Tribological Performance Investigation of a Commercial Engine Oil Incorporating Reduced Graphene Oxide as Additive.

We investigated the tribological behavior of commercialized, fully synthetic engine oil upon the incorporation of reduced graphene oxide in seven different concentrations between 0.01 and 0.2 wt %. Stability of the prepared samples was assessed by turbidimetry and dynamic light scattering measurements, and their tribological properties through a reciprocating tribometer, using a steel ball on special cut steel blocks. The addition of 0.02 wt % of reduced graphene oxide led to an improvement of the tribological behavior compared to the pristine engine oil, by significantly lowering the friction coefficient by 5% in the boundary lubrication regime. Both the surfaces and the reduced graphene oxide additive were thoroughly characterized by microscopic and optical spectroscopy techniques. We also verified that a protective layer was formed between the worn surfaces, due to the presence of reduced graphene oxide. Carbon accumulation and various additive elements such as Ca, Zn, S and P were detected on the rubbing surfaces of both the ball and the block through energy-dispersive X-ray spectroscopy. Finally, it was shown that the wear scar diameter on the surface of the steel ball was lower by 3%, upon testing the engine oil sample containing reduced graphene oxide at concentration 0.02 wt %, compared to the control sample.

Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) of the penis.

Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) of the penis has been very rarely defined. We report a case of a 19-year-old patient with a tumor, localized in the dorsal side of penis, composed of small round cells with diffuse membranous mic-2 (CD99) immunopositivity. The patient was treated with multiagent chemotherapy and radiotherapy.

Successful therapy of systemic xanthogranuloma in a child.

Systemic juvenile xanthogranuloma is a rare disease in children. A 10-year-old boy who showed renal, pulmonary, and liver involvement is reported. He had pulmonary invasion, renal mass, and nodular liver lesions but no bone involvement. The diagnosis was confirmed by renal biopsy, which revealed foamy, lipid-laden macrophages with positive CD68, but negative CD1a and S-100. The patient was treated with pulse high-dose methylprednisolone (10 mg/kg/d for 3 d for 6 courses). On 1-year follow-up period after 6 courses therapy was resulted in remarkable regression in renal and liver lesions.

The prognostic significance of angiogenesis and the effect of vascular endothelial growth factor on angiogenic process in Wilms' tumour.

AIMS: There is a subgroup of patients with Wilms' tumour (WT) having favourable clinicopathological features but adverse outcome. We aimed to investigate the prognostic significance of angiogenesis and whether it can be used for predicting which patients will fall into this category, and the possible role of vascular endothelial growth factor (VEGF) on angiogenesis in WT. METHODS: Tumours in nephrectomy specimens from 63 WT patients were investigated for neovascularisation and VEGF expression by immunohistochemistry. The endothelial cells were highlighted by anti-CD34 and anti-CD31, and the microvessels in the hot-spots were counted. Correlations between the microvessel density (MVD), VEGF expression, clinicopathological features and prognosis were studied. RESULTS: Among 21 patients with follow-up data, favourable histology was detected in 17, seven of which died of disease. Patients with highly vascular tumours showed significantly poorer prognosis than those with low vascular tumours. There was no significant relationship between angiogenesis and VEGF expression. VEGF immunostaining revealed various patterns in different components of WT. CONCLUSIONS: We suggest that high MVD can be used as an indicator of poor prognosis with WT patients displaying favourable histology and there might be some additional growth factors other than VEGF which may also be responsible for angiogenesis in WTs.

Can renal oncocytoma be differentiated from its renal mimics? The utility of anti-mitochondrial, caveolin 1, CD63 and cytokeratin 14 antibodies in the differential diagnosis.

Among the epithelial renal tumours with eosinophilic cytoplasm, the main differential diagnostic problem arises between renal oncocytomas (ROs) and eosinophilic variants of chromophobe renal cell carcinomas (RCCs). We investigated the possible role of anti-mitochondrial (AMA), anti-caveolin 1 (CAV1), anti-CD63 (CD63) and anti-cytokeratin 14 (CK14) antibodies in the differential diagnosis of eosinophilic epithelial tumours and applied the Muller and Mowry modification of Hale's colloidal iron stain (HCI). Thirty-five ROs and 77 eosinophilic RCCs (27 chromophobe, 28 clear cell and 22 papillary RCCs) were included in this study. Apical and/or polar CD63 immunostaining (94%) and diffuse AMA (91%) and CAV1 (88%) immunostainings were the characteristics of ROs, whereas diffuse CD63 immunostaining (96%) and diffuse-peripheral AMA (96%) and CAV1 (92%) immunostainings were characteristic immunohistochemical features of eosinophilic chromophobe RCCs. We showed CK14 antibody not to be useful in the differential diagnosis of the eosinophilic epithelial renal tumours. The staining localisations with AMA, CAV1 and CD63 antibodies were significantly different between tumour groups. AMA had 96% sensitivity and 94% specificity, whereas CAV1 had 92% sensitivity and 97% specificity in diagnosing chromophobe RCCs. With HCI staining, ROs, showing apical and/or polar staining, could be differentiated from chromophobe RCCs, showing diffuse cytoplasmic staining. HCI had fairly low (69%) sensitivity and 100% specificity, whereas CD63 had 95% sensitivity and 100% specificity to diagnose ROs. We recommend using CD63 as the best marker of choice for distinguishing ROs from eosinophilic chromophobe RCCs when standard diagnostic criteria are not helpful.

Should high-grade prostatic intraepithelial neoplasia change our approach to infravesical obstruction?

OBJECTIVES: To investigate whether coexistence of high-grade prostatic intraepithelial neoplasia (HPIN) should change our therapeutic approach to infravesical obstruction. MATERIAL AND METHODS: Of 505 patients who underwent sextant transrectal ultrasonography (TRUS)-guided prostate biopsy, 65 (12.8%) had HPIN and 29 of them underwent prostatectomy (23 transurethral resection of prostate (TURP), 6 open) due to obstructive urinary symptoms. Patients without carcinoma were followed up with semiannual prostate-specific antigen (PSA) and digital rectal examination. After a follow-up of 24.8 +/- 11.0 months, 19 of 29 patients who accepted our call had another sextant biopsy. RESULTS: Mean age and initial mean PSA values of 29 patients were 67.6 +/- 6.7 years and 9.26 +/- 5.91 ng/ml, respectively. The final pathological evaluation of the surgical specimens revealed 2 prostatic adenocarcinomas both in the TURP group. The remaining 27 (93.2%) patients were found to have benign prostatic hyperplasia (BPH) and their serum PSA levels declined from 9.26 +/- 5.91 to 4.59 +/- 2.0 ng/ml 3 months after prostatectomy. Of the 19 patients who had another biopsy with a mean PSA value of 4.06 +/- 4.61 ng/ml, 15 and 4 of them had BPH and HPIN respectively. CONCLUSIONS: Our preliminary data indicate that the presence of HPIN on TRUS-guided biopsies is not a factor to delay an indicated surgical intervention for infravesical obstruction.

Impact of p53 and Ki-67 in predicting recurrence and progression of superficial (pTa and pT1) urothelial cell carcinomas of urinary bladder.

In predicting the aggressive behavior of bladder tumors, the histopathological characteristics of grade and invasive stage are of principal importance. However, for predicting tumor recurrence and progression, these are sufficient only to a limited extent, particularly in the case of superficial (pTa and pT1) urothelial cell carcinomas. New prognostic factors are therefore needed to avoid either insufficient or excessive treatment. In this retrospective study, we investigated the prognostic value of the p53 and Ki-67 immunoreactivity indices. The present study included 118 superficial urinary bladder tumors consisting of 58 recurrent and 60 non-recurrent cases. Twenty of the recurrent tumors progressed into a higher grade and/or invasive stage. Paraffin immunohistochemical analysis was carried out using anti-p53 and anti-Ki-67 antibodies on the initial tumor tissues. We concluded that there is a highly significant relationship between the p53 and Ki-67 immunoreactivities and the histological grade and pathological stage of the tumors (P < 0.0001). We observed a significant relationship between the presence of recurrence and progression and the p53 immunoreactivity index (P < 0.01 and P = 0.017, respectively) and Ki-67 immunoreactivity index (P < 0.0001 and P = 0.046, respectively). Positivity for p53 and Ki-67 can demonstrate the risk of recurrence (p53: sensitivity = 76%, specificity = 58%; Ki-67: sensitivity = 86%, specificity = 48%) and progression (p53: sensitivity = 80%, specificity = 46%; Ki-67: sensitivity = 85%, specificity = 36%; ). We believe that both of these immunohistochemical markers can be considered valuable in addition to classical histopathological prognostic parameters for predicting recurrence and progression risks.