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Biomedical subjects

M Yebra

Publications and source records attributed to M Yebra.

At least 37 records · Page 2Linked to original sources
PubMed1994

Receptor tyrosine kinase signaling required for integrin alpha v beta 5-directed cell motility but not adhesion on vitronectin.

FG human pancreatic carcinoma cells adhere to vitronectin using integrin alpha v beta 5 yet are unable to migrate on this ligand whereas they readily migrate on collagen in an alpha 2 beta 1-dependent manner. We report here that epidermal growth factor receptor (EGFR) activation leads to de novo alpha v beta 5-dependent FG cell migration on vitronectin. The EGFR specific tyrosine kinase inhibitor tyrphostin 25 selectively prevents EGFR autophosphorylation thereby preventing the EGF-induced FG cell migration response on vitronectin without affecting constitutive migration on collagen. Protein kinase C (PKC) activation also leads to alpha v beta 5-directed motility on vitronectin; however, this is not blocked by tyrosine kinase inhibitors. In this case, PKC activation appears to be associated with and downstream of EGFR signaling since calphostin C, an inhibitor of PKC, blocks FG cell migration on vitronectin induced by either PKC or EGF. These findings represent the first report implicating a receptor tyrosine kinase in a specific integrin mediated cell motility event independent of adhesion.

Cell Adhesion↗
PubMed1994

[Autoimmune hemolytic anemia associated with ulcerative colitis arising after colectomy].

Autoimmune hemolytic anemia is a rare, although not exceptional, complication of ulcerative colitis. This report presents a case of this association, which is noteworthy in that the hematologic picture appeared immediately after colectomy was performed due to colonic perforation. The features of the only three reported cases in which anemia developed after colectomy are reviewed, and the role of this surgical technique in the treatment of hemolytic anemia associated with ulcerative colitis is discussed. Although colectomy does not protect patients with ulcerative colitis from the onset of hemolytic anemia, we consider that proctocolectomy should be included among the therapeutic alternatives when this association is present, especially in the case of refractory colitis.

Adult↗
PubMed1994

T lymphocytes from alcoholic cirrhotic patients show normal interleukin-2 production but a defective proliferative response to polyclonal mitogens.

T lymphocyte proliferation is a complex process involving intra- and extracellular molecules. T cell activation was studied in T lymphocytes from patients with alcoholic cirrhosis. A defective phytohemagglutinin (PHA)-induced T cell mitogenesis was observed in 60% of these patients. Likewise, their blastogenic response to anti-CD3 was also depressed (p < 0.05). However, the DNA synthesis induced by stimulation with phorbol esters (12-O-tetradecanoil-phorbol-13-acetate) + ionomycin was normal (p > 0.05). These alterations cannot be ascribed either to decreased interleukin-2 synthesis or to a defective interleukin-2 receptor expression after cellular activation. Moreover, supplementation of the PHA-stimulated T cell cultures with saturant concentrations of recombinant interleukin-2 did not normalize the hypoproliferative response of T cells from alcoholic++ cirrhotic patients. These results provide evidence that a generalized alteration in the interactions between either mitogens or interleukin-2 and their receptors can explain the T lymphocyte-defective blastogenesis found in patients with alcoholic cirrhosis.

Antibodies↗
PubMed1993

[Giant-cell myocarditis: a systemic disease? Apropos a case].

Giant cell myocarditis is a rare disease of unknown etiology, which develops as a myocardial isolated affection or associated to different diseases. Its characteristics are such as necrosis, inflammation and giant cell presence in the myocardium. We present the case of a woman who suffered of giant cell myocarditis, thymoma, myasthenia gravis, chronic lymphocytic thyroiditis, giant cell myositis, granulomatous infiltration in the lymph nodes of the hilus of the lung and hypogammaglobulinemia; multiple association that we have not found in any published medical paper and that suggest the autoimmune origin of this illness. The cardiovascular symptoms and the associated diseases are revised, and we discussed the diagnostic and therapeutic topics, pointing out the necessity to take it into account for any patient with thymoma or myasthenia gravis developing to heart failure or arrhythmias.

Agammaglobulinemia↗
PubMed1993

[Amyloidosis and sleep-inhibiting apnea. A case improved by continuous positive pressure applied via the nose].

We present a patient with primary amyloidosis and sleep-inhibiting apnea and review the only two cases for which adequate references have been made in the medical literature. The importance of a complete anamnesis on the characteristics of sleep are stressed, and it is suggests that treatment with positive pressure applied via the nose (cPAP), as in the case presented here, can mean an important symptomatic improvement in a disease with an unfortunate prognosis.

Administration, Intranasal↗
PubMed1992

Delta 9-tetrahydrocannabinol suppresses concanavalin A induced increase in cytoplasmic free calcium in mouse thymocytes.

It has been shown that delta-9-tetrahydrocannabinol (THC) suppresses thymocyte, lymph node, and splenic lymphocyte proliferation in response to a mitogenic stimulus. It has also been reported that increases occur in the cytosolic free calcium concentration (Ca2+) in mitogen treated lymphocytes. In an attempt to understand a portion of the molecular basis of the THC induced suppression of lymphocyte proliferation, we have examined the effects of THC on the Concanavalin A (Con A) induced cytosolic free Ca2+ mobilization in mouse thymocytes measured by fluorescent Ca2+ probes and spectrofluorometry. The results show that a 10 minute pretreatment with THC suppresses the normal rise in intracellular free Ca2+ in response to Con A. A THC concentration of 4 micrograms/ml (13 microM) was suppressive and the drug vehicle, DMSO, had no effect. In addition, we found that THC pretreatment did not inhibit the binding of FITC labeled Con A to the thymocytes suggesting that the drug did not interfere with lectin binding to the cell surface. To further define the nature of the Ca2+ response affected by THC, mouse thymocytes containing fura-2 were exposed to Con A either in the presence or absence of Ca(2+)-containing medium. It was observed that THC abrogated both intracellular release (measured in Ca(2+)-free medium) as well as extracellular Ca2+ influx. These results suggest that a portion of the proliferation defect in THC treated lymphocytes may be related to a drug induced inhibition of Ca2+ mobilization that normally occurs following mitogen treatment.

Aminoquinolines↗
PubMed1991

[Thalassemia minor with iron overload: genetic and clinical study of a family].

A patient with thalassemia minor (TM) is reported who ingested 80 g of alcohol/day and presented an important overload of iron with deposits and a hepatic iron ratio compatible with primary hemochromatosis. The results obtained from the study of histocompatibility antigens, clinical manifestations and family analysis discarded the possibility of two genetic diseases, beta-thalassemia and primary hemochromatosis, being concomitantly present in the same progeny. Thalassemia minor and alcoholic hepatopathy are considered as having acted together and being responsible for the iron overload. The relation between alcohol ingested, TM and iron deposits is discussed.

Adult↗
PubMed1991

Late relapse with nodular lymphoma after treatment for diffuse non-Hodgkin's lymphoma.

Histologic conversion from a low-grade non-Hodgkin's lymphoma (NHL) into a more aggressive histologic pattern is a common, well-documented event in NHL. The converse phenomenon, appearance of a low-grade, follicular NHL after treatment for diffuse, intermediate, or high-grade NHL, has only recently been recognized. The clinical, morphologic, and immunologic features of a patient in whom relapse with an indolent nodular lymphoma was noticed after combination chemotherapy for diffuse lymphoma are presented. Immunologic markers at presentation and relapse were similar. Other previously reported cases are reviewed. Implications for diagnosis and therapy as well as the pathogenesis of this unique form of conversion are discussed.

Aged↗
PubMed1991

Hepatic fibrin-ring granulomas: a clinicopathologic study of 23 patients.

Twenty-three patients with characteristic hepatic fibrin-ring granulomas were studied. Q fever accounted for 10 cases (43%), visceral leishmaniasis for five cases (22%), boutonneuse fever for two cases (9%), and toxoplasmosis, Hodgkin's disease, and allopurinol hypersensitivity for one case each (4%). The etiology remained undetermined in three cases (13%). This report broadens the range of etiologies of hepatic fibrin-ring granulomas to include boutonneuse fever and toxoplasmosis in the differential diagnosis of ring granulomas, and it could serve as a guideline to the clinician and pathologist for the most frequent categories of disease associated with this morphologic pattern.

Adult↗
PubMed1991

Interleukin 2 production in a family with systemic lupus erythematosus and a C4Q0 heterozygous inheritance.

Interleukin 2 production was studied in a family with systemic lupus erythematosus (SLE) and a C4Q0 heterozygous inheritance. Autoimmune manifestations seemed to be associated with the HLA haplotype containing the C4Q0 allele, which was shared by all four ill family members. Concentrations of interleukin 2, however, did not associate either with the haplotype or with the clinical or serological manifestations, as diminished concentrations of interleukin 2 were found in only two subjects with SLE. Thus the defect in this family seemed to be acquired rather than genetically conditioned.

Adolescent↗