PubMed Health⌕ Search

Biomedical subjects

C Corrales

Publications and source records attributed to C Corrales.

13 recordsLinked to original sources
PubMed2005

Muscle-derived stem cells in tissue engineering: defining cell properties suitable for construct design.

The terms construct or tissue equivalent refer to neotissue produced by tissue engineering techniques. The elements forming the construct are scaffolds on which cells are "recreated" to form an engineered-tissue sensitive to certain cell signals. The ability of the cells to expand and differentiate on the scaffold is determined by properties such as fixation, adhesion, proliferation and migration. Among the cell types that seem to be most promising for designing constructs are tissue-residing, or adult, stem cells, which show two main features: a capacity to differentiate into many cell lineages and the power of self-renewal. These features make them good candidates for cell replacement therapies. Here, we report the identification, isolation and culture of muscle stem cells aimed at establishing the ideal culture in terms of defining when the cultured cell population would show optimal characteristics for transfer to the scaffold to obtain a particular construct. Stem cells harvested from the dorsal muscle of white New Zealand rabbits were cultured in vitro and characterized 5 to 14 days after the start of culture. Fibroblasts obtained from the same experimental animal served as controls. The stem cells were examined by light and scanning electron microscopy. For stem cell identification, we used the antibodies anti-m-cadherin, anti-CD34 and anti-Myf-5. The markers of muscle differentiation used were: anti-vimentin, anti-alpha-actin, anti-desmin and anti-myosin. The expression profiles of the different markers of muscle differentiation and TGFbeta1 in the cell cultures were confirmed by Western blotting. Proliferation rates were determined by monitoring tritiated thymidine incorporation. The thymidine incorporation rate was substantially higher for the population of undifferentiated cells than for control fibroblasts obtained from the same animal. During the first five days of culture, most cells were negative for all the markers examined, with the exception of m-cadherin, CD34 and Myf-5, although discrete signs of vimentin expression started to emerge. After 14 days of culture, the adult stem cells showed vimentin (94.2%) and desmin (33.8%) expression yet scarce labeling for myosin (16.2%) and alpha-actin (8.3%). Control fibroblasts showed intense labeling for vimentin (99.3%) and alpha-actin (62.2%), while less than 2% of the population expressed myosin (0.9%) and desmin (1.6%). After two weeks of culture, muscle-derived stem cells show good proliferative and adhesion properties as they initiate differentiation. These conditions seem ideal for obtaining the desired construct.

Actins↗
PubMed2004

Long-term behaviour of cryopreserved arterial grafts versus prosthetic micrografts.

INTRODUCTION: When a patient has no suitable vessels for use as grafts in bypass or reconstruction procedures, two of the options available are the use of a cryopreserved vessel or an expanded polytetrafluoroethylene (ePTFE) prosthesis. This study was designed to compare the long-term behaviour of these vascular substitutes. MATERIAL AND METHODS: We established three study groups by grafting the following vessel substitutes to the iliac artery in Spraque-Dawley rats: arterial autografts (GI, n=12), cryopreserved syngenic arterial grafts (cryoisografts) (GII, n=12), and ePTFE micrografts (GIII, n=12). The animals were sacrificed 180 days after surgery, at which time the graft specimens were morphologically evaluated by light and electron microscopy, immunolabelling (ED1/alpha-actin) and morphometric analysis of the neointima. RESULTS: At the time of sacrifice, graft patency was 100% for the autografts and cryoisografts, while 10% of the ePTFE micrografts showed fully-occlusive thrombosis. Intimal hyperplasia was observed in grafts in GI and GII; the neointima being thinner in the cryoisografts (54.36 +/- 2.26 microm) than the autografts (161.30 +/- 3.91 microm). The endothelium formed over the prosthetic micrografts was unstable, with areas of subendothelial thickening (9.37 +/- 3.18 microm). Cell loss and medial layer degeneration were observed in both GI and GII specimens, while the GIII grafts were colonised by cells on their luminal surface. CONCLUSIONS: All three grafts show good long-term tolerance when used in an arterial setting. Following long-term implant, autografts and cryoisografts show similar alterations that give rise to the complete loss of the muscle component of the tunica media along with the formation of a stable neointima. This new layer takes on the role of the tunica media.

Animals↗
PubMed2003

In vitro mesothelialization of prosthetic materials designed for the repair of abdominal wall defects.

The aim of this study was to evaluate the in vitro response of mesothelial cells (MC) in terms of their ability to cover different biomaterials. MC were harvested from human omentum. The MC from the first passage were seeded onto different biomaterials from 10 min to 24 h: PL-PU99 (polypropylene-polyurethane); DM (ePTFE); PL (polypropylene); and PL + Col (polypropylene-collagen). The prosthetic surface covered was examined by microscopy and quantified. PL-PU99: The MC were adhered to the biomaterial 10 min post-incubation. At 4 h, the 53.12+/-7.86% of the prosthesis were coated with polygonal cells. At 12 h, 96.32+/-11.32% of the biomaterial was coated. DM: between 30 min to 8 h, the MC cells form small, round colonies. At 12 h, polygonal and fusiform secretory cells were observed (68.94+/-5.78%). 93.54+/-11.49% of surface was coated after 24 h. PL: only isolated cells were observed on the prosthesis. PL + Col: MC form a monolayer over prosthetic surface after 18 h (90.21+/-9.76). We conclude: (a) MC formed a stable monolayer over all the biomaterials tested with the exception of the PL due to its porosity. (b) The PL-PU99 showed the greatest potential for in vitro mesothelialization compared to the PL-Col and DM prostheses.

Journal Article↗
PubMed2002

The use of ischaemic vessels as prostheses or tissue engineering scaffolds after cryopreservation.

OBJECTIVE: to evaluate the condition of organ donor arteries subjected to prolonged cold-ischaemia followed by cryopreservation, for their possible use as vascular grafts. MATERIALS AND METHODS: fresh specimens of human iliac artery from organ donors were used as controls. These arteries were divided into two portions, one of which was cryopreserved in an automated freezer. A further group of arteries was immersed in Wisconsin solution and kept for 4 days at 4 degrees C (cold-ischaemia). After this period, the arteries were also cut into two, and one of these portions was cryopreserved. All the cryopreserved arterial segments were stored for a month and then subjected to automated gradual thawing. The thawed specimens were evaluated by light microscopy, scanning and transmission electron microscopy, immunohistochemical analysis (MMPs, elastin, CD31, von Willebrand factor) and the in situ detection of fragmented DNA (TUNEL method). RESULTS: the most marked changes induced by cryopreservation were partial vessel deendothelialisation and morphological changes in cells of the intima that were in the process of detachment. No significant changes were observed in the medial layer, other than discrete elastic fibre fragmentation. Following cold-ischaemia, the endothelium was the most affected layer, with large denuded areas and exposure of the fibroelastic layer. Increased MMP-2 expression was also noted after cold-ischaemia. When subjected to both cold-ischaemia and cryopreservation, a large proportion of endothelial cells showed positivity for the TUNEL technique, however, no significant difference was observed between the ischaemic and the ischaemic/cryopreserved specimens. CONCLUSIONS: prolonged cold-ischaemia causes some additional damage to the arterial wall compared to cryopreservation alone. However, the structural component of the ischaemic vessel remains in a condition that is suitable for subsequent cryopreservation and use as a vessel substitute or a scaffold for tissue engineering.

Adult↗
PubMed2002

Inflammatory cells induce neointimal growth in a rat arterial autograft model.

Subendothelial invasion by leukocytes is a sign of intimal thickening in arteriosclerosis and in the response of a vessel to mechanical damage. Our study was designed to establish whether these cells are implicated in the formation of a neointima in an autologous arterial graft model in the rat and to evaluate the effects of cyclosporin A (CsA). Three study groups were established according to whether the animals were treated with CsA-Cp (Sandimmun), CsA-Et (ethanol vehicle) or received no treatment (control group). Both drug forms were administered (5 mg/kg/day, s.c.) from 4 days prior to surgery until the time of sacrifice. Antibodies specific for lymphocytes (CD4, CD8), monocytes/macrophages-ED1, smooth muscle alpha-actin and the von Willebrand factor (vWF) were used to identify the cells in the grafted arterial wall. In control grafts, the neointima had formed by 2 weeks post-implant. However, the cells comprising this layer generally presented no positivity whatsoever towards the antibodies employed. At 50 days, the new layer was observed to be formed by a vWF-positive endothelium and alpha-actin-positive cells. In all three groups, several polymorphonuclear (PMN) cells adhered to the denuded luminal surface from 7 days onwards. In the treated animals, neutrophils and monocytes were seen to infiltrate intimal and medial layers during the later post-implant stages. Around the third week post-implant, the neointima had reached the grafted segment from the distal portion of the recipient artery, and by 50 days it was similar to that seen in control specimens. Our findings suggest that: a) neutrophils play a role in neointimal thickening in this arterial autograft model; and b) CsA promotes the adhesion and infiltration of neutrophils in the injured arterial wall.

Animals↗
PubMed2001

Gradual thawing improves the preservation of cryopreserved arteries.

This study was designed to test a slow, controlled, automated process for the thawing of cryopreserved arteries, whereby specimen warming is synchronized with the warming of its environment. Segments of minipig iliac artery, 4-5 cm in length, were subjected to controlled, automated cryopreservation in a biological freezer at a cooling rate of 1 degrees C/min to -120 degrees C, followed by storage in liquid nitrogen at -196 degrees C for 30 days. Following storage, the arterial segments were subjected to rapid (warming rate of approximately 100 degrees C/min) or gradual (1 degrees C/min) thawing. Thawed specimens were processed for light microscopy and for scanning and transmission electron microscopy, Cell death was determined by the TUNEL method. Metalloproteinase (MMP) expression was estimated by immunohistochemical analysis. Most of the cryopreserved vessels subjected to rapid thawing showed spontaneous fractures, mainly microfractures, whereas these were absent in slowly thawed specimens. In rapidly thawed vessels, the proportion of damaged cells was double that observed in those thawed more gradually. Increased intensity and extent of MMP-2 expression was shown by rapidly thawed specimens. The slow-thawing protocol tested avoids the formation of spontaneous fractures and microfractures and the accumulation of fluid within the arterial wall tissue. This results in improved tissue preservation.

Animals↗
PubMed2001

Potential role of a new anti-beta3 integrin antibody in the development of intimal hyperplasia after vascular surgery: an in vitro smooth muscle cell model.

The occurrence of intimal hyperplasia after vascular surgery is an ongoing concern in current clinical practice. Among the many factors involved in the development of this pathology, platelet adhesion and myointimal proliferation play a major role. Both these processes are mediated by integrins (mainly alphavbeta3 integrins). Over the past years, several substances have been designed to delay or inhibit the cell proliferation that leads to hyperplasia and mainly include monoclonal antibodies directed against integrins. The aim of the present study was to evaluate the effects of an antibody denoted P37 (anti beta3 integrin) on human smooth muscle cells (SMC) and its role in blocking the B3 subunit. To this end, SMC from human umbilical artery were cultured in the presence or absence of the cell substrate vitronectin (VN) and incubated with P37. After 4 days of treatment, determination was made of cell proliferation and migration. Smooth muscle cells grown on VN showed increased proliferation and migration compared to control VN-free cultures. However, the presence of P37 in the culture medium inhibited proliferation and reduced migration. Combined treatment with VN and P37 led to improved proliferation but VN was unable to reverse the effects on migration observed in the former cultures. Results suggest that in vitro, P37 is capable of blocking human SMC beta3 integrins and thus impedes cell proliferation and migration These findings may have clinical implications related to modulation of the development of hyperplasia.

Antibodies↗
PubMed2001

Chromosome polysomy and histological characteristics in oral premalignant lesions.

Head and neck tumorigenesis has been postulated to represent a multistep process driven by the accumulation of carcinogen-induced genetic changes throughout the exposed tissue field. To better explore this genetic instability process at the tissue level, 59 regions within 26 biopsy tissue specimens from individuals with oral leukoplakia have been subjected to chromosome 9 in situ hybridization analysis, and the degree of chromosome instability was related to known clinical/pathological parameters associated with tumor risk. Whereas chromosome indices were similar between high-risk lesion sites and low-risk lesion sites, high-risk lesions showed higher levels of chromosome polysomy than did low-risk sites [median PIs (polysomy indices), 2.1 versus 1.4, respectively]. Similarly, dysplastic regions showed significantly higher chromosome polysomy levels than hyperplastic regions (median PIs, 2.4 versus 1.5, respectively). Interestingly, however, hyperplastic regions in the same biopsy as dysplastic regions showed two-times higher polysomy levels than those in biopsies without dysplasia (median PIs, 2.6 versus 1.3, respectively), suggesting that chromosome polysomy determinations provide a field measurement for the degree of ongoing genetic insult. Finally, chromosome polysomy tended to persist or increase in the superficial epithelial layers in regions showing koilocytosis, whereas their frequency decreased in nonkoilocytotic regions, suggesting that epigenetic factors may serve to perpetuate the levels of genetically unstable cells in the epithelium. These results provide direct support for the field cancerization process and suggest that measurements of genetic instability might provide additional biological information beyond histology and lesion site characteristics in the assessment of head and neck cancer risk.

Adult↗
PubMed1999

Alcohol and stroke: a community case-control study in Asturias, Spain.

The relationship between alcohol consumption and stroke is uncertain. Heavy alcohol consumption has been associated with an increased risk of stroke, while light drinking appears to be protective. However, the evidence is not uniform. We sought to examine the relationship between alcohol consumption and stroke, according to stroke type. We performed a population-based case-control study from September 1990 to December 1991. The study comprised 467 incident cases of stroke and 477 controls aged between 40 and 85. Case was defined following WHO criteria and control was randomly selected from the study base population. Alcohol exposure was obtained by medical interview. We found that consumption of less than 30 g/day of alcohol was protective against all stroke types combined, the multivariated adjusted odds ratio (OR) was 0.58 (95% confidence interval [CI], 0.41-0.83). Moderate alcohol drinking is also protective against all cerebral infarction combined (OR = 0.53; 95% CI, 0.35-0.80) and cortical infarction (OR = 0.40; 95% CI, 0.18-0.86). Drinking up to 30 g/day of alcohol has a borderline protective effect on deep cerebral infarction (OR = 0.40; 95% CI, 0.16-1.02) and has no effect on intracerebral hemorrhage (OR = 0.88; 95% CI, 0.44-1.74). Heavy alcohol drinking, over 140 g/day, is a risk factor for all stroke types combined (OR = 3.2; 95% CI, 1.1-9.7), all cerebral infarction combined (OR = 5.0; 95% CI, 1.5-16.3), small deep cerebral infarction (OR = 9.7; 95% CI, 2.6-36.7), intracerebral hemorrhage (OR = 6.2; 95% CI, 1.3-24.0), and is marginally associated with superficial cerebral infarction (OR = 4.6; 95% CI, 1.0-20.6). The relationship between alcohol and stroke depends on the alcohol dose and the pathology of the disease. Atherosclerosis of the large and medium cerebral arteries is found mainly in superficial cerebral infarction, and this type of stroke shows a J-shaped relationship with alcohol similar to that found in coronary heart disease, suggesting that they are similar diseases. On the other hand, arteriosclerosis of the penetrating arteries has been found in deep cerebral infarction and intracerebral hemorrhage, while atherosclerosis is not prominent. This may explain why alcohol does not have a protective effect on cerebral hemorrhage whereas heavy drinking is a strong risk factor in these two types of stroke.

Adult↗
PubMed1999

Family history and stroke: a community case-control study in Asturias, Spain.

BACKGROUND: Family history of stroke has been considered as a risk factor for stroke, but this relationship is controversial. Some, but not all, studies have found an independent association between family history of stroke and stroke. This study examines the relationship between family history of stroke and all stroke types combined, cerebral infarction and intraparenchymatous haemorrhage. METHODS: This is an incidence type, population-based case-control study. Cases were defined following WHO criteria and controls were randomly selected from the study-base population. Family history of stroke was obtained by medical interview. A total of 470 cases and 477 controls, aged 40-85 years, form the subjects of the study. RESULTS: Family history of stroke in a first-degree relative is an independent risk factor for all stroke types combined, multivariate adjusted odds ratio (OR) 1.74, 95% confidence interval (CI) 1.24-2.44, for cerebral infarction, OR = 1.79 (95% CI 1.25-2.56), but not for intraparenchymatous haemorrhage, OR = 1.71 (95% CI 0.91-3.17). Risk of all stroke types combined was independently associated with a positive history of father with stroke OR = 1.93 (1.19-3.54) with a positive history of sibling with stroke, OR = 1.67 (95% CI 1.03-2.71) and a borderline significant association with a positive history of mother with stroke OR = 1.45 (95% CI 0.92-2.29). Cerebral infarction was independently associated with a positive history of father with stroke OR = 2.05 (95% CI 1.17-3.59), a positive history of sibling, OR = 1.69 (95% CI 1.01-2.84) and a borderline significant association with a positive history of mother with stroke OR = 1.58 (95% CI 0.97-2.56). Intracerebral haemorrhage was not significantly associated with a positive history of father with stroke OR = 1.39 (0.55-3.58) with a positive history of sibling, OR = 1.83 (95% CI 0.77-4.40), or with a positive history of mother with stroke OR = 1.36 (95% CI 0.59-3.09). CONCLUSIONS: Family history of stroke is found in this study to be an independent risk factor for all stroke types combined and for cerebral infarction. Genetic factors may be involved, but it cannot be ruled out that the observed relationship is confounded by other risk factors, especially family aggregation of life-styles.

Adult↗
PubMed1996

[Stroke incidence in Asturias, 1990-1991].

BACKGROUND: Stroke, with a rate of 121/100,000 was the second cause of death in Asturias, Spain. Here we communicate the results of a population based stroke register in the oriental health districts of Asturias. METHOD: The study took place between October 1, 1990 and May 30, 1991, covering a population of 652,549. Surveillance was both active and passive and included the public and private hospitals, and the primary health care. Death certificates could not be checked due to legal reasons. We defined case following the WHO criteria. RESULTS: During the eight months of study 708 case occurred. The crude incidence rate of first stroke was 132.4/100,000 and that of any stroke, 162.7/100,000. The age adjusted incidence to the world population was, respectively, 61.3/100,000 and 73.6/100,000. There were no differences in the incidence across sexes. Age showed a strong effect in cerebral infarctation and less marked in intracerebral hemorrhage Infarcts are very rare in women before 50. Distribution of stroke type was: infarct: 77%; intracerebral hemorrhages: 14%: subarachnoid hemorrhage: 4% and unspecified stroke: 4%. Almost 50% of the strokes occurred in the morning hours, from 6:00 am to 12:00 am also during the cold season, winter and fall, the proportion of stroke was higher than during the warm season. CONCLUSION: Stroke is an important cause of morbi-mortality in Asturias. The magnitude of mortality is larger than the expected from the incidence. It maybe explained by a high case/fatality ratio in Asturias due to proportion of hemorrhagic stroke, the ageing of the population and the distribution of competing causes of death. However, we cannot rule out a small incomplete registration of cases, mostly in patients over 85. We estimated the incidence of any stroke, given underegistration, to be 176/100,000 for any stroke.

Adult↗
PubMed1984

[Effect of formaldehyde on the protection of proteins in the silage of the peanut plant (Arachis hypogaea)].

An experiment was performed to study the formaldehyde protective effect on the ensilaged whole peanut plant protein (21.5% CP). The experimental design consisted in four treatments 5, 10, 15 and 20% formaldehyde, which was added in the proportion of 5 lt, per ton. A control group without any formaldehyde was also included. There were no significant differences in regard to pH among treatments (5.56 to 5.70). Ammonia concentration dropped significantly in all treatments, a finding which suggests a protective effect on protein nitrogen degradation to non-protein nitrogen (NH3). A lactic acid fermentation was observed, without any difference between treatment and the control group. Nevertheless, there was a reduction in propionic acid and ethanol concentration in all the silages. Therefore, it is concluded that there was an inhibition of the fermentation process in all the silages treated, and that the addition of formaldehyde at the 5% level is a satisfactory way of protecting this type of feed.

Ammonia↗