Difference between heartwood and sapwood
Forest Products Laboratory (U.S.)
1919
Search results
45 records were found.
Particular interest has been raised in the last few years, regarding the contribution of the immune
system in neurological and psychiatric diseases. It is recognized that an inflammatory component
underlies disorders such as Alzheimer’s disease and multiple sclerosis. However, whether these
are a consequence, a cause, or just a trigger of disease progression remains to be clarified. In
this context, understanding how peripheral inflammatory stimulus reach the brain may contribute
to better understand the mechanisms involved in such conditions. Most studies on the
communication between the periphery and the central nervous system (CNS) focus on the bloodbrain
barrier, which is composed by the endothelial cells of the brain capillaries. However, the
blood-cerebrospinal fluid barrier (BCSFB) may as well convey signals from the periphery i...
Evidence from multiple lines of research supports the hypothesis that schizophrenia
arises from interactions between genetic and environmental factors during critical early periods of neuronal development.
Abnormal levels of thyroid hormones or retinoids during fetal development
have been suggested to contribute to the neurodevelopmental deviations found
in schizophrenic patients. In fact, thyroid hormones and retinoids could constitute
a functional link between genetic and environmental risk factors in schizophrenia.
This is an attractive hypothesis capable of explaining several epidemiological
features of the disease.
Thyroid hormones and retinoids are involved in the regulation of central nervous system function probably through their capacity to modulate the expression of several genes. To investigate if genes involved in the metab...
Dissertação de mestrado em Ciências da Saúde
In the mammalian brain adult neurogenesis occurs in two restricted sites: the subependymal
zone (SEZ) and the subgranular zone of the hippocampal dentate gyrus. The SEZ comprises
neural stem and progenitor cells that lie adjacent to the ependyma layer of the lateral ventricles.
SEZ born neuroblasts migrate anteriorly in the rostral migratory stream towards the olfactory
bulbs where they differentiate and integrate into neuronal circuitries. Because cells in the SEZ
niche sense alterations in brain homeostasis and are able to alter their proliferative, migratory
and differentiation profiles in response to injury, it is of particular interest to completely
understand this dynamics both in physiological and pathological conditions. In this context, the
present thesis addresses three main aspects in regard to SEZ niche complexity and modul...
Phenotypic discordance for schizophrenia in monozygotic twins clearly indicates
involvement of environmental factors as key determinants in disease development.
Positive findings from genome scans, linkage and association studies apply in only a
minority of those affected, while post-mortem brain investigations reveal altered
expression of genes and proteins involved in numerous neurodevelopmental, metabolic
and neurotransmitter pathways. Such altered expressions could result, on the one hand,
from mutations in coding regions or polymorphisms in the promoter and regulatory regions
in genes within those areas identified by gene searches or, on the other hand, from
inadequate amounts of modulators, transporters and synthesizers of transcription factors
necessary for regulation of the putative genes. Hormones and vitamins are such
modulat...
The ability to manage the constantly growing clinically relevant information in genetics available on the internet is becoming crucial in medical practice. Therefore, training students in teaching environments that develop bioinformatics skills is a particular challenge to medical schools. We present here an instructional approach that potentiates learning of hormone/vitamin mechanisms of action in gene regulation with the acquisition and practice of bioinformatics skills. The activity is integrated within the study of the Endocrine System module. Given a nucleotide sequence of a hormone or vitamin-response element, students use internet databases and tools to find the gene to which it belongs. Subsequently, students search how the corresponding hormone/vitamin influences the expression of that particular gene and how a dysfunctional i...
Cardiovascular diseases are traditionally related to well known risk factors like dyslipidemia, smoking, diabetes and hypertension. More recently, stress, anxiety and depression have been proposed as risk factors for cardiovascular diseases including heart failure, ischemic disease, hypertension and arrhythmias. Interestingly, this association has been established largely on the basis of epidemiological data, due to insufficient knowledge on the underlying pathophysiologic mechanisms. This review will revisit evidence on the interaction between the cardiovascular and nervous systems, highlighting the perspective on how the central nervous system is involved in the pathogenesis of cardiovascular diseases. Such knowledge is likely to be of relevance for the development of better strategies to treat patients in a holistic perspective.
The aging process correlates with a progressive failure in the normal cellular and organ functioning; these alterations are aggravated in Alzheimer’s disease (AD). In both aging and AD there is a general decrease in the capacity of the body to eliminate toxic compounds and, simultaneously, to supply the brain with relevant growth and nutritional factors. The barriers of the brain are targets of this age related dysfunction; both the endothelial cells of the blood–brain barrier and the choroid plexus epithelial cells of the blood-cerebrospinal fluid barrier decrease their secretory capacity towards the brain and their ability to remove toxic compounds from the brain. Additionally, during normal aging and in AD, the permeability of the brain barriers increase. As such, a greater contact of the brain parenchyma with the blood content alte...
OBJECTIVES:
To assess the psychomotor development of the progeny of women from a moderately iodine-deficient area for whom thyroid function during pregnancy was measured.
STUDY DESIGN:
The development of 86 children was assessed by the Bayley Scale of Infant Development at 12, 18, and 24 months.
RESULTS:
Maternal serum free thyroxine (FT(4)) levels in the first trimester of pregnancy were the major determinant of psychomotor development at 18 and 24 months. Children born from mothers with FT(4) levels <25th percentile (<10 pg/mL) had an OR of 2.1 for mild-to-severe delay. Furthermore, alterations in behavior were already observed at 12 months and were related to subsequent changes in development. Neonatal thyroid status did not influence development.
CONCLUSIONS:
This study highlights the need to implement active measures of iod...
Objectives To compare cortical maturation between fetuses with isolated mild ventriculomegaly (IMV) and healthy fetuses, and to explore its potential prognostic value in IMV.
Methods This prospective study quantified cortical maturation by ultrasound in 24 fetuses with IMV and 46 healthy fetuses. Depth and grading the developmental pattern of the parieto-occipital fissure (POF), calcarine fissure (CF) and sylvian fissure, and grading the Sylvian fissure operculization at 23–25, 27–28 and 31–32 weeks gestation were determined.
Results At 23–25 and 27–28 gestational weeks, POF and CF mean depths were statistically lower in the IMV group. The POF and CF depth distribution had a normal distribution in the control group but displayed a bimodal distribution in the IMV group. IMV with progression of ventricular dilatation showed mean depth ...
