Model-guided extraction of coronary vessel structures in 2D X-ray angiograms

Analysis of vessel structures in 2D X-ray angiograms is important for pre-operative evaluation and image-guided intervention. However, automated vessel segmentation in angiograms, especially extraction of the topology such as bifurcations and vessel crossings, remains challenging mainly due to the projective nature of angiography and background clutter. In this paper, a novel framework for model-guided coronary vessel extraction in 2D angiograms is presented. In this framework, a graph is constructed using a sparse set of pixels in the angiogram. With a single user-supplied click as the starting point, the vessel tree structure in the angiogram is automatically extracted from the graph. Ambiguities in this tree structure caused by 3D-to-2D projection are then resolved using topological information from the 3D vessel model of the same patient. By incorporating this prior shape information, the proposed method is effective in extraction of vessel topology, and is robust to background clutter and uneven illumination. Through quantitative evaluation on 20 angiograms, it is shown that this model-guided approach significantly improves detection of vessel structures and bifurcations.

Cell proliferation and apoptosis in the fetal and neonatal ovary of guinea pigs

The guinea pig is an excellent animal model for studying reproductive biology of adult humans and most domestic animals. Yet, whether this animal might serve as a good model for embryonic stage investigations and determinations of signals affecting or directing ovary development remains unknown. These questions were addressed by examining morphological evolution and the expression of biomarkers of cell proliferation and apoptosis in the ovaries of fetal and neonatal guinea pigs in the present study. Embryonic and neonatal guinea pigs at 30, 40, 50, 60, and 68 days postcoitum (dpc) and at 1 day postpartum (dpp) were evaluated, and the dynamic changes in follicles between 30 dpc and 1 dpp were observed. Results also showed that a critical period of follicular development in guinea pig embryos occurred at 40 to 50 dpc. Moreover, the proliferating-cell nuclear antigen, a cell proliferation marker, immunohistochemically stained healthy follicles, while caspase-3, an apoptosis marker, was mainly observed in atretic follicles. Together, these results demonstrate that cell proliferation and apoptosis contribute to follicular formation, development, and atresia in fetal and neonatal guinea pig ovaries. Furthermore, this study confirmed that the guinea pig is also an excellent animal model for studying reproductive biology in human and domestic animal embryos.

Interspecies difference of luteolin and apigenin after oral administration of Chrysanthemum morifolium extract and prediction of human pharmacokinetics

The aims of the present study were to study the interspecies difference in the pharmacokinetics of luteolin and apigenin occurring in Chrysanthemum morifolium extract (CME) among rats, beagle dogs, mini-pigs, and humans, and compared the human pharmacokinetic parameters with the data predicted from the above three animals. The plasma concentrations of luteolin and apigenin were determined with a RP-HPLC method. An interspecies difference of pharmacokinetics was found, especially between rats and other species, the plasma concentration of luteolin was much lower than that of apigenin in rats, although the content of luteolin in CME was higherthan that of apigenin, whereas the plasma concentration of luteolin was much higher than that of apigenin in dogs, mini-pigs and humans. Animal scale-up of some pharmacokinetic parameters of luteolin and apigenin were also performed after rats, beagle dogs, mini-pigs and humans were orally given CME at dosages of 400 mg/kg, 102 mg/kg, 90 mg/kg, and 20 mg/kg, respectively. Linear relationships were obtained between log mean retention time (MRT) and log species body weight (W) (kg), and log elimination half-life (t1/2) (h) and logW. The corresponding allometric equations were MRT=9.382W(0.1711) (R2 = 0.9999) and t1/2 = 4.811W(0.1093) (R2 = 0.9013) for luteolin, MRT = 12.53W(0.0356) (R2 = 0.9980) and t1/2 = 7.940W(0.0294) (R2 = 0.9258) for apigenin, respectively. The predicted human pharmacokinetic parameters (MRT and t1/2) by an allometric approach were 18.6 h and 7.46 h for luteolin, 14.3 h and 8.95 h for apigenin, respectively, which were close to the values obtained from humans (20 mg CME/kg) in the present study. The study has demonstrated the possibility to extrapolate the pharmacokinetic behavior of flavonoids from animals to humans.

Diagnosis of ovarian metastasis from gestational trophoblastic neoplasia by 3D power Doppler ultrasound and dynamic contrast-enhanced magnetic resonance imaging: case report

Choriocarcinoma is a highly malignant disease of trophoblastic cells, which affects young women in the reproductive years. The main sites of metastasis from choriocarcinoma are lung, vagina, liver, gastrointestinal tract and kidneys, and the involvement of the ovaries is extremely rare. The diagnosis of ovarian metastasis is made mainly by two-dimensional ultrasonography (2DUS) with color Doppler, which shows a large vessel in the center of the mass. The three-dimensional power Doppler ultrasound (3D power Doppler) and dynamic contrast-enhanced magnetic resonance imaging (MRI) are new diagnostic modalities not yet published in literature. We report a case of metastatic choriocarcinoma with left ovary involvement in a 48-year-old woman with history of molar pregnancy and irregular follow-up of this disease. We emphasize the main findings by 2DUS with color Doppler, 3D power Doppler and dynamic contrast-enhanced MRI. 3D power Doppler is able to improve the assessment of anatomical relationships of vessels with the ovarian mass, while the resonance angiography allows us to evaluate the anatomic relations of the mass and adjacent structures, as well as the iliac vessels. The 3D power Doppler and dynamic contrast-enhanced MRI are promising methods in the evaluation of metastasis arising from gestational trophoblastic tumors.

Handheld Force Controlled Ultrasound Probe

An actuated handheld force-feedback controlled ultrasound probe has been developed. The controller maintains a prescribed contact force between the probe and a patient’s body. The device will enhance the diagnostic capability of free-hand elastography, swept-force compound imaging and make it easier for a technician to acquire repeatable (i.e., directly comparable) images over time. The mechanical system consists of an ultrasound probe, a ball-screw-driven linear actuator, and a force/torque sensor. The feedback controller commands the motor to rotate the ball screw to translate the ultrasound probe in order to maintain a desired contact force. In preliminary user studies, it was found that the control system maintained a constant contact force with 1.7 times less variation than human subjects provided with a visual force display. Users without a visual force display were only able to maintain a constant force with 20 times worse variation than the automatic controller. The system was also used to determine the viscoelastic properties of soft tissues.

Elastic deformation behaviour of Ti-24Nb-4Zr-7.9Sn for biomedical applications

In this paper, the elastic deformation behaviour of a recently developed beta-type titanium alloy Ti-24Nb-4Zr-7.9Sn (wt.%) that consists of non-toxic elements and is intended for biomedical applications is described. Tensile tests show that this alloy in the as hot-rolled state exhibits peculiar non-linear elastic behaviour with maximum recoverable strain up to 3.3% and incipient Young's modulus of 42GPa. Solution treatment at high temperature has trivial effect on super-elasticity but decreases strength and slightly increases the incipient Young's modulus. Ageing treatment in the (alpha+beta) two-phase field increases both strength and Young's modulus and results in a combination of high strength and relatively low elastic modulus. In spite of the formation of the alpha phase, short time ageing has no effect on super-elasticity, whereas the non-linear elastic behaviour transforms gradually to normal linear elasticity with the increase of ageing time. We suggest sluggish, partially reversible processes of stress-induced phase transformation and/or incipient kink bands as the origin of the above peculiar elastic behaviour.

Six cases of ectopic ACTH syndrome caused by thymic carcinoid

The ectopic ACTH syndrome (EAS) caused by thymic carcinoid is rare and its diagnosis remains a challenge to the endocrinologist. Here are six cases of EAS with a typical Cushing habitus accompanied by hyperpigmentation and hypokalemia. For all six patients, the high dose (8 mg) dexamethasone suppression test (HDDST) showed lack of suppression, computed tomography (CT) scanning documented anterior mediastinal masses, and the mediastenal tumors removed were confirmed as ACTH secreting thymic carcinoids by positive ACTH and NSE staining. Our data indicate that HDDST chest radiologic imaging and other laboratory examinations will greatly assist in diagnosing the thymic carcinoid-induced EAS at an earlier stage, which will significantly improve the long-term survival of the patient.

Chemoreflex function in heart failure

Peripheral and central chemoreflexes are the dominant autonomic mechanisms regulating ventilatory patterns in response to changes in partial pressures of oxygen and carbon dioxide in arterial blood and exert powerful effects on neural circulatory control. Both reflex pathways are capable of eliciting increases in sympathetic nerve traffic and consequent increases in blood pressure. Chronic heart failure is accompanied by a sustained elevation in sympathetic nerve traffic, which is thought to be an important component in the pathophysiology and progression of the disease. The role of chemoreflex mechanisms in the control of sympathetic function during heart failure is an important topic for which there are many questions and few answers. This review summarizes available evidence documenting peripheral and central chemoreflex function in heart failure, possible mechanisms for their alteration, and their possible contribution to ventilatory, and circulatory abnormalities that occur in heart failure.

Construction of a yeast one-hybrid system with the xylanase2 promoter from Trichoderma reesei to isolate transcriptional activators

AIMS

To construct a yeast one-hybrid system and isolate transcriptional activators.

METHODS AND RESULTS

A 1.1-kb promoter region of xylanase2 from Trichoderma reesei was cloned by PCR and sequenced (GenBank accession number: AY263380). Sequence analysis revealed that typical binding sites for several transcription factors in filamentous fungi, such as CREI, XLNR, ALCR, AREA and CCAAT enhancer, are located in the promoter. To isolate xyn2 transcription factors, the reporter plasmid of a yeast one-hybrid system was constructed on the backbone of the plasmid pRS415 containing the leu2 selective marker, with the xyn2 promoter region and Saccharomyces cerevisiae his4 as a reporter gene. The reporter gene contained 123-bp minimal promoter region. The S. cerevisiae H158 strain containing the reporter plasmid was transformed with a T. reesei expression cDNA library, and 34 transformants were collected from SC-Leu-His-Ura plates. The isolation of the gene ace2 from several transformants showed that the one-hybrid system approach was successful. Then, approx. 59 mg l(-1) of ace2 was overexpressed in Escherichia coli BL21.

SIGNIFICANCE AND IMPACT OF THE STUDY

The yeast one-hybrid system is suitable for isolating transcription factors of filamentous fungi. ACE II is a main and universal transcriptional activator that controls cellulase and hemicellulase transcription regulation in T. reesei.

Effects of N-(4-hydroxyphenyl)retinamide on hTERT expression in the bronchial epithelium of cigarette smokers

BACKGROUND

Telomerase activation plays a critical role in tumorigenesis. To determine the role of telomerase in early lung carcinogenesis and as a potential biomarker in chemoprevention trials, we analyzed the expression of the human telomerase reverse transcriptase catalytic subunit (hTERT) in bronchial biopsy specimens from cigarette smokers who were enrolled in a randomized, double-blinded, placebo-controlled chemoprevention trial of N-(4-hydroxyphenyl)retinamide (4-HPR).

METHODS

We obtained biopsy specimens from six predetermined sites in the bronchial tree from the 57 participants, before treatment and 6 months after treatment with 4-HPR or placebo. We used in situ hybridization to examine hTERT messenger RNA (mRNA) expression in 266 pretreatment (baseline) and post-treatment site-paired biopsy specimens from 27 patients in the 4-HPR-treated group and from 30 patients in the placebo-treated group. All statistical tests were two-sided.

RESULTS

At baseline, 62.4% (95% confidence interval [CI] = 53.9% to 71%) of the biopsy specimens obtained from the group treated with 4-HPR and 65.2% (95% CI = 57.4% to 73.1%) of the biopsy specimens obtained from the placebo-treated group expressed hTERT mRNA. After 6 months, 45.6% (95% CI = 36.9% to 54.3%) of the biopsy specimens obtained from the 4-HPR-treated group and 68.1% (95% CI = 60.4% to 75.8%) of the biopsy specimens obtained from the placebo-treated group expressed hTERT mRNA. The reduction in hTERT expression observed between the two treatment groups over time was statistically significant (P =.01) when we used the biopsy site as the unit of analysis, but not when we used the individual as the unit of analysis (P =.37).

CONCLUSIONS

Telomerase is frequently reactivated in the lungs of cigarette smokers. The modulation of hTERT expression in 4-HPR-treated smokers suggests that a novel molecular mechanism underlies the potential chemopreventive properties of 4-HPR. hTERT expression is a promising potential biomarker for risk assessment and for the evaluation of the efficacy of chemopreventive agents in lung carcinogenesis.

All-trans-retinoic acid enhances the effect of adenovirus-mediated wild-type p53 gene transfer in head and neck squamous cell carcinoma

OBJECTIVES

Adenovirus-mediated p53 (AdCMVp53) gene therapy for cancer is currently undergoing phase III clinical trials. One problematic aspect of this therapy is that the current protocols result in low transduction of the therapeutic virus in vivo. To search new modalities that can enhance the effect of AdCMVp53 gene therapy, we focused on retinoids.

METHODS

To study the effect of ATRA in combination with AdCMVp53 gene therapy, we pretreated head and neck squamous cell carcinoma (HNSCC) cells for 72 hours with a low-dose All-trans-retinoic acid (ATRA) (10-7 M-10-8 M) which will not affect the in vitro cell growth, and then infected the cells with low MOI (30MOI) AdCMVp53. In vitro cell proliferation assays, cell cycle assays were performed. Expression of p53 and p53-related gene products, BAX and p21, were examined.

RESULTS

The combined treatment with ATRA and Ad-p53 suppressed cell growth and induced apoptosis significantly more than AdCMVp53 treatment alone (P <.05). p53 expression significantly increased more after the combined treatment than after either treatment alone, at both the transcription and protein levels. In addition, increased expression of p21 and BAX, which are downstream gene products of p53, was observed in the combination. ATRA also enhanced the expression of green fluorescent protein (GFP) transduced by an adenovirus-cytomegalovirus (CMV)-GFP vector suggesting ATRA enhances adenovirus-CMV-promoted vectors through transcription.

CONCLUSIONS

Our results indicate that ATRA enhances AdCMVp53 expression through transcriptional mechanisms and can synergistically induce apoptosis in HNSCC cells. ATRA has a potential to enhance the effect of adenovirus-mediated p53 gene therapy for HNSCC.

Helping processes in a mutual aid organization for persons with emotional disturbance

To date, the notion of helpfulness of group processes has been equivocal in research on self-help groups. This article argues that findings drawn from the participants' subjective appraisals of helpfulness carry meanings different from those drawn from the correlational approach. In a mutual aid organization serving adults with mental health problems, the study found that, whereas universality, self-disclosure, and instillation of hope were the most valued processes, support and catharsis were the strongest correlates of benefits of participation. The authors propose a two-level hierarchy that distinguishes sustaining and beneficial factors. Different sets of factors should constitute the focus of facilitation at different stages of group development.

Activation of cardiac afferents by arachidonic acid: relative contributions of metabolic pathways

Arachidonic acid (AA) is metabolized via cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P-450 (CP450) pathways to a variety of bioactive products. The sensitivity of cardiac afferent endings to AA and its metabolites, especially those derived from LOX and CP450 pathways, is currently unclear. We examined AA-induced activation of cardiac vagal chemosensitive afferents in non- and postischemic hearts in rats and evaluated the relative contributions of the three metabolic pathways to the effects. Epicardial application of AA activated the cardiac afferents dose dependently in both nonischemic and postischemic hearts, with afferent responses greater in the latter condition. In nonischemic hearts, the afferent response to AA was abolished only after simultaneous administration of indomethacin and 17-octadecynoic acid (COX and CP450 inhibitors, respectively). Nordihydroguaiaretic acid (a LOX inhibitor) had no effect on the afferent response to AA. In postischemic hearts, abolition of the afferent response to AA required simultaneous blockade of all three pathways. None of the AA metabolic inhibitors affected resting activity of cardiac afferents in nonischemic hearts, but each suppressed afferent activity during ischemia-reperfusion. Most COX metabolites, CP450 metabolites, and 5-LOX metabolites tested were capable of activating cardiac afferents. The 12-LOX metabolites and 15-LOX metabolites had no effect on afferent activity. These data indicate that in the nonischemic heart, basal AA metabolism does not contribute to resting afferent activity, but AA is capable of activating cardiac afferents via COX and CP450 but not LOX pathways. During ischemia-reperfusion, all three metabolic pathways contribute to activation of cardiac vagal afferents with an enhanced responsiveness to AA. Our results suggest that induction of the 5-LOX pathway contributes to the enhanced sensitivity of cardiac vagal afferents to AA in the ischemic condition.

Evidence that the death receptor DR4 is a DNA damage-inducible, p53-regulated gene

DR4 (TRAIL-R1), a member of the tumor necrosis factor receptor superfamily, is a cell surface receptor that triggers the apoptotic machinery upon binding to its ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Although three other TRAIL receptors DR5, DcR1, and DcR2 are induced by DNA damage and are regulated by the wild-type p53 tumor suppressor, it was not known whether these factors also affect DR4 expression. In this study, we found that DR4 expression is also enhanced by DNA damage whether induced by ionizing radiation or by chemotherapeutic agents. The induction was observed predominantly in cells containing wild-type p53 and was similar to the regulation patterns of DR5 and Fas, two other members of the family which are known to be regulated by p53. Transfection of HPV 16 E6 gene into cells with wild-type p53, which decreased the level of p53 protein, resulted in suppression of DR4 induction by DNA-damaging agents. Conversely, introduction of exogenous wild-type p53 through adenovirus infection has led to upregulation of endogenous DR4 in cells with mutant p53. Moreover, the transcription inhibitor actinomycin D abolished DNA-damaging agent-induced DR4 expression. Thus, DR4 appears to be a DNA damage-inducible, p53-regulated gene.

Identification of retinamides that are more potent than N-(4-hydroxyphenyl)retinamide in inhibiting growth and inducing apoptosis of human head and neck and lung cancer cells

The synthetic retinoid, N-(4-hydroxyphenyl)retinamide (4HPR), which is currently being evaluated in clinical trials for cancer prevention and therapy, inhibits the growth of a variety of malignant cells through induction of apoptosis. However, in the majority of tumor cells, this inhibitory effect of 4HPR requires high concentrations (>1 microM), which exceed the peak plasma level measured in humans. In the present study, we compared and contrasted the effects of several synthetic retinamides on the growth of human lung and head and neck cancer cells in vitro. We found that some retinamides, especially N-(2-carboxyphenyl)retinamide (2CPR), exhibited better growth inhibitory effects than 4HPR in some of the cell lines. 2CPR exerted potent growth inhibitory effects in 5 of 10 head and neck cancer cell lines and in 1 of 10 lung cancer cell lines (IC(50), <0.8 microM). 2CPR (1 microM) induced apoptosis ranging from 10 to 60% in four of five cell lines, whereas 4HPR was ineffective at the same concentration. Unlike 4HPR, 2CPR (up to 10 microM) failed to induce reactive oxygen species production in these sensitive cell lines but could activate caspases 3 and 7 as well as increase poly(ADP-ribose)polymerase cleavage. Interestingly, the effect of 2CPR on cell growth could be suppressed by the specific retinoic acid receptor pan antagonist AGN193109. Our results suggest that 2CPR acts via retinoic acid receptors and may be a good candidate for prevention and treatment of some head and neck and lung cancers.

Apoptosis induction by chemopreventive agents

The goals of cancer chemoprevention are to inhibit the induction or suppress the progression of preneoplastic lesions to invasive cancer by using specific natural or synthetic chemical agents. Numerous studies have demonstrated that suppression of apoptosis or defects in apoptotic pathways contribute to expansion of initiated or aberrant clones leading to cancer development. Therefore, agents that can eliminate aberrant clones by induction of apoptosis rather than merely slowing down their proliferation may have chemopreventive potential. The increased understanding of apoptosis pathways has directed attention to components of these pathways as potential targets for not only chemotherapeutic but also chemopreventive agents. Indeed, an increasing number of previously identified chemopreventive agents including retinoids, vitamin D(3) analogues, triterpenoids, butyroids, monoterpenoids, nonsteroidal antiinflammatory agents and others were found recently to enhance apoptosis in a variety of premalignant or malignant cell types in vitro and in a few animal models in vivo and in clinical trials. Further understanding of the effects of potential chemopreventive agents on specific components of the pathways that lead to apoptosis may provide a rational approach to use such agents alone or in combination with other agents to enhance apoptosis as a strategy for effective chemoprevention of cancer.

Overexpression of BCL2 blocks TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human lung cancer cells

The tumor necrosis factor (TNF) related apoptosis-inducing ligand (TRAIL or Apo2L) and its receptors are members of the tumor necrosis factor superfamily. TRAIL triggers apoptosis by binding to its two proapoptotic receptors DR4 and DR5, a process which is negatively regulated by binding of TRAIL to its two decoy receptors TRID and TRUNDD. Here, we show that TRAIL effectively induces apoptosis in H460 human non-small-cell lung carcinoma cells via cleavage of caspases 8, 9, 7, 3, and BID, release of cytochrome c from the mitochondria, and cleavage of poly (ADP-ribose) polymerase (PARP). However, overexpression of Bcl2 blocked TRAIL-induced apoptosis in H460 cells, which correlated with the Bcl2 protein levels. Importantly, the release of cytochrome c and cleavage of caspase 7 triggered by TRAIL were considerably blocked in Bcl2 overexpressing cells as compared to vector control cells. Moreover, inhibition of TRAIL-mediated cytochrome c release and caspase 7 activation by Bcl2 correlated with the inability of PARP to be cleaved and the inability of the Bcl2 transfectants to undergo apoptosis. Thus, these results suggest that Bcl2 can serve an anti-apoptotic function during TRAIL-dependent apoptosis by inhibiting the release of cytochrome c and activation of caspase 7, thereby blocking caspase 7-dependent cleavage of cellular substrates.

Augmentation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis by the synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) through up-regulation of TRAIL receptors in human lung cancer cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis via the death receptors DR4 and DR5 in different transformed cells in vitro and exhibits potent antitumor activity in vivo with minor side effects. The synthetic retinoid CD437 is a potent inducer of apoptosis in cancer cells through increased levels of death receptors. We demonstrate that treatment of human lung cancer cells with a combination of suboptimal concentrations of CD437 and TRAIL enhanced induction of apoptosis in tumor cell lines with wild-type p53 but not in normal lung epithelial cells. CD437 up-regulated DR4 and DR5 expression. The CD437 and TRAIL combination enhanced activation of caspase-3, caspase-7, caspase-8, and caspase-9 and the subsequent cleavage of poly(ADP-ribose) polymerase and DNA fragmentation factor 45. Caspase inhibitors blocked the induction of apoptosis by this combination. Moreover, this combination induced Bid cleavage and increased cytochrome c release from mitochondria. These results suggest that the mechanism of enhanced apoptosis by this combination involves p53-dependent increase of death receptors by CD437, activation of these receptors by TRAIL, enhanced Bid cleavage, release of cytochrome c, and activation of caspase-3, caspase-7, caspase-8, and caspase-9. These findings suggest a novel strategy for the prevention and treatment of human lung cancer with the CD437 and TRAIL combination.

Induction of Fas expression and augmentation of Fas/Fas ligand-mediated apoptosis by the synthetic retinoid CD437 in human lung cancer cells

The synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) induces apoptosis in a variety of cancer cells. Recently, we demonstrated that CD437 induces apoptosis in human non-small cell lung cancer (NSCLC) cells expressing wild-type p53 by increasing the level of the death domain-containing cell surface receptor Killer/DR5. In the present study, we investigated whether CD437 induced the expression of Fas (CD95/APO-1), a cell surface protein belonging to the tumor necrosis factor receptor superfamily, which induces apoptosis upon interaction with Fas ligand (FasL) or agonistic antibodies. We found that CD437 increased the level of Fas mRNA in a time- and concentration-dependent manner in NSCLC H460 cells. The increased Fas expression was also identified at the protein level. CD437 induced Fas expression in three NSCLC cell lines with wild-type p53 but not in six NSCLC cell lines containing mutant p53. Moreover, enhanced degradation of wild-type p53 protein in NSCLC cells expressing human papillomavirus-16 E6 oncoprotein blocked CD437-induced Fas expression. These results implicate the involvement of wild-type p53 in CD437-induced Fas expression in human NSCLC cells. CD437 did not change Fas mRNA stability, and actinomycin D abolished CD437-induced expression of Fas mRNA, suggesting that CD437 induces Fas expression at the transcriptional level. The combination of CD437 and FasL or CD437 and agonistic anti-Fas antibody caused synergistic induction of apoptosis. Furthermore, CD437 augmented Fas/ FasL-induced apoptosis in cell lines with wild-type p53 but not in cell lines having mutant p53, indicating that a p53-dependent mechanism is also involved in this effect. Taken together, these results demonstrate that increased Fas expression may play an important role in CD437-induced, p53-dependent apoptosis in human NSCLC cells.

Oxidative stress impairs cardiac chemoreflexes in diabetic rats

We investigated the effects of diabetes mellitus and antioxidant treatment on the sensory and reflex function of cardiac chemosensory nerves in rats. Diabetes was induced by streptozotocin (STZ; 85 mg/kg ip). Subgroups of sham- and STZ-treated rats were chronically treated with an antioxidant, vitamin E (60 mg/kg per os daily, started 2 days before STZ). Animals were studied 6-8 wk after STZ injection. We measured renal sympathetic nerve activity (RSNA), mean arterial blood pressure (MABP), and cardiac vagal and sympathetic afferent activities in response to stimulation of chemosensitive sensory nerves in the heart by epicardial application of capsaicin (Caps) and bradykinin (BK). In cardiac sympathetic-denervated rats, Caps and BK (1-10.0 microg) evoked a vagal afferent mediated reflex depression of RSNA and MABP, which was significantly blunted in STZ-treated rats (P < 0.05). In vagal-denervated rats, Caps and BK (1-10.0 microg) evoked a sympathetic afferent-mediated reflex elevation of RSNA and MABP, which also was significantly blunted in STZ-treated rats (P < 0.05). Chronic vitamin E treatment effectively prevented these cardiac chemoreflex defects in STZ-treated rats without altering resting blood glucose or hemodynamics. STZ-treated rats with insulin replacement did not exhibit impaired cardiac chemoreflexes. In afferent studies, Caps and BK (0.1 g-10.0 microg) increased cardiac vagal and sympathetic afferent nerve activity in a dose-dependent manner in sham-treated rats. These responses were significantly blunted in STZ-treated rats. Vitamin E prevented the impairment of afferent discharge to chemical stimulation in STZ rats. The following were concluded: STZ-induced, insulin-dependent diabetes in rats extensively impairs the sensory and reflex properties of cardiac chemosensitive nerve endings, and these disturbances can be prevented by chronic treatment with vitamin E. These results suggest that oxidative stress plays an important role in the neuropathy of this autonomic reflex in diabetes.

Implication of multiple mechanisms in apoptosis induced by the synthetic retinoid CD437 in human prostate carcinoma cells

The synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) induces apoptosis in several types of cancer cell. CD437 inhibited the growth of both androgen-dependent and -independent human prostate carcinoma (HPC) cells in a concentration-dependent manner by rapid induction of apoptosis. CD437 was more effective in killing androgen-independent HPC cells such as DU145 and PC-3 than the androgen-dependent LNCaP cells. The caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK blocked apoptosis induced by CD437 in DU145 and LNCaP cells, in which increased caspase-3 activity and PARP cleavage were observed, but not in PC-3 cells, in which CD437 did not induce caspase-3 activation and PARP cleavage. Thus, CD437 can induce either caspase-dependent or caspase-independent apoptosis in HPC cells. CD437 increased the expression of c-Myc, c-Jun, c-Fos, and death receptors DR4, DR5 and Fas. CD437's potency in apoptosis induction in the different cell lines was correlated with its effects on the expression of oncogenes and death receptors, thus implicating these genes in CD437-induced apoptosis in HPC cells. However, the importance and contribution of each of these genes in different HPC cell lines may vary. Because CD437 induced the expression of DR4, DR5 and Fas, we examined the effects of combining CD437 and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and Fas ligand, respectively, in HPC cells. We found synergistic induction of apoptosis, highlighting the importance of the modulation of these death receptors in CD437-induced apoptosis in HPC cells. This result also suggests a potential strategy of using CD437 with TRAIL for treatment of HPC. Oncogene (2000) 19, 4513 - 4522.