Biomedical subjects

M E García

Publications and source records attributed to M E García.

At least 19 recordsLinked to original sources

PubMed2005

Ecotoxicological assessment for receiving waters with the premetamorphic tadpoles acute assay.

The toxicity of receiving waters was evaluated by means of the young tadpoles assays. The sentinel organism was Bufo arenarum, an indigenous anuran species. The assayed water samples were taken from a highly polluted urban watercourse (Reconquista River, Buenos Aires, Argentina), characterized by high concentration of nitrites, phosphates and heavy metals. The toxicity of water samples was assessed performing the pass-fail test and by means of the NOEC and LC(50); TUs (toxic units) were also calculated. The effect of the addition of a positive control (Cd) on the toxicity of the river water samples was also examined. Water samples of three sites, characterised by their different degree of pollution, were assayed. The lethal response had a clear cut correspondence with the water quality of the sample evaluated by means of physicochemical parameters. In most cases, the dilution of the samples resulted in a significant reduction of their toxicity to TU values compatible to those stated by the USEPA for industrial effluents. It was concluded that (a) the used Bufo arenarum bioassay was an adequate method for assessing the toxicity of natural polluted water samples and (b) the three considered endpoints showed no important differences after 48 or 96 h of exposure, therefore we concluded that it may not be necessary to extend the assay for a longer period than 48 h.

Animals↗

PubMed2005

Effect of co-substrate, biomass and sulfate concentration on the performance of a control strategy used to determine the anaerobic stage length of an anaerobic/aerobic SBR degrading p-nitrophenol.

The effect of the p-nitrophenol to propionic acid ratio, the biomass concentration, and the presence of sulfates on the performance of a control strategy of an anaerobic/aerobic SBR degrading p-nitrophenol was studied. The duration of the anaerobic stage was controlled by an algorithm based on the on-line measurement of the oxidation-reduction potential, which indicates the end of the reduction of p-nitrophenol to p-aminophenol. It was observed that no significant influence on the performance of the algorithm was found when the co-substrate, the biomass concentration and the presence of sulfates were varied, indicating the robustness of the control strategy. Only for the case when a low concentration of cosubstrate was used, was there no transformation of p-nitrophenol.

Aerobiosis↗

PubMed2004

Islet neogenesis: an apparent key component of long-term pancreas adaptation to increased insulin demand.

This study aimed to determine the relative importance of different functional and morphological pancreatic changes induced by the chronic administration of a sucrose-rich diet (SRD) to maintain normal glucose homeostasis. Male Wistar rats were fed either sucrose (SRD) or starch (CD) for 6 and 12 months. At both periods, serum glucose and triacylglycerol levels were significantly higher (P<0.05; paired and unpaired Student's t-test) in SRD rats. Serum insulin levels were significantly lower in SRD only at 12 months. At 6 months, the insulin secretion dose-response curve in SRD rats showed a shift to the left that was no longer observed at 12 months, when SRD islets decreased their response to 16 mM glucose. At 6 months, SRD rats showed a significant increase in beta-cell volume density (Vvi) and islet cell replication rate, together with a decrease in beta-cell apoptotic rate. Changes were not detected in the percentage of PDX-1- and islet neogenesis associated protein (INGAP)-positive cells. Conversely, at 12 months, there was a significant decrease in beta-cell Vvi and in the percentage of PDX-1-positive cells; the islet cell replication rate was not modified, and the number of apoptotic beta-cells increased significantly. No signs of increased neogenesis or INGAP-positive cells were recorded at any period in SRD rats. Our results show that SRD rats are unable to develop functional and morphological pancreatic reactive changes sufficient to maintain normal glucose and triacylglycerol levels for a long period. Such failure could be ascribed to their inability to increase the rate of neogenesis and of INGAP production.

Adaptation, Physiological↗

PubMed2003

Expression of islet neogenesis-associated protein in islets of normal hamsters.

The aim of the present study was to test the possible presence and expression of islet neogenesis-associated protein (INGAP) in islet cells of normal adult hamsters. Pancreata from normal male Syrian hamsters were removed to perform the following studies. (i) Western blot analysis using the cytosolic fraction from homogenates of isolated islets, exocrine tIssue and whole pancreas, and rabbit INGAP-specific antibody. (ii) Immunohistochemical identification of INGAP-positive cells in fixed sections of intact pancreata, fresh and 72 h cultured islets (isolated by collagenase digestion), and smears of exocrine pancreatic cells, using the same INGAP-specific antibody and streptavidin-biotin complex. (iii) RT-PCR using total RNA extracted from isolated islets and from exocrine tIssue as template, and a specific pair of primers. (iv) Control of the sequence of the PCR products. INGAP protein was identified by Western blot in the cytosolic fraction of homogenates from fresh isolated islets, exocrine cells and whole fresh pancreas. INGAP-immunopositive cells were observed in duct, exocrine and islet cells in either fixed intact or digested pancreatic tIssue. INGAP mRNA was identified in samples of total RNA from fresh and cultured isolated islets and from exocrine cells. Our data demonstrate that INGAP is present and expressed in islets and in exocrine pancreatic cells of normal hamsters. The ubiquitous localization of INGAP suggests its possible role in the physiological process of islet growth and its protective effect upon streptozotocin-induced diabetes.

Animals↗

PubMed2002

Prevalence and antimicrobial-resistance of S. pneumoniae and S. pyogenes in healthy children in the region of Madrid.

UNLABELLED: Streptococcus pneumoniae and Streptococcus pyogenes are common agents of respiratory or ORL pathology. Pneumococcus sensitivity has progressively decreased to penicillin and other antimicrobial agents, mainly in south of Europe, but this resistance report can be erroneous by a selection bias, because they sampled only hospital cases. OBJECTIVES: To determine the prevalence, antimicrobial susceptibility and risk factors of S. pneumoniae and S. pyogenes in healthy children under 5 years of age who go to infant school. SUBJECT AND METHODS: Cross sectional study in six infant schools. An epidemiological inquiry (risk factors of carrier state) was filled out and a nasopharyngeal specimen was taken from each child, S. pneumoniae and S. pyogenes were identified and antimicrobial tests were performed. RESULTS: We have studied 156 children with a mean age of 2.24 (standard deviation (S.D.), 0.85) and 58% have been treated with antibiotic in the last 3 months. The prevalence of S. pneumoniae or S. pyogenes were 12.2 and 5.1%, respectively. S. pyogenes only was isolated in two schools. Age was associated with S. pyogenes carrier but the rest of studied factors have no statistical significance with both microorganisms. All the S. pneumoniae showed resistance to one or more antibiotic (mainly to clavunate-amoxycillin: 94.7%), while S. pyogenes only was resistant to clavunate-amoxycillin. CONCLUSION: Healthy children (0-4 years) with antibiotherapy in last 3 months have a great frequency of resistant S. pneumoniae. It is necessary to reduce the antibiotic use at home (Medical education).

Anti-Bacterial Agents↗

PubMed2002

Expression and cellular distribution pattern of plasma membrane calcium pump isoforms in rat pancreatic islets.

This work is aimed at identifying the presence and cellular distribution pattern of plasma membrane calcium pump (PMCA) isoforms in normal rat pancreatic islet. Microsomal fractions of isolated islets and exocrine tissue were analyzed to detect different PMCA isoforms. The cellular distribution pattern of these PMCAs in the islets was also studied in fixed pancreas sections incubated with antibodies against PMCAs and insulin. Antibody 5F10, which reacts with all PMCA variants, showed multiple bands in the blots in the 127-134 kDa region, indicating the presence of several isoforms. Microsomes also reacted positively with specific antibodies for individual PMCA isoforms, generating a band of the expected size. Antibody 5F10 immunocytochemically labeled the plasma cell membrane of both b- and non-b-cells, but predominantly the former. All islet cells were also labeled with antibodies against isoforms 1 and 4, while the antibody reacting with isoform 3 labeled exclusively b-cells. A few b- and non-b-cells were positively labeled with the antibody reacting with PMCA b variant. Negative results were obtained with the antibody against isoform 2. Further studies, together with previous reports on the modulatory effect of insulin secretagogues and blockers upon PMCA activity, may provide evidence of the importance of this particular PMCA expression for islet function under normal and pathological conditions.

Animals↗

PubMed2001

Tadpoles assay: its application to a water toxicity assessment of a polluted urban river.

The acute toxicity assay with premetamorphic tadpoles of Bufo arenarum as sentinel organism was applied to evaluate the quality of two water samples taken from three sites of the Reconquista River, an urban watercourse which is recipient of both untreated industrial effluents and domestic wastes. The results of the 96 hr bioassays were compared with the physicochemical parameters determined in the samples. Mortality rates in each sample were compared using the Bonferroni's test and a stepwise regression analysis of mortality and physicochemical parameters was done. In this way, it was possible to build up consistent descriptive models which showed that pH, Cl- Cd2+ and Cu2+ concentrations in the river water were significant independent variables and might explain, under the experimental conditions, the recorded toxicity effects of the tested samples. Because of its simplicity, low cost and reliability it was suggested the tadpoles bioassay be included in the set of tests used in integrated program of freshwater pollution.

Animals↗

PubMed2001

A clinical case of canine mycotic pneumonia.

A bronchopneumonic process diagnosed as mycotic in origin is described. The dog fully recovered after 120 days of treatment with ketoconazole. Determination of the serological level of anti-IgG against Aspergillus was very useful in the follow-up, because the clinical improvement of the animal was evident long before the antibody level dropped significantly.

Animals↗

PubMed2000

Snakebites and ethnobotany in the northwest region of Colombia: Part I: traditional use of plants.

In Antioquia and Chocó, traditional healers attend 60% of snakebites. With the aim to produce an inventory of the plants used by the healers to treat snakebites and to document the methods of preparation, administration, the dosage, number of patients treated throughout their years of practice with treatment results, 20 healers with experience in Bothrops, Porthidium and Bothriechis envenomations were interviewed between August, 1996 and November, 1998. They belong to nine black and three indigenous rural communities located near the towns of Bojayá, Vigía del Fuerte, Unguía (Atrato river valley), Nuquí and Bahía Solano (Pacific coast). Based on field interviews, 101 species of plants were identified as used to treat snakebites. The part used of each plant varies according to the species. Sixty plants are used in the form of drinks prepared by infusion, decoction or maceration; 78 as external baths on the affected extremity; 11 for steam application and 39 for poultices; the latter is used mainly when the bite is complicated by local necrosis. In mild and moderate envenomations, they generally use a mixture of three plants, while in severe cases they mix from five to 12, a handful of each one. Treatment is generally performed for 1-3 days, when the patient reacts positively. They reported to have treated 454 patients during their years of experience, 20 of them (4.4%) died. With the guidance of the healers, 77 species of plants were collected and photographed. These plants belong to 41 families, of which Piperaceae (13 species), Araceae (six species), Asteraceae (five species) and Gesneriaceae (three species) have the highest number of species.

Animals↗

PubMed2000

Snakebites and ethnobotany in the northwest region of Colombia: Part II: neutralization of lethal and enzymatic effects of Bothrops atrox venom.

Twelve of 74 ethanolic extracts of plants used by traditional healers for snakebites in the northwest region of Colombia, were active against lethal effect of Bothrops atrox venom when they were i.p. injected into mice (18-20 g). After preincubation of sublethal doses of every extract (0.5-4.0 mg/mouse) with 1.5 i.p. lethal dose 50% (LD50) (99.3 microg) of venom, seven of them demonstrated 100% neutralizing capacity within 48 h. These were the stem barks of Brownea rosademonte (Caesalpiniaceae) and Tabebuia rosea (Bignoniaceae); rhizomes of Renealmia alpinia (Zingiberaceae) and Heliconia curtispatha (Heliconiaceae); the whole plants of Pleopeltis percussa (Polypodiaceae) and Trichomanes elegans (Hymenophyllaceae); and the ripe fruits of Citrus limon (Rutaceae). The other five extracts showing partial neutralization (45-80%; 10-30% survival rate in the control group receiving the venom alone; P<0.05) were: leaves, branches and stem of Costus lasius (Costaceae); the whole plant of Sida acuta (Malvaceae); rhizomes of Dracontium croatii (Araceae); leaves and branches of Bixa orellana (Bixaceae) and Struthanthus orbicularis (Loranthaceae). When the extracts were independently administered per oral or i.p. route 60 min before an i.m. venom injection (204 microg=1.5 i.m. LD50), C. limon, T. elegans, B. orellana and T. rosea extracts had partial and significant neutralizing capacity against B. atrox venom lethal effect. C. limon extract was also partially effective when it was administered either i.v. 15 min before or i.p. 5 min after an i.m. venom injection. Three of the 12 extracts with anti-lethal effect (C. limon, D. croatii and S. acuta) were devoid of antiphospholipase A2 activity, when they were tested against one minimum indirect hemolytic dose of B. atrox venom (2 microg) in agarose-erythrocyte-egg yolk gels.

Animals↗

PubMed2000

Disseminated mycoses in a dog by Paecilomyces sp.

We describe a case of canine mycoses initially diagnosed by clinical signs and enzyme-linked immunosorbent assay anti-fungal test, and later confirmed by the isolation of Paecilomyces sp. during the post-mortem examination. The fungus was isolated from lesions in the kidneys, mitral valve, abdominal aorta and vertebral discs. In this kind of process, it is important to identify the responsible agent early in order to make a study of anti-fungal susceptibility and establish effective treatment.

Animals↗

PubMed2000

Optimum incubation conditions for the isolation of yeasts from canine otitis externa.

Samples from otitis externa in the dog were cultured on a variety of media under different conditions of incubation in order to assess the most suitable conditions, especially for the isolation of Malassezia pachydermatis. Columbia blood and MacConkey agar at 37 degrees C for 24 h with air and Sabouraud glucose agar under microaerophilic conditions for 48 h at 37 degrees C were considered the ideal combination.

Animals↗

PubMed2000

[Mycoses in domestic animals].

In the present paper we will present a general view of the main mycoses affecting domestic animals. In the dog, we show the importance of the dermatophytoses, increased by its zoonosic character and the problem of the false negatives in the traditional microbiological culture. Under the general term of systemic mycoses we include a series of conditions considered usually as aspergillosis, bat with more and more fungal species implicated as possible etiological agents. In addition, fungi, especially yeasts, are being implicated in canine otitis; in our laboratory 86 % of canine chronic otitis involve a yeast etiology, alone or in collaboration with bacteria. In the cat, dermatophytes are more common than in the dog, and are the main source of infection in man, with the description of a high percentage of healthy carrier animals. Cryptococcosis is a severe disease, usually secondary to other process, especially feline immunodeficiency. In cows we refer to fungal abortion, with three main fungi implicated: Aspergillus, Candida and Zygomycetes. In some areas of our country the percentage of fungal abortion is around 10 %. A consequence of the multiple use of antibiotics in mastitis is selection of yeasts, especially those included in the genera Candida and Cryptococcus. Bovine dermatophytoses is an extensively disseminated disease in our country, with a commercial specific vaccine available. In small ruminants, Cryptococcus causes severe pneumonic processes that could be confused clinically with other conditions. An additional important question is the description of isolation of this fungus from tree leaves. In poultry, aspergillosis is a known and controlled disease, but with more importance in captive wild birds with an ecological value. In horses, we emphasize the lung infections by different fungi, specially Pneumocystis carinii, and arthritis by yeasts as consequence of wound contamination or surgery.

English Abstract↗

PubMed2000

[Present and future in the immunodiagnosis of the animal mycoses].

The problems that exist in the clinical, microbiological, and histopathological diagnosis of animal mycoses establish the necessity to investigate immunological methodologies in the diagnosis of these diseases. In this way, it may be possible to develop easy and fast techniques, allowing early detection of the disease, and efficient therapy. In our laboratory we have developed an indirect ELISA methodology to the diagnosis of aspergillosis in dog, cat, cow, sheep and birds, and dermatophytoses in dog and cat. Our results suggest this kind of technique may be useful not only in the diagnosis of animal mycosis, but in important fields as the elucidation of the fungal pathogenicity or the elaboration of effective vaccines, and with the possible application in human medicine.

English Abstract↗

PubMed1999

A randomized blinded clinical trial of two antivenoms, prepared by caprylic acid or ammonium sulphate fractionation of IgG, in Bothrops and Porthidium snake bites in Colombia: correlation between safety and biochemical characteristics of antivenoms.

A randomized blinded clinical trial was performed in 53 patients bitten by Bothrops sp. and Porthidium sp. in Antioquia and Chocó, Colombia, in order to compare the efficacy and safety of two antivenoms made of whole IgG obtained by either ammonium sulphate (monovalent anti-B. atrox) or caprylic acid (polyvalent) fractionation. Additionally, antivenoms were compared by electrophoretic and chromatographic analyses and anticomplementary activity in vitro. With a protocol of 2, 4 and 6 antivenom vials for the treatment of mild, moderate and severe envenomings, respectively, both antivenoms were equally efficient to neutralize the most relevant signs of envenoming and to clear serum venom levels in patients from the first hour and later on. Three patients with severe envenoming and initially treated with less than six vials on admission had persistent or recurrent venom antigenemia within 12-48 h. Monovalent antivenom fractionated by ammonium sulphate precipitation had higher amounts of protein aggregates and nonimmunoglobulin proteins than polyvalent antivenom fractionated by caprylic acid precipitation. Both antivenoms presented anticomplementary activity in vitro, being higher in the monovalent product. In agreement, monovalent antivenom induced a significantly higher incidence of early antivenom reactions (52%) than polyvalent antivenom (25%).

Adolescent↗

PubMed1999

Sublethal maternal pre-exposure of fish to cadmium. Effect on the survival of the newly hatched alevins.

The aim of this study was to determine the effects of the exposure of pregnant females of a viviparous teleost Cnesterodon decemmaculatus to sublethal Cd solutions on the survival of their offspring. Ovigerous females were acclimated and accomodated in aquaria containing the following solutions: artificial freshwater medium (AFW) and AFW with 25, 50 and 100 microg Cd(2+) /L (as chloride). Part of the offspring born from control females was transferred to media contain-ing 25, 50 and 100 microg/L of cadmium; the rest of the fry stayed in AFW solutions without cadmium. The offspring born from the females maintained in solutions of cadmium were transferred to aquaria with AFW, and to solutions containing metal at the same concentration as their mother. In all cases mortality was recorded daily for 168 h. The results demonstrated that the survival of newborn offspring was always related to the concentration of Cd(2+) to which they were exposed at birth, regardless of the concentration of the metal to which the mother was exposed during its pregnancy. When exposed to Cd(2+), alevins from non-exposed females showed a constant linear death rate while in those from Cd-exposed it resulted exponential.

Animals↗

PubMed1999

Hypothalamic-pituitary-adrenal axis function in patients with active rheumatoid arthritis: a controlled study using insulin hypoglycemia stress test and prolactin stimulation.

OBJECTIVE: To study the response of cortisol and of prolactin (PRL) to specific stimuli in rheumatoid arthritis (RA). METHODS: We measured the response of cortisol to insulin induced hypoglycemia and of PRL to thyrotropin releasing hormone (TRH) in 10 patients with active RA and in 10 paired control subjects. All were women with regular menstrual cycles. They had never received corticosteroids before the study. The PRL concentration was assessed by chemiluminescence immune assay and the cortisol concentration by radioimmunoassay. RESULTS: The basal serum levels of cortisol (14.47+/-2.5 microg/dl) and PRL (10.1+/-1.3 ng/ml) in the RA group were not significantly different from those of the control group (12.3+/-1.1 microg/dl and 13.7+/-2.4 ng/ml, respectively). The peak value of cortisol after hypoglycemia was comparable in both groups (25.5+/-2.4 microg/dl in RA vs. 26.0+/-1.5 ng/ml in controls). The integrated cortisol response to hypoglycemia expressed as area under the response curve (AUC) did not differ significantly in either group (1927+/-196 in RA vs. 1828+/-84 in controls). The interval-specific "delta" cortisol response was significantly higher for the 30 to 45 min interval in controls compared to patients with RA (9.8+/-0.9 microg/dl vs. 6.1+/-1.1 microg/dl; p = 0.02). The peak of PRL after TRH did not differ significantly in both groups (56.4+/-6.4 ng/ml in RA vs. 66.3+/-7.7 ng/ml in controls) and the AUC of PRL secretion after TRH was comparable in both groups (3245+/-321 vs. 4128+/-541). CONCLUSION: Our findings suggest that active RA is associated with subtle dysfunction of the hypothalamic-pituitary-adrenal glucocorticoid function and normal PRL secretion.

Adrenocorticotropic Hormone↗

PubMed1998

Comparative study of the venoms of three subspecies of Lachesis muta (bushmaster) from Brazil, Colombia and Costa Rica.

A comparative study was performed on the pharmacology and biochemistry of venoms from three subspecies of Lachesis muta (L. m. stenophrys, L. m. muta and L. m. rhombeata) from Brazil, Colombia and Costa Rica. All venoms induced lethal, hemorrhagic, edema-forming, myotoxic, coagulant and defibrinating effects, showing also proteolytic and indirect hemolytic activities. The venoms of L. m. stenophrys from Costa Rica and L. m. muta from Cascalheira, Brazil, had the highest lethal and hemorrhagic activities and the venom of L. m. rhombeata showed the highest coagulant activity, whereas no significant differences were observed in myotoxic and edema-forming activities at most of the time intervals studied. In addition, venoms showed similar electrophoretic patterns on SDS-polyacrylamide gel electrophoresis. In conclusion, despite quantitative differences in toxic and enzymatic activities, together with subtle variations in electrophoretic patterns, our results indicate that experimental envenomation by these venoms induce a qualitatively similar pathophysiological profile.

Animals↗