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Biomedical subjects

M García

Publications and source records attributed to M García.

At least 55 records · Page 3Linked to original sources
PubMed2003

Heat processing of barley and enzyme supplementation of diets for broilers.

The influence of heat processing (HP) of barley and enzyme supplementation (ES) of the diet on digestive and performance traits of broilers to 21 d was studied. There were four treatments arranged factorially with two barley-processing treatments (raw or heated), two levels of ES (0 or 500 ppm), and five replicates per treatment. Chicks fed HP barley grew faster than broilers fed raw barley until 8 d of age, but the effect disappeared thereafter. In general, ES improved broiler performance at all ages. Intestinal viscosity was increased by HP of barley (P < or = 0.05) and reduced by ES (P < or = 0.001), and the decrease in viscosity caused by ES was greater for HP than for raw barley diets (HP x ES; P < or = 0.05). Heat processing of barley and ES of the diet improved apparent retention of nutrients (P < or = 0.001). Age affected apparent retention of nutrients differently. For starch and neutral detergent fiber, retention increased linearly with age (P < or = 0.01), but for the remaining nutrients the retention decreased from d 4 to 8 and then increased until d 21 (P < or = 0.001). Also, the beneficial effects of HP on retention of nutrients were more pronounced at younger ages (HP x age; P < or = 0.05). Both HP (P < or = 0.001) and ES (P < or = 0.01) increased liver weight, and enzymes reduced the weights of pancreas (P < or = 0.05) and small intestine (P < or = 0.001). Villus height was improved by HP (P < or = 0.001) and ES (P < or = 0.01), but villus surface area was only improved by enzymes (P < or = 0.01). It was concluded that broiler performance is improved by HP of barley at early ages and by ES of the diet throughout the trial. Also, HP and ES increased apparent retention of nutrients, AMEn of the diet, and villus height.

Animal Nutritional Physiological Phenomena↗
PubMed2003

5-Hydroxytryptamine-induced vasodilator responses in the hindquarters of the anaesthetized rat, involve beta2-adrenoceptors.

These studies were conducted to examine the role of the vasoactive mediators nitric oxide (NO) and adrenaline (epinephrine) in the serotonin (5-hydroxytryptamine; 5-HT)-induced vasodilator response in the hindquarter vascular bed of anaesthetized rats. Intra-arterial administration of doses of 5-HT in the range 0.12-25 ng kg(-1) produced a dose-independent vasodilator effect in the hindquarters. The selective 5-HT(1D/1B) receptor agonist, L-694,247 at intra-arterial doses of 0.0012-1000 ng kg(-1), as well as adrenaline (at doses of 0.05-50 ng kg(-1) i.a.), mimicked the dose-independent vasodilator effect induced by intra-arterial administration of 5-HT. Intravenous pre-treatment with the selective beta2-receptor antagonist ICI 118,551 (0.5 mg kg(-1)) blocked the vasodilator effect of 5-HT, adrenaline and L-694,247. Additionally, the inhibitor of NO synthase NG-nitro-L-arginine (L-NAME) (at a dose of 10 mg kg(-1) i.v.) blocked the vasodilator action of acetylcholine 300-3000 ng kg(-1)) but did not modify 5-HT-induced vasodilatation. The vasodilator effect produced by intra-arterial administration of 5-HT in the hindquarters was significantly inhibited both 30 min after denervation of the lumbar sympathetic chains and 1 h after bilateral adrenalectomy. Our data suggest that in the in-situ autoperfused hindquarters of the rat 5-HT-induced vasodilatation is mediated by a local 5-HT(1D) or 5-HT(1D/1B) activation, which in turn mediates the adrenal release of adrenaline, which then produces beta2-activation and vasodilatation.

Animals↗
PubMed2003

Role of Müller glia in neuroprotection and regeneration in the retina.

Glial cells are thought to protect neurons from various neurological insults. When there is injury to retina, Müller cells, which are the predominant glial element in the retina, undergo significant morphological, cellular and molecular changes. Some of these changes reflect Müller cell involvement in protecting the retina from further damage. Müller cells express growth factors, neurotransmitter transporters and antioxidant agents that could have an important role in preventing excitotoxic damage to retinal neurons. Moreover, Müller cells contact to endothelial cells to facilitate the neovascularization process during hypoxic conditions. Finally, recent studies have pointed to a role of Müller cells in retina regeneration after damage, dedifferentiating to progenitor cells and then giving rise to different neuronal cell types. In this article we will review the role of Müller glia in neuroprotection and regeneration after damage in the retina.

Animals↗
PubMed2003

Social integration of juvenile amputees: comparison with a general population.

The objective was to assess the social integration of juvenile amputees according to marital status, schooling and occupation, and to compare it with the population of Asturias, Spain. A retrospective study was carried out of the juvenile amputees registered from 1976 to 1999 at the Prosthetics Unit of the Asturias Central Hospital (n=281 amputees). The proportion of single women amongst the amputees was greater than in the population of Asturias (p<0.05). Amongst the male amputees, relative to the general population, there was a larger proportion of the group with primary studies (p<0.001) and a smaller proportion with secondary studies (p<0.001). At the higher level (university) there were no differences, either in men or in women. As regards occupation, amongst the amputees a larger number was found who were retired or unemployed (p<0.05 and p<0.001). In conclusion, juvenile amputees do not show differences compared to the general population with regard to their attendance at a higher or university level of education. However, if their social integration is considered through occupation, male amputees show a greater proportion of unemployment, which is a clear reflection of their handicap.

Adolescent↗
PubMed2003

[Retinal ganglion cell neuroprotection in culture].

PURPOSE: To study the pig retinal ganglion cell (RGC) survival in culture, analysing the possible neuroprotective effect of retinal Müller glia (RMG) and brain-derived neurotrophic factor (BDNF). METHODS: Adult pig retina were dissociated and cultured under different conditions: 1) on laminin/poly-D-lysine-coated coverslips in chemically defined medium (CDM); 2) on laminin/poly-D-lysine-coated coverslips in CMD supplemented with BDNF; 3) on confluent monolayer cultures of RMG in CDM; 4) on laminin/poly-D-lysine substrate in conditioned medium obtained from RMG. RGCs were identified by immunocytochemistry using antibody against 68 kDa neurofilament and observed under an fluorescent microscope. RGCs were classified on the basis of the size, number and length of neurites, and their survival was assayed for each treatment. RESULTS: Confluent RMG substrates and RMG conditioned medium significantly increased the survival of cultured pig RGC. Moreover these two conditions increased the mean area of RGCs and enhanced neurite growth and elongation. Addition of BDNF to culture medium did not modify survival but increased RGC size, neurite number and neurite length. CONCLUSIONS: These findings demonstrate that factor(s) secreted by RMG exert beneficial effects on adult RGC survival and neurite regeneration in vitro, and might constitute important agent(s) for RGC neuroprotection. BDNF also increases the mean area of RGCs and enhances neurite growth but it does not increase the survival of RGCs.

Animals↗
PubMed2003

[Intracellular pathways leading to apoptosis of retinal cells].

Some ocular diseases, such as retinitis pigmentosa, age-related macular degeneration, glaucoma, retinal detachment, diabetic retinopathy or pathological myopia result in apoptotic death of retinal cells. Caspases are proteases that take part in the intracellular signaling pathways that cause apoptosis in different cell types. By using different experimental models, an increase in caspase activity in retinal cells after damage has been shown. However, some studies have shown that other molecules apart from caspases are activated during apoptosis in the retina. Moreover, the type of caspase that is activated seems to be different depending on the type of retinal cell and the pathology analysed. Inhibition of the processes that result in retinal cell apoptosis could decrease the number of dead cells and prevent the irreversible loss of visual function associated with some pathologies such as glaucoma. In this study we aim to review the basic research studies published in the last years in order to know the molecules and pathways involved in the processes which cause apoptosis of the different types of retinal cells.

Apoptosis↗
PubMed2003

Occupational rhinitis and bronchial asthma due to TBTU and HBTU sensitization.

Exposure to an increasing amount of products in the work environment is leading to new cases of occupational asthma among workers. We report the case of a worker at a pharmaceutical plant who developed occupational rhinitis and bronchial asthma due to HBTU: 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate and TBTU: 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate sensitization, two chemical products widely used in peptide synthesis and coupling. Skin tests (prick test) with HBTU and TBTU solutions in PBS were positive at a concentration of 1 mg/ml. Skin tests with the same solutions in 10 atopic controls yielded a negative result. Nasal challenge tests with these products were positive with HBTU at a concentration of 0.01 mg/ml and TBTU at a concentration of 1 mg/ml. In both cases PNIF (peak nasal inspiratory flow) decreased by more than 60% and severe sneezing and rhinorrhea were induced. Nasal challenge tests performed on 10 atopic controls with TBTU and HBTU at a concentration of 1 mg/ml were negative. We conclude that the patient presents occupational rhinitis and bronchial asthma due to TBTU and HBTU; the operational mechanism is probably immunological IgE-mediated given the positive prick tests and nasal challenge with these products.

Adult↗
PubMed2003

[Prognostic significance and clinic utility of serum and immunohistochemical cathepsin B levels in colorectal cancer].

BACKGROUND: Aproximately one third of node-negative colorectal cancer recur suggesting the presence of micrometastasis not detected by conventional histopathologic methods. We think that the role of enzymes like Cathepsin B play in the process of invasion and metastasis in colorectal cancer might identify at earlier stages patients with high risk of shorter survival and who need more aggressive treatment. Our porpuse is to evaluate the prognostic significance of preoperative serum and inmunohistochemical levels of cathepsin B to identify colorectal carcinomas with worse prognostic. METHODS: Fifty five patients undergoing surgical treatment for colorectal cancer from 1998 to 2000. As a control group sera from 23 patients with acute appendicitis. Serum levels of cathepsin B were obtained preoperatively (KRKA, Novo Slovenia;ng/ml); cathepsin B inmunoreactivity was determinated after surgical treatment, (C-19, Santa Cruz Biotechnology). Serum levels of CEA (Inmulit 2000 CEA), and CA 19,9 (Inmulite Gi-Ma, Diagnostic Products Corporation, Los Angeles, CA), and p53 expression (Dako) were determinated in patients with colorectal cancer. Survival analysis was realized using Cox and Kaplan-Meier methods (SPSS 10.0 for Windows). RESULTS: The mean age of patients with colorectal cancer was 68 years (range 39-87 years). 29 males and 26 females. Tumor size was 4.6 cms., range 1-12. Rectal localization, 32.2%. Moderately differentiated, 49.1%. The median serum and inmunohistochemical levels of cathepsin B were 5.74 ng/ml and 29.56% in patients with acute appendicitis respectively. Preoperative serum levels in patients with colorectal cancer were: CEA, 46.04 ng/ml (range 0.21-7.32 ); CA 19,9, 110.52 UI/ml, (range 2.5-1920); and Cathepsin B, 6.94 ng/ml, range 3.57-11.6). Inmunohistochemical results were: p53, 44.36%, (range 0-95); Cathepsin B, 66.9% (range 10-90). Serum and inmunhistochemical values were significantly increased in patients with colorectal cancer when compared with control group, p=0,011 and p=0,000. High serum levels of cathepsib B were significantly associated wiyh shorter survival of patients with colorectal cancer in univariate and multivariate methods, p=0.041;HR 1.281 95%CI (1.043-1.716) and p= 0.022; HR 1.338.955 CI (1.043-1.716). CONCLUSIONS: Cathepsin B can be used like an independent prognostic tumoral marker in colorectal cancer. Preoperative serum levels over 6.94 ng/ml, are associated with worse prognostic and shorter survival.

Adult↗
PubMed2003

[Infective endocarditis in the elderly].

BACKGROUND: The influence of age on the clinical presentation and on the prognosis of infective endocarditis (IE) is unclear. Our aim was to analyse the epidemiologic, clinical and bacteriological characteristics of IE in the elderly compared with younger adult patients. PATIENTS AND METHODS A retrospective study of all patients with IE non intravenous drug users diagnosed in our hospital during the period from 1990 to 2000. We used the Duke criteria to compare the characteristics of 46 episodes of definitive IE in elderly patients (>65 years old ) and of 46 episodes in younger adult patients (20-64 years of age ). RESULTS: No significant differences were observed among the two groups with respect to the delay in diagnosed, possible source of infection, the frequency of positive blood cultures and the type of infective organism, clinical presentation and evolution of the IE. Elderly patients more often had risk factors predisposing (degenerative valvular disease, prosthetic valve and pacemaker ), which decreased the sensitivity of transthoracic echocardiography to 46.5% compared with 64.4% in the younger patients. Transesophageal echocardiography improved the diagnostic of IE in the 37.2% in elderly patients. The patients in the both groups underwent surgical therapy with similar frequency (36.9% in the elderly and the 39.1% in the younger adult patient ) and the mortality rate not was significantly higher in the elderly (19.5%) than in the younger adult patients (10.8%). CONCLUSIONS: The age itself is not a poor prognostic, and should not be used prejudicially in denying a early and aggressive treatment of the patients with IE.

Adult↗
PubMed2002

IGF1 gene transfer into skeletal muscle using recombinant adeno-associated virus in a rat model of liver cirrhosis.

Systemic administration of recombinant IGF1 at low levels has been shown to improve hepatic function, nutritional status and testicular atrophy in rats with CCl4-induced cirrhosis. We have developed a recombinant adeno-associated (rAAV) viral vector containing the cDNA for rat IGF1 and confirmed the expression of IGF1 after intramuscular injection of this vector in a rat model of liver cirrhosis. Although weight of injected muscles was significantly increased in rats with mild cirrhosis, this was not the case in rats with advanced, de-compensated cirrhosis. Furthermore, we found no significant amelioration of liver damage in treated rats at any stage of liver cirrhosis. Our results suggest that IGF1 gene transfer into muscle results in a local effect, at least at the vector dose employed here.

Animals↗
PubMed2002

Fragile sites in human and Macaca fascicularis chromosomes are breakpoints in chromosome evolution.

We have analysed the expression of aphidicolin-induced common fragile sites at two different aphidicolin concentrations (0.1 micromol/L and 0.2 micromol/L) in three female and one male crab-eating macaques (Macaca fascicularis, Cercopithecidae, Catarrhini). A total of 3948 metaphases were analysed: 1754 in cultures exposed to 0.1 micromol/L aphidicolin, 1261 in cultures exposed to 0.2 micromol/L aphidicolin and 933 in controls. The number of breaks and gaps detected ranged from 439 in cultures exposed to 0.1 micromol/L aphidicolin to 2061 in cultures exposed to 0.2 micromol/L aphidicolin. The use of a multinomial FSM statistical model allowed us to identify 95 fragile sites in the chromosomes of M. fascicularis, of which only 16 are expressed in all four specimens. A comparative study between the chromosomes of M. fascicularis and man has demonstrated that 38 human common fragile sites (50%) are found in the equivalent location in M. fascicularis. The analysis of the rearrangements that have taken place during chromosome evolution has revealed that the breakpoints involved in these rearrangements correspond significantly (p < 0.025) to the location of M. fascicularis fragile sites.

Animals↗
PubMed2002

Myeloablation enhances engraftment of transduced murine hematopoietic cells, but does not influence long-term expression of the transgene.

To investigate to what extent myeloablation, graft size, and ex vivo manipulation influence the engraftment and long-term survival of transduced murine hematopoietic cells, groups of C57BL/6J (CD45.2) mice receiving total body irradiation (TBI) (1-9 Gy) or no irradiation were transplanted with either transduced bone marrow (BM) cells, at two cell doses, or with fresh BM cells from B6/SJL (CD45.1) congenic mice. Short (40 days) and long-term (5 months) engraftment and transgene expression were measured by FACS analysis. No donor cells were detected in the hematopoietic tissues of non-myeloablated mice, whereas in the irradiated animals, levels of engraftment correlated well with the dose of TBI administered. Similar percentages of transgene-expressing cells were found in the grafted hematopoietic cells of all groups of mice, regardless of the dose of TBI administered or the level of engraftment achieved. This suggests that the engrafted animals could become tolerant to the transgene product (enhanced green fluorescent protein, EGFP). Our results indicate that TBI facilitates the engraftment of manipulated hematopoietic cells in a dose-dependent manner, that mice engrafted with EGFP(+) hematopoietic cells probably acquire tolerance to EGFP, and that increasing the graft size and reducing the ex vivo manipulation required for retroviral gene transfer of hematopoietic cells also enhances their engrafting potential.

Animals↗
PubMed2002

Veratridine, but not elevated K+, inhibits excitatory amino acid transporter activity in rat hippocampal slices.

PURPOSE: Excitatory amino acid transporter (EAAT) activity prevents Glu from reaching toxic levels, but their contribution to epileptogenesis remains controversial. We examined how the convulsant veratridine causes inhibition of EAAT activity and how it differs from the effects of another convulsant, high (50 mM) K+, that also increases Na+ conductance. METHODS: Transverse rat hippocampal slices were incubated for 1 h with 100 microM veratridine in oxygenated artificial cerebrospinal fluid (aCSF) with or without extracellular Ca2+. The medium was replaced by 50 microM[(3)H]glutamate in aCSF, and the slices incubated for 10 min at 37 degrees C. The slices were washed 3 times with cold aCSF after removal of the extracellular medium, and the radioactivity was quantified after solubilization of the slices. RESULTS: Veratridine caused a time- and dose-dependent decrease, whereas high K+ had no effect on EAAT activity. The effects of veratridine on EAAT activity were not prevented by tetrodotoxin (TTX; 10 microM). Coincubation of ouabain with veratridine resulted in further decreases of EAAT activity. Removal of extracellular Ca2+ potentiated the inhibitory effects of veratridine (and other convulsants) on EAAT activity. Chelation of intracellular Ca2+ with BAPTA also increased the inhibitory effects of veratridine on EAAT activity. CONCLUSIONS: Veratridine caused changes Ca2+ dynamics that led to inhibition of EAAT activity. Such changes in EAAT activity can contribute to the sustained epileptiform activity caused by veratridine.

Amino Acid Transport Systems↗
PubMed2002

Flow-cytometric assessment of lymphocyte cytokine production in tuberculosis.

We assessed by flow-cytometry the Th1/Th2 profiles in peripheral blood lymphocytes (PBL) from patients with active tuberculosis (TB), before and after antituberculous therapy, and from healthy tuberculin-positive and -negative reactors. PBL from patients showed a reduced potential for Th1-cytokine (notably IFN- gamma) production after culture with a policlonal stimulus. When these PBL from patients were cultured with a M. tuberculosis (MTB)-specific antigen such as PPD (10 microg/ml), there was no detectable production of Th1 cytokines. Only the Th2 cytokine IL10 was detected in PBL from patients but not from controls. However, at the site of the tuberculosis disease, T lymphocytes from bronchoalveolar lavage, after culture with PPD, produced IFN- gamma. After completion of tuberculosis therapy, PBL did not produce IL10. These data indicate that the immunosuppression observed in PBL during active tuberculosis infection may be related to IL10 production, and to the compartmentalization of the antigen-Th1 response to sites of active MTB infection.

Adult↗
PubMed2002

Behaviour of pesticides in a water/sediment system under laboratory and field conditions.

Experiments were conducted in order to evaluate the behaviour of some pesticides commonly used in rice production. At a laboratory scale, but exposed to the environmental conditions, a known concentration of pesticides in water flowed through a cement channel over a sediment layer, at a constant flow rate. The collected water was homogenised and analysed by gas chromatography/HPLC to assess the concentration of each pesticide. Under these conditions, the reduction of each pestcide concentration in water depends on the nature of it and on the water flow rate. The lower the flow rate, the grater the reduction in the concentration of pesticides in the water that ran over the sediment layer. Experiments were also carried out under field conditions, using a 1200 m length, 2 m width and 0.3 m depth rice field channel. A pesticide mixture of known concentration was poured on the flowing water and mixed thoroughly. After the arrival of this contaminated water at preestablished sampling points down the stream, the concentration of each pesticide in water was determined. The longer the distance of the sampling points downstream from the starting point, the lower the pesticide concentration found. Only a few pesticides were detected at the 1200 m sampling point, but at very low concentration. The others were not detected. It was pointed out that the channel length was the most important factor in the reduction of the pesticide concentration in the flowing water. The influence of the flow rate on this reduction could not be clearly related as in the laboratory experiments.

Agriculture↗