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Biomedical subjects

J A Rodríguez

Publications and source records attributed to J A Rodríguez.

At least 19 recordsLinked to original sources
PubMed2003

Antioxidant vitamins increase the collagen content and reduce MMP-1 in a porcine model of atherosclerosis: implications for plaque stabilization.

Degradation of extracellular matrix, particularly interstitial collagen, promotes plaque instability and contributes to restenosis after vascular injury. We have explored the effects of vitamins C and E on the collagen content and metalloproteinase-1 (MMP-1) expression after angioplasty in hypercholesterolemic pigs. Iliac angioplasty was performed on 18 minipigs divided into three diet groups: a normal-cholesterol (NC), a high-cholesterol (HC) and a high-cholesterol plus vitamins C+E (HCV). Four weeks later, after sacrifice, the vascular collagen content and MMP-1 protein expression, along with the plasma caseinolytic activity and lipid peroxidation, were measured. MMP-1 was also determined in arterial rings stimulated with native low-density lipoproteins (LDL) isolated from experimental groups. Cholesterol-rich diet augmented plasma lipid peroxidation (P<0.05), reduced the collagen content and increased vascular MMP-1 expression after injury (P<0.05). Enhanced caseinolytic activity (identified as MMP-1) was also observed in HC plasma samples and in supernatants from arterial rings incubated with HC-LDL. Vitamins C and E markedly increased neointimal collagen content (P<0.01), reduced the hypercholesterolemia-induced changes in vascular MMP-1 (P<0.05) and diminished plasma and ex vivo caseinolytic activity. Vitamins C and E may help stabilize atherosclerotic plaque after angioplasty and favor vascular remodeling by increasing collagen content and reducing vascular MMP-1 expression in porcine hypercholesterolemia.

Analysis of Variance↗
PubMed2002

[Non-invasive continuous positive airways pressure for post-extubation laryngitis in pediatric patients].

UNLABELLED: Post-extubation laryngeal edema (PLE) is a common complication (10-15%) in pediatric intensive care units, and some authors have reported high failure rates for conventional treatment. HYPOTHESIS: Non-invasive continuous positive airways pressure (CPAP) in children with PLE may have a lower failure rate than conventional management. PATIENTS AND METHOD: Twenty-five patients were needed to detect a difference between the two treatment groups. The patients were assigned to receive the conventional treatment (nebulized epinephrin and humidified oxygen) or the experimental treatment (non-invasive CPAP treatment for 18 hours), using a randomized block design (10-patient blocks). After 9 months, the study was halted when a significant difference emerged between the two groups. RESULTS: Of 270 children extubated during the study, 28 (10.3%) developed PLE and 25 met the enrollment requirements. Thirteen were assigned to conventional therapy and 12 to CPAP. General characteristics, time of intubation, FiO2 upon admission, use of corticoids before extubation and scores for respiratory difficulty upon admission were similar in the two groups (p > 0.05). With conventional therapy, 5 (38.5%) children improved and 8 patients worsened or remained the same. Eleven (91.7%) of the patients receiving CPAP improved (p = 0.01). Those who failed on conventional treatment were prescribed CPAP and all then improved, although one had to be re-intubated. CONCLUSION: The hypothesis was confirmed. CPAP treatment reduced the failure rate by 53.2% in comparison with conventional therapy.

Age Factors↗
PubMed2001

[A case of Carney syndrome].

The Carney complex is an autosomal dominant syndrome characterised by multiple neoplasies, including myxomas at various sites (cardiac, cutaneous, mammary), spotty pigmentation, endocrine overactivity (Cushing's syndrome, acromegalia), testicular tumours and schwannomas. This report describes the case of a 43-year-old woman with an acute inferior myocardial infarction, probably due to coronary embolization from a large left atrial myxoma and who presented this association. A brief review of the Carney complex is provided after discussion of this rare case that required an screening of family members.

Adult↗
PubMed2001

Hyperhomocysteinemia in liver cirrhosis: mechanisms and role in vascular and hepatic fibrosis.

Numerous clinical and epidemiological studies have identified elevated homocysteine levels in plasma as a risk factor for atherosclerotic vascular disease and thromboembolism. Hyperhomocysteinemia may develop as a consequence of defects in homocysteine-metabolizing genes; nutritional conditions leading to vitamin B(6), B(12), or folate deficiencies; or chronic alcohol consumption. Homocysteine is an intermediate in methionine metabolism, which takes place mainly in the liver. Impaired liver function leads to altered methionine and homocysteine metabolism; however, the molecular basis for such alterations is not completely understood. In addition, the mechanisms behind homocysteine-induced cellular toxicity are not fully defined. In the present work, we have examined the expression of the main enzymes involved in methionine and homocysteine metabolism, along with the plasma levels of methionine and homocysteine, in the liver of 26 cirrhotic patients and 10 control subjects. To gain more insight into the cellular effects of elevated homocysteine levels, we have searched for changes in gene expression induced by this amino acid in cultured human vascular smooth muscle cells. We have observed a marked reduction in the expression of the main genes involved in homocysteine metabolism in liver cirrhosis. In addition, we have identified the tissue inhibitor of metalloproteinases-1 and alpha1(I)procollagen to be upregulated in vascular smooth muscle cells and liver stellate cells exposed to pathological concentrations of homocysteine. Taken together, our observations suggest (1) impaired liver function could be a novel determinant in the development of hyperhomocysteinemia and (2) a role for elevated homocysteine levels in the development of liver fibrosis.

Arteriosclerosis↗
PubMed2001

A new continuous cell line from the mosquito Psorophora confinnis (Diptera: Culicidae) and its susceptibility to infections with some arboviruses.

A new cell line, PC-0199-BR, was established from embryonated eggs of the mosquito Psorophora confinnis. To date (September 2000) it has had 62 continuous passages. This is the first report of a cell line of mosquitoes belonging to the genus Psorophora. Cell growth initially was achieved in the MM/VP12 medium, supplemented with 20% fetal bovine serum; however, the subcultures were later adapted to Grace's medium with 10% fetal bovine serum. Cell morphology in the primary cultures was heterogeneous; but later in the established cell line, the predominant cell type was epithelioid. Cultured cells were predominantly diploid (2n=6); however, chromosome abnormalities were observed in a small proportion of the cells in later passages. C and G band patterns were also determined in the karyotype. The cell line isozyme profiles coincided with pupae and adult samples of the species taken from the same colony. A preliminary arbovirus susceptibility study for the cell line was undertaken. No evidence was observed of contamination of the cell line with bacteria, fungi or mycoplasma.

Animals↗
PubMed2001

[Ultrastructural changes of the retinal pigment epithelium in pigs fed with a fat rich diet].

PURPOSE: To determine if the intake of a rich diet is related to ultraestructural changes and with an increase in lipofuscin accumulation in porcine retinal pigment epithelium (RPE). METHODS: The animals were divided into two groups of 6 pigs each. In the first group (control), a restricted diet of chow mix was supplied. The second group (fat-fed group) was fed with the same type of nutritional diet, however one third of the food was replaced by saturated fatty acid. Total cholesterol, HDL, LDL, and triglycerides were determined at the beginning and at the end of the experiment. After 12 weeks, the eyes were enucleated and the RPE structure was examined by electron microscopy. RESULTS: No significant differences were observed in the RPE lipofuscin accumulation between the control group and the fat-fed group (p=0.3). However, morphological disorders such as nuclear pyknosis, accumulation of electron dense particles in Bruch's membrane, and the accumulation of empty and lipid-like vacuoles in the cytoplasm were observed in the RPE of the fat-fed group but not in the control animals. CONCLUSIONS: The ultrastructural changes observed in the porcine RPE can be related to a high fat diet to the increase in lipid plasma levels.

Animals↗
PubMed2001

[Silent adenoma type 3: the importance of the ultrastructural study in the differential diagnosis of pituitary adenoma associated with hyperprolactinemia in a case].

The association of hyperprolactinemia over 100 ng/ml and a pituitary adenoma is usually diagnostic of prolactinoma. However type 3 pituitary adenomas can occur with similar serum prolactin values. We report a 31 years old woman that consulted due to headache and photopsiae. She had a serum prolactin level of 148 ng/ml and imaging studies showed a solid tumor that occupied the sellar region and most of the left temporal fossa. The tumor was partially resected and the patient recovered her lost visual field. Light microscopy showed an acidophilic and in part chromophobe adenoma. Immuno-histochemistry was positive for prolactin and growth hormone. Electron microscopy disclosed features of a silent type 3 adenoma such as big cells with cytoplasmic prolongations, pleomorphic nuclei and a greatly developed rough endoplasmic reticulum.

Adenoma↗
PubMed2001

Application of an innovative methodology to improve the starting-up of UASB reactors treating domestic sewage.

This study shows the results obtained during the starting-up evaluation of an UASB reactor treating domestic sewage. It is located in the municipality of Ginebra, Valle del Cauca region in Colombia. Its design flow is 7.5 l/s with a maximum capacity of 10 l/s. The reactor was seeded with a deficient quality inoculum which accounted for 20% of the total reactor volume. The starting-up methodology comprised the sequential washing of the sludge (inoculum) by applying three different upflow velocities. This procedure resembles what other authors term the "selective pressure method". Once the sludge was washed, the reactor was started-up with an initial hydraulic retention time (HRT) of 24.9 hours, which was steadily reduced down to 6.7 hours in the final stage. Along the starting-up phase, there was a positive evolution in terms of quantity, quality and spatial distribution of the sludge. Consequently, there was a positive evolution in organic matter removal mechanisms. For HRT above 14 hours, the removal mechanisms were mainly physical whilst for HRT below 9 hours the removal mechanisms were mostly biological. Based on the above considerations and on the water quality parameters measured, it may be concluded that the start-up of an UASB reactor for domestic sewage treatment seeded with a low quality inoculum can be done with HRT as low as 15 or 12 hours. In this way, it is possible to reduce the starting-up period of these reactors down to 4 to 6 weeks, provided that the starting-up methodology is properly applied.

Bacteria, Anaerobic↗
PubMed2000

Identification of a functional nuclear export sequence in BRCA1.

Germ-line mutations in the tumor suppressor gene Brca1 confer increased susceptibility to breast and ovarian cancers. BRCA1 is a 1863-amino acid protein with roles in transcriptional regulation and the cellular responses to DNA damage. Given its function in these nuclear processes, the subcellular localization of BRCA1 is an important issue and has been the object of recent controversy. BRCA1 contains two nuclear localization signals and is most frequently detected in the cell nucleus by immunofluorescence microscopy. In this study, we show that BRCA1 is a nuclear-cytoplasmic shuttling protein, capable of both entering and exiting the nucleus. We identified a functional Rev-type nuclear export sequence ((81)QLVEELLKIICAFQLDTGL) near the amino terminus of BRCA1 that facilitates export via the CRM1/exportin pathway. Mutational inactivation of this nuclear export sequence, or treatment of cells with the CRM1-specific export inhibitor leptomycin B, induced nuclear accumulation of ectopic full-length BRCA1. Moreover, overexpression of the CRM1 export receptor resulted in decreased nuclear localization of endogenous BRCA1. The unexpected ability of BRCA1 to shuttle between nucleus and cytoplasm may have implications for the regulation and function of this tumor suppressor.

3T3 Cells↗
PubMed2000

Gastroprotective effect of essential oil from Croton cajucara Benth. (Euphorbiaceae).

The gastroprotective activity of the essential oil from the bark of Croton cajucara Benth (Euphorbiaceae) was assessed in three different models of experimentally induced gastric ulcer in mice. At oral dose of 100 mg/kg the essential oil reduced gastric lesions induced by hypothermic restraint stress and HCl/ethanol significantly. In the HCl/ethanol model a dose-dependent gastroprotective effect was found. Moreover, significant changes in gastric parameters such as pH, secretion rate and total gastric acid were found after intraduodenal administration of essential oil under ligated pylorus (Shay) conditions. The acute toxicity of essential oil was assessed in mice. The LD50 values were 9.3 and 680 mg/kg for oral and intraperitoneal administrations, respectively. The cytotoxicity of essential oil was studied also. A dose-dependent cell viability inhibition was found in V79 fibroblast cell cultures with an IC50 of 22.9 microg/ml. Our results support the pharmacological study of this essential oil.

Animals↗
PubMed2000

Expression of neuronal nitric oxide synthase in several cell types of the rat gastric epithelium.

The aim of this study was to identify which cell types of the rat gastric epithelium express neuronal nitric oxide synthase (nNOS) because the results of the previous studies have been very divergent regarding this point. By the combination of immunohistochemical (IHC) and in situ hybridization (ISH) techniques, we detected expression of nNOS in chief and mucosecretory cells of the gastric epithelium. Moreover, some gastric endocrine cells were immunoreactive for nNOS, although they could not be distinguished in sections treated with ISH techniques. The strongest signal for all antibodies in IHC techniques was obtained when microwave (MW) heating was performed before the IHC procedure. Our results indicate that in the gastric epithelium a variety of cell types are able to produce NO. The NO produced by the different cell types (chief, mucous, and endocrine) may form a complex network of paracrine communication with an important role in gastric physiology.

Animals↗
PubMed2000

[Syndrome of apparent mineralocorticoid excess caused by a deficiency of 11 beta-hydroxysteroid dehydrogenase: clinical and genetic study in a Chilean family followed for 19 years].

An 11-year old girl was seen in 1981 with hypokalemia, low renin, low aldosterone, and severe hypertension. A medical adrenalectomy with dexamethasone and aminoglutethimide, and the blockade of mineralocorticoid receptors with spironolactone improved her condition, but the blockade of glucocorticoid receptors with RU-486 worsened it. An aldosterone infusion induced no changes. A sister was born in 1982 with similar findings. Both patients had an impaired ability to convert cortisol to cortisone after an oral load of 200 mg cortisol. In urine, an elevated ratio for metabolites of cortisol to metabolites of cortisone was found. These data suggested a defect in the activity of renal 11 beta-hydroxysteroid dehydrogenase. Both parents were asymptomatic, phenotypically normal and non-consanguineous. Their urinary metabolites of cortisol and cortisone were normal before and after stimulation with ACTH. However, the mother reached a peak plasma cortisone concentration 3 SD below the mean reached by normal subjects after an oral 200-mg cortisol load, a fact that suggests that this test could be used to detect heterozygotes. The genetic studies revealed a homozygous mutation on exon 3 of the HSD11K gene, which by substituting TGC for CGC changes Arg 213 for Cys and induces a loss of 84% of the enzymatic activity in transfected cells. Both unrelated parents had the same heterozygous mutation. Both patients have been treated with dexamethasone but have also required spironolactone. The older sister has also required high doses of nifedipine to lower her blood pressure. After 19 years of follow-up, the older sister has become normotensive and normokalemic under therapy, and reached a final height of 140 cm at age 17. The younger sister has increased her mean blood pressure at a rate of 1 mm Hg per year, in spite of treatment. Her final height is 143.5 cm.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗
PubMed2000

[Infective endocarditis: short and long-term results in 261 cases managed by a multidisciplinary approach].

BACKGROUND: Early diagnosis, an effective treatment and prompt recognition of complications are essential to improve the prognosis of infective endocarditis (IE). AIM: To report the results of a multidisciplinary approach to diagnosis and management of patients with IE at the Universidad Católica de Chile Hospital. PATIENTS AND METHODS: The clinical history, diagnosis, treatment and outcome of 261 episodes (Duke criteria) of IE admitted between January 1980 and January 1999 were analyzed. These included 185 episodes of native, 73 of prosthetic valve and 3 of nonvalvular IE. RESULTS: Sixty nine percent of patients were men and the mean age was 49 +/- 16 years. Seventy five percent had a definite diagnosis of IE (Duke). S. viridans, staphylococci and enterococci together constituted 85% of the isolated bacterial strains. Twenty seven had culture-negative IE, related to a high incidence of antibiotic therapy prior to diagnosis. Transesophageal echocardiography was performed in 102 cases and it detected vegetations in 91% of aortic and 96% of mitral IE, rupture or prosthesis dehiscence in 67% of aortic and 52% of mitral IE and abscesses in 51% of aortic and 15% of mitral IE. Fifty one percent developed heart failure and 34% had embolic events. S. aureus IE was associated to a higher incidence of embolic events, complications which contraindicated surgery and increased mortality rate (27%). Of all patients, 40% were treated exclusively with antibiotics, 52% were operated on and 8% had surgical indication but were nonoperable because of serious complications. The overall mortality was 16.3%: 13% in the medical, 9% in the surgical and 81% in the non-operable groups. The type of treatment and mortality rates did not differ between IE of native valves and prosthetic valves. Long term follow up showed survival rates of 73% at 5 years and 66% at 10 years. CONCLUSION: A multidisciplinary approach may be very helpful to improve the prognosis of IE.

Adolescent↗
PubMed1999

Induction of TIMP-1 expression in rat hepatic stellate cells and hepatocytes: a new role for homocysteine in liver fibrosis.

Elevated plasma levels of homocysteine have been shown to interfere with normal cell function in a variety of tissues and organs, such as the vascular wall and the liver. However, the molecular mechanisms behind homocysteine effects are not completely understood. In order to better characterize the cellular effects of homocysteine, we have searched for changes in gene expression induced by this amino acid. Our results show that homocysteine is able to induce the expression and synthesis of the tissue inhibitor of metalloproteinases-1 (TIMP-1) in a variety of cell types ranging from vascular smooth muscle cells to hepatocytes, HepG2 cells and hepatic stellate cells. In this latter cell type, homocysteine also stimulated alpha 1(I) procollagen mRNA expression. TIMP-1 induction by homocysteine appears to be mediated by its thiol group. Additionally, we demonstrate that homocysteine is able to promote activating protein-1 (AP-1) binding activity, which has been shown to be critical for TIMP-1 induction. Our findings suggest that homocysteine may alter extracellular matrix homeostasis on diverse tissular backgrounds besides the vascular wall. The liver could be considered as another target for such action of homocysteine. Consequently, the elevated plasma levels of this amino acid found in different pathological or nutritional circumstances may cooperate with other agents, such as ethanol, in the onset of liver fibrosis.

Animals↗