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J Mora-Galindo

Publications and source records attributed to J Mora-Galindo.

At least 19 recordsLinked to original sources
PubMed2005

Ultrastructural analysis of guided nerve regeneration using progesterone- and pregnenolone-loaded chitosan prostheses.

Recently, numerous guide chambers for the treatment of injured nerves made up of different biomaterials have been designed, capable of hosting living cells or carrying neurotrophic or neuroactive substances to be directly released to the injured tissue. In this study, chitosan prostheses containing neurosteroids (progesterone and pregnenolone) were used for bridging a 10-mm gap in the rabbit facial nerve. Gas chromatography was used to quantify neurosteroid content in the prostheses prior to and after subcutaneous implantation at different periods of up to 60 days. The regeneration of the nerve fibers were evaluated at 15 and 45 days after axotomy by means of ultrastructural morphometric analysis. Different nerve fibers regenerative patterns were seen depending the groups studied and the analyzed stages. At 15 days after axotomy, the newly regenerating tissue revealed Schwann cells holding nonmyelinated nerve fiber bundles in an incipient and organized regenerative pattern. At 45 days, the regenerating tissue showed myelinated nerve fibers of different sizes, shapes, and myelin sheath thickness. Although the regeneration of the nerve fibers under neurosteroid treatment showed statistically significant differences in comparison with vehicle regenerated tissue, progesterone-loaded chitosan prostheses produced the best guided nerve regeneration response. These findings indicate that chitosan prostheses allowed regeneration of nerve fibers in their lumen, and when containing neurosteroids produced a faster guided nerve regeneration acting as a long-lasting release delivery vehicle.

Animals↗
PubMed2003

Facial nerve regeneration through progesterone-loaded chitosan prosthesis. A preliminary report.

Biodegradable nerve guides have represented new treatment alternatives for nerve repairing. They are gradually biodegradable, exert biological effects directly to the injured nerve, and act as drug- or cell-delivery devices. Furthermore, progesterone (PROG) has been demonstrated to promote injured peripheral nerve regeneration. In this study, it was hypothesized that PROG delivered from chitosan prostheses provides better facial nerve regenerative response than chitosan prostheses with no PROG. As there are no reports on the use of the former as nerve-guide material in the regeneration of injured nerves, this is the main objective of the present work. Chitosan prostheses containing PROG were used to bridge 10-mm gaps in rabbit facial nerves. The regenerated nerves were evaluated 45 days after implantation in animals with the use of light microscopy and morphometric analysis. Gas chromatography was used in order to quantify PROG content in prosthesis prior to and after implantation in subcutaneous tissue at different periods of up to 60 days. In addition, the prosthesis walls were evaluated with histological techniques in order to assess their integrity and the surrounding tissue reaction. Chitosan prostheses allowed PROG release during the time needed for nerve regeneration. At 45 days myelinated nerve fibers were observed in both the proximal and distal stumps. This parameter and the N ratio were higher in the progesterone-treated group when compared to that of the vehicle control. Findings indicate that chitosan prostheses were useful in nerve regeneration, acting as a long-lasting PROG delivery device a faster nerve regeneration.

Animals↗
PubMed2001

Electrophysiological and morphological alterations in peripheral nerves by the pig paramyxovirus of blue eye disease in neonatal pigs.

The pig paramyxovirus of blue eye disease (PPBED) produces central nervous system (CNS) damage leading to death in piglets. However, when PPBED was injected into the muscle and came into contact with hind limb peripheral nerves and was transported to the CNS, it did not cause death and could be a mechanism by which to induce protection. This study analyses whether PPBED causes electrophysiological and morphological alterations in infected hind limb peripheral nerves. It also studies, whether PPBED induces the onset of haemagglutination inhibitory antibodies (HIA) when it is transported to the spinal cord after medial gastrocnemius (MG) intramuscular injection. PPBED was detected by an immunohistochemical method and nerve morphology was studied using electron microscopy. The physiological status of the nerve was evaluated with electrophysiological techniques. The electrical threshold of the infected MG nerve increased four- or five fold compared to that in the ipsilateral lateral gastrocnemius or in the MG nerve on the control side. The infected nerve fibres underwent myelin sheet disarrangement and their internal fibre diameter decreased. PPBED induced the onset of HIA.

Animals↗
PubMed1996

Pathogenic action of Entamoeba invadens: intestinal epithelium invasion by trophozoites in vitro.

Interactions between live Entamoeba invadens trophozoites and guinea-pig caecal explants were studied. A high percentage of amoebae adhering to the apical surface of epithelial cells was observed 10-20 min after infection, but no histopathological changes were observed. After 30 min, mild oedema at the base of the interglandular epithelium and death of some epithelial cells were evident. The epithelial barrier was invaded by amoebae at desquamating zones and phagocytosis of epithelial cells or cellular debris was occasionally observed. Invasion of the mucosa and tissue necrosis became more severe with increased time of incubation. The continuity of epithelial lining was severely compromised after 2 h of infection and erosive lesions were prominent in the mucosa. These results demonstrate that E. invadens is able to invade the intestinal epithelium although it reportedly lacks the powerful cytotoxic and cytolytic elements described for E. histolytica.

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PubMed1995

Simultaneous growth and mass encystation of Entamoeba invadens under axenic conditions.

Encystation of Entamoeba invadens IP-1 strain trophozoites was induced in low glucose medium (LG). The numbers of trophozoites, cysts and nuclei per cyst were determined; excystation of detergent-resistant axenic cysts was induced in both BI-S-33 and LG media. It was found that after 48 and 72 h of incubation in LG, cyst production was higher than trophozoites inoculated, 90 and 65% of those cysts being morphologically viable, respectively, as differentiation proceeded cysts became tri- and tetranucleated.E. invadens cysts were able to excyst either in BI-S-33 or LG media. There were no differences in growth kinetics when amebic cultures from cysts excysted in BI-S-33 were compared with parent strain. On the contrary, lower yields of trophozoites were achieved with amebas excysted and further cultured in LG medium, but they were able to grow and simultaneously undergo mass encystation. This, as well as other evidence, suggests that E. invadens trophozoites are able to modulate their physiology according to the nutrients and other factors available in the medium, in order to accomplish, growth, encystation or simultaneous growth and mass encystation. Induction of life cycle of pathogenic amebas under axenic conditions can provide answers to inhibit encystment and/or excystment.

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PubMed1993

Intracellular digestion of human erythrocytes by Entamoeba histolytica: a kinetic study in vitro.

The objective of this investigation was to quantitatively evaluate, by using light and transmission electron microscopy, the intracellular digestion of human erythrocytes (HE), ingested by Entamoeba histolytica trophozoites in vitro. Amebas fed 10 min with HE were postincubated 3-12 h at 36.5 degrees C without HE, and fixed with glutaraldehyde. After staining by the benzidine reaction, HE per ameba, and percent of amebas containing at least one HE were determined by light microscopy. Trophozoites ingested an average of eight HE per ameba and 92% of them contained HE after the 10 min pulse. Erythrocytes were clearly observed as reddish-brown corpuscles in the amebic cytoplasm. During postphagocytosis incubations progressive loss of HE staining, as well as changes in size of food vacuoles, were observed, thus proving the intracellular digestion of HE. The hydrolysis of HE was corroborated with the electron microscope, the HE cytoplasmic matrix being the first structure catabolized and later the plasma membrane. Quantitative analysis demonstrated decrease of 56% of ameba containing HE, and 1.35 HE per ameba on average, after 3 h postphagocytosis. Afterwards, both parameters decreased at a slow rate until HE disappeared. The t1/2 of HE within amebas was 2 h.

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PubMed1990

Quantitative evaluation of intracellular degradation in Entamoeba invadens.

A quantitative study on digestion of erythrocytes by Entamoeba invadens was attempted. Trophozoites of the IP-1 strain were fed red blood cells for 30 min, and subsequently phagocytosis was stopped by means of osmotic shock; post-phagocytosis incubations for up to 15 h were made in order to evaluate intracellular digestion, after staining the red blood cells with benzidine. Eighty-two per cent of trophozoites were capable of phagocytosing erythrocytes, containing an average of 5.5 erythrocytes per amoeba. Erythrocyte digestion within amoebae was shown by loss of benzidine-stainable material and proceeded with a first-order kinetics, with a t1/2 approximately 7 h. Within 15 h there were no amoebae containing erythrocytes. The procedure described may be useful for the evaluation of intracellular digestion in other Entamoeba species.

Animals↗
PubMed1988

Size-uniform heparin fragments as nuclear decondensation and acrosome reaction inducers in human spermatozoa.

Using size- uniform mixtures of di-, tetra-, octa- and decasaccharides obtained from the depolymerization of heparin with heparinase, we have studied the activity that these low molecular weight heparin fragments may have on the acrosome reaction and sperm nuclei decondensation processess. Swelling of human spermatozoa nuclei was stimulated by heparin and their fragments and was dependent on the incubation time and directly correlated with the size of the fragment tested. Disaccharides were unable to increase the number of swollen nuclei. At short times (2-8 hrs) decasaccharides were the most active substances tested, including heparin. Only heparin and the tetra- and decasaccharides showed a significant increase in the number of acrosome-reacted spermatozoa, both fragments were more active than heparin at 2 hour incubation. Hexa- and octasaccharides induced a slight increase in the number of acrosome reacted spermatozoa and disaccharides were ineffective. The presence in animal systems of oligosaccharides derived from macromolecules and having specific biochemical properties, remembers the recent discovery of to those mediated by oligosaccharins in plants may exist in animals.

Acrosome↗
PubMed1987

Prokaryotic-eukaryotic cell junctions between spiral-shaped bacteria and cecal epithelium of the guinea pig.

Scanning electron microscopy demonstrated that the cecum of the guinea-pig is colonized by numerous spiral-shaped bacteria; these microorganisms, which adhere to mucosa at one end, were found exclusively on the brush border of the surface epithelium. The membranes of sectioned bacteria have a set of electron-dense bands girdling the tip adhered to epithelium. Freeze-fracture replicas of the bacteria revealed the prokaryote-eukaryote junction as a set of ridges on the P-face of outer membrane; the numerous particles of E-face were arranged in parallel rows; on the other hand, the apical plasma membrane and subjacent cytoplasm of epithelium occupied by the spiral-shaped bacteria did not show a structural counterpart. Observations suggest that one end of the spiral-shaped bacteria possesses specialized membrane components that permit specific attachment to the apical surface of epithelial cells.

Animals↗
PubMed1986

Maturation of tight junctions in guinea-pig cecal epithelium.

By means of the freeze-fracture technique and in tracer studies it is demonstrated that the structure of tight junctions and the permeability to lanthanum of the guinea-pig cecal epithelium change during maturation of cells. Height and strand number of tight junctions in the apical-basal direction increase as crypt cells migrate to the surface of the epithelium. Likewise, the interlacing of continuous strands was greater in surface than in crypt junctions. The numerous free-ends, isolated individual free-strands and maculae occludentes found in crypt cells were absent in surface epithelial cells. Goblet cells, located at the bottom of crypts, displayed tight junctions similar in characteristics to those of cells located in the middle region of crypts. Cells at the surface and in middle regions of crypts possess tight junctions impermeable to lanthanum, whereas junctions between cells located at the bottom of crypts often were permeable to the tracer, indicating that permeability decreases as the epithelial cells mature. Genesis and maturation mechanisms related to structural configuration of tight junctions are discussed.

Animals↗
PubMed1983

Phenytoin effects on tissues of Mongolian gerbils (Meriones unguiculatus).

1. Phenytoin was intraperitoneally injected in six different experimental groups of adult Mongolian gerbils of both sexes at doses of 5, 100 and 150 mg/kg of body wt during 7 and 14 days. 2. Their brain, cerebellum, liver and kidney DNA, RNA and protein content were measured by conventional procedures. 3. The reference values of these rodents' cellular DNA were calculated through hepatocytes isolated following an intracardiac perfusion with collagenase in Hanks solution. 4. A concentration of 7.2 micrograms of DNA per 10(6) cells was found. 5. Phenytoin did not affect tissues of groups of animals receiving daily doses of 5 mg/kg of weight during 7 and 14 days of treatment; although a slight increase of protein concentration was observed in liver (P less than 0.01) and kidney (P less than 0.05). 6. RNA values were found to be significantly decreased in cerebellum (P less than 0.001), brain (P less than 0.05) and kidney (P less than 0.05) of those animals receiving the drug throughout 14 days. 7. DNA concentration was found to be decreased in all four tissues obtained from animals treated with daily doses of phenytoin of 100 (P less than 0.001) and 150 (P less than 0.001) mg/kg of body wt throughout 14 days. 8. These results indicate that phenytoin affected tissue cellularity only when administered at high doses and 14 days of interval of drug administration (P less than 0.001).

Animals↗
PubMedDate not supplied

Congo red effect on cyst viability and cell wall structure of encysting. Entamoeba invadens.

BACKGROUND: The cell wall of Entamoeba invadens cysts is composed of chitin microfibrils as the main structural component. It has been demonstrated in yeast that the chitin cell wall assembly is altered by dyes such as Congo red (CR) and Calcofluor. METHODS: The purpose of this work was to study the cell wall assembly under the effect of CR dye on encysting E. invadens by means of light and electron microscopy, after the amebas were subjected to the effect of 100-2,000 micrograms CR/mL. Experiments were performed either in BI-S-33 or in mLG media. RESULTS: Trophozoite growth was not inhibited by 100-1,000 micrograms/mL CR after 8 days of incubation in BI-S-33 medium. However, low levels of growth were observed with 2,000 micrograms/mL of dye. No significant differences in morphologically viable (hyaline) cyst production occurred after 24-48 h, when 100 micrograms CR/mL was used, while the highest concentration of CR (2,000 micrograms/mL) resulted in a significant decrease of hyaline cyst yield; dead cysts prevailed in cultures, particularly at 72 h of CR treatment. Differentiation of amebas incubated in the presence of 500-2,000 micrograms/mL CR produced abnormal chitin deposits, rendering irregularly thick or double cell walls, as shown by transmission and scanning electron microscopy. Cyst cultures obtained under 100 micrograms/mL CR produced as many trophozoites as did the control when they were incubated in BI-S-33, but only low numbers of trophozoites were found in culture cysts obtained under higher CR doses. CONCLUSION: Our results suggest that CR affects E. invadens encystment, alters the cell wall formation, and also affects the cyst viability.

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