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C Carmona

Publications and source records attributed to C Carmona.

At least 37 records · Page 2Linked to original sources
PubMed1998

Characterization and partial purification of a leucine aminopeptidase from Fasciola hepatica.

An aminopeptidase activity capable of hydrolyzing different aminomethylcoumarin amino acids, but mainly leucine-7-amino-4-methylcoumarin (Leu-NHMc), was detected in deoxycholic soluble extracts from adult Fasciola hepatica. The enzyme (EC 3.4.11.1) was partially purified by gel filtration and EAH-Sepharose affinity chromatography using bestatin as a ligand. Results obtained by gel filtration, direct fluorogenic substrate analysis in polyacrylamide gel, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggest that in a native form the enzyme might be aggregated as a high molecular weight complex. By affinity chromatography on concanavalin A Sepharose, the enzyme did not bond to the column showing that it lacks mannose residues. The F. hepatica aminopeptidase was characterized as a metalloproteinase based on its activation by Mn2+ and Mg2+, and its inhibition by EDTA, 1,10-phenanthroline, and bestatin. It has an optimal activity at a pH between 8.0 and 8.5. Histochemical localization revealed strong leucine naphthylamidase activity at the cells lining the gut epithelium of the parasite.

Animals↗
PubMed1997

Principles of the surgical approach in human liver cystic echinococcosis.

Ultrasonography (USG) has recently contributed much to the diagnostic of hepatic cystic echinococcosis (CE). The use of portable ultrasonograph allowed us to perform a community survey among 9482 people living in a high risk area for CE in the Florida Department (Uruguay). Positive USG results were found in 123 asymptomatic patients. 48 out of 51 USG positive cases were surgically confirmed and 3 were found to be false positive. The results of this survey allowed us to propose a new classification of the echographic imaging based on the parasite's various evolutive and involutive stages. The Echinococcus granulosus cyst size was compared with the parasite's evolutive stages. The cyst's segmentary topography and the related risk of CE is evaluated. The importance of cystic-biliary communication is pointed out and its rational surgical treatment described. Finally, an algorithm is presented facilitating the choice of a rational treatment.

Adolescent↗
PubMed1997

Coproantigen detection in dogs experimentally and naturally infected with Echinococcus granulosus by a monoclonal antibody-based enzyme-linked immunosorbent assay.

A sandwich ELISA for the detection of Echinococcus granulosus coproantigen in formalin and heat-treated faecal supernatants of dogs was developed. The assay used affinity-purified polyclonal antibodies obtained from rabbits hyperimmunised with E. granulosus excretory/secretory antigens and biotinylated monoclonal antibody EmA9 produced against adult E. multilocularis somatic extract. The test was sensitive to 7 ng and 2.3 ng of E. granulosus protein and carbohydrate/ml of faecal supernatant, respectively. Thirteen helminth-free dogs were infected with different amounts of E. granulosus protoscoleces and the presence of coproantigen was monitored during the prepatent period until day 35 post-infection, when they were necropsied. Faecal antigen levels started to rise above the normal range between days 10 and 20 post-infection, and typically peaked at the end of the experiment. All the dogs, bearing from 3 to 67,700 worms, showed positive values in the ELISA during the prepatent period. One dog experimentally infected with Taenia hydatigena metacestode and harbouring three worms, tested positive only after the prepatent period at day 52. The test was applied to 98 stray dogs. The ELISA detected all of four dogs naturally infected with E. granulosus, two dogs with patent infections of T. hydatigena and two dogs with no cestode infections, showing a sensitivity of 100% and a specificity of 96%.

Animals↗
PubMed1997

Proteinases secreted by Fasciola hepatica: time course of the inhibitory effect of serum from experimentally infected rabbits demonstrated by gelatin-substrate polyacrylamide gel electrophoresis.

Fasciola hepatica secretes proteolytic enzymes to aid it to penetrate and migrate through the host tissues. Two of these proteinases have been purified and shown to be cathepsin L-like, and are termed, CL1 (27.5 kD) and CL2 (29 kD). The immunogenicity of these proteinases was investigated over the course of an experimental infection and following drug treatment. Four groups of rabbits were studied: group 1: orally infected with 50 metacercariae; group 2: infected and treated 8 weeks after infection; group 3: infected, treated at week 8 and reinfected at week 13 and group 4: non-infected control group. Sera were collected weekly from each group until week 20 postinfection. CL1 and CL2 were incubated with the different sera and then analysed by gelatin substrate polyacrylamide gel electrophoresis (GS-PAGE). Analysis of groups 1, 2 and 3 showed that CL1 and CL2 neutralizing antibodies appear at week 5 post-infection. In group 1, these remained throughout the 20 weeks of infection. In group 2, neutralizing antibodies disappeared at week 13, that is, 5 weeks after anti-Fasciola treatment. In group 3, CL1 and CL2 neutralizing antibodies disappeared at week 13 but reappeared by week 15, that is 2 weeks after reinfection. Pooled sera from group 4, showed no inhibitory capacity. ELISA results using CL1 and CL2 as antigen, correlate very well with the inhibitiory time course observed by GS-PAGE. These results suggest that purified cathepsin Ls are antigenic molecules recognized early in the infective process and capable of inducing a specific humoral response, strong enough to neutralize, at least partially, their enzymatic activity.

Animals↗
PubMed1997

Partition coefficients of indoles and betacarbolines.

Partition coefficients for substituted indoles and betacarbolines were determined in octan-1-ol/water and cyclohexane/water. A comparative study of the results in both systems allows us to discuss the effects played by the different molecular structures, substituents, and aromaticity on the distribution properties of these compounds. In particular, the hydrogen-bond donor (HBD) and hydrogen-bond acceptor (HBA) properties of these solutes were characterized and compared with those of structurally related compounds. The Abraham solute descriptors were estimated and partition coefficients (log P) calculated and compared with the experimental values. The results show that the HBD properties are similar for indoles and betacarbolines, and the HBA capacity, as expected, is significantly enhanced by the contribution of the extra pyridinic or piperidinic ring in betacarbolines. The effects of the substituent groups are presented in relation to their contribution to the distribution properties of the compounds studied.

Carbolines↗
PubMed1997

Proteinases secreted by Fasciola hepatica degrade extracellular matrix and basement membrane components.

The invasive stages of the parasitic trematode Fasciola hepatica release proteinases into the medium in which they are maintained. In this study, we investigated the interaction of F. hepatica excretory/secretory (E/S) products and 2 cysteine proteinases (CL1 and CL2) purified from these products with extracellular matrix and basement membrane macromolecules. Fasciola hepatica E/S products contained collagenolytic activity on fibrillar types I and III collagen as well as basement membrane type IV collagen. CL1 and CL2 were capable of degrading acid-soluble type III and type IV collagen but not insoluble type I collagen. In contrast, neither the E/S products nor the purified CL1 and CL2 showed elastinolytic activity. Fibronectin and laminin were degraded by E/S products and by CL1 and CL2. Sequence analysis of fibronectin degradation products showed that the fragments obtained corresponded to complete biologically active domains. These results indicate that the cysteine proteinases secreted by F. hepatica may be involved in the process of tissue invasion by the parasite.

Amino Acid Sequence↗
PubMed1997

[Motor neuron disease and HIV].

Motor-neuron disease, in particular its commonest form (lateral amyotrophic sclerosis) is a degenerative disease of unknown aetiology and inexorable course with an estimated incidence of 0.4-1.8 per 100,000 inhabitants. In recent years great efforts have been made to discover the aetiopathogenesis of this disorder, studying genetic, viral, endocrine, toxic factors, etc. We present the case of a 30 year old man who started to develop a clinical condition compatible with motor-neuron disease 18 months after diagnosis of HIV. An extensive differential diagnosis was considered in view of this past history. Complementary tests considered necessary for diagnosis of motor-neurone disease and for exclusion of other neurological conditions related to HIV were done. After 16 months of follow-up the condition has become a clear case of ELA type motor neurone disease with no further HIV-related pathology. We discuss questions concerning the aetiopathology of the disease, based on the currently accepted viral hypothesis and describe recent findings related to both.

Adult↗
PubMed1996

Transjugular intrahepatic portosystemic shunt for the management of hepatic hydrothorax in the absence of ascites.

Hepatic hydrothorax in the absence of clinical ascites (HHAA) is a somewhat rare complication in decompensated cirrhosis. Patients with HHAA have a congenital defect in the tendinous portion of the diaphragm allowing rapid leakage of ascites into pleural cavity because of the cyclical negative intrathoracic pressure. Although several therapeutic approaches, including peritoneovenous shunt and chemical or surgical pleurodesis, have been attempted in these patients the results are largely unsatisfactory. A poor-risk surgical cirrhotic woman who was also considered not suitable for liver transplantation underwent transjugular intrahepatic portosystemic shunt (TIPS) for palliation of HHAA. After TIPS procedure hydrothorax completely resolved. TIPS can offer an attractive alternative to standard therapy in cirrhotic patients with HHAA.

Fatal Outcome↗
PubMed1996

Comparison of serodiagnostic tests and ultrasonography for cystic hydatidosis in an epidemiological study of rural Uruguay.

Cystic hydatidosis (CH) caused by Echinococcus granulosus is an important zoonosis worldwide. Several serodiagnostic and ultrasound tests are currently used for screening asymptomatic CH. The sensitivity of the serodiagnostic tests has been demonstrated by several groups to be lower than ultrasonography (US). To explain the mechanism of the difference in sensitivity, a large-scale US survey combined with an IgG4-enzyme-linked immunosorbent assay test was conducted in Uruguay. Our results suggest that certain cyst images, e.g., multivesicular cysts, may be closely associated with a high antibody response regardless of the cyst size, whereas other hydatid lesions, e.g., solid images with/without rolled parasite membranes, have lower antibody responses with a close relationship to cyst size. Seropositivity of subjects who had been treated surgically for removal of hydatid cysts in the last 5 yr was closest to that of actual CH patients, albeit free from CH by US. These findings are important for the proper use of serodiagnostic tests and US for community-based epidemiological studies.

Animals↗
PubMed1995

Molecular associations of flavins with betacarbolines and related indoles.

The interactions of a set of structurally selected betacarbolines (BC), (9H-pyrido[3,4-b]indoles) and indoles (IND) with two representative flavins (FN): riboflavin (RFN) and flavin mononucleotide (FMN) have been investigated by absorption and fluorescence spectroscopies. Spectral results provided evidence on the formation of 1:1 non-fluorescent molecular complexes, whose stability constants and other related thermodynamic parameters have been estimated from Stern-Volmer quenching analysis. The FMN complexes are somewhat more stable than the RFN complexes. The stabilities of the IND and BC complexes for a given FN follow approximately the order IND approximately tetrahydro BC < dehydro BC < fully aromatic BC. Protonation of the pyridinic nitrogen atom of BCs has a destabilizing effect, which is more pronounced for fully aromatic than for tetrahydro derivatives. The influence of structural factors on the stability of the complexes has been discussed and, aided by theoretical AM1 calculations, a qualitative model for the structure (stacking) and binding forces (cooperative localized charge transfer and dispersion forces) of the complexes has been proposed.

Carbolines↗
PubMed1994

A dipeptidylpeptidase secreted by Fasciola hepatica.

A dipeptidylpeptidase (DPP) was isolated from Fasciola hepatica by gel-filtration and ion-exchange chromatography. The exoproteinase is secreted by newly excysted juveniles, immature and mature flukes. The liver fluke DPP is a serine proteinase of molecular weight > 200 kDa and differs from previously characterized mammalian DPPs in its substrate preference and susceptibility to inactivation by inhibitors. The parasite DPP may function in the latter stages of the proteolytic digestion of host macromolecules. In this manner, the enzyme may be important in providing the parasite with dipeptides that could be absorbed through the intestine as nutrient.

Animals↗
PubMed1994

Neutralization of the activity of a Fasciola hepatica cathepsin L proteinase by anti-cathepsin L antibodies.

Fasciola hepatica secretes a cathepsin L proteinase that is suggested to play an in vivo role in immunoprotection since the enzyme can cleave host immunoglobulin. In the present report, rabbit anti-cathepsin L IgG was shown to bind to the cathepsin L enzyme and inhibit its ability to cleave IgG molecules. Cathepsin L can prevent the antibody-mediated attachment of eosinophils to newly excysted juveniles in in vitro assays; however, if anti-cathepsin L IgG are mixed with the cathepsin L prior to the addition of the enzyme to the assay, eosinophils attach to the newly excysted juveniles. Thus it is possible to prepare antibodies that can bind and disrupt the biological activity of the F. hepatica cathepsin L.

Animals↗
PubMed1994

Prediction of further hemorrhage in bleeding peptic ulcer.

OBJECTIVE: To obtain a simple mathematical model able to estimate early the risk of further hemorrhage in bleeding peptic ulcer. METHODS: A prospective study was conducted on 1567 patients admitted for acutely bleeding peptic ulcer. Ten readily available variables were tested for association with further hemorrhage, and then a logistic regression analysis was carried out. RESULTS: Further hemorrhage occurred in 312 (20%) patients. The univariate analyses showed age over 65 yr, male sex, alcoholism, associated disease, hematemesis, endoscopic bleeding stigmata and shock, and blood urea over 90 mg/dl at admission to be significantly associated with continuous hemorrhage or rebleeding (p < 0.05 to p < 0.001). When these were assessed in a multivariate logistic regression analysis, the best fitted model (likelihood ratio test = 9.9; p = 0.5) included four independent variables. Bleeding stigmata (p < 0.001; odds ratio = 3.1), shock (p < 0.001, odds ratio = 2.5), hematemesis (p < 0.001; odds ratio = 1.6) and age over 65 (p = 0.04); odds ratio = 1.3) were associated with high risk of further hemorrhage. CONCLUSIONS: Bleeding stigmata and changes in hemodynamics are confirmed as the most relevant predictors of further hemorrhage. When they are considered with hematemesis and age altogether, other clinical features loss importance for prognosis. By taking advantage of the joint influences of these variables, accuracy of prognosis improves with respect to that obtained when they are considered as individual risk factors.

Aged↗
PubMed1993

Cathepsin L proteinase secreted by Fasciola hepatica in vitro prevents antibody-mediated eosinophil attachment to newly excysted juveniles.

Cathepsin L-like activity was demonstrated in the excretory/secretory (E/S) products of Fasciola hepatica newly excysted juveniles (NEJ), 3-week-old, 5-week-old and mature flukes using the fluorogenic substituted 7-amino-4-methylcoumarin substrates Z-phe-arg-AMC, Z-arg-arg-AMC and Z-arg-AMC. Gelatin-substrate polyacrylamide gel analysis revealed that the E/S from each of these stages contained multiple proteolytic enzymes; however, the pattern of proteinases obtained for NEJ E/S differed markedly from that of all other stages examined. The four NEJ proteinases identified were inhibited by leupeptin and Z-phe-ala-diazomethyl ketone indicating that each had cathepsin L-like activity. The E/S products of all four developmental stages contain an enzyme capable of cleaving immunoglobulin at the hinge region, the activity of which is also inhibited by Z-phe-ala-diazomethyl ketone. Using in vitro cell attachment assays we show that the cathepsin L-like proteinase purified from the E/S products of adult F. hepatica can prevent the antibody-mediated attachment of eosinophil to NEJ. These experiments indicate that this proteinase has an important biological function in immune evasion.

Animals↗
PubMed1993

Efficacy of the heater probe in peptic ulcer with a non-bleeding visible vessel. A controlled, randomised study.

A controlled, randomised study was performed to evaluate the efficacy of treatment with heater probe in the prevention of rebleeding from peptic ulcer with a non-bleeding visible vessel. One hundred and one patients were randomised into two groups: patients to be treated by heater probe (n = 51) and controls without active treatment (n = 50). In the heater probe group rebleeding occurred in five patients (10%) v 13 (26%) in the control group (p = 0.03), with a comparative risk of 0.38 in favour of the heater probe group. The difference in proportions of successful treatment for each group was 16.2% in favour of the heater probe (95% CI = 2 to 31%). Haemorrhage directly related to heater probe treatment occurred in four patients. In three of them bleeding was easily controlled by further heater probe pulses. There were no other complications and no death in the heater probe group. One patient in the control group died of pulmonary embolism. No significant differences in the length of stay in hospital, blood transfusions, surgical rates, or death were found; the design of the study, however, precluded an adequate assessment of these variables, because the heater probe was an optional rescue treatment when high surgical risk patients rebled. These results suggest that the heater probe is an effective and safe procedure in the prevention of recurrent haemorrhage in peptic ulcer with a non-bleeding visible vessel.

Adult↗
PubMed1992

Cytochrome P-450terp. Isolation and purification of the protein and cloning and sequencing of its operon.

Cytochromes P-450 are extremely important in the oxidative metabolism of a variety of endogenous and exogenous compounds in pro- and eukaryotic organisms. Progress in understanding the structure and mechanism of action of this superfamily of enzymes has been hampered by the properties of the eukaryotic enzymes and the availability of only one well-characterized prokaryotic enzyme as a model. We report here the isolation of a Pseudomonas species which will utilize a monoterpene natural product, alpha-terpineol, as its sole source of carbon and energy. Approximately 1% of the soluble protein in the cell-free extract is a novel cytochrome P-450 (P-450terp). This enzyme and its associated iron sulfur protein electron carrier (terpredoxin) have been purified to homogeneity and their NH2-terminal amino acid sequences determined. The amino acid sequences of six tryptic peptide fragments of cytochrome P-450terp have also been determined. This sequence information was used to clone the gene encoding cytochrome P-450terp. Three clones representing approximately 8 kilobase pairs of unique sequences were selected and sequenced. Five non-overlapping open reading frames (ORFs) were found in the sequences, and the translated sequences were used to search the Protein Identification Resource for comparable proteins. The ORFs were identified as: 1) an alcohol dehydrogenase, 2) an aldehyde dehydrogenase, 3) cytochrome P-450terp, 4) terpredoxin reductase, and 5) terpredoxin. The identification of both the cytochrome P-450terp and terpredoxin DNA sequence was confirmed by the presence of each of the corresponding amino acid sequences found in the purified proteins. The five ORFs were bounded on both the 5' and 3' ends by consensus factor-independent terminator sequences. A consensus promoter sequence was found immediately 5' to the first ORF. These results indicate that we have sequenced the complete terp operon. Comparison of the amino acid sequence of cytochrome P-450terp to that of all other cytochromes P-450 has shown that it is the first member of the gene family CYP108. Preliminary characterization of the chemical and physical properties and the preparation of crystals of this new cytochrome P-450, suitable for x-ray diffraction analysis, indicate that it will be useful in comparison studies with other members of this class of proteins.

Alcohol Dehydrogenase↗