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Biomedical subjects

J Varela

Publications and source records attributed to J Varela.

At least 37 records · Page 2Linked to original sources
PubMed1995

Peroxisomal copper, zinc superoxide dismutase. Characterization of the isoenzyme from watermelon cotyledons.

The biochemical and immunochemical characterization of a superoxide dismutase (SOD, EC 1.15.1.1) from peroxisomal origin has been carried out. The enzyme is a Cu,Zn-containing SOD (CuZn-SOD) located in the matrix of peroxisomes from watermelon (Citrullus vulgaris Schrad.) cotyledons (L.M. Sandalio and L.A. del Río [1988] Plant Physiol 88: 1215-1218). The amino acid composition of the enzyme was determined. Analysis by reversed-phase high-performance liquid chromatography of the peroxisomal CuZn-SOD incubated with 6 M guanidine-HCl indicated that this enzyme contained a noncovalently bound chromophore group that was responsible for the absorbance peak of the native enzyme at 260 nm. The amino acid sequence of the peroxisomal CuZn-SOD was determined by Edman degradation. Comparison of its sequence with those reported for other plant SODs revealed homologies of about 70% with cytosolic CuZn-SODs and of 90% with chloroplastic CuZn-SODs. The peroxisomal SOD has a high thermal stability and resistance to inactivation by hydrogen peroxide. A polyclonal antibody was raised against peroxisomal CuZn-SOD, and by western blotting the antibody cross-reacted with plant CuZn-SODs but did not recognize either plant Mn-SOD or bacterial Fe-SOD. The antiSOD-immunoglobulin G showed a weak cross-reaction with bovine erythrocytes and liver CuZn-SODs, and also with cell-free extracts from trout liver. The possible function of this CuZn-SOD in the oxidative metabolism of peroxisomes is discussed.

Amino Acid Sequence↗
PubMed1995

Nitric oxide and prostaglandin systems inhibition on the isolated perfused human placenta from normal and preeclamptic pregnancies.

Isolated human placental cotyledons from normal (NG) and preeclamptic gestants (PG) were perfused in vitro, and the effect of N omega-nitro-L-arginine (L-NA, 100 microM), methylene blue (MB, 50 microM), and indomethacin (INDO, 10 microM), on resting perfusion pressure and on the 5-hydroxytryptamine (5-HT)-induced vasoconstriction was established. In the HG, L-NA and MB increased resting perfusion pressure (p < 0.001) and INDO had no significant effect on resting pressure. In the PG, these agents did not significantly modify resting perfusion pressure. In the PG, 5-HT (10 microM-1 microM) caused greater maximal increases in perfusion pressure than in NG. In the NG, L-NA greatly enhanced the 5-HT-induced pressure, however INDO attenuated this effect. In the PG, L-NA did not modify significantly the 5-HT-induced response, but INDO reduced this response. These results suggest that basal release of nitric-oxide but not of vasodilator prostanoids may contribute to the low resting vascular tone in the NG and attenuates the strong vasoconstrictor effect induced by 5-HT. Impairment of action of nitric oxide could contribute to the enhanced pressor response to 5-HT observed in the PG.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1994

Primary structure of Lep d I, the main Lepidoglyphus destructor allergen.

The most relevant allergen of the storage mite Lepidoglyphus destructor (Lep d I) has been characterized. Lep d I is a monomer protein of 13273 Da. The primary structure of Lep d I was determined by N-terminal Edman degradation and partially confirmed by cDNA sequencing. Sequence polymorphism was observed at six positions, with non-conservative substitutions in three of them. No potential N-glycosylation site was revealed by peptide sequencing. The 125-residue sequence of Lep d I shows approximately 40% identity (including the six cysteines) with the overlapping regions of group II allergens from the genus Dermatophagoides, which, however, do not share common allergenic epitopes with Lep d I.

Allergens↗
PubMed1993

Cervical pregnancy. A case report.

Cervical pregnancy is one of the most dangerous forms of ectopic pregnancy. This condition is frequently unsuspected before evaluation of the uterus and it is characterized by massive bleeding during that procedure. We report a case of cervical ectopic pregnancy diagnosed by ultrasound at 11 weeks' gestation and managed by emergency hysterectomy for severe hemorrhage occurring immediately after removal of the placenta.

Abortion, Spontaneous↗
PubMed1992

High-level synthesis in Escherichia coli of shortened and full-length human acidic fibroblast growth factor and purification in a form stable in aqueous solutions.

A highly efficient expression for human acidic fibroblast growth factor (aFGF) has been assembled to direct the synthesis of both shortened and native full-length aFGF. The full-length aFGF-154 form of the protein had not been produced before in Escherichia coli by genetic engineering, and is obtained with its initiator methionine removed. The high production of the aFGF allows one to circumvent the use of reversed-phase chromatography (RPC) during the purification procedure. Here, it is shown that RPC, routinely used to obtain pure preparations of recombinant aFGF, modifies its chemical and physical properties in an unfavorable manner.

3T3 Cells↗
PubMed1992

Single-step purification on DEAE-sephacel of recombinant polypeptides produced in Escherichia coli.

We describe a method for the purification of recombinant proteins based upon the selective interaction of the choline-binding domain of the pneumococcal murein hydrolase and tertiary amines. Proteins of interest, fused to the binding domain by a peptide linker, containing the cleaving sequence recognized by blood coagulation factor Xa, can either be assayed for biological activities in vitro and in vivo or have the binding moiety removed to yield a totally unmodified form, suitable for clinical and functional studies. The method can also be applied to the production of low molecular mass peptides. The principle of the technique is illustrated with acidic fibroblast growth factor and with a neuropeptide-like fragment of ten amino acids contained within its sequence.

3T3 Cells↗
PubMed1991

Magnesium and potassium ions on tone and reactivity of human placental chorionic veins.

1. In vitro studies were undertaken to investigate the effects of external potassium [K+]0 2.4-7.1 mM and magnesium [Mg2+]0 0-4.8 mM concentration on human chorionic veins basal tone and on serotonin (5-HT)-induced contractions. 2. The higher the [Mg2+]0, the less the basal tension developed in isolated chorionic veins, irrespective of the [K+]0. 3. The EC50 value to 5-HT was enhanced by increases in [Mg2+]0, whereas the ability of 5-HT to induce a maximal contraction was attenuated. 4. The rightward shift of the concentration-response curves and reduced Emax response, observed when the concentration of [Mg2+]0 was raised, indicate a non-competitive antagonism of [Mg2+]0 with 5-HT. 5. The lack of an effect of [K+]0 on the EC50 and Emax values for 5-HT suggest that in this tissue the affinity of 5-HT for 5-HT receptors does not involve potassium. 6. These results suggest that basal tone and 5-HT-induced contractions of human chorionic vascular smooth muscle cells appear to be highly sensitive to alterations in extracellular Mg2+.

Chorionic Villi↗
PubMed1991

Fascioliasis: findings in 15 patients.

The clinical and radiological features of 15 cases of fascioliasis are reported. Pleural effusion, associated with pulmonary infiltrates or ascites, was observed in two patients. Computed tomography (CT) was the most useful imaging method, showing small nodules and linear tracks within the liver parenchyma which were hypodense on non-enhanced scans, remaining hypodense or becoming isodense with normal liver after contrast medium administration. After successful treatment lesions decreased in number and size and finally disappeared or calcified. Lesions increased or remained unchanged when treatment failed to control the disease.

Adolescent↗
PubMed1990

Laminar periostitis and multiple osteonecrosis in systemic lupus erythematosus.

Bone affectation in systemic lupus erythematosus (SLE) is caused both by the disease itself and by the treatment used. We report the case of a woman diagnosed of SLE, who, in the course of her illness, develops multiple aseptic osteonecrosis (AON) and laminar periostitis, radiologically compatible with the diagnosis of hypertrophic osteoarthropathy (HOA), with no evidence of acropaquia. In this case, the patient shows all the risk factors involved in the pathogenesis of the development of ischemia in bone microcirculation.

Adult↗
PubMed1989

Prenatal ultrasonographic diagnosis of thoracopagus conjoined twins.

Conjoined twins are a rare obstetric event occurring 1/50,000 to 1/60,000 deliveries as a result of incomplete fission of the embryonic disc before the third week of pregnancy. They belong to the monochorionic-monoamniotic type of monozygotic twins and are classified according to the area of union, the most common site being the chest and upper abdomen (thoracopagus). Reported are two cases of thoracopagus twins in which the diagnosis was made prenatally by ultrasound in the second trimester of pregnancy. The most significant ultrasound findings included the demonstration of a single cardiac activity, the inability to separate the fetal bodies at their ventral portion, and a face-to-face fetal position. The pregnancies were allowed to continue until term with no significant prenatal complications, and an elective cesarean section was performed to avoid a traumatic delivery. In both cases the infants died during the first week of life because of cardiorespiratory insufficiency. The ultrasound criteria for the antenatal diagnosis of conjoined twins are reviewed, concluding that the careful ultrasound examination of all identified sets of twins, specially in those cases in which no separating membrane is demonstrated, is the cornerstone in making the prenatal diagnosis. In addition, ultrasound plays a crucial role not only in the diagnosis, but also in establishing the degree of conjoining, which is essential for planning an appropriate obstetrical and perinatal management.

Adult↗
PubMed1979

[Eosinophilic pleural effusion during the course of a giardiasis. Report of a case (author's transl)].

A case of eosinophilic pleural effusion with coincidental intestinal infestation by Giardia lamblia is reported. After reviewing the possible causes of this type of pleuritis no clinical or laboratory data were obtained which could explain this condition, excepting the giardiasis, in the course of which there is no bibliographic reference in this sense. After the parasitosis had been treated with metronidazole the parasitologic negativization coincided with the disappearance of the pleural effusion. A review of the etiologies described in relation to eosinophilic pleural effusion and of the factors involved in the movilization of eosinophils, especially those which have a relationship with parasitosis, was carried out. Parasitosis may be capable of determining immune reactions with release of eosinophilotactic substances. The fact that the lung of experimental animals has been shown to be a suitable tissue for the release of factors with eosinophilotactic activity, could indicate that this organ has a special reactive capacity and probably, together with it, a closely related structure such as the pleura could have it too.

Eosinophils↗