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Biomedical subjects

C Trejo

Publications and source records attributed to C Trejo.

11 recordsLinked to original sources
PubMed2001

Is the capacity of lead acetate and cadmium chloride to induce genotoxic damage due to direct DNA-metal interaction?

Even though the toxic effects of lead and cadmium compounds have been studied over many years, inconsistent results have been obtained about their mutagenic, clastogenic and carcinogenic properties. However, these metals are considered to be potential human carcinogens. The mechanism of metal-induced carcinogenesis is still unknown, but one possible pathway may involve the interaction of metals with DNA, either directly or indirectly. In this work we explore the capacity of lead, cadmium or a mixture of both metals to interact with acellular DNA, by employing a variant of the comet assay. Our results, using low non-cytotoxic metal concentrations (0.01, 0.1 and 1.0 microM) with the standard protocol for the acellular assay, showed an induction of DNA damage in cells of all organs studied; however, basal DNA damage was different in each organ. To confirm that we were working with pure DNA, proteinase K was added to the lysis solution. With this enriched-lysis solution we found a negative response in the induction of DNA damage in cells derived from the liver, kidney and lung of CD-1 male mice. To support the results obtained by the enriched-acellular assay, we studied the capacity of lead and cadmium (0.1 microM) to induce breaks in pooled genomic DNA in cells of the same organs, with negative results. Consistent with these findings, these metals do not induce DNA breaks in the plasmid pUSE amp+. On the whole, we did not detect direct induction of DNA strand breaks by lead acetate, cadmium chloride or a mixture of both metals, all at low non-cytotoxic concentrations. However, we found an induction of lipid peroxidation and an increase in free radical levels in the different organs of CD-1 male mice after inhalation of lead acetate (0.0068 microg/cc) or cadmium chloride (0.08 microg/cc) for 1 h, suggesting the induction of genotoxicity and carcinogenicity by indirect interactions, such as oxidative stress.

Animals↗
PubMed2001

Prevalence and isotype distribution of antiphospholipid antibodies in Chilean patients with systemic lupus erythematosus (SLE).

Previous studies have demonstrated that ethnicity plays a role in the prevalence, isotype distribution, and clinical significance of anticardiolipin (aCL) and anti-beta2 glycoprotein I (abeta2-GPI) antibodies in systemic lupus erythematosus (SLE) patients. Few studies have been done in Latin American populations. Serum samples from 129 Chilean SLE patients were tested for IgG, IgM and IgA aCL and abeta2-GPI by ELISA. Clinical data were reviewed with the focus on clinical manifestations of antiphospholipid syndrome (APS). Positivity for at least one isotype of aCL was found in 30% of patients, while only 10% were positive for at least one isotype of abeta2-GPI. IgG was the most prevalent isotype for aCL (16%), and the isotype distribution was similar (4%) for abeta2-GPI. In general, the presence of aCL was significantly associated with the presence of abeta2-GPI, but a number of samples were positive for only one antibody, some of them associated with clinical manifestations of APS. ACL antibodies at medium-high titers were significantly correlated with thrombosis (P = 0.0007) and fetal loss (P = 0.009); however, the sensitivity of abeta2-GPI for detecting thrombosis and fetal loss was lower than aCL (19 and 17% vs 56 and 50%, respectively), and the specificity slightly higher (91 and 90% vs 84 and 82%). In Chilean SLE patients, aCL and abeta2-GPI antibodies are important in the evaluation of patients with APS. However, the utility of abeta2-GPI antibodies was limited by the low prevalence of these antibodies in comparison with other ethnic groups. Further studies are needed to define the basis of the observed differences among ethnic groups.

Antibodies, Antiphospholipid↗
PubMed2000

The role of abscisic acid in controlling leaf water loss, survival and growth of micropropagated Tagetes erecta plants when transferred directly to the field.

Plants of Tagetes erecta L. (marigold) cultivated in vitro in ventilated containers exhibited greater control of leaf water loss and increased survival in the field than plants cultivated in sealed containers. Increased field survival of plants cultivated in ventilated containers was attributed to higher levels of endogenous abscisic acid (ABA). Therefore, ABA was supplied exogenously to plants in sealed or ventilated containers by adding ABA (10(-6), 10(-5), 10(-4) M) to the in vitro culture media in order to evaluate control of leaf water loss, growth and field survival. The addition of 10(-4) M ABA to the culture media in sealed containers produced plants that had similar control of leaf water loss and were morphologically similar to plants cultivated in ventilated containers without the addition of ABA. Field survival of 10(-4) M ABA plants (75%) was increased compared to plants cultivated in sealed containers without ABA (31%), with survival being closer to that of plants cultivated in ventilated containers (90-100%). Plants cultivated with 10(-4) M ABA (sealed and ventilated) also exhibited increased plant vigour and leaf area in the field compared to plants cultivated without ABA. The results suggest that the limited field survival and growth of plants cultured in vitro are related to the limited ABA concentrations they accumulate while in vitro. Consequently, conditions that increase the endogenous ABA concentrations of in vitro plants (like ventilation or ABA addition to the medium) would improve the control of leaf water loss, field survival and plant vigour.

Abscisic Acid↗
PubMed2000

[Human rights and their relationship with patient's rights].

This historical article reviews the most important milestones in the evolution of human and patient's rights. The latter have derived from human rights and have followed a similar historical evolution, but in markedly different times. This has lead to the persistence of monarchic type, paternalistic clinical relationship forms in republican societies. The acceptance of informed consent and patient's rights has been a democratization of clinical relationships. On the other hand the right to body health management is a real cultural revolution. The democratization of clinical relationship is in agreement with our technical, pluralist and secularized times.

Bioethics↗
PubMed1992

[Tuberculosis of the pancreas, an anatomoclinical case].

A 49 year old "mapuche" male patient was operated on and tuberculosis of the gallbladder was found. Later on, he developed evidence of meningeal and pulmonary involvement and elevated pancreatic enzyme levels. In spite of appropriate anti-tuberculosis therapy, the patient died. Autopsy revealed multiorgan involvement with pancreatic tuberculosis and areas of steatonecrosis. Immune deficiency related to the previous cholecystectomy may have facilitated the severe dissemination of the disease observed in this patient.

Humans↗
PubMed1991

[Ecologic ethics: a response for our times].

To understand the ethics of our present time (macrocosmos), the patient-physician relationship (microcosmos complex) and its changes through history are analyzed. The patient-physician relationship is no longer between two individuals, it is plural and technified. An individualistic forms of ethic cannot answer the questions that arise from contemporary society. The power (political) of medical science has placed us at the threshold of a qualitative change, new that the human genome can be known and the very nature of the species can be modified. Man's destiny will depend on the way (ethic) he uses his knowledge. An ecological ethic could be the answer.

Ecology↗
PubMedDate not supplied

[The usefulness of endoscopic polypectomy of rectosigmoid and colon in childhood].

Rectal polyps are relatively frequent in infancy and constitute one of the main causes of hematoquezia during this time of life. They are usually treated with multiple drugs before the correct diagnosis is made. We report our experiences with the use of rectoscopy and colonoscopy for the diagnosis and treatment of 214 patients with rectosigmoid polyps, including other sites in the colon, studied between 1982-1988. The highest incidence was between 3 and 6 years of age (63.8%), and the most frequent location in 253 rectosigmoid polyps (91%) and histologically (99.7%) were juvenile polyps. Endoscopic polypectomy proved to be a valuable method, easy to perform and with few complications to treat colon polyps, thus eliminating the surgical interventions.

Child↗
PubMedDate not supplied

[Predictive value of ultrasonography in portal hypertension].

Portal hypertension is a common pathology in childhood and one of its most common causes is cavernomatosis of the portal vein. This obstruction causes hemodynamic changes which lead to splenomegaly and collateral circulation. Esophageal varices are one of the most important sequelae, which endanger the patient's life because of a bleeding tendency. Ecosonography helps to detect the thickening of the lesser omentum vis a vis the aortic diameter, caused by the collateral circulation. We studied 15 children presenting with portal hypertension resulting from portal vein cavernomatosis; we performed an upper GI endoscopy and abdominal ecosonography. The endoscopy revealed grade II esophageal varices in 20% of cases, the remaining 80% had grade III and grade IV. Ecosonography revealed an increased lesser omentum/aorta ratio in children with portal hypertension, compared to controls (p < 0.001). Our results suggest that the lesser omentum/aorta ratio has diagnostic value in pediatric portal hypertension.

Aorta, Abdominal↗
PubMedDate not supplied

[Biliary ascaridiasis in children. Ultrasonic diagnosis].

Ascariasis is one of the most frequent intestinal parasitosis of man, specially in tropical regions where it affects mostly children. The adult worm can migrate through the ampulla of vater and penetrate the bile ducts producing different degrees of obstruction and infection. Ultrasonography is a rapid and simple non invasive procedure very effective for the visualization of the worm in the biliary tree. We present the clinical and ultrasonographic characteristic of biliary ascariasis in five children diagnosed by ultrasonography in our institution during the last nine years.

Animals↗
PubMedDate not supplied

[Usefulness of colonoscopy in the diagnosis of colonic diseases in childhood].

We present here our experience in colonoscopy performed in 93 children between 1984-1988 at hospital J. M. de los Ríos de Caracas. Mean age was 5.44 y/o and the range was 2-13 y/o. Rectal bleeding in 91.36% of the cases was the most common indication of the procedure. Rectal and sigmoid polyps were found in 24.73%. Vascular malformations in 16.13%, studies informs as normal 13.98% and ulcerative colitis in 10.75% No complications were observed so we can suggest colonoscopy as the first tool in diagnosis and treatment of the colonic pathology in children of any age.

Adolescent↗