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Biomedical subjects

C Cruz

Publications and source records attributed to C Cruz.

At least 19 recordsLinked to original sources
PubMed2003

Occurrence of Kudoa sp. (Myxozoa) in Trachurus trachurus L. (osteichthyes) in Portugal.

Specimens of Trachurus trachurus L., obtained monthly in a fish market of Oporto from October 1998 to August 1999, were examined for the presence of Kudoa in the muscle. Kudoa sp. spores were found in 84.7% of the specimens (n = 209). The prevalence was not significantly different between seasons and was not related to the host's length. The infection does not seem to have negative effects on the fish quality once no macroscopic pseudocysts or myoliquefaction were detected.

Animals↗
PubMed2003

Multicentre surveillance of antimicrobial resistance in enterococci and staphylococci from Colombian hospitals, 2001-2002.

Invasive isolates of staphylococci and enterococci were collected from 15 tertiary care centres in five Colombian cities from 2001 to 2002. A total of 597 isolates were available for analysis. Identification was confirmed by both automated methods and multiplex PCR assays in a central laboratory. Staphylococcus aureus and coagulase-negative staphylococci (CoNS) corresponded to 49.6% and 29.6% of isolates, respectively, and 20.8% were identified as enterococci. MICs of ampicillin, ciprofloxacin, chloramphenicol, erythromycin, gentamicin, linezolid, oxacillin, rifampicin, teicoplanin, tetracycline, trimethoprim/sulfamethoxazole (SXT) and vancomycin were determined using an agar dilution method as appropriate. Screening for vancomycin-resistant S. aureus was also carried out on brain-heart infusion agar plates supplemented with vancomycin. The presence of mecA and van genes was investigated in methicillin-resistant staphylococci and glycopeptide-resistant enterococci (GRE), respectively. All staphylococci were susceptible to vancomycin, teicoplanin and linezolid. No VISA isolates were found. In S. aureus and CoNS, the lowest rates of resistance were found for SXT (7.4%) and chloramphenicol (10.7%), respectively. Resistance to oxacillin in S. aureus and CoNS was 52% and 73%, respectively. The mecA gene was detected in 97.5% of methicillin-resistant S. aureus isolates. In enterococci, resistance to glycopeptides was 9.7%: vanA (58.3%) and vanB (41.7%) genes were found. Pulsed-field gel electrophoresis indicated that the GRE isolates were closely related. Rates of resistance to ampicillin, ciprofloxacin, chloramphenicol, rifampicin and high levels of gentamicin and streptomycin were 9.7%, 27.4%, 8.9%, 43%, 17% and 28.2%, respectively. All enterococci were susceptible to linezolid.

Anti-Bacterial Agents↗
PubMed2003

Rectangular to hexagonal columnar phase transition exhibited by a biforked mesogen.

We present the structural study of a biforked compound exhibiting a Colr-Colh phase transition. This study was performed by means of DSC, optical microscopy, X-ray diffraction, dilatometry and molecular modelling. The molecular packing within the two columnar mesophases of this compound is discussed. For the first time, it is shown that the clusters of adjacent molecules which form the elementary section of a column are tilted with respect to the columnar axis in the rectangular mesophase. From the whole set of experimental data, the number of molecules in a columnar section is found to be about 5 in the rectangular mesophase, and 4 in the hexagonal one. The transition between the two columnar mesophases is discussed with respect to its slow kinetics.

Journal Article↗
PubMed2003

Continuous flow peritoneal dialysis: a new double lumen catheter.

Continuous flow peritoneal dialysis (CFPD) is a therapy originally utilized in the sixties. It was then abandoned because of technical reasons, but, today, a new interest in this technique is emerging, because of new technical solutions and new hardware capabilities. CFPD is a peritoneal dialysis technique in which a certain amount of fluid is maintained in the peritoneal cavity, while a continuous inflow and outflow is provided via twin catheters or through a double lumen catheter. In this paper a new double lumen catheter is presented. The catheter is characterized by the presence of a diffuser in the inflow lumen, while a standard coiled shape characterizes the outflow lumen. The diffuser allows the use of high dialysate flows without peritoneal damage and with an excellent distribution of the fluid. The other feature of the catheter is the removable hub which allows for an easy subcutaneous tunneling of the catheter with a subsequent connection to the y segment. The special shape also guarantees a minimum recirculation during treatment. Data obtained in the first implanted catheter showed a progressive increase in small solute clearances in relation to an increase of the flow and the tidal volume in the peritoneal cavity. In particular, urea clearances up to 48 ml/min and creatinine clearances up to 39 ml/min were obtained. No major complications were observed after one year of use of the catheter.

Catheters, Indwelling↗
PubMed2003

Enterocytic columnar non-goblet cells of Barrett's esophagus--an immunohistochemical demonstration of association with malignant evolution.

Barrett's epithelium (BE), the esophageal columnar-lining with intestinal differentiation, is a premalignant condition predisposing to adenocarcinoma. Columnar cells are the prevalent element of BE, but the hallmark of intestinal differentiation is the goblet population that defines the specialised columnar epithelium (SCE). We have demonstrated that columnar cells adjacent to Barrett's adenocarcinoma (BA) exhibit enterocytic features in areas with and without SCE. Nevertheless, the relationship between malignancy and the presence of these elements is not established. To investigate whether intestinal differentiated cells, other than goblet cells, are associated to neoplasia we compared the prevalence of enterocytic features in columnar elements with and without associated BA through the use of sucrase-isomaltase (SI) immunoreactivity in 31 columnar esophageal segments (CLES) and 12 BA. In metaplasia, SI was only expressed at the columnar cells. Apical staining was exclusive of CLES with SCE. SI was present at the cytoplasm in 22.2% of CLES without SCE. Apical SI occurred in BE with and without carcinoma, similarly in areas with and without SCE (p = 0.11 and p = 0.50, respectively). In areas with SCE, columnar cells with apical SI were more frequent in cases of BE adjacent to carcinoma than in cases without neoplasia but the difference did not reach significance (p = 0.053). In areas without SCE, apical SI was significantly (p = 0.01) more frequent in cases with carcinoma. Apical SI was equally found in neoplastic as in metaplastic areas, with and without SCE, (p = 0.07 and p = 0.40, respectively). In conclusion this study on the frequency of SI on CLES with and without neoplasia demonstrated that additionally to SCE, metaplastic enterocytic cells are also associated with malignancy. It also confirmed that the presence of intestinal features are underestimated if only goblet elements are used for its identification, reinforcing the utility of the immunohistochemical recognition of enterocytic characteristics for establishing the diagnosis of BE.

Adenocarcinoma↗
PubMed2002

Vanilloid receptor 1 expression in the rat urinary tract.

Previous findings have shown that the capsaicin sensitivity of sensory fibres is due to the expression of a specific membrane protein, the vanilloid receptor type 1 (VR1). In the present work we studied the distribution, morphology and the neurochemical content of nerve fibres expressing this receptor in the rat urinary tract. Immunolabelling was performed against the VR1 and the positive fibres were examined by light and electron microscopy. Colocalisation of VR1 and substance P or calcitonin gene-related peptide immunoreactivities, and isolectin B4 binding, was evaluated under the confocal microscope. In addition, the effect of intravesical administration of resiniferatoxin, an ultra-potent vanilloid receptor agonist, in the receptor expression in the bladder was also studied. Numerous VR1-immunoreactive fibres were found in the mucosa and muscular layer of the entire urinary tract except the kidney. In the bladder, most fibres were also substance P- or calcitonin gene-related peptide-immunoreactive but did not bind isolectin B4. Under the electron microscope VR1 immunoreactivity was confined to unmyelinated axons and varicosities containing small clear and large dense-core synaptic vesicles. They occurred beneath or among epithelial cells or closely apposed to smooth muscle cells. Intravesical resiniferatoxin decreased VR1 immunoreactivity transiently. These data indicate that primary sensory fibres expressing VR1 are extremely abundant in the rat urinary tract and that, in contrast to the skin, they belong almost exclusively to the peptide-containing sub-population of primary afferents. As capsaicin-sensitive bladder afferents are involved in nociception and reflex micturition control, the numerous free terminal nerve endings expressing VR1 in the mucosa seem more adequate to accomplish the former function. However, the close apposition between VR1-expressing fibres and smooth muscle cells suggests that they may also encode the tonus of the muscular layer.

Animals↗
PubMed2002

Recurrent columnar-lined esophageal segments--study of the phenotypic characteristics using intestinal markers.

Barrett's metaplasia is recognized by specialized columnar epithelium on the distal esophagus. The events involved in the transformation from squamous to Barrett's epithelium remain unclear. The present study describes the characteristics observed during the recurrence of four cases of columnar-lined esophagus. Red velvet, gastric-like, esophageal mucosa was observed to develop above the anastomosis during follow-up of four patients submitted to surgery for esophageal and junctional adenocarcinoma. The areas of recurrence were associated with reflux symptoms and inflammation, with ulceration in two cases. Biopsies from the upper gastrointestinal endoscopies were examined histologically using periodic acid-Schiff/Alcian blue to detect acid mucins and a monoclonal antibody raised against the enterocytic enzyme sucrase-isomaltase. In all cases the recurrent columnar-lined segments displayed intestinal features recognized morphologically, histochemically, and/or immunohistochemically. There was no evidence of specialized columnar epithelium in three cases. The fourth patient developed specialized columnar epithelium during the tenth year of surveillance. The presence of AB-positive columnar cells was a frequent and early event. Columnar cells with unequivocal apical sucrase-isomaltase were observed only in association with specialized columnar epithelium. Four conclusions were reached: that the development of columnar-lined mucosa without specialized columnar epithelium may be the earliest event in Barrett's metaplasia; that histochemistry is a useful method of recognizing a population with cryptic intestinal features; that acid mucin secretion precedes the production of enterocytic enzymes by columnar cells; and that a cell population with enterocytic differentiation, as assessed by sucrase-isomaltase expression, is associated with the development of specialized columnar epithelium. These characteristics of Barrett's esophagus development are clinically relevant as they suggest that patients with columnar-lined esophagus without specialized columnar epithelium may acquire 'true' intestinal phenotype, justifying them being considered as high- risk patients.

Adenocarcinoma↗
PubMed2002

Myoarchitecture and vasculature of the heart ventricle in some freshwater teleosts.

The morphological characteristics of the ventricular myocardium and of coronary vascularization were studied in three freshwater teleost species, Piaractus mesopotamicus, Colossoma macropomum and Clarias gariepinus (African catfish), by correlating their ventricular shapes and swimming habits. In Piaractus mesopotamicus and Colossoma macropomum, species with highly active swimming habits, the cardiac ventricle showed a pyramidal shape and a richly vascularized myocardium consisting of an outer compact layer and inner spongy layer. In Clarias gariepinus, a less active species, we observed a saccular ventricle with a mixed myocardium and coronary arteries, in contrast to the ventricular structure of other species described in the literature.

Animals↗
PubMed2002

Occurrence and maturation of Rhabdochona gnedini (Nematoda: Rhabdochonidae) in the barbels of the Sousa River, Portugal.

Data on the seasonal occurrence and maturation of Rhabdochona gnedini Skrjabin, 1946 in its definitive host, the barbel Barbus bocagei, from the Sousa River, in northern Portugal, are presented. Monthly samples were taken from November, 1998 to October, 1999. A total of 178 fish specimens were inspected. R. gnedini occurred with high prevalences during whole year, attaining the highest values of intensity in summer (overall prevalence and mean intensity 85% and 31, respectively). A clear annual cycle of maturation was observed; females with mature eggs occurred in spring and summer. Unidentified Rhabdochona larvae were recorded from the trichopteran larvae Hydropsyche sp. (prevalence and intensity 29% and one to 34, respectively). These larvae are presumptive intermediate host for R. gnedini.

Animals↗
PubMed2002

Pathogenicity of missense and splice site mutations in hMSH2 and hMLH1 mismatch repair genes: implications for genetic testing.

BACKGROUND: In hereditary non-polyposis colorectal cancer, over 90% of the identified mutations are in two genes, hMSH2 and hMLH1. A large proportion of the mutations detected in these genes are of the missense type which may be either deleterious mutations or harmless polymorphisms. AIM: To investigate whether nine missense and one splice site mutation of hMLH1 and hMSH2, in 10 kindreds with a familial history of colorectal cancer or young age of onset, could be interpreted as pathogenic. METHODS: Clinical and genetic characteristics were collected: (i) evolutionary conservation of the codon involved; (ii) type of amino acid change; (iii) occurrence of mutation in healthy controls; (iv) cosegregation of mutation with disease phenotype; (v) functional consequences of gene variant; and (vi) microssatellite instability and immunoexpression of hMSH2 and hMLH1 analysis. RESULTS: Seven different missense and one splice site mutation were identified. Only 1/8 was found in the control group, 2/7 occurred in conserved residues, and 5/7 resulted in non-conservative changes. Functional studies were available for only 2/8 mutations. Segregation of the missense variant with disease phenotype was observed in three kindreds. CONCLUSION: In the majority of families included, there was no definitive evidence that the missense or splice site alterations were causally associated with an increased risk of developing colorectal cancer. Until further evidence is available, these mutational events should be regarded and interpreted carefully and genetic diagnosis should not be offered to these kindreds.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Additional evidence that genetic variation of MAO-A gene supports a gender subtype in obsessive-compulsive disorder.

Studies have recently reported a sexually dimorphic association between obsessive-compulsive disorder (OCD) and a polymorphism related with variations in MAO-A activity. These observations suggest the possibility of gender differences in genetic susceptibility for OCD. We thus reexamined the MAO-A/EcoRV polymorphism in a sample of 122 OCD patients and 124 healthy subjects. An excess of allele 1 in OCD females with major depression disorder was confirmed as previously reported. This difference was more strongly associated with OCD females than males in the total sample. Finally, we analyzed a sample of 51 OCD trios. Haplotype-based haplotype relative risk (HHRR) analysis of the inheritance of the MAO-A variants revealed in the female probands that 14 out of 19 transmitted the allele 1, providing significant evidence for an allelic association between OCD and MAO-A gene. In conclusion, our findings may provide molecular evidence to identify a clinically meaningful gender subtype. However, an effort should be made to replicate the analysis in larger samples of informative parents using strategies such as transmission disequilibrium test to allow definite conclusions.

Adult↗
PubMed2001

HERC3 binding to and regulation by ubiquitin.

Members of the HERC (domain homologous to E6 associated protein carboxy-terminus and RCC1 domain protein) family may function both as guanine nucleotide exchange factors and E3 ubiquitin ligases. Here we identify an unstudied member, HERC3. This protein was recognized by specific antibodies in different cell types. HERC3 was located in the cytosol and in vesicular-like structures containing beta-COP, ARF and Rab5 proteins. Involvement of HERC3 in the ubiquitin system was suggested by its ability to interact with ubiquitin. The conserved cysteine in HECT proteins was not essential for this non-covalent binding. Moreover, HERC3 was a substrate of ubiquitination being degraded by the proteasome. These observations indicate a fine regulation of HERC3 and suggest a role in vesicular traffic and ubiquitin-dependent processes.

Animals↗
PubMed2001

Genomic characterization of wild-type measles viruses that circulated in different states in Brazil during the 1997 measles epidemic.

Despite the marked reduction in the incidence of measles in Brazil, a measles epidemic occurred in this country in 1997. The measles cases observed during this epidemic began to reappear in large numbers in São Paulo, and spread to Rio de Janeiro and other Brazilian states. In the present study molecular biology techniques were used for the detection and genomic characterization of measles viruses from clinical samples such as urine and nasopharyngeal secretions collected in the states of Rio de Janeiro, Minas Gerais and Paraná, during the 1997 epidemic. RT-PCR and nucleotide sequence analysis of part of the carboxyl-terminal region of the nucleoprotein gene of measles viruses obtained directly from clinical samples or from infected cell cultures during this epidemic classified all as wild-type of genotype D6. As the genotype D6 was identified in different Brazilian states, this study demonstrated that this genotype was circulating in Brazil during the 1997 epidemic.

Adult↗
PubMed2001

Increasing levels of dietary homocystine with carotid endarterectomy produced proportionate increases in plasma homocysteine and intimal hyperplasia.

PURPOSE: The role that homocysteine may play in post-carotid endarterectomy (CEA) restenosis due to intimal hyperplasia is not well understood. This study was designed to investigate the effects of different levels of dietary homocystine on: (1) plasma homocysteine; (2) post-CEA intimal hyperplasia; and (3) levels of the methyl donor S-adenosylmethionine (SAM) and its counterpart S-adenosylhomocysteine (SAH) in the homocysteine pathway. METHODS: Male rats were fed specialized diets for 2 weeks pre- and post-CEA. Groups included control (0 homocystine added, n=9), 1.5 (1.5 g/kg homocystine added, n=10), 3.0 (3.0 g/kg homocystine added, n=9), and 4.5 (4.5 g/kg homocystine added, n=11). The rats underwent a surgical carotid endarterectomy. Endpoints included; plasma homocysteine, intimal hyperplasia, replicative index using with alpha-SM actin and BrdU, hepatic SAM levels, SAH levels, and the hepatic activities of methylenetetrahydrofolate reductase (MTHFR) and cystathionine beta-synthase (CBS). RESULTS: Increasing dietary homocystine produced a proportionate increase in plasma homocysteine and an increase in intimal hyperplasia. Regression analysis of plasma homocysteine levels and intimal hyperplasia showed a significant correlation (r=0.71,P=0.003). Plasma homocysteine levels above 15 microM were associated with significant increases in intimal hyperplasia above 6.5% (P=0.04). Elevation of plasma homocysteine levels to moderate levels (5-25 microM) resulted in significant post-CEA intimal hyperplasia. Cellular analysis of the area of intimal hyperplasia in all diet groups showed comparable amounts of cells positive for alpha-SM actin. However, with increasing levels of dietary homocystine and plasma homocysteine there was an increase in replicative index (P<0.001) as determined by BrdU staining. Increasing dietary homocystine increased plasma homocysteine and was followed by increases in the replicative index thus producing increased intimal hyperplasia and lumenal stenosis. In hepatic measurements the 1.5 and 3.0 g/kg homocystine diets caused: increased liver activity of MTHFR (P=0.03) and decreased hepatic levels of SAM, SAH and SAM/SAH ratios compared to controls. Homocystine treatment did not cause significant alterations in CBS levels (P=0.992). These studies also showed no correlation of the MTHFR and CBS enzymes with plasma homocysteine levels or intimal hyperplasia. However, hepatic levels of SAM showed significant negative correlations with plasma homocysteine (r=-0.58; P=0.006) and with BrdU percentages of cellular proliferation (r=-0.69; P=0.06). CONCLUSION: The degree of post-CEA intimal hyperplasia in a rat model is directly related to the plasma level of homocysteine. The hyperplastic effects of homocysteine may be mediated in part by a physiological insufficiency of methyl donors as shown by decreases in SAM. Thus, increasing levels of plasma homocysteine enhanced and accelerated the smooth muscle cell response after CEA which led to increased intimal hyperplasia and lumenal stenosis.

Animals↗
PubMed2001

Association study of the serotonin transporter gene polymorphism in obsessive-compulsive disorder.

The hypothesis implicating the serotonergic system in the pathophysiology of obsessive-compulsive disorder (OCD) is supported by the therapeutic efficacy of selective serotonin reuptake inhibitors (SSRIs). Since SSRIs act on the serotonin transporter (5-HTT), it has been suggested that the 5-HTT gene (SCL6A4) could be a good candidate for OCD. The SCL6A4 gene has a 44-bp insertion/deletion polymorphism in its promoter region (5-HTTLPR). Previous studies have revealed an association between OCD and the l allele. We analysed the 5-HTTLPR polymorphic system in 115 Mexican OCD patients and 136 controls. No significant association was found between l allele and OCD (chi2 = 1.54, d.f. = 1, p = 0.21). Furthermore, we assessed alternative methods that employ family-based designs in a sample of 43 trios. Haplotype-based haplotype relative risk and transmission disequilibrium analysis did not show a preferential transmission of l allele to OCD probands. Our results indicate the need to analyse larger samples using family-based methods.

Adult↗