13 research outputs found
Potentiation of the therapeutic activity of cyclophosphamide by an original N-acyldehydroalanine.
No full textResearch work is currently in progress with the aim of improving the efficacy and/or reducing the toxicity of cancer treatments. The present communication reports on the effect of an original molecule, N-(ortho-methoxyphenylacetyl)dehydroalanine, known as AD20. In a protocol in which L1210 leukaemic cells, AD20 and cyclophosphamide were injected i.p. into BDF1 mice, the association CP-AD20 was more active than CP alone at therapeutic or subtherapeutic doses of CP. If the doses of CP were higher than its optimum therapeutic dose, the association CP-AD20 was more toxic than CP alone. The positive effect of AD20 was also observed when AD20 was given i.v. or when the leukaemic cells were implanted s.c., CP always being injected i.p. Taking into account its low toxicity, AD20 exhibits interesting properties that could support its development as an adjuvant for cancer chemotherapy
Maternal Virus Load during Pregnancy and Mother-to-Child Transmission of Human Immunodeficiency Virus Type 1: The French Perinatal Cohort Studies
No full textDoes management in tropical forests in the Eastern Amazon influence forest species\' long-term recovery and spatial behavior?
No full textEste estudo objetiva avaliar a influência do manejo florestal na recuperação dos estoques de biomassa e volume e no comportamento espacial das espécies Caryocar villosum (Aubl.) Pers., Copaifera duckei Dwyer, Hymenaea courbaril L. e Manilkara elata (Allemão ex Miq.) Monach. após 24 anos. A pesquisa foi realizada em uma área privada de floresta tropical localizada no município de Paragominas, PA, Brasil. Em 1993 foi realizada a exploração convencional em 75 ha e a manejo com impacto reduzido em 105 ha. Em cada área explorada foram alocadas parcelas de 24,5 ha (350 m x 700 m) para fins de monitoramento. Além das duas áreas exploradas, também foi alocada uma parcela de 24,5 ha em uma área controle, sem exploração. As três parcelas foram monitoradas por 24 anos através do inventário de todos os indivíduos com DAP ≥ 10 cm. Para fins de comparação, foram utilizados os bancos de dados dos anos de 1993 (antes da exploração), 1994 (1 ano após exploração) e 2017 (24 anos após a exploração). Foram feitas análises para estimar a biomassa e volume de cada espécie com auxílio do software R 4.0.2. O padrão de distribuição espacial das quatro espécies em cada tratamento foi determinado com o uso da função K de Ripley univariada e para análise de distribuição da densidade utilizou-se a ferramenta Kernel Density, com auxílio do Sistema de Informação Geográficas ArcGIS® 10.8. Como resultados, foi constatado que o manejo com a adoção de estratégias de impacto reduzido promoveu uma recuperação mais eficaz dos estoques de biomassa e volume das quatro espécies florestais quando comparada a exploração convencional, porém não o suficiente para recuperação total dos estoques iniciais. As quatro espécies estudadas apresentaram distribuição espacial aleatória e o comportamento espacial da espécie Hymenaea courbaril foi influenciado pelas mudanças ocorridas após a exploração convencional. Os resultados apresentados neste estudo contribuem para o conhecimento do comportamento ecológico de algumas espécies florestais de valor comercial, o que é de extrema importância para que propostas de mudanças no manejo em florestas tropicais sejam discutidas e implementadas.This study aims to evaluate the influence of forest management in the recovery of biomass and volume stocks and the spatial behavior of Carycar villosum species (Aubl.), Copaifera duckei Dwyer, Hymenaea courbaril L. and Manilkara elata (Allemon ex Miq.) Monach. after 24 years. The research was held in a private area of tropical forest located in the municipality of Paragominas, PA, Brazil. In 1993 the conventional exploitation was carried out in 75 ha, and the management with a reduced impact in 105 ha. In each operated area, installments of 24.5 ha (350 m x 700 m) were allocated for monitoring purposes. In addition to the two areas explored, a portion of 24.5 ha was also distributed in a control area without exploitation. The three installments were monitored for 24 years through the inventory of all individuals with DAP ≥ 10 cm. For comparison purposes, the 1993 years databases (before exploitation) were used, 1994 (1 year after exploitation) and 2017 (24 years after exploitation). Analyzes were made to estimate the biomass and volume of each species with the aid of R 4.0.2. The spatial distribution pattern of the fourth species in each treatment was determined using the univariate Ripley function. For density distribution analysis, the \"kernel density\" tool was used with the aid of the ARCGIS®10.8 geographic information system. As a result, it was found that the management with the adoption of reduced impact strategies promoted a more effective recovery of biomass stocks and volume of four forest species when compared to conventional exploitation, but not enough for a total recovery of initial inventories. The four species studied presented random spatial distribution, and the spatial behavior of the Hymenaea courbaril species was influenced by the changes occurring after conventional exploitation. The results presented in this study contribute to the knowledge of the ecological behavior of some forest species of commercial value, which is extremely important so that proposals for changes in management in tropical forests are discussed and implemented
Duration of ruptured membranes and vertical transmission of HIV-1: A meta-analysis from 15 prospective cohort studies
No full textObjective: To test the a priori hypothesis that longer duration of ruptured membranes is associated with increased risk of vertical transmission of HIV. Design: The relationship between duration of ruptured membranes and vertical transmission of HIV was evaluated in an individual patient data meta-analysis. Methods: Eligible studies were prospective cohort studies including at least 100 mother-child pairs, from regions where HIV-infected women are counselled not to breastfeed. Analyses were restricted to vaginal deliveries and non-elective Cesarean sections; elective Cesarean section deliveries (those performed before onset of labour and before rupture of membranes) were excluded. Results: The primary analysis included 4721 deliveries with duration of ruptured membranes ≤ 24 h. After adjusting for other factors known to be associated with vertical transmission using logistic regression analysis to assess the strength of the relationship, the risk of vertical HIV transmission increased approximately 2% with an increase of 1 h in the duration of ruptured membranes [adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.04; for each 1 h increment]. There were no significant interactions of duration of ruptured membranes with study cohort or with any of the covariates, except maternal AIDS. Among women diagnosed with AIDS, the estimated probability of transmission increased from 8% to 31% with duration of ruptured membranes of 2 h and 24 h respectively (P < 0.01). Conclusions: These results support the importance of duration of ruptured membranes as a risk factor for vertical transmission of HIV and suggest that a diagnosis of AIDS in the mother at the time of delivery may potentiate the effect of duration of ruptured membranes. © 2001 Lippincott Williams & Wilkins
The Mode Of Delivery And The Risk Of Vertical Transmission Of Human Immunodeficiency Virus Type 1. A Meta-Analysis Of 15 Prospective Cohort Studies
No full textBackground To evaluate the relation between elective cesarean section and vertical transmission of human immunodeficiency virus type 1 (HIV-1), we performed a meta-analysis using data on individual patients from 15 prospective cohort studies. Methods North American and European studies of at least 100 mother-child pairs were included in the meta-analysis. Uniform definitions of modes of delivery were used. Elective cesarean sections were defined as those performed before onset of labor and rupture of membranes. Multivariate logistic-regression analysis was used to adjust for other factors known to be associated with vertical transmission. Results The primary analysis included data on 8533 mother-child pairs. After adjustment for receipt of antiretroviral therapy, maternal stage of disease, and infant birth weight, the likelihood of vertical transmission of HIV-1 was decreased by approximately 50 percent with elective cesarean section, as compared with other modes of delivery (adjusted odds ratio, 0.43; 95 percent confidence interval, 0.33 to 0.56). The results were similar when the study population was limited to those with rupture of membranes shortly before delivery. The likelihood of transmission was reduced by approximately 87 percent with both elective cesarean section and receipt of antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, as compared with other modes of delivery and the absence of therapy (adjusted odds ratio, 0.13; 95 percent confidence interval, 0.09 to 0.19), Among mother-child pairs receiving antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, rates of vertical transmission were 2.0 percent among the 196 mothers who underwent elective cesarean section and 7.3 percent among the 1255 mothers with other modes of delivery. Conclusions The results of this meta-analysis suggest that elective cesarean section reduces the risk of transmission of HIV-1 from mother to child independently of the effects of treatment with zidovudine. (N Engl J Med 1999;340:977-87.) (C)1999, Massachusetts Medical Society
The use of viral culture and p24 antigen testing to diagnose human immunodeficiency virus infection in neonates
No full textThe mode of delivery and the risk of vertical transmission of human immunodeficiency virus type 1--a meta-analysis of 15 prospective cohort studies. The International Perinatal HIV Group.
No full textTo evaluate the relation between elective cesarean section and vertical transmission of human immunodeficiency virus type 1 (HIV-1), we performed a meta-analysis using data on individual patients from 15 prospective cohort studies.
North American and European studies of at least 100 mother-child pairs were included in the meta-analysis. Uniform definitions of modes of delivery were used. Elective cesarean sections were defined as those performed before onset of labor and rupture of membranes. Multivariate logistic-regression analysis was used to adjust for other factors known to be associated with vertical transmission.
The primary analysis included data on 8533 mother-child pairs. After adjustment for receipt of antiretroviral therapy, maternal stage of disease, and infant birth weight, the likelihood of vertical transmission of HIV-1 was decreased by approximately 50 percent with elective cesarean section, as compared with other modes of delivery (adjusted odds ratio, 0.43; 95 percent confidence interval, 0.33 to 0.56). The results were similar when the study population was limited to those with rupture of membranes shortly before delivery. The likelihood of transmission was reduced by approximately 87 percent with both elective cesarean section and receipt of antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, as compared with other modes of delivery and the absence of therapy (adjusted odds ratio, 0.13; 95 percent confidence interval, 0.09 to 0.19). Among mother-child pairs receiving antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, rates of vertical transmission were 2.0 percent among the 196 mothers who underwent elective cesarean section and 7.3 percent among the 1255 mothers with other modes of delivery.
The results of this meta-analysis suggest that elective cesarean section reduces the risk of transmission of HIV-1 from mother to child independently of the effects of treatment with zidovudine
