Página 12 dos resultados de 1996 itens digitais encontrados em 0.006 segundos

Avaliação in vitro do potencial erosivo de bebidas isotônicas

Cavalcanti,Alessandro Leite; Xavier,Alidianne Fábia Cabral; Souto,Rafaella Queiroga; Oliveira,Mariana da Costa; Santos,Jalber Almeida dos; Vieira,Fernando Fernandes
Fonte: Sociedade Brasileira de Medicina do Exercício e do Esporte Publicador: Sociedade Brasileira de Medicina do Exercício e do Esporte
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 PT
Relevância na Pesquisa
17.17%
Isotônico é uma bebida destinada a reidratar, bem como repor eletrólitos, carboidratos e outros nutrientes. O objetivo deste estudo in vitro foi avaliar o pH endógeno, a acidez total titulável (ATT) e o teor de sólidos solúveis totais (SST) de nove bebidas isotônicas à temperatura ambiente (±23ºC) e após resfriamento (±9ºC). A avaliação do pH foi feita por potenciometria e a capacidade tampão foi realizada por meio da diluição de cada uma das substâncias. Incrementos de 0,1NKOH foram adicionados até que se atingisse a neutralidade. As leituras dos SST foram feitas por refratometria usando o refratômetro de Abbé. As médias do pH variaram de 2,03 (Gatorade Tangerina®) a 2,93 (Marathon Limão®) e todos as bebidas mostraram pH abaixo do valor crítico de 5,5. As médias da ATT variaram de 0,10 para o Marathon Limão® a 0,32 para o Gatorade Tangerina®. O Gatorade Tangerina® apresentou o menor valor de SST (6,33%) e o Marathon Guaraná e Açaí® mostrou o maior valor de SST (12,50%). Foram observadas diferenças estatisticamente significantes entre as temperaturas para o pH (G3, G4, G5, G6 e G8), para os SST (G2, G3, G6 e G9) e para a ATT (G2, G3 e G5). Ao se comparar os grupos 1 e 3 (Marathon Guaraná Açaí® x Gatorate Guaraná Açaí®) observou-se diferença estatisticamente significante entre em relação ao pH para a temperatura ambiente...

Low-frequency physical variations in the coastal zone of Ubatuba, northern coast of São Paulo State, Brazil

Valentim,Samuel Soares; Bernardes,Marcos Eduardo Cordeiro; Dottori,Marcelo; Cortezi,Matheus
Fonte: Universidade de São Paulo, Instituto Oceanográfico Publicador: Universidade de São Paulo, Instituto Oceanográfico
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2013 EN
Relevância na Pesquisa
17.17%
Sea level (SL), wind, air temperature (AT) and sea surface temperature (SST) variations in the coastal region of Ubatuba, northern coast of São Paulo, are assessed. A Lanczos-square cosine filter, with a 40-hour window, was applied over the SL time series between 1978 and 2000, except for the period comprising 1984 to 1986. In order to study subtidal effects on mean sea level (MSL), SL numerical filtering indicated that there was a virtually complete removal of semidiurnal and diurnal astronomical tidal components over the period of study. Results indicated an average raw SL rise of 2.3 mm/year, whereas average filtered MSL was of the order of 0.7 mm/year. Despite the overall positive MSL trend, the lunar nodal cycle of 18.6 years seemed to be the explanation for the SL series pattern. Correlations between MSL and parallel wind had a maximum correlation coefficient around 0.6, with 99% statistical confidence, while MSL and perpendicular wind correlations were not statistically significant. These results may be explained by Ekman dynamics. Data records of AT and SST between 1990 and 2003 showed positive trends for both variables. During this period, AT rose about 0.087 ºC /year for the raw series and 0.085 ºC /year for the monthly time series...

Effects of GnRH treatment on scrotal surface temperatures in bulls.

Gábor, G; Kastelic, J P; Cook, R B; Sasser, R G; Brito, L F; Csik, J V; Coulter, G H; Györkös, I
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/2001 EN
Relevância na Pesquisa
17.17%
Two experiments were conducted to characterize scrotal surface temperature (SST) in bulls treated with gonadotropin releasing hormone (GnRH). In Experiment 1, Angus bulls (n = 10, 18 mo, 597 kg) were given GnRH (400 ng/kg) or saline, IV. Bottom SST increased approximately 1.7 degrees C (P < 0.005) over time (0 to 90 min) at an ambient temperature of 5 degrees C. However, there was no significant effect of GnRH treatment and temperature increases were attributed to stress. When the experiment was repeated at an ambient temperature of 25 degrees C, SST was elevated prior to treatment, with no subsequent significant increase. Experiment 2 was conducted with Charolais bulls (n = 6, 12-14 mo, 517 kg) with an emphasis on minimizing stress. Bottom SST increased approximately 2 degrees C (P < 0.05) between 0 and 45 min after GnRH treatment, supporting the hypothesis that GnRH treatment increases SST in bulls. In conclusion, it was apparent that stress, high ambient temperatures, and GnRH treatment can all increase SST in bulls.

Role of endogenous somatostatin in postprandial hypersecretion of neurotensin in patients after gastrectomy.

Sakamoto, T; Miyata, M; Izukura, M; Tanaka, Y; Iwase, K; Imabun, S; Matsuda, H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1997 EN
Relevância na Pesquisa
17.17%
OBJECTIVE: The purpose of this report is to elucidate the mechanism of the hypersecretion of neurotensin (NT) after gastrectomy. SUMMARY BACKGROUND DATA: NT secretion induced by fat ingestion is increased after pancreatoduodenectomy or distal gastrectomy. The hypersecretion of NT in the patients undergoing resection of the upper gastrointestinal tract is suppressed by an exogenous somatostatin (SST) analog. METHODS: We observed simultaneously the secretion of NT and SST in the same patients before and after gastrectomy (n = 7). We also observed the secretion of these hormones induced by intraduodenal (ID) fat infusion in the normal volunteers (n = 6). RESULTS: The response of plasma NT to fat ingestion was significantly increased after gastrectomy compared with that before gastrectomy. The response of plasma SST after gastrectomy was significantly suppressed. The response of plasma NT and SST after ID fat infusion in the normal volunteers was similar to the gastrectomized state. CONCLUSION: Diminution of SST secretion, probably caused by the lack of SST cells in the distal part of the stomach, may play a role in augmenting NT secretion after gastrectomy.

Inhibitory effects of malotilate on invasion and metastasis of rat mammary carcinoma cells by modifying the functions of vascular endothelial cells.

Nagayasu, H.; Hamada, J.; Kawano, T.; Konaka, S.; Nakata, D.; Shibata, T.; Arisue, M.; Hosokawa, M.; Takeichi, N.; Moriuchi, T.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em /05/1998 EN
Relevância na Pesquisa
17.17%
Malotilate (diisopropyl,1,3-dithiol-2-ylidenemalonate, MT) is clinically used as a hepatoprotective agent. Because we noticed that MT induced the differentiation of cultured vascular endothelial cells, we have examined its effects on lung metastasis of the highly metastatic rat mammary carcinoma c-SST-2. MT was orally administered to syngeneic SHR rats from 7 days before or after s.c. inoculation of c-SST-2 cells to the end of the experiments. In the MT-treated rats, pulmonary metastasis was markedly suppressed compared with the non-treated rats. In the rats treated with MT for 19 days after i.v. inoculation of c-SST-2 cells, lung metastasis was also significantly suppressed. An in vitro invasion assay using a rat lung endothelial (RLE) cell monolayer revealed that pretreatment of the RLE cells with MT, but not c-SST-2 cells, significantly reduced the invasion of the RLE monolayer by c-SST-2 cells. An in vitro vascular permeability assay demonstrated that MT prevented the increase in permeability of the RLE monolayer by serum starvation. On the other hand, in vivo and in vitro growth, gelatinase production and adhesion to the RLE cell monolayer of c-SST-2 cells were not affected by MT treatment. These findings suggest that MT suppressed tumour metastasis by intensifying the cell-to-cell contact of endothelial cells...

Effects of a single dose of N-Acetyl-5-methoxytryptamine (Melatonin) and resistance exercise on the growth hormone/IGF-1 axis in young males and females

Nassar, Erika; Mulligan, Chris; Taylor, Lem; Kerksick, Chad; Galbreath, Melyn; Greenwood, Mike; Kreider, Richard; Willoughby, Darryn S
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 23/10/2007 EN
Relevância na Pesquisa
17.17%
Melatonin and resistance exercise alone have been shown to increase the levels of growth hormone (GH). The purpose of this study was to determine the effects of ingestion of a single dose of melatonin and heavy resistance exercise on serum GH, somatostatin (SST), and other hormones of the GH/insulin-like growth factor 1 (IGF-1) axis. Physically active males (n = 30) and females (n = 30) were randomly assigned to ingest either a melatonin supplement at 0.5 mg or 5.0 mg, or 1.0 mg of dextrose placebo. After a baseline blood sample, participants ingested the supplement and underwent blood sampling every 15 min for 60 min, at which point they underwent a single bout of resistance exercise with the leg press for 7 sets of 7 reps at 85% 1-RM. After exercise, participants provided additional blood samples every 15 min for a total of 120 min. Serum free GH, SST, IGF-1, IGFBP-1, and IGFBP-3 were determined with ELISA. Data were evaluated as the peak pre- and post-exercise values subtracted from baseline and the delta values analyzed with separate three-way ANOVA (p < 0.05). In males, when compared to placebo, 5.0 mg melatonin caused GH to increase (p = 0.017) and SST to decrease prior to exercise (p = 0.031), whereas both 0.5 and 5.0 mg melatonin were greater than placebo after exercise (p = 0.045) and less than placebo for SST. No significant differences occurred for IGF-1; however...

Upper Limb Neural Tension and Seated Slump Tests: The False Positive Rate among Healthy Young Adults without Cervical or Lumbar Symptoms

Davis, D. Scott; Anderson, Ila Beth; Carson, Mary Grace; Elkins, Caroline L.; Stuckey, Lindsey B.
Fonte: Journal of Manual & Manipulative Therapy, Inc. Publicador: Journal of Manual & Manipulative Therapy, Inc.
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
Relevância na Pesquisa
17.17%
This study examined the false positive rate of the upper limb neural tension test (ULNTT) and seated slump test (SST) among healthy young adults with no history of cervical, lumbar, or peripheral symptoms. Eighty-four subjects (27 men and 57 women) with a mean age of 22.9 years participated in the investigation. All participants completed a screening questionnaire designed to exclude subjects with a history of cervical or lumbar spine pain or injury, or upper or lower extremity neurological symptoms. The ULNTT and the SST were performed on the left upper and lower extremity of each participant. Of the 84 participants tested, 73 (86.9%) were found to have a positive ULNTT at some point in the available range of elbow extension. Twenty-eight (33.3%) of the 84 subjects had a positive SST at some point in the available range of knee extension. The mean knee extension angle for those subjects with a positive SST was 15.1° with a 95% confidence interval (CI) of 12.3 and 19.7°. The mean elbow extension angle for those with a positive ULNTT was 49.4° with a 95% CI of 44.8 and 54.0°. The number of positive tests for both the ULNTT and the SST was found to be high in this sample of asymptomatic healthy young adults. Based on the results of this investigation...

Tensile properties and fiber alignment of human supraspinatus tendon in the transverse direction demonstrate inhomogeneity, nonlinearity and regional isotropy

Lake, Spencer P.; Miller, Kristin S.; Elliott, Dawn M.; Soslowsky, Louis J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
A recent study (Lake et al. 2009) reported the properties of human supraspinatus tendon (SST) tested along the predominant fiber direction. The SST was found to have a relatively disperse distribution of collagen fibers, which may represent an adaptation to multiaxial loads imposed by the complex loading environment of the rotator cuff. However, the multiaxial mechanical properties of human SST remain unknown. The objective of this study, therefore, was to evaluate the mechanical properties, fiber alignment, change in alignment with applied load, and structure-function relationships of SST in transverse testing. Samples from six SST locations were tested in uniaxial tension with samples oriented transverse to the tendon long-axis. Polarized light imaging was used to quantify collagen fiber alignment and change in alignment under applied load. The mechanical properties of samples taken near the tendon-bone insertion were much greater on the bursal surface compared to the joint surface (e.g., bursal moduli 15–30 times greater than joint; p<0.001). In fact, the transverse moduli values of the bursal samples were very similar to values obtained from samples tested along the tendon long-axis (Lake et al., In press, JOR). This key and unexpected finding suggests planar mechanical isotropy for bursal surface samples near the insertion...

Neuronostatin is co-expressed with somatostatin and mobilizes calcium in cultured rat hypothalamic neurons

Dun, Siok L.; Brailoiu, G. Cristina; Tica, Andrei A.; Yang, Jun; Chang, Jaw K.; Brailoiu, Eugen; Dun, Nae J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
Neuronostatin (NST) is a newly identified peptide of 13-amino acids encoded by the somatostatin (SST) gene. Using a rabbit polyclonal antiserum against the human NST, neuronostatin-immunoreactive (irNST) cells comparable in number and intensity to somatostatin immunoreactive (irSST) cells were detected in the hypothalamic periventricular nucleus. Fewer and/or less intensely labeled irNST cells were noted in other regions such as the hippocampus, cortex, amygdala, and cerebellum. Double-labeling hypothalamic sections with NST- and SST-antiserum revealed an extensive overlapping of irNST and irSST cells in the periventricular nucleus. Pre-absorption of the NST-antiserum with NST (1 µg/ml) but not with SST (1 µg/ml) abrogated irNST and vice versa. The activity of NST on dissociated and cultured hypothalamic neurons was assessed by the Ca2+ imaging method. NST (10, 100, 1000 nM) concentration-dependently elevated intracellular Ca2+ concentrations [Ca2+]i in a population of hypothalamic neurons with two distinct profiles: 1) a fast and transitory increase in [Ca2+]i, and 2) an oscillatory response. Whereas, SST (100 nM) reduced the basal [Ca2+]i in 21 of 61 hypothalamic neurons examined; an increase was not observed in any of the cells. Optical imaging with a slow-responding voltage sensitive dye DiBAC4(3) showed that NST (100 nM) depolarized or hyperpolarized; whereas...

Pattern of Fos expression in the brain induced by selective activation of somatostatin receptor 2 in rats

Goebel, Miriam; Stengel, Andreas; Wang, Lixin; Coskun, Tamer; Alsina-Fernandez, Jorge; Rivier, Jean; Taché, Yvette
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
Central activation of somatostatin (sst) receptors by oligosomatostatin analogs inhibits growth hormone and stress-related rise in catecholamine plasma levels while stimulating grooming, feeding behaviors, gastric transit and acid secretion, which can be mimicked by selective sst2 receptor agonist. To evaluate the pattern of neuronal activation induced by peptide sst receptor agonists, we assessed Fos-expression in rat brain after intracerebroventricular (icv) injection of a newly developed selective sst2 agonist compared to the oligosomatostatin agonist, ODT8-SST, a pan-sst1–5 agonist. Ninety min after injection of vehicle (10µl) or previously established maximal orexigenic dose of peptides (1µg=1nmol/rat), brains were assessed for Fos-immunohistochemistry and doublelabeling. Food and water were removed after injection. The sst2 agonist and ODT8-SST induced a similar Fos distribution pattern except in the arcuate nucleus where only the sst2 agonist increased Fos. Compared to ODT8-SST, the sst2 agonist induced higher Fos-expression by 3.7-fold in the basolateral amygdaloid nucleus, 1.2-fold in the supraoptic nucleus (SON), 1.6-fold in the magnocellular paraventricular hypothalamic nucleus (mPVN), 4.1-fold in the external lateral parabrachial nucleus...

Developmental Origin of preBötzinger Complex Respiratory Neurons

Gray, Paul A.; Hayes, John A.; Ling, Guang Y.; Llona, Isabel; Tupal, Srinivasan; Picardo, Maria Cristina D.; Ross, Sarah E.; Hirata, Tsutomu; Corbin, Joshua G.; Eugenin, Jaime; Del Negro, Christopher A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 03/11/2010 EN
Relevância na Pesquisa
17.17%
A subset of preBötzinger Complex (preBötC) neurokinin 1 receptor (NK1R) and somatostatin peptide (SST) expressing neurons are necessary for breathing in adult rats, in vivo. Their developmental origins and relationship to other preBötC glutamatergic neurons are unknown. Here we show, in mice, that the “core” of preBötC SST+/NK1R+/SST 2a receptor+ (SST2aR) neurons, are derived from Dbx1 expressing progenitors. We also show Dbx1 derived neurons heterogeneously co-express NK1R and SST2aR within and beyond the borders of preBötC. More striking, we find that nearly all non-catecholaminergic glutamatergic neurons of the ventrolateral medulla (VLM) are also Dbx1 derived. PreBötC SST+ neurons are born between E9.5 and E11.5 in the same proportion as non-SST expressing neurons. Additionally, preBötC Dbx1 neurons are respiratory-modulated and show an early inspiratory phase of firing in rhythmically active slice preparations. Loss of Dbx1 eliminates all glutamatergic neurons from the respiratory VLM including preBötC NK1R+/SST+ neurons. Dbx1 mutant mice do not express any spontaneous respiratory behaviors in vivo. Moreover, they do not generate rhythmic inspiratory activity in isolated en bloc preparations even after acidic or serotonergic stimulation. These data indicate preBötC core neurons represent a subset of a larger...

Topography of Somatostatin Gene Expression Relative to Molecular Progenitor Domains during Ontogeny of the Mouse Hypothalamus

Morales-Delgado, Nicanor; Merchan, Paloma; Bardet, Sylvia M.; Ferrán, José L.; Puelles, Luis; Díaz, Carmen
Fonte: Frontiers Research Foundation Publicador: Frontiers Research Foundation
Tipo: Artigo de Revista Científica
Publicado em 28/02/2011 EN
Relevância na Pesquisa
17.17%
The hypothalamus comprises alar, basal, and floor plate developmental compartments. Recent molecular data support a rostrocaudal subdivision into rostral (terminal) and caudal (peduncular) halves. In this context, the distribution of neuronal populations expressing somatostatin (Sst) mRNA was analyzed in the developing mouse hypothalamus, comparing with the expression pattern of the genes Orthopedia (Otp), Distal-less 5 (Dlx5), Sonic Hedgehog (Shh), and Nk2 homeobox 1 (Nkx2.1). At embryonic day 10.5 (E10.5), Sst mRNA was first detectable in the anterobasal nucleus, a Nkx2.1-, Shh-, and Otp-positive basal domain. By E13.5, nascent Sst expression was also related to two additional Otp-positive domains within the alar plate and one in the basal plate. In the alar plate, Sst-positive cells were observed in rostral and caudal ventral subdomains of the Otp-positive paraventricular complex. An additional basal Sst-expressing cell group was found within a longitudinal Otp-positive periretromamillary band that separates the retromamillary area from tuberal areas. Apart of subsequent growth of these initial populations, at E13.5 and E15.5 some Sst-positive derivatives migrate tangentially into neighboring regions. A subset of cells produced at the anterobasal nucleus disperses ventralward into the shell of the ventromedial hypothalamic nucleus and the arcuate nucleus. Cells from the rostroventral paraventricular subdomain reach the suboptic nucleus...

Proteomic Analysis of Anti-inflammatory Effects of a Kampo (Japanese Herbal) Medicine “Shoseiryuto (Xiao-Qing-Long-Tang)” on Airway Inflammation in a Mouse Model

Nagai, Takayuki; Nakao, Marino; Shimizu, Yuliko; Kodera, Yoshio; Oh-Ishi, Masamichi; Maeda, Tadakazu; Yamada, Haruki
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
Effects of a Kampo (Japanese herbal) medicine “shoseiryuto (SST, xiao-qing-long-tang in Chinese)”, which has been used for the treatment of allergic bronchial asthma clinically, were examined on ovalbumin (OVA)-sensitized allergic airway inflammation model (i.e., bronchial asthma) in a mouse. When SST was orally administered at 0.5 g kg−1 day−1 from day 1 to 6 after OVA inhalation, SST reduced the inflammation in lung tissue, the number of eosinophils and the OVA-specific immunoglobulin E (IgE) antibody titer in bronchoalveolar lavage (BAL) fluids at 7 days after the OVA inhalation. SST also reduced the airway hyperreactivity at 6 days after the OVA inhalation. Proteomic analysis with the agarose two-dimensional electrophoresis showed that the expression of spectrin α2 was reduced in the lung tissue of OVA-sensitized mice and SST recovered the expression. Western blot and immunohistochemical analyses of lung tissue also confirmed this result. When prednisolone was orally administered at 3 mg kg−1 day−1 from day 1 to 6 after OVA inhalation, the inflammation in lung tissue, the number of eosinophils in BAL fluids and airway hyperreactivity were reduced in the OVA-sensitized mice. However, prednisolone did not reduce the OVA-specific IgE antibody titer in BAL fluids and did not recover the expression of spectrin α2 in lung tissue. These results suggest that at least a part of action mechanism of SST against OVA-sensitized allergic airway inflammation in a mouse model is different from that of prednisolone.

Cortistatin Is Not a Somatostatin Analogue but Stimulates Prolactin Release and Inhibits GH and ACTH in a Gender-Dependent Fashion: Potential Role of Ghrelin

Córdoba-Chacón, José; Gahete, Manuel D.; Pozo-Salas, Ana I.; Martínez-Fuentes, Antonio J.; de Lecea, Luis; Gracia-Navarro, Francisco; Kineman, Rhonda D.; Castaño, Justo P.; Luque, Raul M.
Fonte: Endocrine Society Publicador: Endocrine Society
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
Cortistatin (CST) and somatostatin (SST) evolve from a common ancestral gene and share remarkable structural, pharmacological, and functional homologies. Although CST has been considered as a natural SST-analogue acting through their shared receptors (SST receptors 1–5), emerging evidence indicates that these peptides might in fact exert unique roles via selective receptors [e.g. CST, not SST, binds ghrelin receptor growth hormone secretagogue receptor type 1a (GHS-R1a)]. To determine whether the role of endogenous CST is different from SST, we characterized the endocrine-metabolic phenotype of male/female CST null mice (cort−/−) at hypothalamic-pituitary-systemic (pancreas-stomach-adrenal-liver) levels. Also, CST effects on hormone expression/secretion were evaluated in primary pituitary cell cultures from male/female mice and female primates (baboons). Specifically, CST exerted an unexpected stimulatory role on prolactin (PRL) secretion, because both male/female cort−/− mice had reduced PRL levels, and CST treatment (in vivo and in vitro) increased PRL secretion, which could be blocked by a GHS-R1a antagonist in vitro and likely relates to the decreased success of female cort−/− in first-litter pup care at weaning. In contrast...

Regional Variation in Human Supraspinatus Tendon Proteoglycans: Decorin, Biglycan, and Aggrecan

Matuszewski, Paul E; Chen, Yi-Ling; Szczesny, Spencer E; Lake, Spencer; Elliott, Dawn M; Soslowsky, Louis J; Dodge, George R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
While tendons typically undergo primarily tensile loading, the human supraspinatus tendon (SST) experiences substantial amounts of tension, compression, and shear in vivo. As a result, the functional roles of the extracellular matrix components, in particular the proteoglycans (PGs), are likely complex and important. The goal of this study was to determine the PG content in specific regions of the SST that exhibit differing mechanical function. The concentration of aggrecan, biglycan, and decorin were determined in six regions of the human SST using immunochemical techniques. We hypothesized that: aggrecan concentrations would be highest in areas where the tendon likely experiences compression; biglycan levels would be highest in regions likely subjected to injury and/or active remodeling such as the anterior regions; decorin concentrations would be highest in regions of greatest tensile stiffness. Our results generally supported these hypotheses and demonstrated that aggrecan and biglycan share regional variability, with increased concentration in the anterior and posterior regions and smaller concentration in the medial regions. Decorin, however, was in high concentration throughout all regions. The data presented in this study represent the first regional measurements of PG in the SST. Together with our previous regional measurements of mechanical properties...

Acute Slices of Mice Testis Seminiferous Tubules Unveil Spontaneous and Synchronous Ca2+ Oscillations in Germ Cell Clusters1

Sánchez-Cárdenas, Claudia; Guerrero, Adán; Treviño, Claudia Lydia; Hernández-Cruz, Arturo; Darszon, Alberto
Fonte: Society for the Study of Reproduction, Inc. Publicador: Society for the Study of Reproduction, Inc.
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
Spermatogenic cell differentiation involves changes in the concentration of cytoplasmic Ca2+ ([Ca2+]i); however, very few studies exist on [Ca2+]i dynamics in these cells. Other tissues display Ca2+ oscillations involving multicellular functional arrangements. These phenomena have been studied in acute slice preparations that preserve tissue architecture and intercellular communications. Here we report the implementation of intracellular Ca2+ imaging in a sliced seminiferous tubule (SST) preparation to visualize [Ca2+]i changes of living germ cells in situ within the SST preparation. Ca2+ imaging revealed that a subpopulation of male germ cells display spontaneous [Ca2+]i fluctuations resulting from Ca2+ entry possibly throughout CaV3 channels. These [Ca2+]i fluctuation patterns are also present in single acutely dissociated germ cells, but they differ from those recorded from germ cells in the SST preparation. Often, spontaneous Ca2+ fluctuations of spermatogenic cells in the SST occur synchronously, so that clusters of cells can display Ca2+ oscillations for at least 10 min. Synchronous Ca2+ oscillations could be mediated by intercellular communication via gap junctions, although intercellular bridges could also be involved. We also observed an increase in [Ca2+]i after testosterone application...

Mesoscale Variation of Mechanisms Contributing to Stability in Rocky Shore Communities

Valdivia, Nelson; González, Andrés E.; Manzur, Tatiana; Broitman, Bernardo R.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 11/01/2013 EN
Relevância na Pesquisa
17.17%
Environmental fluctuations can generate asynchronous species’ fluctuations and community stability, due to compensatory dynamics of species with different environmental tolerances. We tested this hypothesis in intertidal hard-bottom communities of north-central Chile, where a persistent upwelling centre maintains a mosaic in sea surface temperatures (SST) over 10s of kilometres along the shore. Coastal upwelling implies colder and temporally more stable SST relative to downstream sites. Uni- and multivariate analyses of multiyear timeseries of SST and species abundances showed more asynchronous fluctuations and higher stability in sites characterised by warmer and more variable SST. Nevertheless, these effects were weakened after including data obtained in sites affected by less persistent upwelling centres. Further, dominant species were more stable in sites exposed to high SST variability. The strength of other processes that can influence community stability, chiefly statistical averaging and overyielding, did not vary significantly between SST regimes. Our results provide observational evidence supporting the idea that exogenously driven compensatory dynamics and the stabilising effects of dominant species can determine the stability of ecosystems facing environmental fluctuations.

Evaluation of novel tests of neuromuscular function based on brief muscle actions

Bozic, Predrag R.; Celik, Ozgur; Uygur, Mehmet; Knight, Christopher A; Jaric, Slobodan
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/2013 EN
Relevância na Pesquisa
17.17%
Although widely used, the standard strength test (SST) is known to provide moderate correlations with functional measures, while being based on sustained maximum forces and a relatively large number of trials. The aim of the present study was to compare the concurrent (with respect to SST) and external validity (with respect to the standard balance and maximum power output tests) of two alternate tests of neuromuscular function based on brief isometric actions. The first test provides a slope between the rates of torque development (RTD) and peak torques (T) measured from a number of consecutive rapid actions performed across a wide range of T levels (brief force pulses; BFP). The second test (alternating consecutive maximum contractions; ACMC) provides T and RTD from multiple cycles of rapid alternating maximum actions of two antagonistic muscle groups. The results obtained from 29 young and healthy subjects revealed moderate-to-high concurrent validity of ACMC (median r=0.56; p<0.05) and its similar, if not higher external validity than SST. Conversely, both the concurrent and external validity of BFP appeared to be relatively low (r=0.23; p>0.05). Since ACMC could also have advantage over SST by being based on somewhat lower and transitional muscle forces exerted and fewer trials are needed for testing two antagonistic muscles...

Topical Administration of Somatostatin Prevents Retinal Neurodegeneration in Experimental Diabetes

Hernández, Cristina; García-Ramírez, Marta; Corraliza, Lidia; Fernández-Carneado, Jimena; Farrera-Sinfreu, Josep; Ponsati, Berta; González-Rodríguez, Águeda; Valverde, Ángela M.; Simó, Rafael
Fonte: American Diabetes Association Publicador: American Diabetes Association
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
Retinal neurodegeneration is an early event in the pathogenesis of diabetic retinopathy (DR). Somatostatin (SST) is an endogenous neuroprotective peptide that is downregulated in the diabetic eye. The aim of the study was to test the usefulness of topical administration of SST in preventing retinal neurodegeneration. For this purpose, rats with streptozotocin-induced diabetes mellitus (STZ-DM) were treated with either SST eye drops or vehicle for 15 days. Nondiabetic rats treated with vehicle served as a control group. Functional abnormalities were assessed by electroretinography (ERG), and neurodegeneration was assessed by measuring glial activation and the apoptotic rate. In addition, proapoptotic (FasL, Bid, and activation of caspase-8 and caspase-3) and survival signaling pathways (BclxL) were examined. Intraretinal concentrations of glutamate and its main transporter glutamate/aspartate transporter (GLAST) were also determined. Treatment with SST eye drops prevented ERG abnormalities, glial activation, apoptosis, and the misbalance between proapoptotic and survival signaling detected in STZ-DM rats. In addition, SST eye drops inhibited glutamate accumulation in the retina and GLAST downregulation induced by diabetes mellitus. We conclude that topical administration of SST has a potent effect in preventing retinal neurodegeneration induced by diabetes mellitus. In addition...

The Role of the Neuropeptide Somatostatin on Methamphetamine and Glutamate-Induced Neurotoxicity in the Striatum of Mice

Afanador, Lauriaselle; Mexhitaj, Ina; Diaz, Carolyn; Ordonez, Dalila; Baker, Lisa; Angulo, Jesus A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.17%
A large body of evidence shows that methamphetamine (METH) causes sustained damage to the brain in animal models and human METH users. In chronic users there are indications of cognitive and motor deficits. Striatal neuropeptides are in a position to modulate the neurochemical effects of METH and consequently striatal neural damage. Somatostatin (SST) is an intrinsic striatal neuropeptide that has been shown to inhibit glutamate transmission; glutamate is integral to METH toxicity and contributes to nitric oxide (NO) synthesis. We hypothesize that SST will protect from METH by inhibition of NO synthesis and thus reducing oxidative stress. To this end, the SST analogue octreotide (OCT) was microinjected into the striatum prior to a systemic injection of METH (30 mg/kg). We then assessed 3-nitrotyrosine (3-NT), an indirect index of NO production, tyrosine hydroxylase (TH) protein levels (dopamine terminal marker) and Fluoro-Jade C positive cells (degenerating cells). The SST agonist OCT dose dependently attenuated the METH-induced accumulation of striatal 3-NT. Moreover, pretreatment with OCT effectively mitigated cell death but failed to protect dopamine terminals. Next we co-infused OCT and NMDA and measured 3-NT and Fluoro-Jade C staining. Treatment with OCT had no effect on these parameters. The data demonstrate that SST attenuates the METH-induced production of NO protecting the striatum from the METH-induced cell loss. However...