The hemolytic component of cancer anemia: effects of osmotic and metabolic stress on the erythrocytes of rats bearing multifocal inoculations of the Walker 256 tumor

Cancer anemia is classified as an anemia of chronic diseases, although it is sometimes the first symptom of cancer. Cancer anemia includes a hemolytic component, important in the terminal stage when even transfused cells are rapidly destroyed. The presence of a chronic component and the terminal complications of the illness limit studies of the hemolytic component. A multifocal model of tumor growth was used here to simulate the terminal metastatic dissemination stage (several simultaneous inoculations of Walker 256 cells). The hemolytic component of anemia began 3-4 days after inoculation in 100% of the rats and progressed rapidly thereafter: Hb levels dropped from 14.9 ± 0.02 to 8.7 ± 0.06 from days 7 to 11 (~5 times the physiologically normal rate in rats) in the absence of bleeding. The development of anemia was correlated (r2 = 0.86) with the development of other systemic effects such as anorexia. There was a significant decrease in the osmotic fragility of circulating erythrocytes: the NaCl concentration causing 50% lysis was reduced from 4.52 ± 0.06 to 4.10 ± 0.01 (P<0.01) on day 7, indicating a reduction in erythrocyte volume. However, with mild metabolic stress (4-h incubation at 37oC), the erythrocytes showed a greater increase in osmotic fragility than the controls, suggesting marked alteration of erythrocyte homeostasis. These effects may be due to primary plasma membrane alterations (transport and/or permeability) and/or may be secondary to metabolic changes. This multifocal model is adequate for studying the hemolytic component of cancer anemia since it is rapid, highly reproducible and causes minimal animal suffering

C. USSING. Den faste Voldgiftsret i Danmark. Norsk Forening socialt Arbejde. Kristiania 1915.

Cancer anemia is classified as an anemia of chronic diseases, although it is sometimes the first symptom of cancer. Cancer anemia includes a hemolytic component, important in the terminal stage when even transfused cells are rapidly destroyed. The presence of a chronic component and the terminal complications of the illness limit studies of the hemolytic component. A multifocal model of tumor growth was used here to simulate the terminal metastatic dissemination stage (several simultaneous inoculations of Walker 256 cells). The hemolytic component of anemia began 3-4 days after inoculation in 100% of the rats and progressed rapidly thereafter: Hb levels dropped from 14.9 ± 0.02 to 8.7 ± 0.06 from days 7 to 11 (~5 times the physiologically normal rate in rats) in the absence of bleeding. The development of anemia was correlated (r2 = 0.86) with the development of other systemic effects such as anorexia. There was a significant decrease in the osmotic fragility of circulating erythrocytes: the NaCl concentration causing 50% lysis was reduced from 4.52 ± 0.06 to 4.10 ± 0.01 (P<0.01) on day 7, indicating a reduction in erythrocyte volume. However, with mild metabolic stress (4-h incubation at 37oC), the erythrocytes showed a greater increase in osmotic fragility than the controls, suggesting marked alteration of erythrocyte homeostasis. These effects may be due to primary plasma membrane alterations (transport and/or permeability) and/or may be secondary to metabolic changes. This multifocal model is adequate for studying the hemolytic component of cancer anemia since it is rapid, highly reproducible and causes minimal animal suffering

The hemolytic component of cancer anemia: effects of osmotic and metabolic stress on the erythrocytes of rats bearing multifocal inoculations of the Walker 256 tumor

Cancer anemia is classified as an anemia of chronic diseases, although it is sometimes the first symptom of cancer. Cancer anemia includes a hemolytic component, important in the terminal stage when even transfused cells are rapidly destroyed. The presence of a chronic component and the terminal complications of the illness limit studies of the hemolytic component. A multifocal model of tumor growth was used here to simulate the terminal metastatic dissemination stage (several simultaneous inoculations of Walker 256 cells). The hemolytic component of anemia began 3-4 days after inoculation in 100% of the rats and progressed rapidly thereafter: Hb levels dropped from 14.9 ± 0.02 to 8.7 ± 0.06 from days 7 to 11 (~5 times the physiologically normal rate in rats) in the absence of bleeding. The development of anemia was correlated (r2 = 0.86) with the development of other systemic effects such as anorexia. There was a significant decrease in the osmotic fragility of circulating erythrocytes: the NaCl concentration causing 50% lysis was reduced from 4.52 ± 0.06 to 4.10 ± 0.01 (P<0.01) on day 7, indicating a reduction in erythrocyte volume. However, with mild metabolic stress (4-h incubation at 37oC), the erythrocytes showed a greater increase in osmotic fragility than the controls, suggesting marked alteration of erythrocyte homeostasis. These effects may be due to primary plasma membrane alterations (transport and/or permeability) and/or may be secondary to metabolic changes. This multifocal model is adequate for studying the hemolytic component of cancer anemia since it is rapid, highly reproducible and causes minimal animal suffering

Dengue Fever: A Post-epidemic Seroepidemiological Survey In An Urban Setting At A Northwestern County Of S. Paulo State - Brazil [dengue: Inquérito Sorológico Pós-epidêmico Em Zona Urbana Do Estado De São Paulo (brasil)]

Objective The objective of this study was to evaluate the real size of the epidemics registered in the urban area of the county of Santa Bárbara D'Oeste, SP, Brazil, from April to June, 1995. The measurement of the epidemiological validity of the official surveillance system criteria and its positive predicted value were adopted as specific goals. Methods A sero-epidemiological survey was carried out over a sample of 1,113 sera from citizens of Santa Barbara D 'Oeste, through a systematic random sampling of houses, five months after the end of the epidemics. Infection rates were compared with the infestation indexes by Aedes aegipty and the notified cases amongst the county sections. The importance of submitting patients with clinical suspicion of dengue to laboratory tests was discussed. Results and Discussion It was found that infection rates by dengue virus varied in the same direction and proportion as the presence of Aedes aegipty larvae reported by the "Breteau Index", as well as the number of cases reported by the official notifiable diseases surveillance system during the epidemics. A prevalence of 630 by 100 thousand inhabitants was found, a 15-fold rate when compared to the laboratory positive sera from cases detected by the surveillance system during the epidemics. A retrospective comparison with the surveillance reports, using serological results as a gold standard, also showed that the majority of dengue specific serum-positive individuals were not detected during the epidemics, otherwise cases that did not present serological reaction were notified exhibiting a low positive predictive value of clinical diagnosis (15,6).336566574Alves, M.C.G.P., Gurgel, S.M., Almeida, M.M.C.R.R., Plano amostral para cálcule de densidade larvária de Aedes aegypti e Aaedes albopictus no Estado de São Paulo, Brasil (1991) Rev Saúde Pública, 25, pp. 251-256(1996) Bol Inform, 11 (47). , maioDietz, V.J., Gubler, D.J., Rigau-Perez, J.G., Pinheiro, F., Schatzmayr, H.G., Bailey, R., Epidemic dengue 1 in Brazil, 1986: Evaluation of a clinically based dengue surveillance system (1990) Am J Epidemiol, 131, pp. 693-700Figueiredo, L.T.M., Rosa, A.P.A.T., Fiorillo, A.M., Níveis de anticorpos para arbovírus em indivíduos da região de Ribeirão Preto, SP (Brasil) (1986) Rev Saúde Pública, 20, pp. 204-211Figueiredo, L.T.M., (1994) Estudos Sobre o Dengue Em Ribeiräo Preto 1990-1993, , [dissertação] Ribeirão Preto (SP): Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo;Figueiredo, L.T.M., Abe Owa, M., Carlucci, R.H., Dal Fabero, A.L., Mello, N.Vd., Capuano, D.M., Encuesta serológica sobre el dengue en Ribeirão Preto, São Paulo, Brasil (1995) Bol Oficina Sanit Panam, 118, pp. 499-509Guzmán, M.G., Kouri, G.P., Bravo, J., Soler, M., Vasquez, S., Morier, L., Dengue hemorrhagic fever in Cuba, 1981: A retrospective seroepidemiologic study (1990) Am J Trop Med Hyg, 42, pp. 179-184Halstead, S.P., Global epidemiology of dengue hemorrhagic fever (1990) Southeast Asian J Trop Med Public Health, 21, pp. 636-641Johnson, K.M., Halstead, S.B., Cohen, S.N., Hemorrhagic fever of Southeast Asia and South America: A comparative appraisal (1967) Prog Med Virol, 9, pp. 105-158Kuno, G., Gómez, I., Gubler, D.J., Detecting artificial antidengue IgM immune complexes using an enzyme-linked immunosorbent assay (1987) Am J Trop Med Hyg, 36, pp. 153-159(1987) Dengue Hemorrágico: Diagnóstico, Tratamento e Controle, , GenebraResurgimiento del dengue en las Américas (1997) Bol Epidemiol, 18 (2)Shope, R.E., Sather, G.E., Arboviruses (1979) Diagnostic Procedures for Viral, Rickettsial and Chlamydial Infections. 5th Ed., pp. 767-814. , Lennete EH, Schimidt NJ, editors Washington (DC): American Public Health Association(1997) Inf Epidemiol SUS, 6 (1)Theiler, M., Downs, W.C., (1973) The Arthropod-borne Viruses of Vertebrates, pp. 62-91. , New Haven: Yale University PressTirado, M.G.G., Flores, G.K., Gonzalez, J.B., Silva, L.C., Ramudo, S., Encuesta serológica nacional a virus dengue. Cuba 1982 (1984) Rev Cub Med Trop, 36, pp. 124-13

Tumor growth characteristics of the Walker 256 AR tumor, a regressive variant of the rat Walker 256 A tumor

The present study aimed at characterizing the subcutaneous development of the Walker 256 (W256) AR tumor, a regressive variant of the rat W256 A tumor. Wistar rats were injected subcutaneously with 4x10(6) W256 A or W256 AR tumor cells. The development of tumors was evaluated daily by percutaneous measurements. None of the W256 A tumors (n=20) regressed, but 62% of the W256 AR tumor-bearing rats (n=21) underwent complete tumor regression within 35 days. Continuous growth of AR tumors was characterized by an increase of the tumor growth rate from day 12, which reached values above 1.0 g/day, and were significantly higher (p<0.05) than those of the regressive AR tumors. Immunosuppression by irradiation before subcutaneous injection of AR cells completely abrogated tumor regression and was associated with severe metastatic dissemination. Daily evaluation of the tumor growth rate enabled the discrimination, in advance, between continuously growing tumors and those that regressed later on.<br>O objetivo neste estudo foi caracterizar o desenvolvimento subcutâneo do tumor de Walker 256 (W256) AR, uma variante regressiva do tumor de W256 A de rato. Ratos Wistar foram injetados com 4x10(6) células tumorais de W256 A ou W256 AR. O desenvolvimento tumoral foi avaliado diariamente. Nenhum dos tumores W256 A (n=20) regrediu, mas 62% dos ratos com tumor W256 AR apresentaram regressão completa dos tumores em até 35 dias. O crescimento contínuo dos tumores AR foi caracterizado pelo aumento da taxa de crescimento tumoral a partir do dia 12, alcançando valores maiores que 1,0g/dia, que foram significativamente superiores (p<0,05) aos valores de taxa de crescimento dos tumores regressivos AR. A imunossupressão por irradiação precedendo a injeção das células tumorais AR eliminou completamente a regressão tumoral e favoreceu disseminação metastática severa. Este estudo caracterizou o desenvolvimento do tumor de W256 AR em condições específicas, documentando a regressão espontânea deste tumor após a injeção subcutânea de altas doses de células tumorais em ratos Wistar. A avaliação diária da taxa de crescimento tumoral permite discriminar precocemente os tumores com crescimento continuo daqueles que são regressivos. A taxa de crescimento tumoral é um parâmetro útil para a avaliação dos animais experimentais, particularmente no período que precede a regressão dos tumores