3,634 research outputs found
Toxicity of copaiba extracts to armyworm (Spodoptera frugiperda)
The objective of this study was to evaluate the effects of methanolic extracts from leaves, peels, seeds and pulps from fruits of Copaifera langsdorffii on Spodoptera frugiperda. Extracts derived from leaves and fruit peels were more toxic to S. frugiperda than the others. Hence, they were added to the artificial diet and used in further experiments with the second instar larvae of the insect, which presented larval growth reduction, prolonged period of development, increased mortality, and lower fertility and fecundity of adults. Lower egg viability was also observed when the insect was treated with extracts of leaves and fruit peels in the larvae stage. Moreover, when subjected to ultrastructural analysis under a scanning electron microscope, such eggs showed abnormalities in the aeropylar and micropylar regions. Both extracts also increased the excretion of protein in the insect feces and inhibited trypsin activity in the in vitro test. Consequently, C. langsdorffii presents potential to be used in the development of new products to control the fall armyworm.Key words: Copaifera langsdorffii, natural products, trypsin inhibitor, botanical insecticide
Experimental infection of Aedes albopictus (Diptera : Culicidae) larvae with the xiphidiocercariae of a hematolechid
Aedes albopictus larvae were exposed, either individually or in groups, to different concentrations of xiphidiocercariae of Haematoloechus sp. for parasitological studies. It was observed the acute lethal effect and some aspects of the host-parasite relationship, such as delay or progress in the host life cycle, the number and location of the metacercariae in the host, adult host malformations and the amount of metacercariae required to cause death. A delay in the cycle and a high mortality rate was in general observed. Inside the larvae, the metacercariae were found predominantly in the thorax, abdominal segments and in the head, along with a reduced number in the anal lobe and cervix. It was shown that in addition to the quantity, of metacercariae present, their location in the larvae was also relevant in the determination of mortality and anomalies. Malformed adults developed from larvae containing from one to three metacercariae.97457357
Spontaneous cytokine production in children according to biological characteristics and environmental exposures.
BACKGROUND: Environmental factors are likely to have profound effects on the development of host immune responses, with serious implications for infectious diseases and inflammatory disorders such as asthma. OBJECTIVE: This study was designed to investigate the effects of environmental exposures on the cytokine profile of children. METHODS: The study involved measurement of T helper (Th) 1 (interferon-gamma), 2 [interleukin (IL)-5 and IL-13], and the regulatory cytokine IL-10 in unstimulated peripheral blood leukocytes from 1,376 children 4-11 years of age living in a poor urban area of the tropics. We also assessed the impact of environmental exposures in addition to biological characteristics recorded at the time of blood collection and earlier in childhood (0-3 years before blood collection). RESULTS: The proportion of children producing IL-10 was greater among those without access to drinking water [p < 0.05, chi-square test, odds ratio (OR) = 1.67]. The proportion of children producing IL-5 and IL-10 (OR = 10.76) was significantly greater in households that had never had a sewage system (p < 0.05, trend test). CONCLUSIONS: These data provide evidence for the profound effects of environmental exposures in early life as well as immune homeostasis in later childhood. Decreased hygiene (lack of access to clean drinking water and sanitation) in the first 3 years of life is associated with higher spontaneous IL-10 production up to 8 years later in life
Comparative fitness analysis of D-cycloserine resistant mutants reveals both fitness-neutral and high-fitness cost genotypes
Drug resistant infections represent one of the most challenging medical problems of our time. D-cycloserine is an antibiotic used for six decades without significant appearance and dissemination of antibiotic resistant strains, making it an ideal model compound to understand what drives resistance evasion. We therefore investigated why Mycobacterium tuberculosis fails to become resistant to D-cycloserine. To address this question, we employed a combination of bacterial genetics, genomics, biochemistry and fitness analysis in vitro, in macrophages and in mice. Altogether, our results suggest that the ultra-low rate of emergence of D-cycloserine resistance mutations is the dominant biological factor delaying the appearance of clinical resistance to this antibiotic. Furthermore, we also identified potential compensatory mechanisms able to minimize the severe fitness costs of primary D-cycloserine resistance conferring mutations
Accident caused by Rhopalurus agamemnon (Koch, 1839) (Scorpiones, Buthidae)
Acidentes escorpiônicos constituem um sério problema de saúde pública no Brasil. Rhopalurus agamemnon é um grande escorpião do bioma Cerrado, muito abundante em diversas localidades do Brasil Central. A espécie utiliza ambientes campestres e savânicos, sendo comum no interior de cupinzeiros. Entretanto, desaparece de locais onde o cerrado é removido. Os acidentes relatados apresentam sintomas de envenenamentos moderados, mas são baseados em identificações discutíveis. Aqui apresentamos o relato de um acidente seguramente causado por esta espécie. Concluímos que os poucos relatos disponíveis não permitem avaliar a gravidade dos acidentes e o eventual risco deste escorpião para a saúde pública. _________________________________________________________________________________ ABSTRACTAccidents caused by scorpions are a serious public health problem in Brazil. Rhopalurus agamemnon is a large scorpion found in the Cerrado (savanna) biome, and it is very abundant in many localities in central Brazil. The species inhabits open savanna environments, and is common inside termite mounds. However, it disappears from places where the native vegetation has been removed. The accidents reported present moderate symptoms of envenoming, but are based on questionable identifications. Here, we present a report on an accident that was certainly caused by Rhopalurus agamemnon. We conclude that the few reports available do not make it possible to evaluate the severity of such accidents and the possible risk to public health from this scorpion
Juvenile Batten disease (CLN3): Detailed Ocular Phenotype, Novel Observations, Delayed Diagnosis, Masquerades, and Prospects for Therapy
PURPOSE
To characterize the retinal phenotype of juvenile neuronal ceroid lipofuscinosis (JNCL), highlight delayed and mistaken diagnosis, and propose an algorithm for early identification.
DESIGN
Retrospective case series.
SUBJECTS
Eight children (5 females) with JNCL.
METHODS
Review of clinical notes, retinal imaging including fundus autofluorescence (FAF) and optical coherence tomography (OCT), electroretinography (ERG), and both microscopy and molecular genetic testing.
MAIN OUTCOME MEASUREMENTS
Demographic data, signs and symptoms, visual acuity, FAF and OCT findings, ERG phenotype, and microscopy/molecular genetics.
RESULTS
Subjects presented with rapid bilateral vision loss over one to eighteen months, with mean visual acuity deteriorating from 0.44 LogMAR (range: 0.20 - 1.78 LogMAR) at baseline, to 1.34 LogMAR (0.30 LogMAR - light perception) at last follow-up. Age of onset ranged from 3 to 7 years (mean 5.3 years). The age at diagnosis of JNCL ranged from 7 to 10 years (mean 8.3 years). Six children displayed eccentric fixation, and six had cognitive or neurological signs at time of diagnosis (75%). Seven patients had bilateral bull’s-eye maculopathy at presentation. Coats-like exudative vasculopathy, not previously reported in JNCL, was observed in one patient. OCT imaging revealed near complete loss of outer retinal layers, and marked atrophy of the nerve fibre and ganglion cell layers, at the central macula. An ‘electronegative’ ERG was present in four patients (50%), but with additional a-wave reduction; there was an undetectable ERG in the remaining four. Blood film microscopy revealed vacuolated lymphocytes and electron microscopy showed lysosomal (fingerprint) inclusions, in all eight patients.
CONCLUSIONS
In a young child with bilateral rapidly progressive vision loss and macular disturbance, blood film microscopy to detect vacuolated lymphocytes is a rapid, readily accessible, and sensitive screening test for JNCL. Early suspicion of JNCL can be aided by detailed directed history and high-resolution retinal imaging, with subsequent targeted microscopy/genetic testing. Early diagnosis is critical to ensure appropriate management, counselling, support and social care for children and their families. Furthermore, although potential therapies for this group of disorders are in early phase clinical trial, realistic expectations are that successful intervention will be most effective when initiated at the earliest stage of disease
The course of specialization in public health in Rio de Janeiro, Brazil, from 1926 to 2006: lessons and challenges
<p>Abstract</p> <p>Background</p> <p>Public health, as a field of knowledge, depends on its professionals. Their education and training, therefore, is considered to be an important factor for the quality of health services. In Brazil, the Course of Specialization in Public Health of the National School of Public Health is one of the oldest in the country. The course has existed for over 80 years, during which it has had an eventful history, with modifications in its organization, interruptions in its delivery, threats to its survival and changes in the institutions hosting it, reflecting the wider transformation in Brazilian society and public life over that period.</p> <p>Methods</p> <p>In this article we analyse this course via its history, disciplines, organization and characteristics of the student body.</p> <p>Results</p> <p>Insights were gained into the advancement of public health in Brazil and the progress of education for professionals in this field was highlighted. The course has formed nearly 2000 specialists in public health.</p> <p>Conclusions</p> <p>An analysis of the course's history provides valuable lessons for other schools of public health trying to train professionals in developing countries.</p
Postcopulatory sexual selection
The female reproductive tract is where competition between the sperm of different males takes place, aided and abetted by the female herself. Intense postcopulatory sexual selection fosters inter-sexual conflict and drives rapid evolutionary change to generate a startling diversity of morphological, behavioural and physiological adaptations. We identify three main issues that should be resolved to advance our understanding of postcopulatory sexual selection. We need to determine the genetic basis of different male fertility traits and female traits that mediate sperm selection; identify the genes or genomic regions that control these traits; and establish the coevolutionary trajectory of sexes
- …