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Biomedical subjects

S Contreras

Publications and source records attributed to S Contreras.

At least 19 recordsLinked to original sources
PubMed2006

Computed tomographic anatomy of the head of the loggerhead sea turtle (Caretta caretta).

The heads of three loggerhead sea turtles were disarticulated and imaged immediately to minimize postmortem changes and then frozen and sectioned. For computed tomography (CT) imaging, the heads were positioned in ventral recumbency. Transverse CT images with soft-tissue window were obtained from the olfactory sac region to the temporomandibular joint region. After CT imaging, the heads were sectioned and the gross sections were compared to CT images, to assist in the accurate identification of the anatomic structures. Different clinically relevant anatomic structures were identified and labelled in two series of photographs (CT images and anatomic cross-sections). CT images provided good differentiation between the bones and the soft tissues of the head. The information presented in this paper should serve as an initial reference to evaluate CT images of the head of the loggerhead sea turtle and to assist in the interpretation of lesions of this region.

Animals↗
PubMed2006

Study of KIR genes in tuberculosis patients.

A total of 97 patients with tuberculosis (TB) and 51 controls from Xalapa, Veracruz, Mexico, were studied for the presence and absence of killer cell immunoglobulin-like receptor (KIR) genes. The number of patients with either KIR2DL1 or KIR2DL3 differed significantly compared with the controls. However, only the difference in KIR2DL3 remained significant after correction for the number of factors analysed. We also found KIR2DS2 with its presumed C1 group ligand less prevalent in TB patients than in the control group, but this result lost significance after correction.

Adult↗
PubMed2006

Association analyses of the neuregulin 1 gene with schizophrenia and manic psychosis in a Hispanic population.

OBJECTIVE: This study used the population of the Central Valley of Costa Rica (CVCR) and phenotyping strategies alternative to DSMIV classifications to investigate the association of neuregulin 1 with schizophrenia. METHOD: Using 134 family trios with a history of psychosis, we genotyped six of the seven markers originally identified to be associated with schizophrenia in Iceland. RESULTS: The neuregulin Icelandic haplotype was not associated with schizophrenia in the CVCR population. However, a novel haplotype was found to be overrepresented in subjects with functional psychosis (global P-value > 0.05). Stratification of the sample by history of mania suggests that this haplotype may be preferentially over-transmitted to persons with a history of manic psychosis. CONCLUSION: These results suggest that the neuregulin 1 gene is unlikely to play a major role in predisposing to schizophrenia in the CVCR. Further studies in the CVCR and other Latin American populations should be performed in order to corroborate these findings.

Bipolar Disorder↗
PubMed2006

Degradation of 2,4-dichlorophenol by combining photo-assisted Fenton reaction and biological treatment.

The photo-Fenton reaction effect on the biodegradability improvement of 100 mg/L solution of 2,4-dichlorophenol (DCP) has been investigated. Biochemical oxygen demand (BOD) at 5 and 21 days, BODn/ chemical oxygen demand (COD) and BODn/total organic carbon (TOC) ratios, average oxidation state, and inhibition on activated sludge were monitored. For 50 mg/L hydrogen peroxide and 10 mg/L iron(II) initial concentrations and 40 minutes of reaction time in the photo-Fenton process, the biodegradability of the pretreated solution, measured as BOD5/COD ratio, was improved from 0 for the original DCP solution up to 0.18 (BOD21/COD = 0.24). At that point, all DCP was eliminated from the solution. To study the effect of the pretreatment step, the biological oxidation of pretreated solutions was tested in two semicontinuous stirred tank reactors, one operated with activated sludge and one with biomass acclimated to phenol. Results showed that more than 80% TOC removal could be obtained by codigestion of the pretreated solution with municipal wastewater. Total organic carbon removals of approximately 60% were also obtained when the sole carbon source for the aerobic reactors was the pretreated solution. The hydraulic retention times used in the bioreactors were of the same order of magnitude as those used at domestic wastewater treatment plants (i.e., between 12 and 24 hours). Kinetic studies based on pseudo-first-order kinetics have also been carried out. Constants were found to be in range 0.67 to 1.7 L x g total volatiles suspended solids(-1) x h(-1).

Biodegradation, Environmental↗
PubMed2005

Effect of ME-3451-106, an aqueous extract of Stichaster striatus with inhibitory activity of voluntary alcohol intake, in genetically drinker rats: Isolation and identification of the active fraction.

The aqueous extract obtained from Stichaster striatus Müller & Troschel (Asteroidea, Stichasteridae) has been shown to possess activity as an alcohol appetite inhibitor after oral administration in a rat model with a genetically established excessive appetite for alcohol (Wistar rats, lineage UChB). A significant decrease in the consumption of ethanol was observed (unrelated to a possible disulfiram effect) without a change in the normal food or water intake during the experimentation period. A bio-guided fractionation of the extract was carried out in order to identify the most active fraction, in which the presence of a group of natural endogenous polyamines in undetermined proportions is suspected. Our hypothesis was to relate the activity obtained for the original ME-3451-106 extract with the presence of these polyamines in the extract in question. The activity shown by a series of commercially available polyamines (putrescine (Pu), spermidine (SPD) and spermine (SP)) in inhibiting voluntary ethanol intake lends support to our hypothesis. The extract was selected on the basis of oral tradition, which claimed that the consumption of a "soup" obtained by boiling starfish, later identified as Stichaster striatus, prevented the appearance of alcoholism in laborers on properties entrusted to the Jesuit order during the middle period of the Spanish conquest of America (17-18th century).

Alcohol Deterrents↗
PubMed2003

Contribution of the ozonation pre-treatment to the biodegradation of aqueous solutions of 2,4-dichlorophenol.

The effect of ozonation on the biodegradability of 100-ppm aqueous solutions of 2,4-dichlorophenol has been investigated. BOD at 5, 10 and 21 days, BOD/COD and BOD/TOC ratios and the average oxidation state are presented. Biodegradability measured as BOD5/COD ratio was increased from 0 of the original solution to 0.25 at the moment of removing all the initial compound (corresponding to an ozone dose of 0.12 g L-1, 0.48 for BOD21/COD ratio). To test the effect of this pre-treatment, the biological oxidation of these pre-ozonated solutions was performed in two semi-continuous stirred tank reactors, one with non-acclimated sludge and one with acclimated-to-phenol sludge. The study showed that the TOC content of the pre-treated solution could be removed up to 68% by an aerobic biological treatment as well as co-digested with municipal wastewater (TOC removal up to 82%), with similar operating retention times to a municipal wastewater plant (12-24 h). Kinetic studies based on Monod model have also been carried out. Pseudo-first-order kinetic constants were found to be in the range of 0.5-0.8 L g TVSS-1 h-1.

Anthelmintics↗
PubMed2001

Anti-depressant prescribing patterns for prison inmates with depressive disorders.

BACKGROUND: Although prison inmates are reported to exhibit elevated rates of depressive disorders, little is known about anti-depressant prescribing patterns in correctional institutions. METHODS: The study population consisted of 5305 Texas Department of Criminal Justice (TDCJ) inmates who were diagnosed with one of three depressive disorders: major depression, dysthymia, and bipolar disorder (excluding those with manic episodes only). Information on medical conditions, sociodemographic factors, and pharmacotherapy was obtained from an institution-wide medical information system. RESULTS: In 1998, 78.2% of all inmates diagnosed with depressive disorders were treated with antidepressant medication. Of these, 47.3% were treated exclusively with tricyclic anti-depressants (TCA); 30.9% were treated with selective serotonin re-uptake inhibitors (SSRI); and 21.8% were not treated with any form of anti-depressant medication. Prescribing patterns varied substantially according to a number of sociodemographic factors under study. LIMITATIONS: Because the present study relied on retrospective, clinical data, the investigators had limited ability to assess: specific symptomatology for each diagnosed depressive condition under study; socio-economic status, pre-incarceration access to health care; and the overall reliability and validity of the data. CONCLUSION: The proportion of prison inmates with depressive disorders who receive appropriate medication management is substantially higher than that reported among similarly diagnosed nonincarcerated samples. It will be important, however, for future investigators to examine the sources of sociodemographic variation in treatment patterns found in the present study.

Adult↗
PubMed2001

Oxidation of nitrobenzene by O3/UV: the influence of H2O2 and Fe(ll). Experiences in a pilot plant.

Abstract The degradation of nitrobenzene using some advanced oxidation processes (O3/UV, O3/UV/H2O2 and O3/UV/Fe(III)) has been investigated. In the combined O3/UV process, the effect of pH and ozone was studied. In the other combinations, the influence of the amount of hydrogen peroxide and ferric ion in the degradation rate and TOC evolution, has been studied. Under our conditions, the combination O3/UV did not improve the degradation rate obtained by ozonation. The best TOC decrease was obtained when the O3/UV process was carried out at low ferric ion concentrations.

Ferric Compounds↗
PubMed2000

Compliance with antidepressant medication among prison inmates with depressive disorders.

This study assessed correlates of antidepressant medication compliance among 5,305 inmates of the Texas Department of Criminal Justice prison system who were diagnosed as having a depressive disorder. Use of tricyclic antidepressants, male gender, and higher age were all positively associated with medication compliance scores. This investigation provided no evidence that broader use of selective serotonin reuptake inhibitors would improve adherence to pharmacologic treatment in this population. The results also suggest that correctional administrators may wish to target younger inmates and women with interventions to improve medication compliance.

Adolescent↗
PubMed1995

Two different cis-acting regulatory regions direct cell-specific transcription of the collagen alpha 1(I) gene in hepatic stellate cells and in skin and tendon fibroblasts.

The expression of the collagen alpha 1(I) gene in activated stellate cells plays an important role during liver fibrogenesis. To identify the critical cis-elements of the collagen alpha 1(I) gene in stellate cells, we used transgenic animals bearing various collagen alpha 1(I) regulatory regions directing the expression of either a human growth hormone minigene or the bacterial beta-galactosidase gene. We found that collagen alpha 1(I)-human growth hormone transgene expression was constitutively high in tendon and skin, provided the transgene contained the -2.3 to -0.44 kb collagen regulatory region. However in the liver, expression was stimulated several-fold, as was the endogeneous gene, by the fibrogenic hepatotoxin carbon tetrachloride. This stimulation occurred whether the collagen 5' regulatory region extended -2.3, -1.6 or -0.44 kb, and in the presence or absence of much of the first intron (+292 to +1607 bp). In addition, the -0.44 kb 5' region was sufficient for high-level transgene expression in stellate cells, following their activation by culture on plastic. In contrast, in skin and tendon, high-level transcription of the collagen alpha 1(I) gene required the -2.3 to -0.44 kb 5' flanking region. Thus, two different cis-regulatory regions direct cell-specific transcription of the collagen alpha 1(I) gene in stellate cells and in skin and tendon.

Animals↗
PubMed1993

Acute effects of neuroleptics on unmedicated schizophrenic patients and controls.

Acute administration of haloperidol (0.2 mg/kg) produced many more side effects in normal controls than in unmedicated schizophrenic patients. Prior to the neuroleptic challenge, both groups were on the peripheral monoamine oxidase inhibitor, debrisoquin, for at least 1 week, in order to enhance the relative contribution of CNS catecholamine metabolites to those measured in both plasma and urine. The patient group had higher plasma levels of methoxyhydroxyphenylglycol (MHPG) and homovanillic acid (HVA) and higher urinary MHPG output than controls, but there were no effects of haloperidol challenge, compared to placebo challenge. In both groups there were significant declines in plasma HVA levels from 8:30 AM to 12 NOON. These declines were unaffected by the haloperidol challenge. Explanations for the marked differences in behavioral effects of haloperidol on patients and controls include the possibility that dopamine receptor numbers were increased in the brains of the schizophrenic patients.

Adult↗
PubMed1990

Neurobiology of schizophrenic syndromes.

The development of imaging technologies for investigating the living human brain has expanded knowledge about schizophrenia and is providing clues about biological factors associated with the disorder. Drawing on these and other developments in the last two decades, the authors review selected structural, functional, neurochemical, immunological, and infectious factors associated with the schizophrenic syndrome. Many of the biological alterations reported have also been found in other psychiatric, neurological, and medical conditions; therefore, the findings have little specificity for schizophrenia and in fact support the heterogeneity of the disorder.

Brain↗
PubMed1990

[The pharmacokinetic bases of management with drugs having a narrow therapeutic range].

The growing tendency to measure blood drug levels of patients with different diseases call for understanding of pharmacokinetic basis of this diagnostic tool. The article is focused on the pharmacological basis of drug use, as well as on factors involved in pharmacokinetic variations related to clinical picture and biological condition of the patient. Processes regulating drug entry and drug release to and from the general circulation are discussed in the context of disease pathophysiology.

Absorption↗
PubMed1988

Calcium function in affective disorders and healthy controls.

Calcium metabolism has been reported to be disturbed in some forms of affective disorder. We studied concurrently a battery of calcium measures in 29 unipolar, 14 bipolar depressed, 11 manic, and 10 healthy control subjects. In addition to measures of extracellular calcium, we studied intracellular calcium concentration in platelets and measures that reflect cellular capability to maintain a low intracellular Ca++ concentration in red blood cells (RBCs) and platelets. Plasma calcium was lower in unipolar and manic patients than in control subjects. Platelet calcium concentration was lower in unipolar than bipolar depressed patients. RBC Ca++ adenosine triphosphatase (ATPase) was lower in unipolar and control subjects than in bipolar depressed and manic patients. Platelet Ca++ ATPase and Ca++ uptake were inversely correlated with severity of illness in unipolar patients. In bipolar depressed patients, RBC Ca++ ATPase and platelet Ca++ uptake were inversely correlated with severity. In addition to indicating abnormalities in calcium activity in affective disorders, the data suggest that unipolar and bipolar patients differ in several measures and may have different pathophysiological disturbances in calcium metabolism.

Adult↗
PubMed1988

Growth of rat osteoblast-like cells in a lipid-enriched culture medium and regulation of function by parathyroid hormone and 1,25-dihydroxyvitamin D.

To examine the role of lipid metabolism in the growth and function of osteoblast-like cells, we studied ROS 17/2.8 osteosarcoma cells and primary cultures of rat calvarial osteoblasts during growth in a serum-free medium supplemented by purified human lipoproteins or by liposomes. Increase in ROS cell number was measured in sparse (1-5 X 10(3)/cm2) cultures over 6-8 days. Liposomes (0-300 micrograms/ml) and high (HDL), low (LDL), and very low density (VLDL) lipoprotein fractions (0-300 micrograms apoprotein) markedly stimulated cell growth. Cells plated at 5 X 10(3)/cm2 achieved growth rates in the presence of LDL or HDL comparable to 10% fetal bovine serum. Serum-free culture with exogenous lipid maintained the response of cell cyclic AMP accumulation to parathyroid hormone. Cyclic AMP response to parathyroid hormone was enhanced by glucocorticosteroid, and was attenuated by 1,25-dihydroxyvitamin D (1,25(OH)2D) with an EC50 (10(-10) M) comparable to that previously observed in serum-cultured cells (J. Biol. Chem. 258:736, 1985). 1,25(OH)2D also increased the alkaline phosphatase activity in ROS cells cultured in lipid-supplemented serum-free culture. Lipoproteins or liposomes also markedly enhanced the proliferative response of sparse cultures of normal rat osteoblasts to polypeptide mitogens.

Animals↗
PubMed1987

Effects of alpha-methylparatyrosine on voluntary consumption of ethanol, water, and solid food in UChA and UChB rats.

The effect of daily doses of 80 mg/kg (intraperitoneal) of alpha-methylparatyrosine, AMPT (inhibitor of tyrosine hydroxylase) on the voluntary consumption of ethanol, water, and solid food was studied in rats of both sexes belonging to the UChA (lower ethanol consumer) and UChB (high ethanol consumer) strains. The consumptions during the treatment period were compared to those of the preceding one (basic). Decrease of ethanol and solid food intake and increase of that of water in UChB rats and only a decrease of solid food intake in UChA rats were observed. These effects cannot be ascribed to blocking of dopaminergic or noradrenergic synapses, since this dose of AMPT inhibits the in vivo synthesis of both catecholamines.

Alcohol Drinking↗