Haemal nodes are capsulated, lymphoid organs with haemal circulation. Their parenchyma is distributed in primary and secondary lymphatic nodes in the cortical and medullar zones. In these zones the lymphatic tissue may adopt a cord-like shape and it is composed by plasma cell, macrophages and B and T lymphocytes. Blood circulates through the sinuses situated underneath the capsule, around the trabeculae and in the marrow.

Automatic image processing of transmission electron microscopy images (TEM) is a utopia often pursued, considering the thousands of images necessary to ensure a high resolution 3D reconstruction of virus particles or other macromolecular machines.

Diabetes is a major health problem with an alarming increasing prevalence, and is the most frequent cause of neuropathy worldwide. Neuropathy affects 50–60% of diabetic patients, being a major life-quality impairment for a quarter of these patients. Diabetic neuropathic pain (DNP) is characterized by spontaneous pain, mechanical hyperalgesia and tactile allodynia and is accompanied by functional and neurochemical changes at the peripheral nerves, spinal cord and supraspinal pain control areas. Regarding the effects of diabetic neuropathy in the central somatossensory system, it was shown that streptozotocin (STZ)-diabetic rats present spontaneous hyperactivity and hyperexcitability of spinal nociceptive neurons, which may be subserving the exacerbated pain responses. The spinal functional changes and pain may be due to increased peripheral input(2), changes in spinal nociceptive modulatory mechanisms and altered supraspinal descending pain modulation. Noradrenergic descending pain modulation seems to be impaired since STZ-diabetic rats present decreased numbers of noradrenergic neurons at the A5 and A7 pontine cell groups, along with lower levels of noradrenaline at the spinal cord and higher behavioral responses to pain. This is consistent with the strong noradrenergic projection from A5 and A7 neurons to the spinal dorsal horn and the modulation of nociceptive transmission by local release of noradrenaline. The mechanisms underlying the decrease in noradrenergic neurons in the brainstem during diabetes remain unclear. Our recent findings that diabetes induces oxidative stress damage in neurons from those areas, lead us to hypothesize that it may contribute to their loss. Thereafter, with the present study we aimed to evaluate the effects of Epigallocathechin Gallate (EGCG), a potent antioxidant present in green tea, on spinal noradrenaline levels, on A5 and A7 noradrenergic neurons and on behavioral pain responses of STZ-diabetic rats.

Cardiovascular diseases (CVD) constitute a leading cause of death in the aged population. Regular intake of hyperlipidic diet and obesity can induce endothelial dysfunction that precedes the onset of atherosclerosis and CVD. High-fat diet regular consumption leads to structural modifications in heart tissue, and changes in the expression of angiogenic factors and their specific receptors. Hence, we aimed to characterize the expression pattern of vascular endothelial growth factor (VEGF) and its membrane receptor VEGFR 2 in young and aged rat hearts under high-fat diet and energy restriction.

Diabetes type 1 is a very common chronic disease that frequently initiates in youth. Patients suffering from this disease have an increased risk of developing complications such as cardiovascular disease or erectile dysfunction. This is partially due to oxidative stress in affected cells, induced by the increasing production of reactive oxygen species (ROS) that, in addition to oxidative macromolecular damage, inactivate nitric oxide (NO). This condition strongly affects blood vessels of corpus cavernosum (CC), decreasing erectile capability of penis. Thus, we hypothesise that treatment with antioxidants present in the green tea in the initial phase of diabetes type 1 may protect CC from structural and molecular changes induced by oxidative damage. In support of this hypothesis a previous study of our group demonstrated that green tea long-term ingestion led to decrease in lipid perivascular deposition and vascular endothelial growth factor (VEGF) and its receptor VEGFR 2 expression in CC of aged rats. VEGF is the main angiogenic factor in tissues that induces proliferation and survival of endothelial cells after binding to VEGFR2. In fact, VEGF/VEGFR2 system is involved in both physiological and pathological angiogenic processes, and most of the molecular changes observed in aged CC derive from oxidative stress coupled to impairment of angiogenic mechanisms. VEGF also engage VEGFR1, nevertheless the exact role of VEGFR1 activation in cavernous tissue is not yet clarified.

The use of transgenic plants for the large scale production of recombinant proteins with commercial and therapeutic value has emerged as an alternative to conventional platforms. Plant based systems, including whole plants and plant cell cultures offer many advantages particularly regarding safety and cost effectiveness. In our laboratory we have been using the model plant Medicago truncatula as a system to express recombinant proteins with a variety of applications.

Calculi in salivary glands and ducts (sialoliths) can be found in about 1% of the general population. Typically sialolithiasis causes long-term obstruction of salivary secretions, leading to atrophy of the gland with concomitant ceasing of the secretory function and ultimately fibrosis. Although some theories have been put forward regarding the etiology and pathogenesis of salivary calculi, the exact nucleation and growth mechanisms remain elusive. An exhaustive characterization of salivary calculi and systematic evaluation of the existing etiologic theories is therefore required.

Spermatogenesis is a complex process of cell proliferation, meiosis and differentiation. In order to determine the genetic mechanisms that control this process we need to develop adequate methodologies for the purification of stage-specific germ cells. In this study we aim to evaluate four markers (c-kit, oct-4, Integrin α6 and Integrin β1), used to isolate spermatogonial stem cells in mammals, as possible markers to isolate/sort testicular adult stem and progenitor cells in humans.

Several forest species are severely affected by Phytophthora cinnamomi. The contribution of this oomycete to forest decline and dieback has been broadly reported. In particular, it is consensual that it is the causal agent of ink disease in Castanea sativa. It has been associated with the severe decline of Quercus species, namely the Q. suber and Q. ilex dieback in Portugal and Spain, and has been responsible for the infection of numerous native species and crops. This pathogen persists in the soil or on plant material in the form of chlamydospores allowing the infection of living root tissues when environmental conditions are favorable.

Vascular aging is associated with progressive deterioration of vascular homeostasis, a phenomenon that affects organs in different extent. The small vessels of the corpus cavernosum (CC) are very sensitive to functional and structural changes, and particularly susceptible to age-related modifications and atherosclerotic occlusion. Penile erection is a vascular event largely regulated by the relaxation of arterial and corporal smooth muscle (SM) that directly relates to its content and integrity, and inversely to that of connective tissue (CT). Corpora expansion also depends on nitric oxide (NO) bioavailability, a molecule with recognized vasodilatory and antifibrotic properties. Thus, endothelial dysfunction mainly provoked by NO loss is currently considered equivalent to vasculogenic erectile dysfunction (ED), and the earliest clinical manifestation of atherosclerosis and systemic vascular disease. Collagen deposition in tissues, such as CC and heart, strongly compromises their function and is one of the causes of ED and cardiac failure, respectively, but as far as we know no correlation between peripheral and cardiac endothelial dysfunction has been already demonstrated. Therefore, we aimed to evaluate morphological structure and collagen deposition in rat CC, myocardium and tail artery during aging, under high-fat diet (HFD) consumption (a strong contributor to endothelial dysfunction onset), and energy restriction.

Cord formation in Mycobacterium tuberculosis has been traditionally related to virulence since avirulent M. tuberculosis strains do not form cords. These structures consist of bacilli aligned in parallel, end to end, and side to side, along the long axis of the cord. However, similar structures were recently found in non-pathogenic and in opportunistic Mycobacterium species such as M. abscessus, M. chubuense, M. gilvum, M. haemophilum, M. marinum, M. obuense, M. parafortuitum, and M. vaccae. Although the visualization of cords has been traditionally achieved using Ziehl-Neelsen staining, the resolution of light microscopy does not allow to distinguish among cords, pseudocords, clumps or loose aggregates. Nevertheless, the observation of these formations at high resolution is crucial for two essential applications. Firstly, to identify the unknown mycobacterial components responsible for cording formation, an important step to understand virulence. Secondly, to demonstrate that cording is not specific of M. tuberculosis, since many clinical mycobacteriology laboratories base the tuberculosis diagnostic on the observation of cording morphology, and may mistakenly identify non-tuberculous mycobacteria as M. tuberculosis. Thus, patients would be exposed to an ineffective drug regimen with many adverse side effects. Here, we focused on sample treatment in order to certainly observe cords by using scanning electron microscopy (SEM).

Alzheimer´s disease (AD) is characterized by extensive neuronal loss in brain areas related to memory and cognitive functions. Central to the neurodegenerative process is a peptide termed Abeta. The latter is the main component of senile plaques, one of the histopathological hallmarks of AD, and derives from proteolytic processing of the Alzheimer´s amyloid precursor protein (APP). Among the alterations induced by Abeta is increased cellular oxidative stress, imbalanced protein phosphorylation and cytoskeletal abnormalities, all factors that contribute to neuronal death.

In recent years great importance has been given to the adverse effects of particulate matter (PM) in health, and several epidemiological studies correlating the airborne particles with pulmonary injury have been carried out. The adverse effect of short- and long-term expositions to PM can, indeed, cause a variety of effects, from minor effects on the respiratory system to serious oncogenic effects that can lead to precocious death and are considered one of the top environmental public health concerns. Some cytogenetic techniques, as micronucleus assay, allow to detect chromosome breakage and loss by measuring the formation of micronuclei and proved to be a good tool in the evaluation of genotoxic damage induced by PM. Thus genotoxic effects can be evaluated by micronucleus test in order to identify a gradient of potential exposure and to assess environmental monitoring. However, cross investigations involving biomarkers of genotoxicity and electron microscopy PM-induced tracheal and lung damages in natural populations are not common.

Helicobacter pylori is a human pathogen involved in gastritis and gastric cancer whose mode of transmission remains unknown. Association of H. pylori with humans is thought to date from remote antiquity and the bacterium has apparently evolved together with the human host. A few studies have shown the presence of H. pylori in aquatic environments, which might provide a route of transmission of the bacteria to humans. A recent study has also disclosed the association of the bacteria with Acantamoeba castellanii. Amoeba are known to harbor and promote the persistence of several human pathogens in the environment, representing a significant source of contamination in community and hospital acquired infections.

Heterotermic vertebrates are hosts of a variety of iridoviruses, many with recognized economical importance for aquaculture and with a role in the decline of amphibian populations, and others with no known disease associations. These include members of the Lymphocystisvirus, Magalocystisvirus and Ranavirus genera.

Amoebae graze on bacteria from the environment. In some cases, bacteria acquire resistance to the destructive action of amoebae and survive inside the host. The resistance of microorganisms to amoebae is often accompanied by resistance to the physiologically related human macrophage and displays increased pathogenic potential to humans. The association of bacteria with amoebae, that are ubiquitous in the environment, protects the bacteria from common disinfection measures. This leads to the creation of reservoirs of pathogenic microorganisms that are difficult to eradicate. This process occurs widely in the environment, but is of special concern in hospitals, where many established and emerging pathogens involved in nosocomial disease, such as Legionella pneumophila, are increasingly being identified in association with amoebae. One particularly important amoeba-associated microorganism (AAM) is the newly recognized giant mimivirus, a member of the Nucleo-Cytoplasmic Large Deoxyribovirus (NCLDV) group. The virus has been isolated from hospital sources in France and, together with other members of the NCLDV group, is known from metagenomic studies to be widespread in the Oceans, representing one of the main groups of marine viruses. Our project aims to detect amoeba and potentially pathogenic AAMs with particular relevance to the NCLDVs in the environment and in hospital facilities. In the present work we have developed methods for detection, isolation and in vitro culture of amoebae from several environmental sources including hospital dust, sea water and estuarine sediments.

Superoxide dismutases (SODs) are a class of antioxidant enzymes which catalyze the dismutation of superoxide into oxygen and hydrogen peroxide, therefore controlling cellular levels of Reactive Oxygen Species (ROS). In the mature pollen grains of the olive tree, the presence of several forms of CuZn-SOD and the cytosolic localization of the enzyme have been described. The present study was aimed to elucidate the adaptation of the oxidative metabolism to the changing conditions occurring during the course of olive pollen formation, hydration and pollen tube emergence and growth. We used a polyclonal antibody (raised against a KLH-linked synthetic peptide including a consensus sequence for CuZn-SODs in olive pollen) in immunocytochemical experiments carried out by Fluorescence (FM) and Transmission Electron Microcopy (TEM).

The epididymis is a long convoluted tubule that serves as a conduit for the transport of spermatozoa from the testis to the vas deferens and is the site where spermatozoa mature and acquire their functions of progressive motility and fertility. Unfortunately, very little is known about the human epididymis and its role in sperm maturation owing to the lack of studies conducted on normal human tissue. The role of epididymal luminal microenvironment and the mechanisms that epididymis uses to carry out its functions remain unsolved.

Metabolic Syndrome (MS) definition is based on a cluster of metabolic risk factors that identifies subjects at high risk for forthcoming type 2 diabetes mellitus and atherosclerotic cardiovascular diseases (CVD). Although the exact aetiology of the MS still remains unclear, it is known to involve complex interactions between genetic, metabolic and environmental factors, with diet and oxidative stress playing important roles. Regular increased fructose consumption has been associated to some metabolic adverse changes observed in the MS and, thus, fructose-fed is considered a suitable animal model of diet-induced MS. On the other hand, calcium, magnesium and potassium, generally deficient in MS-inducing diets, and abundant in natural mineral-rich waters, have been proposed protective against the MS. Although their exact effects are not yet fully clarified, natural mineral-rich waters present some antioxidant properties that exert protection against reactive oxygen species that are chief contributors to the increase of CVD risk, considering their reactivity to nitric oxide (NO). Such waters also improve some MS metabolic risk factors. Degradation of NO seriously compromises the vasodilatation mechanism leading to endothelial dysfunction, which always precedes atherosclerosis — the main contributor to CVD and erectile dysfunction. Penis erection is a vascular process that strongly depends on NO-induced smooth muscle relaxation. Moreover, NO mediates indirectly the vascular endothelial growth factor (VEGF)-induced angiogenesis, which is fundamental to maintain endothelium integrity in the cavernous tissue. VEGF binds specifically to VEGF tyrosine kinase membrane receptors (VEGFR1 and VEGFR2), and crosstalk in vivo with other angiogenic factors such as angiopoietins that compete for binding to the endothelial-specific Tie2 receptor. Previous work from our group demonstrated that long-term consumption of antioxidant-rich beverages modifies the expression of VEGF, Ang1, Ang2 and their receptors VEGFR1, VEGFR2 and Tie2 in the cavernous tissue of the rat, preventing atherosclerosis progression.

Particles of anthropogenic and biological origin, minerals and gaseous elements are the major constituents of the aerosol. Pollen is a biological component of the aerosol, found in suspension with other pollutants. In recent years, research has been conducted on the crossed effects between non-biological and biological pollutants on allergy worsening in susceptible individuals or on the development of symptoms in non-symptomatic ones. Platanus spp pollen is abundantly present in the atmosphere of Porto in early spring and is known to promote allergic respiratory symptoms. The aim of this study was to characterize possible alterations of the main elements present on the Platanus spp. pollen wall under different atmospheric conditions in the coastal city of Porto, Portugal, using EPMA.