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A Crespo

Publications and source records attributed to A Crespo.

At least 55 records · Page 3Linked to original sources
PubMed1994

Differential diagnosis of solid adrenal masses using adrenocortical scintigraphy.

To evaluate the diagnostic contribution of adrenal scintigraphy with 75-Se-selenomethylcholesterol in adrenal masses, 42 patients have been studied. All of them had a solid adrenal mass discovered on computed tomography (seven bilateral). None of the patients showed any symptoms or clinical signs that might indicate the existence of adrenal dysfunction. Twenty-nine of them had known extra-adrenal primary malignant disease. Forty-nine adrenal tumours were detected with an average size of 3.29 cm (range 1.5-12 cm). Eighteen lesions showed increased uptake of radiocholesterol on the side of the adrenal mass, all of which were either proven to be benign, or behaved in a benign fashion. Twelve lesions showed normal uptake (10 in the benign group and one lung carcinoma metastasis), all but one (2.5 cm) being smaller than 2 cm. Decreased uptake was observed in 20 lesions (15 metastases, two nonfunctional adrenal carcinomas, one myelolipoma and two tuberculous infectious lesions). Adrenocortical scintigraphy provides functional information about adrenal masses and is useful in differentiating between benign and malignant lesions.

Adrenal Gland Neoplasms↗
PubMed1994

A case of complete Carney's syndrome.

The triad of gastric leiomyoblastoma, paraganglioma, and pulmonary chondroma was first described by Carney in 1977. The authors report a case of a patient with gastric leiomyosarcoma, multiple pulmonary chondromata, and paraganglioma. This represents a complete form of Carney's triad. The paraganglioma was identified with I-123 MIBG.

3-Iodobenzylguanidine↗
PubMed1993

Interleukin-1 beta-specific partial agonists defined by site-directed mutagenesis studies.

Monocyte-derived interleukin 1 (IL-1) mediates a wide range of biological effects including destruction of the cartilage matrix in articular diseases such as rheumatoid and osteoarthritis. To elucidate further the relationships between protein structure and biological activities, we have analyzed the sequence of several IL-1 polypeptides using the algorithm of Parker, the hydrophobic cluster analysis method and published structural data. This led us to identify several residues that seemed to be strictly topologically conserved, with respect to identifiable secondary structures features, although this was not readily apparent from sequence alignments. We performed site-directed mutagenesis on some of these conserved residues, as well as on those predicted to occur in external loops of the polypeptide. Human IL-1 beta mutant polypeptides were expressed in Escherichia coli in soluble form and purified to homogeneity by anion-exchange and gel-filtration chromatography. Their biological effects (binding to EL4-6.1 murine thymocytes, Raji human B cells and rabbit chondrocytes cells, lymphocyte activation, neutral protease induction, proteoglycan degradation and synthesis) have been determined. Among the 20 IL-1 beta mutant polypeptides we present here, four showed a markedly reduced activity in cartilage matrix assays without any significant change in their binding to the cartilage matrix cells (chondrocytes). Furthermore, some of these mutants were specific partial agonists of the effects of IL-1 on connective tissue since they have a low affinity for thymocytes.

Amino Acid Sequence↗
PubMed1993

Single topical application of human recombinant basic fibroblast growth factor (rbFGF) promotes neovascularization in rat cerebral cortex.

Basic fibroblast growth factor (bFGF) is a morphogenic, chemotactic, mitogenic, and angiogenic peptide found within the central nervous system (CNS) with potent neurotrophic effects. A potential role in ischemia-induced vascular growth has been suggested for bFGF. In this study, we show that single, topical administration of human recombinant basic fibroblast growth factor (rbFGF) in the rat cerebral cortex promotes capillary overgrowth and might mimic the angiogenic response observed after brain ischemia. The implication of this finding for the therapeutic use of basic FGF in angiogenic therapy is discussed.

Animals↗
PubMed1993

Characterization of a human NK1 tachykinin receptor in the astrocytoma cell line U 373 MG.

The human NK1 tachykinin receptor in the astrocytoma cell line U 373 MG was characterized using selective agonists and antagonists described for this receptor in the rat. Specific [3H]substance P binding sites were present on cell homogenates, whereas [3H]neurokinin A or [3H]-senktide binding sites were absent. The binding was saturable and reversible. The binding of [3H]substance P was inhibited by very low concentrations of [L-Pro9]substance P and [Sar9,Met(O2)11]substance P; septide was approximately 1,000-fold less potent. The most potent peptide antagonist was trans-4-hydroxy-1-(1H-indol-3-ylcarbonyl)-L-prolyl-N-methyl-N-(phe nylmethyl)-L- tyrosineamide. The rank order of potency for the nonpeptide antagonists was (S,S)-CP 96,345 > (+/-)-CP 96,345 > (+/-)-2-chlorobenzylquinuclidinone > (R,R)-CP 96,345 > RP 67580 > RP 68651. In [3H]-inositol-labeled cells, substance P stimulated phosphatidylinositol turnover. A good correlation was found when the abilities of NK1 receptor agonists for stimulating inositol phosphate production and for inhibiting [3H]substance P binding were compared. Similarly, the binding and functional assays were well correlated for the antagonists. As a result of its high sensitivity and selectivity, the U 373 MG cell line thus appears an excellent tool for investigating the pharmacology of the human NK1 receptor.

Astrocytoma↗
PubMed1993

Diabetic foot infections: scintigraphic evaluation with 99Tcm-labelled anti-granulocyte antibodies.

Thirty-eight lesions found by physical and/or radiological examination in 25 patients with long-term diabetes mellitus were studied in order to evaluate the clinical utility of immunoscintigraphy using 99Tcm-labelled anti-granulocyte monoclonal antibodies (MAb BW 250/183) for the diagnosis of infectious pathology in diabetic foot. All the patients underwent three-phase bone scintigraphy with 740 MBq 99Tcm-methylene disphosphonate. Immunoscintigraphy was performed 4 and 24 h after administration of 500 MBq of the labelled antibody by planar selective views. Uptake intensity was scored 0 to 4 (0 = normal, 1 = mildly increased, 2 = moderately increased, 3 = intense, 4 = very intense) when compared with adjacent or contralateral uninvolved bone marrow and soft tissue. Several projections were performed and anatomical references of bone scan were used to determine whether the lesion involved the bone or soft tissue. Definitive diagnoses were 15 osteomyelitis, 14 soft tissue lesions (nine cellulitis and five noninfected ischaemic or trophic wounds), and nine degenerative bone disease. 99Tcm-granulocyte scintigraphy showed increased uptake in seven soft tissue lesions, in four of which exclusively soft tissue involvement was demonstrated by scintigraphy. Only one false negative scintigraphic finding was observed (chronic osteomyelitis). No abnormal anti-granulocyte antibody uptake was observed in degenerative lesions. Based on our observations, immunoscintigraphy with 99Tcm-MAb BW250/183 has a sensitivity of 93% in the diagnosis of osteomyelitis involving diabetic patients' feet. Although it is feasible to distinguish exclusive soft tissue involvement, this is still the main cause of misdiagnosis in current clinical practice.

Adult↗
PubMed1988

Monoclonal antibodies against synovial collagenase: use for immunopurification and characterization of the latent and active enzyme.

Monoclonal antibodies have been produced against porcine synovial collagenase which recognize both the active enzyme and its inactive precursor. These antibodies inhibited the collagenolytic activity of collagenase, but not its activity with a synthetic peptide substrate. The antibodies were also able to recognize human synovial, human skin fibroblast and human chondrocyte collagenase but not the enzyme from human granulocytes. One of the monoclonal antibodies was successfully used for the immunopurification of the porcine enzyme and these experiments led to the demonstration of an endogenous activator of procollagenase in the synovial cell culture medium.

Animals↗
PubMed1984

Regulation of energy metabolism in Trypanosoma (Schizotrypanum) cruzi epimastigotes. I. Hexokinase and phosphofructokinase.

Hexokinase (ATP: hexose 6-phosphotransferase, E.C.2.7.1.1) and phosphofructokinase (ATP:fructose-6-phosphate 1-phosphotransferase, E.C.2.7.1.11), two key regulatory enzymes of the glycolytic pathway in vertebrate cells, have been isolated and partially purified from Trypanosoma (Schizotrypanum) cruzi epimastigotes. Both enzymes are associated with particles sedimentable at 105 000 X gav for 1 h and have a high degree of latency; they can be solubilized by sonication. Hexokinase catalyses the phosphorylation of a series of monosaccharides at the following relative rates: D-glucose (100) congruent to D-fructose (97) greater than 2-deoxy-D-glucose (72) congruent to mannose (69) greater than 2-amino-D-glucose (63) greater than 3-O-methyl-D-glucose (21). Very little or no phosphorylating activity was found for D-galactose, N-acetyl-2-amino-D-glucose or 1-alpha-methyl-D-glucose. D-Glucose phosphorylation at fixed ATP concentration follows simple Michaelis-Menten kinetics with Km = 40 microM and Vmax = 440 nmol min-1 mg-1 protein. D-Mannose, 2-deoxy-D-glucose and N-acetyl-2-amino-D-glucose act as competitive inhibitors of glucose phosphorylation, suggesting a single kinase. Mg2+-ATP is the preferred phosphoryl donor, ITP and GTP being much less effective. T. cruzi hexokinase is not inhibited by D-glucose 6-phosphate, or by any of the following compounds (2 mM):D-fructose 6-phosphate, D-fructose 1,6-diphosphate, D-glucose 1,6-diphosphate, phosphoenol pyruvate, L-malate and citrate. Phosphofructokinase displays simple Michaelis-Menten kinetics with no evidence of sigmoidicity with respect to D-fructose 6-phosphate at all ATP concentrations tested, giving a Km of 1.31 mM and Vmax = 400 nmol min-1 mg-1 protein at optimal ATP levels. With respect to ATP, the enzyme exhibits Michaelis-Menten kinetics at low concentration (less than 1 mM) of the substrate (Km = 40 microM at 5 mM MgCl2, pH 7.4). A moderate inhibition is observed at high ATP levels (70% of maximal activity at 2 mM). GTP can substitute for ATP as the phosphoryl donor (Km = 79 microM under the same conditions), but produces only very small inhibitory effects at high concentrations. 5'-AMP activates the enzyme by decreasing its Km with respect to D-fructose 6-phosphate without affecting Vm. Other well-known regulators of the activity of this enzyme in procaryote and vertebrate systems such as citrate, phosphoenol pyruvate, ammonium and phosphate ions have no effect in T. cruzi.

Animals↗
PubMed1984

Localization of a neutralization epitope of foot-and-mouth disease virus using neutralizing monoclonal antibodies.

Neutralizing monoclonal antibodies raised against intact foot-and-mouth disease virus reacted with intact particles and with isolated VP1 from different strains from the same subtype. Prior treatment of the virus with either trypsin or with arginine-specific protease abolished recognition of both the virus and of VP1, suggesting the presence of a neutralization epitope in the central region of VP1 cleaved by these two enzymes. A synthetic peptide analogue of part of this region showed poor reactivity, however, with neutralizing antibody.

Animals↗