RESUMEN

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sparse data. We collected standardized surveys of herbivory for 503 plant species at 790 sites across 116° of latitude. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth.

Asunto(s)

Variación Biológica Poblacional , Herbivoria , Defensa de la Planta contra la Herbivoria , Plantas , Ecosistema , Filogenia , Animales , Evolución Biológica

Asunto(s)

Hepatitis/microbiología , Sífilis , Adolescente , Hepatitis/diagnóstico , Humanos , Masculino , Sífilis/diagnóstico

RESUMEN

BACKGROUND/OBJECTIVES: The common non-coding single nucleotide polymorphism (SNP) rs3129882 in HLA-DRA is associated with risk for idiopathic Parkinson's disease (PD). The location of the SNP in the major histocompatibility complex class II (MHC-II) locus implicates regulation of antigen presentation as a potential mechanism by which immune responses link genetic susceptibility to environmental factors in conferring lifetime risk for PD. METHODS: For immunophenotyping, blood cells from 81 subjects were analyzed by qRT-PCR and flow cytometry. A case-control study was performed on a separate cohort of 962 subjects to determine association of pesticide exposure and the SNP with risk of PD. RESULTS: Homozygosity for G at this SNP was associated with heightened baseline expression and inducibility of MHC class II molecules in B cells and monocytes from peripheral blood of healthy controls and PD patients. In addition, exposure to a commonly used class of insecticide, pyrethroids, synergized with the risk conferred by this SNP (OR = 2.48, p = 0.007), thereby identifying a novel gene-environment interaction that promotes risk for PD via alterations in immune responses. CONCLUSIONS: In sum, these novel findings suggest that the MHC-II locus may increase susceptibility to PD through presentation of pathogenic, immunodominant antigens and/or a shift toward a more pro-inflammatory CD4+ T cell response in response to specific environmental exposures, such as pyrethroid exposure through genetic or epigenetic mechanisms that modulate MHC-II gene expression.

RESUMEN

BACKGROUND AND PURPOSE: Head injury has been linked to Parkinson's disease (PD) in some but not all studies. Differences in the genetic and environmental susceptibility to PD between populations might be one explanation. The joint effects of head injuries and SNCA genetic variants were investigated. METHODS: From 2001 to 2012, 561 incident idiopathic PD cases and 721 population controls from central California were enrolled. Subjects reported on head injuries throughout their lifetime and were assessed for genetic variability in the SNCA 5' region (D4S3481; Rep1) and 3' untranslated region (rs356165). In unconditional logistic regression models adjusted for confounders, interactions between head injuries and genetic risk variants were investigated. RESULTS: Parkinson's disease risk in individuals with head injury who are carriers of at least one 263 bp allele in D4S3481 or rs356165 variants was 3-4.5-fold higher compared with non-carriers without head injuries. However, tests for interaction between head injury and SNCA D4S3481or rs356165 were not statistically significant. CONCLUSIONS: Our study finds some evidence that head injury and D4S3481 or rs356165 variants jointly increase the risk of PD but little evidence of interaction.

Asunto(s)

Traumatismos Craneocerebrales/genética , Interacción Gen-Ambiente , Enfermedad de Parkinson/genética , alfa-Sinucleína/genética , Anciano , Anciano de 80 o más Años , Traumatismos Craneocerebrales/complicaciones , Femenino , Variación Genética , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/etiología , Factores de Riesgo

RESUMEN

Ant protection of extrafloral nectar (EFN)-secreting plants is a common form of mutualism found in most habitats around the world. However, very few studies have considered these mutualisms from the ant, rather than the plant, perspective. In particular, a whole-colony perspective that takes into account the spatial structure and nest arrangement of the ant colonies that visit these plants has been lacking, obscuring when and how colony-level foraging decisions might affect tending rates on individual plants. Here, we experimentally demonstrate that recruitment of Crematogaster opuntiae (Buren) ant workers to the EFN-secreting cactus Ferocactus wislizeni (Englem) is not independent between plants up to 5 m apart. Colony territories of C. opuntiae are large, covering areas of up to 5,000 m(2), and workers visit between five and 34 EFN-secreting barrel cacti within the territories. These ants are highly polydomous, with up to 20 nest entrances dispersed throughout the territory and interconnected by trail networks. Our study demonstrates that worker recruitment is not independent within large polydomous ant colonies, highlighting the importance of considering colonies rather than individual workers as the relevant study unit within ant/plant protection mutualisms.

Asunto(s)

Hormigas/fisiología , Conducta Animal , Simbiosis , Animales , Néctar de las Plantas

RESUMEN

INTRODUCTION: Acute myocarditis is one of the less common extra-intestinal manifestations of inflammatory bowel diseases (IBD). It may reveal IBD or occur during the follow-up. CASE REPORTS: We report two patients who presented an acute myocarditis associated with ulcerative colitis that reveal the disease in one of them. Clinical features at presentation were non specific and both patients presented with chest pain. Diagnosis was obtained with cardiac MRI. Outcome was favourable in the two patients. CONCLUSION: Etiologies of myocarditis are various and the diagnosis of extra-intestinal manifestations related to IBD remains a diagnosis of exclusion. Cardiac MRI is an important diagnostic tool. Colchicine and acétylsalicylic acid are commonly prescribed in a first therapeutic approach.

Asunto(s)

Enfermedades Inflamatorias del Intestino/complicaciones , Miocarditis/complicaciones , Enfermedad Aguda , Adulto , Humanos , Enfermedades Inflamatorias del Intestino/diagnóstico por imagen , Imagen por Resonancia Magnética , Masculino , Miocarditis/diagnóstico por imagen , Radiografía , Adulto Joven

RESUMEN

Cirrhosis is a frequent and severe condition, which is the late stage of numerous chronic liver diseases. It is associated with major hemodynamic alterations characteristic of hyperdynamic circulation and with a series of structural, functional, electrophysiological and biological heart abnormalities termed cirrhotic cardiomyopathy. The pathogenesis of this syndrome is multifactorial. It is usually clinically latent or mild, likely because the peripheral vasodilatation significantly reduces the left ventricle afterload. However, sudden changes of hemodynamic state (vascular filling, surgical or transjugular intrahepatic porto-systemic shunts, peritoneo-venous shunts and orthotopic liver transplantation) or myocardial contractility (introduction of beta-blocker therapy) can unmask its presence, and sometimes convert latent to overt heart failure. Cirrhotic cardiomyopathy may also contribute to the pathogenesis of hepatorenal syndrome. This entity has been described recently, and its diagnostic criteria are still under debate. To date, current management recommendations are empirical, nonspecific measures. Recognition of cirrhotic cardiomyopathy depends on a high level of awareness for the presence of this syndrome, particularly in patients with advanced cirrhosis who undergo significant surgical, pharmacological or physiological stresses.

Asunto(s)

Cardiomiopatías/etiología , Cirrosis Hepática/complicaciones , Cardiomiopatías/diagnóstico , Electrocardiografía , Hemodinámica , Humanos , Hipertensión Portal/complicaciones , Hipertensión Portal/etiología , Cirrosis Hepática/cirugía , Trasplante de Hígado , Resistencia Vascular

RESUMEN

OBJECTIVE: The objective of this study was to examine risks of preterm births, quantify the explanatory power achieved by adding medical and obstetric risk factors to the models and to examine temporal changes in preterm birth due to changes in Medicaid eligibility and the establishment of a maternal-fetal medicine referral system. STUDY DESIGN: The study used data from the 2001 to 2005-linked Arkansas (AR) Medicaid claims and birth certificates of preterm and term singleton deliveries (N=89 459). Logistic regression modeled the association among gestational age, demographic characteristics and risk factors, pooled and separately by year. RESULT: Physiological risk factors were additive with demographic factors and explained more of the preterm birth ≤32 weeks than later preterm birth. Changing eligibility requirements for Medicaid recipients and increasing the financial threshold from 133 to 200% of federal poverty level had an impact on temporal changes. The proportion of births ≤32 weeks declined to 33%, from 3.0 to 2.0. However, later preterm births declined and then increased in the last year. CONCLUSION: Physiological conditions are strongly associated with early preterm birth. Maternal behaviors and other stressors are predictive of later preterm birth. Unmeasured effects of poverty continue to have a role in preterm birth. Further examination of the referral system is needed.

Asunto(s)

Trabajo de Parto Prematuro/epidemiología , Nacimiento Prematuro/epidemiología , Adolescente , Arkansas/epidemiología , Femenino , Edad Gestacional , Conductas Relacionadas con la Salud , Humanos , Recién Nacido , Recien Nacido Prematuro , Modelos Logísticos , Medicaid , Análisis Multivariante , Trabajo de Parto Prematuro/etnología , Embarazo , Nacimiento Prematuro/etnología , Nacimiento Prematuro/etiología , Factores de Riesgo , Factores Socioeconómicos , Estados Unidos , Adulto Joven

Asunto(s)

Hígado Graso/patología , Femenino , Humanos , Persona de Mediana Edad

RESUMEN

BACKGROUND: We constructed a cohort of first-degree relatives of participants in a population-based case-control study of Parkinson disease (PD) and compared the occurrence of Alzheimer disease (AD) and essential tremor (ET) in relatives of PD cases and controls. METHODS: We relied on proband interviews to assess family history in 372 probands with incident PD confirmed by a movement disorder specialist and 404 controls from three rural California counties. RESULTS: Overall, for the 2980 first-degree relatives of PD cases, the risk of AD was not increased compared with the 2981 relatives of controls. But relatives of younger onset PD cases (

Asunto(s)

Enfermedad de Alzheimer/epidemiología , Temblor Esencial/epidemiología , Enfermedad de Parkinson/epidemiología , Edad de Inicio , Anciano , Enfermedad de Alzheimer/genética , Estudios de Casos y Controles , Estudios de Cohortes , Temblor Esencial/genética , Femenino , Predisposición Genética a la Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/genética , Linaje , Factores de Riesgo

RESUMEN

We report a 38-year-old immunocompetent patient who presented with a neutropenic rectitis after a treatment by amoxicillin for nasopharyngitis. Neutropenic colitis is a digestive wall inflammation, preferentially localized in the ileo-caecal area and the right colon, which leads to necrosis and sepsis, and usually occurs in neutropenic patients treated by chemotherapy with an incidence of 6%. It is a serious and often lethal disease. The treatment is supportive, and surgery is limited to the occurrence of complications (perforation, bleeding). Neutropenic colitis occurring in a rectal location after antibiotic therapy in an immunocompetent patient has been rarely described.

Asunto(s)

Amoxicilina/efectos adversos , Antibacterianos/efectos adversos , Inmunocompetencia , Neutropenia/inducido químicamente , Proctitis/inducido químicamente , Adulto , Amoxicilina/administración & dosificación , Antibacterianos/administración & dosificación , Humanos , Transfusión de Leucocitos , Masculino , Nasofaringitis/tratamiento farmacológico , Neutropenia/patología , Neutropenia/terapia , Proctitis/patología , Proctitis/terapia , Proctoscopía , Resultado del Tratamiento

RESUMEN

Liver failure as a result of neoplasia is a rare event before the terminal stage of the illness. We report a 66-year-old man who presented with clinical features of acute liver failure as the initial manifestation of a small-cell lung carcinoma. Liver was enlarged without ascitis. Abdominal CT-scan revealed a massive hepatomegaly with multiple low-density wedge-shaped lesions. The patient developed stage 3 hepatic encephalopathy and died on day 4. The diagnosis was obtained with post-mortem study. A Medline search of acute liver failure due to small-cell carcinoma identified only 17 cases already published, with a universally poor prognosis.

Asunto(s)

Fallo Hepático Agudo/etiología , Neoplasias Hepáticas/secundario , Neoplasias Pulmonares/patología , Carcinoma Pulmonar de Células Pequeñas/patología , Carcinoma Pulmonar de Células Pequeñas/secundario , Anciano , Resultado Fatal , Encefalopatía Hepática/etiología , Hepatomegalia/diagnóstico por imagen , Humanos , Neoplasias Hepáticas/diagnóstico , Masculino , Radiografía

RESUMEN

Acute liver failure (ALF) is relatively frequent during heat stroke (HS). This risk must be emphasized, because its incidence is higher than is usually thought. In a recent study by Weigand et al, two cases were reported in which liver failure was the leading symptom. We have confirmed their conclusion in a study of 25 cases of HS with ALF, compared with 25 other cases without ALF. Moreover, we observed that hypophosphatemia on admission could predict occurrence of ALF during HS. As for clinical and other biological parameters, phosphatemia should be monitored for at least 3 d in all cases of HS, even when it is thought to be mild.

Asunto(s)

Golpe de Calor/complicaciones , Fallo Hepático Agudo/etiología , Adulto , Golpe de Calor/epidemiología , Humanos , Fallo Hepático Agudo/epidemiología , Masculino , Factores de Riesgo

RESUMEN

Generalized, facultative mutualisms are often characterized by great variation in the benefits provided by different partner species. This variation may be due to differences among species in the quality and quantity of their interactions, as well as their phenology. Many plant species produce extrafloral nectar, a carbohydrate-rich resource, to attract ant species that can act as "bodyguards" against a plant's natural enemies. Here, we explore differences in the quality and quantity of protective service that ants can provide a plant by contrasting the four most common ant visitors to Ferocactus wislizeni, an extrafloral nectary-bearing cactus in southern Arizona. The four species differ in abundance when tending plants, and in the frequency at which they visit plants. By adding surrogate herbivores (Manduca sexta caterpillars) to plants, we demonstrate that all four species recruit to and attack potential herbivores. However, their per capita effectiveness in deterring herbivores (measured as the inverse of the number of workers needed to remove half of the experimentally added caterpillars) differs. Using these among-species differences in quality (per capita effectiveness) and quantity (number of workers that visit a plant and frequency of visitation), we accurately predicted the variation in fruit production among plants with different histories of ant tending. We found that plant benefits (herbivore removal and maturation of buds and fruits) typically saturated at high levels of ant protection, although plants could be "well defended" via different combinations of interaction frequency, numbers of ant workers per interaction, and per capita effects. Our study documents variation among prospective mutualists, distinguishes the components of this variation, and integrates these components into a predictive measure of protection benefit to the plant. The method we used to average saturating benefits over time could prove useful for quantifying overall service in other mutualisms.

Asunto(s)

Hormigas/fisiología , Cactaceae/fisiología , Simbiosis , Animales , Cactaceae/parasitología , Funciones de Verosimilitud , Especificidad de la Especie

RESUMEN

Screening for hepatitis B (HBV) surface antigen (Ag HBs) and for antibodies to hepatitis C (HCV) and human: immunodeficiency virus (HIV) was carried out in 9006 volunteer blood donors at the National Blood Bank in the Republic of Djibouti from 1998 to 2000. Results demonstrated the presence of Ag HBs in 934 patients (10.4%), antibodies to HCV in 21 patients (0.3%), and antibodies to HIV in 175 patients (1.9%). In comparison with neighboring countries the prevalence of HBV, HCV, and HIV infection in Djibouti was low. These findings should be used to guide preventive action against these viral infections in the Republic of Djibouti. Estimations of HIV infection (11.7%) based on modeling by the World Health Organization should be reviewed.

Asunto(s)

Donantes de Sangre , Infecciones por VIH/epidemiología , Hepatitis B/epidemiología , Hepatitis C/epidemiología , Adolescente , Adulto , Anciano , Djibouti/epidemiología , Femenino , Anticuerpos Anti-VIH/sangre , Infecciones por VIH/sangre , Hepatitis B/sangre , Antígenos de Superficie de la Hepatitis B/sangre , Hepatitis C/sangre , Anticuerpos contra la Hepatitis C/sangre , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Seroepidemiológicos

RESUMEN

OSP/claudin-11 and PLP are both tetraspan proteins concentrated in CNS myelin. It has been proposed that they have a structural role in myelin formation and maintenance due to their localization and concentration in membrane sheaths. This hypothesis is not supported by the fact that both OSP/claudin-11- and PLP-null mice have relatively normal-appearing myelin and mild neurological deficits. Since both OSP/claudin-11 and PLP are abundant in myelin and have similar structures, the mild phenotypes of the knockout mice are likely due to compensatory mechanisms. Here we show that when both OSP/claudin-11 and PLP genes are knocked out, mice had severe neurological deficits, markedly abnormal myelin compaction, and smaller axon diameters. Interestingly, when either of these genes was knocked out, the expression of the other protein was increased. These data demonstrate that OSP/claudin-11 and PLP have essential structural functions in maintaining normal compact myelin and there is redundancy in their functions.

Asunto(s)

Sistema Nervioso Central/anomalías , Proteína Proteolipídica de la Mielina/genética , Vaina de Mielina/metabolismo , Fibras Nerviosas Mielínicas/metabolismo , Proteínas del Tejido Nervioso/genética , Malformaciones del Sistema Nervioso/metabolismo , Adaptación Fisiológica/fisiología , Animales , Axones/metabolismo , Axones/patología , Axones/ultraestructura , Membrana Celular/metabolismo , Membrana Celular/patología , Membrana Celular/ultraestructura , Tamaño de la Célula , Sistema Nervioso Central/metabolismo , Sistema Nervioso Central/patología , Claudinas , Eliminación de Gen , Regulación del Desarrollo de la Expresión Génica/genética , Proteínas de la Membrana/genética , Ratones , Ratones Noqueados , Microscopía Electrónica de Transmisión , Trastornos del Movimiento/genética , Trastornos del Movimiento/metabolismo , Trastornos del Movimiento/fisiopatología , Vaina de Mielina/patología , Vaina de Mielina/ultraestructura , Fibras Nerviosas Mielínicas/patología , Fibras Nerviosas Mielínicas/ultraestructura , Malformaciones del Sistema Nervioso/genética , Malformaciones del Sistema Nervioso/fisiopatología , Regulación hacia Arriba/fisiología

Asunto(s)

Inhibidores de Catecol O-Metiltransferasa , Catecoles/farmacología , Homocisteína/biosíntesis , Hiperhomocisteinemia/inducido químicamente , Hiperhomocisteinemia/tratamiento farmacológico , Levodopa/antagonistas & inhibidores , Anciano , Anciano de 80 o más Años , Antiparkinsonianos/efectos adversos , Antiparkinsonianos/antagonistas & inhibidores , Antiparkinsonianos/metabolismo , Carbidopa/farmacología , Catecol O-Metiltransferasa/metabolismo , Catecoles/uso terapéutico , Estudios de Cohortes , Interacciones Farmacológicas/fisiología , Quimioterapia Combinada , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Femenino , Homocisteína/sangre , Humanos , Hiperhomocisteinemia/sangre , Levodopa/efectos adversos , Levodopa/metabolismo , Masculino , Persona de Mediana Edad , Nitrilos , Resultado del Tratamiento

RESUMEN

We performed 118 consecutive DBS cases from November 1999 to June 2002. Intraoperatively there were 10 cases studied with fluoroscopy, 73 with 0.2 Tesla (T) MRI and 35 with 1.5 T MRI. Ten electrodes were secured by Medtronic caps, 25 by methyl methacrylate with titanium miniplates, and 82 by Navigus caps. The 3-dimensional displacement between the planned target and actual electrode position (3DD) was determined by fusing the postoperative MRI with the preoperative imaging. The 3DD for using Medtronic caps, methyl methacrylate with miniplates, and Navigus caps were 4.80 +/- 3.16, 2.64 +/- 1.26 and 2.23 +/- 1.15 mm (mean +/- SD), respectively. Navigus caps had statistically significant accuracy (P = 0.03) in holding the electrode when compared with Medtronic caps, and it facilitated electrode revision. The fixation devices significantly affect the final vertical position of the electrode. The 3DD for fluoroscopy, 0.2 T and 1.5 T MRI cases were 4.80 +/- 3.16, 2.31 +/- 1.21 and 2.34 +/- 1.14 mm (mean +/- SD), respectively. No statistically significant difference (P = 0.91) in 3DD was demonstrated between 0.2 T and 1.5 T MRI cases. The presence of intraoperative 1.5 T MRI allowed near real-time electrode position confirmation and early detection of hemorrhagic complications. Satisfactory microelectrode recording was feasible in low-field 0.2 T and high-field 1.5 T MRI environments. Further studies on performing DBS in real-time intraoperative MRI are warranted.

Asunto(s)

Estimulación Encefálica Profunda , Diencéfalo/cirugía , Fluoroscopía , Globo Pálido/cirugía , Imagen por Resonancia Magnética , Neuronavegación/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Diencéfalo/diagnóstico por imagen , Diencéfalo/patología , Electrodos Implantados , Femenino , Globo Pálido/diagnóstico por imagen , Globo Pálido/patología , Humanos , Masculino , Persona de Mediana Edad

RESUMEN

Multiple sclerosis (MS) is characterized by demyelination of the CNS with associated neurological deficits. Remyelination can occur but is often incomplete. The process of myelin repair requires the proliferation and migration of oligodendrocyte progenitor cells (OPC) into the lesion from the neighboring areas. OPC migration is altered by several factors, including antibodies that bind to OPC surface proteins. We have previously reported elevated anti-OSP/claudin-11 antibodies in the cerebrospinal fluid (CSF) of MS patients and that anti-OSP/claudin-11 antibodies generated in rabbits can inhibit OPC migration. In the study presented here, we investigated the effect of CSF IgG from MS patients and controls on OPC migration in culture. Rat OPC cultured with CSF from MS patients tended to migrate more than those cultured with control CSF, but this did not reach statistical significance. To determine whether the IgG fraction in the CSF influenced migration, we removed it using protein-A sepharose. A dramatic decrease in OPC migration was found in both MS (45 +/- 24 vs.16 +/- 9) and control (40 +/- 19 vs. 22 +/- 13) samples after IgG was removed (P <.05). Anti-OSP/claudin-11 antibody concentration did not significantly correlate with OPC migration. These data demonstrate that CSF IgG promotes OPC migration. Identification of the specific IgG fraction responsible for this effect could lead to novel therapies to promote recovery in MS.

Asunto(s)

Movimiento Celular/inmunología , Inmunoglobulina G/líquido cefalorraquídeo , Esclerosis Múltiple/líquido cefalorraquídeo , Esclerosis Múltiple/inmunología , Oligodendroglía/citología , Células Madre/citología , Adulto , Animales , Femenino , Humanos , Inmunoglobulina G/fisiología , Masculino , Persona de Mediana Edad , Oligodendroglía/inmunología , Ratas , Células Madre/inmunología

Asunto(s)

Anemia de Células Falciformes/diagnóstico , Personal Militar , Esferocitosis Hereditaria/diagnóstico , Infarto del Bazo/etiología , Adulto , Anemia de Células Falciformes/complicaciones , Humanos , Masculino , Esferocitosis Hereditaria/complicaciones