Polycyclic aromatic hydrocarbons in carcinogenesis.
(65/40131)
A symposium on "Polycyclic Aromatic Hydrocarbons (PAHs) in Carcinogenesis" was presented at the third International Congress of Pathophysiology held in Lathi, Finland, 28 June-3 July 1998. The congress was also sponsored by the International Union of Biological Sciences and the International Society of Free Radical Research. Institutional support for the symposium included the Electric Power Research Institute, National Center for Toxicological Research, and EPA/National Health and Environmental Effects Research Laboratory and the Office of Solid Waste and Emergency Response. The symposium focused on the sources, carcinogenicity, genotoxicity, and risk assessment of individual and mixtures of PAHs that are found in solid wastes, Superfund sites, and other hazardous waste sites. Based on the occurrence of PAHs at numerous Superfund sites and the significant data gaps on the toxic potential of certain PAHs, the information developed during this symposium would be of value in assessing health risks of these chemicals at Superfund and other hazardous waste sites. (+info)
Prognostic significance of bone marrow biopsy in essential thrombocythemia.
(66/40131)
BACKGROUND AND OBJECTIVE: The diagnostic and prognostic value of bone marrow biopsy (BMB) has been widely investigated in patients with chronic myeloproliferative disorders (CMPD). The present study is based on a review of the results of routine BMBs taken from 93 essential thrombocythemia (ET) patients at the time of diagnosis. DESIGN AND METHODS: The common BMB histologic parameters and clinico-hematologic variables were considered for diagnostic and prognostic purposes. Clinico-pathologic correlations were looked for univariately. Moreover, the diagnostic significance of the histologic findings was tested by means of cluster analysis. Overall survival and event-free survival were considered as prognostic endpoints. RESULTS: There were no correlations between the clinic and pathologic findings, and none of the histologic and clinical parameters was predictive of survival or the occurrence of major clinical events. Cluster analysis of the BMB findings revealed two distinct morphologic patterns: one was clearly myeloproliferative; the other had somewhat dysplastic features. The event-free and overall survival rates in the latter group were significantly worse (p = 0.0377 and p = 0.0162 respectively), with major ischemic events accounting for most of the difference in event-free survival. INTERPRETATION AND CONCLUSIONS: These results have no clearcut counterpart in the literature, but we feel that dysplastic BMB findings could be included in the definition of ET prognostic scores in order to allow therapeutic strategies to be adapted to the level of risk. (+info)
BACKGROUND AND OBJECTIVE: In children it is very important to optimize PBPC harvesting and to reduce the number of leukaphereses per patient. The value of pre-apheresis peripheral blood CD34+ cell concentration as a predictor of PBPC yield was studied in 23 pediatric patients with hematologic and non-hematologic malignancies in order to optimize duration of PBPC collection. DESIGN AND METHODS: The patients underwent 25 stem-cell mobilization episodes with G-CSF alone and 40 large-volume leukapheresis procedures. Peripheral blood and harvested CD34+ cell concentrations were analyzed by means of flow cytometry. RESULTS: Using linear regression analysis, a highly significant correlation was found between the peripheral blood CD34+ cell count and the CD34+ cells/kg patient body weight collected on the apheresis day (r = 0.826, p = 0.0001). The results indicate that at least 1 x 10(6)/kg CD34+ cells can be harvested during one leukapheresis procedure in all patients if the pre-apheresis blood CD34+ cell count is > or = 30/microL and a CD34+ cell target of > or = 5 x 10(6)/kg is achieved in at least 80% of patients if this value is > or = 50 CD34+ cells/microL processing a median blood volume of 438.7 mL/kg (range, 207-560) over a median time of 232.5 minutes (range, 182-376). INTERPRETATION AND CONCLUSIONS: Our results suggest that the number of CD34+ cells harvested in a single large-volume leukapheresis can be predicted from the measurement of peripheral blood CD34+ cell concentration on the collection day. (+info)
Infection of apheresis cells by parvovirus B19.
(68/40131)
Parvovirus B19 is the only member of the Parvoviridae family known to cause disease in humans. Owing to the high level of cell tropism the virus can only replicate in proliferating and differentiating erythroid precursor cells, which are present in human bone marrow and foetal liver. As human bone marrow is very difficult to obtain, an alternative in vitro system for the propagation of B19 virus has been developed, based on the application of mobilized haemapoietic progenitor (apheresis) cells. These cells are routinely harvested from cancer patients after treatment with recombinant human granulocyte/macrophage colony-stimulating factor. Replication of parvovirus B19 in vitro is possible in these cells after stimulation with erythropoietin. Therefore, this system is an easily, accessible alternative to the use of human bone marrow in parvovirus B19 infection assays. (+info)
Low mortality rates in industrial cohort studies due to selection for work and survival in the industry.
(69/40131)
Occupational groups are often described as being relatively healthy because their mortality rates are lower than those of the national average. Although correct this confuses the issue for those who are interested in assessing the effects of exposure to a particular chemical. In a further analysis of data collected in a study of all men ever exposed to vinyl chloride monomer in the manufacture of polyvinyl chloride in Great Britain, three factors have been shown to contribute to the low mortality rates that were observed. The three factors: the selection of a healthy population for employment, the survival in the industry of the healthier men, and the length of time that this population has been pursued, have been quantified. The mortality experience within five years of entering this industry was shown to be as low as 37% of that expected; for circulatory disease and respiratory disease it was as low as 21%. There was a progressive increase in standardized mortality ratio with the length of time since entry so that the effect had almost disappeared 15 years after entry. To avoid confounding the selection effect with the survival effect the latter was measured by separating men who survived 15 years after entering the industry according to whether or not they were still in the industry after this period. Those who had left experienced an overall standardized mortality ratio some 50% higher than those still in the industry. This effect, although consistent in the age groups between 25 and 74 years and for all cause groups studied, was greatest in those aged between 25 and 44 years and for lung cancer and respiratory disease. (+info)
p53-oriented cancer therapies: current progress.
(70/40131)
Nearly twenty years after the initial discovery of p53, we are now in an ideal position to exploit our vast knowledge of p53 biology in the creation of novel cancer therapies. Disruption of p53 function through mutation, or other means, occurs very frequently in human cancer. Loss of p53 function has been linked with unfavourable prognosis in a large number of tumour types, as indicated by more aggressive tumours, early metastasis and decreased survival rates. Many different avenues of research have converged upon p53 to highlight this protein as being one of the foremost cellular responders to stress, in particular to DNA damage. Huge advances have been made in understanding the complex role p53 plays in the regulation of apoptosis and cell cycle arrest. This review is not meant to be a comprehensive description of p53 biology, but rather serves to highlight current progress in the development of p53-oriented cancer therapies. These may be categorised into three basic strategies: gene replacement therapy using wild-type p53, restoration of p53 function by other means and, finally, targeting of the p53 dysfunction itself. Rapid progress is expected to be made regarding the identification of conventional pharmaceutical agents which either work in a p53-independent manner or act preferentially in p53 defective cells. Gene replacement therapy with wild-type p53 also holds considerable potential for obtaining clinically relevant results quickly. The other forms of cancer therapies based around p53 are much further behind in the developmental process, but may prove to more efficacious in the long run, especially in terms of specificity. As with many other fields, the innovation of successful p53-oriented cancer therapies is only limited by our understanding of p53 biology and the creative use of such knowledge. (+info)
Use of resources and costs of palliative care with parenteral fluids and analgesics in the home setting for patients with end-stage cancer.
(71/40131)
BACKGROUND: In 1992 a home care technology project was started in which infusion therapy in the home setting was made available for patients with end-stage cancer. Beside aspects of feasibility and quality of life the resource utilization and costs of this transition was studied. PATIENTS AND METHODS: We conducted a cost evaluation study, to determine the actual cost of managing patients with endstage cancer who require parenteral administration of fluid or analgesics in the home setting. A total of 128 patients were prospectively followed, with a detailed analysis of some aspects in a sample of 24 patients. RESULTS: The cost for each patient was found to be between $250.00 and $300.00 per day, half of which are for hospital charges, even with this active home care technology program. One-third of the costs can be attributed to primary health care activities, in particular those of the district nurses. A hypothetical control group (n = 25) was constructed based on current practice and chart review. Patients in this group would have cost around $750.00 per day. With a median treatment period of 16 days this means a saving of $8000.00 per patient. CONCLUSION: Our data suggest that significant savings can be obtained by implementing programs transferring palliative care technology to the home setting. (+info)
A phase I study of docetaxel and 5-fluorouracil in patients with advanced solid malignancies.
(72/40131)
PURPOSE: This study was undertaken to evaluate the feasibility of administering docetaxel (Taxotere; Rhone-Poulenc-Rorer) as a one-hour intravenous (i.v.) infusion on day 1 combined with 5-fluorouracil (5-FU) as a bolus i.v. injection for five (days 1-5) or three (days 1-3) consecutive days every four weeks. PATIENTS AND METHODS: Thirty-seven patients with advanced solid malignancies were treated with 115 total courses involving seven dose levels of the two regimens of docetaxel and 5-FU (docetaxel/5-FU [mg/m2]/mg/m2/d]). In an effort to reduce fluid retention and hypersensitivity phenomena related to docetaxel, patients received premedication with dexamethasone 8 mg orally twice daily for three consecutive days beginning 24 hours before treatment. RESULTS: Severe (grade 4) neutropenia lasting longer than seven days with or without fever and/or severe mucositis, precluded further dose escalation above docetaxel 60 mg/m2 on day 1 and 5-FU 300 mg/m2/day administered on days 1-5 every four weeks. The rates of these toxic effects were also unacceptably high above docetaxel 60 mg/m2 on day 1 and 5-FU 300 mg/m2/day administered on days 1-3 every four weeks. Nine patients experienced various manifestations of fluid-retention that were potentially related to study drugs. However, neither treatment delay nor discontinuation of treatment was required. Nausea, vomiting, diarrhea, and fatigue, were mild to modest in severity and occurred infrequently (< 10% of courses). Two patients with metastatic breast cancer experienced complete responses and a partial response occurred in a patient with metastatic non-small-cell lung cancer. CONCLUSION: Based on the results of this study, the regimen of docetaxel 60 mg/m2 on day 1 followed by 5-FU 300 mg/m2/d i.v. for three or five days every four weeks is well tolerated and these doses are recommended for further evaluations. The feasibility of administering docetaxel 60 mg/m2 followed by 5-FU 300 mg/m2 for three or five days every four weeks and the preliminary antitumor activity noted indicate that further disease-directed studies of docetaxel and 5-FU are warranted in patients with relevant solid malignancies. (+info)