RESULTS

The NPC detection results obtained using the proposed methods had a rating of 85% in match percent compared with these lesions identified by an experienced radiologist. The match percent for the two proposed methods did not have significant differences. However, the computation cost for the slope method was about twelve times faster than the relative signal increase method.

CONCLUSIONS

The proposed methods can identify the NPC regions quickly and effectively. This system can enhance the performance of clinical diagnosis.

Protein kinase C and changes in manganese superoxide dismutase gene expression in cultured glial cells

1. To study the role of protein kinase C (PKC) in the increase in manganese superoxide dismutase (Mn-SOD) gene expression following transient hypoxia in glial cells, we examined the mRNA levels of Mn-SOD using northern blot analysis. 2. The Mn-SOD mRNA levels were markedly increased after exposure to nitrogen gas for 5 min. 3. Pretreatment with chelerythrine or GF109203x, inhibitors of PKC, attenuated the increase in Mn-SOD mRNA following hypoxia in a concentration-dependent manner. 4. Incubation with phorbol 12-myristate 13-acetate, the PKC activator, enhanced the increase in Mn-SOD gene expression in response to transient hypoxia. 5. The results suggest that hypoxia increases Mn-SOD gene expression in cultured glial cells mainly through activation of a PKC pathway.

Inhibition of nitric oxide synthesis accentuates blood pressure elevation in hyperinsulinemic rats

OBJECTIVES

To examine the role of endogenous nitric oxide (NO) in the pathogenesis of hypertension and insulin resistance in chronic hyperinsulinemic rats.

METHODS

Sustained hyperinsulinemia was achieved by insulin infusion (21.5 pmol/kg per min) via subcutaneous osmotic minipump for 6 weeks. NO synthase inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME, 5 mg/kg per day) was given orally after 4 weeks of vehicle or insulin infusion. The systolic blood pressure (SBP) was measured under conscious state by an electrosphygmomanometer before and after drug treatments.

RESULTS

Insulin infusion alone significantly increased SBP from 134 +/- 3 to 156 +/- 2 mmHg by week 4 and further to 158 +/- 3 mmHg by week 6 of insulin infusion. The insulin-infused rats had markedly decreased insulin sensitivity, as reflected by an elevated steady-state plasma glucose level estimated by the insulin suppression test. There were no significant differences in plasma glucose and triglyceride levels between rats with and without insulin infusion. When hypertension had been established in rats receiving insulin infusion for 4 weeks, superimposed L-NAME on insulin infusion for additional 2 weeks further increased SBP by 18 +/- 2 mmHg (from 157 +/- 2 to 175 +/- 2 mmHg). Plasma levels of NO metabolites (NOx) significantly decreased from 13.7 +/- 1.1 micromol/l during the control period to 6.1 +/- 0.6 micromol/l after 4 weeks of insulin infusion and further reduced to 4.1 +/- 0.5 micromol/l after combined infusion of L-NAME and insulin. L-NAME treatment alone for 2 weeks in control rats significantly increased SBP by 33 +/- 2 mmHg (from 133 +/- 2 to 166 +/- 2 mmHg) and plasma insulin levels, as a consequence of insulin resistance. Despite marked increases in blood pressure due to infusion of insulin alone or in combination with L-NAME, the sodium balance, urinary sodium and water excretions, water intake and body weight gain of insulin/L-NAME-treated rats were not significantly different from rats without insulin infusion.

CONCLUSIONS

Sustained hyperinsulinemia causes partial impairment of NO production that may contribute to the development of insulin resistance and hypertension. Additional inhibition of NO synthesis by L-NAME accentuates the blood pressure elevation and insulin resistance in hyperinsulinemic rats. Furthermore, a rightward shift of the renal arterial pressure-natriuretic function relationship occurred in this hypertensive model.

In vitro effect of hyperbaric oxygen on the chemolysis of infective stones

BACKGROUND

In order to extend the feasibility of hyperbaric oxygen therapy in the urological field, the present study aimed to investigate the dissolution activity of human infective stones in UROCITRA solution under hyperbaric oxygen condition.

METHODS

The dissolution activity of 7 struvite and 11 mixed struvite and carbonate apatite stones in UROCITRA solution were studied under 2.5 atmosphere (atm) hyperbaric oxygen (HBO) status in a Sigma I N-124 monoplace chamber. Another 7 struvite and 10 mixed struvite and carbonate apatite stones were also studied under normal condition. Chemolysis was performed in a drip device with a 150-ml/hour continuous flow rate.

RESULTS

Under 2.5 atm HBO status, the PO2 of UROCITRA solution was 365 +/- 44 mmHg, which was significantly higher than that of tap water (113 +/- 62 mmHg) and UROCITRA solution (125 +/- 12 mmHg) under normobaric condition (p < 0.001). The decreases in the stone weight of struvite under normobaric condition were 31 +/- 8.8% after 2 h and 48 +/- 15% after 4 h of treatment. The HBO-enriched UROCITRA solution did not increase the dissolution activity as reflected by comparable decreases in the dried stone weight (31.2 +/- 14.6% and 54 +/- 19% at the 2nd and 4th post-treatment hours, respectively, p > 0.05). Similarly, there was no significant difference in the percent stone weight decrease of the mixed struvite and carbonate apatite stones under either HBO or normobaric condition. The dissolution responsiveness of struvite was significantly greater than that of the mixed struvite and carbonate apatite stones.

CONCLUSIONS

The chemolysis of struvite in UROCITRA solution is significantly greater than that of the mixed struvite and carbonate apatite stones. However, the UROCITRA solution enriched with HBO does not enhance the dissolution of infective stones.

Ceramide inhibits lipopolysaccharide-mediated nitric oxide synthase and cyclooxygenase-2 induction in macrophages: effects on protein kinases and transcription factors

The goal of this study was to elucidate whether triggering the sphingomyelin pathway modulates LPS-initiated responses. For this purpose we investigated the effects of N-acetylsphingosine (C(2)-ceramide) on LPS-induced production of NO and PGE(2) in murine RAW 264.7 macrophages and explored the signaling pathways involved. We found that within a range of 10-50 microM, C(2)-ceramide inhibited LPS-elicited NO synthase and cyclooxygenase-2 induction accompanied by a reduction in NO and PGE(2) formation. By contrast, a structural analog of C(2)-ceramide that does not elicit functional activity, C(2)-dihydroceramide, did not affect the LPS response. The nuclear translocation and DNA binding study revealed that ceramide can inhibit LPS-induced NF-kappaB and AP-1 activation. The immunocomplex kinase assay indicated that IkappaB kinase activity stimulated by LPS was inhibited by ceramide, which concomitantly reduced the IkappaBalpha degradation caused by LPS within 1-6 h. In concert with the decreased cytosolic p65 protein level, LPS treatment resulted in rapid nuclear accumulation of NF-kappaB subunit p65 and its association with the cAMP-responsive element binding protein. Ceramide coaddition inhibited all the LPS responses. In addition, LPS-induced PKC and p38 mitogen-activated protein kinase activation were overcome by ceramide. In conclusion, we suggest that ceramide inhibition of LPS-mediated induction of inducible NO synthase and cyclooxygenase-2 is due to reduction of the activation of NF-kappaB and AP-1, which might result from ceramide's inhibition of LPS-stimulated IkappaB kinase, p38 mitogen-activated protein kinase, and protein kinase C.

Neonatal chemical sympathectomy attenuates fructose-induced hypertriglyceridemia and hypertension in rats

Experiments were performed to determine the pathogenic contribution of the peripheral sympathetic nervous system to fructose-induced hypertriglyceridemia, hyperinsulinemia and hypertension in rats. Neonatal chemical sympathectomy was performed in neonatal Sprague-Dawley rats (1-week old) by administration of guanethidine (50 microg/g, i.p.) 5 times per week for consecutive 3 weeks and nerve-intact rats were served as controls. Both groups of rats were fed a fructose-enriched diet for 9 weeks. The systolic blood pressure (SBP) and body weight were measured weekly and arterial blood samples were taken weekly for determinations of plasma insulin, glucose and triglyceride levels. The results showed that fructose feeding for one week significantly increased SBP in intact rats and sympathectomized rats (116+/-1 to 119+/-1 mmHg and 116+/-1 to 120+/-1 mmHg, respectively). SBP further increased thereafter in both groups. However, the increased SBP levels were significantly higher in intact group than in sympathectomized group after 5 weeks of fructose feeding. Fructose feeding for one week concurrently produced hypertriglyceridemia that preceded the appearance of hyperinsulinemia in both groups. The elevated plasma triglyceride levels were significantly lower in sympathectomized rats than in intact rats after 3 weeks of fructose feeding, whereas the elevated plasma insulin concentrations were not different between groups throughout fructose feeding period. Plasma glucose concentrations of both groups were comparable and remained unchanged throughout the study. These data indicate that neonatal chemical sympathectomy attenuated, but did not prevent, fructose-induced elevations in blood pressure and plasma triglyceride levels, suggesting a partial dependency of fructose-induced hypertriglyceridemia and hypertension on the integrity of the peripheral sympathetic nervous system (SNS) in rats.