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Biomedical subjects

P Muñoz

Publications and source records attributed to P Muñoz.

At least 91 records · Page 5Linked to original sources
PubMed1999

Optimizing the balance between false positive and false negative error probabilities of confirmatory methods for the detection of veterinary drug residues.

GC-MS data on veterinary drug residues in bovine urine are used for controlling the illegal practice of fattening cattle. According to current detection criteria, peak patterns of preferably four ions should agree within 10 or 20% from a corresponding standard pattern. These criteria are rigid, rather arbitrary and do not match daily practice. A new model, based on multivariate modeling of log peak abundance ratios, provides a theoretical basis for the identification of analytes and optimizes the balance between the avoidance of false positives and false negatives. The performance of the model is demonstrated on data provided by five laboratories, each supplying GC-MS measurements on the detection of clenbuterol, dienestrol and 19 beta-nortestosterone in urine. The proposed model shows a better performance than confirmation by using the current criteria and provides a statistical basis for inspection criteria in terms of error probabilities.

Animals↗
PubMed1999

Visual perception of the Moiré effect.

The perception of Moiré fringes is studied with two different tests for binocular and monocular conditions. The results are negative for binocular conditions, and positive for the monocular case when afterimages are used.

Adult↗
PubMed1999

Kaplan Award 1998. Epidemiology of chronic daily headache in the general population.

BACKGROUND AND OBJECTIVES: Although chronic daily headache, mainly transformed migraine, is an important reason for consultation in headache clinics, its actual prevalence is unknown. This study analyzes the prevalence of the different types of chronic daily headache in an unselected population. METHODS: A questionnaire exploring headache frequency was distributed to 2252 unselected subjects. Those having headache 10 or more days per month were given a headache diary and were seen by a neurologist who classified their headaches. The varieties of chronic daily headache were classified according to the second revision of IHS criteria proposed by Silberstein et al published in Neurology 1996;47:871. RESULTS: The questionnaire was returned by 1883 subjects (83.5%). One hundred thirty-five admitted to headache 10 or more days per month. Chronic daily headache criteria were fulfilled by 89 individuals (4.7%). Eighty were women. Forty-two (47.2% of subjects with chronic daily headache and 2.2% of all subjects) had chronic tension-type headache. Analgesic overuse was found in 8 (17%). Transformed migraine was diagnosed in 45 (50.6% of subjects with chronic daily headache and 2.4% of all subjects). Fourteen (31.1%) individuals with this form of chronic daily headache overused ergots or analgesics. The remaining 2 cases in this series met the criteria of new daily persistent headache. No one was diagnosed as having hemicrania continua. CONCLUSIONS: Almost 5% of the general population (9% of women) suffers from chronic daily headache, the proportion of chronic tension-type headache and transformed migraine being quite similar. Less than one third overuse analgesics. The prevalence of chronic daily headache subtypes shown here differs from data obtained from headache clinics, emphasizing that caution is needed in extrapolating data from specialized units to the general population.

Adolescent↗
PubMed1999

Micro-organisms responsible for osteo-articular infections.

Identification of the aetiological agents responsible for bone and joint infections requires either hard to obtain specimens that are easy to interpret, or easy to obtain specimens of difficult interpretation. Isolates obtained by blood cultures, arthrocentesis, or trephine or surgical biopsy bone samples are usually clinically significant. In contrast, samples obtained from sinus tracts or through open wounds are very often easy to obtain but difficult to interpret. Micro-organisms such as Staphylococcus epidermidis are the most common cause of infections around prosthetic joint materials but are usually of little significance when obtained from the sinus tract of a patient with chronic osteomyelitis of the tibia without osteosynthesis. Other micro-organisms to be interpreted with caution include Corynebacterium spp. and Enterococcus spp. The most important families of antimicrobial agents and their utility in bone and joint infections are briefly reviewed at the end of the chapter. Bone and joint infections require long-term antimicrobial therapy based on the correct diagnosis and the appropriate selection of antimicrobial treatment.

Arthritis, Infectious↗
PubMed1999

Acute and chronic adult osteomyelitis and prosthesis-related infections.

Both acute and chronic osteomyelitis are causes of rising concern, mainly because of the increasing number of traumatic accidents, the appearance of new groups of patients at risk, the widespread use of prosthetic devices and the emergence of new patterns of antimicrobial resistance. Classification systems, clinical features and risk factors will be reviewed. Diagnosis is usually clinical and microbiological, but imaging techniques such as plain radiography, radionuclide imaging, computed tomography and magnetic resonance imaging are commonly used. Decisions regarding the best imaging modality can be challenging and should reflect the location of the suspected infection and any associated illnesses or bone disorders. Osteomyelitis is characteristically recurrent, needs multiple surgical interventions and is resistant to short courses of therapy. The application of more precise diagnostic techniques and the availability of non-toxic, highly efficacious oral antimicrobial agents frequently permit a long-term ambulatory approach. The optimal length of therapy has not been established.

Acute Disease↗
PubMed1999

Comparative studies on carbohydrates of several myxosporean parasites of fish using lectin histochemical methods.

A histochemical study using lectin methods was performed on myxosporean parasites from vastly different fish hosts from marine and fresh waters. Six biotinylated lectins were used (WGA, SBA, BS-I, Con-A, UEA-I and SNA). The binding pattern of Con-A and WGA revealed the presence of mannose and/or glucose, and N-acetyl-D-glucosamine respectively, in polar capsules and valves of most of the myxosporea assayed. Thus, chitin may be present in polar capsules and/or valves of myxosporean spores. The BS-I binding pattern showed the presence of alpha-D-galactose and/or N-acetyl-D-galactosamine residues in polar capsules of Kudoa sp., Zschokkella mugilis Sitjà-Bobadilla et Alvarez-Pellitero, 1993 and Leptotheca sp., and in the valves of the latter. Scarce amounts of N-acetyl-D-galactosamine and/or alpha-D-galactose were demonstrated by SBA binding in Sphaerospora dicentrarchi Sitjà-Bobadilla et Alvarez-Pellitero 1992, Leptotheca sp. and Kudoa sp. valves, and in Leptotheca sp. polar capsules. The UEA-I staining indicated the absence of alpha-L-fucose in all the myxosporea assayed except in Leptotheca sp. N-acetylneuraminic acid was detected with SNA in the polar capsules and sporoplasms of Polysporoplasma sparis Sitjà-Bobadilla et Alvarez-Pellitero, 1995 and in the polar capsules and valves of Kudoa sp. These results indicate that, although Myxosporea may have conserved carbohydrate structures, some of them can show significantly different binding patterns, which may be useful in diagnostic and functional studies.

Animals↗
PubMed1998

Myocardial Epstein-Barr virus-associated cardiac smooth-muscle neoplasm arising in a cardiac transplant recipient.

Epstein-Barr virus-associated smooth muscle proliferations have been reported in immunosuppressed patients with acquired immunodeficiency syndrome and after organ transplantation. We report here a case of a histologically benign case arising in a 48-year-old male who had received immunosuppressive therapy 4 years earlier, after cardiac transplantation. In the necropsy performed for unrelated reasons, an incidental left intramyocardial tumor was discovered. The presence of Epstein-Barr virus was confirmed by EBER-1 in situ hybridization and polymerase chain reaction. To the best of our knowledge, this is the first case of an Epstein-Barr virus-associated smooth muscle proliferation arising in the heart after cardiac transplantation and should be added to the potential complications of this kind of procedure.

Aortic Aneurysm, Abdominal↗
PubMed1998

Rhodococcus equi infection in transplant recipients: case report and review of the literature.

BACKGROUND: Rhodococcus equi is an opportunistic pathogen that usually causes infection in immunocompromised hosts, mainly human immunodeficiency virus-positive patients, yet solid organ transplant recipients may be affected as well. Infections in this group of patients have not been sufficiently analyzed. METHODS: We report an R equi pneumonia in a heart transplant recipient and review another 11 cases. RESULTS: Infection appeared a mean of 49 months (range 1-180) after transplantation. Lung was primarily involved in 10 cases (83.3%). The remaining two cases presented with a paravertebral abscess and a purulent pericarditis. Invasive techniques were necessary to reach the diagnosis in nine cases. One patient healed with surgical resection of the lesion; the remaining 11 received antimicrobial agents. Six of them required additional surgical treatment. Three patients died. CONCLUSIONS: Clinicians should consider R equi when evaluating a solid organ recipient with an asymptomatic lung nodule. Microbiology laboratories should be alerted in these cases because it could be mistaken for a contaminant diphtheroid and will not respond to the standard empirical therapy.

Actinomycetales Infections↗
PubMed1998

Immunohistochemical characterization of a polyclonal antibody against Sphaerospora dicentrarchi (Myxosporea: Bivalvulida), a parasite from sea bass (Dicentrarchus labrax L.) (Teleostei: Serranidae).

Rabbit antibody was raised against Sphaerospora dicentrarchi, a histozoic parasite of sea bass (Dicentrarchus labrax L.). Light and electron immunohistological staining were used to characterize its specificity and possible reactivity toward other fish parasites. In light immunohistochemistry the polar capsules and valves of the S. dicentrarchi spores appeared strongly stained, whereas developmental stages were not. Electron microscopic histochemistry revealed intense labeling in valves and some developmental stages. Cross-reaction was observed with all the myxosporean parasites assayed, even with those belonging to other genera. Polar capsules of all the myxosporean species except Polysporoplasma sparis were the main structures stained by the polyclonal antibody. These observations could reveal the existence of conserved antigenic epitopes in polar capsules of different Myxosporea.

Animals↗
PubMed1998

Pneumonia after heart transplantation: a multi-institutional study. Spanish Transplantation Infection Study Group.

A multiinstitutional study of 307 heart transplant recipients was carried out to determine the clinical, radiographic, and prognostic characteristics, the incidence, and the etiology of pneumonias in the first year after transplantation. There were 21.1 cases of pneumonia per 100 heart transplantations. Seventy-five percent of the cases occurred in the first trimester. Eighty-two causal agents were identified, of which 60% were opportunistic, 25% were nosocomial, and 15% were community-acquired. The most frequent isolates were cytomegalovirus (20), Aspergillus species (13), and Pneumocystis carinii (11). Hemoptysis occurred more frequently in aspergillus pneumonias than in other pneumonias (54% vs. 6%, respectively; P < .05); aspergillus pneumonia was the only type of pneumonia during which cavitated nodules were noted on thoracic radiographs. The overall mortality rate was 30.8%; the independent factors of a poor prognosis were aspergillus infection (relative risk [RR], 7.4; 95% confidence interval [CI], 5.8-9.1) and bilateral pulmonary infiltrates (RR, 10; 95% CI, 8.5-11.4).

Adult↗
PubMed1998

Hypersensitivity of Ku-deficient cells toward the DNA topoisomerase II inhibitor ICRF-193 suggests a novel role for Ku antigen during the G2 and M phases of the cell cycle.

Ku antigen is a heterodimer, comprised of 86- and 70-kDa subunits, which binds preferentially to free DNA ends. Ku is associated with a catalytic subunit of 450 kDa in the DNA-dependent protein kinase (DNA-PK), which plays a crucial role in DNA double-strand break (DSB) repair and V(D)J recombination of immunoglobulin and T-cell receptor genes. We now demonstrate that Ku86 (86-kDa subunit)-deficient Chinese hamster cell lines are hypersensitive to ICRF-193, a DNA topoisomerase II inhibitor that does not produce DSB in DNA. Mutant cells were blocked in G2 at drug doses which had no effect on wild-type cells. Moreover, bypass of this G2 block by caffeine revealed defective chromosome condensation in Ku86-deficient cells. The hypersensitivity of Ku86-deficient cells toward ICRF-193 was not due to impaired in vitro decatenation activity or altered levels of DNA topoisomerase IIalpha or -beta. Rather, wild-type sensitivity was restored by transfection of a Ku86 expression plasmid into mutant cells. In contrast to cells deficient in the Ku86 subunit of DNA-PK, cells deficient in the catalytic subunit of the enzyme neither accumulated in G2/M nor displayed defective chromosome condensation at lower doses of ICRF-193 compared to wild-type cells. Our data suggests a novel role for Ku antigen in the G2 and M phases of the cell cycle, a role that is not related to its role in DNA-PK-dependent DNA repair.

Animals↗
PubMed1998

Stimulation of membrane serine-threonine phosphatase in erythrocytes by hydrogen peroxide and staurosporine.

Indirect evidence has suggested that K-Cl cotransport in human and sheep erythrocytes is activated physiologically by a serine-threonine phosphatase. It is activated experimentally by H2O2 and by staurosporine, a kinase inhibitor. Activation by H2O2 and staurosporine is inhibited by serine-threonine phosphatase inhibitors, suggesting that the activators stimulate the phosphatase. The present study shows that sheep and human erythrocytes contain membrane-associated as well as cytosolic serine-threonine phosphatases, assayed from the dephosphorylation of 32P-labeled glycogen phosphorylase. In cells from both species, the relatively low sensitivity of the membrane enzyme to okadaic acid suggests it is type 1 protein phosphatase. The cytosolic phosphatase was much more sensitive to okadaic acid. Membrane-associated phosphatase was stimulated by both H2O2 and staurosporine. The results support earlier conclusions that the membrane-associated type 1 phosphatase identified here is regulated by phosphorylation and oxidation. The results are consistent with the phosphatase, or a portion of it, being responsible for activating K-Cl cotransport.

Animals↗
PubMed1998

Effect of ethanol ingestion on renal regulation of water and electrolytes.

Ethanol may alter the homeostasis of water and electrolytes before the occurrence of liver damage able to explain these disorders. How the kidney may become involved in water diuresis or sodium and potassium retention has not been well elucidated. During the last decade, an increasing body of evidence has guided interest toward the relevance of the biochemical basis of ethanol-induced injury to the kidney. Multiple functional abnormalities of renal tubules may be associated with ethanol-induced changes in membrane composition and lipid peroxidation of these epithelial cells. Ethanol interferes with the carrier function by decreasing (Na+K)-ATPase activity, but this activity is enhanced by chronic exposure. Recently, it was reported that ethanol oxidation by the kidney is favored in chronic ethanol-treated rats, thereby suggesting a pathogenic role for acetaldehyde in the nephrotoxic effect of ethanol ingestion. Also, increased reactive oxygen species, partly generated from acetaldehyde oxidation, may contribute to the occurrence of oxidative stress. The pathophysiology of renal regulation of water and electrolytes of alcoholic disease is analyzed on the basis of recent advances in our knowledge concerning the biochemical effects of ethanol on the kidney.

Alcohol Drinking↗