Effect of Finishing and Polishing on the Surface Roughness and Gloss of Feldspathic Ceramic for Chairside CAD/CAM Systems.

OBJECTIVES: To evaluate surface roughness and gloss of feldspathic ceramic blocks for chairside CAD/CAM systems before and after finishing and polishing. METHODS: VITA Mark II ceramic blocks for the CEREC CAD/CAM system were cut perpendicularly in order to obtain a total of 70 specimens (14 × 18 × 3 mm). The flat surface was roughened using a grinder/polisher with dry 120-grit silicone-carbide paper. Surface roughness and gloss were measured using a digital profilometer (Ra) and a glossmeter (GU), respectively. Specimens were randomly divided into seven groups (n=10) based on the finishing/polishing system as follows: 1) Identoflex NGPorcelain Polisher (INP), 2) Identoflex Diamond Ceramic Polisher (IDP), 3) Hiluster Polishing System (HPS), 4) OptraFine (OF), 5) Identoflex Lucent (IL), 6) VITA Akzent Glaze Spray (AGS), and 7) VITA Shading Paste and Liquid (SPL). Surface analysis was repeated after the finishing/polishing treatment, and the obtained data were compared to the baseline in order to evaluate the ΔRa and ΔGU. Results were statistically analyzed. The surface morphology was observed by scanning electron microscopy. RESULTS: The mean surface roughness of polished systems increased in the order (statistical groups designated) SPLa < ILa < OFab < IDPbc < AGSbc < INPbc < HPSc and mean gloss decreased in the order AGSa > SPLa > OFab > ILabc > HPSbcd > INPcd > IDPd. CONCLUSIONS: The smoothest surface of CAD/CAM feldspathic ceramic blocks was achieved using the furnace-based glaze systems VITA Akzent Glaze Spray and VITA Shading Paste and Liquid and manual systems Identoflex Lucent and OptraFine.

Thymidylate synthase level and DNA-ploidy pattern as possible prognostic factors in human colorectal cancer: a preliminary study.

5-Fluorouracil is the drug chosen for the treatment of patients with advanced colorectal carcinoma; its major site of action is thymidylate synthase (TS), resulting in pronounced and prolonged inhibition of DNA synthesis. The aim of this study was to evaluate the possibility of considering TS level in human colorectal carcinomas of previously untreated patients (pts) as a prognostic factor. Our data demonstrate that there is no association with age, sex, tumor site and tumor size; however, there is a relationship between TS levels and staging: in fact, the TS values are higher (P < 0.05) in Dukes-A tumors than in the others. A significant association was also found between the TS levels and survival parameters: in fact, pts with longer disease-free and overall survivals had a significantly increased TS level compared to pts with a poorer outcome (P < 0.05). Moreover, pts with DNA-aneuploid tumors had lower TS level (median = 0.044 pmol/mg protein) than diploid pts who had higher TS level (median = 0.093 pmol/mg protein); however the difference is not significant. Our result are based on preliminary data; however, they seem to support the hypothesis that a high TS level is a favourable prognostic factor in human colorectal carcinoma.

Failure of detection of the tyrosine to histidine substitution at the residue 33 of thymidylate synthase in human colorectal cancer. A preliminary study.

Structural changes in the macromolecular targets of pharmacological agents can result in alterations in the efficacy of these agents. In previous studies Berger et al. (1) identified a variant structural form of thymidylate synthase (TS) that is associated with relative resistance to 5-fluoro-2'-deoxyuridine, in a human colonic tumor cell line. They observed that expression of the variant TS, which differs from the normal form by a tyrosine to histidine substitution at residue 33, confers a 4-fold level of drug resistance in mammalian cells, as well as in bacteria. Now we report on the use of RT-PCR techniques to see if that variant TS form could be present in human samples from patients who underwent surgery for primary colorectal cancer and been previously untreated and to try to find relationships between that hypothetical variant TS form and the 5-Fluorouracil treatment. The possible role of Tyr-33 in 5-fluoropyrimidine-mediated inhibition of TS is discussed.

The role of thymidylate synthase levels in the prognosis and the treatment of patients with colorectal cancer.

Inhibition of Thymidylate Synthase (TS) by the 5-Fluorouracil (5Fu) active metabolite Fluoro-deoxy-uridine-monophosphate (FdUMP) is considered to be the main mechanism of action of 5Fu. TS level from tumors and normal mucosa of 62 untreated patients who underwent surgery for primary colorectal adenocarcinoma was performed. The aim of this study was to evaluate the possibility of considering the TS level as a prognostic factor of the disease. A large variation in the level of the enzyme was found among tumors. Our data demonstrate that there is no association with age, sex, and tumor size; however there are significant relationships between TS levels and staging and histological grading. In fact the TS values are higher in Dukes' A and in G1 than in Dukes' D and G3 tumors (p < 0.05). Another significant association has been found between the TS level and tumor site: pts with right colon neoplasias had higher TS levels than pts with left and rectum ones. An interesting trend was found between the TS levels and survival parameters. Pts who had lower TS levels had a significantly increased risk of death (p < 0.05) over pts with a higher outcome. Our data support the hypothesis that a high TS level is a favourable prognostic factor in human untreated colorectal carcinomas according to our previous preliminary data (1).

Concomitant cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy plus highly active antiretroviral therapy in patients with human immunodeficiency virus-related, non-Hodgkin lymphoma.

BACKGROUND: The feasibility and efficacy of concomitant chemotherapy and highly active antiretroviral therapy (HAART) is still unknown in patients with human immunodeficiency virus (HIV)-related malignancies. To evaluate the impact of chemotherapy plus HAART on the clinical course of patients with HIV-related, systemic, non-Hodgkin lymphoma (HIV-NHL), the authors compared retrospectively a group of 24 patients with HIV-NHL who were treated with the cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy regimen plus HAART with a group of 80 patients who were treated with CHOP chemotherapy or a CHOP-like regimen (i.e., cyclophosphamide, doxorubicin, teniposide, and prednisone with vincristine plus bleomycin) without receiving antiretroviral therapy. METHODS: All patients were enrolled in two sequential trials performed at the Aviano Cancer Center, Italy, from April 1988 to December 1998. HAART was included with combination therapy from January 1997. Antiretroviral regimens consisted of two reverse transcriptase inhibitors and one protease inhibitor. RESULTS: The two treatment groups were well matched with regard to patient demographics, NHL characteristics, HIV status, and treatment, i.e., the number of cycles and chemotherapy dose. The response rates were similar between the two groups. Severe anemia (Grade 3-4 according to the World Health Organization criteria) was significantly greater in the patients who received CHOP-HAART compared with the patients who received CHOP alone (33% vs. 7%, respectively; P = 0.001). Leukopenia was similar between the two groups, but colony stimulating factor support was significantly greater in the CHOP-HAART group than in the control group (92% vs. 66%, respectively; P = 0.03). Seventeen percent of CHOP-HAART patients developed severe autonomic neurotoxicity, whereas none of the CHOP patients developed neurotoxicity (P = 0.002). At similar median follow-up, opportunistic infection (OI) rates and mortality were significantly lower in the CHOP-HAART patients than in the CHOP patients (18% vs. 52%, respectively; P = 0.05; and 38% vs. 85%, respectively; P = 0.001). The median survival for CHOP-HAART patients was not reached, whereas the medial survival of CHOP patients was 7 months (P = 0.03). CONCLUSIONS: The combination of CHOP plus HAART is feasible and may reduce the morbidity from OIs in HIV-NHL patients. However, careful attention must be directed to cross toxicity and possible pharmacokinetic interactions between antiretroviral and antineoplastic drugs. The impact of the combined chemotherapy plus HAART treatment on patient survival needs urgently to be evaluated in prospective studies.