Distinguishing benign from malignant parotid gland tumours: low-dose multi-phasic CT protocol with 5-minute delay

Objectives

To explore the percentage enhancement wash-out ratio (PEW) and relative PEW (RPEW) of low-dose multi-phasic computed tomography (CT) in distinguishing benign from malignant parotid gland tumours.

Methods

This study was approved by the ethics committee, and informed patient consent was obtained. 51 patients with parotid tumours proven by histopathology received CT, including 18 with pleomorphic adenomas, 14 with Warthin’s tumours and 19 with malignant tumours. Size and attenuation of parotid tumours were measured. Compared with 5-min attenuation, the 30-s and 90-s PEW (PEW_30, PEW₉₀) and RPEW (RPEW₃₀, RPEW₉₀) were calculated.

Results

There was a significant difference in PEW₃₀, RPEW₃₀, PEW₉₀ and RPEW₉₀ in the parotid neoplasms groups (P < 0.01), and statistical significance existed simultaneously in pleomorphic adenomas vs malignant tumours and Warthin’s tumours vs malignant tumours according to SNK-q test. The optimal diagnosis results of malignancy with 100% specificity (32/32) was obtained by using a combination of the following criteria: −70% > PEW₃₀ < 36%, −30% > PEW₃₀ < 19%, PEW₉₀ > 12%, and the sensitivity (74%) for diagnosis of malignancy was yield.

Conclusions

Wash-out ratio may assist in differentiating the benign from malignant parotid gland tumours. Combining the percentage of enhanced wash-out ratios of CT protocols can yield diagnostic results for malignancy.

Involvement of Cyr61 in growth, migration, and metastasis of prostate cancer cells

Cyr61 has been reported to participate in the development and progression of various cancers; however, its role in prostate cancer (PCa) still remains poorly understood. In this study, we explored the function of Cyr61 in a series of malignant PCa cell lines, including LnCap, Du145, and PC3. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet assays demonstrated that Cyr61 was essential for the proliferation of PCa cells. Soft agar assay and xenograft analysis showed that downregulation of Cyr61 suppressed the tumorigenicity of Du145 cells both in vitro and in vivo. Either silencing the cellular Cyr61 by RNA interference or neutralising the endogenous Cyr61 by antibody inhibited the migration of Du145 cells. In contrast, purified protein of Cyr61 promoted the migration of LnCap cells in a dose-dependent manner. These results suggested that Cyr61 was involved in the migration of PCa cells. We also observed the accumulation of mature focal adhesion complexes associated with the impaired migration through Cyr61 downregulation. Also, further studies showed that Cyr61 regulated the level of activated Rac1 as well as its downstream targets, including phosphorylated JNK, E-cadherin, and p27^kip1, which are key molecules involved in cell growth, migration, and invasion. The in vivo mouse tail vein injection experiment revealed that Cyr61 affected the metastatic capacity of Du145 cells, suggesting that Cyr61 was required for prostate tumour metastasis. Altogether, our results demonstrated that Cyr61 played an important role in the tumorigenicity and metastasis of PCa cells, which will benefit the development of therapeutic strategy for PCas.

LAI inversion algorithm based on directional reflectance kernels

Leaf area index (LAI) is an important ecological and environmental parameter. A new LAI algorithm is developed using the principles of ground LAI measurements based on canopy gap fraction. First, the relationship between LAI and gap fraction at various zenith angles is derived from the definition of LAI. Then, the directional gap fraction is acquired from a remote sensing bidirectional reflectance distribution function (BRDF) product. This acquisition is obtained by using a kernel driven model and a large-scale directional gap fraction algorithm. The algorithm has been applied to estimate a LAI distribution in China in mid-July 2002. The ground data acquired from two field experiments in Changbai Mountain and Qilian Mountain were used to validate the algorithm. To resolve the scale discrepancy between high resolution ground observations and low resolution remote sensing data, two TM images with a resolution approaching the size of ground plots were used to relate the coarse resolution LAI map to ground measurements. First, an empirical relationship between the measured LAI and a vegetation index was established. Next, a high resolution LAI map was generated using the relationship. The LAI value of a low resolution pixel was calculated from the area-weighted sum of high resolution LAIs composing the low resolution pixel. The results of this comparison showed that the inversion algorithm has an accuracy of 82%. Factors that may influence the accuracy are also discussed in this paper.

Restricted intake of dietary advanced glycation end products retards renal progression in the remnant kidney model

Diet-derived advanced glycation end products (AGEs) contribute significantly to accumulation of AGEs in renal insufficiency. To test whether modulation of dietary AGEs would impact on progression of chronic renal disease, 5/6 nephrectomy rats were randomly placed on three diets that differed only in AGEs content (low AGEs diet (LAD), high AGEs diet (HAD), and standard rodent diet (SRD)) for 5-13 weeks. Compared with SRD- or HAD-fed rats, LAD-treated animals showed decreased proteinuria and retarded decline of creatinine clearance without alteration of blood pressure. Glomerular volume was reduced by 23% compared with HAD-fed rats at week 13 (P<0.001). Renal fibrosis progressed with time in the remnant kidneys from HAD-fed rats. However, LAD-fed animals presented a better-preserved structure of the kidneys. LAD-fed rats demonstrated significantly decreased serum and renal AGEs concentration (P<0.01 and P<0.01). This was associated with marked decrease of intrarenal advanced oxidation protein products and thiobarbituric acid reactive substances, as well as increase of glutathione peroxidase activity. LAD treatment also downregulated expression of monocyte chemoattractant protein-1 and transforming growth factor-1 and ameliorated macrophage infiltration in the remnant kidney. These results demonstrated that restriction of dietary AGEs intake retards progression of renal fibrosis and dysfunction in the remnant kidney model.

Protective Effect of Gui Qi Mixture on the Progression of Diabetic Nephropathy in Rats

Huang Qi (root of Astragalus membranaceus) and Dang Gui ( Angelica sinensis), two of the most widely used herbs in traditional Chinese medicine, have been proven to be effective in the treatment of diabetes mellitus (DM) although the underlying molecular mechanisms are not fully elucidated. This study was designed to investigate the protective effect of Dang Gui and Huang Qi mixture (GQM) on the development of diabetic nephropathy in rats with streptozotocin (STZ)-induced DM and the possible underlying molecular mechanism. The diabetic animal model was made by a single intraperitoneal injection of STZ and then treated with GQM or benazepril. Blood glucose, triglyceride (TG), cholesterol (CHO), high density lipoprotein (HDL), serum creatinine (Scr), creatinine clearance rate (Ccr), blood urea nitrogen (BUN), urine beta (2)-microglobin (beta (2)-MG), kidney/body weight (K/B) ratio, glomerular area (GA), renal transforming growth factor-beta (1) (TGF-beta (1)) mRNA expression and blood and renal angiotensin II (AngII) expression were determined 8 weeks after the treatment. The blood glucose, CHO and TG levels, BUN, SCr, Ccr. K/B ratio, GA, the excretion of beta (2)-MG, renal TGF-beta (1) mRNA expression and blood and renal AngII expression were significantly increased while the HDL level was decreased 8 week after STZ injection. The changes in blood glucose, TG, CHO and HDL were reversed by GQM, not by benazepril, whereas the changes in other variables were reversed by both GQM and benazepril. Our results suggest that GQM alleviates the disorder in blood glucose and lipids, protects against the progression of renal nephropathy in diabetic rats, probably by inhibiting the expression of AngII and TGF-beta (1) mRNA.

Unscheduled CDK1 activity in G1 phase of the cell cycle triggers apoptosis in X-irradiated lymphocytic leukemia cells

Cyclin-dependent kinase 1 (CDK1) is a major component of the cell cycle progression engine. Recently, several investigations provided evidence demonstrating that unscheduled CDK1 activation may also be involved in apoptosis in cancerous cells. In this article, we demonstrate that X-ray irradiation induced G1 arrest in MOLT-4 lymphocytic leukemia cells, the arrest being accompanied by reduction in the activity of CDK2, but increased CDK1 activity and cell apoptosis in the G1 phase. Interestingly, this increase in CDK1 and apoptosis by ionizing radiation was prevented by pretreatment with the CDK1 inhibitor, roscovitine, suggesting that CDK1 kinase activity is required for radiation-induced apoptotic cell death in this model system. Furthermore, cyclin B1 and CDK1 were detected co-localizing and associating in G1 phase MOLT-4 cells, with the cellular lysates from these cells revealing a genotoxic stress-induced increase in CDK1 phosphorylation (Thr-161) and dephosphorylation (Tyr-15), as analyzed by postsorting immunoprecipitation and immunoblotting. Finally, X-irradiation was found to increase Bcl-2 phosphorylation in G1 phase cells. Taken together, these novel findings suggest that CDK1 is activated by unscheduled accumulation of cyclin B1 in G1 phase cells exposed to X-ray, and that CDK1 activation, at the wrong time and in the wrong phase, may directly or indirectly trigger a Bcl-2-dependent signaling pathway leading to apoptotic cell death in MOLT-4 cells.

DLK1: increased expression in gliomas and associated with oncogenic activities

DLK1 (delta-like) is a transmembrane and secreted protein in the epidermal growth factor-like homeotic family. Although expressed widely during embryonic development, only a few tissues retain the expression in adults. Neuroendocrine tumors often highly express this protein; therefore, we hypothesized that brain tumors might also express it. This study found that the expression of DLK1 in gliomas was higher than that in normal brain (P < 0.05). After stable transfection of a DLK1 cDNA expression vector into GBM cell lines, their proliferation was increased. Furthermore, they lost contact inhibition, had enhanced anchorage-independent growth in soft agar, and had significantly greater capacity to migrate. Western blot studies showed that expression of cyclin D1, CDK2, and E2F4 were increased, and Rb levels were decreased in these cells. DLK1 was found on the cell surface and secreted in the medium from the transfected GBM cells. DLK1-enriched condition medium stimulated the growth of glioblastoma multiforme cell lines and explants. DLK1 antibody blocked cell growth stimulated by DLK1. In summary, these results suggest that DLK1 may play a role in the formation or progression of gliomas.