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Biomedical subjects

R Torres

Publications and source records attributed to R Torres.

At least 73 records · Page 4Linked to original sources
PubMed1998

Biosorption of nickel using filamentous fungi.

Nickel (Ni) uptake capability from aqueous solutions was studied in a filamentous fungi strains group of Rhizopus sp., Penicillium sp. Aspergillus sp., Trichoderma sp., Byschoclamyss sp., and Mucor sp. The metal uptake of a Rhizopus sp. strain, which has the highest uptake capacity, was corroborated by electron microscopy; no Ni deposits were observed on the cell wall, but rather a homogeneous accumulation was seen on the cell surface. The influence on the capacity of metal uptake by environmental parameters such as pH, temperature, time, and the interference of other ions in the solution, was also studied. Nickel accumulation by the selected strains is fast, occurring in less than 30 min, and does not require a microorganism's active metabolism to take place. The sorption isotherms were established for the selected fungi, in order to determine the maximum metal uptake capacity. The sorption isotherms were fixed to the mathematical models of Freundlich and Langmuir, obtaining better performance on the Langmuir model.

Aspergillus↗
PubMed1998

Bowel management for fecal incontinence in patients with anorectal malformations.

BACKGROUND/PURPOSE: Fecal incontinence is common in patients operated on for anorectal malformations. Treatment with enemas, laxatives, and medications are often given by clinicians in an indiscriminate manner and without a demonstrated benefit. A systematic diagnostic approach and bowel management program was developed for patients suffering from fecal incontinence, and a retrospective analysis of the results is presented. METHODS: Three hundred forty-eight patients were seen in consultation for fecal incontinence after repair of imperforate anus at other institutions. Clinical and radiological evaluation helped determine different types of patients. Group I consisted of 147 patients who were considered candidates for reoperation and forms the basis of a future report. Group II included 172 patients who had no potential for bowel control and were therefore candidates for bowel management. These patients fell into two categories; group IIA included 44 patients with incontinence and constipation. The bowel management involved the use of daily large enemas only. Group IIB included 128 patients with incontinence and a tendency to diarrhea. Group III consisted of 29 patients who had pseudoincontinence. They had an original defect with good prognosis, good sphincters, good sacrum, and a well-located rectum. They suffered from severe constipation, megasigmoid, chronic fecal impaction, and overflow pseudoincontinence and were treated with laxatives or sigmoid resection. RESULTS: Bowel management was successful in 93% of patients in the constipation group (IIA) and 88% in the diarrhea group (IIB). Ninety-seven percent of patients in group III became fecally continent. CONCLUSION: Bowel management consisting of enemas, laxatives, and medications is successful when administered in an organized manner. It is vital to determine the type of fecal incontinence from which the patients suffer and to target their treatment accordingly.

Anus, Imperforate↗
PubMed1998

Anorectal malformations and Down's syndrome.

BACKGROUND/PURPOSE: Down's syndrome is a common association in patients with anorectal malformations. The purpose of this study was to determine whether the anorectal defect in patients with Down's syndrome had specific characteristics and whether the presence of Down's syndrome represented a serious detriment to the patient's functional prognosis. METHODS: Nine hundred eighty-seven patients with anorectal malformations were studied retrospectively. Twenty patients (2%) had Down's syndrome. Nineteen of these (95%) had the same specific type of anorectal defect: imperforate anus with no fistula. This defect has a good prognosis, the rectum is located about 2 cm above the perineal skin, the sacrum is normal, and the sphincter mechanism is good. For comparison, a group of 34 patients with the same defect but without Down's syndrome was also studied. All patients were operated on via posterior sagittal approach by the same surgeon. RESULTS: Imperforate anus without fistula occurs in 5% of all patients with anorectal malformations and in 95% of those patients who also suffer from Down's syndrome. The characteristics of the defect were the same in both groups of patients, and surprisingly, the prognosis was good in both groups (80% to 96% of patients had voluntary bowel movement, 100% had urinary continence). CONCLUSIONS: The association of Down's syndrome with imperforate anus without fistula is not coincidental. This particular benign defect can be predicted to occur in most patients with Down's syndrome. The presence of Down's syndrome in cases of anorectal malformations should not be a contraindication to repairing the imperforate anus and to closing the colostomy.

Anus, Imperforate↗
PubMed1998

Predisposition of Wolfram syndrome heterozygotes to psychiatric illness.

Identification of specific genes that predispose to psychiatric illness will lead to more precise psychiatric diagnosis and more effective treatment. Heterozygous carriers of genes for many autosomal recessive syndromes may be 1% or more of the general population. Thus, if mutations at a specific locus produce psychiatric manifestations in homozygous affected individuals, it is important to determine whether mutations at such a locus also predispose heterozygous carriers to psychiatric disorders. The hypothesis that heterozygous carriers of the gene for the Wolfram syndrome (WS) are predisposed to psychiatric illness was supported previously by the finding of an excess of psychiatric hospitalizations and suicides in WS blood relatives compared to spouse controls. This hypothesis has now been tested further by comparing the number of psychiatrically hospitalized blood relatives with the specific marker haplotype associated with the Wolfram syndrome gene in their families to the number expected under the null hypothesis, calculated from Mendelian inheritance principles and the estimated haplotype frequency. The proportion of psychiatrically hospitalized relatives who were WS carriers (10/11) was much higher than expected (3.1/11), leading to the provisional estimate that WS gene carriers are 26-fold more likely to require psychiatric hospitalization than non-carriers.

Adult↗
PubMed1997

Evaluation of the wound-healing activity of selected traditional medicinal plants from Perú.

Folk medicine practitioners in Perú employ plant preparations as wound-healing agents on superficial and internal wounds (gastric ulcers). The results of a scientific evaluation of the wound-healing activity of nine plants found in the Amazon jungle near Iquitos and in the Andes mountains is presented. The species studied were: Peperomia galioides, Mentzelia cordifolia, Mutisia acuminata, Himatanthus sucuuba, Spondias mombin, Eleutherine bulbosa, Muehlenbeckia tamnifolia, Anredera diffusa and Jatropha curcas. These plants have also been examined for their toxicological properties, their effect on blood pressure, smooth muscle and capillary permeability. Significant wound-healing activity was detected in Peperomia galioides, Anredera diffusa and Jatropha curcas. Extracts from Peperomia galioides and Anredera diffusa had no effect on cell proliferation and did not exhibit mutagenic activity.

Animals↗
PubMed1997

C2H2-171: a novel human cDNA representing a developmentally regulated POZ domain/zinc finger protein preferentially expressed in brain.

We describe a novel human zinc finger cNDA. C2H2-171. This cDNA represents an mRNA which encodes a protein of 484 amino acids and a calculated molecular weight of 54 kD. Four zinc finger-like domains are found in the C-terminal end of the protein. At the N-terminus, C2H2-171 contains a POZ/tramtrack-like domain similar to that found in the tumor associated zinc finger proteins LAZ-3/BCL-6 and PLZ-F, as well as in non-zinc finger proteins. C2H2-171 RNA is preferentially expressed in the brain, and increases during the course of murine development, with maximal expression in the adult. C2H2-171 RNA is differentially expressed in brain regions, with the highest level of expression in the cerebellum. C2H2-171 RNA was expressed at high levels in primary cerebellar granule cell neurons compared to astrocytes. The gene encoding C2H2-171 is highly conserved in vertebrates, and maps to the terminus of human chromosome 1 (1q44-ter). This chromosomal location is associated with a number of cytogenetic aberrations including those involving brain developmental anomalies and tumorigenesis. These data suggest that C2H2-171 may play an important role in vertebrate brain development and function.

Amino Acid Sequence↗
PubMed1996

A gene map of the human genome.

The human genome is thought to harbor 50,000 to 100,000 genes, of which about half have been sampled to date in the form of expressed sequence tags. An international consortium was organized to develop and map gene-based sequence tagged site markers on a set of two radiation hybrid panels and a yeast artificial chromosome library. More than 16,000 human genes have been mapped relative to a framework map that contains about 1000 polymorphic genetic markers. The gene map unifies the existing genetic and physical maps with the nucleotide and protein sequence databases in a fashion that should speed the discovery of genes underlying inherited human disease. The integrated resource is available through a site on the World Wide Web at http://www.ncbi.nlm.nih.gov/SCIENCE96/.

Amino Acid Sequence↗
PubMed1996

Structure and chromosomal localization of the human homeobox gene Prox 1.

The genomic organization and nucleotide sequence of the human homeobox gene Prox 1 as well as its chromosomal localization have been determined. This gene spans more than 40 kb, consists of at least 5 exons, and encodes an 83-kDa protein. It shows 89% identity with the chicken sequence at the nucleotide level in the coding region, while the human and chicken proteins are 94% identical. Among the embryonic tissues analyzed (lens, brain, lung, liver, and kidney), the human Prox 1 gene is most actively expressed in the developing lens, similar to the expression pattern of the chicken Prox 1 gene. The Prox 1 gene was mapped to human chromosome 1q32.2-q32.3.

Adult↗
PubMed1996

Cloning, chromosomal localization, and tissue expression of autotaxin from human teratocarcinoma cells.

Autotaxin, a potent human tumor cell motility-stimulating exophosphodiesterase, was isolated and cloned from the human teratocarcinoma cell line NTera2D1. The deduced amino acid sequence for the teratocarcinoma autotaxin has 94% identity to the melanoma-derived protein, 90% identity to rat brain phosphodiesterase I/nucleotide pyrophosphatase (PD-I alpha), and 44% identity to the plasma cell membrane marker PC-I. Utilizing polymerase chain reaction screening of the CEPH YAC library, we localized the autotaxin gene to human chromosome 8q23-24. Northern blot analysis of relative mRNA from multiple human tissues revealed that autotaxin mRNA steady state expression is most abundant in brain, placenta, ovary, and small intestine.

Amino Acid Sequence↗
PubMed1996

[Tropisetron for the prevention of nausea and vomiting during chemotherapy: multicenter clinical study].

The antiemetic effect of tropisetron was studied in 97 cancer patients (67 men, 30 women) receiving cisplatin in doses of 75 mg/m2 or higher. On 279 chemotherapy cycles studied (max 6 per patient) 5 mg of tropisetron was administered once a day i.v on day 1 and p.o. on days 2 to 6. Efficacy preventing vomiting and nausea was measured in 24 hour period as: complete control O episodes, major control 1 to 2 episodes, minor control 3 to 4 episodes and no control 5 or more episodes. Satisfactory vomiting control (complete and major) was 69%, 63%, 82%, 88%, 96% and 96% in days 1 to 6 of cycle 1. Satisfactory nausea control (complete and major) for the same days was 70%, 66%, 72%, 85%, 92% and 97%. Similar data was obtained for the subsequent cycles. Complete vomiting control was obtained in 47%, 35%, 56%, 72%, 81% and 84% and for nausea in 42%, 39%, 48%, 64%, 81% and 87%. 19 patients presented adverse effects (19.6%). Only 2 headache episodes had a definite relation with the antiemetic drug. 12 patients discontinued the medication; 6 due to drug inefficacy, 2 to illness unrelated to the drug, 1 to lack of collaboration, and 3 due to other reasons. We conclude that tropisetron allows satisfactory control of acute and delayed vomiting in a high percentage of patients treated with high doses of cisplatin. The drug does not have significant secondary effects. Tropisetron administration in only one daily dose implies an evident advantage and a treatment cost reduction.

Adolescent↗
PubMed1996

Potentiation of cisplatin cytotoxicity by 9-aminocamptothecin.

Camptothecin (CPT) derivatives are presently in ongoing Phase I/II clinical trials. The interactions between 9-aminocamptothecin (9AC) and cisplatin (CDDP) have been studied in the IGROV-1 human ovarian cancer cell line used in the National Cancer Institute Drug Discovery Anticancer Screen. One-h simultaneous treatment with 9AC and CDDP produced synergistic cytotoxicity. Under these conditions, 9AC delayed the reversal of CDDP-induced DNA interstrand cross-links (ISCs) without modifying the maximum ISC frequency at 6 h after drug treatment. CDDP did not affect the amount and the kinetics of reversion of 9AC-induced DNA single-strand breaks. Simultaneous treatment with CDDP and 9AC prolonged the DNA synthesis inhibition produced by each drug alone. Consistently, flow cytometry analyses showed enhanced S-phase arrest in cells treated with the CDDP-9AC combination. The DNA polymerase inhibitor aphidicolin also increased the residual CDDP-induced ISCs. These results suggest that prolonged inhibition of DNA synthesis by CPTs potentiate the cytotoxicity of CDDP by inhibiting the reversal of CDDP-induced DNA damage. Therefore, the combination of CPTs and CDDP appears to be worthwhile in cancer chemotherapy.

Antineoplastic Agents↗
PubMed1995

An amino-terminal domain of Mxi1 mediates anti-Myc oncogenic activity and interacts with a homolog of the yeast transcriptional repressor SIN3.

Documented interactions among members of the Myc superfamily support a yin-yang model for the regulation of Myc-responsive genes in which transactivation-competent Myc-Max heterodimers are opposed by repressive Mxi1-Max or Mad-Max complexes. Analysis of mouse mxi1 has led to the identification of two mxi1 transcript forms possessing open reading frames that differ in their capacity to encode a short amino-terminal alpha-helical domain. The presence of this segment dramatically augments the suppressive potential of Mxi1 and allows for association with a mammalian protein that is structurally homologous to the yeast transcriptional repressor SIN3. These findings provide a mechanistic basis for the antagonistic actions of Mxi1 on Myc activity that appears to be mediated in part through the recruitment of a putative transcriptional repressor.

Amino Acid Sequence↗
PubMed1995

Comparative antimicrobial study of the resinous exudates of some Chilean Haplopappus (Asteraceae).

The antimicrobiol properties and preliminary chemical information of the resinous exudates from twigs and leaves of nine Haplopappus species from Chile: H. diplopappus; H. anthylloides; H. schumannii; H. cuneifolius; H. velutinus; H. uncinatus; H. multifolius, H. illinitus and H. foliosus are presented. The results show that those species of genus Haplopappus share similar antimicrobial activities although they differ dramatically in the chemical composition.

Anti-Bacterial Agents↗
PubMed1995

Self-esteem and value of health as determinants of adolescent health behavior.

PURPOSE: To study the relationship between personality attributes and health behaviors and practices during adolescence. DESIGN: We have studied a total of 100 subjects aged 12-13 and 16-17 years of both sexes. To examine self-esteem and the value of health in a series of habitual practices of health, a stepwise multiple regression analysis was undertaken. The instruments used were the Gordon Personal Profile (GPP) (1978) to evaluate self-esteem, the Costa et al.'s (1989) Value of Health Scale to estimate the value of health and, the Rivas Torres (1991) Health Behavior Questionnaire to measure health behavior. RESULTS: Self-esteem explains 39% of the mental health behavior and 5% of the social health behaviors. Meanwhile, the value of health, in the case of security behaviors, explains 13%, and in relation to personal health behaviors, 9%. CONCLUSIONS: The importance assigned to certain personality attributes in relation to adolescent health behavior shows the need for additional investigations that incorporate other variables and subject groups with different ages.

Adolescent↗