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Biomedical subjects

C Saavedra

Publications and source records attributed to C Saavedra.

44 records · Page 3Linked to original sources
PubMed1990

Junin virus replication in peripheral blood mononuclear cells of patients with Argentine haemorrhagic fever.

To study the relationship of Junin virus (JV) to populations of peripheral blood mononuclear cells (PBMC) from patients with Argentine Haemorrhagic Fever (AHF), blood samples were obtained during the acute period of disease and cultured as total, adherent, and non-adherent cell populations. JV was sequentially sought in these cell populations by using an Infectious Centre (IC) assay, whereas free JV in the supernatants was evaluated by plaque formation. IC were obtained in cultures of total PBMC from 8 out of 19 patients. Maximum numbers of IC showed high variation among patients, ranging from 3 to 410 IC per 10(6) viable PBMC. In contrast, IC were sporadically demonstrated in the non-adherent cell population. The release of JV into culture supernatants was detected only in total PBMC cultures, thus in the presence of macrophages. These results demonstrate that circulating monocytes (macrophages) are targets for JV replication contributing to the viral spread in the acute phase of AHF.

Acute Disease↗
PubMed1988

Affinity labeling of Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase with the 2',3'-dialdehyde derivative of ATP.

Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase [ATP:oxaloacetate carboxy-lyase (transphosphorylating), EC 4.1.1.49] is completely inactivated by the 2',3'-dialdehyde derivative of ATP (oATP) in the presence of Mn2+. The dependence of the pseudo-first-order rate constant on reagent concentration indicates the formation of a reversible complex with the enzyme (Kd = 60 +/- 17 microM) prior to covalent modification. The maximum inactivation rate constant at pH 7.5 and 30 degrees C is 0.200 +/- 0.045 min-1. ATP or ADP plus phosphoenolpyruvate effectively protect the enzyme against inactivation. oATP is a competitive inhibitor toward ADP, suggesting that oATP interacts with the enzyme at the substrate binding site. The partially inactivated enzyme shows an unaltered Km but a decreased V as compared with native phosphoenolpyruvate carboxykinase. Analysis of the inactivation rate at different H+ concentrations allowed estimation of a pKa of 8.1 for the reactive amino acid residue in the enzyme. Complete inactivation of the carboxykinase can be correlated with the incorporation of about one mole of [8-14C]oATP per mole of enzyme subunit. The results indicate that oATP can be used as an affinity label for yeast phosphoenolpyruvate carboxykinase.

Adenosine Triphosphate↗
PubMed1985

Retention of herpes simplex virus type II sequences in bglII n-transformed cells after co-transfection with a selectable marker.

Transformation of mammalian cells by total u.v.-inactivated herpes simplex virus II (HSVII) or cloned fragments thereof (BglII n, BglII C) has been complicated both by a low efficiency of oncogenic transformation and the disappearance of viral DNA and/or viral products initially detected in the transformed cell lines. In an attempt to effect a stable integration of BglII n and to elucidate the role of HSVII in oncogenic transformation, we have co-transfected NIH 3T3 cells with pAG60, a plasmid which confers resistance to the G418 antibiotic, and plasmids containing either BglII n in its entirety (pNB2) or one of five subfragments of BglII n. Several isolated clones exhibit a transformed phenotype as expressed by rapid growth in low serum concentrations and colony formation in soft agar. We have obtained a markedly reduced frequency of biochemical transformants when co-transfecting pNB2 in comparison with the numbers obtained when cotransfecting the five subfragments. Furthermore, a greater proportion of subfragment-transfected colonies contain viral DNA, and in higher copy number, than observed in the pAG60/pNB2 clones. We have also found viral DNA to be more stably integrated in the subfragment-transfected clones than in the pNB2-transfected clones.

Animals↗
PubMedDate not supplied

[Long-term follow-up of 166 surgically treated patients with congenital hip dislocation].

UNLABELLED: 166 patients with congenital dislocation of the hip, ranging from 10 months to 5 years old, were operated between 1958 and 1971. 140 patients were women (84%) and 26 patients were men (16%). 96 patients had unilateral and 70 patients had bilateral dislocation; that makes a total of 236 dislocated hips. 61 patients with bilateral hip dislocation were operated simultaneously on both hips. All the patients were treated with adductor tenotomy and open reduction through Smith Petersen incision with section or elongation of the psoas tendon. The postoperative immobilization consisted in a period of one month pelvic toecast followed by 2 plaster casts with abduction rod during 3 to 5 months. The postoperatory follow-up ranged from 9 years to 26 years, 2 months; average 14 years, 5 months. The clinical evaluation comprises pain, hip mobility, gait and muscle power. RESULTS: excellent 138 (59%); good 66 (28%); fair 29 (12%); and poor 3 (1%). The radiological evaluation considered: Mose; acetabular femoral head index; Wiberg's CD-angle; cervico-diaphysiary angle and radial quotient. RESULTS: normal 5 (2%); excellent 44 (19%); good 78 (33%); subtotal 54%; fair 90 (38%), and poor 19 (8%). Complications (hips); infections 12 (5%); 3 of them deep ones (1%); residual subluxation 19 (8%); reluxation 1 (0.5%). Isquemic necrosis Grade II of Tönnis 31 (13%); Grade III 2 (1%) and Grade IV 1 (0.5%).

Adolescent↗