RESUMO
Mature trees scattered throughout agricultural landscapes are critical habitat for some biota and provide a range of ecosystem services. These trees are declining in intensively managed agricultural landscapes globally. We developed a simulation model to predict the rates at which these trees are declining, identified the key variables that can be manipulated to mitigate this decline, and compared alternative management proposals. We used the initial numbers of trees in the stand, the predicted ages of these trees, their rate of growth, the number of recruits established, the frequency of recruitment, and the rate of tree mortality to simulate the dynamics of scattered trees in agricultural landscapes. We applied this simulation model to case studies from Spain, United States, Australia, and Costa Rica. We predicted that mature trees would be lost from these landscapes in 90-180 years under current management. Existing management recommendations for these landscapes--which focus on increasing recruitment--would not reverse this trend. The loss of scattered mature trees was most sensitive to tree mortality, stand age, number of recruits, and frequency of recruitment. We predicted that perpetuating mature trees in agricultural landscapes at or above existing densities requires a strategy that keeps mortality among established trees below around 0.5% per year, recruits new trees at a rate that is higher than the number of existing trees, and recruits new trees at a frequency in years equivalent to around 15% of the maximum life expectancy of trees. Numbers of mature trees in landscapes represented by the case studies will decline before they increase, even if strategies of this type are implemented immediately. This decline will be greater if a management response is delayed.
Assuntos
Agricultura , Conservação dos Recursos Naturais/métodos , Ecossistema , Modelos Teóricos , Árvores/crescimento & desenvolvimento , Austrália , Simulação por Computador , Costa Rica , Dinâmica Populacional , Espanha , Estados UnidosRESUMO
OBJECTIVE: To determine the safety and immunogenicity of varicella vaccine in children with human immunodeficiency virus (HIV) infection. Children (n = 41) who were mildly affected by HIV (Centers for Disease Control and Prevention stage N1 or A1) and had no history or serum antibody indicative of prior varicella infection were immunized with two doses of live attenuated varicella vaccine. RESULTS: A minority of the vaccine recipients had mild local or systemic reactions. Vaccination had no effect on the clinical stage of HIV or the HIV RNA plasma load. CD4 cell percentage and CD4 cell count were marginally decreased at week 4 after the first vaccination; this effect was no longer present at week 8 after vaccination. Two months after the second dose of vaccine, 60% of vaccine recipients had anti-varicella antibody in their serum, and 83% had a positive lymphocyte proliferation assay response to varicella antigen. CONCLUSION: On the basis of its safety and immunogenicity, varicella vaccine should be considered in the childhood vaccines given to mildly affected HIV-infected children.
Assuntos
Anticorpos Antivirais/sangue , Vacina contra Varicela/efeitos adversos , Varicela/imunologia , Infecções por HIV/imunologia , Contagem de Linfócito CD4 , Vacina contra Varicela/imunologia , Criança , Pré-Escolar , Humanos , Lactente , Estudos Multicêntricos como Assunto , Carga ViralRESUMO
OBJECTIVE: The objective of this study was to determine the cause of purpura fulminans, disseminated intravascular coagulation, or thrombosis in seven children with varicella. All children were found to have a lupus anticoagulant and acquired protein S deficiency. Thrombosis in five children was associated with presumed or documented infection with streptococcus. STUDY DESIGN: Coagulation tests included determinations of the activated partial thromboplastin time, the prothrombin time, the dilute Russell viper venom time, the prothrombin F 1 + 2 fragment, the C4b-binding protein (C4b), total and free protein S antigen, and clotting activities of factors II, V, VII, and X and of protein C and protein S. Autoantibodies to phospholipids, cardiolipin, and protein S were determined in enzyme-linked immunosorbent assays. RESULTS: All children had a lupus anticoagulant and acquired protein S deficiency. Thrombosis in five children was associated with presumed or documented infection with streptococcus. All children transiently expressed free protein S deficiency, elevated levels of IgG, IgM, or both binding to protein S, the lupus anticoagulant, and increased concentration of the F 1+2 fragment. Four children also had antiphospholipid or anticardiolipin antibodies. In one child a purified IgG fraction cross-reacted with both protein S and a specific varicella antigen. CONCLUSIONS: A subset of children with varicella infection, some of whom are coinfected with streptococcus, are prone to development of a lupus anticoagulant and an autoantibody to protein S, which results in acquired free protein S deficiency. Such children are at risk of having life-threatening thrombotic events.
Assuntos
Varicela/complicações , Vasculite por IgA/etiologia , Inibidor de Coagulação do Lúpus/análise , Deficiência de Proteína S/etiologia , Trombose/etiologia , Anticorpos Antifosfolipídeos/análise , Testes de Coagulação Sanguínea , Estudos de Casos e Controles , Criança , Pré-Escolar , Coagulação Intravascular Disseminada/etiologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Lactente , Masculino , Fatores de Risco , Infecções Estreptocócicas/complicações , Streptococcus pyogenesRESUMO
A 10-day-old infant with stridor was found to have herpes simplex virus type 2 infection of the larynx. The infant's poor clinical response to both acyclovir and foscarnet prompted extensive clinical and virologic evaluations, which revealed acyclovir-resistant herpes simplex virus.
Assuntos
Aciclovir/uso terapêutico , Herpes Simples/tratamento farmacológico , Herpesvirus Humano 2/efeitos dos fármacos , Doenças da Laringe/tratamento farmacológico , Aciclovir/farmacologia , Resistência Microbiana a Medicamentos , Feminino , Foscarnet/uso terapêutico , Herpesvirus Humano 2/isolamento & purificação , Humanos , Recém-Nascido , Doenças da Laringe/microbiologiaRESUMO
Cytomegalovirus infection, a common complication in immunosuppressed graft recipients, bears an adverse impact on graft survival. Cytomegalovirus enhances the expression of the monotypic determinants of the class I major histocompatibility complex molecule by the endothelium, possibly rendering the endothelial cells more immunogenic and prone to attack by the allogeneic lymphocytes. In the present study, we focused on the effect of cytomegalovirus on the endothelial cell expression of different class I genes, on the relation between the extent of endothelial cell infection and the class I effect, and on the time course of the class I changes induced by the cytomegalovirus infection. Cytomegalovirus infection of primary cultures of human umbilical vein endothelial cells augmented the expression of the A2, A3, and B7 class I major histocompatibility complex genes when compared with uninfected cells. beta 2 microglobulin upregulation by the infected cells paralleled the changes in specific class I expression; this effect was significant only after 7 days after infection. Double immunocytochemical staining and fluorescence-activated cell sorter analysis revealed that the class I enhancement was uniform throughout the umbilical vein endothelial cell monolayer and not restricted to the cells that expressed cytomegalovirus early or late antigens. Ultraviolet-inactivated supernatants from infected umbilical vein endothelial cell did not increase class I expression on uninfected cells. In conclusion, cytomegalovirus might affect graft survival by amplifying the changes in class I expression beyond the sites of viral replication.
Assuntos
Infecções por Citomegalovirus/genética , Infecções por Citomegalovirus/imunologia , Citomegalovirus/genética , Citomegalovirus/imunologia , Endotélio Vascular/imunologia , Amplificação de Genes , Regulação Viral da Expressão Gênica , Antígenos de Histocompatibilidade Classe I/genética , Especificidade de Anticorpos , Antígenos Virais/análise , Células Cultivadas , Citomegalovirus/fisiologia , Citomegalovirus/efeitos da radiação , Citoplasma/ultraestrutura , Endotélio Vascular/microbiologia , Endotélio Vascular/ultraestrutura , Regulação Viral da Expressão Gênica/efeitos da radiação , Antígeno HLA-A2/análise , Antígeno HLA-A2/genética , Antígeno HLA-A3/análise , Antígeno HLA-A3/genética , Antígeno HLA-B7/análise , Antígeno HLA-B7/genética , Antígenos de Histocompatibilidade Classe I/análise , Humanos , Raios Ultravioleta , Regulação para Cima , Replicação Viral , Eliminação de Partículas Virais , Microglobulina beta-2/análise , Microglobulina beta-2/genéticaRESUMO
The objective of the present study was to estimate the prevalence of herpes simplex virus type 2 (HSV 2) antibodies in child bearing women of 2 Brazilian populations with different socioeconomic status and to determine the risk of neonatal HSV exposure by means of maternal cultures at the onset of labor. The study was conducted at 2 hospitals: A, serving very low income patients and B, serving middle socioeconomic class. 173 participants from group A and 127 from B answered a questionnaire which showed that the patients had similar ages (27.7 and 26.8 years, respectively) but differed with regard to socioeconomic status, age at first intercourse (18.6 vs 20.6 years), number of sex partners (1.5 vs 1.2) and previous sexually transmitted diseases (15 vs. 1.5). History of genital herpes was given by 11 of group A participants and by a similar number, 7, of patients from group B. In addition, 200 serum samples from population A and 455 from B were tested by ELISA for anti HSV antibodies and 92 and 86, respectively, were found to be positive. Sixty seropositive samples from group A and 90 from B were further analyzed by Western blot, which showed the presence of type 2 specific antibodies in 46 and 36, respectively, suggesting an overall HSV 2 prevalence of 42 in group A and 31 in B. Cervical specimens were obtained for culture from 299 asymptomatic patients of population A and 313 of B. HSV was isolated from one specimen in each group, indicating a 0.3 incidence of asymptomatic viral excretion in both populations.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Humanos , Feminino , Gravidez , Recém-Nascido , Adulto , Complicações Infecciosas na Gravidez/epidemiologia , Herpes Genital , Herpesvirus Humano 2 , Brasil , Herpes Genital , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Fatores SocioeconômicosRESUMO
The objective of the present study was to estimate the prevalence of herpes simplex virus type 2 (HSV 2) antibodies in child bearing women of 2 Brazilian populations with different socioeconomic status and to determine the risk of neonatal HSV exposure by means of maternal cultures at the onset of labor. The study was conducted at 2 hospitals: A, serving very low income patients and B, serving middle socioeconomic class. 173 participants from group A and 127 from B answered a questionnaire which showed that the patients had similar ages (27.7 and 26.8 years, respectively) but differed with regard to socioeconomic status, age at first intercourse (18.6 vs 20.6 years), number of sex partners (1.5 vs 1.2) and previous sexually transmitted diseases (15% vs. 1.5%). History of genital herpes was given by 11% of group A participants and by a similar number, 7%, of patients from group B. In addition, 200 serum samples from population A and 455 from B were tested by ELISA for anti HSV antibodies and 92% and 86%, respectively, were found to be positive. Sixty seropositive samples from group A and 90 from B were further analyzed by Western blot, which showed the presence of type 2 specific antibodies in 46% and 36%, respectively, suggesting an overall HSV 2 prevalence of 42% in group A and 31% in B. Cervical specimens were obtained for culture from 299 asymptomatic patients of population A and 313 of B. HSV was isolated from one specimen in each group, indicating a 0.3% incidence of asymptomatic viral excretion in both populations.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Herpes Genital/epidemiologia , Herpesvirus Humano 2/isolamento & purificação , Complicações Infecciosas na Gravidez/epidemiologia , Adulto , Brasil/epidemiologia , Feminino , Herpes Genital/sangue , Herpes Genital/transmissão , Humanos , Recém-Nascido , Gravidez , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Fatores SocioeconômicosRESUMO
Breast milk samples from three groups of Brazilian women were evaluated: G1, mothers delivering term babies of low birth weight (n = 16); G2, mothers delivering preterm babies of appropriate birth weight (n = 20); G3, mothers delivering term babies of appropriate birth weight (n = 30). Milk samples were obtained at 48 h and on the 7th, 15th, 30th and 60th days after delivery and they were analyzed for lysozyme and total IgA levels and for the presence of specific antibodies against Poliovirus types I, II, III, Rotavirus, Herpes simplex virus, Varicella zoster and Cytomegalovirus. The groups were not statistically different in relation to mother's age, parity, type of delivery or socio-economic levels. IgA levels were higher in both low-birth-weight groups (G1 & G2) compared to the control group (G3) throughout the study period. Lysozyme levels decreased up to the 15th day, increasing thereafter up to the 60th day in all groups. Specific antibodies were detected throughout the study period, with no differences among groups. We conclude that breast milk composition of mothers delivering low-birth-weight babies (G1 & G2) was similar despite the different gestational ages.
Assuntos
Imunoglobulina A/análise , Leite Humano/imunologia , Adolescente , Adulto , Anticorpos Antivirais/análise , Brasil , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Recém-Nascido Pequeno para a Idade Gestacional , Leite Humano/química , Muramidase/análise , Poliovirus/imunologia , Rotavirus/imunologiaRESUMO
PURPOSE: To determine how often and by what means an indentifiable pulmonary pathogen can be recognized in human immunodeficiency virus (HIV) infected patients with respiratory disorders in Brazil, which are the most frequently observed microorganisms and what impact specific therapy has on these agents. PATIENTS AND METHODS: Thirty-five HIV seropositive subjects with respiratory complaints were studied. All patients had a complete history, physical examination and blood counts. The pulmonary assessment included chest radiograms; sputum examination for bacterial and fungal pathogens; bronchoscopy with bronchoalveolar lavage and transbronchial biopsy. Patients with treatable complications received standard antimicrobial therapy. RESULTS: One or more microorganisms were found in 24 subjects and another 3 individuals showed nonspecific interstitial pneumonitis. The sputum examination identified the pulmonary pathogens in 7 cases. The bronchoalveolar lavage and the histopathologic examination were diagnostic in 14% and 83%, respectively, of the 28 individuals that were submitted to bronchoscopy. The most frequently identified microorganism was P. carinii (55%), followed by M. tuberculosis (41%) and cytomegalovirus (8%). The clinical, laboratory and radiographic findings failed to distinguish the specific pulmonary pathogens. Twenty-three individuals with P. carinii pneumonitis and/or tuberculosis received specific therapy; among the evaluable patients the therapeutic response rates were 79% for PCP and 100% for TB. CONCLUSIONS: We have determined that tuberculosis, P. carinii and cytomegalovirus pneumonitis are the most common respiratory opportunistic diseases in Brazilian patients infected with HIV. The histologic evaluation was crucial in order to identify the pulmonary pathogens. Tuberculosis in AIDS individuals displayed clinical and radiographic findings atypical for reactivation disease. However, most of the features observed in HIV infected patients had been previously described in infection of the normal host. Furthermore, the AIDS subjects showed a good therapeutic response to anti-tuberculous drugs.
PIP: The authors conducted complete histories, physical examinations, blood counts, chest radiograms, sputum examinations for bacterial and fungal pathogens, and bronchoscopy with bronchoalveolar lavage and transbronchial biopsy on 35 HIV-seropositive individuals with respiratory complaints in a study to determine how often and by what means an identifiable pulmonary pathogen can be recognized in HIV-infected patients with respiratory disorders in Brazil, which are the most frequently observed microorganisms, and what impact specific therapy has on the agents. One or more microorganisms were found in 24 subjects, while another three individuals showed nonspecific interstitial pneumonitis. Tuberculosis (TB) found in 41% of cases, P. carinii in 55%, and cytomegalovirus pneumonitis in 8% were the most common respiratory opportunistic diseases among the study subjects. Histologic evaluation was essential to identify the pulmonary pathogens, with clinical, laboratory, and radiographic findings failing to distinguish the specific pathogens. 23 individuals with P. carinii pneumonitis and/or TB received specific therapy; among the patients who could be evaluated, the therapeutic response rates were 79% for PCP and 100% for TB. TB in these individuals displayed clinical and radiographic findings atypical for reactivation disease. The authors note that most of the features observed in HIV-infected patients had been previously described in infection of the normal host.
Assuntos
Infecções por Citomegalovirus/etiologia , Soropositividade para HIV/complicações , Infecções Oportunistas/etiologia , Pneumonia por Pneumocystis/etiologia , Tuberculose Pulmonar/etiologia , Adulto , Brasil , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
From July 1985 to February 1987, of 46 consecutive children with cancer (26 male, 20 female; median age, 4 years) with no prior history of chickenpox, the initial 30 patients were randomized either to receive or not to receive live attenuated varicella vaccine (LAVV) before chemotherapy was started and the remaining 16 patients were all immunized without randomization. Before immunization, Varicella zoster (VZ) antibodies were detected by immunofluorescence and ELISA in 11 (34%) of 32 vaccinated children and two (14%) of 14 controls, indicating previous infection. A booster effect was evident in 70% of them and no side effects were noted. Ten (28%) of 32 vaccinees were excluded from the analysis because of early death due to cancer (1-4 weeks). Seroconversion was demonstrated in ten (77%) of 13 vaccinees, with high antibody titres. Only three of them lost their antibodies 2 years after immunization, as disclosed by serological follow-up. Eight out of 13 vaccinees had household contacts with VZ and none became infected. Zoster immunoglobulin (ZIG) was never given. Among controls, seven out of 14 were exposed to VZ and four (57%) became infected. Mild side effects were observed in four (12.5%) out of 32 vaccinees (three with papulovesicular rash, 6-30 lesions, and one with a 3-day intermittent fever). Local reactions, zoster and spreading of vaccinal virus did not occur. LAVV proved to be safe and effective when administered before starting chemotherapy to children with cancer and no history of varicella.