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Biomedical subjects

A Serrano

Publications and source records attributed to A Serrano.

At least 55 records · Page 3Linked to original sources
PubMed2001

Soluble receptors released during acute pancreatitis interfere with the detection of tumor necrosis factor-alpha.

OBJECTIVE: To evaluate the interfering effect of tumor necrosis factor-alpha soluble receptor when measuring circulating concentrations of tumor necrosis factor-alpha in an experimental model of acute pancreatitis. DESIGN: Randomized, controlled trial. SETTING: Experimental laboratory. SUBJECTS: Male Wistar rats. INTERVENTIONS: Acute pancreatitis was induced by intraductal administration of 5% sodium taurocholate. Saline was administered in a control group. Serums were overloaded with known amounts of tumor necrosis factor-alpha or macrophage inflammatory protein-2. MEASUREMENTS AND MAIN RESULTS: Three hours after induction, serum concentrations of free tumor necrosis factor-alpha, total tumor necrosis factor-alpha, and soluble receptor of tumor necrosis factor-alpha were measured. No detectable concentrations of free tumor necrosis factor-alpha were found in any experimental group. By contrast, significant increases in total tumor necrosis factor-alpha and soluble receptor of tumor necrosis factor-alpha were found after induction of pancreatitis. Overloading of serum with tumor necrosis factor-alpha resulted in detection of 50% of the expected concentrations of free tumor necrosis factor-alpha from control animals and only of 5% from the pancreatitis group. Overloading the serum with macrophage inflammatory protein-2 resulted in a detection of 100% of the expected concentrations in both control and treated animals. CONCLUSION: Circulating soluble receptor of tumor necrosis factor-alpha could interfere with the detection of tumor necrosis factor-alpha in some pathologies, such as pancreatitis, that are associated with increases in soluble receptor of tumor necrosis factor-alpha.

Acute Disease↗
PubMed2001

Complications of central venous catheterization in critically ill children.

OBJECTIVE: Analysis of central venous catheterization complications in different access sites with the Seldinger technique. Patients and Methods: A prospective study (May 1992 through December 1996) of 308 central venous catheterizations in children of different ages in a pediatric intensive care unit. RESULTS: Access sites were the subclavian vein (76.3%), femoral vein (20.4%), and jugular vein (3.2%). The frequency of catheter placement-related complications was 22%, and the frequency of serious catheter placement-related complications was 2.9% (pneumothorax 1.9%, hemothorax 1%). Catheter placement-related complications were more common in the subclavian than in the femoral vein (chi-square, p =.02) for the larger bore catheters (chi-square, p =.01) and for the higher number of attempts (Student's t -test, p <.001). Catheter placement-related complications were not related to the age, weight, or whether the procedure was performed by the staff physician or resident. The overall complication rate for maintenance-related complications was 36%. Maintenance-related complications were more common in younger children (Student's t -test, p =.03). The most frequent maintenance-related complications were mechanical complications (catheter obstruction and central venous thrombosis), and these were higher for femoral access (chi-square, p <.01) and for catheters indwelling for a longer period of time. Infection was found in 5.8% of patients, mainly due to Staphylococcus epidermidis. Infection was not related to the site of venous access or to the length of time the catheter was left indwelling. CONCLUSIONS: Central venous catheterization can be performed readily in children of all ages with an acceptable degree of risk. The immediate complications were more frequent and severe for subclavian vein catheterization, and the highest risk factor was the number of attempts at catheter insertion. Although the most frequent late complications were mechanical, which were higher for the femoral access and long-indwelling catheters, femoral catheters can be left indwelling for longer periods if routine ultrasound follow-up is performed. Infectious complications were independent of the venous access site or the duration of catheterization.

Journal Article↗
PubMed2001

Attenuation by oral N-acetylcysteine of bleomycin-induced lung injury in rats.

Antioxidant therapy may be useful in diseases with impaired oxidant-antioxidant balance such as pulmonary fibrosis. This study examines the effect of N-acetylcysteine (NAC) on bleomycin-induced lung fibrosis in rats. NAC (3 mmol x kg(-1); oral) was given daily from 1 week prior to a single intratracheal instillation of bleomycin (2.5 U x kg(-1)) or saline, until 14 days postinstillation. NAC partially decreased the augmented collagen deposition in bleomycin-exposed rats (hydroxyproline content was 4,354+/-386 and 3,416+/-326 microg x lung(-1) in vehicle-treated and NAC-treated rats, respectively; p < 0.05). The histological assessment using a semiquantitative score showed less collagen deposition and inflammatory cells in NAC-treated rats compared to those receiving bleomycin alone. NAC failed to inhibit the bleomycin-induced increases in lung wet weight and in cell counts and protein levels of bronchoalveolar lavage fluid, but significantly increased total glutathione and taurine levels in bronchoalveolar lavage fluid. These results indicate that oral N-acetylcysteine improves the pulmonary antioxidant protection and may be useful in reducing lung damage produced by bleomycin.

Acetylcysteine↗
PubMed2001

Androgen receptor expression in sertoli cells as a function of seminiferous tubule maturation in the human cryptorchid testis.

Androgen receptor (AR) immunohistochemistry was performed in an archival collection of adult human cryptorchid testes to determine whether AR cellular distribution and intensity of immunostaining were functions of the severity of cellular dysgenesis. The seminiferous tubule histology of cryptorchid testes collected from adults is marked by three specific patterns. 1) Seminiferous tubules are characterized as maintaining focal areas of germinal cell differentiation (albeit incomplete) that are interspersed with 2) tubules composed of Sertoli cells only, these latter cells being principally of the adult type, although dysgenetic and immature Sertoli cells may also be detected. 3) In contrast, there is a class of tubule that is characterized as being composed exclusively of Sertoli cells that are extremely dysgenetic in appearance. The majority of adult-type Sertoli cells found in the first types of tubules exhibited either robust or moderate AR staining intensity. Peritubular cells of these tubules also expressed a similar AR staining intensity. In contrast, in the more dysgenetic and immature type Sertoli cells found in the second type of tubules, the intensity of AR staining was significantly less, if not missing altogether. Finally, in the most dysgenetic tubules, Sertoli cell AR staining was never detected. To our knowledge, this is the first report in the literature that addresses the intensity of AR immunostaining in Sertoli cells of cryptorchid testes. The results presented herein are consistent with the interpretation that the intensity of AR staining in Sertoli cells diminishes as a function of the severity to which the cells are afflicted within a cryptorchid testis and that focal absence of AR expression in Sertoli cells correlates with a lack of local spermatogenesis in the tubules.

Adolescent↗
PubMed2001

Paucicellular variant of anaplastic thyroid carcinoma: report of two cases.

The paucicellular variant of anaplastic carcinoma is an infrequent type of thyroid tumor. It was described as a tumor characterized by very low cellularity and prominent fibrosis, probably secondary to extensive infarction. These features could lead to an erroneous diagnosis of Riedel's thyroiditis. In this paper, we report the clinical and pathological features of two new cases of this unusual entity. Tumor cells were negative for thyroglobulin immunostaining and positive for keratins and p53. Although the number of reported cases is small, the cumulative data on these two cases and the previously reported ones lead us to suggest that the paucicellular variant may occur in younger patients than the conventional anaplastic thyroid carcinoma and that the tumor may be associated with a less aggressive tendency to local progression and metastasis.

Aged↗
PubMed2001

The integration of individual therapy and family therapy in the treatment of child and adolescent psychiatric disorders.

Children influence families and families influence children. Individuals create a family, and a family is more than a sum of its individuals. These dialectic views are at the heart of the clinical application of the integration of individual and family therapy. Any attempt to treat the mental disorders of children and adolescents must consider both views and their treatment implications. The use of combined therapeutic modalities can offer more flexibility, specificity, and precision for the treatment process.

Adolescent↗
PubMed2001

[Colonic aganglionosis with ileal involvement. Ileocolic plasty].

During 1994 through 1999, we have treated five patients (3 boys, 2 girls) with total colonic aganglionosis (TCA) and ileal involvement. In three of them we performed a diverting ileostomy in the neonatal period and at the age of four and five months respectively in the remaining two patients, due to intestinal obstruction. In these two last patients a diagnosis of Hirschsprung's disease was made by anorectal manometry and rectal biopsies in the neonatal period. During laparotomy, a cutaneous ileostomy was created in all patients at the distal end of normal ileum, which was 30 to 110 cm (mean = 71 +/- 37 cm) from the ileocecal valve. After operation, a short bowel syndrome developed in three patients causing fluid and nutritional problems that required prolonged total parenteral nutrition (TPN). The definitive operative repair is performed at 4.5 to 14 months (mean = 8 +/- 3.7 months) by a 12 to 20 cm side-to-side ileocolostomy created between the ileum and aganglionic ascending color (Boley procedure) and ileorectal primary anastomosis (Rehbein procedure) using a circular stapler. Rectal dilatation, irrigation of the colon with saline, loperamide hydrochloride and resincholestyramine were begun in all patients postoperatively. Oral antibiotic prophylaxis, was given to the three patients who suffered from SBS. Oral feedings with semielemental diet were tolerated once stools were semiformed and TPN was discontinued at 8 to 34 days (mean = 21 +/- 1.7 days). postoperatively. After the definitive operation, enterocolitis developed in two patients, requiring one of them a short hospitalization during the episode. A possible explanation for the low incidence of enterocolitis in this series is the systematic postoperative use of irrigations of the colon with saline in all patients. These five patients have been followed-up for growth, development, bowel habit and continence. Follow-up has ranged from 15 to 62 months (mean = 32.2 +/- 19.2 months). Presently, all patients in this series have full enteral feeding and one to three bowel movements per day, with formed or semiformed stools. No patients is incontinent of stool. The patient's body weights (74 to 93%) and heights (89 to 92%) for their age were below average (four patients) or within normal range (one patient). Hemoglobin levels are within normal range in all patients. One patient has iron deficiency and another one has serum ferritin concentration below normal. Three patients have folic acid deficiency. Vitamin B12 absorption is normal in all patients. Although we can not conclude this is a better procedure than others, with is use we have obtained satisfactory results, with an excellent survival, scanty morbidity, a rapid return of bowel function and continence, and an acceptable physical development. During long-term follow-up, patients mus be evaluated for iron and folic acid deficiency.

Child↗
PubMed2000

Mechanistic aspects of the induction of apoptosis by lauryl gallate in the murine B-cell lymphoma line Wehi 231.

The effect of lauryl gallate (antioxidant E-312) has been studied on the mouse B-cell lymphoma line Wehi 231. This compound is able to inhibit protein tyrosine kinases (PTKs) in whole cells and in crude extracts with a better efficiency than other well-known PTK inhibitors such as herbimycin or genistein. Initial events triggered upon the incubation of cells with lauryl gallate in phosphate-buffered saline (up to 1 h) include the inhibition of tyrosine phosphorylation, discharge of the mitochondrial transmembrane potential, and induction of mRNA for Bcl-2. Long-term cultures in complete medium supplemented with fetal calf serum (up to 24 h) in the presence of this compound exhibit clear apoptotic features such as increase in phosphatidylserine in the cell surface, decrease in the functionality of mitochondria, cytochrome c release to the cytosol, activation of caspases, hypodiploidy, and oligonucleosomal breakdown of DNA. Comparison between Wehi cells overexpressing Bcl-2 (Wehi-bcl-2) with Wehi-neo cells shows a delay in the manifestations of the apoptotic signs, indicating that Bcl-2 has a partial protective effect on the apoptosis induced by lauryl gallate. The proapoptotic effect of lauryl gallate is not dependent on DNA or protein synthesis, is not blocked by the chelation of calcium, and is not reverted by N-acetylcysteine.

Acetylcysteine↗
PubMed2000

Role of the PI3K regulatory subunit in the control of actin organization and cell migration.

Cell migration represents an important cellular response that utilizes cytoskeletal reorganization as its driving force. Here, we describe a new signaling cascade linking PDGF receptor stimulation to actin rearrangements and cell migration. We demonstrate that PDGF activates Cdc42 and its downstream effector N-WASP to mediate filopodia formation, actin stress fiber disassembly, and a reduction in focal adhesion complexes. Induction of the Cdc42 pathway is independent of phosphoinositide 3-kinase (PI3K) enzymatic activity, but it is dependent on the p85alpha regulatory subunit of PI3K. Finally, data are provided showing that activation of this pathway is required for PDGF-induced cell migration on collagen. These observations show the essential role of the PI3K regulatory subunit p85alpha in controlling PDGF receptor-induced cytoskeletal changes and cell migration, illustrating a novel signaling pathway that links receptor stimulation at the cell membrane with actin dynamics.

3T3 Cells↗
PubMed2000

[Clinical manifestations of heterozygote familial hypercholesterolemia in Spain. Study of 301 cases from the central and northern areas].

RATIONALE: To characterize clinical manifestations of familial hypercholesterolemia (FH) in Spain. PATIENTS AND METHODS: A group of 301 cases of FH from central and north regions of Spain. RESULTS: With a mean (SD) cholesterol level of 346 (58) mg/dl, only 7.6% of the patients have xanthomas and 20% ischaemic heart disease. 51% have a familial history of ischaemic heart disease. CONCLUSIONS: Different from the results of literature, xanthomas are very infrequent in FH in Spain, so diagnosis should be suspected from other data. The high prevalence of familial history of ischaemic heart disease supports the usefulness of this feature as a marker for diagnosis and prevention.

Adult↗
PubMed2000

Value of sonography in the assessment of space-occupying lesions of the anterior nasal fossa.

PURPOSE: This study was conducted to define the gray-scale, color, and power Doppler sonographic appearances and spectral analysis patterns of anterior nasal masses. METHODS: Eight patients with anteriorly located nasal masses were referred to our hospital for CT of the paranasal sinuses. Subsequently, they were examined with a high-frequency linear-array ultrasound transducer. We performed gray-scale sonography and color and power Doppler imaging. RESULTS: Five masses were nasal hemangiomas. The three remaining masses were a submucosal glandular cyst, a nasolabial cyst, and tuberculum septi hypertrophy. Three of the hemangiomas were histopathologically confirmed. Sonography identified the anatomic origin of all 8 lesions. On color and power Doppler imaging, the 5 hemangiomas exhibited intense vascularity that decreased with compression. Spectral analysis demonstrated arterial and venous flow within the hemangiomas, with resistance indices of 0.60-0.66 and peak systolic velocities of 6.4-18.4 cm/second. The other 3 lesions were avascular or had vascularity only at the periphery. CONCLUSIONS: Anterior nasal fossa tumors can frequently be diagnosed by clinical examination, but specific sonographic and Doppler patterns can help to establish the anatomic origin, the local extension, and the correct diagnosis in indeterminate cases, obviating other diagnostic imaging or surgical procedures.

Adult↗
PubMed2000

beta-amyloid peptides are cytotoxic to astrocytes in culture: a role for oxidative stress.

beta-Amyloid is cytotoxic to neurons in culture by increasing hydrogen peroxide and altering calcium homeostasis. We have evaluated the cytotoxicty of beta-amyloid peptides (betaA(25-35) and betaA(1-40)) and generation of hydrogen peroxide on cortical cultured astrocytes. Twenty-four hours after a single addition of either betaA(25-35) or betaA(1-40) there was a concentration-dependent decrease in viability. This toxicity never exceeded 50% of the population independently of exposure time and concentrations. The subpopulation of astrocytes resistant to betaA(25-35) effects were also insensitive to peroxide. Catalase or vitamin E showed no protective effect against betaA(25-35) toxicity. Dithiothreitol (DTT), N-acetylcysteine (NAC), and cyclosporine A significantly prevented the toxic effects of both betaA(25-35) and peroxide. Inhibition of peroxide detoxifying enzymes increased betaA(25-35) and peroxide toxicity. Exposure to betaA(25-35) or betaA(1-40) increased peroxide production at 2 and 24 h, which was prevented by DTT and NAC, but not vitamin E. Despite the inability of added catalase to reduce betaA toxicity, these results suggest that betaA-induced cytotoxicity to astrocytes in culture is, as in neurons, mediated by generation of hydrogen peroxide.

Alzheimer Disease↗
PubMed2000

Microsatellite instability analysis in tumors with different mechanisms for total loss of HLA expression.

Down-regulation of the expression of major histocompatibility complex molecules is a frequent event that is associated with the poor immunogenicity of tumor cells. Acquired resistance to T-cell-based immunotherapy has been associated with loss of functional beta2-microglobulin expression. This anomaly appears to be particularly relevant in tumors exhibiting a defect in DNA-mismatch repair, and induces structural abnormalities in HLA cell-surface expression that are not reversible by cytokine treatment. We examined HLA expression in 118 melanoma, colon or larynx tumors to identify total loss of HLA class I expression with or without somatic beta2-microglobulin gene mutation. Microsatellite instability was investigated in these tumors to determine whether a replication error phenotype (RER+) implied a particular alteration in HLA phenotype. A total of 7.6% of the tumors showed the RER+ phenotype, and 12.7% were HLA-ABC-negative. In the RER+ group, only one tumor was HLA-ABC-negative and no beta2-microglobulin mutation was identified. In contrast, in the HLA-ABC-negative group, only one tumor showed microsatellite instability. None of the three melanomas that contained beta2-microglobulin mutation exhibited the mutator phenotype. These findings suggest that beta2-microglobulin mutation in human melanoma tumors may arise through a mechanism that does not necessarily involve microsatellite instability. Our results also indicate that somatic mutations of the beta2-microglobulin gene are not the main mechanism of total loss of HLA expression.

Adenocarcinoma↗
PubMed2000

Epoxy-acetogenins and other polyketide epoxy derivatives as inhibitors of the mitochondrial respiratory chain complex I.

Annonaceous acetogenins (ACG), an extensive group of cytotoxic natural products, are antitumor agents whose main mode of action is inhibition of the mammalian mitochondrial complex I. Herein we describe the importance of the different chemical groups along the alkyl chain for optimal inhibitory potency, discussing the structurally relevant factors present in these compounds. For this purpose, a series of epoxide derivatives from alpha-linolenic acid were prepared and their activity compared with that of epoxy-acetogenins and tetrahydrofuranic (THF) acetogenins isolated from Rollinia membranacea.

Electron Transport↗
PubMed2000

[Chemotherapy in germinal and epithelial ovarian cancer].

Generically, ovarian cancer represents a group of tumors with diverse biological and clinical behavior. Thus, germinal cells ovarian tumors, in the vast majority of patients are successfully treated utilizing traditional based on cisplatin chemotherapy. Epithelial ovarian cancer, that accounts for 90% of these cases, although sensitive to chemotherapy has not shown satisfactory results. In the search better tumoral response in the treatment of epithelial ovarian cancer new drugs have surged that promise good results, including docetaxel, topotecan and gemcitabine, both as single agents, or in combination with other therapies utilizing monoclonal antibodies.

Carcinoma↗
PubMed2000

Cytochrome c6 from Cyanophora paradoxa. Characterization of the protein and the cDNA of the precursor and import into isolated cyanelles.

In the eukaryotic alga Cyanophora paradoxa, which does not contain plastocyanin, photosynthetic electron transport from the cytochrome b6/f complex to photosystem I is mediated by cytochrome c6. Cytochrome c6 was purified to homogeneity by column chromatography and FPLC. The relative molecular mass of the holoprotein was determined by two different mass spectrometric methods (californium-252 plasma desorption and UV matrix-assisted laser desorption ionization) giving 9251 +/- 3.3 Da. N-terminal Edman microsequencing yielded information on approx. 30 amino acid residues. Based on these data and on highly conserved regions of cytochromes c6, degenerate oligonucleotides were designed and used for PCR to amplify the genomic DNA of C. paradoxa. Screening of a C. paradoxa cDNA library yielded several clones coding for preapo-cytochrome c6. The deduced sequence of the mature protein was verified by plasma desorption mass spectrometric peptide mapping and shows high similarity to those of cytochromes c6 from cyanobacteria and algae. Cytochrome c6 appears to be encoded by a single nuclear gene (petJ) in C. paradoxa. As the mature protein is located in the lumen of the thylakoid membrane, it has to traverse three biological membranes as well as the unique peptidoglycan layer of the cyanelles before it reaches its final subcellular locale. Thus the transit sequence is composed of two different targeting signals: a stroma targeting peptide resembling those of higher plants with respect to hydropathy plots and amino acid composition and a hydrophobic signal peptide functioning as a thylakoid-traversing domain. There are indications for alternative sorting of part of the cyanelle cytochrome c6 pool to the periplasmic space. This is the first known bipartite transit sequence of a cyanelle precursor protein from C. paradoxa, a model organism concerning the endosymbiotic origin of plastids. Labeled precursor is efficiently imported into isolated cyanelles, then routed into thylakoids and processed to the mature protein. Hitherto, in vitro protein translocation was not reported for cyanobacterial-type thylakoids.

Amino Acid Sequence↗