Increased sympathetic outflow in juvenile rats submitted to chronic intermittent hypoxia correlates with enhanced expiratory activity

Chronic intermittent hypoxia (CIH) in rats produces changes in the central regulation of cardiovascular and respiratory systems by unknown mechanisms. We hypothesized that CIH (6% O(2) for 40 s, every 9 min, 8 h day(-1)) for 10 days alters the central respiratory modulation of sympathetic activity. After CIH, awake rats (n = 14) exhibited higher levels of mean arterial pressure than controls (101 +/- 3 versus 89 +/- 3 mmHg, n = 15, P < 0.01). Recordings of phrenic, thoracic sympathetic, cervical vagus and abdominal nerves were performed in the in situ working heart-brainstem preparations of control and CIH juvenile rats. The data obtained in CIH rats revealed that: (i) abdominal (Abd) nerves exhibited an additional burst discharge in late expiration; (ii) thoracic sympathetic nerve activity (tSNA) was greater during late expiration than in controls (52 +/- 5 versus 40 +/- 3%; n = 11, P < 0.05; values expressed according to the maximal activity observed during inspiration and the noise level recorded at the end of each experiment), which was not dependent on peripheral chemoreceptors; (iii) the additional late expiratory activity in the Abd nerve correlated with the increased tSNA; (iv) the enhanced late expiratory activity in the Abd nerve unique to CIH rats was accompanied by reduced post-inspiratory activity in cervical vagus nerve compared to controls. The data indicate that CIH rats present an altered pattern of central sympathetic-respiratory coupling, with increased tSNA that correlates with enhanced late expiratory discharge in the Abd nerve. Thus, CIH alters the coupling between the central respiratory generator and sympathetic networks that may contribute to the induced hypertension in this experimental model.

A novel role for MNTB neuron dendrites in regulating action potential amplitude and cell excitability during repetitive firing

Principal cells of the medial nucleus of the trapezoid body (MNTB) are simple round neurons that receive a large excitatory synapse (the calyx of Held) and many small inhibitory synapses on the soma. Strangely, these neurons also possess one or two short tufted dendrites, whose function is unknown. Here we assess the role of these MNTB cell dendrites using patch-clamp recordings, imaging and immunohistochemistry techniques. Using outside-out patches and immunohistochemistry, we demonstrate the presence of dendritic Na(+) channels. Current-clamp recordings show that tetrodotoxin applied onto dendrites impairs action potential (AP) firing. Using Na(+) imaging, we show that the dendrite may serve to maintain AP amplitudes during high-frequency firing, as Na(+) clearance in dendritic compartments is faster than axonal compartments. Prolonged high-frequency firing can diminish Na(+) gradients in the axon while the dendritic gradient remains closer to resting conditions; therefore, the dendrite can provide additional inward current during prolonged firing. Using electron microscopy, we demonstrate that there are small excitatory synaptic boutons on dendrites. Multi-compartment MNTB cell simulations show that, with an active dendrite, dendritic excitatory postsynaptic currents (EPSCs) elicit delayed APs compared with calyceal EPSCs. Together with high- and low-threshold voltage-gated K(+) currents, we suggest that the function of the MNTB dendrite is to improve high-fidelity firing, and our modelling results indicate that an active dendrite could contribute to a `dual` firing mode for MNTB cells (an instantaneous response to calyceal inputs and a delayed response to non-calyceal dendritic excitatory postsynaptic potentials).

Isolation and characterization of microsatellite markers from the stingless bee Nannotrigona testaceicornis

Conservation of natural populations and handling of breeding programs would benefit from the availability of molecular markers. Stingless bees are one of the most important pollinators in several ecosystems. Thus, seventeen microsatellite markers were developed from an enriched genomic library of Nannotrigona testaceicornis. They were characterized using 50 samples. The expected and observed heterozygosities ranged from 0.59 to 0.89 and from 0.39 to 0.79, respectively. These markers will contribute to advance researches on the genetic conservation, characterization and preservation of the Brazilian native bees.

Association study of an epidermal growth factor gene functional polymorphism with the risk and prognosis of gliomas in Brazil

Epidermal growth factor (EGF) plays an important role in cancer. A functional single nucleotide polymorphism (SNP) in the 5`-untranslated region of the EGF gene (+61 A>G) may influence its expression and contribute to cancer predisposition and aggressiveness. Aiming to investigate the role of EGF +61 A>G in the susceptibility to glioma and its prognosis, we performed a case-control study with 165 patients and 200 healthy controls from Brazil. Comparisons of genotype distributions and allele frequencies did not reveal any significant differences between the groups. The mean overall survival was 9.2 months for A/A, 8.2 months for A/G, and 7.7 months for GIG. When survival curves were plotted we found that the +61G allele is associated with poor overall survival (p=0.023) but not with disease-free survival (p=0.527). Our data suggest that, although there is no association between the EGF +61 A>G genotype and glioma susceptibility, this SNP is associated with shorter overall survival of glioma patients in the Brazilian population. Nevertheless, future studies utilizing a larger series are essential for a definitive conclusion. (Int J Biol Markers 2009; 24: 277-81)

Basal levels of DNA damage detected by micronuclei and comet assays in untreated breast cancer patients and healthy women

Breast cancer is the second most frequent type of cancer worldwide and is the most common malignant disease among women. Risk factors for breast cancer include early menarche, late menopause, hormonal therapies, exposure to environmental pollutants, smoking and alcohol use. However, increased or prolonged exposure to estrogen is the most important risk factor. It has been suggested that accumulation of DNA damage may contribute to breast carcinogenesis. Epidemiological studies suggest that cytogenetic biomarkers such as micronuclei in peripheral blood lymphocytes may predict cancer risk because they indicate genomic instability in target tissues. The objective of the present study was to evaluate the frequencies of micronuclei and the extent of DNA damage detected by comet assay in peripheral blood lymphocytes of untreated breast cancer patients and healthy women. The study was conducted using peripheral blood lymphocytes from 45 women diagnosed for Ductal ""in situ"" or invasive breast carcinoma and 85 healthy control women. Micronuclei and comet assays were performed to detect spontaneous DNA damage. The results showed that micronuclei frequencies and tail intensity, detected by comet assay, were significantly higher in the breast cancer group than in controls. The levels of DNA damage were similar in smokers and non-smokers, and aging did not influence the frequencies of micronuclei or tail intensity values observed in either group. In conclusion, the present work demonstrates higher levels of DNA damage in untreated breast cancer patients than in healthy women.

TRPV1 Expression on Peritoneal Endometriosis Foci is Associated With Chronic Pelvic Pain

Objective: To investigate the expression of capsaicin receptor (transient receptor potential vanilloid type 1 [TRPV1]) in the peritoneal endometriosis foci of women with and without chronic pelvic pain (CPP). Methods: A case-control study was conducted on 49 women with endometriosis who underwent laparoscopy, 28 of whom had CPP and 21 without CPP. Samples from peritoneum of the rectouterine excavation (2 cm(2)) were obtained by laparoscopy, fixed in 4% formaldehyde, and underwent immunohistochemistry analysis using rabbit anti-TRPV1 (1:400) polyclonal antibody. Results: Image analysis revealed that the immunoreactivity for TRPV1 was more frequent in specimens (endometriosis foci) from women with CPP (n = 15 of 28, 53.6%), compared to samples from the endometriosis foci of women without CPP (n = 6 of 21, 28.6%; P = .04). There was no correlation with duration, intensity of pain, or stage of the disease (endometriosis). Discussion: The present study shows that TRPV1 expression in peritoneal endometriosis foci is related to CPP in women. However, this association is not related to the endometriosis stage. In view of the immunoreactivity for TRPV1 observed here, we believe that some endometriotic lesions may provide a scenario for TRPV1 to be tonically active and this activity may contribute to the underlying pathology of CPP.

Climacteric, physically active women ingesting their routine diet oxidize more carbohydrates than lipids

Objective To investigate the influence of a routine Brazilian diet on the rate of oxidation of energy substrates in climacteric, obese women, who came to the outpatient clinic of the Hospital of the School of Medicine of Ribeirao Preto (HCFMRP-USP). Methods Subjects were recruited from outpatients at the Climacteric Clinic of the HCFMRP-USP, who were aged between 39 and 65 years and who voluntarily agreed to participate in this study. They were submitted to anthropometric measurements and indirect calorimetry for resting energy expenditure and substrate oxidation rate determination. Results The carbohydrate oxidation in the group of climacteric, obese women showed a significant positive correlation between energy consumption at rest and ingestion of carbohydrates (in grams); the subjects` rate of lipid intake showed a significant negative correlation with their body mass index, waist circumference, and daily total caloric intake. Conclusion Carbohydrate intake and carbohydrate oxidation rate may contribute to weight gain in climacteric women.

Motor development curve from 0 to 12 months in infants born preterm

Aim: To trace a reference curve for motor development from birth up to 12 months of corrected chronological age in infants born preterm and low birth weight. Methods: This is a cross-sectional study with a sample of 308 preterm infants (53% boys) weighing < 2500 g at birth. The Alberta Infant Motor Scale (AIMS) was used for motor development assessment. Results: Comparing the motor performance of preterm infants with infants from a standardized sample on the AIMS, it was found that, except for the age group of the newborn, preterm infants showed lower motor development scores in comparison with the AIMS normative sample in all age groups between 1 and 12 months. The curve of motor development showed a continuous increase in the number of motor skills of preterm infants during their first 12 months of age. However, the average of motor acquisitions of preterm infants showed a nonlinear pattern with a standard indicator of stabilization between 8 and 10 months of age. Conclusion: Preterm infants, 1-12 months of age, showed motor development AIMS scores lower than the standards established in the normative sample. The findings may contribute as norm-reference for assessing the motor development of preterm infants in follow-up programmes in developing countries.

Matrix metalloproteinase-9 genotypes and haplotypes are associated with multiple sclerosis and with the degree of disability of the disease

Multiple sclerosis (MS) is an autoimmune disease causing severe neurological disability. This study was carried out in order to determine whether the MMP-9 C(-1562)T and (CA)(13-25) polymorphisms are associated with MS. A total of 165 patients (92 whites/73 mulattos) and 191 controls (96 whites/95 mulattos) were enrolled in the study. While no difference in C(-1562)T polymorphism was observed between MS and healthy subjects, (CA)(n) genotypes and alleles were associated with MS. Moreover, the haplotypes are not associated with MS but seem to be relevant to the clinical status of MS. Thus the (CA)(n) polymorphism may contribute to MS susceptibility, but C(-1562)T and (CA)(n) haplotypes may modulate disease severity. (c) 2009 Elsevier B.V. All rights reserved.

Polymorphisms at GLUT1 Gene Are Not Associated With the Development of TSP/HAM in Brazilian HTLV-1 Infected Individuals and the Discovery of a New Polymorphism at GLUT1 Gene

The development of HTLV-1 associated clinical manifestations, such as TSP/HAM and ATLL, occur in 2-4% of the infected population and it is still unclear why this infection remains asymptomatic in most infected carriers. Recently, it has been demonstrated that HTLV uses the Glucose transporter type 1 (GLUT1) to infect T-CD4(+) lymphocytes and that single nucleotide polymorphisms (SNP) in the GLUT1 gene are associated with diabetic nephropathy in patients with diabetes mellitus in different populations. These polymorphisms could contribute to a higher GLUT1 protein expression on cellular membrane, facilitating the entry of HTLV and its transmission cell by cell. This could result in a higher provirus load and consequently in the development of TSP/HAM. To evaluate the role of GLUT1 gene polymorphisms in the development of TSP/HAM in HTLV-1 infected individuals, the g.22999G > T, g.15339T > C and c.-2841A > T sites were analyzed by PCR/RFLP or sequencing in 244 infected individuals and 102 normal controls. The proviral load of the HTLV-1 infected patients was also analyzed using Real Time Quantitative PCR. Genotypic and allelic frequencies of the three sites did not differ significantly between controls and HTLV-1 infected individuals. There was no difference in genotypic and allelic distributions among patients as to the presence or absence of HTLV-1 associated clinic manifestations. As regards the quantification of the provirus load, we observed a significant reduction in the asymptomatic individuals compared with the oligosymptomatic and TSP/HAM individuals. These results suggest that g.22999G > T, g.15339T > C, and c.-2841A > T SNP do not contribute to HTLV-1 infection nor to the genetic susceptibility of TSP/HAM in Brazilian HTLV-1 infected individuals. J. Med. Virol. 81:552557, 2009. (C) 2009 Wiley-Liss, Inc.

Distinct Effects of Delta 9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing

Context: Cannabis use can both increase and reduce anxiety in humans. The neurophysiological substrates of these effects are unknown. Objective: To investigate the effects of 2 main psycho-active constituents of Cannabis sativa (Delta 9-tetrahydrocannabinol [Delta 9-THC] and cannabidiol [CBD]) on regional brain function during emotional processing. Design: Subjects were studied on 3 separate occasions using an event-related functional magnetic resonance imaging paradigm while viewing faces that implicitly elicited different levels of anxiety. Each scanning session was preceded by the ingestion of either 10 mg of Delta 9-THC, 600 mg of CBD, or a placebo in a double-blind, randomized, placebo-controlled design. Participants: Fifteen healthy, English-native, right-handed men who had used cannabis 15 times or less in their life. Main Outcome Measures: Regional brain activation (blood oxygenation level-dependent response), electrodermal activity (skin conductance response [SCR]), and objective and subjective ratings of anxiety. Results: Delta 9-Tetrahydrocannabinol increased anxiety, as well as levels of intoxication, sedation, and psychotic symptoms, whereas there was a trend for a reduction in anxiety following administration of CBD. The number of SCR fluctuations during the processing of intensely fearful faces increased following administration of Delta 9-THC but decreased following administration of CBD. Cannabidiol attenuated the blood oxygenation level dependent signal in the amygdala and the anterior and posterior cingulate cortex while subjects were processing intensely fearful faces, and its suppression of the amygdalar and anterior cingulate responses was correlated with the concurrent reduction in SCR fluctuations. Delta 9-Tetrahydrocannabinol mainly modulated activation in frontal and parietal areas. Conclusions: Delta 9-Tetrahydrocannabinol and CBD had clearly distinct effects on the neural, electrodermal, and symptomatic response to fearful faces. The effects of CBD on activation in limbic and paralimbic regions may contribute to its ability to reduce autonomic arousal and subjective anxiety, whereas the anxiogenic effects of Delta 9-THC may be related to effects in other brain regions.

Modulation of Auditory and Visual Processing by Delta-9-Tetrahydrocannabinol and Cannabidiol: an fMRI Study

Although the effects of cannabis on perception are well documented, little is known about their neural basis or how these may contribute to the formation of psychotic symptoms. We used functional magnetic resonance imaging (fMRI) to assess the effects of Delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) during visual and auditory processing in healthy volunteers. In total, 14 healthy volunteers were scanned on three occasions. Identical 10mg THC, 600mg CBD, and placebo capsules were allocated in a balanced double-blinded pseudo-randomized crossover design. Plasma levels of each substance, physiological parameters, and measures of psychopathology were taken at baseline and at regular intervals following ingestion of substances. Volunteers listened passively to words read and viewed a radial visual checkerboard in alternating blocks during fMRI scanning. Administration of THC was associated with increases in anxiety, intoxication, and positive psychotic symptoms, whereas CBD had no significant symptomatic effects. THC decreased activation relative to placebo in bilateral temporal cortices during auditory processing, and increased and decreased activation in different visual areas during visual processing. CBD was associated with activation in right temporal cortex during auditory processing, and when contrasted, THC and CBD had opposite effects in the right posterior superior temporal gyrus, the right-sided homolog to Wernicke`s area. Moreover, the attenuation of activation in this area (maximum 61, -15, -2) by THC during auditory processing was correlated with its acute effect on psychotic symptoms. Single doses of THC and CBD differently modulate brain function in areas that process auditory and visual stimuli and relate to induced psychotic symptoms. Neuropsychopharmacology (2011) 36, 1340-1348; doi:10.1038/npp.2011.17; published online 16 March 2011

The aging lacrimal gland: Changes in structure and function

The afferent nerves of the cornea and conjunctiva, efferent nerves of the lacrimal gland, and the lacrimal gland are a functional unit that works cooperatively to produce the aqueous component of tears. A decrease in the lacrimal gland secretory function can lead to dry eye disease. Because aging is a risk factor for dry eye disease, study of the changes in the function of the lacrimal gland functional unit with age is important for developing treatments to prevent dry eye disease. No one mechanism is known to induce the changes that occur with aging, although multiple different mechanisms have been associated with aging. These fall into two theoretical categories: programmed theories of aging (immunological, genetic, apoptotic, and neuroendocrine) and error theories of aging (protein alteration, somatic mutation, etc). Lacrimal glands undergo structural and functional alteration with increasing age. In mouse models of aging, it has been shown that neural stimulation of protein secretion is an early target of aging, accompanied by an increase in mast cells and lipofuscin accumulation. Hyperglycemia and increased lymphocytic infiltration can contribute to this loss of function at older ages. These findings suggest that an increase in oxidative stress may play a role in the loss of lacrimal gland function with age. For the afferent and efferent neural components of the lacrimal gland functional unit, immune or inflammatory mediated decrease in nerve function could contribute to loss of lacrimal gland secretion with age. More research in this area is critically needed.

Can eccentric arterial plaques alone cause flow stagnation points and favour thrombus incorporation?

We have used an experimental model of aorta stenosis, with a Plexiglas plug, simulating a stable atheromatous plaque that promotes local turbulence and thrombosis. With animal survival of more than 24 h, we followed the partial fibrinolysis of the thrombus as well as its posterior organization and incorporation to the arterial wall as a neointima for up to 30 days. The mushroom plug form permitted the development of recirculation and stasis areas around it, favouring this evolution. Despite noted limitations, this study demonstrates that thrombus incorporation can contribute to plaque extension, as it can promote recirculation and stasis areas.

Osteopontin expression according to molecular profile of invasive breast cancer: a clinicopathological and immunohistochemical study

Osteopontin (OPN) is a secreted, calcium-binding phosphorylated glycoprotein involved in several physiological and pathological events such as angiogenesis, apoptosis, inflammation, wound healing, vascular remodeling, calcification of mineralized tissues, and induction of cell proteases. There is growing interest in the role of OPN in breast cancer. In an attempt to obtain new insight into the pathogenesis of OPN-associated breast carcinomas, an immunohistochemical panel with 17 primary antibodies including cytokeratins and key regulators of the cell cycle was performed in 100 formalin-fixed paraffin-embedded samples of invasive breast carcinomas. OPN was expressed in 65% of tumors and was negatively correlated with estrogen (p=0.0350) and progesterone (p=0.0069) receptors, but not with the other markers and clinicopathological features evaluated including age, menstrual status, pathological grading, tumor size, and metastasis. There was no correlation between OPN expression and carcinomas of the basal-like phenotype (p=0.1615); however, OPN correlated positively with c-erbB-2 status (p=0.0286) and negatively with carcinomas of the luminal subtype (p=0.0353). It is well known that carcinomas overexpressing c-erbB-2 protein have a worse prognosis than luminal tumors. Here, we hypothesize that the differential expression of OPN in the first subtype of carcinomas may contribute to their more aggressive behavior. (Int J Biol Markers 2008; 23: 154-60)