Isolation and characterization of SYN1, a RAD21-like gene essential for meiosis in Arabidopsis

The proper pairing, recombination, and segregation of chromosomes are central to meiosis and sexual reproduction. The syn1 mutation was previously identified as a synaptic mutant in a T-DNA-tagged population of plants. SYN1 has been isolated and found to exhibit similarity to Schizosaccharomyces pombe RAD21 and RAD21-like proteins, which are required for chromosome condensation and sister chromatid cohesion during mitosis. Plants homozygous for syn1 are male and female sterile and show defects in chromosome condensation and pairing beginning at leptonema of meiosis I. Fragmentation of the chromosomes was observed at metaphase I. Alternative promoters produced two SYN1 transcripts. One transcript was expressed at low levels in most tissues, whereas the other was expressed only in prebolting buds. DNA blot analyses suggest that Arabidopsis contains a small RAD21 gene family. Consistent with the DNA blot data, a second Arabidopsis RAD21-like gene has been identified. These results suggest that different RAD21-like proteins play essential roles in chromosome condensation and pairing during both meiosis and mitosis.

The nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model of childhood acute lymphoblastic leukemia reveals intrinsic differences in biologic characteristics at diagnosis and relapse

Acute lymphoblastic leukemia cells from 19 children, including 7 who remain in first complete remission (CR1), were engrafted into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. High-level infiltration of bone marrow, spleen, and liver was observed, with variable infiltration of other organs. The immunophenotypes of xenografts were essentially unaltered compared with the original patient sample. In addition, sequencing of the entire p53 coding region revealed no mutations in 14 of 14 xenografts (10 from patients at diagnosis and 4 at relapse). Cells harvested from the spleens of engrafted mice readily transferred the leukemia to secondary and tertiary recipients. To correlate biologic characteristics of xenografts with clinical and prognostic features of the patients, the rates at which individual leukemia samples engrafted in NOD/SCID mice were analyzed. Differences in biologic correlates were encountered depending on stage of disease: a direct correlation was observed between the rate of engraftment and length of CR1 for samples harvested at relapse (r = 0.96; P =.002), but not diagnosis (r = 0.38; P =.40). In contrast, the in vivo responses of 6 xenografts to vincristine showed a direct correlation (r = 0.96; P =.002) between the length of CR1 and the rate at which the leukemia cell population recovered following vincristine treatment, regardless of whether the xenografts were derived from patients at diagnosis or relapse. This study supports previous findings that the NOD/SCID model of childhood ALL provides an accurate representation of the human disease and indicates that it may be of value to predict relapse and design alternative treatment strategies in a patient-specific manner.

L-arabinose selectively inhibits intestinal sucrase in an uncompetitive manner and suppresses glycemic response after sucrose ingestion in animals

The objective of this study was to investigate the effects of L-arabinose on intestinal alpha-glucosidase activities in vitro and to evaluate its effects on postprandial glycemic responses in vivo. L-Arabinose inhibited the sucrase activity of intestinal mucosa in an uncompetitive manner (Ki, 2 mmol/L). Neither the optical isomer D-arabinose nor the disaccharide L-arabinobiose inhibited sucrase activity, whereas D-xylose was as potent as L-arabinose in inhibiting this activity. L-Arabinose and D-xylose showed no inhibitory effect on the activities of intestinal maltase, isomaltase, trehalase, lactase, and glucoamylase, or pancreatic amylase. In contrast, a known alpha-glucosidase inhibitor, acarbose, competitively inhibited (Ki, 1.1 mumol/L) sucrase activity and also inhibited intestinal maltase, glucoamylase, and pancreatic amylase. L-Arabinose suppressed the increase of blood glucose after sucrose loading dose-dependently in mice (ED50, 35 mg/kg), but showed no effect after starch loading. The suppressive effect of D-xylose on the increase of blood glucose after sucrose loading was 2.4 times less than that of L-arabinose, probably due to intestinal absorption of the former. Acarbose strongly suppressed glycemic responses in both sucrose loading (ED50, 1.1 mg/kg) and starch loading (ED50, 1.7 mg/kg) in mice. L-Arabinose suppressed the increase of plasma glucose and insulin in rats after sucrose loading, the suppression of the former being uninterruptedly observed in mice for 3 weeks. Thus, the results demonstrated that L-arabinose selectively inhibits intestinal sucrase activity in an uncompetitive manner and suppresses the glycemic response after sucrose ingestion by inhibition of sucrase activity.

Antioxidative activities of several marine polysaccharides evaluated in a phosphatidylcholine-liposomal suspension and organic solvents

The antioxidative activities of several water-soluble marine polysaccharides, alginate (ALG), alginate sulfate (SALG), propylene glucolalginate sodium sulfate (PSS), propylene glucol mannuronate sulfate (PGMS), the oligosaccharide of chitosan (OLC), N,O-carboxymethyl chitosan (NOCC) and hydroxypropylated chitosan (HPC), were examined in a phosphatidylcholine (PC)-liposomal suspension containing the water-soluble radical emitter, 2,2'-azobis (2-amidinopropane) dihydrochloride. In the suspensions containing OLC and SALG, the initial rates of PC-OOH accumulation were 2.78 x 10(-8) MS-1 and 2.88 x 10(-8) MS-1, respectively, while all the polysaccharides tested showed antioxidative activity. Liposoluble marine polysaccharides, hexanoyl chitin (HCH) and an N-benzoylhexanoyl chitosan (NBHC) solution, also retarded the hydroperoxide accumulation of methyl linoleate by effectively trapping peroxide radicals in organic solvents when the radical chain reaction had been initiated by 2,2'-azobis (2,4-dimethylvaleronitrile). The kinetic data presented indicate that the alginate and chitin derivatives can be expected to play a role in the antioxidative mechanism of biological systems.

The p53 pathway and its inactivation in neuroblastoma

Early studies of p53 in neuroblastoma reported infrequent mutations in tumours and cell lines. Cytoplasmic sequestration was later proposed as an alternative mechanism of inactivation, but many studies have since reported an intact p53 pathway in neuroblastoma cell lines, as detected by nuclear p53 accumulation after DNA damage, intact DNA binding, transcriptional activation of target genes and the induction of apoptosis. In some MYCN amplified cell lines however, an irradiation induced G(1) arrest does not occur, despite the presence of normal p53. Neuroblastoma usually responds to chemotherapy but frequently relapses, and there is evidence from tumours, and cell lines that p53 inactivation via mutation or MDM2 amplification occurs at relapse and is sometimes associated with multidrug resistance. If p53 inactivation occurs frequently in relapsed tumours it may be appropriate to include p53 independent therapies in the initial management of high-risk neuroblastoma.

Characterization of a Tembusu virus isolated from naturally infected house sparrows (Passer domesticus) in Northern China

The house sparrow (Passer domesticus) is one of the most widely distributed wild birds in China. Tembusu virus (TMUV) strain, TMUV-SDHS, was isolated from house sparrows living around the poultry farms in Shandong Province, Northern China. Genetic analysis of E and NS5 genes showed that it had a close relationship with that of the YY5 strain, which can cause severe egg drop in ducks. Pathogenicity studies showed that the virus is highly virulent when experimentally inoculated into the ducks. These findings show that house sparrows carrying the Tembusu virus may play an important role in transmitting the virus among other species.

Chronic hypoxia upregulates endothelial and inducible NO synthase gene and protein expression in rat lung

The effect of chronic hypoxia-induced pulmonary hypertension on nitric oxide synthase (NOS) in the lung is controversial. To clarify the regulation of endothelial and inducible NOS (eNOS and iNOS) expression in the chronically hypoxic lung, Northern and Western blot analyses were performed on mRNA and total protein from lungs of rats exposed to 3 wk of hypoxia (10% O2, normobaric) or normoxia. Expression of the mRNA and protein for eNOS was significantly increased (1.6-fold and 2.1-fold, respectively) by hypoxia. Immunohistochemistry with an isoform-specific antibody demonstrated de novo expression of eNOS in the endothelium of resistance vessels in the pulmonary vasculature of the hypoxic rats. eNOS was detected in the endothelium of large vessels in both normoxic and hypoxic rat lungs. The level of mRNA and protein for iNOS was also found to be significantly increased (1.9-fold and 1.4-fold, respectively). In addition to the 4.4-kilobase (kb) iNOS mRNA species, a novel 4.0-kb species was also induced by hypoxia. We conclude that expression of eNOS and iNOS was increased in the lungs of rats subjected to chronic hypoxia, and that there was de novo expression of eNOS protein in the microvascular endothelium.

ABCC multidrug transporters in childhood neuroblastoma: clinical and biological effects independent of cytotoxic drug efflux

Background

Although the prognostic value of the ATP-binding cassette, subfamily C (ABCC) transporters in childhood neuroblastoma is usually attributed to their role in cytotoxic drug efflux, certain observations have suggested that these multidrug transporters might contribute to the malignant phenotype independent of cytotoxic drug efflux.

Methods

A v-myc myelocytomatosis viral related oncogene, neuroblastoma derived (MYCN)–driven transgenic mouse neuroblastoma model was crossed with an Abcc1-deficient mouse strain (658 hMYCN^1/−, 205 hMYCN^+/1 mice) or, alternatively, treated with the ABCC1 inhibitor, Reversan (n = 20). ABCC genes were suppressed using short interfering RNA or overexpressed by stable transfection in neuroblastoma cell lines BE(2)-C, SH-EP, and SH-SY5Y, which were then assessed for wound closure ability, clonogenic capacity, morphological differentiation, and cell growth. Real-time quantitative polymerase chain reaction was used to examine the clinical significance of ABCC family gene expression in a large prospectively accrued cohort of patients (n = 209) with primary neuroblastomas. Kaplan–Meier survival analysis and Cox regression were used to test for associations with event-free and overall survival. Except where noted, all statistical tests were two-sided.

Results

Inhibition of ABCC1 statistically significantly inhibited neuroblastoma development in hMYCN transgenic mice (mean age for palpable tumor: treated mice, 47.2 days; control mice, 41.9 days; hazard ratio [HR] = 9.3, 95% confidence interval [CI] = 2.65 to 32; P < .001). Suppression of ABCC1 in vitro inhibited wound closure (P < .001) and clonogenicity (P = .006); suppression of ABCC4 enhanced morphological differentiation (P < .001) and inhibited cell growth (P < .001). Analysis of 209 neuroblastoma patient tumors revealed that, in contrast with ABCC1 and ABCC4, low rather than high ABCC3 expression was associated with reduced event-free survival (HR of recurrence or death = 2.4, 95% CI = 1.4 to 4.2; P = .001), with 23 of 53 patients with low ABCC3 expression experiencing recurrence or death compared with 31 of 155 patients with high ABCC3. Moreover, overexpression of ABCC3 in vitro inhibited neuroblastoma cell migration (P < .001) and clonogenicity (P = .03). The combined expression of ABCC1, ABCC3, and ABCC4 was associated with patients having an adverse event, such that of the 12 patients with the “poor prognosis” expression pattern, 10 experienced recurrence or death (HR of recurrence or death = 12.3, 95% CI = 6 to 27; P < .001).

Conclusion

ABCC transporters can affect neuroblastoma biology independently of their role in chemotherapeutic drug efflux, enhancing their potential as targets for therapeutic intervention.

Induction of nitric oxide synthase in the human cardiac allograft is associated with contractile dysfunction of the left ventricle

BACKGROUND

The mechanisms underlying cardiac contractile dysfunction after transplantation remain poorly defined. Previous work has revealed that inducible nitric oxide synthase (iNOS) is expressed in the rat heterotopic cardiac allograft during rejection; resultant overproduction of nitric oxide (NO) might cause cardiac contractile dysfunction via the negative inotropic and cytotoxic actions of NO. In this investigation, we tested the hypothesis that induction of iNOS may occur and be associated with cardiac allograft contractile dysfunction in humans.

METHODS AND RESULTS

We prospectively studied 16 patients in the first year after cardiac transplantation at the time of serial surveillance endomyocardial biopsy. Clinical data, the results of biopsy histology, and echocardiographic and Doppler evaluation of left ventricular systolic and diastolic function were recorded. Total RNA was extracted from biopsy specimens, and mRNA for beta-actin, detected by reverse transcription-polymerase chain reaction (RT-PCR) using human specific primers, was used as a constitutive gene control; iNOS mRNA was similarly detected by RT-PCR using human specific primers. iNOS protein was detected in biopsy frozen sections by immunofluorescence. Myocardial cGMP was measured by radioimmunoassay, and serum nitrogen oxide levels (NOx = NO2 + NO3) were measured by chemiluminescence. iNOS mRNA was detected in allograft myocardium at some point in each patient and in 59 of 123 biopsies (48%) overall. In individual patients, iNOS mRNA expression was episodic and time dependent; the frequency of expression was highest during the first 180 days after transplant (P = .0006). iNOS protein associated with iNOS mRNA was detected by immunofluorescence in cardiac myocytes. iNOS mRNA expression was not related to the ISHLT histological grade of rejection or to serum levels of NOx but was associated with increased levels of myocardial cGMP (P = .01) and with both systolic (P = .024) and diastolic (P = .006) left ventricular contractile dysfunction measured by echocardiography and Doppler.

CONCLUSIONS

These data support a relation between iNOS mRNA expression and contractile dysfunction in the human cardiac allograft.

Immunohistochemical localization of 3',5'-cyclic guanosine monophosphate in the canine proximal colon: responses to nitric oxide and electrical stimulation of enteric inhibitory neurons

There is growing evidence that nitric oxide serves as a neurotransmitter released from enteric inhibitory nerves in the gastrointestinal tract. The distribution of nitric oxide synthase suggests that nitric oxide may also be a neurotransmitter within enteric ganglia. Since many actions of nitric oxide are mediated by stimulation of soluble guanylate cyclase and a subsequent increase in 3',5'-cyclic guanosine monophosphate (cGMP) concentration, targets for nitric oxide in the canine proximal colon were investigated by immunohistochemical localization of cGMP. In the presence of phosphodiesterase inhibitors (M&B 22948, 100 microM and 3-isobutyl-1-methyl-xanthine, 1 mM), exogenous nitric oxide and electrical field stimulation caused an accumulation of cGMP-like immunoreactivity in several cell-types including colonic smooth muscle cells. cGMP-like immunoreactivity was also observed in a subpopulation of neurons in both myenteric and submucosal ganglia. Sequential labeling with the NADPH diaphorase technique showed that 94% of neurons that responded to exogenous nitric oxide with an increase in cGMP-like immunoreactivity were NADPH diaphorase negative. None of the myenteric neurons that responded to electrical field stimulation with an increase in cGMP-like immunoreactivity were NADPH diaphorase positive, and only one submucosal neuron with cGMP-like immunoreactivity was also NADPH diaphorase positive. The electrical field-stimulated increase in cGMP-like immunoreactivity was blocked by nitroarginine (100 microM). An increase in cGMP-like immunoreactivity also occurred in interstitial cells located at the submucosal surface of the circular muscle layer. These cells are interposed between nerve varicosities and smooth muscle cells and may partially mediate neuromuscular transmission. Sodium nitroprusside and nitric oxide also caused an accumulation of cGMP-like immunoreactivity in smooth muscle cells of intramural arterioles and venules. The results of this study further support the role of nitric oxide as a neurotransmitter in colonic muscles, and provide support for the hypothesis that interstitial cells are functionally innervated by enteric inhibitory neurons. The data also suggest that nitric oxide may serve as a neurotransmitter in enteric ganglia.

Upregulation of nitric oxide synthase correlates temporally with onset of pulmonary vascular remodeling in the hypoxic rat

Alterations in nitric oxide signaling have been hypothesized to have an etiologic role in the development of hypoxic pulmonary hypertension. However, changes in the expression of nitric oxide synthase (NOS) in hypoxic lungs remains controversial. In this study, we used (1) Northern and Western analyses to measure NOS mRNA and protein expressions, (2) lung histology together with measurements of lung and heart weights to monitor pulmonary vascular remodeling, and (3) immunohistochemistry to localize NOS proteins. The data demonstrated that endothelial NOS mRNA and protein were upregulated over 1 to 7 days of hypoxia that temporally correlated with and preceded the vascular remodeling that occurred in the course of the development of hypoxic pulmonary hypertension. Hypoxia also induced brain NOS in bronchial epithelium and inducible NOS in vascular smooth muscle but did not affect inducible NOS expression in macrophages or basal guanylyl cyclase activity in the lung. These findings showed that upregulation of endothelial NOS was tightly correlated with the vascular remodeling induced by hypoxia, suggesting a role for nitric oxide in the development of pulmonary hypertension.

Conditional abatement of tissue fibrosis using nucleoside analogs to selectively corrupt DNA replication in transgenic fibroblasts

Progressive tissue fibrosis can compromise epithelial function resulting in organ failure. Appreciating evidence suggests that fibroblasts provide fibrogenic collagens during such injury. We further tested this notion by attempting to reduce the physiologic consequences of organ fibrosis through the selective killing of fibroblasts at sites of injury. Here, we report the conditional reduction of tissue fibroblasts using the coding sequence for herpesvirus thymidine kinase (DeltaTK) put under the control of a cell-specific promoter from the gene encoding fibroblast-specific protein 1 (FSP1). Transgenic fibroblasts from mice carrying FSP1.DeltaTK minigenes expressed thymidine kinase concordantly with native FSP1 and, compared to transgenic epithelium, were selectively susceptible to the lethal effects of nucleoside analogs either in culture or during experimental renal fibrosis. The numbers of fibroblasts in fibrogenic kidney tissue were reduced on exposure to nucleoside analogs as was the degree of type I collagen deposition and the extent of fibrosis. Fibroblast reduction following the stress of DNA chain termination highlights the important contribution of cell division during fibrogenesis. Our findings convey a proof of principle regarding the importance of FSP1(+) fibroblasts in fibrosis as well as providing a new approach to treating the relentless scarification of tissue.

Small-molecule multidrug resistance-associated protein 1 inhibitor reversan increases the therapeutic index of chemotherapy in mouse models of neuroblastoma

The multidrug resistance-associated protein 1 (MRP1) has been closely linked to poor treatment response in several cancers, most notably neuroblastoma. Homozygous deletion of the MRP1 gene in primary murine neuroblastoma tumors resulted in increased sensitivity to MRP1 substrate drugs (vincristine, etoposide, and doxorubicin) compared with tumors containing both copies of wild-type MRP1, indicating that MRP1 plays a significant role in the drug resistance in this tumor type and defining this multidrug transporter as a target for pharmacologic suppression. A cell-based readout system was created to functionally determine intracellular accumulation of MRP1 substrates using a p53-responsive reporter as an indicator of drug-induced DNA damage. Screening of small-molecule libraries in this readout system revealed pyrazolopyrimidines as a prominent structural class of potent MRP1 inhibitors. Reversan, the lead compound of this class, increased the efficacy of both vincristine and etoposide in murine models of neuroblastoma (syngeneic and human xenografts). As opposed to the majority of inhibitors of multidrug transporters, Reversan was not toxic by itself nor did it increase the toxicity of chemotherapeutic drug exposure in mice. Therefore, Reversan represents a new class of nontoxic MRP1 inhibitor, which may be clinically useful for the treatment of neuroblastoma and other MRP1-overexpressing drug-refractory tumors by increasing their sensitivity to conventional chemotherapy.

Long-term follow-up of a phase III study comparing radiotherapy with or without weekly oxaliplatin for locoregionally advanced nasopharyngeal carcinoma

BACKGROUND

Previous results from our trial showed that adding oxaliplatin to radiotherapy (RT) increased survival in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) at 2 years. Here, we present the data of long-term efficacy and late toxic effects.

PATIENTS AND METHODS

Between January 2001 and January 2003, 115 Patients with nonkeratinizing/undifferentiated locoregionally advanced NPC were randomly to receive either RT alone (n = 56) or plus concurrent oxaliplatin 70 mg/m(2) weekly for six cycles (n = 59).

RESULTS

After a median follow-up of 114 months (range 18-139 months), the 5-year overall survival (OS) and metastasis-free survival (MFS) rates in the concurrent chemoradiotherapy (CCRT) group were significantly higher than those observed in the RT-alone group (OS, 73.2% versus 60.2%, P = 0.028; MFS, 74.7% versus 63.0%, P = 0.027). However, CCRT did not improve locoregional failure-free survival significantly. Subgroup analyses showed that the superiorities of CCRT mainly existed in the T3-4N0-1 stage subgroup (OS: HR = 0.394, P = 0.034). The grade 3/4 late toxic effects were similar in the two groups.

CONCLUSION(S)

The long-term follow-up data confirms the role of CCRT as a treatment of locoregionally advanced NPC. Oxaliplatin can be considered as an alternative optional therapeutic regimen for these patients due to its high efficiency and low toxic effect.

Direct and coordinate regulation of ATP-binding cassette transporter genes by Myc factors generates specific transcription signatures that significantly affect the chemoresistance phenotype of cancer cells

Increased expression of specific ATP-binding cassette (ABC) transporters is known to mediate the efflux of chemotherapeutic agents from cancer cells. Therefore, establishing how ABC transporter genes are controlled at their transcription level may help provide insight into the role of these multifaceted transporters in the malignant phenotype. We have investigated ABC transporter gene expression in a large neuroblastoma data set of 251 tumor samples. Clustering analysis demonstrated a strong association between differential ABC gene expression patterns in tumor samples and amplification of the MYCN oncogene, suggesting a correlation with MYCN function. Using expression profiling and chromatin immunoprecipitation studies, we show that MYCN oncoprotein coordinately regulates transcription of specific ABC transporter genes, by acting as either an activator or a repressor. Finally, we extend these notions to c-MYC showing that it can also regulate the same set of ABC transporter genes in other tumor cells through similar dynamics. Overall our findings provide insight into MYC-driven molecular mechanisms that contribute to coordinate transcriptional regulation of a large set of ABC transporter genes, thus affecting global drug efflux.

Expression of nitric oxide synthase immunoreactivity by interstitial cells of the canine proximal colon

A subpopulation of interstitial cells (ICs) are interposed between nerve terminals and smooth muscle cells in the gastrointestinal tract and may participate in neuromuscular transmission. These cells appear to be targets for NO released from enteric inhibitory nerves and respond to exogenous NO with: (i) an elevation in cGMP levels; (ii) an increase in intracellular Ca2+; (iii) and release of a diffusible substance that has tentatively been identified as NO. For the latter to be possible, ICs must express a constitutive isoform of NOS. This study characterized the expression of NOS-like immunoreactivity (NOS-LI) in ICs of the canine colon using 3 antibodies raised against the 2 known constitutive forms of NOS (i.e., neural (nNOS) and endothelial (eNOS) isoforms). Antibodies raised against cNOS and an antibody raised against rat cerebellar nNOS labeled ICs along the submucosal surface of the circular muscle layer (IC-SM), along the surface of septa that separate the circular muscle into fiber bundles (IC-SM), and in the myenteric region between the circular and longitudinal muscle layers (IC-MY). Another antibody raised against rat cerebellar nNOS failed to label ICs. Cultured IC-SM also expressed NOS-LI, suggesting that this feature of the IC phenotype survives culture conditions. Arteriolar endothelial cells in the canine colon were labeled with the same 2 antibodies that labeled ICs, suggesting there are significant structural similarities between NO synthases in ICs and endothelial cells. The data suggest that IC-SM and IC-MY express a constitutive form of NOS. Synthesis of NO by ICs may influence electrical rhythmicity and may serve to amplify and even propagate enteric inhibitory neurotransmission.

Localization of endothelial NOS at the basal microtubule membrane in ciliated epithelium of rat lung

Nitric oxide (NO), an important cell messenger molecule, is formed endogenously in the lung airway. Three individual genes of NO synthase (NOS), which represent brain NOS (bNOS), inducible NOS (iNOS), and endothelial NOS (eNOS), have been reported in the cultured lung epithelium. Although studies in vivo showed that bNOS and iNOS were expressed and localized in the cytoplasm of bronchial epithelium, the expression and localization of eNOS remains to be determined. Therefore, we employed an eNOS monoclonal antibody whose immunospecificity was tested by both Western blot and preadsorption immunohistochemistry to immunostain rat lungs from fetus to adult. The results showed that eNOS immunoreactivity began to appear in the lung epithelium within 2 hr after birth. Six hours later (8 hr after birth), the NOS immunoreaction was concentrated near the surface of the ciliated epithelial cells. This staining pattern appeared in lungs at Day 1, Week 1, Week 2, and in adult rats. By electron microscopy, eNOS immunoreactivity was confirmed within ciliated epithelium and was shown to be associated with the basal microtubule membrane of the cilia. Nonciliated cells were not stained. Type II epithelial cells also contain eNOS immunoreactivity, which is primarily associated with rough endoplasmic reticulum, and free ribosomes. However, macrophages in the lungs lacked eNOS immunoreactivity. This study demonstrated that eNOS was postnatally expressed in rat bronchial ciliated epithelium. The localization of eNOS at the basal membrane of ciliary microtubules suggests that eNOS may be involved in the function of epithelial cilia, consistent with previous physiological studies.

Genes associated with membrane-initiated signaling of estrogen and energy homeostasis

During the reproductive cycle, fluctuations in circulating estrogens affect multiple homeostatic systems controlled by hypothalamic neurons. Two of these neuronal populations are arcuate proopiomelanocortin and neuropeptide Y neurons, which control energy homeostasis and feeding. Estradiol modulates these neurons either through the classical estrogen receptors (ERs) to control gene transcription or through a G protein-coupled receptor (mER) activating multiple signaling pathways. To differentiate between these two divergent ER-mediated mechanisms and their effects on homeostasis, female guinea pigs were ovariectomized and treated systemically with vehicle, estradiol benzoate (EB) or STX, a selective mER agonist, for 4 wk, starting 7 d after ovariectomy. Individual body weights were measured after each injection day for 28 d, at which time the animals were euthanized, and the arcuate nucleus was microdissected. As predicted, the body weight gain was significantly lower for EB-treated females after d 5 and for STX-treated females after d 12 compared with vehicle-treated females. Total arcuate RNA was extracted from all groups, but only the vehicle and STX-treated samples were prepared for gene microarray analysis using a custom guinea pig gene microarray. In the arcuate nucleus, 241 identified genes were significantly regulated by STX, several of which were confirmed by quantitative real-time PCR and compared with EB-treated groups. The lower weight gain of EB-treated and STX-treated females suggests that estradiol controls energy homeostasis through both ERalpha and mER-mediated mechanisms. Genes regulated by STX indicate that not only does it control neuronal excitability but also alters gene transcription via signal transduction cascades initiated from mER activation.

Chronic inhaled nitric oxide: effects on pulmonary vascular endothelial function and pathology in rats

Nitric oxide (NO) is a potent endogenous vasodilator produced in endothelial cells. Inhaled NO selectively vasodilates the pulmonary circulation. We determined the effects of chronic inhaled NO on hypoxic pulmonary vascular remodeling and endothelium NO-dependent and -independent vasodilation during normoxic and hypoxic conditions in rats. Rats were exposed to 3 wk of normoxia (N), normoxia + 20 ppm inhaled NO (N+NO), chronic hypoxia with 10% normobaric oxygen (CH), or CH and 20 ppm inhaled NO (CH+NO). Inhaled NO decreased the number of muscular pulmonary arteries, the medial smooth muscle thickness, and the right ventricular hypertrophy associated with chronic hypoxia but had no effect on these parameters in normoxic rats. All groups were evaluated with isolated perfused lungs. The pulmonary artery pressure increased by the same amount in the CH and CH+NO rats compared with N rats. Inhibition of NO synthase with N omega-nitro-L-arginine methyl ester (L-NAME) caused greater pulmonary vasoconstriction in CH (19.2 +/- 3.7 mmHg) vs. N (7.8 +/- 3.0 mmHg) and less in CH+NO (9.1 +/- 0.8 mmHg) vs. CH rats. Bradykinin (3 micrograms) caused greater vasodilation in CH (76 +/- 12%) vs. N (29 +/- 5%) but significantly less in CH+NO (41 +/- 11%) vs. CH rats. Vasodilation with acute inhaled NO (40 ppm) was no different in CH vs. N rats but was lower in CH+NO (19 +/- 5%) vs. CH (34 +/- 6%) rats. This study demonstrates that chronic inhaled NO attenuates hypoxic pulmonary vascular remodeling. Furthermore, these results suggest that chronic inhaled NO decreases endothelium NO-dependent and -independent vasodilation.

Phase II study of sorafenib in combination with cisplatin and 5-fluorouracil to treat recurrent or metastatic nasopharyngeal carcinoma

BACKGROUND

We aimed to investigate the efficacy and tolerability of sorafenib combined with cisplatin and 5-fluorouracil (5-FU) in patients with recurrent or metastatic nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

It was a Simon two-stage designed trial. Chemotherapy-naive patients with recurrent or metastatic disease were enrolled. The regimen was sorafenib 400 mg orally b.i.d., cisplatin 80 mg/m(2) i.v. day 1, and 5-FU 1000 mg/m(2)/day CIV for 4 days, repeated every 21 days. After a maximum of six cycles of chemotherapy, patients received maintenance of sorafenib.

RESULTS

In total, 54 patients were enrolled. The objective response rate reached 77.8%, including 1 complete response and 41 partial responses. The median progression-free survival was 7.2 months (95% CI 6.8-8.4 months), and the median overall survival was 11.8 months (95% CI 10.6-18.7 months). Major toxic effects included hand-foot skin reaction, myelosuppression, and gastrointestinal (GI) reaction. The incidence of hemorrhage was 22.2%, and one patient with liver metastases died of GI bleeding. Contrast-enhanced ultrasonography was carried out in a subset of patients with liver metastases.

CONCLUSION

Combination of sorafenib, cisplatin (80 mg/m(2)) and 5-FU (3000 mg/m(2)) was tolerable and feasible in recurrent or metastatic NPC. Further randomized trials to compare sorafenib plus cisplatin and 5-FU with standard dose of cisplatin plus 5-FU in NPC are warranted.