Biomedical subjects

M I Lopez

Publications and source records attributed to M I Lopez.

5 recordsLinked to original sources

PubMed1992

Intravitreal silicone and fluorosilicone oils: pathologic findings in rabbit eyes.

The effects of medical-grade intraocular silicone and commercial-grade fluorosilicone oils were studied in rabbit eyes. The experimental model consisted of lensectomized and vitrectomized eyes that did not undergo further treatment (Group 1), and three groups of lensectomized and vitrectomized eyes that were injected intravitreously 3 months earlier with medical-grade silicone oil of 1000 cs (Group 3), and 10,000 cs (Group 4). The silicone oil-injected eyes developed proliferative membranes. The fluorosilicone oil caused an intravitreous inflammatory reaction with vacuolated macrophages present around the oil that may have been due to the higher concentration of low-molecular-weight components found in the oil.

Animals↗

PubMed1991

Age influence on mononuclear phagocyte system Fc-receptor function in poststreptococcal nephritis.

The Fc-receptor function of the mononuclear phagocyte system (MPS) was examined in 41 children and adult patients, by measuring the clearance of IgG-sensitized, 51Cr-labeled erythrocytes. The Fc-receptor-mediated clearance observed in patients (mean +/- SE) was not significantly different as compared to the control group of similar age distribution. However, the immune clearance time was significantly age-correlated in both groups (acute poststreptococcal glomerulonephritis, APSGN, r = 0.39, p less than 0.05; control r = 0.63, p less than 0.01). The magnitude of the Fc-specific immune clearance and the serum creatinine were also significantly correlated (r = 0.59; p less than 0.01). Circulating immune complexes (as measured by the C1q and conglutinin ELISA) did not correlate with immune clearance, which remained stable in longitudinal studies. Age-related changes in MPS Fc-receptor function could explain, at least in part, prognostic differences between children and adult patients with APSGN.

Adolescent↗

PubMed1991

Idiopathic membranous nephropathy, associated with HLA-DRw3 and not related to monocyte-phagocyte system Fc receptor dysfunction, in father and son.

Familial idiopathic membranous nephropathy, an immune-complex-associated glomerulopathy, has not been previously reported in father and son, despite its striking immunogenetic correlation, especially with HLA-DR3. As a dysfunction of the monocyte-phagocyte system (MPS), it has been observed linked to DR3 antigen, so we studied the MPS Fc receptor function in a father and his son with a histologically proven membranous nephropathy, associated with the haplotype A9-B35-DR3-DQw2. The Fc receptor function of the MPS was examined by measuring the clearance of IgG-sensitized, 51Cr-labeled erythrocytes and by measuring the ability of isolated monocytes to ingest autologous red blood cells coated with IgG anti-Rh (D) antibody. Immune clearance and in vitro phagocytosis was normal in both patients and not related to their levels of immune complexes (as measured by ELISA C1q and Conglutinin solid-phase binding assay). This report suggest that genetic factors may play an important role in the development of membranous nephropathy, and it seems not to be related to a dysfunction of MPS as measured by these tests.

Adolescent↗

PubMed1990

Decrease in mean platelet survival time in acute poststreptococcal glomerulonephritis (APSGN).

In an attempt to study further the possible participation of platelets in the pathogenesis of acute poststreptococcal glomerulonephritis (APSGN), we studied the platelet survival time, as an index of platelet activation, in 22 patients with APSGN. Mean platelet survival time was computed from the disappearance of radioactivity from blood, sampled serially after injection of autologous 51Cr-labelled platelets. C1q solid phase ELISA and conglutinin (K) solid phase ELISA were used to measure the serum levels of immune complexes. The platelet survival time in APSGN patients was 113 +/- 10 h vs 197 +/- 10 h in the control group (p less than 0.001); 68% of the patients had a shortened platelet survival, lower than 95% confidence limit. There was a significant increase in the platelet survival in the six patients that were studied after recovery from acute nephritic syndrome. There was no significant association between the mean platelet times survival and CICs (circulating immune complexes). Similarly, no significant correlation was found between the mean platelet lifespan and the severity of the glomerular disease, as assessed by the serum creatinine level and the proteinuria. These results support evidence of platelet activation and consumption in APSGN and we suggest that this activation occurs in the glomeruli capillary wall, due to platelet-vascular wall interaction.

Acute Disease↗

PubMed1989

Presence of circulating immune complexes in the classic form of hemolytic uremic syndrome: a constant finding.

In an attempt to further study the possible contribution of circulating immune complexes (CIC) in the pathogenesis of the classic form of hemolytic uremic syndrome, 9 patients were studied during the acute phase of the diseases. C1q solid-phase ELISA and conglutinin solid-phase ELISA, were used to measure the levels of immune complexes. All 9 were positive in one or both assays. No correlation was found between the levels of CIC and the clinical severity of the disease. The constant finding of positive CIC in these patients might represent an epiphenomenon, point out the postinfectious nature of this disease but also suggest a possible pathogenic role.

Antigen-Antibody Complex↗