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Biomedical subjects

C Zaragoza

Publications and source records attributed to C Zaragoza.

At least 19 recordsLinked to original sources
PubMed2004

Native and oxidized low density lipoproteins oppositely modulate the effects of insulin-like growth factor I on VSMC.

OBJECTIVE: Changes in the local expression and signaling activity of the insulin-like growth factor-I (IGF-I) axis regulate growth and survival of plaque-derived vascular smooth muscle cells (VSMC) and influence plaque fate. Recent evidence suggests that accumulation of low density lipoproteins (LDL) in VSMC during the progression of atherogenesis is linked to local changes in IGF-I signaling. We investigated the effects of LDL on the biological actions and downstream signaling pathways mediated by this growth factor in A10 VSMC. METHODS AND RESULTS: We first characterized the effects of LDL on the proliferative and anti-apoptotic actions of IGF-I in A10 VSMC. Native LDL were mitogenic and synergistically enhanced DNA synthesis induced by IGF-I from 4-, 9- up to 7.8-fold, while having no effect on its anti-apoptotic actions. In contrast, oxidized LDL, at oxidation levels that did not modify these actions by themselves, significantly reduced the mitogenic and survival effects of IGF-I by 40% and 60%, respectively. These observations correlated with opposite changes exerted by native and oxidized LDL on the insulin receptor substrate-1 (IRS)-associated PI3 kinase/Akt response to IGF-I. The extracellular signal-regulated kinase (ERK) signaling response was not affected. CONCLUSIONS: Our study demonstrates a previously unidentified modulation of the actions of IGF-I on A10 VSMC by LDL, dependent on their extent of oxidative modification. Our findings suggest that the differential modulation of the PI3 kinase/Akt response to IGF-I play a pivotal role.

Animals↗
PubMed2004

Canine pyometra: a study of the urinary proteins by SDS-PAGE and Western blot.

Canine pyometra often causes glomerulonephritis by immune complex deposition in the glomeruli. Proteinuria, ranging from moderate to severe, may be present secondary to renal damage. To determine urinary protein excretion due to pyometra, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was conducted on urine from 15 bitches with pyometra and 10 healthy bitches. To characterize urinary immunoglobin excretion, Western blot analysis of the urine samples using antibodies to canine IgG and IgA was also performed. Nine bands were detected by electrophoresis in bitches with pyometra, while only four were detected in the healthy animals. The urinary proteins from bitches with pyometra were primarily of glomerular origin; 58% were of medium-high molecular weight (MW), and the remainder were low MW. None of the healthy dogs had IgG or IgA in their urine, whereas three bitches with pyometra had IgG in their urine and another bitch with pyometra had both IgG and IgA. The low proportion of bitches with urinary immunoglobins was probably be due to early diagnosis of the disease. Although only a limited number of dogs was used, this study is apparently the first to characterize the electrophoretic pattern of urinary proteins and to quantify urinary excretion of IgG and IgA in bitches with pyometra.

Animals↗
PubMed2003

Cardiovascular morbidity and obesity in adult liver transplant recipients.

There is a direct relationship between the grade of obesity and mortality based on the increased cardiovascular diseases, cancer, etc. However, the results of studies in renal and liver allograft recipients relating obesity to morbidity and mortality are contradictory. A retrospective cohort study of 170 patients transplanted between March 1987 and July 1997 showed obesity to be identified in 77 (45.3%) patients. During the mean follow-up of 5 years posttransplantation, 16 (9.4%) patients experienced cardiovascular complications, including 10 patients with ischemic cardiac syndromes (five acute infarctions and five angina), five patients with acute cerebrovascular accidents, and one patient with intermittent lower limbs claudication. The prevalence of obesity at 1, 3, 5, 7, and 9 years after transplantation was 58.2%, 56.9%, 60.3%, 59.5%, and 66.4%, respectively. Compared with the baseline value, the BMI was increased at 1 year posttransplantation (25.78), a significant difference. No significant differences were found between the mean BMI values of patients with and without cardiovascular diseases, or overweight and morbidly obese patients compared to the normal weight population. Among liver transplant recipients, obesity was a frequent complication after transplantation, but it was not clearly associated with increased morbidity and mortality secondary to cardiovascular disease.

Adult↗
PubMed2003

Biotypes resistant to herbicides in paddy fields in the Iberian Peninsula.

A consequence of modern agriculture and its dependence on herbicides, is the appearance of resistant weed populations. The first case of resistance on the Iberian Peninsula was found in Portugal and it was in a population of Alisma plantago-aquatica, resistant to bensulfuronmethyl, an ALS-inhibitor. For the same herbicide, control problems with Cyperus difformis were found in some Spanish rice fields. In the same rice field area, tolerance was observed in some Echinochloa spp. when auxinic herbicides (quinclorac) were used and some resistant Echinochloa spp. populations were found due to the long use of PS II inhibitors herbicides (propanil). The association of active ingredients, rotation of crops and adoption of mechanical control methods are the main strategies to combat resistance to herbicides.

Acetolactate Synthase↗
PubMed2002

Hydrogen peroxide regulation of bovine endothelin-converting enzyme-1.

Vascular injury leads to the production of reactive oxygen species (ROS), but the mechanisms by which ROS contribute to vascular pathology are not completely understood. We hypothesized that ROS increase endothelin converting enzyme (ECE-1) expression. We found that glucose oxidase (GO) increases ECE-1 mRNA, protein, and activity in bovine aortic endothelial cells. Catalase abolishes this effect. Glucose oxidase treatment of endothelial cells transactivates the ECE-1 promoter. The ECE-1 promoter element that mediates this response to GO is located between -444 and -216 bp. This region contains a STAT response element, and GO activates STAT-3 binding to this STAT response element. Our data suggest that STAT3 mediates hydrogen peroxide induction of ECE-1 expression.

Animals↗
PubMed2000

Superoxide regulation of endothelin-converting enzyme.

Reactive oxygen species (ROS) act as signaling molecules in the cardiovascular system, regulating cellular proliferation and migration. However, an excess of ROS can damage cells and alter endothelial cell function. We hypothesized that endogenous mechanisms protect the vasculature from excess levels of ROS. We now show that superoxide can inhibit endothelin-converting enzyme activity (ECE) and decrease endothelin-1 synthesis. Superoxide inhibits ECE but hydrogen peroxide and nitric oxide do not. Superoxide inhibits ECE by ejecting zinc from the enzyme, and the addition of exogenous zinc restores enzymatic activity. Superoxide may inhibit other zinc metalloproteinases by a similar mechanism and may thus play an important role in regulating the biology of blood vessels.

Animals↗
PubMed1999

Inducible nitric oxide synthase protection against coxsackievirus pancreatitis.

Coxsackievirus infection causes myocarditis and pancreatitis in humans. In certain strains of mice, Coxsackievirus causes a severe pancreatitis. We explored the role of NO in the host immune response to viral pancreatitis. Coxsackievirus replicates to higher titers in mice lacking NO synthase 2 (NOS2) than in wild-type mice, with particularly high viral titers and viral RNA levels in the pancreas. Mice lacking NOS have a severe, necrotizing pancreatitis, with elevated pancreatic enzymes in the blood and necrotic acinar cells. Lack of NOS2 leads to a rapid increase in the mortality of infected mice. Thus, NOS2 is a critical component in the immune response to Coxsackievirus infection.

Acute Disease↗
PubMed1999

Interaction of interferon regulatory factor-1 and nuclear factor kappaB during activation of inducible nitric oxide synthase transcription.

We investigated the molecular mechanism for the synergistic induction of inducible nitric oxide synthase transcription by TNF-alpha and IFN-gamma. Since TNF-alpha and IFN-gamma stimulate cells in part by activating NF-kappaB and IRF-1, we hypothesized that these two transcription factors interact with each other. IRF-1 and NF-kappaB co-localize in the nucleus of stimulated macrophages. Co-immunoprecipitation experiments show that IRF-1 and NF-kappaB interact in stimulated but not resting cells. Super-shift experiments show that IRF-1 and NF-kappaB interact while binding to their respective DNA binding sites. These results demonstrate the existence of a physical interaction between IRF-1 and NF-kappaB proteins in vivo. We next suggested that this interaction between IRF-1 and NF-kappaB bends the DNA of the iNOS promoter region. Using a cyclization assay, we demonstrate that nuclear extracts from stimulated cells accelerate the rate of conversion of a linear to circular DNA, compared to extracts from resting cells. However, stimulated nuclear extracts cannot affect the rate of cyclization of a promoter with a mutant IRE or kappaB site. Furthermore, stimulated nuclear extracts depleted of IRF-1 and NF-kappaB cannot induce cyclization. We conclude that IRF-1 and NF-kappaB interact in vivo, and that this interaction physically bends the indicible nitric oxide synthase promoter DNA. This interaction may explain the mechanism by which IFN-gamma synergistically augments inducible nitric oxide synthase transcription.

Animals↗
PubMed1999

An antiviral mechanism of nitric oxide: inhibition of a viral protease.

Although nitric oxide (NO) kills or inhibits the replication of a variety of intracellular pathogens, the antimicrobial mechanisms of NO are unknown. Here, we identify a viral protease as a target of NO. The life cycle of many viruses depends upon viral proteases that cleave viral polyproteins into individual polypeptides. NO inactivates the Coxsackievirus protease 3C, an enzyme necessary for the replication of Coxsackievirus. NO S-nitrosylates the cysteine residue in the active site of protease 3C, inhibiting protease activity and interrupting the viral life cycle. Substituting a serine residue for the active site cysteine renders protease 3C resistant to NO inhibition. Since cysteine proteases are critical for virulence or replication of many viruses, bacteria, and parasites, S-nitrosylation of pathogen cysteine proteases may be a general mechanism of antimicrobial host defenses.

3C Viral Proteases↗
PubMed1998

Impaired liver regeneration in inducible nitric oxide synthasedeficient mice.

The mechanisms that permit adult tissues to regenerate when injured are not well understood. Initiation of liver regeneration requires the injury-related cytokines, tumor necrosis factor (TNF) alpha and interleukin (IL) 6, and involves the activation of cytokine-regulated transcription factors such as NF-kappabeta and STAT3. During regeneration, TNFalpha and IL-6 promote hepatocyte viability, as well as proliferation, because interventions that inhibit either cytokine not only block hepatocyte DNA synthesis, but also increase liver cell death. These observations suggest that the cytokines induce hepatoprotective factors in the regenerating liver. Given evidence that nitric oxide can prevent TNF-mediated activation of the pro-apoptotic protease caspase 3 and protect hepatocytes from cytokine-mediated death, cytokine-inducible nitric oxide synthase (iNOS) may be an important hepatoprotective factor in the regenerating liver. In support of this hypothesis we report that the hepatocyte proliferative response to partial liver resection is severely inhibited in transgenic mice with targeted disruption of the iNOS gene. Instead, partial hepatectomy is followed by increased caspase 3 activity, hepatocyte death, and liver failure, despite preserved induction of TNFalpha, IL-6, NF-kappabeta, and STAT3. These results suggest that during successful tissue regeneration, injury-related cytokines induce factors, such as iNOS and its product, NO, that protect surviving cells from cytokine-mediated death.

Animals↗
PubMed1998

The role of inducible nitric oxide synthase in the host response to Coxsackievirus myocarditis.

The host response to Coxsackievirus infection is complex, including T lymphocytes, B lymphocytes, natural killer cells, and macrophages. Although Coxsackievirus infection induces expression of inducible nitric oxide synthase (NOS2; EC 1.14.13.39) in macrophages, the precise role of NOS2 in the host response to Coxsackievirus myocarditis has been unclear. We show, by using mice homozygous for a disrupted NOS2 allele, that Coxsackievirus replicates to higher titers in NOS2(-/-) mice, that the host lacking NOS2 clears virus more slowly than the wild-type host, and that myocarditis is much more severe in infected NOS2(-/-) mice. These data show that NOS2 is crucial for the host response to Coxsackievirus in the mouse.

Animals↗
PubMed1998

Involvement of transcriptional mechanisms in the inhibition of NOS2 expression by dexamethasone in rat mesangial cells.

In previous studies we reported that stimulation of rat mesangial cells (RMC) with lipopolysaccharide (LPS) + tumor necrosis factor alpha (TNF-alpha) (L/T) elicits inducible nitric oxide synthase (NOS2) mRNA expression, which is inhibited by dexamethasone (DX). We have now analyzed the mechanisms responsible for this inhibitory effect. Dexamethasone had no destabilizing effect on NOS2 mRNA. Transfection of RMC with several luciferase reporter constructs from the 5' flanking regulatory region of the rat NOS2 gene established the importance of the NF-kappa B site in the transcriptional activation of the NOS2 gene. DNA mobility shift assays showed activation by L/T of the NF-kappa B complex in a time-dependent manner. Dexamethasone specifically inhibited this activation in a process dependent on the glucocorticoid receptor and with a markedly greater effect when it was added prior to L/T. Dexamethasone increased the expression of the I kappa B-alpha transcript and protein in the cytoplasm. While treatment of RMC with L/T induced the transient decrement of cytoplasmic p65 levels and its appearance in the nucleus, preincubation with DX prevented this effect. Co-immunoprecipitation and immunocytochemical studies demonstrated that I kappa B-alpha is associated with p65 in the cytoplasm of RMC after treatment with DX and L/T. These results prove that inhibition of NF-kappa B-mediated transcription is a crucial mechanism by which DX inhibits NOS2 expression, and that this occurs by increasing cytoplasmic I kappa B-alpha levels and sequestering the activating subunits of NF-kappa B in the cytoplasm. The need for previous induction of I kappa B-alpha could provide a molecular explanation for the limited efficacy of these agents in the therapy of septic shock.

Animals↗
PubMed1997

Nitric oxide inhibition of coxsackievirus replication in vitro.

Nitric oxide is a radical molecule with antibacterial, -parasitic, and -viral properties. We investigated the mechanism of NO inhibition of Coxsackievirus B3 (CVB3) replication in vitro by determining the effect of NO upon a single replicative cycle of CVB3 grown in HeLa cells. Transfection of inducible NO synthase cDNA into HeLa cells reduces the number of viral particles produced during a single cycle of growth. Similarly, a noncytotoxic concentration of the NO donor S-nitroso-amino-penicillamine reduces the number of viral particles in a dose-dependent manner. To explore the mechanisms by which NO exerts its antiviral effect, we assayed the attachment, replication, and translation steps of the CVB3 life cycle. NO does not affect the attachment of CVB3 to HeLa cells. However, NO inhibits CVB3 RNA synthesis, as shown by a [3H]uridine incorporation assay, reverse transcription-PCR, and Northern analysis. In addition, NO inhibits CVB3 protein synthesis, as shown by [35S]methionine protein labeling and Western blot analysis of infected cells. Thus, NO inhibits CVB3 replication in part by inhibiting viral RNA synthesis by an unknown mechanism.

Cell Survival↗
PubMed1994

[The femoral vein route: an exceptional alternative for the implantation of permanent pacemakers].

A case of thrombosis in the superior vena cava after two permanent pacemaker implantations is described. Ten years ago the patient had a permanent pacemaker implanted because of disturbances in his cardiac rhythm. Five months later he was readmitted with pacemaker malfunction due to failure of the electrode and a new lead was introduced. In 1989 the generator presented "end of life" and the depleted battery was changed. In February, 1993 he presented a new pacemaker malfunction and thrombosis in the superior vena cava. We suggest that in similar cases the iliac vein approach should be performed and short-term anticoagulant therapy should be considered.

Arrhythmias, Cardiac↗
PubMed1993

Rapid identification of Triticeae genotypes from single seeds using the polymerase chain reaction.

An easy and quick protocol has been developed for DNA analysis via PCR. Single cereal endosperm or small leaf pieces can be separately processed in several PCR reactions. The resultant PCR patterns are equivalent to those obtained with standard DNA extraction protocols using either specific or random primers. Intra- and inter-specific variability can be detected. This method allows the analysis of a large number of individuals in early stages prior to the plant sowing.

DNA↗
PubMed1991

[A prospective and comparative study of 262 laparoscopic cholecystectomies].

A prospective, comparative study is made of 262 patients (195 males, 67 females) subjected to laparoscopic cholecystectomy. Two groups were considered: simple cholelithiasis (SC) (187 cases), and complicated cholelithiasis (CC) (75 cases: 63 acute cholecystitis, 8 hydrocholecystitis, 4 pancreatitis). Mean age was 51 among the SC cases, and 57 in the CC patients. Mean operating time was 67 and 96 minutes for the SC and groups, respectively. Preoperative complications were more frequent in the CC group (51.4%) than in the SC patients (24%)--immediate laparotomies being performed in 2 and 25% of the SC and CC patients, respectively. Mortality was zero, with similar morbidity in both groups. Mean hospitalization time was 4.9 and 3.4 days for the CC and SC groups, respectively.

Age Factors↗
PubMed1989

[Hernial strangulation of Meckel's diverticulum: Littre's hernia. Apropos of 4 cases].

Hernial strangulation of Meckel's diverticulum (Littre's hernia) is a rare anatomoclinical form. It represents 10% of all complications of Meckel's diverticulum (8.8% of our cases), and complications like hemorrhage, perforation and diverticulitis are fairly frequent. Four cases of Littre's hernia are presented: two males and two females, with an average age of 67 years (range 50-83 years), representing 0.08% of all the inguinal-crural hernias operated in the department. The clinical manifestations were those of intestinal obstruction because a mixed type Littre's hernia was involved, with compromise of the diverticulum and its intestinal loop. Preoperative diagnosis is unlikely in strangulation without disturbances in the intestinal transit and, in fact, is even less likely if it is accompanied by obstruction. The diagnosis is thus almost always intraoperative. The correct treatment is surgery after restoring the patient's hemodynamic equilibrium. Simple and/or loop diverticulectomy via herniotomy, herniolaparotomy or laparotomy are debated. We think that this disorder can generally be resolved using the inguinal approach, as in any strangled hernia, with the technical option of using a larger, more comfortable and safer approach in cases of important obesity and/or deterioration of the loop (necrosis, perforation). In elderly patients with uncomplicated Littre's hernia and Meckel's diverticulum, abstention from diverticular exeresis may be justifiable. Of the four patients, the first two died from cardiogenic shock and pulmonary embolism, respectively; the last two evolved well (except for a wound abscess).

Aged↗