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Biomedical subjects

S Pascual

Publications and source records attributed to S Pascual.

At least 19 recordsLinked to original sources
PubMed2006

Functional status of beta-2-adrenoceptor in isolated membranes of mature erythrocytes from patients with cirrhosis and oesophageal varices.

Propranolol is a widely used drug for prophylaxis of variceal bleeding in patients with cirrhosis, but not all patients show an adequate clinical response. This variability may be in relation to beta adrenoceptor activity, but no information is available in this setting. Thirty-nine patients with advanced cirrhosis and presence of oesophageal varices were sequentially included. We studied the function of beta-2-adrenoceptor in isolated membranes of mature erythrocytes obtained from patients by measuring cyclic AMP (cAMP) production before and after isoproterenol. Blood samples obtained from 11 healthy volunteers were used as control. Patients showed a six-fold increase in the mean basal cAMP production as compared to healthy volunteers. Isoproterenol produced a small, non-significantly and highly variable increase in the AC activity in patients compared with controls. cAMP values remain stable after three months of continuous treatment with oral beta-blockers in both groups. Patients without antecedent of variceal bleeding or with an active alcohol intake showed a significantly higher isoproterenol effect. In conclusion, beta-receptor function in human erythrocytes membranes is altered in patients with cirrhosis and oesophageal varices.

Adenylyl Cyclases↗
PubMed2006

A comparison of two different dosages of somatostatin combined with sclerotherapy for the treatment of acute esophageal variceal bleeding: a prospective randomized trial.

BACKGROUND: the association of somatostatin (SMT) with endoscopic therapy in patients with cirrhosis and variceal bleeding significantly improves the control of the bleeding episode, and hemodynamic data have shown that a dosage of 500 mg/h allows a more marked reduction of portal pressure versus the usual dosage of 250 mg/h. AIM: to assess if the 500 mg/h dosage is associated with an improved outcome. METHODS: sixty-two patients with variceal bleeding were included in the study. Patients were randomized to receive the usual dosage of SMT (group I: 250 mg/h), or a double dosage (group II: 500 mg/h), together with emergency endoscopic sclerotherapy. RESULTS: the control of the bleeding episode was similar in both groups of patients. Early rebleeding was less frequent in patients receiving double vs. single dosage of SMT (p = 0.06). When considering patients with advanced liver disease (Child-Pugh B or C) early rebleeding was significantly less frequent in patients receiving the 500 mg/h dose of SMT (39 vs. 13%, p = 0.03). CONCLUSIONS: the perfusion of higher doses of SMT (500 mg/h) in association with emergency sclerotherapy in patients with cirrhosis and esophageal hemorrhage significantly decreases the rate of early rebleeding in patients with more advanced stages of liver disease.

Acute Disease↗
PubMed2005

Norfloxacin decreases bacterial adherence of quinolone-resistant strains of Escherichia coli isolated from patients with cirrhosis.

BACKGROUND: Long-term administration of norfloxacin is recommended for secondary prophylaxis of spontaneous bacterial peritonitis in cirrhosis, but it may be associated with the development of quinolone-resistant bacteria in stools. However, these bacteria rarely cause infections. AIM: To assess bacterial adherence of either quinolone-sensitive or -resistant Escherichia coli obtained from stools of cirrhotic patients, as one of the main virulence factors, and its variations when sub-minimum inhibitory concentration of norfloxacin were added to the medium. METHODS: E. coli strains were co-cultured with oral epithelial cells obtained from patients in presence/absence of norfloxacin. Bacterial adherence was measured as percentage of cells exhibiting positive adherence and the number of bacteria attached to epithelial cells. RESULTS: 37 sensitive and 22 resistant E. coli strains were studied. Bacterial adherence was similar in both series (78% vs. 81%, P = N.S.), and these percentages were similarly and significantly reduced when subminimum inhibitory concentration of norfloxacin was added to the culture medium (P < 0.001). CONCLUSIONS: Bacterial adherence of E. coli obtained from patients with cirrhosis is unrelated to the sensitivity/resistance to quinolones, and is similarly reduced in both cases when subminimum inhibitory concentration of norfloxacin is added to the medium.

Anti-Infective Agents↗
PubMed2005

Aggregata andresi n. sp. (Apicomplexa: Aggregatidae) from the ommastrephid squid Martialia hyadesi in the SW Atlantic Ocean and some general remarks on Aggregata spp. in cephalopod hosts.

A new species of coccidian, Aggregata andresi, is described from the digestive tract of the flying squid Martialia hyadesi, an ommastrephid squid that lives in cold subantarctic waters in the Southwest Atlantic. Gamogonic and sporogonic stages were observed in the digestive tract of 96.5% studied hosts. Oocysts were ovoid to subspheroid in shape, 170-590 microm in length and 200-530 microm in width. Each oocyst contained approximately 45,000 sporocysts. Sporocysts measured 9.5-10 microm in length and 8-8.5 microm in width. The surface of the sporocyst wall was smooth and the cyst wall thick. Each sporocyst contained three sporozoites measuring 16-20 microm in length and 2-2.5 microm width. A. andresi is the second species of Aggregata to be reported from a nerito-oceanic cephalopod host.

Animals↗
PubMed2004

Pharmacokinetic variations of acetaminophen according to liver dysfunction and portal hypertension status.

AIM: To study the pharmacokinetic and metabolism profiles of a single dose of acetaminophen in patients with cirrhosis. METHODS: Oral acetaminophen (1000 mg) was administered to seven healthy subjects and 14 patients with cirrhosis (nine Child-Pugh A or B and five Child-Pugh C grade), being five without and nine with oesophageal varices. Plasma levels of acetaminophen and its metabolites were determined by HPLC. RESULTS: Patients showed a higher mean area under the curve concentration-time (67.4 +/- 22.4 mg h/L vs. 38.8 +/- 4.3 mg h/L; P = 0.01), a lower clearance (166.7 +/- 85.0 mL/min vs. 367.8 +/- 62.5 mL/min; P = 0.01) and higher elimination half-life (3.8 +/- 1.1 h vs. 2.0 +/- 0.4 h; P = 0.01) of acetaminophen than healthy volunteers. The appearance in blood and the urinary excretion of metabolites in patients did not differ from healthy subjects. Absorption profile was faster in patients. Patients with lower mean and systolic arterial pressure had lower AUC of acetaminophen, independently of liver dysfunction stage. CONCLUSIONS: Patients with cirrhosis had a higher AUC and lower clearance of acetaminophen. Acetaminophen attained earlier therapeutic concentrations in patients with oesophageal varices. Mean and systolic arterial pressures were significantly associated with AUC suggesting the importance of the haemodynamic function on the pharmacokinetics of acetaminophen in patients with cirrhosis.

Acetaminophen↗
PubMed2004

[Genotype and phenotypic expression of hereditary hemochromatosis in Spain].

INTRODUCTION: The prevalence of C282Y homozygosity in patients with hereditary hemochromatosis (HH) has been reported to be markedly lower in the Mediterranean Basin than in northern Europe. In Spain, the available data are contradictory and limited to small series in specific regions. The objective of this study is to determine the prevalence of the 2 main HFE gene mutations in a large series of unrelated Spanish patients with HH from different geographical origins. PATIENTS AND METHOD: The criteria for HH diagnosis were: repeat serum transferrin saturation index (> 45% plus C282Y homozygosity and/or hepatic iron index (> 1.9 of dry liver weight in non-cirrhotic patients or (> 4.1 in patients with liver cirrhosis. Cases in related individuals were excluded. Demographic data, clinical expression, iron parameters and HFE gene mutations (C282Y and H63D) were assessed in 222 patients. RESULTS: A total of 83.3% of patients were C282Y homozygous and 5% were compound heterozygous (C282Y/H63D). No significant differences in phenotypic expression or in the frequency of C282Y homozygosity were observed between patients born in the North and South of Spain. CONCLUSION: The genotypic and phenotypic expression of HH in Spain is very similar to that reported in Northern Europe. Thus, the genetic heterogeneity described in some Southern European regions cannot be considered a common feature to all countries of the Mediterranean Basin.

Female↗
PubMed2004

Intra- and interspecific competition between biotypes B and Q of Bemisia tabaci (Hemiptera: Aleyrodidae) from Spain.

Biotypes B and Q of Bemisia tabaci (Gennadius), collected from the islands of Tenerife and Majorca respectively, were exposed to competition conditions on tomato cv. Marmande in the laboratory. Both biotypes were established in single and mixed cultures at different densities. Increased mortality of biotype Q females and immature instars was observed together with a lower rate of fecundity and progeny size compared to biotype B, when reared in single or mixed cultures. The female:male sex ratio of F1 individuals of biotype Q was higher in single than in mixed cultures. However, the sex ratio of F1 individuals of biotype B was the same in single and mixed cultures, suggesting reproductive interference. Whitefly density did not affect interspecific interactions. It had a moderate effect on developmental rate of both biotypes, and on mortality of immature instars and progeny size of biotype B only. The results indicate that under laboratory conditions the studied biotype B should displace biotype Q.

Animals↗
PubMed2004

Bacterial DNA activates cell mediated immune response and nitric oxide overproduction in peritoneal macrophages from patients with cirrhosis and ascites.

BACKGROUND AND AIMS: Translocation of intestinal bacteria to ascitic fluid is probably the first step in the development of episodes of spontaneous bacterial peritonitis in patients with cirrhosis. We have recently reported the detection of bacterial DNA in blood and ascitic fluid from patients with advanced cirrhosis, what we consider as molecular evidence of bacterial translocation. Several studies have shown the immunogenic role of bacterial DNA in vitro, and we hypothesised that the presence of bacterial DNA could activate the type I immune response in peritoneal macrophages from these patients, leading to greater cytokine synthesis (interleukin (IL)-2 and IL-12, tumour necrosis factor alpha, and interferon gamma) and effector molecules such as nitric oxide. METHODS: Peritoneal macrophages obtained from patients with cirrhosis and culture negative non-neutrocytic ascitic fluid were collected and characterised by flow cytometry. Inducible nitric oxide synthase, nitric oxide levels, and cytokine production were measured by immunoenzymometric assays in basal and harvested conditions according to the presence/absence of bacterial DNA. RESULTS: The ability of peritoneal macrophages to synthesise nitric oxide and levels of all cytokines were significantly increased in patients with bacterial DNA. There was a positive correlation between inducible nitric oxide synthase and nitric oxide levels. CONCLUSIONS: The presence of bacterial DNA in patients with decompensated cirrhosis is associated with marked activation of peritoneal macrophages, as evidenced by nitric oxide synthesising ability, together with enhanced cytokine production.

Aged↗
PubMed2003

[Etiology of upper gastrointestinal bleeding of peptic origin: role of Helicobacter pylori and NSAIDs].

INTRODUCTION: Upper gastrointestinal bleeding continues to be a severe and frequent complication in ulcerative disease. Etiologic diagnosis in these patients is highly important in order to initiate appropriate treatment and prevent bleeding recurrence. OBJECTIVE: 1. To investigate the prevalence of Helicobacter pylori infection and use of NSAIDs in patients with upper gastrointestinal hemorrhage of peptic origin. 2. To analyze the strategy used for the diagnosis of H. pylori in our previous work. PATIENTS AND MEHTODS: Seventy-three patients with endoscopically-diagnosed upper gastrointestinal bleeding of peptic origin were included in the study. The use of NSAIDs was investigated. H. pylori infection was diagnosed if one of the following tests was positive: urease test, histology, breath test. RESULTS: H. pylori infection was found in 92% of duodenal ulcers and in 88% of gastric ulcers. Fifty-six percent of the patients had taken NSAIDs. Excluding these patients resulted in an H. pylori infection rate of 96.7%. The diagnosis was based on urease test in 46%. In the remaining patients, breath test and histology were required. CONCLUSIONS: The main etiology in patients with upper gastrointestinal bleeding of peptic origin is H. pylori infection followed by the use of NSAIDs, and these two factors frequently coexist. The strategy of performing a urease test and, when this is negative, performing histological study and a breath test, is valid and allows a diagnosis of H. pylori infection to be made even if patients are receiving treatment that could make diagnosis difficult.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Occurrence of recombinant genotypes of Anisakis simplex s.s. and Anisakis pegreffii (Nematoda: Anisakidae) in an area of sympatry.

The anisakid nematode populations collected from fish and stranded cetaceans along from Iberian Peninsula waters were morphologically identified as corresponding to the Anisakis simplex complex. In order to realise their molecular identification and to analyse the extent of genetic variation, the entire ITS (ITS1, 5.8S rDNA gene and ITS2) and the mitochondrial small subunit of rRNA were pcr-amplified and sequenced. Digestions of the amplified its region with HinfI and HhaI allowed the identification of three different genotypes, belonging to A. simplex s.s., A. pegreffii and a yet not described recombinant genotype. The ITS sequences of the recombinant genotypes showed the presence of heterozygotes C/T at position 240 and 256 of the aligned sequence. Otherwise, the analysis of mtDNA sequences showed the existence of a different parental origin for recombinant genotypes. In order to check if they can be the products of a polymorphism normally occurring both in A. pegreffii and in A. simplex s.s., and/or the existence of an incomplete concerted evolution, three samples were also collected as controls in isolated geographic areas, where sympatric coexistence between A. simplex s.s. and A. pegreffii does not occur. The results supports the hypothesis that the recombinant individuals may be a product of interspecific hybridisation, and describe the Iberian Peninsula waters as a hybrid zone for the two sibling species.

Animals↗
PubMed2002

Malabsorption syndrome observed in the common octopus Octopus vulgaris infected with Aggregata octopiana (Protista: Apicomplexa).

Octopus vulgaris infected with Aggregata octopiana were collected from an open-water culture system in the Ría of Aldán (NW Spain). Digestive tract infection values were determined with the use of a Neubauer chamber by counting the number of A. octopiana sporocysts. After determining enzyme activity values by the colorimetric Api-Zym system Biomerieux, one representative enzyme of glycosidases, peptid hydrolases and phosphoric hydrolases showing high activity was spectrophotometrically analysed. The enzymes were maltase and leucine-aminopeptidase (LAP) involved in the absorption process, and acid phosphatase, a lysosomic enzyme, respectively. Enzymatic activity of maltase and LAP decreased significantly, with increased sporocyst counts. However, acid phosphatase activity increased with severity of infection, indicating the presence of degradative enzymes from phagocytic cells in the infected area. A detrimental effect on gastrointestinal function may result from a decrease or malfunction of absorption enzymes. The results suggest a malabsorption syndrome resulting from parasitic infection.

Acid Phosphatase↗
PubMed2002

Observations on associated histopathology with Aggregata octopiana infection (Protista: Apicomplexa) in Octopus vulgaris.

Gamogony and sporogony of Aggregata octopiana were commonly observed during histological examination of the digestive tract of wild Octopus vulgaris from Ria de Vigo (NW Spain). A. octopiana infected noncuticularized caecum and intestine, and cuticularized oesophagus and crop. Infection was also observed in the gills and in covering mesenterium, mainly of the digestive gland and gonad. Histological and ultrastructural lesions associated with A. octopiana included host cell hypertrophy with nuclear displacement, inflammation, phagocytosis, ulceration and destruction of organ architecture. The possible existence of a malabsorption syndrome in the host is deduced.

Animals↗
PubMed2002

Scratching the sporocyst surface: characterisation of European Aggregata species by atomic force microscopy.

The application of atomic force microscopy to the understanding of surface structure and atomic-scale measurements on the sporocyst of European Aggregata species, intracellular coccidia of the cephalopods Octopus vulgaris and Sepia officinalis, is presented here. Using the roughness mean surface (RMS) as an index, we reveal texture to be a key parameter for characterisation of the sporocyst surface properties, which resolve the historical synonymy within the European Aggregatidae. Roughness measurements from RMS algorithms may also be an important diagnostic taxonomic character for the differentiation of Aggregata species in the future.

Algorithms↗
PubMed2001

Fitness of the marine parasitic nematode Anisakis simplex s. str. in temperate waters of the NE Atlantic.

In temperate waters of the NE Atlantic, third-stage larvae of Anisakis simplex sensu stricto collected from 3 paratenic host species were identified by restriction fragment length polymorphisms. The condition of wild larval infrapopulations was assessed by examining morphometric and growth characteristics. The differentiation patterns and the excretory/secretory products of larvae grown in vitro were also examined. An extensive morphometric, growth and differentiation variability was found between parasite larvae collected from different paratenic host sources. Nematode infrapopulation larvae from the squid comprise those smaller individuals with the lowest values of survival rates and moult success. It may be then concluded that the fitness of A. simplex s. str. larvae is not the best possible in the squid, which impaired the competitiveness of the parasite and its chances of developing into an adult. This suggests that the microenvironments impaired by the paratenic host may provide larval infrapopulations with unique ecological factors probably influencing its recruitment to the final host populations.

Animals↗
PubMed2001

Anisakis infestation in marine fish and cephalopods from Galician waters: an updated perspective.

A total of 2,673 fresh specimens of cephalopod and fish representing 35 species were obtained from commercial local fisheries in Galician waters (NW Spain). They were examined for anisakid nematodes by digestion of the muscle and elution of the viscera and whole body cavity. All larval nematodes recovered were identified by light microscopy and multilocus electrophoresis as belonging to the species Anisakis simplex sensu stricto and A. pegreffii. Encysted larvae mostly occurred in the viscera but were also found in the flesh of squid and fish. Demographic values for larval nematodes are discussed in relation to host preferences and the ecological niche of both anisakid species at the sampling area. Primary recommendations are also expressed concerning the effects of current fishing and aquaculture practices on the Anisakis problem.

Animals↗
PubMed2001

Genetic divergence and reproductive isolation between Anisakis brevispiculata and Anisakis physeteris (Nematoda: Anisakidae)s.

In order to assess the taxonomic status of Anisakis brevispiculata Dollfus, 1966 population samples of this taxon from central and south-eastern Atlantic ocean were compared at 22 enzymatic loci with samples belonging to Anisakis physeteris Baylis, 1923 from the Mediterranean sea and central-eastern Atlantic ocean. Very low interpopulational genetic divergence was observed both within A. brevispiculata (average D(Nei) = 0.008) and within A. physeteris (D(Nei) = 0.009) despite the geographic distance among the samples, indicating high levels of gene flow in both taxa. On the other hand, the average genetic distance between A. brevispiculata and A. physeteris was found to be D(Nei) = 0.80, a value generally observed between well differentiated congeneric species. The reproductive isolation between A. brevispiculata and A. physeteris is indicated by the following observations: (1) no F(1) hybrids or recombinant genotypes were until now observed; and (2) the two Anisakis species do not seem to share their definitive hosts. The main definitive host of A. brevispiculata is the pygmy sperm whale (Kogia breviceps), while for A. physeteris it is the sperm whale (Physeter catodon). Only adult males differ slightly in spicule length, while females and larval stages are not differentiated morphologically. Both A. brevispiculata and A.physeteris show a type II larva. The correct recognition of A. brevispiculata from A. physeteris and from other Anisakis species studied, in either sexes and at any life stage, is made easy by allozyme markers (e.g. Icdh, Gapdh, Sod-1, Np, Aat-2, Adk-2, fEst-2, PepB, PepC-2, Mpi). Diagnostic keys, which can be used for routine identification in the field of these Anisakis worms, based on genetic markers, are given.

Animals↗