Analytical and Monte Carlo approaches to evaluate probability distributions of interruption duration

Regulatory authorities in many countries, in order to maintain an acceptable balance between appropriate customer service qualities and costs, are introducing a performance-based regulation. These regulations impose penalties-and, in some cases, rewards-that introduce a component of financial risk to an electric power utility due to the uncertainty associated with preserving a specific level of system reliability. In Brazil, for instance, one of the reliability indices receiving special attention by the utilities is the maximum continuous interruption duration (MCID) per customer.This parameter is responsible for the majority of penalties in many electric distribution utilities. This paper describes analytical and Monte Carlo simulation approaches to evaluate probability distributions of interruption duration indices. More emphasis will be given to the development of an analytical method to assess the probability distribution associated with the parameter MCID and the correspond ng penalties. Case studies on a simple distribution network and on a real Brazilian distribution system are presented and discussed.

IMMUNOHISTOCHEMICAL CHARACTERIZATION OF PROBABLE INTRAVASCULAR HEMATOPOIESIS IN THE VASA RECTAE OF THE RENAL MEDULLA IN ACUTE TUBULAR-NECROSIS

Immunohistochemistry was applied to identify the nature of the nucleated cells that accumulate in the vasa rectae of the corticomedullary junction in acute tubular necrosis. In all 6 cases studied, there were intravascular cells that reacted with monoclonal antibodies to erythroblast, macrophages, myeloid cells, T and B lymphocytes and rave megakaryocytes. The findings are consistent with the occurrence of intravascular haematopoiesis in the renal medulla in acute tubular necrosis.

P53 PROTEIN EXPRESSION AND NUCLEAR-DNA CONTENT IN BREAST INTRADUCTAL PROLIFERATIONS

Immunohistochemical analysis of the p53 gene protein and cytometric assessment of nuclear DNA were performed in a series of 51 cases of intraductal breast proliferation. The series included 22 cases of intraductal hyperplasia without atypia, 6 cases of intraductal hyperplasia with atypia, and 23 cases of pure intraductal carcinoma. Expression of p53 protein was detected in one case of intraductal hyperplasia without atypia (4.5 per cent), one case of intraductal hyperplasia with atypia (16.6 per cent) and six cases of intraductal carcinoma (26.0 per cent). No significant correlation was observed between p53 expression and histological subtype of intraductal carcinoma. Aneuploidy was demonstrated in two cases of intraductal hyperplasia with atypia (33.3 per cent) and in 18 cases of intraductal carcinoma (78.2 per cent). All cases of intraductal hyperplasia without atypia were euploid. No significant association was observed between p53 protein expression and ploidy in intraductal hyperplasia. The only case of intraductal hyperplasia without atypia positive for p53 was euploid, whereas the only p53-positive case of intraductal hyperplasia with atypia was aneuploid. Among the intraductal carcinomas, only the aneuploid cases showed positivity for p53, regardless of histological subtype. The results suggest that some of the changes observed in invasive breast carcinoma, such as p53 expression and aneuploidy, are already present in breast intraductal proliferation, especially in areas with atypia and in intraductal carcinoma. The expression of p53 in breast intraductal proliferation may reflect the acquisition of p53 gene mutations in cells unable adequately to repair DNA damage, with genomic instability which would lead to clonal expansion and putative evolution to invasive disease.

Estimation of growth fraction in fine needle aspirates from non-Hodgkin's lymphoma using anti-proliferating cell nuclear antigen - Correlation with the Kiel classification

OBJECTIVE: This study was undertaken to assess whether fine needle aspirates from non-Hodgkins lymphoma (NHL) could be used for growth fraction analysis with proliferating cell nuclear antigen (PCNA) staining and if there was a relationship between the growth fraction and cytomorphologic classification according to the Kiel classification.STUDY DESIGN: the study group consisted of 40 patients with NHL diagnosed by fine needle aspiration (FNA) cytology. The cytologic classification of the lymphomas was made by two cytopathologists on May-Grunwald-Giemsa-stained slides using the Kiel classification. There were 27 cases of low and 13 of high grade lymphoma. The estimation of the growth fraction was made by PCNA immunoreactivity. The PCNA index was quantitated in smears by counting an average of 1,000 cells, and the count teas correlated with the cytomorphologic classification.RESULTS: There was It strong correlation between the PCNA index and lymphoma grading. High grade lymphomas exhibited a mean PCNA positivity of 74.0%, which was significantly higher (P <.001) than that of low grade lymphomas (17.6%).CONCLUSION: Our study showed that PCNA evalua tion is suitable for smears obtained by FNA on NHL, correlates with increasing grades of lymphoma according to the Kiel classification and may offer a method of monitoring treatment of lymphoma.

CYTOMORPHOLOGICAL AND IMMUNOCYTOCHEMICAL EVALUATION OF FINE NEEDLE ASPIRATES FROM HIGH-GRADE NON-HODGKINS-LYMPHOMAS

1. Fine needle aspirates from ten patients with high-grade malignant non-Hodgkin's lymphomas were analyzed by cytomorphology and immunocytochemistry.2. The following morphologic diagnoses were made: lymphoblastic lymphoma (3 cases), Burkitt's lymphoma (3 cases), mixed small and large cell lymphomas with predominance of large cells (2 cases), and centroblastic lymphoma (2 cases). Immunocytochemistry showed a B-cell phenotype in five cases and a T-cell phenotype in four. One case of lymphoblastic lymphoma was negative for the T and B cell markers used.3. The results of histological and immunohistochemical analyses performed on surgical biopsies from 8 patients confirmed the morphological diagnosis in all cases. Two cases of Burkitt's lymphoma were submitted only to cytological and immunological diagnosis.4. The high diagnostic accuracy of combined cytomorphology and immunocytochemical assessment of fine needle aspirate samples validates the use of the technique in the diagnostic work-up of high-grade non Hodgkin's lymphomas.

Spectrum of carcinoembryonic antigen immunoreactivity from isolated ductal hyperplasias to atypical hyperplasias associated with infiltrating ductal breast cancer

Aims - To study the immunohistochemical expression of carcinoembryonic antigen (CEA) in ductal hyperplasia of the breast and to investigate its putative relation with atypia and co-existing infiltrating ductal carcinoma.Methods - Paraffin wax embedded tissue from 37 cases of isolated ductal hyperplasia (five with atypia and 32 without atypia) and 25 cases of ductal hyperplasia associated infiltrating ductal carcinoma (IDC) (seven with atypia and 18 without atypia) was stained with a monoclonal anti-CEA antibody using a standard avidin biotin immunoperoxidase method.Results - CEA immunoreactivity was observed in eight (12.8%) ductal hyperplasia cases. The percentage of CEA positivity in ductal hyperplasia cases with atypia (33.3%) was substantially higher than that observed in cases of ductal hyperplasia without atypia (8.0%). Six cases of ductal hyperplasia associated IDC reacted with CEA; in these six cases the neoplastic cells of the co-existing carcinoma were also CEA positive. The percentage of CEA immunoreactivity in ductal hyperplasia associated IDC was higher than that observed in isolated ductal hyperplasia (24.0 v 5.4%). The percentage of CEA immunoreactivity in atypical ductal hyperplasia associated IDC was similar to that observed in IDC alone (42.9 v 40.0%).Conclusions-The presence of CEA immunoreactivity has been confirmed in benign proliferative breast lesions. The prevalence of such immunoreactivity increases from 3.1% in isolated, nonatypical ductal hyperplasia to 42.9% in atypical ductal hyperplasia associated IDC. This finding and the similarity of the frequency of CEA positivity in atypical ductal hyperplasia associated IDC and in IDC alone suggests that there is a pathogenetic link between ductal hyperplasia and some types of breast cancer.

The proliferating cell nuclear antigen index in breast carcinomas does not correlate with mitotic index and estrogen receptor immunoreactivity

To investigate the expression of a marker of cell proliferation (PCNA/Cyclin) and its putative relationship with histological grading, mitotic index and estrogen receptor immunoreactivity, we studied twenty-seven cases of invasive breast carcinoma in formalin-fixed, paraffin-embedded tissue sections. The PCNA and estrogen receptor were detected by the PC10 and H222 monoclonal antibodies respectively, using an avidin-biotin-pernxidase method. The median value of PCNA index was 20.9% with a range from 1.4 to 84.2%. We did not find any significant relationship between PCNA index anti the histological grading, mitotic index and estrogen receptor immunoreactivity. We conclude that PCNA detected by the monoclonal antibody PC10 in formalin-fixed material looks at present unrealiable as a proliferation marker in breast carcinoma.

SINUS HISTIOCYTOSIS WITH MASSIVE LYMPHADENOPATHY (ROSAI-DORFMAN DISEASE) - CYTOMORPHOLOGIC ANALYSIS ON FINE-NEEDLE ASPIRATES

Cytomorphologic characteristics of smears from fine-needle aspirates (FNA) of three cases of sinus histiocytosis with massive lymphadenopathy (SHML) (Rosai-Dorfman disease) are described. All aspirates showed mature lymphocytes, plasma cells, and large pale histiocytes with well-preserved lymphocytes within the cytoplasm (lymphocytophagocytosis). The cases were confirmed by surgical biopsy, and the immunohistochemical findings suggested a macrophage origin for this lesion. The value of FNA analysis as an aid to diagnosis of SHML is discussed.

ALTERED FOCI OF HEPATOCYTES IN RATS INITIATED WITH DIETHYLNITROSAMINE AFTER PROLONGED FASTING

The influence of fasting on the potential of diethylnitrosamine (DEN) to initiate liver cucinogenesis was tested in a medium-term assay using the development of putative preneoplastic altered foci of hepatocytes (AFH) as the endpoint. Male Wistar rats fasted for 48 hr were given a single ip injection of DEN (200 mg/kg body weight). Partial hepatectomies were carried out at wk 3 and the rats were killed at wk 8. Fasted rats exhibited a small increase in the numbers of AFH with glutathione S-transferase in the placental form and eosinophilic AFH when compared with non-fasted animals. However, after a 6-wk exposure to 0.05% sodium phenobarbital in the diet, there were no differences in the numbers of AFH between fasted and non-fasted animals. Fasting also increased DEN-dependent centrilobular cell necrosis and specifically drug metabolism as indicated in vivo by a decreased time of paralysis of the lower limbs induced by zoxazolamine (40 mg/kg body weight, ip) and by an unaltered sleeping time induced by sodium pentobarbital (40 mg/kg body weight, ip). The results indicate that although fasting during the initiation stage of carcinogenesis increases DEN hepatotoxicity, it does not interfere quantitatively with the development of liver preneoplastic lesions.

Differential response of the luteal phase and fertility in cattle following ovulation of the first-wave follicle with human chorionic gonadotropin or an agonist of gonadotropin-releasing hormone

A series of experiments with Holstein heifers was conducted to develop the capability of inducing accessory corpus luteum (CL) with a GnRH agonist (Buserelin, 8 mu g; GnRHa) or hCG; (3,000 IU) to increase plasma progesterone concentrations (Exp. 1, 2, and 3) and to test whether induction of accessory CL with hCG will increase conception rates in heifers (Exp. 4) and lactating cows (Exp. 5). In Exp. 1, heifers were treated on d 5 after estrus with GnRHa (n = 8) or saline (n = 7); heifers in Exp. 2 received hCG (n = 5) or saline (n = 4) on d 5. Experiment 3 allowed a contemporary evaluation of heifers treated on d 5 with GnRHa (n = 6), hCG (n = 6), saline (n = 6), or GnRHa at d 5 and hCG at the time of the induced ovulation (n = 5). The GnRHa and hCG were equally effective in inducing an accessory CL (93% induction rate), but the subsequent increase in progesterone concentrations was greater in hCG-treated heifers. A greater half life of hCG may provide longer LH-like stimulation of the first-wave follicle and subsequent developing accessory CL or a greater luteotropic effect on the original CL. Induction of an accessory CL with hCG on d 5 or 6 after insemination did not increase pregnancy rates in fertile heifers (Exp. 4: hCG = 64.8% vs control = 62.9%; n = 243) or lactating dairy cows during summer heat stress (Exp. 5: hCG = 24.2% vs control = 23.5%; n = 201).

Reappraisal of immunohistochemical profiling of special histological types of breast carcinomas: a study of 121 cases of eight different subtypes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)