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Biomedical subjects

E Campos

Publications and source records attributed to E Campos.

At least 37 records · Page 2Linked to original sources
PubMed2000

Porcine reproductive and respiratory syndrome (PRRS) virus down-modulates TNF-alpha production in infected macrophages.

The effect of porcine reproductive and respiratory syndrome (PRRS) virus infection on the synthesis and secretion of TNF-alpha and other pro-inflammatory cytokines by porcine alveolar macrophages (PAM) was investigated as well as the effect that TNF-alpha has on the replication of this virus. A clear reduction of phorbol myristate acetate (PMA)-induced expression of TNF-alpha mRNA was observed in cells incubated with PRRS virus. Moreover, the presence of PRRS virus also induced a decrease in IL-1 alpha and MIP-1 beta mRNAs expression with respect to PMA-stimulated uninfected cells. According to these results, exposure to the PRRS virus led to a reduction of the TNF-alpha protein in supernatants of PMA-stimulated PAM. On the other hand, addition of recombinant porcine TNF-alpha to cultures clearly reduced virus replication; however the addition of TNF-alpha to cultures containing IFN-alpha did not result in a further reduction of the produced by IFN-alpha alone. This indicates the lack of synergy in the effect of these cytokines on viral replication.

Animals↗
PubMed2000

Usefulness of IS6110-restriction fragment length polymorphism typing of Brazilian strains of Mycobacterium tuberculosis and comparison with an international fingerprint database.

Strains of Mycobacterium tuberculosis isolated from 219 different tuberculosis patients, 115 from patients residing in Rio de Janeiro, 79 from Rio Grande do Sul and the remaining from other regions of the country, were analyzed by IS6110-restriction fragment length polymorphism fingerprinting. The IS6110-DNA patterns from these strains were highly polymorphic: 174 different patterns were observed and 25 patterns were shared by 70 isolates (32%). Most strains (93.4%) had multicopy patterns and only 17% of clustered strains had less than six IS6110 copies. Strain clustering was significantly higher for isolates from Rio Grande do Sul (36.7%) in comparison with strains from Rio de Janeiro (22.6%), but only when using high stringency during cluster analysis. Upon screening of an international database containing 3,970 fingerprints of M. tuberculosis strains, 15% of the patterns of Brazilian strains (21% of the strains) were identical to a fingerprint of an isolate from another country and one particular eight-band pattern forming the largest Brazilian cluster was detected in seven additional countries, suggesting that international transmission of tuberculosis from and to Brazil could be occurring frequently. Alternatively,preferential use of certain IS6110 integration sites could also be important in high-copy number strains, having important consequences for the use of databases for epidemiological studies on a large scale.

Bacterial Typing Techniques↗
PubMed2000

Regulation of expression of the yiaKLMNOPQRS operon for carbohydrate utilization in Escherichia coli: involvement of the main transcriptional factors.

The yiaKLMNOPQRS (yiaK-S) gene cluster of Escherichia coli is believed to be involved in the utilization of a hitherto unknown carbohydrate which generates the intermediate L-xylulose. Transcription of yiaK-S as a single message from the unique promoter found upstream of yiaK is proven in this study. The 5' end has been located at 60 bp upstream from the ATG. Expression of the yiaK-S operon is controlled in the wild-type strain by a repressor encoded by yiaJ. No inducer molecule of the yiaK-S operon has been identified among over 80 carbohydrate or derivative compounds tested, the system being expressed only in a mutant strain lacking the YiaJ repressor. The lacZ transcriptional fusions in the genetic background of the mutant strain revealed that yiaK-S is modulated by the integration host factor and by the cyclic AMP (cAMP)-cAMP receptor protein (Crp) activator complex. A twofold increase in the induction was observed during anaerobic growth, which was independent of ArcA or Fnr. Gel mobility shift assays showed that the YiaJ repressor binds to a promoter fragment extending from -50 to +121. These studies also showed that the cAMP-Crp complex can bind to two different sites. The lacZ transcriptional fusions of different fragments of the promoter demonstrated that binding of cAMP-Crp to the Crp site 1, centered at -106, is essential for yiaK-S expression. The 5' end of the yiaJ gene was determined, and its promoter region was found to overlap with the divergent yiaK-S promoter. Expression of yiaJ is autogenously regulated and reduced by the binding of Crp-cAMP to the Crp site 1 of the yiaK-S promoter.

Amino Acid Sequence↗
PubMed1999

Effect of the alkyl chain length on the anaerobic biodegradability and toxicity of quaternary ammonium based surfactants.

The anaerobic biodegradability and toxicity to methanogenic gas production of different alkyl chain length homologs of quaternary ammonium based surfactants were examinated. Two series of these cationic surfactants were selected: alkyl trimethyl ammonium and alkyl benzyl dimethyl ammonium compounds. A simple anaerobic gas production test containing municipal digester solids as a source of anaerobic bacteria was used. Under the applied methanogenic conditions, the cationic surfactants tested showed a very poor primary biodegradation and no evidence of any extent of ultimate biodegradation was observed. The toxicity of quaternary ammonium based surfactants to methanogenic gas production decreased with increasing the alkyl chain length.

Alkylation↗
PubMed1999

Association between levels of fine particulate and emergency visits for pneumonia and other respiratory illnesses among children in Santiago, Chile.

Recent evidence has implicated the fine fraction of particulate as the major contributor to the increase in mortality and morbidity related to particulate ambient levels. We therefore evaluated the impact of daily variation of ambient PM2.5 and other pollutants on the number of daily respiratory-related emergency visits (REVs) to a large pediatric hospital of Santiago, Chile. The study was conducted from February 1995 to August 1996. Four monitoring stations from the network of Santiago provided air pollution data. The PM2.5 24-hr average ranged from 10 to 111 micrograms/m3 during September to April (warm months) and from 10 to 156 micrograms/m3 during May to August (cold months). Other contaminants (ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2)) were, in general, low during the study period. The increase in REVs was significantly related to PM10 and PM2.5 ambient levels, with the relationship between PM2.5 levels and the number of REVs the stronger. During the cold months, an increase of 45 micrograms/m3 in the PM2.5 24-hr average was related to a 2.7% increase in the number of REVs (95% CI, 1.1-4.4%) with a two-day lag, and to an increase of 6.7% (95% CI, 1.7-12.0%) in the number of visits for pneumonia with a three-day lag. SO2 and NO2 were also related to REVs. We conclude that urban air pollutant mixture, particularly fine particulates, adversely affect the respiratory health of children residing in Santiago.

Air Pollution↗
PubMed1999

Sources of Vibrio mimicus contamination of turtle eggs.

Vibrio mimicus contamination of sand increased significantly during the arrival of the olive ridley sea turtles (Lepidochelys olivacea) at Ostional anidation beach, Costa Rica. Statistical analysis supports that eggs are contaminated with V. mimicus by contact with the sand nest. V. mimicus was isolated from eggs of all nests tested, and ctxA+ strains were found in 31% of the nests, all of which were near the estuary.

Animals↗
PubMed1999

A comparative study of policosanol Versus acipimox in patients with type II hypercholesterolemia.

An 8-week, randomized, double-blind study comparing the efficacy and tolerability of policosanol and acipimox was conducted in patients with type II hypercholesterolemia. Prior to entry into active treatment, all patients followed a standard cholesterol-lowering diet for 12 weeks. Sixty-three patients were randomized to receive either policosanol (10 mg/day) or acipimox (750 mg/day) tablets for 8 weeks under double-blind conditions. Both groups were similar at randomization. Policosanol significantly reduced total cholesterol (p < 0.0001) (15.8%), low-density lipoprotein (LDL)-cholesterol (21%) and the ratios of LDL-cholesterol to high-density lipoprotein (HDL)-cholesterol (15.8%) and cholesterol to HDL-cholesterol (11.5%). Acipimox significantly lowered both cholesterol and LDL cholesterol by 7.5%. The percent changes of total cholesterol, LDL-cholesterol and both ratios were larger in the policosanol group than in the acipimox group. Both drugs were well tolerated. Acipimox significantly increased (p > 0.001) aspartate amino transferase levels but only four patients showed increases above the normal limit. Policosanol significantly reduced creatinine values (p > 0.05) but no patients had values out of the normal range. Four patients withdrew from the study (two from each group) but none withdrew because of adverse effects. No adverse effects were reported in the policosanol group, while five patients on acipimox reported adverse effects (hot flushes, nausea, vomiting, headache, hypochondrial pain and leg edema). These results indicate that policosanol (10 mg/day) was more effective and well tolerated than was acipimox (750 mg/day) in this study population.

Aged↗
PubMed1999

Immunocytochemical study of giant cell fibroma.

Giant cell fibroma (GCF) is a non-neoplastic lesion of the oral mucosa. The origin of stellate and multinucleate cells of GCF is not well known. The purpose of the present article was to investigate the immunoreactivity of these cells for leukocyte common antigen, vimentin, tryptase, HLA-DR, alpha-smooth muscle actin, CD68, and S-100. The results showed positive staining only for vimentin. This suggests that the stellate and multinucleate cells of GCF have a fibroblast phenotype.

Actins↗
PubMed1997

Protection against infection in mice vaccinated with a Brucella abortus mutant.

This study determines whether a genetically engineered mutant of Brucella abortus, strain M-1, possesses differences in protective properties compared to the parental strain, vaccine S19. M-1 is a mutant unable to express BP26, a periplasmic protein with potential use in diagnosis. Mice vaccinated with S19 developed antibodies against BP26, while those vaccinated with M-1 did not. However, mice vaccinated with S19 or M-1 were similarly protected against challenge with pathogenic strain 2308, suggesting that the lack of BP26 does not affect the induction of the protective immune response exerted by S19. These and previous results showing that bacterial invasion and growth or replication in mouse spleens were indistinguishable between strains M-1 and S19 could indicate that the mutant is an attenuated strain which maintains the same protective properties as S19.

Animals↗
PubMed1997

Human placental ecto-enzymes: studies on the plasma membrane anchorage and effect of inhibitors of ATP-metabolizing enzymes.

The human placental microvillar membrane contains several ectoenzymes, including 5'-nucleotidase, alkaline phosphatase and ATP-diphosphohydrolase (ATP-DPH), which might be involved in the extracellular metabolism of nucleotides. The type of anchorage to the plasma membrane of the two first enzymes has been shown to be via a glycosyl-phosphatidylinositol. In the present study, using an enzymatic approach, we show that the ATP-DPH should be attached to the plasma membrane through a different type of anchorage. We were also interested in the search of compounds which could interact differentially with this enzyme to be used as a tool for studying the other two hydrolytic enzymes in the presence of ATP-DPH. Here we report several inhibitors of ecto-ATPases which seem to be a useful tool for studying these three enzymes.

5'-Nucleotidase↗
PubMed1997

[Lipoprotein(a). Its importance as an additional atherosclerosis marker].

Lipoprotein(a) is one of the best examples of heterogeneity of lipoproteins. It presents pre-beta electrophoretic mobility in agarose gel, similar to Very Low Density Lipoproteins, it is found in High Density Lipoproteins due to its hydrated density greater than 1,063 and resembles Low Density Lipoproteins in its size and lipid composition. However, Lp(a) is unique in that it contains an additional distinct antigen, the apo(a), attached to apoB100 by one disulphide bridge. The apo(a)-glycoprotein has recently been shown to have a striking amino acid sequence homology with plasminogen; Lp(a) seems to be a potential bridge between atherosclerosis and thrombosis fields and interest in Lp(a) has greatly increased since then. The new knowledge on the structure of Lp(a) being more and more rapidly acquired should facilitate our understanding of the mechanisms of its atherogenicity and its physiopathological role. Metabolic studies have made it clear that Lp(a) is not a product derived from other apoB-containing lipoproteins, but is secreted by the liver as a distinct mature lipoprotein. Concerning the immunological techniques available to assay Lp(a) they need to be standardized and it is still necessary to define what is meant by the pathological threshold for Lp(a), which will certainly depend on the choice of the standard antiserum and immunological method used.

Apolipoproteins A↗
PubMed1996

Efficacy of transfer factor in treating patients with recurrent ocular herpes infections.

Recurrent ocular herpes is an insoluble problem for the clinician. As cellular immunity plays an important role in controlling herpes relapses, and other studies have shown the efficacy of HSV-specific transfer factor (TF) for the treatment of herpes patients, an open clinical trial was undertaken in 134 patients (71 keratitis, 29 kerato-uveitis, 34 uveitis) suffering from recurrent ocular herpetic infections. The mean duration of the treatment was 358 days, and the entire follow-up period 189,121 before, and 64,062 days after TF treatment. The cell-mediated immune response to the viral antigens, evaluated by the lymphocyte stimulation test (LST) and the leucocyte migration test (LMT) (P < 0.001), was significantly increased by the TF treatment. The total number of relapses was decreased significantly during/after TF treatment, dropping from 832 before, to 89 after treatment, whereas the cumulative relapse index (RI) dropped, during the same period, from 13.2 to 4.17 (P < 0.0001). No side effects were observed. It is concluded that patients with relapsing ocular herpes can benefit from treatment with HSV-specific TF.

Adolescent↗
PubMed1996

Vibrio mimicus diarrhea following ingestion of raw turtle eggs.

Clinical and epidemiological characteristics of diarrhea associated with Vibrio mimicus were identified in 33 hospitalized patients referred to the Costa Rican National Diagnostic Laboratory Network between 1991 and 1994. The relevant symptoms presented by patients included abundant watery diarrhea, vomiting, and severe dehydration that required intravenous Dhaka solution in 83% of patients but not fever. Seroconversion against V. mimicus was demonstrated in four patients, from whom acute- and convalescent-phase sera were obtained. Those sera did not show cross-reaction when tested against Vibrio cholerae O1 strain VC-12. All the V. mimicus isolates from these cases produced cholera toxin (CT) and were susceptible to commonly used antibiotics. Attempts to isolate this bacterium from stool samples of 127 healthy persons were not successful. Consumption of raw turtle eggs was recalled by 11 of the 19 (58%) individuals interviewed. All but two V. mimicus diarrheal cases were sporadic. These two had a history of a common source of turtle (Lepidochelys olivacea) eggs for consumption, and V. mimicus was isolated from eggs from the same source (a local market). Among the strains, variations in the antimicrobial susceptibility pattern were observed. None of the strains recovered from market turtle eggs nor the four isolates from river water showed CT production. Further efforts to demonstrate the presence of CT-producing V. mimicus strains in turtle eggs were made. Successful results were obtained when nest eggs were tested. In this case, it was possible to isolate CT- and non-CT-producing strains, even from the same egg. For CT detection we used PCR, enzyme-linked immunosorbent assay (ELISA), and Y-1 cell assay, obtaining a 100% correlation between ELISA and PCR results. Primers Col-1 and Col-2, originally described as specific for the V. cholerae O1 ctxA gene, also amplified a 302-bp segment with an identical restriction map from V. mimicus. These results have important implications for epidemiological surveillance in tropical countries where turtle eggs are used for human consumption, serving as potential sources of cholera-like diarrhea.

Adult↗
PubMed1996

Isolation and characterization of two distinct species of human very low density lipoproteins lacking apolipoprotein E.

We have isolated two fractions of very low density lipoprotein particles in human plasma that lack apolipoprotein (apo) E by combined anti-apoE and heparin affinity chromatography of whole plasma followed by ultracentrifugation. The two fractions are distinguished by their ability to bind to heparin. Each of these fractions, designated "B" particles to distinguish them from very low density lipoproteins that contain apoE ("B,E" particles), comprises an appreciable fraction of total particles in very low density lipoproteins of normolipidemic and hypertriglyceridemic subjects. The heparin-unbound B particles, which have been reported previously by others, are larger and have negligible affinity for low density lipoprotein receptors. The heparin-bound B particles are smaller and do bind to low density lipoprotein receptors, albeit with much lower affinity than B,E particles. No differences in accessibility to limited protease digestion were found between apoB-100 in the two types of B particles. Our data indicate that a substantial fraction of human very low density lipoproteins lacks apoE, the principal ligand for lipoprotein receptors that mediate the terminal catabolism of these lipoproteins. Whereas the B particles that fail to bind to heparin are likely to represent a form of nascent lipoprotein, the origin of those B particles that bind to heparin remains to be determined.

Adult↗
PubMed1995

Micronuclei induction by carboplatin in human lymphocyte subpopulations.

Micronuclei (MN) induction by carboplatin, cis-diammine-1,1-cyclobutane decarboxylate platinum (II) (CBDCA), in B and T lymphocytes was studied by the MAC (morphology/antibody/chromosome) method which allows the immunologic identification of different cell lineages. An increased frequency of MN in B and T lymphocytes in CBDCA-treated cultures compared with controls was observed (p < 0.001). CBD cells were found to be more sensitive to CBDCA damage. CBDCA-treated cultures showed a decrease, albeit statistically non-significant, in the proportion of CBD interphasic and mitotic cells. Furthermore, higher MN frequencies in isolated lymphocytes than in whole blood in both control and CBDCA-treated cultures were observed.

Adult↗