Sildenafil protective effects on high glucose-induced neurotoxicity in PC12 cells: the role of oxidative stress,apoptosis, and inflammation pathways in an in vitro cellular model for diabetic neuropathy

Objectives Diabetic neuropathy (DN) induces lifetime disability and there is currently no effective therapy to treat or to minimize patients suffering, so it is thereby imperative to develop therapeutic strategies for this disease. Since oxidative stress, mitochondrial dysfunction, apoptosis, and inflammation are crucial mechanisms in development and progression of DN, it is important to explore tools by which one can reduce factors related to these pathways. Herein, the understandings of the sildenafil neuroprotective effect through increase of cGMP level and the mediation of oxidative stress, apoptosis, and inflammation pathways on neurotoxicity induced by high glucose (HG) in PC12 cells as an in vitro cellular model for DN were investigated.

Methods We reported that the PC12 cells pre-treatment with sildenafil (0.008 μM) for 60 min and then exposing the cells to HG (25 mM for 72 h) or normal glucose (NG) (5 mM for 72 h) condition, show:

Results (1) significant attenuation in reactive oxygen species, MDA and TNF-a levels, Bax/Bcl-2 ratio, expression of caspase 3 and UCP2 proteins; (2) significant increase in viability, GSH/GSSG ratio, mitochondrial membrane potential, and ATP levels.

Conclusion All these data together led us to propose neuroprotective effect of sildenafil is probably through its antioxidant, antiapoptotic, and anti-inflammatory activities. Of course, further studies are required to explain the underlying mechanism of the sildenafil effects.     

Mapping the trajectory of the amygdalothalamic tract in the human brain

Although the thalamus is not considered primarily as a limbic structure, abundant evidence indicates the essential role of the thalamus as a modulator of limbic functions indirectly through the amygdala. The amygdala is a central component of the limbic system and serves an essential role in modulating the core processes including the memory, decision‐making, and emotional reactions. The amygdalothalamic pathway is the largest direct amygdalo‐diencephalic connection in the primates including the human brain. Given the crucial role of the amygdalothalamic tract (ATT) in memory function and diencephalic amnesia in stroke patients, diffusion tensor imaging may be helpful in better visualizing the surgical anatomy of this pathway noninvasively. To date, few diffusion‐weighted studies have focused on the amygdala, yet the fine neuronal connection of the amygdala and thalamus known as the ATT has yet to be elucidated. This study aimed to investigate the utility of high spatial resolution diffusion tensor tractography for mapping the trajectory of the ATT in the human brain. We studied 15 healthy right‐handed human subjects (12 men and 3 women with age range of 24–37 years old). Using a high‐resolution diffusion tensor tractography technique, for the first time, we were able to reconstruct and measure the trajectory of the ATT. We further revealed the close relationship of the ATT with the temporopontine tract and the fornix bilaterally in 15 healthy adult human brains.     

Enhanced expression of parathyroid hormone-related protein in prostate cancer as compared with benign prostatic hyperplasia

Parathyroid hormone-related protein (PTHrP) has been shown to be the primary factor responsible for humoral hypercalcemia of malignancy. Recently PTHrP has been shown to be an early-response gene that may be involved in cellular proliferation or differentiation. In addition, PTHrP has been implicated in the pathogenesis of bone metastases. Bone metastases are a significant complication in patients with prostate cancer. We compared the expression of PTHrP by immunohistochemical staining using a monoclonal antibody directed against epitope between amino acids [53–64] in benign prostatic hyperplasia (BPH) with that in various stages of prostate cancer. Tissue sections were obtained on formalin-fixed paraffin-embedded blocks from BPH, well-differentiated prostate cancer, poorly differentiated prostate cancer, lymph node metastases (n = 15 each), and normal prostate (n = 2). In the normal prostate tissue there was no staining observed. In BPH, 13 of 15 tissue samples were positive for PTHrP immunoreactivity. An average of 33% of the cells stained positive with 1+ intensity. All samples from prostate cancer stained positive for PTHrP. In the samples from well-differentiated prostate cancer, an average of 87% of cells stained positive for PTHrP, whereas 100% of cells were positive in poorly differentiated and metastatic tumors. The intensity of staining was 3+ in well-differentiated tumors and 4+ in poorly differentiated tumors. Therefore, the expression of PTHrP is enhanced in prostate cancer as compared with BPH and is greater in poorly differentiated carcinoma as compared with the well-differentiated tumors. The role of PTHrP in the pathogenesis of prostate cancer deserves further study.     

Antinociceptive and antidiarrheal effects of pioglitazone in a rat model of diarrhoea‐predominant irritable bowel syndrome: Role of nitric oxide

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Gemfibrozil,a lipid-lowering drug,improves hepatorenal damages in a mouse model of aging

Gemfibrozil (GFZ) is a medication of the fibrate category with agonistic effects on peroxisome proliferator-activated receptor-α (PPAR-α) and is effective for hypertriglyceridemia and mixed dyslipidemia. This agent also has anti-inflammatory and antioxidant properties. The current study investigated the effects of GFZ on hepatorenal damages in a D-galactose (D-gal)-induced aging model. We used 28 male mice, which were equally and randomly divided into four groups as follows: normal, D-gal (150 mg/kg/day; intraperitoneal [i.p.], for 6 weeks), GFZ (100 mg/kg/day GFZ, orally [p.o.] for 6 weeks), and the combined D-gal + GFZ. Liver and kidney function indices were measured as serum creatinine, blood urine nitrogen, alanine aminotransferase, and aspartate aminotransferase. Oxidative stress in hepatic and renal tissue was evaluated through malondialdehyde, superoxide dismutase, and glutathione peroxidase levels. Finally, the liver and kidney tissues were assessed for histopathological lesions. The results showed that D-gal-induced aging leads to abnormalities in liver and kidney function indices. D-gal also induced significant oxidative stress and histopathological lesions in these organs. GFZ improved function indices and oxidative stress compared to the D-gal-treated animals. Histological evaluations of the liver and kidney also confirmed these results. These data provide evidence for the potential therapeutic of GFZ in clinical practice for mitigating the hepatorenal damages of aging.     

Spotlight on 17‐AAG as an Hsp90 inhibitor for molecular targeted cancer treatment

Hsp90 is a ubiquitous chaperone with important roles in the organization and maturation of client proteins that are involved in the progression and survival of cancer cells. Multiple oncogenic pathways can be affected by inhibition of Hsp90 function through degradation of its client proteins. That makes Hsp90 a therapeutic target for cancer treatment. 17‐allylamino‐17‐demethoxy‐geldanamycin (17‐AAG) is a potent Hsp90 inhibitor that binds to Hsp90 and inhibits its chaperoning function, which results in the degradation of Hsp90's client proteins. There have been several preclinical studies of 17‐AAG as a single agent or in combination with other anticancer agents for a wide range of human cancers. Data from various phases of clinical trials show that 17‐AAG can be given safely at biologically active dosages with mild toxicity. Even though 17‐AAG has suitable pharmacological potency, its low water solubility and high hepatotoxicity could significantly restrict its clinical use. Nanomaterials‐based drug delivery carriers may overcome these drawbacks. In this paper, we review preclinical and clinical research on 17‐AAG as a single agent and in combination with other anticancer agents. In addition, we highlight the potential of using nanocarriers and nanocombination therapy to improve therapeutic effects of 17‐AAG.     

Selection for adjuvant chemotherapy in completely resected stage I non-small cell lung cancer: external validation of a Chinese prognostic risk model

Background

The ability to sub-stratify survival within stage I is an important consideration as it is assumed that survival is heterogeneous within this sub-group. Liang et al. recently published a nomogram to predict post-operative survival in patients undergoing lung cancer surgery. The aim of our study is external validation of their published nomogram in a British cohort focusing on stages IA and IB to determine applicability in selection of adjuvant chemotherapy within stage I.

Methods

Patient variables were extracted and the score individually calculated. Receiver operative characteristics curve (ROC) was calculated and compared with the original derivation cohort and the discriminatory ability was further quantified using survival plots by splitting our (external) validation cohort into three tertiles and Kaplan Meier plots were constructed and individual curves tested using Cox regression analysis on Stata 13 and R 3.1.2 respectively.

Results

A total of 1,238 patients were included for analysis. For all patients from stage IA to IIB the mean (SD) score was 9.95 (4.2). The ROC score comparing patients who died versus those that remained alive was 0.62 (95% CI: 0.58 to 0.67). When divided into prognostic score tertiles, survival discrimination remained evident for the entire cohort, as well as those for stage IA and IB alone. The P value comparing survival between the middle and highest score with baseline (low score) was P=0.031 and P=0.034 respectively.

Conclusions

Our results of external validation suggested lower survival discrimination than reported by the original group; however discrimination between survival remained evident for stage I.     

Modelling plastic scintillator response to gamma rays using light transport incorporated FLUKA code

The response function of NE102 plastic scintillator to gamma rays has been simulated using a joint FLUKA+PHOTRACK Monte Carlo code. The multi-purpose particle transport code, FLUKA, has been responsible for gamma transport whilst the light transport code, PHOTRACK, has simulated the transport of scintillation photons through scintillator and lightguide. The simulation results of plastic scintillator with/without light guides of different surface coverings have been successfully verified with experiments.