The synergy of honokiol and fluconazole against clinical isolates of azole-resistant Candida albicans

AIMS

To evaluate the interaction of fluconazole (FLC) and honokiol (HNK) in vitro and vivo against azole-resistant (azole-R) clinical isolates of Candida albicans.

METHODS AND RESULTS

A checkerboard microdilution method was used to study the in vitro interaction of FLC and HNK in 24 azole-R clinical isolates of C. albicans. In vivo antifungal activity was performed to further analyse the interaction between FLC and HNK. In the in vitro study, synergism was observed in all 24 FLC-resistant strains tested as determined by fractional inhibitory concentration index (FICI), and in 22 strains by Delta E models. No antagonistic activity was observed in any of the strains tested. These positive interactions were also confirmed by using the time-killing test for the selected strain C. albicans YL371, which shows strong susceptible to the combination of HNK and FLC. In the in vivo study, the mice with candidiasis were treated successfully by a combination therapy of HNK with FLC, the results showed a decrease of the colony forming unit in infected and treated animals compared to the controls, at the conditions of the treatment used in this study.

CONCLUSIONS

Synergistic activity of HNK and FLC against clinical isolates of FLC-resistant C. albicans was observed in vitro and in vivo.

SIGNIFICANCE AND IMPACT OF THE STUDY

This report might provide a potential therapeutic method to overcome the problem of drug-resistance in C. albicans.

Relationship between response to risperidone, plasma concentrations of risperidone and CYP3A4 polymorphisms in schizophrenia patients

In this study, we examined the relationships between plasma concentrations of risperidone and 9-hydroxyrisperidone and polymorphisms of CYP3A4. All 130 schizophrenia patients (45 men, 85 women, age 15-60 years) who met DSM-IV criteria were given risperidone for 8 weeks. Clinical efficacy was determined using the Positive and Negative Syndrome Scale (PANSS). CYP3A4*1G was found to be associated with the change in total PANSS scores (Kruskal-Wallis test, P = 0.021), which was not significant on adjusting for multiple testing. Our study has, for the first time, conducted a genetic association study of the CYP3A4 gene with risperidone response. Further studies on larger groups and on the effects of the longer term risperidone treatment are needed to confirm these results.

Effects of sirolimus alone or in combination with cyclosporine A on renal ischemia/reperfusion injury

Calcineurin inhibitors exacerbate ischemic injury in transplanted kidneys, but it is not known if sirolimus protects or exacerbates the transplanted kidney from ischemic injury. We determined the effects of sirolimus alone or in combination with cyclosporin A (CsA) on oxygenated and hypoxic/reoxygenated rat proximal tubules in the following in vitro groups containing 6-9 rats per group: sirolimus (10, 50, 100, 250, 500, and 1000 nanog/mL); CsA (100 microg/mL); sirolimus (50 and 250 nanog/mL) + CsA (100 microg/mL); control; vehicle (20% ethanol). For in vivo studies, 3-week-old Wistar rats (150-250 g) were submitted to left nephrectomy and 30-min renal artery clamping. Renal function and histological evaluation were performed 24 h and 7 days after ischemia (I) in five groups: sham, I, I + SRL (3 mg x kg(-1) x day(-1), po), I + CsA (3 mg x kg(-1) x day(-1), sc), I + SRL + CsA. Sirolimus did not injure oxygenated or hypoxic/reoxygenated proximal tubules and did not potentiate the tubular toxic effects of CsA. Neither drug affected the glomerular filtration rate (GFR) at 24 h. GFR was reduced in CsA-treated rats on day 7 (0.5 +/- 0.1 mL/min) but not in rats receiving sirolimus + CsA (0.8 +/- 0.1 mL/min) despite the reduction in renal blood flow (3.9 +/- 0.5 mL/min). Acute tubular necrosis regeneration was similar for all groups. Sirolimus alone was not toxic and did not enhance hypoxia/reoxygenation injury or CsA toxicity to proximal tubules. Despite its hemodynamic effects, sirolimus protected post-ischemic kidneys against CsA toxicity.

Glyoxylate rather than ascorbate is an efficient precursor for oxalate biosynthesis in rice

Oxalate is widely distributed in the plant kingdom. While excess oxalate in food crops is detrimental to animal and human health, it may play various functional roles in plants, particularly for coping with environmental stresses. Understanding its biosynthetic mechanism in plants, therefore, becomes increasingly important both theoretically and practically. However, it is still a matter of debate as to what precursor and pathway are ultimately used for oxalate biosynthesis in plants. In this study, both physiological and molecular approaches were applied to address these questions. First, it was observed that when glycolate or glyoxylate was fed into detached leaves, both organic acids were equally effective in stimulating oxalate accumulation. In addition, the stimulation could be completely inhibited by cysteine, a glyoxylate scavenger that forms cysteine-glyoxylate adducts. To verify the role of glyoxylate further, various transgenic plants were generated, in which several genes involved in glyoxylate metabolism [i.e. SGAT (serine-glyoxylate aminotransferase), GGAT (glutamate-glyoxylate aminotransferase), HPR (hydroxypyruvate reductase), ICL (isocitrate lyase)], were transcriptionally regulated through RNAi or over-expression. Analyses on these transgenic plants consistently revealed that glyoxylate acted as an efficient precursor for oxalate biosynthesis in rice. Unexpectedly, it was found that oxalate accumulation was not correlated with photorespiration, even though this pathway is known to be a major source of glyoxylate. Further, when GLDH (L-galactono-1,4-lactone dehydrogenase), a key enzyme gene for ascorbate biosynthesis, was down-regulated, the oxalate abundance remained constant, despite ascorbate having been largely reduced as expected in these transgenic plants. Taken together, our results strongly suggest that glyoxylate rather than ascorbate is an efficient precursor for oxalate biosynthesis, and that oxalate accumulation and regulation do not necessarily depend on photorespiration, possibly due to the occurrence of the anaplerotic reaction that may compensate for glyoxylate formation in rice.

Combining maxRatio analysis with real-time PCR and its potential application for the prediction of Meloidogyne incognita in field samples

Diagnosing and quantifying plant-parasitic nematodes is critical for efficient nematode management. Several studies have been performed intending to demonstrate nematode quantification via real-time quantitative PCR. However, most of the studies used dilution of DNA templates to make standard curves, while few studies used samples with different nematode numbers to make the standard curve, resulting in a high standard error. The objective of the present study was to develop a high quality standard curve using samples containing different numbers of the root-knot nematode Meloidogyne incognita and evaluate the results of real time qPCR with maxRatio analysis. The results showed that a high quality standard curve was obtained with different nematode numbers using specific primers and cycle threshold (Ct)-PCR (R²=0.9962, P<0.001, n=9). With the maxRatio analysis, the fractional cycle number (FCN)-PCR cycle curve and adjusted FCN (FCNadj)-PCR cycle curve had similar patterns as those of the Ct-PCR cycle curve. For quantification of nematodes in field soil samples, qPCR estimations with a FCNadj-PCR cycle standard curve was very close to microscope counting of second-stage juveniles (R²=0.9064, P<0.001, n=10), qPCR estimations with a FCN-PCR cycle standard curve was comparably good (R²=0.8509, P<0.001, n=10), and the biases with a Ct-PCR cycle standard curve were large (R²=0.7154, P<0.001, n=10). Moreover, we found that the concentration of Triton X-100 had less of an effect on FCN as compared to Ct, with delta FCN 0.52, and delta Ct 3.94 at 0.8% Triton. The present study suggests, that combined with maxRatio methods, real time qPCR could be a practical approach for quantifying M. incognita in field samples.

AMP-activated protein kinase mediates activity-dependent regulation of peroxisome proliferator-activated receptor gamma coactivator-1alpha and nuclear respiratory factor 1 expression in rat visual cortical neurons

Nuclear respiratory factor 1 (NRF-1) is one of the key transcription factors implicated in mitochondrial biogenesis by activating the transcription of mitochondrial transcription factor A (mtTFA) and subunit genes of respiratory enzymes. NRF-1 transactivation activity can be enhanced by interaction with transcription coactivator peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha). The expression of PGC-1alpha, NRF-1 and mtTFA in neurons is known to be tightly regulated by neuronal activity. However, the coupling signaling mechanism is poorly understood. Here, we use primary cultures of rat visual cortical neurons and a rat model of monocular deprivation (MD) to investigate whether AMP-activated protein kinase (AMPK) is implicated in mediating activity-dependent regulation of PGC-1alpha and NRF-1 expression in neurons. We find that KCl depolarization rapidly activates AMPK and significantly increases PGC-1alpha, NRF-1, and mtTFA levels with increased ATP production in neuron cultures. Similarly, pharmacological activation of AMPK with 5'-aminoimidazole-4-carboxamide riboside (AICAR) or resveratrol also markedly increases PGC-1alpha and NRF-1 mRNA levels in neuron cultures. All these effects can be completely blocked by an AMPK inhibitor, Compound C. Conversely, 1 week of MD significantly reduces AMPK phosphorylation and activity, dramatically down-regulates PGC-1alpha and NRF-1 expression in deprived primary visual cortex. Administration of resveratrol in vivo significantly activates AMPK activity and attenuates the effects of MD on mitochondria by significant increase in PGC-1alpha and NRF-1 levels, mitochondria amount, and coupled respiration. These results strongly indicate that AMPK is an essential upstream mediator that couples neuronal activity to mitochondrial energy metabolism by regulation of PGC-1alpha-NRF-1 pathway in neurons.

Functional analysis of long-term outcome after Heller's myotomy for achalasia

Treatment of achalasia aims at reducing the pressure of the lower esophageal sphincter (LES) and palliate symptoms. Our objective in this study was to investigate functional changes of the esophagus after Heller myotomy and evaluate their influence on postoperative gastroesophageal reflux and esophageal morphologic changes. Between 1980 and 2003, 216 patients with achalasia underwent Heller myotomy, associated with anterior partial fundoplication (Dor fundoplication). Preoperative and long-term outcome data were collected from these patients at our hospital. The objective was to analyze esophageal functional results after Heller myotomy in the long term. Results were classified as excellent, good, fair, or poor, according to Vantrappen and Hellemans' modified classification. One-year, 2-year, 5-year, 10-year, and 20-year postoperative follow-up information was available in 100% of all patients, 91.7%, 85.1%, 60%, 52.6%, and 45.9%, respectively. There were no perioperative deaths. One year after the surgery, all patients had a significant reduction in symptoms of dysphagia and regurgitation. Five years, 10 years, 15 years, and 20 years after surgery, there were 77.2% of patients (142 in 184), 68.1%, 57.1%, and 54.5%, respectively, who were satisfied (excellent to good) with surgery. No esophageal peristalsis was demonstrated in patients during follow-up. Contractile waves in the body of the esophagus were simultaneous. The difference in the distal esophageal amplitude, the LES relaxation rate, and LES pressures in the anterior wall and/ or two sides was significant (P < 0.05) when compared before and after operation. However, there was no significant difference in the LES length and LES pressure in the posterior side. The change of direction of the LES pressure and the relaxation of LES correlate with long-term outcomes. Postoperative gastroesophageal reflux rates, including nocturnal reflux, increased with time. The percentage of patients whose esophageal diameter became normal or remained mildly increased with time in the first 10 years after surgery changed significantly. Myotomy is an effective way to palliate symptoms in patients with achalasia. Adequate myotomy can lead to reduction of LES pressure in two or three directions, which may facilitate esophageal emptying by gravity. Surgical intervention does not lead to the return of esophageal peristalsis. Functional damage of LES in patients with achalasia is irreversible.

Identification of Eya3 and TAC1 as long-day signals in the sheep pituitary

Seasonally breeding mammals such as sheep use photoperiod, encoded by the nocturnal secretion of the pineal hormone melatonin, as a critical cue to drive hormone rhythms and synchronize reproduction to the most optimal time of year. Melatonin acts directly on the pars tuberalis (PT) of the pituitary, regulating expression of thyrotropin, which then relays messages back to the hypothalamus to control reproductive circuits. In addition, a second local intrapituitary circuit controls seasonal prolactin (PRL) release via one or more currently uncharacterized low-molecular-weight peptides, termed "tuberalins," of PT origin. Studies in birds have identified the transcription factor Eya3 as the first molecular response activated by long photoperiod (LP). Using arrays and in situ hybridization studies, we demonstrate here that Eya3 is the strongest LP-activated gene in sheep, revealing a common photoperiodic molecular response in birds and mammals. We also demonstrate TAC1 (encoding the tachykinins substance P and neurokinin A) to be strongly activated by LP within the sheep PT. We show that these PRL secretagogues act on primary pituitary cells and thus are candidates for the elusive PT-expressed tuberalin seasonal hormone regulator.

Measurements of h(c)(1P(1)) in psi' decays

We present measurements of the charmonium state h(c)(1P(1)) made with 106x10(6) psi' events collected by BESIII at BEPCII. Clear signals are observed for psi'-->pi0 h(c) with and without the subsequent radiative decay h(c)-->gamma eta(c). First measurements of the absolute branching ratios B(psi'-->pi0 h(c)) = (8.4+/-1.3+/-1.0) x 10(-4) and B(h(c)-->gamma eta(c)) = (54.3+/-6.7+/-5.2)% are presented. A statistics-limited determination of the previously unmeasured h(c) width leads to an upper limit Gamma(h(c))<1.44 MeV (90% confidence). Measurements of M(h(c)) = 3525.40+/-0.13+/-0.18 MeV/c2 and B(psi'-->pi0 h(c)) x B(h(c)-->gamma eta(c)) = (4.58+/-0.40+/-0.50) x 10(-4) are consistent with previous results.

Effects of cigarette smoking and restraint stress on human colon tumor growth in mice

BACKGROUND

Cigarette smoking is a risk factor for colon cancer. Studies suggest that stress increases the incidence and promotes the development of cancers. Cigarette smoking and stress are closely associated, as people often smoke under stressful conditions and both of them can activate the adrenergic nervous system.

AIMS

To investigate the effects of cigarette smoking and restraint stress on colon cancer growth and the possible underlying mechanisms in these pathological processes.

METHODS

Nude mice bearing a HT-29 human colon cancer xenograft were either exposed to cigarette smoke and/or restraint stress. Cotinine and epinephrine levels in plasma of nude mice were measured by enzyme immunoassays. Expression of cyclooxygenase-2 (COX-2) and B-cell lymphoma-2 (Bcl-2) in tumor tissues were detected by Western blot. Prostaglandin E(2) (PGE(2)) concentrations were determined by enzyme immunoassay.

RESULTS

4% cigarette smoking together with restraint stress 1 h daily for 33 days promoted tumor growth in nude mice. This was accompanied by the increase of plasma levels of cotinine and epinephrine in these animals. They also enhanced the COX-2, Bcl-2 expressions and PGE(2) levels in tumor tissues.

CONCLUSION

These findings are important in understanding the pathogenesis of colon cancer, particularly related to cigarette smoking and stress.

The host defense peptide LL-37 activates the tumor-suppressing bone morphogenetic protein signaling via inhibition of proteasome in gastric cancer cells

The human cathelicidin LL-37, a pleiotropic host defense peptide, is down-regulated in gastric adenocarcinomas. We therefore investigated whether this peptide suppresses gastric cancer growth. LL-37 lowered gastric cancer cell proliferation and delayed G(1)-S transition in vitro and inhibits the growth of gastric cancer xenograft in vivo. In this connection, LL-37 increased the tumor-suppressing bone morphogenetic protein (BMP) signaling, manifested as an increase in BMP4 expression and the subsequent Smad1/5 phosphorylation and the induction of p21(Waf1/Cip1). The anti-mitogenic effect, Smad1/5 phosphorylation, and p21(Waf1/Cip1) up-regulation induced by LL-37 were reversed by the knockdown of BMP receptor II. The activation of BMP signaling was paralleled by the inhibition of chymotrypsin-like and caspase-like activity of proteasome. In this regard, proteasome inhibitor MG-132 mimicked the effect of LL-37 by up-regulating BMP4 expression and Smad1/5 phosphorylation. Further analysis of clinical samples revealed that LL-37 and p21(Waf1/Cip1) mRNA expressions were both down-regulated in gastric cancer tissues and their expressions were positively correlated. Collectively, we describe for the first time that LL-37 inhibits gastric cancer cell proliferation through activation of BMP signaling via a proteasome-dependent mechanism. This unique biological activity may open up novel therapeutic avenue for the treatment of gastric cancer.

Macroautophagy and ERK phosphorylation counteract the antiproliferative effect of proteasome inhibitor in gastric cancer cells

The ubiquitin-proteasome system and macroautophagy are two complementary pathways for protein degradation. Emerging evidence suggests that proteasome inhibition might be a promising approach for the treatment of cancer. In this study, we show that proteasome inhibitor MG-132 suppressed gastric cancer cell proliferation and induced macroautophagy. The induction of macroautophagy was evidenced by the formation of LC3(+) autophagosomes and the accumulation of acidic vesicular organelles and autolysosomes and was accompanied by the suppression of mammalian target of rapamycin complex 1 activity. Abolition of macroautophagy by knockdown of Class III phosphatidylinositol-3 kinase Vps34 or ATG5/7 sensitized gastric cancer cells to the antiproliferative effect of MG-132 by promoting G(2)/M cell cycle arrest. In addition, MG-132 increased ERK phosphorylation whose inhibition by MEK inhibitor significantly enhanced the antiproliferative effect of proteasome inhibition. To conclude, this study demonstrates that macroautophagy and ERK phosphorylation serve as protective mechanisms to counteract the antiproliferative effect of proteasome inhibition. This discovery may have implications for the application of proteasome-directed therapy for the treatment of cancer.

Antigen-dependent immunotherapy of non-obese diabetic mice with immature dendritic cells

Immunotherapy can be used to induce immunological tolerance by a number of different protocols. During the last decade the ability to use tolerogenic dendritic cells (DCs) to prevent autoimmunity has received much attention. Many studies have attempted to use immature or semi-mature DCs to induce tolerance in the non-obese diabetic (NOD) mouse model of human type 1 diabetes. However, most studies to date have used protocols in which generation of DCs involved a culture step in fetal bovine serum (FBS)-supplemented medium which may affect tolerance induction in a non-specific fashion. Indeed, several studies have shown that DCs cultured in the presence of FBS will induce a powerful T helper type 2 (Th2) immune response towards FBS-related antigens which can suppress an ongoing immune response. Hence, this may interfere with diabetes development in the NOD mouse by induction of immune deviation rather than by antigen-specific tolerance. In order to test whether antigen-specific tolerance induction by DC therapy is feasible in the NOD mouse, we therefore generated immature DCs using autologous serum [normal mouse serum (NMS)-supplemented cultures] instead of FBS, and we show that these DCs can protect NOD mice from diabetes, if pulsed with insulin-peptide antigens before adoptive transfer. Our data therefore support that DC therapy is able to prevent diabetes in the NOD mouse in an antigen-specific manner.