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Benedicto de Campos Vidal

Publications and source records attributed to Benedicto de Campos Vidal.

10 recordsLinked to original sources
PubMed2006

Optical anisotropy of alcian blue-stained acid glycosaminoglycans.

Optical anisotropy as dispersion of birefringence (DB) (birefringence studied for light of different wavelengths) and linear dichroism (LD) (selective absorption of polarized light) in stained substrates reflects their macromolecular orientation states. Birefringence interference colors of alcian blue (AB)-stained glycosaminoglycans (GAG) and glycoconjugates observed with polarization microscopy have been found to vary, although their staining characteristics under unpolarized light are practically the same. We investigated the optical anisotropy of GAG-AB and some glycoconjugate-AB complexes used as standards, to provide a basis for interpreting results for AB-stained materials in situ. Filamentous preparations of hyaluronic acid (HA), chondroitinsulfates, proteoglycans, and a mucus sulfoglycoconjugate were studied. Anomalous DB (birefringence sign changing with the wavelength of the incident light) was generally observed, but LD was seen only in the AB-HA complex. LD simultaneous to anomalous DB characteristics on the AB-HA complex were assumed to be caused by a maximally oriented helical conformation of the HA. For the other AB-GAG studied, the optical anisotropic characteristics were suggestive of some degree of folding of their chains into a tertiary structure. The profiles of the anomalous DB curves for the AB-stained sulfoglycoconjugate differed from those of the other materials, probably due to different organization of its dye-binding sites.

Alcian Blue↗
PubMed2006

Identification of elastic fibers and lamellae in porcine pericardium and aorta by confocal, fluorescence and polarized light microscopy.

Pericardial connective tissue has been used to construct bioprostheses to repair various types of injuries, including aortic wall repairs. The arrangement and the distribution of elastic and collagen staple fibers are related directly to the biomechanical properties of the tissue and thus determine the choice tissue for the construction of bioprostheses. Although elastic fibers can be visualized using several histochemical methods, the specificity and mechanism of binding involved remain to be clarified. In this work, we compared the elastic net of the porcine pericardial matrix with that of the aortic wall using 1-anilino-8-naphthalene sulfonate (ANS) and dansyl chloride (DCl) as fluorescent probes and the permanganate-bisulfite-toluidine (PBT) method. Polarized light and fluorescence microscopy were simultaneously used to analyze the tissues. Some samples also were examined using confocal microscopy. Aorta and pericardium treated with ANS and DCl showed elastic fibers and lamellae with an intense blue fluorescence. When stained with the PBT method, the aortic elastic lamellae were clearly metachromatic and, under polarized light, they showed a greenish birefringence. DCl provided clearer fluorescent labelling of elastic fibers when examined using confocal microscopy.

Anilino Naphthalenesulfonates↗
PubMed2006

New biocompatible highly purified collagen gel for therapeutic renal artery embolization.

OBJECTIVES: To evaluate the effectiveness and safety of a new purified collagen gel with specific properties for renal artery embolization in an experimental model in dogs. METHODS: The new gel was prepared from type I bovine tendon collagen, highly purified to eliminate immunogenicity, and reconstituted through extensive dialysis in distilled water without the addition of glutaraldehyde. The study was conducted on 16 mongrel dogs that underwent random embolization of the renal artery. The dogs were divided into two groups: group 1 was killed after 2 days and group 2 after 21 days. The abdominal organs, lungs, and muscles of the posterior limbs were studied in detail and samples were taken for an anatomic-pathologic analysis. RESULTS: After embolization, uniform parenchymatosus ischemia and loose perirenal adhesions without significant volumetric changes were observed in group 1. A microscopic study revealed acidophilus amorphous and birefringent emboli filling the lumen of the renal artery and extending into the arterioles. The glomeruli and tubules showed early signs of diffused necrosis. In group 2, microscopic examination revealed endothelial proliferation around the emboli that had closely adhered to the arterial wall, with signs of fibroblastic proliferation within the emboli. In both groups, the abdominal organs, lungs, and muscles of the posterior limbs did not show signs of collagen migration. CONCLUSIONS: Purified collagen gel effectively embolized the renal artery. The absence of collagen migration to other organs and posterior limbs suggests that this material can be safely used for organ embolization.

Animals↗
PubMed2005

Chromatin supraorganization and extensibility in mouse hepatocytes following starvation and refeeding.

BACKGROUND: The effect of 48 h of starvation and of 48 h of refeeding subsequent to starvation on chromatin supraorganization and extensibility was studied in hepatocytes from adult mice. METHODS: Methods used involved topochemical assays, image analysis, gravity action, and polarization microscopy. RESULTS: Starvation increased the chromatin packing states, especially in areas of noncondensed chromatin, and induced drastic decreases in concanavalin A reactivity due to nuclear matrix glycoproteins and the frequency of nuclei with chromatin extensibility under gravity. Changes in chromatin packing state were accompanied by shifts of nuclear areas of part of the nuclear population to smaller values but did not affect the respective Feulgen-DNA amounts except for a few nuclei. The extent of chromatin unpackaging, but not of frequency of nuclei with formation of extended chromatin fibers, in starved mice that were refed was greater than in well-fed controls. Refeeding induced increase in Feulgen-DNA amounts and regain and redistribution of concanavalin A-reactive nuclear glycoproteins. However, the duration of refeeding used was probably insufficient to reestablish the stereo arrangement of the chromatin-nuclear matrix and to restore chromatin fluidity to the level seen in well-fed mice. CONCLUSIONS: The changes in the liver cell nuclei associated with starvation and refeeding of adult mice involved chromatin supraorganization, hepatocyte proliferation (refeeding), and the loss, regain, and redistribution of nuclear proteins, especially nuclear matrix components, related to chromatin organization and extensibility. These changes are suggested as favoring the silencing and reactivation of transcriptional activities, depending on the organism's nutritional state.

Animals↗
PubMed2005

Extracellular matrix of ostrich articular cartilage.

The composition and organization of the extracellular matrix of ostrich articular cartilage was investigated, using samples from the proximal and distal surfaces of the tarsometatarsus. For morphological analysis, sections were stained with toluidine blue and analyzed by polarized light microscopy. For biochemical analysis, extracellular matrix components were extracted with 4 M guanidinium chloride, fractionated on DEAE-Sephacel and analyzed by SDS-PAGE. Glycosaminoglycans were analyzed by electrophoresis in agarose gels. Structural analysis showed that the fibrils were arranged in different directions, especially on the distal surface. The protein and glycosaminoglycan contents of this region were higher than in the other regions. SDS-PAGE showed the presence of proteins with molecular masses ranging from 17 to 121 kDa and polydisperse components of 67, 80-100, and 250-300 kDa in all regions. The analysis of glycosaminoglycans in agarose-propylene diamine gels revealed the presence of only chondroitin-sulfate. The electrophoretic band corresponding to putative decorin was a small proteoglycan containing chondroitin-sufate and not dermatan-sulfate, unlike other cartilages. The higher amounts of proteins and glycosaminoglycans and the multidirectional arrangement of fibrils seen in the distal region may be correlated with the higher compression normally exerted on this region.

Animals↗
PubMed2004

Cell death evaluation in benzo[a]pyrene-transformed human breast epithelial cells after microcell-mediated transfer of chromosomes 11 and 17.

The incidence of apoptosis and nuclear instability, including the incidence of catastrophic death, were investigated in benzo[a]pyrene (BP)-transformed human breast epithelial cells (BP1-E cell line) after microcell-mediated transfer of chromosomes 11 and 17. Since the introduction of normal chromosomes 11 and 17 into tumorigenic human breast BP1-E cells reverts some of these cells' characteristics (especially those affected by microsatellite instabilities and loss of heterozygosity) to those of parental non-transformed MCF-10F cells, it was expected that the cell death rates would also be affected by this treatment. The transfer of the mentioned chromosomes, especially chromosome 17, to tumorigenic BP1-E cells increased the apoptotic ratios and decreased the nuclear instability ratios, thus showing that the microsatellite instability and loss of heterozygosity induced by BP in these chromosomes of MCF-10F cells affect the control of cell death mechanisms.

Apoptosis↗
PubMed2003

DNA content, chromatin texture and nuclear morphology in benzo[a]pyrene-transformed human breast epithelial cells after microcell-mediated transfer of chromosomes 11 and 17.

BACKGROUND: A relation between the changes in DNA content and chromatin supra-organization and the expression of gradual steps of tumorigenesis has been assessed by image analysis in human breast epithelial cells (MCF-10F) treated with benzo[a]pyrene (BP) (cell lines BP1, BP1-E, BP1-Tras, and others). METHODS: Because abnormal chromosomes 11 and 17 have been associated with neoplastic progression in BP-transformed MCF-10F cells, image analysis of Feulgen-stained tumorigenic BP1-E cells with the microcell-mediated chromosome transfer of normal chromosomes 11 and 17 was carried out. RESULTS: A tendency of DNA amount distribution and nuclear size restoration to values typical of non-transformed MCF-10F cells was demonstrated, especially after the transfer of chromosome 17. No reversion in chromatin texture was found after the transfer of chromosome 11 or 17. CONCLUSIONS: Although the presence of a normal chromosome 17 should be considered among the necessary steps for tumorigenic human breast epithelial cells to recover their normality, a more complex genome balance is required for the entire nuclear chromatin of these cells to recover its totally normal supra-organization and expression.

Benzo(a)pyrene↗
PubMed2003

Image analysis of tendon helical superstructure using interference and polarized light microscopy.

Wave-like structures (WLS also known as crimp) have generally been reported to be planar structures. However, there is evidence that a helical superstructure, rather than a planar one, should be considered. Conditions dictated by supramolecular chemistry, molecular recognition and self-assembly favor the idea of a helical arrangement for collagen bundles in a supramolecular structure. The aim of this work is to provide additional data in support of a helical superstructure for collagen bundles in tendons. Cryosections of fixed flexor bovine tendons and sections of resin-embedded peeled rat tail were studied using polarized light, interference, and phase contrast microscopy. Image analysis was used to find appropriate mathematical descriptors for WLS. Interference colors due to the dispersion of birefringence allowed the detection of a gradual, intertwined twisted fiber organization in WLS, as the angle of the tendon axis was rotated relative to the polarizers. Helical movements of the images of the WLS bands were produced using animation methods. Interference microscopy revealed interference colors associated with different orientations and dry mass concentrations in the fibers, especially in tendon cross-sections, which also exhibited Maltese-cross birefringence images. Similar images were detected by interference microscopy, suggesting a spiral organization of fibers in the section plane. The helical orientation of the fibers was detected by focusing through different planes of sections. Based on a comparison of this superstructure with mesophases, the twisted grain boundary concept is considered to be the most appropriate for the classification of tendon WLS.

Animals↗
PubMedDate not supplied

Collagen birefringence in skin repair in response to red polarized-laser therapy.

We use the optical path difference (OPD) technique to quantify the organization of collagen fibers during skin repair of full-thickness burns following low-intensity polarized laser therapy with two different polarization incidence vectors. Three burns are cryogenerated on the back of rats. Lesion L(parallel) is irradiated using the electric field vector of the polarized laser radiation aligned in parallel with the rat's occipital-caudal direction. Lesion L(perpendicular) is irradiated using the electric field vector of the polarized laser radiation aligned perpendicularly to the aforementioned orientation. Lesion C is untreated. A healthy area labeled H is also evaluated. The tissue samples are collected and processed for polarized light microscopy. The overall finding is that the OPD for collagen fibers depends on the electric field vector of the incident polarized laser radiation. No significant differences in OPDs are observed between L(parallel) and H in the center, sides, and edges of the lesion. Lesions irradiated using the electric field vector of the polarized laser radiation aligned in parallel with the rat's occipital-caudal direction show higher birefringence, indicating that collagen bundles in these lesions are more organized.

Birefringence↗