Local NF-κB Activation Promotes Parathyroid Hormone Synthesis and Secretion in Uremic Patients

Secondary hyperparathyroidism (SHPT) in uremic patients is characterized by parathyroid gland (PTG) hyperplasia and parathyroid hormone (PTH) elevation. Previously, we demonstrated that NF-κB activation contributed to parathyroid cell proliferation in rats with chronic kidney disease. Although vitamin D inhibits inflammation and ameliorates SHPT, the contribution of vitamin D deficiency to SHPT via local NF-κB activation remains to be clarified. PTGs collected from 10 uremic patients with advanced SHPT were used to test the expressions of vitamin D receptor (VDR), NF-κB, and proliferating cell nuclear antigen (PCNA). Freshly excised PTG tissues were incubated for 24 hours in vitro with VDR activator (VDRA) calcitriol or NF-κB inhibitor pyrrolidine thiocarbamate (PDTC). Chromatin immunoprecipitation (ChIP) and luciferase reporter assays were performed to investigate the regulation of PTH transcription by NF-κB. We found higher levels of activated NF-κB and lower expression of VDR in nodular hyperplastic PTGs than in diffuse hyperplasia. In cultured PTG tissues, treatment with VDRA or PDTC inhibited NF-κB activation and PCNA expression, and downregulated preproPTH mRNA and intact PTH levels. ChIP assays demonstrated the presence of NF-κB binding sites in PTH promoter. Furthermore, in luciferase reporter assays, addition of exogenous p65 significantly increased PTH luciferase activity by 2.4-fold (P < 0.01), while mutation of NF-κB binding site at position -908 of the PTH promoter suppressed p65-induced PTH reporter activity (P < 0.01). In summary, local NF-κB activation contributes to SHPT and mediates the transcriptional activation of PTH directly in uremic patients. Vitamin D deficiency may be involved in SHPT via the activation of NF-κB pathway.

Excessive Activation of TLR4/NF-κB Interactively Suppresses the Canonical Wnt/β-catenin Pathway and Induces SANFH in SD Rats

Nuclear factor-kappa B (NF-κB) interactively affects the Wnt/β-catenin pathway and is closely related to different diseases. However, such crosstalk effect in steroid-associated necrosis of femoral head (SANFH) has not been fully explored and evaluated. In this study, early-stage SANFH was induced by two doses of lipopolysaccharide (LPS, 2 mg/kg/day) and three doses of methylprednisolone (MPS, 40 mg/kg/day). LPS and pyrrolidine dithiocarbamate (PDTC) were administered to activate the TLR4/NF-κB pathway and selectively block the activation of NF-κB, respectively. Results showed that PDTC treatment significantly reduced NF-κB expression, diminished inflammation, and effectively decreased bone resorption processes (osteoclastogenesis, adipogenesis, and apoptosis), which were evidently reinforced after osteonecrosis induction. Moreover, PDTC remarkably increased the interfered Wnt/β-catenin pathway and elevated bone formation processes (osteogenesis and angiogenesis). Ultimately, PDTC treatment effectively reduced the incidence of SANFH. Therefore, the excessive activation of TLR4/NF-κB may interactively suppress the Wnt/β-catenin pathway and induce SANFH. Hence, we propose NF-κB-targeted treatment as a novel therapeutic strategy for SANFH.

Analysis on curative effects and safety of 2% liranaftate ointment in treating tinea pedis and tinea corporis & cruris

The paper is intended to analyze and evaluate the specific curative effect and safety of 2% liranaftate ointment in treating patients with tinea pedis and tinea cruris. 1,100 cases of patients with tinea pedis and tinea corporis & cruris were selected as research objects and were divided into two groups according to the random number table method. They were treated with different methods: 550 cases of patients were treated with 2% liranaftate ointment for external use in the observation group and the rest 550 cases of patients were treated with 1% bifonazole cream in the control group. The treatment time was two weeks for patients with tinea corporis & cruris and four weeks for those with tinea pedis respectively. Meanwhile, the one-month follow-up visit was conducted among the patients to compare the curative effects of two groups. After the medication, the curative effectiveness rate was 87.65% (482/550) in the observation group, while that was 84.91% (467/550) in the control group. After the average follow-up visits of (15.5±2.4), the curative effectiveness rate 96.55% (531/550) in the observation group, while that was 91.45% (503/550) in the control group. Two groups of patients recovered well with a low incidence of adverse reactions in the treatment, and the overall curative effect was good with the inter-group difference at P>0.05, so it was without statistical significance. The curative effect of 2% liranaftate ointment is safe and obvious in treating tinea pedis and tinea corporis & cruris, so it is valuable for clinical popularization and application.

Pyrrolidine dithiocarbamate administered during ex-vivo lung perfusion promotes rehabilitation of injured donor rat lungs obtained after prolonged warm ischemia

Damaged lung grafts obtained after circulatory death (DCD lungs) and warm ischemia may be at high risk of reperfusion injury after transplantation. Such lungs could be pharmacologically reconditioned using ex-vivo lung perfusion (EVLP). Since acute inflammation related to the activation of nuclear factor kappaB (NF-κB) is instrumental in lung reperfusion injury, we hypothesized that DCD lungs might be treated during EVLP by pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB. Rat lungs exposed to 1h warm ischemia and 2 h cold ischemia were subjected to EVLP during 4h, in absence (CTRL group, N = 6) or in presence of PDTC (2.5g/L, PDTC group, N = 6). Static pulmonary compliance (SPC), peak airway pressure (PAWP), pulmonary vascular resistance (PVR), and oxygenation capacity were determined during EVLP. After EVLP, we measured the weight gain of the heart-lung block (edema), and the concentration of LDH (cell damage), proteins (permeability edema) and of the cytokines IL-6, TNF-α and CINC-1 in bronchoalveolar lavage (BAL), and we evaluated NF-κB activation by the degree of phosphorylation and degradation of its inhibitor IκBα in lung tissue. In CTRL, we found significant NF-κB activation, lung edema, and a massive release of LDH, proteins and cytokines. SPC significantly decreased, PAWP and PVR increased, while oxygenation tended to decrease. Treatment with PDTC during EVLP inhibited NF-κB activation, did not influence LDH release, but markedly reduced lung edema and protein concentration in BAL, suppressed TNFα and IL-6 release, and abrogated the changes in SPC, PAWP and PVR, with unchanged oxygenation. In conclusion, suppression of innate immune activation during EVLP using the NF-κB inhibitor PDTC promotes significant improvement of damaged rat DCD lungs. Future studies will determine if such rehabilitated lungs are suitable for in vivo transplantation.

Hydrogen sulfide attenuates gastric mucosal injury induced by restraint water-immersion stress via activation of KATP channel and NF-κB dependent pathway

AIM

To explore the effect of hydrogen sulfide (H₂S) on restraint water-immersion stress (RWIS)-induced gastric lesions in rats and the influence of adenosine triphosphate (ATP)-sensitive potassium (K_ATP) channels and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway on such an effect.

METHODS

Male Wistar rats were randomly divided into a control group, a physiological saline (PS) group, a sodium hydrosulfide (NaHS) group, a glibenclamide (Gl) group, Gl plus NaHS group, a pyrrolidine dithiocarbamate (PDTC) group, and a PDTC plus NaHS group. Gastric mucosal injury was induced by RWIS for 3 h in rats, and gastric mucosal damage was analyzed after that. The PS, NaHS (100 μmol/kg body weight), Gl (100 μmol/kg body weight), Gl (100 μmol/kg or 150 μmol/kg body weight) plus NaHS (100 μmol/kg body weight), PDTC (100 μmol/kg body weight), and PDTC (100 μmol/kg body weight) plus NaHS (100 μmol/kg body weight) were respectively injected intravenously before RWIS.

RESULTS

RWIS induced serious gastric lesions in the rats in the PS pretreatment group. The pretreatment of NaHS (a H₂S donor) significantly reduced the damage induced by RWIS. The gastric protective effect of the NaHS during RWIS was attenuated by PDTC, an NF-κB inhibitor, and also by glibenclamide, an ATP-sensitive potassium channel blocker, in a dose-dependent manner.

CONCLUSION

These results suggest that exogenous H₂S plays a protective role against RWIS injury in rats, possibly through modulation of K_ATP channel opening and the NF-κB dependent pathway.

Partial Enteral Nutrition Mitigated Ischemia/Reperfusion-Induced Damage of Rat Small Intestinal Barrier

Background and Aims: This study was designed to investigate a relatively optimum dose of partial enteral nutrition (PEN) which effectively attenuates intestinal barrier dysfunction initiated by ischemia/reperfusion injury (IRI). Methods: In experiment 1, 60 male Sprague-Dawley (SD) rats were subjected to intestinal IRI and assigned to six groups according to the different proportion of EN administrations: namely total parenteral nutrition (TPN or 0%EN), 10%EN, 20%EN, 40%EN, 60%EN, and total enteral nutrition (TEN or 100%) groups, the deficits of intraluminal calorie were supplemented by PN. In experiment 2, 50 male SD rats were subjected to intestinal IRI and divided into five groups based on the results of experiment 1: TPN, TEN, 20%EN, TPN plus pretreatment with NF-κB antagonist 30 min before IRI (TPN+PDTC), and TPN plus pretreatment with HIF-1α antagonist 30 min before IRI (TPN+YC-1) groups. Results: In experiment 1, previous IRI combined with subsequent EN shortage disrupted the structure of intestinal epithelial cell and tight junctions (TJs). While 20% dose of EN had an obviously protective effect on these detrimental consequences. In experiment 2, compared with TPN only, 20%EN exerted a significant protection of barrier function of intestinal epithelium. Analogous results were observed when TPN combined with specific NF-κB/HIF-1α inhibitors (PDTC and YC-1). Meanwhile, the expression of NF-κB/HIF-1α had a similar trend among the groups. Conclusions: Our findings indicate that 20%EN is the minimally effective dosage of EN which promotes the recovery of intestinal barrier function after IRI in a rat model. Furthermore, we discreetly speculate that this benefit is, at least partly, related to NF-κB/HIF-1α pathway expression.

Pyrrolidine dithiocarbamate inhibits superoxide anion-induced pain and inflammation in the paw skin and spinal cord by targeting NF-κB and oxidative stress

We evaluated the effect of pyrrolidine dithiocarbamate (PDTC) in superoxide anion-induced inflammatory pain. Male Swiss mice were treated with PDTC and stimulated with an intraplantar or intraperitoneal injection of potassium superoxide, a superoxide anion donor. Subcutaneous PDTC treatment attenuated mechanical hyperalgesia, thermal hyperalgesia, paw oedema and leukocyte recruitment (neutrophils and macrophages). Intraplantar injection of superoxide anion activated NF-κB and increased cytokine production (IL-1β, TNF-α and IL-10) and oxidative stress (nitrite and lipid peroxidation levels) at the primary inflammatory foci and in the spinal cord (L4-L6). PDTC treatment inhibited superoxide anion-induced NF-κB activation, cytokine production and oxidative stress in the paw and spinal cord. Furthermore, intrathecal administration of PDTC successfully inhibited superoxide anion-induced mechanical hyperalgesia, thermal hyperalgesia and inflammatory response in peripheral foci (paw). These results suggest that peripheral stimulus with superoxide anion activates the local and spinal cord oxidative- and NF-κB-dependent inflammatory nociceptive mechanisms. PDTC targets these events, therefore, inhibiting superoxide anion-induced inflammatory pain in mice.

Pyrrolidine Dithiocarbamate Inhibits NF-KappaB Activation and Upregulates the Expression of Gpx1, Gpx4, Occludin, and ZO-1 in DSS-Induced Colitis

Inflammatory bowel disease (IBD) correlates with oxidative stress, inflammation, and alteration in several signal pathways, including nuclear transcription factor-kappaB (NF-κB). Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, has been widely demonstrated to exhibit an antioxidant and anti-inflammatory function. This study aimed to test the hypothesis that NF-κB inhibitor PDTC confers a beneficial role in a colitis model induced by dextran sodium sulfate (DSS) in mouse. The results showed that DSS decreased daily weight gain, induced colonic inflammation, suppressed the expression of antioxidant enzymes and tight junctions, and activated NF-κB and nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathways. PDTC significantly upregulated (P < 0.05) Gpx1, Gpx4, occludin, and ZO-1 expressions in the DSS-induced colitis model. Meanwhile, PDTC reversed (P < 0.05) the activation of NF-κB signal pathway caused by DSS treatment. In conclusion, PDTC could serve as an adjuvant therapy for the patient with IBD.

Determination of methyl isocyanate in outdoor residential air near metam-sodium soil fumigations

The soil fumigant metam-sodium (CH3NHCS2Na) produces the bioactive respiratory irritant methyl isothiocyanate (MITC). Recent laboratory gas-phase oxidative studies indicate that MITC rapidly transforms to the more toxic methyl isocyanate (MIC) in the lower atmosphere. Inhalation exposure risks from MITC plus MIC may therefore be an occupational worker and/or bystander health concern. To address this concern, MIC was monitored, along with MITC, in outdoor residential air in Washington state during the peak fall metam fumigation season. XAD-7 cartridges, coated with 1-(2-pyridyl)piperazine, were developed to retain MIC as its stable substituted urea derivative. Of the 68 residential air measurements of MIC, 15 (22%) were observed to be above the California Environmental Protection Agency's chronic inhalation reference level of 1 μg/m(3), with an observed maximum MIC air concentration of 4.4 μg/m(3). This study indicates MIC air concentrations can be anticipated along with MITC in residential air where seasonal metam soil fumigant applications occur.

Maia PI, Sesti-Costa R, Lopes CD, Pereira TA, Milanezi CM, da Silva MAP, Lopez RFV, Silva JS, Deflon VM. In vitro and in vivo trypanocidal activity of H2bdtc-loaded solid lipid nanoparticles

The parasite Trypanosoma cruzi causes Chagas disease, which remains a serious public health concern and continues to victimize thousands of people, primarily in the poorest regions of Latin America. In the search for new therapeutic drugs against T. cruzi, here we have evaluated both the in vitro and the in vivo activity of 5-hydroxy-3-methyl-5-phenyl-pyrazoline-1-(S-benzyl dithiocarbazate) (H2bdtc) as a free compound or encapsulated into solid lipid nanoparticles (SLN); we compared the results with those achieved by using the currently employed drug, benznidazole. H2bdtc encapsulated into solid lipid nanoparticles (a) effectively reduced parasitemia in mice at concentrations 100 times lower than that normally employed for benznidazole (clinically applied at a concentration of 400 µmol kg(-1) day(-1)); (b) diminished inflammation and lesions of the liver and heart; and (c) resulted in 100% survival of mice infected with T. cruzi. Therefore, H2bdtc is a potent trypanocidal agent.

Evaluation of a dithiocarbamate derivative as a model of thiol oxidative stress in H9c2 rat cardiomyocytes

Thiol redox state (TRS) refers to the balance between reduced thiols and their corresponding disulfides and is mainly reflected by the ratio of reduced and oxidized glutathione (GSH/GSSG). A decrease in GSH/GSSG, which reflects a state of thiol oxidative stress, as well as thiol modifications such as S-glutathionylation, has been shown to have important implications in a variety of cardiovascular diseases. Therefore, research models for inducing thiol oxidative stress are important tools for studying the pathophysiology of these disease states as well as examining the impact of pharmacological interventions on thiol pathways. The purpose of this study was to evaluate the use of a dithiocarbamate derivative, 2-acetylamino-3-[4-(2-acetylamino-2-carboxyethylsulfanylthiocarbonylamino)phenylthiocarbamoylsulfanyl]propionic acid (2-AAPA), as a pharmacological model of thiol oxidative stress by examining the extent of thiol modifications induced in H9c2 rat cardiomyocytes and its impact on cellular functions. The extent of thiol oxidative stress produced by 2-AAPA was also compared to other models of oxidative stress including hydrogen peroxide (H2O2), diamide, buthionine sulfoximine, and N,N׳-bis(2-chloroethyl)-N-nitroso-urea. Results indicated that 2-AAPA effectively inhibited glutathione reductase and thioredoxin reductase activities and decreased the GSH/GSSG ratio by causing a significant accumulation of GSSG. 2-AAPA also increased the formation of protein disulfides as well as S-glutathionylation. The alteration in TRS led to a loss of mitochondrial membrane potential, release of cytochrome c, and increase in reactive oxygen species production. Compared to other models, 2-AAPA is more potent at creating a state of thiol oxidative stress with lower cytotoxicity, higher specificity, and more pharmacological relevance, and could be utilized as a research tool to study TRS-related normal and abnormal biochemical processes in cardiovascular diseases.

Gold(III)-dithiocarbamato peptidomimetics in the forefront of the targeted anticancer therapy: preclinical studies against human breast neoplasia

Since the serendipitous discovery of cisplatin, platinum-based drugs have become well-established antitumor agents, despite the fact that their clinical use is limited by many severe side-effects. In order to both improve the chemotherapeutic index and broaden the therapeutic spectrum of current drugs, our most recent anti-neoplastic agents, Au(III) complexes, were designed as carrier-mediated delivery systems exploiting peptide transporters, which are up-regulated in some cancers. Among all, we focused on two compounds and tested them on human MDA-MB-231 (resistant to cisplatin) breast cancer cell cultures and xenografts, discovering the proteasome as a major target both in vitro and in vivo. 53% inhibition of breast tumor growth in mice was observed after 27 days of treatment at 1.0 mg kg⁻¹ d⁻¹, compared to control. Remarkably, if only the most responsive mice are taken into account, 85% growth inhibition, with some animals showing tumor shrinkage, was observed after 13 days. These results led us to file an international patent, recognizing this class of gold(III) peptidomimetics as suitable candidates for entering phase I clinical trials.

Comparison of field methyl isothiocyanate flux following Pacific Northwest surface-applied and ground-incorporated fumigation practices

BACKGROUND

A fumigant volatilization emission was conducted in Washington State in the fall of 2008 to estimate flux following applications of metam sodium by modified low-boom-height (LBH) center-pivot chemigation and soil-incorporated shank injection. This study was performed in a commercial potato field circle to assess emission rates and total cumulative field loss of methyl isothiocyanate (MITC) (the biologically active conversion product of metam sodium) under conditions typical for fall Pacific Northwest potato preplant fumigation. This assessment provides regionally specific MITC emission rate information for modeling appropriate field-edge set-back buffer distances for bystander protection.

RESULTS

Soil-incorporated shank injection appreciably reduced MITC emissions, with lower periodic flux compared with low-drift surface-applied LBH chemigation during treatment applications and over the 4 day post-fumigation experimental timeframe. The estimated total cumulative fumigant loss was 13% by shank injection compared with 47% by LBH chemigation over the application/post-application monitoring period.

CONCLUSION

The greater adoption of shank-injection fumigation will immediately aid in reducing bystander inhalation exposure to MITC, especially in high-soil-fumigation regions existing at the rural-urban interface.

[Regulation of inflammatory pain by NF-κB and CX3CR1 at the spinal cord of rats]

OBJECTIVE

To observe the effect of intrathecal injection of nuclear factor-κB (NF-κB) inhibitor of pyrrolidine dithiocarbamate (PDTC) on pain sensitivity thresholds and the expression of spinal cord CX3C chemokine receptor 1 (CX3CR1) in monoarthritis (MA) model in rats.

METHODS

Forty-eight Sprague-Dawley rats were randomly divided into 4 groups (12 each) after successful intrathecal catheterization: (1) sham operation with physiological saline group (the sham group); (2) MA with normal saline group (the MA group); (3) 10 μL 100 μmol/L PDTC before MA (the PDTC pre-treatment group); (4)MA before 10 μL 100 μmol/L PDTC (the PDTC post-treatment group). Normal saline or PDTC was injected 5 d after the intrathecal catheterization. Pain sensitivity thresholds were measured in the 4 groups before and after the intrathecal injection at different time points. Rat monoarthritis model was subsequently built by injecting complete Freund's adjuvant (CFA) into the left ankle joint of the rats. On day 3 after the intrathecal injection, expression of microglia in the L₅ spinal cord segment was observed by immunohistochemical method, and the lumbar segments L₄-L₅ of spinal cord were taken to perform RT-PCR to examine the expression of NF-κB mRNA and CX3CR1 mRNA.

RESULTS

Compared with the MA group, the pain sensitivity thresholds in the sham group, the PDTC pre-treatment group and the PDTC post-treatment group at each time point after the intrathecal injection increased significantly (P<0.05), while microglia in the L₅ spinal cord segment decreased significantly (P<0.05) and expression of CX3CR1 mRNA and NF-κB mRNA in the lumbar segments L₄-L₅ of spinal cord decreased significantly (P<0.05).

CONCLUSION

The hyperalgesic effect of the CFA-induced model of monoarthritis can be relieved by intrathecal injection of NF-κB inhibitor PDTC. Its mechanism is possibly related to NF-κB signal pathway which is involved in the formation of inflammatory pain through regulating CX3CR1 expression.

Enhanced antitumor efficacy of folate-linked liposomal doxorubicin with TGF-β type I receptor inhibitor

Tumor cell targeting of drug carriers is a promising strategy and uses the attachment of various ligands to enhance the therapeutic potential of chemotherapy agents. Folic acid is a high-affinity ligand for folate receptor, which is a functional tumor-specific receptor. The transforming growth factor (TGF)-β type I receptor (TβR-I) inhibitor A-83-01 was expected to enhance the accumulation of nanocarriers in tumors by changing the microvascular environment. To enhance the therapeutic effect of folate-linked liposomal doxorubicin (F-SL), we co-administrated F-SL with A-83-01. Intraperitoneally injected A-83-01-induced alterations in the cancer-associated neovasculature were examined by magnetic resonance imaging (MRI) and histological analysis. The targeting efficacy of single intravenous injections of F-SL combined with A-83-01 was evaluated by measurement of the biodistribution and the antitumor effect in mice bearing murine lung carcinoma M109. A-83-01 temporarily changed the tumor vasculature around 3 h post injection. A-83-01 induced 1.7-fold higher drug accumulation of F-SL in the tumor than liposome alone at 24 h post injection. Moreover F-SL co-administrated with A-83-01 showed significantly greater antitumor activity than F-SL alone. This study shows that co-administration of TβR-I inhibitor will open a new strategy for the use of FR-targeting nanocarriers for cancer treatment.

Activation of hypoxia-inducible factor-1alpha via nuclear factor-kappa B in rats with chronic obstructive pulmonary disease

Accumulating data suggested that hypoxia inducible factor (HIF)-1alpha plays an important role in the evolution and propagation of the inflammatory process. To characterize the activation of HIF-1alpha in rats with chronic obstructive pulmonary disease (COPD) and examine the possible role of nuclear factor (NF)-kappaB in this process, rats were challenged by introtracheal instillation of lipopolysaccharide (LPS) and exposure to cigarette smoke. Pyrrolidine dithiocarbamate (PDTC) was administered via the oral route 1 h before LPS or cigarettes administration. Four weeks later, pulmonary function and histology were tested; bronchoalveolar lavage fluid (BALF) and arterial blood gases were assayed. Activation of pulmonary NF-kappaB was assessed by quantitative PCR, immunoblot analysis, and electrophoretic mobility shift assay, respectively. Results showed that LPS and smog induced the characteristics of COPD seen in human. PDTC alleviated the development of COPD and the levels of cytokines in BALF of PDTC+COPD group were significantly decreased compared with that of COPD group. The activation of pulmonary NF-kappaB was inhibited by PDTC and the accumulation of HIF-1alpha gene expression in the COPD group was attenuated by PDTC pretreatment. Furthermore, the mRNA levels of HIF-1alpha target genes heme oxygenase-1 (HO-1) and vascular endothelial growth factor (VEGF) were parallel to the attenuation of HIF-1alpha by PDTC. These findings indicated that the activation of HIF-1alpha pathway via NF-kappaB contributes to the development of COPD, and administration of NF-kappaB inhibitor may attenuate the development of COPD.

Differential effects of nitric oxide synthase inhibitors on anxiety in unstressed and stressed mice

Effects of selective nitric oxide synthase (NOS) inhibitors, 7-nitroindazole (7-NI), a selective inhibitor of neuronal nitric oxide synthase (nNOS) and aminoguanidine (AG), a selective inhibitor of inducible nitric oxide synthase (iNOS) on anxiety in unstressed and stressed mice were investigated using elevated plus maze (EPM) test and light-dark test (LDT). 7-NI (20 and 40 mg/kg, ip) produced anti-anxiety effect in unstressed mice but not in stressed mice. AG (50 and 100 mg/kg, ip) produced anxiolytic effect in stressed mice and failed to produce the similar effect in unstressed mice. Nitrite levels were increased in stressed mice, but not in unstressed mice, exposed to EPM and LDT for 5 min. Increased nitrite levels in stressed mice were attenuated by AG, but not by 7-NI. The effects of AG were enhanced by pyrrolidine-dithio-carbamate (PDTC), an inhibitor of NF-kappaB induction, in stressed mice. The results suggest the possible role of inducible nitric oxide synthase in stress-induced anxiogenesis as compared to unstressed mice, where neuronal form of NOS may plays predominant role.

[Suppression of experimental inflammation by anti-fungal agent liranaftate in mice]

To evaluate the anti-inflammatory activity of the thiocarbamate antifungal agent liranaftate, the edema and the neutrophil accumulation detected by the activity of neutrophil marker enzyme, myeloperoxidase (MPO), were examined following application of liranaftate to mouse ears with inflammation induced by phorbol 12-myristate 13-acetate (PMA). Topical 20 microl administration of liranaftate in a dose-range between 1-4% suppressed the increase in ear thickness 6 hr after PMA application dose-dependently. Similarly, it decreased the weight increase of an ear section after 24 hr dose-dependently. More than 1% of liranaftate also suppressed augmentation of MPO activity of the ear section. This and histological observation indicate that liranaftate treatment suppressed neutrophil accumulation in PMA-applied ear lesion. From these results, we discussed that liranaftate might suppress inflammatory symptoms caused by trychophytosis in a clinical condition.

NF-kappaB pathway inhibitors preferentially inhibit breast cancer stem-like cells

Accumulating evidence indicates that breast cancer is caused by cancer stem cells and cure of breast cancer requires eradication of breast cancer stem cells. Previous studies with leukemia stem cells have shown that NF-kappaB pathway is important for leukemia stem cell survival. In this study, by using MCF7 sphere cells as model of breast cancer stem-like cells, we evaluated the effect of NF-kappaB pathway specific inhibitors on human breast cancer MCF7 sphere cells. Three inhibitors including parthenolide (PTL), pyrrolidinedithiocarbamate (PDTC) and its analog diethyldithiocarbamate (DETC) were found to preferentially inhibit MCF7 sphere cell proliferation. These compounds also showed preferential inhibition in term of proliferation and colony formation on MCF7 side population (SP) cells, a small fraction of MCF7 cells known to enrich in breast cancer stem-like cells. The preferential inhibition effect of these compounds was due to inhibition of the NF-kappaB activity in both MCF7 sphere and MCF7 cells, with higher inhibition effect on MCF7 sphere cells than on MCF7 cells. PDTC was further evaluated in vivo and showed significant tumor growth inhibition alone but had better tumor growth inhibition in combination with paclitaxel in the mouse xenograft model than either PDTC or paclitaxel alone. This study suggests that breast cancer stem-like cells could be selectively inhibited by targeting signaling pathways important for breast cancer stem-like cells.

Combinations of N-Acetyl-S-(N-2-Phenethylthiocarbamoyl)-L-Cysteine and myo-inositol inhibit tobacco carcinogen-induced lung adenocarcinoma in mice

We have previously generated convincing evidence that combinations of N-acetyl-S-(N-2-phenethylthiocarbamoyl)-L-cysteine (PEITC-NAC; 3 micromol/g diet) and myo-inositol (MI; 56 micromol/g diet) were significantly more effective than the individual compounds as inhibitors of tobacco smoke carcinogen-induced lung tumorigenesis in A/J mice. In this study, we further investigated the efficacy of combinations of PEITC-NAC (9 or 15 micromol/g diet) and MI (56 micromol/g diet). Female A/J mice were treated with a mixture of the tobacco smoke carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene by gavage once weekly for 8 weeks. PEITC-NAC plus MI was given in the diet beginning at 1 day after the 4th of eight carcinogen treatments (temporal sequence A) or 1 week after the last carcinogen treatment (temporal sequence B). Regardless of the dose of carcinogen or PEITC-NAC plus MI, or temporal sequence, administration of PEITC-NAC plus MI significantly reduced the multiplicity of gross tumors and, in most instances, adenocarcinoma. PEITC-NAC plus MI was particularly effective against bigger tumors. The observed inhibition of lung tumorigenesis by PEITC-NAC plus MI was attributed, at least partly, to inhibition of cell proliferation and induction of apoptosis. These results clearly show the efficacy of PEITC-NAC plus MI in the prevention of tobacco carcinogen-induced lung adenocarcinoma in A/J mice and provide a basis for future evaluation of PEITC-NAC plus MI in clinical trials as a chemopreventive agent for current and former smokers.

Assessing the biological relevance of exposing freshwater organisms to atrazine and molinate in environmentally realistic exposure test systems

Assessing the toxicity of chemicals in treated laboratory water may not accurately represent the toxicity of chemicals in natural aquatic systems. In natural water, dissolved organic matter, suspended particulate matter, and sediment play key roles in the sorption of contaminants from the water. Our previously published series of papers illustrated that the presence of sediment in aquatic toxicity testing systems significantly (p < 0.05) reduced the bioavailability of the herbicides atrazine and molinate to five Australian freshwater organisms. It is not clear whether the reduced bioavailability means that the trigger values (TVs) in the current Australian and New Zealand water quality guidelines, which are calculated using toxicity data from water-only toxicity tests, provide appropriate environmental protection. Several new sets of TVs were derived in the present study and were compared to each other and to the current Australian and New Zealand TVs for atrazine and molinate. The current Australian and New Zealand TVs for atrazine and molinate provided appropriate protection to Australian freshwater species. Australian freshwater species have a sensitivity distribution similar to those of overseas species to atrazine and molinate.

Distribution and efficacy of drip-applied metam-sodium against the survival of Rhizoctonia solani and yellow nutsedge in plastic-mulched sandy soil beds

The effects of metam-sodium application rate on soil residence time, spatial and temporal distributions of methyl isothiocyanate and pest control efficacy were studied in a Georgia sandy soil. Metam-sodium 420 g L(-1) SL was drip applied at rates of 147 and 295 L ha(-1) in plastic-mulched raised beds. Methyl isothiocyanate concentrations in soil air space were monitored from four preselected sites: 10 and 20 cm below the emitter, and 20 and 30 cm laterally away from the emitter at 3, 12, 24, 48, 72, 120 and 240 h after chemigation. A higher rate of metam-sodium application resulted in higher methyl isothiocyanate concentrations in the soil. Highest methyl isothiocyanate concentrations were found at 20 cm below the emitter, and lowest at 30 cm laterally away from the emitter. Methyl isothiocyanate concentrations decreased with time and distance from the emitter. Lower methyl isothiocyanate concentration x time product values at 20 and 30 cm away from the emitter resulted in lower mortalities of Rhizoctonia solani Kühn and yellow nutsedge (Cyperus esculentus L.). The results demonstrated that methyl isothiocyanate can be delivered at lethal doses with drip-applied water downward within the beds. Lateral diffusion of methyl isothiocyanate from the point of application did not reach biologically active concentrations to affect the survival of R. solani or yellow nutsedge. Further studies on the lateral distribution of methyl isothiocyanate in sandy soils are needed to circumvent this limitation.

Evaluation of the effect of pyrrolidine dithiocarbamate in suppressing inflammation in mice with dextran sodium sulfate-induced colitis

AIM: To evaluate the effect of pyrrolidine dithio-carbamate (PDTC; an NF-κB inhibitor) administered at low (50 mg/kg) and high (100 mg/kg) doses in suppressing colitis in mice with dextran sodium sulfate (DSS)-induced colitis.

METHODS: Mice were divided into a DSS-untreated group (normal group), DSS-treated control group, DSS+PDTC-treated groupI(low-dose group), and DSS+PDTC-treated groupII (high-dose group). In each group, the disease activity index score (DAI score), intestinal length, histological score, and the levels of activated NF-κB and inflammatory cytokines (IL-1β and TNF-α) in tissue were measured.

RESULTS: The DSS+PDTC-treated groupII exhibited suppression of shortening of intestinal length and reduction of DAI score. Activated NF-κB level and IL-1β and TNF-α levels were significantly lower in DSS+PDTC-treated groupII.

CONCLUSION: These findings suggest that PDTC is useful for the treatment of ulcerative colitis.

A new type of orally active anti-diabetic Zn(II)-dithiocarbamate complex

In order to find orally active Zn(II) complexes that can treat diabetes mellitus (DM) at low doses, four new Zn(II)-dithiocarbamate complexes with Zn(II)-sulfur coordination bonds were prepared and their in vitro insulinomimetic activity and in vivo anti-diabetic ability were evaluated. Among the Zn(II)-dithiocarbamate complexes, the bis(pyrrolidine-N-dithiocarbamate)zinc(II) (Zn(pdc)(2)) complex was found to be the most effective in terms of inhibiting free fatty acid-release and enhancing glucose-uptake in adipocytes. After oral administration of the Zn(pdc)(2) complex to KK-A(y) mice with obesity and type 2 DM, we observed that the high blood glucose levels in the mice were lowered from approximately 500 mg/dL to 350 mg/dL within 6 days, and the effect was maintained during the administration period. Also, indicators of insulin resistance such as serum insulin, leptin, and triglyceride levels were also reduced compared with those in untreated mice. Moreover, the Zn(pdc)(2) complex improved not only the hypertension in the mice, but also the adiponectin level in the serum. On the basis of the results, the Zn(pdc)(2) complex is proposed to improve hyperglycemia and insulin resistance in type 2 DM animals on daily oral administrations.

P53 status influences regulation of HSPs and ribosomal proteins by PDTC and radiation

Pyrrolidine dithiocarbamate (PDTC) is a thiol-containing compound that can act under varying conditions as an anti-oxidant or pro-oxidant. Utilizing microarrays, we determined the effect of PDTC +/- ionizing radiation (IR) on the expression of heat shock protein (HSP) genes in isolated B6/129 wild-type (WT) and p53-/- spleen cells. Extremely significant microarrays demonstrated that PDTC, but not IR, markedly up-regulated the expression of the majority of detectable HSP genes in WT and many to a significantly greater degree in p53-/- deficient cells. Determination of the glutathione/glutathione disulfide ratio indicated that PDTC was acting as a pro-oxidant under these conditions. From these data we conclude that the clinical use of "antioxidants" with radiotherapy or chemotherapy must be very carefully based on knowledge of the p53 status of their intended normal and tumor target cells.