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Biomedical subjects

A Lopez

Publications and source records attributed to A Lopez.

At least 145 records · Page 8Linked to original sources

Pemphigus foliaceus and pemphigus vulgaris autoantibodies react with the extracellular domain of desmoglein-1.

Pemphigus foliaceus is associated with an autoimmune response against desmoglein-1; however, the fine specificity of these autoantibodies and the role that they play in pathogenesis have not yet been elucidated. In an attempt to develop a system to facilitate the detection and characterization of this antigen/antibody system, recombinant human desmoglein-1 was expressed in COS-1 cells, a mammalian epithelial cell line. The desmoglein-1 transgene product was shown to be expressed on the surface of the COS-1 cells in the appropriate transmembrane orientation. All pemphigus foliaceus sera (endemic form, n = 24; nonendemic form, n = 7) reacted strongly with nonpermeabilized desmoglein-1-transfected cells, exhibiting a punctate cell-surface staining pattern. This reactivity against the desmoglein-1 ectodomain was predominantly an IgG4-restricted response and was calcium dependent. Ten of 18 pemphigus vulgaris sera also reacted with the extra-cellular domain of recombinant desmoglein-1. Use of this eukaryotic expression system should greatly facilitate further characterization of the anti-desmoglein-1 autoimmune response associated with pemphigus foliaceus and pemphigus vulgaris and may aid in determining its pathogenic relevance.

Animals↗

Administration of lipid-emulsion versus conventional amphotericin B in patients with neutropenia.

OBJECTIVE: To evaluate the usefulness of a 20% lipid emulsion as a delivery system for amphotericin B (1 mg/mL) administered over 1 hour to patients with neutropenia with hematologic malignancies compared with amphotericin B (0.1 mg/mL) administered in dextrose 5% solution over the same time. DESIGN: A prospective, comparative, randomized, labeled study. SETTING: Hematology unit, pharmacy service, university general hospital. PARTICIPANTS: Twenty patients with neutropenia with hematologic malignancies and proven or suspected fungal infections, 10 in the fat emulsion group (group 1) and 10 in the dextrose 5% group (group 2). MAIN OUTCOME MEASURES: Clinical tolerance (i.e., fever, shaking chills, nausea, blood pressure, pulse rate) and biologic tolerance (i.e., urea, creatinine, sodium, potassium). RESULTS: Clinical tolerance was comparable in both groups although amphotericin B in fat emulsion was better tolerated. Medication for symptoms related to the administration of amphotericin B was given in 6 cases in group 1 and in 8 cases in group 2. There was a statistically significant difference in the urea concentrations between the 2 groups (p = 0.023); there was an observed increase between the initial and the final serum urea (56.8 mg/d in group 1, 79.8 mg/dL in group 2). Statistically significant differences in creatinine serum concentrations (84.9 mumol/L in group 1, 123.8 mumol/L in group 2) (p = 0.047) were found. No differences were found in the antifungal efficacy of the treatment. However, as amphotericin B was started in the majority of cases (75%) as empiric treatment for fever unresponsive to antibiotic therapy, it is difficult to compare the efficacy of both preparations. CONCLUSIONS: The clinical tolerance of lipid-emulsion infusions is similar to that of conventionally administered amphotericin B therapy. Renal toxicity appears to be decreased when the drug is administered in a fat emulsion. This type of preparation permits the reduction of the volume and the time of administration for amphotericin B therapy.

Adolescent↗

Quantification of pneumothorax size on chest radiographs using interpleural distances: regression analysis based on volume measurements from helical CT.

OBJECTIVE: The aim of this study was to define the relationship between interpleural distance measurements on an erect posteroanterior chest radiograph and pneumothorax size as measured by helical CT in a series of patients. SUBJECTS AND METHODS: Twenty pneumothoraces from 19 patients (10 males, nine females) were analyzed. Most pneumothoraces were on the right side (n = 16). The etiology was spontaneous in seven patients and iatrogenic in thirteen. All patients underwent an erect inspiratory posteroanterior radiograph and a helical CT scan of the thorax on the same visit to the radiology department. The interpleural distance was measured at three locations and the figures added together. Following helical CT of the thorax, the percentage pneumothorax size was calculated by drawing regions of interest around the relevant hemithorax and lung on 10-mm reconstructed slices. A scattergram of the sum of interpleural distances in centimeters versus percentage pneumothorax size was plotted. RESULTS: Analysis of results showed that percentage pneumothorax size could be calculated by the formula Y = 4.2 + [4.7 x (A + B + C)], r = .98, p < .0001. CONCLUSION: This study identified a formula for accurately calculating percentage pneumothorax size as determined by helical CT from an erect posteroanterior radiograph. Using this formula with the clinical status of the patient should more easily identify patients requiring active intervention.

Adolescent↗

Flow cytometry in the diagnosis of cancer.

Flow cytometry has rapidly expanded from basic research to clinical laboratories mainly due to its unique characteristics regarding cell analysis. Among the clinical uses of flow cytometry cancer represents one of the most relevant. Several applications of flow cytometry can currently be applied to the study of cancer, including the detection of tumour cell DNA aneuploidy, the analysis of tumour cell proliferation and the immunophenotyping of leukemias. Although standardized flow cytometry protocols for these applications are scanty, the clinical value has been clearly established. The presence of DNA aneuploidy and a high proportion of S-phase tumour cells have been associated with tumour malignancy and a poor prognosis. The immunophenotype of leukaemia is of great help both for the diagnosis and classification of chronic lymphoproliferative disorders and acute leukaemias, especially in acute lymphoblastic leukemia cases and the M0, M3-variant, M6 and M7 acute myeloblastic leukaemia subtypes. In addition, it allows the identification of relatively rare leukemia cases such as the biphenotypic and the Nk-cell lineage leukemias. The development of flow cytometry is continuously bringing new applications into the clinical laboratory in the area of cancer diagnosis.

Flow Cytometry↗

Flow cytometric DNA analysis of fine-needle aspirates of prostatic benign lesions.

Fine-needle aspiration samples from 54 consecutive patients suffering from prostatic benign lesions were analyzed for both cytological diagnosis and DNA cell content, by means of standard cytological criteria and flow cytometry, respectively. Of these patients, 13 displayed prostatitis: three being classified as acute prostatitis, 7 as chronic and 3 as granulomatosous prostatitis. All cases had a diploid DNA cell content, with a mean percentage of S-phase cells of 1.8 +/- 2.7%. Although no major differences were detected between patients with and without prostatitis, the former group had a slightly higher proportion of S-phase cells (1.4 +/- 2.2% vs 2.7 +/- 3.7%). Moreover, within those patients with prostatitis, acute prostatitis cases showed the highest proliferation rates although differences did not reach statistical significance.

Biopsy, Needle↗

[Clinical features, diagnosis, and treatment of tumor lesions arising in the adrenal gland].

Between 1981 and 1993, 14 patients with tumoral adrenal disease were diagnosed and treated in the Urology Services of both Hospitals. Nature of the adrenal disease was functional in 8 patients (two carcinomas and six pheochromocytomas) and non-functional in the rest (three carcinomas, two adenomas and one myelolipoma). Reference is made to the clinical manifestations and laboratory tests related to hormonal activity, depending on whether the tumour is functional or non-functional, chromaffin or non-chromaffin. Patients with functional carcinomas had Cushing's syndrome, with very clear virtilization signs. Urine 17-hydroxycorticosteroid, 17-cetosteroides and cortisol were all increased, same as plasma cortisol. Patients with pheochromocytomas had hypertension and headaches (six patients), sweating (five patients), anxiety (four patients) and loss of weight (two patients). All of them had increased urine vainillylmandelic acid and catecholamines. Clinical signs and symptoms of non-functional tumours were related to bulk growth and size (in the three carcinomas), and sometimes was highly anodyne, or even absent (in the two adenomas and the myelolipoma), the cause of discovery being accidental during an ultrasound examination. An analysis is made of the different imaging diagnostic procedures performed, such as IVU (performed in 13 patients) with a 38.4% resolutory power; ultrasound (performed in 11 patients) with an 81.8% resolution; CAT (performed in 6 patients) with a 100% resolution capacity and arteriography (performed in 3 patients) with a 100% resolution power, although patients had previously undergone ultrasound and CAT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗

Is the length of the calcarine sulcus associated with the size of the human visual cortex? A morphometric study with magnetic resonance tomography.

PURPOSE: To determine whether the length and depth of the calcarine sulcus are associated and can be used for estimating the size of the primary visual area (area 17) and other regions in MR images of the human occipital lobe. METHODS: The length and depth of the calcarine sulcus and the projection areas of the mesial surface of the occipital lobe and of the total hemisphere were measured in MR images of 23 healthy subjects. RESULTS: A higher variability of the size of the projection area of the mesial surface of the occipital lobe compared with that of the remaining part of the hemisphere is found. The projection area of the mesial cortical surface of the occipital lobe is correlated with the length of the calcarine sulcus, but both parameters are not correlated with the depth of the calcarine sulcus and, therefore, also not with the size of the part of area 17 buried in the sulcus. CONCLUSION: The size of area 17 cannot be estimated by the length of the calcarine sulcus in MR images. Depth and length of the calcarine sulcus grow independently in the human brain. Different degrees of folding may cause the variability of architectonic areas.

Adolescent↗

Lipid domains and lipid/protein interactions in biological membranes.

In the fluid mosaic model of membranes, lipids are organized in the form of a bilayer supporting peripheral and integral proteins. This model considers the lipid bilayer as a two-dimensional fluid in which lipids and proteins are free to diffuse. As a direct consequence, both types of molecules would be expected to be randomly distributed within the membrane. In fact, evidences are accumulating to indicate the occurrence of both a transverse and lateral regionalization of membranes which can be described in terms of micro- and macrodomains, including the two leaflets of the lipid bilayer. The nature of the interactions responsible for the formation of domains, the way they develop and the time- and space-scale over which they exist represent today as many challenging problems in membranology. In this report, we will first consider some of the basic observations which point to the role of proteins in the transverse and lateral regionalization of membranes. Then, we will discuss some of the possible mechanisms which, in particular in terms of lipid/protein interactions, can explain lateral heterogenities in membranes and which have the merit of providing a thermodynamic support to the existence of lipid domains in membranes.

Animals↗

A mutation of the common receptor subunit for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor, and IL-5 that leads to ligand independence and tumorigenicity.

The cytokines interleukin-3, interleukin-5, and granulocyte-macrophage colony-stimulating factor bind with high affinity to a receptor complex that contains a ligand-specific alpha-chain and a common beta-chain, h beta c. We report here the isolation of a mutant form of h beta c, from growth factor-independent cells, that arose spontaneously after infection of a murine factor-dependent hematopoietic cell line (FDC-P1) with a retroviral h beta c expression construct. Analysis of this h beta c mutation shows that a small (37 amino acid) duplication of extracellular sequence that includes two conserved sequence motifs is sufficient to confer ligand-independent growth on these cells and lead to tumourigenicity. Because this is a conserved region in the cytokine receptor superfamily, our results suggest that the large family of cytokine receptors has the capacity to become oncogenically active.

Amino Acid Sequence↗

Influence of obstacles on lipid lateral diffusion: computer simulation of FRAP experiments and application to proteoliposomes and biomembranes.

Fluorescence Recovery After Photobleaching experiments were simulated using a computer approach in which a membrane lipid leaflet was mimicked using a triangular lattice obstructed with randomly distributed immobile and non-overlapping circular obstacles. Influence of the radius r and area fraction c of these obstacles and of the radius R of the observation area on the relative diffusion coefficient D* (Eq. (1)) and mobile fraction M was analyzed. A phenomenological equation relating D* to r and c was established. Fitting this equation to the FRAP data we obtained with the probe NBD-PC embedded in bacteriorhodopsin/egg-PC multilayers suggests that this transmembrane protein rigidifies the surrounding lipid phase over a distance of about 18 A (approximately equal to two lipid layers) from the protein surface. In contrast, analysis of published diffusion constants obtained for lipids in the presence of gramicidin suggests that in terms of lateral diffusion, this relatively small polypeptide does not significantly affect the surrounding lipid phase. With respect to the mobile fraction M, and for point obstacles above the percolation threshold, an increase in R led to a decrease in M which can be associated with the existence of closed domains whose average size and diffusion properties can be determined. Adaptation of this model to the re-interpretation of the FRAP data obtained by Yechiel and Edidin (J Cell Biol (1987) 115:755-760) for the plasma membrane of human fibroblasts consistently leads to the suggestion that the lateral organization of this membrane would be of the confined type, with closed lipid domains of approximately equal to 0.5 microns 2 in area.

Bacteriorhodopsins↗

Transrectal fine needle aspiration biopsy of the prostate combining cytomorphologic, DNA ploidy status and cell cycle distribution studies.

Fine needle aspiration (FNA) cytology of the prostate is becoming a common diagnostic procedure, and DNA flow cytometry (FCM) data have been shown to correlate with the pattern of evolution of prostatic carcinoma, thus emphasizing the importance of assessing both parameters together. The aim of the present paper is to analyze the presence of DNA aneuploidy, cell cycle distribution and their relationship with the cytologic grade in transrectal fine needle aspiration prostate biopsies from 78 consecutive patients. Herein we studied the DNA ploidy status, the cell cycle distribution and their relationship with cytologic grade in transrectal FNA biopsies of the prostate from 78 consecutive patients -47 benign hyperplasias and 31 carcinomas- as analyzed by a reproducible FCM method for single cell suspension preparations, data acquisition and analysis. The presence of DNA aneuploidy was detected in 39% of the carcinomas and it was found to be a specific marker for prostatic carcinoma since all benign hyperplasia cases were diploid. Moreover, the incidence of DNA aneuploidy increased progressively from well-differentiated to moderately-differentiated and poorly-differentiated carcinomas (p = 0.005). Regarding cell cycle distribution, carcinomas displayed a higher proportion of both S-phase (p = 0.0003) and G2/M-phase (p = 0.0006) cells with respect to benign hyperplasias. Aneuploid cases also showed a greater proliferation rate as compared to the diploid carcinomas, regardless of their cytopathologic grade (p = 0.00001). Despite the fore-mentioned results, these correlations were far from being absolute, suggesting that combined assessment of these parameters should give additional information for the clinical management of prostatic disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy, Needle↗

A multicentre study of the hospital care of 1500 patients with myelomeningocele.

The purpose of this paper is to describe the medical attention that is given to patients affected by myelomeningocele in Spain. We have used information extracted from the 'Multicentre study of patients suffering from spina bifida in Spain'. This material was collected between 1986 and 1988 from experiences with 1500 patients all over our country. 52.9% of the patients were male, and 47% female, and of the total number, 72.2% were under 15 years of age. Most of these patients attended public hospitals (78.5%) and on average each one had been admitted about seven times. The cost of hospitalisation of the sample has been assessed. Urology, orthopaedic surgery and rehabilitation are the specialties most involved. The most frequent complications were those related to the urinary system (66.1%).

Adolescent↗