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• The approximability and the computational complexity of the Maximum Happy Set problem (MaxHS) are studied. • A (2 Δ + 1) -approximation algorithm for MaxHS on graphs with maximum degree Δ is presented. • The approximation ratio is improved to Δ if the maximum degree Δ is a constant. • The polynomial-time solvability of MaxHS on block/interval graphs is proved. • The NP-hardness of MaxHS on bipartite/cubic graphs is proved. In this paper we study the approximability of the Maximum Happy Set problem (MaxHS) and the computational complexity of MaxHS on graph classes: For an undirected graph G = (V , E) and a subset S ⊆ V of vertices, a vertex v is happy if v and all its neighbors are in S ; otherwise unhappy. Given an undirected graph G = (V , E) and an integer k , the goal of MaxHS is to find a subset S ⊆ V of k vertices such that the number of happy vertices is maximized. MaxHS is known to be NP-hard. In this paper, we design a (2 Δ + 1) -approximation algorithm for MaxHS on graphs with maximum degree Δ. Next, we show that the approximation ratio can be improved to Δ if the maximum degree Δ of the input graph is a constant. Then, we show that MaxHS can be solved in polynomial time if the input graph is restricted to block graphs, or interval graphs. We prove nevertheless that MaxHS on bipartite graphs or on cubic graphs remains NP-hard. [ABSTRACT FROM AUTHOR]

To determine whether the degree of oxidative DNA damage in renal cell carcinoma (RCC) can be used as a useful prognostic predictor for patients who undergo radical nephrectomy.We measured 8-hydroxy-2′-deoxyguanosine (8-OHdG), one of the most commonly used markers for evaluating oxidative stress, in DNA isolated from 72 RCC specimens, as well as adjacent normal kidney tissue using a quantitative sandwich enzyme-linked immunosorbent assay.The mean value of 8-OHdG in RCC was significantly greater than that in the adjacent normal tissue. The level of 8-OHdG in RCC compared with that in normal tissue (8-OHdG ratio) was significantly associated with other prognostic parameters, including mode of detection, maximal tumor size, distant metastasis, pathologic stage, tumor grade, and microscopic venous invasion. Furthermore, cancer-specific survival in patients with an elevated 8-OHdG ratio was significantly lower than that in patients with a normal 8-OHdG ratio; however, multivariate analysis using a Cox proportional hazards model showed that maximal tumor size and distant metastasis could be used as independent predictors of cancer-related death.These findings suggest that despite the lack of independent significance, the 8-OHdG ratio could be a useful prognostic indicator for patients with RCC; therefore, careful follow-up should be considered in those with an elevated 8-OHdG ratio. [Copyright &y& Elsevier]

Objectives. To compare the serum and urinary carcinoembryonic antigen (CEA) levels for assessment of possible risk of malignant transformation in patients with orthotopic neobladder.Methods. The serum and urinary levels of CEA, nutritional status, and acid-base and electrolyte balances were studied in 87 patients after radical cystectomy (22 with ileal neobladder, 28 with colon neobladder, and 37 with ileal conduit). The results of these groups were compared.Results. The serum CEA level in patients with colon neobladder, ileal neobladder, and ileal conduit was 5.4 ± 3.0, 3.7 ± 1.6, and 3.1 ± 1.5 ng/mL, respectively. The serum CEA level in the colon neobladder group was significantly higher than the levels in the remaining two groups (P <0.05); 16 patients (57%) with colon neobladder had elevated serum CEA values (ie, greater than 5 mg/mL). Elevated serum CEA was observed in only 5 (23%) and 3 (8%) patients with ileal neobladder or ileal conduit, respectively. The serum CEA value in these patients was associated with the urinary CEA value (P <0.001), but not the other factors examined.Conclusions. These findings suggest that colon bladder replacement caused significantly increased serum CEA values compared with ileal neobladder or ileal conduit; however, the elevated serum CEA level correlated with the urinary CEA level, irrespective of other clinical factors. Therefore, the elevated serum CEA in the colon neobladder group may have been due to reabsorption of CEA in urine rather than to an association with malignant changes in the bowel segments used for neobladder creation. [Copyright &y& Elsevier]