RESUMEN
Protected areas (PAs) are a commonly used strategy to confront forest conversion and biodiversity loss. Although determining drivers of forest loss is central to conservation success, understanding of them is limited by conventional modeling assumptions. We used random forest regression to evaluate potential drivers of deforestation in PAs in Mexico, while accounting for nonlinear relationships and higher order interactions underlying deforestation processes. Socioeconomic drivers (e.g., road density, human population density) and underlying biophysical conditions (e.g., precipitation, distance to water, elevation, slope) were stronger predictors of forest loss than PA characteristics, such as age, type, and management effectiveness. Within PA characteristics, variables reflecting collaborative and equitable management and PA size were the strongest predictors of forest loss, albeit with less explanatory power than socioeconomic and biophysical variables. In contrast to previously used methods, which typically have been based on the assumption of linear relationships, we found that the associations between most predictors and forest loss are nonlinear. Our results can inform decisions on the allocation of PA resources by strengthening management in PAs with the highest risk of deforestation and help preemptively protect key biodiversity areas that may be vulnerable to deforestation in the future.
Identificación de los factores biofísicos y socioeconómicos que impulsan la pérdida de bosques en las áreas protegidas Resumen Las áreas protegidas son una estrategia de uso común para hacer frente a la conversión forestal y la pérdida de biodiversidad. Aunque determinar los factores que impulsan la pérdida de bosques es fundamental para el éxito de la conservación, su comprensión se ve limitada por los supuestos de modelación convencionales. Utilizamos la regresión de bosques aleatorios para evaluar los posibles impulsores de la deforestación en las áreas protegidas de México, considerando las relaciones no lineales y las interacciones de orden superior que subyacen a los procesos de deforestación. Los impulsores socioeconómicos (densidad de carreteras, densidad de población humana) y las condiciones biofísicas subyacentes (precipitaciones, distancia al agua, elevación, pendiente) fueron predictores más fuertes de la pérdida de bosques que las características de las áreas protegidas, como la edad, el tipo y la efectividad de la gestión. Dentro de las características de las áreas protegidas, las variables que reflejan una gestión colaborativa y equitativa y el tamaño del área protegida fueron los predictores más potentes de la pérdida de bosques, aunque con menor poder explicativo que las variables socioeconómicas y biofísicas. A diferencia de los métodos utilizados anteriormente, que suelen basarse en el supuesto de relaciones lineales, observamos que las asociaciones entre la mayoría de los predictores y la pérdida de bosques no son lineales. Nuestros resultados pueden servir de base para la toma de decisiones sobre la asignación de los recursos para las áreas protegidas, reforzando la gestión en las zonas protegidas con mayor riesgo de deforestación y ayudando a proteger de forma preventiva zonas clave para la biodiversidad que pueden ser vulnerables a la deforestación en el futuro.
Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales , Humanos , Conservación de los Recursos Naturales/métodos , México , Densidad de Población , Factores SocioeconómicosRESUMEN
Payments for Ecosystem Services (PES) are now a prominent policy instrument for conserving tropical forests. PES are voluntary, direct, and contractual: an ES buyer pays an ES steward for adopting conservation practices for a fixed term. A defining feature of PES is its 'quid pro quo' conditionality, e.g. stewards are paid only if they deliver contracted conservation outcomes. Most studies on PES effectiveness focus on the steward's compliance with contract conditions. By contrast, the buyer's compliance has received scant attention despite the fact that PES programs across the globe have delayed payments, suspended re-enrollment, or shut down altogether. 'Use-restricting' PES depend on the continued flow of funding to pay for conservation; however, institutional, political, and economic factors can disrupt or terminate PES funding. What happens when the PES money unexpectedly runs out? Do stewards continue to conserve or revert to their former practices? We use mixed methods to study equity concerns and forest outcomes of an unexpected, two-year interruption in conservation payments to 63 private landowners residing in Ecuador's Amazon and enrolled in the Socio Bosque program, compared to similar landowners who did not enroll. Using quasi-experimental methods, we found that during the payment suspension period enrolled properties did not maintain their conservation outcomes where deforestation pressures were high (e.g. close to roads). Where deforestation pressures were low, enrolled properties continued to conserve more, on average, than similar properties not enrolled. Findings from 40 interviews and 26 focus groups conducted before, during, and after the payment suspension exposed profound landowner uncertainty regarding their contract rights. Poor official communication and imbalanced PES contract terms reinforced power inequalities between the state and rural ES stewards. Our work highlights the need to plan for financial volatility and to protect participants' rights in PES contract design.
RESUMEN
PURPOSE: Children's Oncology Group (COG) AALL0331 tested whether intensified postinduction therapy that improves survival in children with high-risk B-cell acute lymphoblastic leukemia (ALL) would also improve outcomes for those with standard-risk (SR) ALL. PATIENTS AND METHODS: AALL0331 enrolled 5,377 patients between 2005 and 2010. All patients received a 3-drug induction with dexamethasone, vincristine, and pegaspargase (PEG) and were then classified as SR low, SR average, or SR high. Patients with SR-average disease were randomly assigned to receive either standard 4-week consolidation (SC) or 8-week intensified augmented Berlin-Frankfurt-Münster (BFM) consolidation (IC). Those with SR-high disease were nonrandomly assigned to the full COG-augmented BFM regimen, including 2 interim maintenance and delayed intensification phases. RESULTS: The 6-year event-free survival (EFS) rate for all patients enrolled in AALL0331 was 88.96% ± 0.46%, and overall survival (OS) was 95.54% ± 0.31%. For patients with SR-average disease, the 6-year continuous complete remission (CCR) and OS rates for SC versus IC were 87.8% ± 1.3% versus 89.1% ± 1.2% (P = .52) and 95.8% ± 0.8% versus 95.2% ± 0.8% (P = 1.0), respectively. Those with SR-average disease with end-induction minimal residual disease (MRD) of 0.01% to < 0.1% had an inferior outcome compared with those with lower MRD and no improvement with IC (6-year CCR: SC, 77.5% ± 4.8%; IC, 77.1% ± 4.8%; P = .71). At 6 years, the CCR and OS rates among 635 nonrandomly treated patients with SR-high disease were 85.55% ± 1.49% and 92.97% ± 1.08%, respectively. CONCLUSION: The 6-year OS rate for > 5,000 children with SR ALL enrolled in AALL0331 exceeded 95%. The addition of IC to treatment for patients with SR-average disease did not improve CCR or OS, even in patients with higher MRD, in whom it might have been predicted to provide more value. The EFS and OS rates are excellent for this group of patients with SR ALL, with particularly good outcomes for those with SR-high disease.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Quimioterapia de Consolidación/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Niño , Preescolar , Supervivencia sin Enfermedad , Femenino , Humanos , Quimioterapia de Inducción/métodos , Lactante , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Resultado del TratamientoRESUMEN
Pediatric Burkitt lymphoma has historically been treated with intensive methotrexate-based chemotherapy, which improves patient survival while causing severe toxicities. Young patients typically have better outcomes with intensive therapies, while adults and immunocompromised patients have higher toxicities and worse outcomes. Newer treatment regimens, including etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab (EPOCH-R), show promise for these patients. However, few studies exist to demonstrate efficacy and improved toxicity profile with EPOCH-R. We present 2 cases: a 25-year-old male with Down syndrome and an 18-year-old male with Burkitt lymphoma and significant renal injury who were successfully treated with EPOCH-R with minimal toxicities.
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Lesión Renal Aguda/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Linfoma de Burkitt/tratamiento farmacológico , Síndrome de Down/tratamiento farmacológico , Lesión Renal Aguda/complicaciones , Lesión Renal Aguda/patología , Adolescente , Adulto , Linfoma de Burkitt/complicaciones , Linfoma de Burkitt/patología , Ciclofosfamida/administración & dosificación , Síndrome de Down/complicaciones , Síndrome de Down/patología , Doxorrubicina/administración & dosificación , Etopósido/administración & dosificación , Humanos , Masculino , Prednisona/administración & dosificación , Pronóstico , Rituximab/administración & dosificación , Vincristina/administración & dosificaciónRESUMEN
Protected areas (PAs) are a prominent approach to maintaining and enhancing biodiversity and ecosystem services. A critical question for safeguarding these resources is how PA governance processes and management structures influence their effectiveness. We conduct an impact evaluation of 12 PAs in three Central American countries to assess how processes in management restrictions, management capacity, and decentralization affect the annual change in the satellite-derived Normalized Difference Vegetation Index (NDVI). NDVI varies with greenness that relates to plant production, biomass, and important ecosystem functions related to biodiversity and ecosystem services such as water quality and carbon storage. Any loss of vegetation cover in the form of deforestation or degradation would show up as a decrease in NDVI values over time and gains in vegetation cover and regeneration as an increase in NDVI values. Management restriction categories are based on international classifications of strict versus multiple-use PAs, and capacity and decentralization categories are based on key informant interviews of PA managers. We use matching to create a counterfactual of non-protected observations and a matching estimator and regression to estimate treatment effects of each sub-sample. On average, strict and multiple-use PAs have a significant and positive effect on NDVI compared to non-protected land uses. Both high and low decentralized PAs also positively affect NDVI. High capacity PAs have a positive and significant effect on NDVI, while low capacity PAs have a negative effect on NDVI. Our findings advance knowledge on how governance and management influence PA effectiveness and suggest that capacity may be more important than governance type or management restrictions in maintaining and enhancing NDVI. This paper also provides a guide for future studies to incorporate measures of PA governance and management into impact evaluations.
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Conservación de los Recursos Naturales , Ecosistema , América Central , Intervalos de Confianza , Geografía , PlantasRESUMEN
INTRODUCTION AND AIM: Sarcopenia is an independent predictor of mortality in cirrhosis. Hypogonadism is common in cirrhosis and has been associated with sarcopenia in non-cirrhotic chronic liver disease populations. The aim of this study is to investigate if sarcopenia is associated with low testosterone levels in patients with cirrhosis. MATERIAL AND METHODS: This is a retrospective analysis of prospectively collected data of 211 cirrhotic patients undergoing evaluation for liver transplantation. Sarcopenia was defined by computed tomography (CT) scan using specific cutoffs of the 3rd lumbar vertebra skeletal muscle index (L3 SMI). Morning testosterone levels were obtained in all patients. RESULTS: Of the 211 patients, sarcopenia was noted in 94 (45%). Testosterone levels were lower in sarcopenic patients (10.7 ± 1.1 vs. 13.7 ± 1.4 nmol/L, p = 0.03) and hypotestosteronemia was more frequent in them too (34 vs. 16%, p = 0.004). In males, those with sarcopenia had lower testosterone levels (14.6 ± 1.4 vs. 21.9 ± 1.8, p = 0.002), and the corresponding frequency of hypotestosteronemia (42 vs. 19%, p = 0.006) was also higher. There were no significant differences in female patients. There was a weak correlation between L3 SMI and testosterone levels (r 0.37, p < 0.001). On multivariable regression analysis including sex, body mass index (BMI), hypotestosteronemia, MELD and etiology of cirrhosis, only hypotestosteronemia (RR 2.76, p = 0.005) and BMI (RR 0.88, p < 0.001) were independently associated with sarcopenia. CONCLUSION: Low testosterone levels are associated with sarcopenia in male cirrhotic patients. The potential therapeutic effect of testosterone to reverse sarcopenia in these patients warrants evaluation in future trials.
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Composición Corporal , Hipogonadismo/sangre , Cirrosis Hepática/complicaciones , Músculo Esquelético/fisiopatología , Sarcopenia/fisiopatología , Testosterona/deficiencia , Biomarcadores/sangre , Estudios Transversales , Femenino , Humanos , Hipogonadismo/diagnóstico , Hipogonadismo/etiología , Cirrosis Hepática/diagnóstico , Masculino , Persona de Mediana Edad , Músculo Esquelético/diagnóstico por imagen , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Sarcopenia/diagnóstico por imagen , Sarcopenia/etiología , Testosterona/sangre , Tomografía Computarizada por Rayos XRESUMEN
INTRODUCTION AND AIM: Sofosbuvir (SOF)-based regimen has been shown to have high efficacy even in patients with decompensated cirrhosis. Treated patients may experience various degrees of hepatic recovery ranging from stabilization of liver function, to removal from liver transplant wait lists. The frequency of these occurrences in larger transplant eligible patient populations is unknown. The aim of this study was to assess the efficacy of SOF-based therapy in HCV infected transplant eligible patients and to evaluate short term changes in liver function and the effect on their liver transplant status. MATERIAL AND METHODS: A retrospective multicenter Canadian study of liver transplant candidates with advanced HCV cirrhosis treated with SOF-based therapy. Outcomes included sustained virologic response (SVR), and liver transplant status. RESULTS: 105 liver transplant candidates with advanced liver disease due to HCV were evaluated. The overall SVR was 83.8%. Hepatocellular carcinoma was diagnosed in 39 (37.1%) prior to transplant evaluation. In short term follow-up, 14 (13.3%) remained active on the list at the time of SVR12, 22 (20.9%) patients underwent liver transplantation, 7 (6.6%) patients were deactivated due to clinical improvement, 3 patients were delisted, and 10 deaths were reported. CONCLUSIONS: SOF-based therapy for patients progressing to liver transplantation leads to high SVR rates, short term stability in liver function, and deactivation from the transplant list .
Asunto(s)
Antivirales/uso terapéutico , Hepatitis C/tratamiento farmacológico , Cirrosis Hepática/tratamiento farmacológico , Trasplante de Hígado , Sofosbuvir/uso terapéutico , Adulto , Anciano , Antivirales/efectos adversos , Canadá , Progresión de la Enfermedad , Quimioterapia Combinada , Femenino , Hepatitis C/diagnóstico , Hepatitis C/mortalidad , Hepatitis C/virología , Humanos , Cirrosis Hepática/diagnóstico , Cirrosis Hepática/mortalidad , Cirrosis Hepática/virología , Pruebas de Función Hepática , Masculino , Persona de Mediana Edad , Recuperación de la Función , Estudios Retrospectivos , Factores de Riesgo , Sofosbuvir/efectos adversos , Respuesta Virológica Sostenida , Factores de Tiempo , Resultado del Tratamiento , Listas de EsperaRESUMEN
INTRODUCTION: Quantitative hepatitis B surface antigen (qHBsAg) combined with HBV DNA may be useful for predicting chronic hepatitis B (CHB) activity and nucleoside analogue (NA) response. MATERIAL AND METHODS: In this retrospective cohort study we evaluated qHBsAg levels according to CHB disease phase and among patients on treatment. Random effect logistic regression analysis was used to analyze qHBsAg change with time in the NA-treated cohort. RESULTS: 545 CHB carriers [56% M, median age 48 y (IQR 38-59), 73% Asian] had qHBsAg testing. In the untreated group (44%), 8% were classified as immune tolerant, 10% immune clearance, 40% inactive, and 43% had HBeAg- CHB and the median HBsAg levels were 4.6 (IQR 3.4-4.9), 4.0 (IQR 3.4-4.5), 2.9 (IQR 1.4-3.8), and 3.2 log IU/mL (IQR 2.6-4.0), respectively; p < 0.001. In the NA-treated group (28% entecavir, 68% tenofovir, 4% lamivudine), no significant change in qHBsAg levels occured with time. However, 19% of patients on long-term NA had sustained qHBsAg < 2 log10 IU/mL. CONCLUSION: qHBsAg titers were associated with CHB phase and remained stable in those on long-term NA. A significant number of treated patients had low-level qHBsAg, of which some may be eligible for treatment discontinuation without risk of flare.
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Antivirales/uso terapéutico , Monitoreo de Drogas/métodos , Antígenos de Superficie de la Hepatitis B/sangre , Virus de la Hepatitis B/efectos de los fármacos , Hepatitis B Crónica/tratamiento farmacológico , Adulto , Biomarcadores/sangre , Canadá/epidemiología , ADN Viral/genética , Femenino , Estudios de Seguimiento , Virus de la Hepatitis B/genética , Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/diagnóstico , Hepatitis B Crónica/epidemiología , Hepatitis B Crónica/virología , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento , Carga ViralRESUMEN
The clinical characteristics of chronic myeloid leukemia (CML) in lymphoid blast crisis (BC) can resemble those of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph ALL). Because of this, there can be concern as to whether a patient with newly diagnosed Ph leukemia has Ph ALL or CML in lymphoid BC. This distinction has significant potential therapeutic implications because most children with Ph ALL are now treated with chemotherapy plus a tyrosine kinase inhibitor, whereas allogeneic stem cell transplant is usually recommended for any patient with CML that presents in or later develops BC.
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Crisis Blástica/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Cromosoma Filadelfia , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Adolescente , Niño , Proteínas de Fusión bcr-abl/genética , Humanos , MasculinoRESUMEN
Deforestation and conversion of native habitats continues to be the leading driver of biodiversity and ecosystem service loss. A number of conservation policies and programs are implemented--from protected areas to payments for ecosystem services (PES)--to deter these losses. Currently, empirical evidence on whether these approaches stop or slow land cover change is lacking, but there is increasing interest in conducting rigorous, counterfactual impact evaluations, especially for many new conservation approaches, such as PES and REDD, which emphasize additionality. In addition, several new, globally available and free high-resolution remote sensing datasets have increased the ease of carrying out an impact evaluation on land cover change outcomes. While the number of conservation evaluations utilizing 'matching' to construct a valid control group is increasing, the majority of these studies use simple differences in means or linear cross-sectional regression to estimate the impact of the conservation program using this matched sample, with relatively few utilizing fixed effects panel methods--an alternative estimation method that relies on temporal variation in the data. In this paper we compare the advantages and limitations of (1) matching to construct the control group combined with differences in means and cross-sectional regression, which control for observable forms of bias in program evaluation, to (2) fixed effects panel methods, which control for observable and time-invariant unobservable forms of bias, with and without matching to create the control group. We then use these four approaches to estimate forest cover outcomes for two conservation programs: a PES program in Northeastern Ecuador and strict protected areas in European Russia. In the Russia case we find statistically significant differences across estimators--due to the presence of unobservable bias--that lead to differences in conclusions about effectiveness. The Ecuador case illustrates that if time-invariant unobservables are not present, matching combined with differences in means or cross-sectional regression leads to similar estimates of program effectiveness as matching combined with fixed effects panel regression. These results highlight the importance of considering observable and unobservable forms of bias and the methodological assumptions across estimators when designing an impact evaluation of conservation programs.
Asunto(s)
Conservación de los Recursos Naturales/métodos , Estudios Transversales , Ecosistema , Ecuador , Análisis de Regresión , Federación de RusiaRESUMEN
INTRODUCTION: Hepatitis C (HCV) continues to be the leading indication for liver transplantation (LT). Sustained virological response (SVR) rates to pegylated interferon (PEG-IFN) and ribavirin (RBV) therapy for recurrent HCV in Genotype 1 (G1) LT recipients have been disappointing (30-40%). Experience with triple therapy using protease inhibitors (PI) boceprevir (BOC), telaprevir (TVR) in these patients has been limited. MATERIAL AND METHODS: This national multicenter retrospective study included 76 patients (64 male, mean age 57 ± 6 years), treated for G1 HCV recurrence with either BOC (n = 41) or TVR (n = 35), who were non-responders or relapsers (n = 54), treatment naïve (n = 22) or had fibrosing cholestatic HCV (n = 3). 53 patients were on cyclosporine, 22 on tacrolimus and one patient on prednisone alone. RESULTS: On treatment virologic response was observed in 84% (64/76), 83% in BOC and 85% in TVR group. A higher week 4 response after starting triple therapy (RVR) was noted in TVR group 25/35 (81%) as compared to BOC group 26/41 (63%); p value = 0.02. The end of treatment response was 78% and 75% in BOC and TVR group, respectively. SVR 12 weeks after treatment discontinuation was observed in 59.5% (22/37); 58.3% in the BOC group and 61.5% in TVR group. Treatment was discontinued early in 23 patients (serious adverse effects n = 19, treatment failure n = 4). Infections occurred in 5 patients with 2 deaths (all in BOC). Anemia was the most common side effect (n = 55, 72%) requiring erythropoietin and RBV dose reduction. In the BOC group, cyclosporine dose reduction was 2.2 ± 1.0 fold and 8.6 ± 2.4 fold with tacrolimus. In TVR group, dose reduction was 3.0 ± 1.4 with cyclosporine and 12 ± 5.7 fold with tacrolimus. CONCLUSIONS: PI-based triple therapy appears more effective in producing HCV-RNA clearance than dual therapy. Tolerability is a serious issue and drug-drug interactions are manageable with close monitoring.
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Antivirales/uso terapéutico , Enfermedad Hepática en Estado Terminal/cirugía , Hepacivirus/efectos de los fármacos , Hepatitis C Crónica/tratamiento farmacológico , Trasplante de Hígado/efectos adversos , Oligopéptidos/uso terapéutico , Prolina/análogos & derivados , Inhibidores de Proteasas/uso terapéutico , Activación Viral/efectos de los fármacos , Antivirales/efectos adversos , Canadá , Proteínas Portadoras/antagonistas & inhibidores , Proteínas Portadoras/metabolismo , Interacciones Farmacológicas , Quimioterapia Combinada , Enfermedad Hepática en Estado Terminal/virología , Femenino , Hepacivirus/enzimología , Hepacivirus/genética , Hepatitis C Crónica/complicaciones , Hepatitis C Crónica/diagnóstico , Humanos , Inmunosupresores/uso terapéutico , Péptidos y Proteínas de Señalización Intracelular , Masculino , Persona de Mediana Edad , Oligopéptidos/efectos adversos , Prolina/efectos adversos , Prolina/uso terapéutico , Inhibidores de Proteasas/efectos adversos , ARN Viral/sangre , Recurrencia , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento , Carga Viral , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/metabolismoRESUMEN
Extramedullary manifestations of acute myeloid leukemia (AML), often referred to as myeloid sarcoma (MS), occur relatively commonly in children with newly diagnosed or relapsed AML and have been associated with certain French-American-British morphologies and gene/chromosomal rearrangements. The most common locations of MS include the skin, orbit, skeleton, central nervous system, skin, and gut. Pulmonary MS is uncommon in adults and is extremely rare in children. We report the case of a 19-year-old man with French-American-British M5 AML, who before bone marrow transplant, presented with fever, hypotension, and respiratory symptoms that were ultimately attributed to pulmonary MS.
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Trasplante de Médula Ósea , Leucemia Monocítica Aguda/terapia , Neoplasias Pulmonares/diagnóstico , Recurrencia Local de Neoplasia/diagnóstico , Sarcoma Mieloide/diagnóstico , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Masculino , Pronóstico , Sarcoma Mieloide/tratamiento farmacológico , Adulto JovenAsunto(s)
Hipertensión/etiología , Aparato Yuxtaglomerular/patología , Neoplasias Renales/complicaciones , Neoplasias Renales/patología , Adolescente , Biopsia con Aguja , Determinación de la Presión Sanguínea , Femenino , Estudios de Seguimiento , Humanos , Hipertensión/fisiopatología , Inmunohistoquímica , Neoplasias Renales/cirugía , Nefrectomía/métodos , Enfermedades Raras , Sistema Renina-Angiotensina , Medición de Riesgo , Índice de Severidad de la Enfermedad , Resultado del TratamientoRESUMEN
The pathological findings in sheep with peracute experimental Clostridium perfringens type D enterotoxemia are described. Of 16 animals inoculated intraduodenally with a whole culture of this microorganism and a starch solution in the abomasum, 12 developed clinical signs including increased respiratory efforts, recumbency, paddling, bleating, convulsions, blindness, and opisthotonus. Diarrhea was not observed in any of the animals. The time lapse between the beginning of intraduodenal infusion and onset of clinical signs varied between 30 minutes and 26 hours, and the clinical course varied between 1 and 9 hours. Gross postmortem changes were observed in these 12 animals and included pulmonary edema; excess pericardial, peritoneal, or pleural fluid with or without strands of fibrin; liquid small intestinal contents; leptomeningeal edema; cerebellar coning; and subcapsular petechiae on kidneys. Histological changes consisted of severe edema of pleura and interlobular septa and around blood vessels and airways and acidophilic, homogeneous, proteinaceous perivascular edema in the brain. Five of 12 animals (42%) with clinical signs consistent with enterotoxemia lacked specific histological lesions in the brain. None of the intoxicated or control animals developed nephrosis. Glucose was detected in the urine of 3 of 6 animals that were tested for this analyte. These results stress the importance of the use of histological examination of the brain, coupled with epsilon toxin detection, for a definitive diagnosis of C. perfringens type D enterotoxemia in sheep.
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Infecciones por Clostridium/patología , Infecciones por Clostridium/veterinaria , Clostridium perfringens/crecimiento & desarrollo , Enterotoxemia/microbiología , Enterotoxemia/patología , Enfermedades de las Ovejas/microbiología , Enfermedades de las Ovejas/patología , Animales , Toxinas Bacterianas/sangre , Encéfalo/microbiología , Encéfalo/patología , Infecciones por Clostridium/microbiología , Infecciones por Clostridium/orina , Enterotoxemia/orina , Ensayo de Inmunoadsorción Enzimática/veterinaria , Femenino , Tracto Gastrointestinal/microbiología , Tracto Gastrointestinal/patología , Glucosuria/veterinaria , Histocitoquímica/veterinaria , Riñón/microbiología , Riñón/patología , Pulmón/microbiología , Pulmón/patología , Masculino , Ratones , Pruebas de Neutralización , Distribución Aleatoria , OvinosRESUMEN
In cattle, a neurological lesion similar to that produced in sheep and goats by Clostridium perfringens type D enterotoxaemia has been reported. However, no causal relationship has been established between this disease and the lesion in cattle. The effects of single and multiple intravenous injections of epsilon toxin in three calves aged 6 months were studied. A further calf was inoculated intravenously with saline solution and used as a control. Epsilon toxin invariably produced neurological signs within 2-60 min of the end of the injection process. Clinical signs consisted of loss of consciousness, recumbency, convulsions, paddling, opisthotonus, hyperaesthesia and dyspnoea. Gross changes consisted of severe acute pulmonary oedema, which was particularly marked in the interlobular septa. The histological lesions consisted of intra-alveolar and interstitial oedema of the lung and variable degrees of perivascular proteinaceous oedema in the internal capsule, thalamus and cerebellar white matter. No clinical or post-mortem changes were observed in the control calf. These results show that calves are susceptible to the intravenous injection of epsilon toxin, and that they can show at least some of the histological lesions produced in sheep and goats by this toxin.
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Toxinas Bacterianas/toxicidad , Enfermedades de los Bovinos/patología , Enfermedades de los Bovinos/fisiopatología , Infecciones por Clostridium/veterinaria , Clostridium perfringens , Enfermedad Aguda , Animales , Toxinas Bacterianas/administración & dosificación , Edema Encefálico/inducido químicamente , Edema Encefálico/patología , Edema Encefálico/fisiopatología , Edema Encefálico/veterinaria , Bovinos , Enfermedades de los Bovinos/microbiología , Infecciones por Clostridium/microbiología , Infecciones por Clostridium/patología , Infecciones por Clostridium/fisiopatología , Inyecciones Intravenosas , Masculino , Edema Pulmonar/inducido químicamente , Edema Pulmonar/patología , Edema Pulmonar/veterinariaRESUMEN
A retrospective study was performed on skin samples from an outbreak of cutaneous papillomatosis in Merino sheep that occurred in 1995. The samples were processed for routine histology, electron microscopy and immunocytochemistry for papilloma viruses. Particles of approximately 55 nm diameter were found in some nuclei of the stratum granulosum cells, while immunocytochemistry gave positive staining of cell nuclei in this layer. This study confirms that papillomas associated with papillomaviruses occur in sheep in Patagonia.
Asunto(s)
Brotes de Enfermedades/veterinaria , Papiloma/veterinaria , Enfermedades de las Ovejas/epidemiología , Neoplasias Cutáneas/veterinaria , Animales , Argentina/epidemiología , Papiloma/epidemiología , Papiloma/virología , Papillomaviridae/aislamiento & purificación , Estudios Retrospectivos , Ovinos , Enfermedades de las Ovejas/patología , Enfermedades de las Ovejas/virología , Piel/patología , Neoplasias Cutáneas/epidemiología , Neoplasias Cutáneas/virologíaAsunto(s)
Alprostadil/uso terapéutico , Mano/irrigación sanguínea , Isquemia/tratamiento farmacológico , Síndrome Mucocutáneo Linfonodular/complicaciones , Humanos , Lactante , Isquemia/complicaciones , Masculino , Síndrome Mucocutáneo Linfonodular/tratamiento farmacológico , gammaglobulinas/uso terapéuticoRESUMEN
Ventricular myosin ATPase activity, V1 isomyosin content and serum T3 (tri-iodothyronine) values decrease with age in male Fischer 344 rats. To determine if the age decrement in ATPase activity and V1 isomyosin content are caused by decreased T3 levels or an age-related decrease in V1 isomyosin induction by T3, 3-, 12- and 24-month-old male Fischer 344 rats were given constant T3 infusions by osmotic minipump. Rats at all ages were given 0.75, 5 and 15 micrograms(/100 g per 24 h) doses of T3, whereas 12- and 24-month-old rats were given an additional 0.4 microgram dose. In control rats, T3 levels decreased from 97 +/- 2.7 at 3 months to 75 +/- 4.7 ng/100 ml at 24 months. Likewise, Ca2+-activated myosin ATPase activity decreased from 1.04 +/- 0.05 to 0.68 +/- 0.05 mumol of Pi/min per mg of protein, and the relative proportion of V1 of isomyosin decreased from 90 +/- 4.0 to 26 +/- 2.0%. The lowest (0.4 microgram) T3 dose, which was sufficient to restore T3 levels in 24-month-old animals to 3-month control values, abolished the age decrement in myosin ATPase activity and markedly increased the proportion of V1 isomyosin present in the ventricle. These findings indicate that the senescent ventricle responds readily to small doses of T3 and strongly suggest that the age decrement in serum T3 levels is sufficient to contribute to the age-related decrease in myosin ATPase activity and V1 isomyosin content. Since these parameters correlate with ventricular contractility, the age decrement in T3 levels may also contribute to the decreased ventricular contractility and cardiac output observed in senescent rats.