Biomedical subjects

Alberto J Monserrat

Publications and source records attributed to Alberto J Monserrat.

5 recordsLinked to original sources

PubMed2006

Effects of intraosseous implantation of silica-based bioactive glass particles on rat kidney under experimental renal failure.

The aim of the present study is to evaluate the effects of intraosseous implantation of silica-based bioactive glass (BG) particles on rat kidney under experimental renal failure. The animals are assigned to one of the two groups: renal failure (RF) and renal failure + bioactive glass (RF + BG). Particles of melt-derived 45S5 BG are implanted in the marrow of one tibia of each animal in the RF + BG group. The animals are killed 24 h and 14 days postimplantation. The RF + BG group exhibits a statistically significant increase in serum urea 24 h postimplantation. The tibiae of the RF + BG group are resected and embedded in methyl-methacrylate resin. Ground sections are analyzed by light microscopy and energy-dispersive X-ray (EDX) analysis. The presence of silicon, calcium, and phosphorus is evaluated in the BG particles. A 55% reduction in silicon content is observed at 14 days postimplantation as compared with that at 24 h.Light microscopy analysis reveals lesions in kidney parenchyma. Hyperplasia associated with nuclear vacuolization in the tubules and a marked thickening of the basal membrane are observed in the renal cortex of the RF + BG animals killed at 24 h postimplantation, but not in those at 14 days. The present results demonstrate reversible renal cell injury in rats exposed to intraosseous implantation of silica-based BG particles under experimental RF.

Animals↗

PubMed2006

Ocular lesions and experimental choline deficiency.

Previous studies have shown ocular haemorrhages in choline-deficient rats. The aim of this paper is to study further the relationship between ocular and renal lesions and biochemical alterations in rats fed a choline-deficient diet. Fifty one weanling male Wistar rats, were divided into two groups. Thirty one of them were fed a choline-deficient diet and the rest was fed a choline-supplemented diet ad libitum. Animals from both groups were killed between the fifth and the eighth day. Urea, creatinine and homocysteine concentrations in blood were determined. Eyes were used for light microscopy study; high resolution light microscopy and the study of the retina as "rétine a plat". Kidneys were studied by light microscopy. Choline-supplemented rats did not show ocular or renal lesion. Choline-deficient rats that showed renal lesions, tubular or cortical necrosis, did not always have ocular changes. There were no ocular changes in the only choline-deficient rat without renal lesion. The ocular changes consisted mainly in haemorrhage in both cameras and ciliary and vitreous bodies. Correlations between ocular and renal lesion (r = 0.72, p < 0.0001, CI 95%: 0.48-0.86); ocular lesion and creatinine (r = 0.86, p < 0.0001, Cl 95%: 0.72-0.93) and ocular lesion and urea (r = 0.70, p < 0.0001, Cl 95%: 0.44-0.85) were positive. Choline-deficiency induces ocular haemorrhagic lesions after the development of renal necrosis. The ocular pathology could be due to the immaturity of the ocular vasculature at this age. The hyaloid, choroid and retinal system are involved.

Analysis of Variance↗

PubMed2004

Mild hyperhomocysteinemia promotes renal hemodynamic dysfunction without histopathologic changes in adult rats.

BACKGROUND: Hyperhomocysteinemia is able to promote glomerular damage and generate tubulointerstitial lesions. These findings were reported in rats with unilateral nephrectomy or in weanling rats with normal function, two experimental models that are exposed to other concomitant vascular risk factors. The aim of this work is to study whether mild hyperhomocisteinemia per se can induce renal histopathologic changes in adults rats with normal renal function at either 10 or 44 weeks of hyperhomocysteinemia. METHODS: Two months old male Wistar rats (N= 52) were randomly allocated to either a normal control (N= 26) or hyperhomocysteinemic (N= 26) group. Control and hyperhomocysteinemic groups had free access to either tap water or homocysteine thiolactone 50 mg/kg/day, during 10 or 44 weeks. Plasma homocysteine levels were determined by a high-performance liquid chromatography (HPLC) method. Glomerular filtration rate (GFR) and renal plasma flow (RPF) were calculated from inulin and sodium para-aminohippurate (PAH) clearance determinations. Structural renal changes were investigated in kidneys fixed by perfusion. Histopathologic and morphometric analysis were carried out by standard methods. RESULTS: Plasma total homocysteine levels were 53% (10 weeks) and 56% (44 weeks) higher in hyperhomocysteinemic group compared to the control group. GFR and RPF were significantly lower in hyperhomocysteinemic than in control group. The histopathologic and morphometric studies did not show any differences between the control and hyperhomocysteinemic rats at 10 or 44 weeks. CONCLUSION: The present results show that mild hyperhomocysteinemia is able to induce renal functional and biochemical alterations in male adult rats that are not associated with renal histopathologic changes.

Animals↗

PubMedDate not supplied

Sequential histochemical studies of neuronal lipofuscin in human cerebral cortex from the first to the ninth decade of life.

The typical and most consistent physico-histochemical properties of lipofuscin granules, such as autofluorescence, sudanophilia, acid-fastness, PAS-reactivity, and lectin reactivities for diverse saccharide moieties have been generally detected in tissue specimens of old humans and animals. The purpose of this study was, therefore, to explore possible sequential variations of each of these properties in cortical neurons of the left cerebral temporo-parietal areas from individuals dying from the first to the ninth decade. Autofluorescence was studied with an ad hoc equipped microscope, sudanophilia was evaluated by Oil-red-O (ORO) staining, acid-fastness by long Ziehl-Nielsen reagent, PAS reactivity by the periodic-acid-Schiff reagent before and after diastase treatment, and the saccharide moieties by the use of a commercial kit of seven different biotinylated lectins. In the specimen from a 5-year-old child, lipofuscin granules were detected in less than 5% of the cortical neurons, but these granules already showed golden-yellow autofluorescence, sudanophilia, acid-fastness and PAS-reactivity. From the second to the ninth decade of life, perikaryal lipofuscin granules were found in practically all cortical neurons with apparent agewise increases in the intensity of sudanophilia and PAS-reactivity, but with variable acid-fastness expression. Surprisingly, however, no saccharide residues were detected by lectin histochemistry before the fifth decade of life. First detected saccharide was mannose in specimens from the fifth decade of life, and at later decades acetyl galactosamine, sialic acid and lactose were also found. Although, the reasons for the absence of lipofuscin affinity for the seven lectins used in this study in the cortical neurons of young and middle-aged individuals are presently unknown, these unexpected findings suggested important evolutionary changes of biogenesis and composition of the age-pigment.

Journal Article↗

PubMedDate not supplied

Differential lectin histochemical studies on lipofuscin (age-pigment) and on selected ceroid pigments.

The persistent indiscriminate use of the term lipofuscin for the pigments encountered in pathological conditions, and which should be most properly termed ceroid pigments, is still creating unnecessary conceptual and nomenclature problems, and a great deal of confusion. While both the age-dependent lipofuscin and the pathologically formed ceroid pigments have somewhat similar physical and histochemical properties, sufficient differences to properly identify these two types of pigments are presented in this communication. In addition, because little is known on the saccharide components of lipofuscin and ceroid pigments in situ, we have in recent years explored the lectin binding characteristics of lipofuscin in human and rats, as well as in diverse ceroid pigments experimentally induced in rats. Our lectin histochemical results showed qualitative and quantitative differences in the saccharide composition between human cerebral neurolipofuscin and the intra and extracellular ceroid pigment of human atheromas, as well as, between rat lipofuscin and the ceroid pigments induced in these animals.

Journal Article↗