Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Childhood cancer has often been considered as a problem mainly affecting industrialized countries. In reality more than half of cases occur in developing countries where management and diagnosis are major issues. This retrospective study includes 130 children (0.3% of admissions) between the ages of 0 and 15 years hospitalized for malignant disease at the Principal Hospital in Dakar, Senegal between January 1, 1990 and December 31, 2000. Mean age was 97 months and M/F sex ratio was 1.2. Mean delay for admission was 3 months. The five most frequent cancers, accounting for 75% of cases, were leukemia (n = 28), lymphoma (n = 21), nephroblastoma (n = 21), retinoblastoma (n = 16) and osteochondrosarcoma (n = 10). Treatment was completed in 18% of cases. Half of patient were lost from follow-up. The cure rate was 10% overall and 50% for patients receiving complete treatment. The highest cure rate was achieved for nephroblastoma, i.e., 58% of cases treated. Management of childhood cancer in Africa is confronted with numerous problems, namely, paucity of specialized staff, absence of expert centers, shortage of anticancer drugs, lack of financial resources, and delay in treatment. These factors associated with frequent malnutrition and recurrent infectious diseases, greatly lower cure rates in comparison with industrialized countries.
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PMID:[Epidemiology and prognosis of childhood cancers in Dakar, Senegal]. 1476 9

The ionizing radiation dose-response relationships for internally deposited radionuclides are examined using data from humans involving Ra and laboratory animal studies involving alpha-emitters Ra, Ra, Ra, Th, Pu, Pu, and Am and beta-emitters Y, Sr, Y, and Ce. Intake routes included ingestion, inhalation, and injection. The lifetime effects are best described by three-dimensional average-dose-rate/time/response surfaces that compete with other causes of death during an individual's lifetime. Using maximum likelihood survival regression methods, the characteristic logarithmic slope for cancer induction was found to be about negative one-third for alpha-emitters or about negative two-thirds for beta-emitters. At the higher average dose-rates the principal deleterious effects were those associated with radiation-induced injury while at intermediate average dose-rates radiation-induced cancer predominates. The relative biological effectiveness for cancer induction of high linear energy transfer alpha radiation with respect to low linear energy transfer beta radiation is a strong function of dose-rate. As average dose-rate decreases, the effectiveness of the beta irradiation drops off more rapidly than that of the alpha irradiation. The cumulative dose yielding a specific level of induced cancer risk is less at lower dose-rates than at higher dose-rates showing an apparent inverse dose-rate effect (up to a factor of about 10 for high linear energy transfer alpha radiation and a factor of about 2 for low linear energy transfer beta radiation). The cumulative radiation dose is neither an accurate nor an appropriate measure of cancer risk associated with protracted ionizing radiation exposure. Cancer risk associated with protracted ionizing radiation exposure is a non-linear function of lifetime average dose-rate to the affected tissues. At low average dose-rates the long latency time required for radiation-induced cancer may exceed the natural lifespan. This long latency results in a lifespan virtual threshold (cancer risk p < 0.001) for each internally deposited radionuclide. For young adult beagles, bone sarcoma induction from alpha-emitting radionuclides was unlikely for cumulative doses below about 1 Gy (20 Sv) delivered specifically to the sensitive tissues at bone surfaces in a manner associated with radionuclide relative potency from highest for Th, Pu, and Pu to lowest for Ra. Bone sarcoma induction from ingested Sr was unlikely for cumulative beta radiation doses below about 20 Gy (20 Sv), but beta irradiation of tissues adjacent to bone also induced leukemia and soft tissue carcinomas above 10 Gy (10 Sv). Inhaled radionuclides tended to be most potent in producing lung carcinoma when the radiation dose was most uniformly distributed in the lung. In young adult beagles lung carcinoma from inhaled alpha-emitting Pu in the dispersible nitrate form was unlikely for cumulative doses below about 0.5 Gy (10 Sv) and below higher cumulative doses for other forms of Pu and Pu depending on relative potency. Lung carcinoma from inhaled beta-emitting Y in relatively insoluble fused aluminosilicate particles was unlikely for cumulative doses below about 5 Gy (5 Sv) and below higher doses for inhaled particles with Y, Ce, or Sr in order of decreasing potency.
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PMID:Concerning the health effects of internally deposited radionuclides. 2014 92