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Biomedical subjects

A Méndez

Publications and source records attributed to A Méndez.

At least 19 recordsLinked to original sources
PubMed2006

Study of KIR genes in tuberculosis patients.

A total of 97 patients with tuberculosis (TB) and 51 controls from Xalapa, Veracruz, Mexico, were studied for the presence and absence of killer cell immunoglobulin-like receptor (KIR) genes. The number of patients with either KIR2DL1 or KIR2DL3 differed significantly compared with the controls. However, only the difference in KIR2DL3 remained significant after correction for the number of factors analysed. We also found KIR2DS2 with its presumed C1 group ligand less prevalent in TB patients than in the control group, but this result lost significance after correction.

Adult↗
PubMed2003

The effect of the reinforcing carbon on the microstructure of pitch-based granular composites.

Carbon composites were prepared with four pitches (a commercial impregnating coal-tar pitch, two thermally treated pitches and an air-blown pitch) and four granular carbons (anthracite, graphite, green petroleum coke and foundry coke). Granular carbon/pitch proportions were optimized for each composite and differed in the characteristics of the single components. Interactions of the pitch with the granular carbons during pyrolysis and their subsequent effects on the microstructure of the final composite were monitored by light microscopy. The results show that the light texture of the matrix and the porosity of the composite depend not only on the chemical composition of the pitch but also on the specific granular carbon used as reinforcing material. The same pitch may generate different light textures depending on the characteristics of the carbon. Composites from thermally treated pitches and graphite show highly ordered matrices orientated in the direction of graphite planes. Graphite particles seem to exert a huge influence on mesophase development during the pyrolysis of the treated pitches, affecting not only the orientation of the mesophase, but also reducing the rate of mesophase formation. On the other hand, when green petroleum coke is used with the thermally treated pitches, matrices show a small size light texture, due to the high reactivity of the pitch in the presence of this granular carbon. The porosity of the composites is controlled by both the pitch and the granular carbon.

Carbon↗
PubMed2003

African swine fever and classical swine fever: a review of the pathogenesis.

This paper describes major pathogenetic mechanisms of African and Classical Swine Fever virus infections. The interactions between both viruses and the monocyte-macrophage-system result in the release of mediator molecules, which are important for the further progression of the diseases. The causes of the thrombocytopenia and the mechanisms of the haemorrhages, which are characteristic in both infections, are described. Apoptotic cell death is regarded as the predominant cause of lymphopenia in both virus infections.

African Swine Fever↗
PubMed2002

[Methicillin-resistant Staphylococcus aureus: a serious problem for the patient].

Staphylococcus Aureus Methycilin Resistant (SAMR) can be a cause of infections in patients which are difficult to treat because of their multiple resistances. For this reason, in 1999 we started a study in our Vascular Surgery Unit, to evaluate the effectivity of our stablished control measures to detect patients that were SAMR (+) carriers before discharged. During the year 2000, we repeated the same study and we observed that the precursions use of this control measures, during the first days of admission, decreased the number of SAMR (+) carriers and improved their follow-up.

Humans↗
PubMed2001

Colostomy closure using local anesthesia.

The feasibility of performing colostomy closures using local anesthesia was evaluated. The subjects comprised 14 patients: 2 with colostomies involving a mucous fistula and 12 with loop colostomies. Patients who had colostomies with mucous fistulas separated by 10cm or more were excluded from this study. All patients were graded as ASA 1 (according to the American Society of Anesthesiologists). The bowel was evaluated by colonoscopy in 6 patients and by barium enema in 8 patients. Bowel preparation was performed with Colayte and all patients were given prophylactic antibiotics. Closure of the colostomy was extraperitoneal and the time taken to perform the operation ranged from 40 to 120min. Tolerance was regarded as excellent in 9 patients, good in 3, and average in 2. There were 3 anastomotic leaks that resolved without further surgical treatment, 2 wound infections, and 1 bowel obstruction that was successfully treated with medication. Patients were discharged 2-22 days postoperatively, after a mean period of 9 days. Local anesthesia offers a safe and effective alternative to general or regional anesthesia for surgical closure of colostomies.

Adolescent↗
PubMed2001

Complete genome sequence of transmissible gastroenteritis coronavirus PUR46-MAD clone and evolution of the purdue virus cluster.

The complete sequence (28580 nt) of the PUR46-MAD clone of the Purdue cluster of transmissible gastroenteritis coronavirus (TGEV) has been determined and compared with members of this cluster and other coronaviruses. The computing distances among their S gene sequences resulted in the grouping of these coronaviruses into four clusters, one of them exclusively formed by the Purdue viruses. Three new potential sequence motifs with homology to the alpha-subunit of the polymerase-associated nucleocapsid phosphoprotein of rinderpest virus, the Bowman-Birk type of proteinase inhibitors, and the metallothionein superfamily of cysteine rich chelating proteins have been identified. Comparison of the TGEV polymerase sequence with that of other RNA viruses revealed high sequence homology with the A-E domains of the palm subdomain of nucleic acid polymerases.

Amino Acid Sequence↗
PubMed2001

Stereological study of normal and apoptotic cell populations in the adrenal gland in calves.

Morphometrical features of the adrenal gland in calves were assessed using stereological methods for normal and apoptotic cells. Adrenal glands were obtained from calves (n = 16) after they were slaughtered in a commercial abattoir. Quantitative data of nuclear size showed the highest values in the noradrenaline-storing region for all parameters, whereas the nuclei of the zona fasciculata were significantly larger than those of the other cortical regions. Data of nuclear size and shape of apoptotic cells reflected their morphometrical features; as expected, a notable decrease in the nuclear size and a more irregular shape were found in apoptosis with respect to the normal nuclei in all adrenal regions. The volume fraction data supplied the percentage of the adrenal gland occupied by each histological zone, highlighting the zona fasciculata as being the most extensive one. A significant increase in V(V)(nucl/tis), S(V)(nucl/tis), and Nv(nucl/tis) was observed in cortical regions with respect to the medullar regions. A comparison between normal and apoptotic nuclei indicated a highly significant decrease in V(V)(nucl/tis), S(V)(nucl/tis), and Nv(nucl/tis) for the apoptotic nuclei in all the adrenal zones. The apoptotic nuclei figures found in all the adrenal regions suggest that a process of cell renovation occurred in all the zones, although the higher number of apoptosis in zona reticularis is in agreement with previous results that have pointed out this zone as being a cell senescence region. The results of discriminant analyses gave the parameter required and the percentage of correct classifications for discriminating between normal nuclei, between apoptotic nuclei and between normal and apoptotic nuclei.

Adrenal Glands↗
PubMed2000

Mediastinal plasma cell tumor in a sheep.

An extramedullary plasmacytoma was found in a 10-year-old sheep. The tumor involved the mediastinum, where a 25 x 15 x 10-cm encapsulated mass was found. The lungs had multiple metastases ranging from 0.5 to 2 cm in diameter, and the portal vein contained a 10-cm-long mass. The cytologic and histopathologic analyses were consistent with a moderately differentiated plasmacytoma. The immunophenotype of the tumor cells was lambda light chain IgG+, CD79a-, and CD3-. Occasional granulomas were observed at the periphery of the mediastinal and pulmonary tumors. Microbiologic culture yielded growth of Corynebacterium from these granulomas. This is the first report of plasmacytoma in sheep. The tumor most likely arose from mediastinal lymph nodes and metastasized to the lungs and portal vein.

Animals↗
PubMed1999

Synthesis of nitric oxide in the dorsal motor nucleus of the vagus mediates the inhibition of gastric acid secretion by central bombesin.

1. Central administration of bombesin inhibits gastric acid production independently of the centrally or peripherally-acting stimuli employed. This study evaluates the role and location of the cerebral nitric oxide (NO) implicated in the inhibitory effect of central bombesin on in vivo rat gastric acid secretion, as induced by distension with 15 cm H2O, insulin (0.75 u.i. kg-1 i.p.) TRH (1.2 microg kg-1, i.c.) or pentagastrin (100 microg kg-1, i.p.). 2. The acid-inhibitory effect of i.c. bombesin (40 ng kg-1) was prevented by prior administration of L-NAME (80 microg kg-1) in the dorsal motor nucleus of the vagus (DMN). This dose of L-NAME when administered into the nucleus of the tractus solitarious (NTS) did not influence the effects of bombesin. Administration of L-arginine (400 microg kg-1) into the DMN restored the acid-inhibitory effect of i.c. bombesin in animals treated with L-NAME. 3. Microinjection of bombesin (12 ng kg-1) into the paraventricular nucleus of the hypothalamus (PvN) inhibits acid secretion stimulated by pentagastrin. This inhibitory effect was prevented by a previous injection of L-NAME (80 microg kg-1) into the DMN. 4. The release of NO in the DMN following i.c. administration of bombesin was confirmed by in vivo electrochemical detection. 5. Administration by microdialysis in the DMN of the NO-donor SNAP (25 mM in 1.5 microl min-1) into the DMN inhibits pentagastrin-stimulated gastric acid secretion. 6. The present study suggests that nNOS-containing neurons in the DMN have an inhibitory role in the control of gastric acid responses.

Animals↗
PubMed1998

Ovine cutaneous squamous cell carcinoma: immunohistochemical expression of CD3, CD4, CD8 and MHC class II antigens in the associated inflammatory infiltrate.

The immunohistochemical expression of CD3, CD4, CD8 and MHC class II antigens in the cellular inflammatory infiltrate associated with early and advanced ovine squamous cell carcinomas (OSCC), as well as actinic keratosis was analyzed. The majority of the peritumoral and intratumoral lymphocytes reacted with the anti-human CD3 polyclonal antibody. The number of CD8+ T lymphocytes increased in advanced OSCC compared with that of actinic keratosis and early OSCC, whereas the number of CD4+ lymphocytes was similar in early and advanced OSCC. Tumor cells were unreactive with the anti-MHC class II antibody, but the majority of the mononuclear cellular infiltrate expressed this antigen in early and advanced tumors.

Animals↗
PubMed1998

Comparative immunohistochemical study of stellate cells in normal canine and equine adenohypophyses and in pituitary tumours.

The presence and distribution of S100 protein (alpha and beta subunits), cytokeratin polypeptides, glial fibrillary acidic protein, neurofilaments, vimentin, neuron specific enolase, synaptophysin, HLA class II DR antigen, and pituitary hormones (prolactin, adrenocorticotropic hormone and human chorionic gonadotrophin) in stellate cells were studied immunohistochemically in four normal canine pituitary glands, five canine pituitary adenomas, two canine pituitary carcinomas and two equine pituitary adenomas (with surrounding normal glandular tissue). Stellate cells of the pars distalis and pars intermedia of canine and equine adenohypophyses showed a strong reaction with antibodies against S100 protein subunits alpha and beta. They also reacted with antibody against high and low molecular weight cytokeratins, but not with those against other intermediate filament proteins, neuroendocrine markers, the HLA-class II DR antigen or the pituitary hormones. Other populations of cells expressing both subunits of the S100 protein were polygonal cells of the pars distalis of the adenohypophysis (horse) and marginal epithelial cells of the pars intermedia of the adenohypophysis (dog and horse). Some pituitary tumours had S100-immunoreactive cells with a distribution of alpha and beta subunits that differed between the two species. Some canine tumours (one adenoma and one carcinoma) expressed only the alpha subunit, but both of the equine adenomas expressed alpha and beta protein subunits. Some of the S100-immunoreactive tumour cells reacted with RCK-102 (cytokeratins 5+8) antibody in the dog but not in the horse. The results suggested that canine and equine stellate cells of the adenohypophysis are more closely related to epithelial than to glial cells, as is the case in cattle, sheep and goats but not human beings or mice. No subpopulation of cells of bone marrow origin could be identified among canine stellate cells, as they lack MHC class II antigen. The results also suggested that the presence of S100-immunoreactive cells is more striking in canine and equine tumours than in human tumours.

Adenoma↗
PubMed1998

[A case of cortical amusia in a patient with musical ability].

CLINICAL CASE: A women who had previously had musical ability presented with bilateral embolic damage to both superior temporal convolutions. For the first few days, she had complete cortical deafness with reception aphasia. This evolved to a slight Wernicke's aphasia and reception amusia. The amusia was characterized by inability to understand lyrics and tunes, and in this patient has persisted a year and a half later. CONCLUSIONS: It is postulated that the inability to understand the words of songs is due to damage to the first left temporal convolution, whilst the amusia of tunes is due to damage to the first right temporal convolution.

Female↗
PubMed1997

Clinicopathological study of an outbreak of squamous cell carcinoma in sheep.

This paper describes the clinical and histopathological features of an outbreak of cutaneous squamous cell carcinomas in a flock of Berrichon du Cher sheep in south-western Spain. The outbreak was unusual because of the high prevalence recorded (15 to 18 per cent over the last two years) and because the majority of the lesions involved the eyelids. Adult and old sheep were the most commonly affected, and the largest numbers of cases were recorded in summer and autumn. The initial lesions were non-specific and consisted of erythema, hyperkeratosis, actinic keratosis, periocular dermatitis and conjunctivitis. The tumours grew slowly but progressively over a period of one to two years, with frequent complications by bacterial infections or secondary myiasis. Histopathological examination of the tumours revealed well-differentiated squamous cell carcinomas, surrounded by a moderate to abundant infiltrate of lymphocytes, plasma cells and macrophages. The overlying epidermis was frequently ulcerated and inflamed. The possible relationships between the high prevalence of the condition and the poorly pigmented skin of this breed, the extensive farming system employed and the exposure of the animals to ultraviolet radiation were analysed.

Animals↗