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Biomedical subjects

R Torres

Publications and source records attributed to R Torres.

At least 19 recordsLinked to original sources
PubMed2001

Human Raphe Magnus Nucleus: a morphometric Golgi-Cox study with emphasis on sex differences.

The number and proportion of neurons according to their type and size in the Raphe Magnus Nucleus stained by the Golgi-Cox and Nissl methods were compared in male and female infants. Four female/male pairs aged from 2 to 150 days were studied. While females showed more neurons than males, males showed a higher proportion of large multipolar (more than 40 microm) and fusiform neurons (more than 20 microm) but not of ovoid neurons (more than 15 microm). These differences varied according to the type of cells and age of infants. Some of these results are similar to those found in the human Median Raphe Nucleus with the same methods.

Cell Count↗
PubMed2001

Translaparoscopic jejunal approach for benign stricture of Roux-en-Y hepaticojejunostomy.

Although the Roux-en-Y hepaticojejunostomy is the most common surgical procedure for the treatment of bile duct strictures, providing durable long-term results in most patients, when a stricture is present, the management is more difficult, and a reoperation generally will be proposed. However, balloon dilation and endoscopic stenting using the percutaneous transhepatic or transjejunal approach under fluoroscopic guidance have been suggested as the first step or even as definitive management in treating these patients. We present a case report of a patient with a benign biliary stricture as a consequence of a Roux-en-Y hepaticojejunostomy, who was managed through a translaparoscopic jejunal approach because of an unfixed Roux-en-Y loop. In conclusion, we recommend this strategy as the first step for managing the restricture of Roux-en-Y hepaticojejunostomy in patients with an unfixed Roux-en-Y loop.

Adult↗
PubMed2001

Heliotropium huascoense resin exudate: chemical constituents and defensive properties.

From the resinous exudate of Heliotropium huascoense a new compound, rel-(8R,9R)-carrizaloic acid, (1) (3-[rel-(8R,9R-9-hydroxy-9,13,13-trimethyl-12-oxo-10-cyclohexenyl)methyl]-4-methoxybenzoic acid), and three known flavonoids, [3-methylgalangin, 3,7-dimethylgalangin, and (-)-alpinone] have been isolated. The structure of 1 was determined by spectral and chemical methods. Several plant defensive properties of 1 (insecticidal and antifungal) have been evaluated.

Animals↗
PubMed2001

Mutation screening of the Wolfram syndrome gene in psychiatric patients.

Wolfram syndrome, a rare autosomal recessive neurodegenerative disorder, was originally described as a combination of familial juvenile-onset diabetes mellitus and optic atrophy. It was later demonstrated that Wolfram syndrome patients were highly prone to psychiatric disorders. Mutations in exon 8 of the Wolfram syndrome gene account for 88% of the patients with Wolfram syndrome. To examine whether the gene responsible for causing Wolfram syndrome is involved in psychiatric disorders, we screened exon 8 of the Wolfram syndrome gene for mutations in 119 patients with schizophrenia, one patient with schizoaffective disorder, 12 patients with bipolar disorder and 15 patients with major depression, using sequence analysis. In Wolfram syndrome patients, this gene has been shown to have primarily nonsense or frameshift mutations, which would result in a premature truncation of the protein. None of the psychiatric patients screened in this study carried these types of mutations. We identified, however, 24 new variations whose significance remains to be determined.

Bipolar Disorder↗
PubMed2001

Validation of the Delirium Rating Scale-revised-98: comparison with the delirium rating scale and the cognitive test for delirium.

The DRS-R-98, a 16-item clinician-rated scale with 13 severity items and 3 diagnostic items, was validated against the Cognitive Test for Delirium (CTD), Clinical Global Impression scale (CGI), and Delirium Rating Scale (DRS) among five diagnostic groups (N=68): delirium, dementia, depression, schizophrenia, and other. Mean and median DRS-R-98 scores significantly (P<0.001) distinguished delirium from each other group. DRS-R-98 total scores correlated highly with DRS, CTD, and CGI scores. Interrater reliability and internal consistency were very high. Cutoff scores for delirium are recommended based on ROC analyses (sensitivity and specificity ranges: total, 91%-100% and 85%-100%; severity, 86%-100% and 77%-93%, respectively, depending on the cutoffs or comparison groups chosen). The DRS-R-98 is a valid measure of delirium severity over a broad range of symptoms and is a useful diagnostic and assessment tool. The DRS-R-98 is ideal for longitudinal studies.

Adolescent↗
PubMed2001

Worsening of post-traumatic stress disorder symptoms with cognitive decline: case series.

We present three cases of post-traumatic stress disorder (PTSD) symptoms associated with cognitive decline. Patient age ranged from 57 to 70 years old and all patients had war-related PTSD. In each case, the patient had a history of PTSD that was under fairly good control until the onset of cognitive impairment due to Alzheimer's disease or vascular or alcohol-related dementia. These cases suggest that neurodegeneration of memory pathways may disinhibit symptoms of PTSD.

Aged↗
PubMed2001

[Prevalence of risk for mental disorders among undergraduate medical students at the Medical School of the Catholic University of Chile].

BACKGROUND: Stress caused by the high physical, intellectual and emotional demands imposed to medical students, renders them specially susceptible to the development of mental disorders. AIM: To assess the prevalence of risk for mental disorders among undergraduate students at the Medical School of the Catholic University of Chile. MATERIAL AND METHODS: The Twelve Item General Health Questionnaire (GHQ 12) was voluntarily answered by medical students from the first to the fifth year. RESULTS: Sixty eight percent of the total population (305 students) answered the questionnaire. Forty one percent of students were at risk, defined as scoring five or more points in the GHQ 12. The average score was 3.9 +/- 2.2. First year students had a higher score than fourth year students (4.6 +/- 2.2 and 3.4 +/- 2.1 points respectively, p < 0.05). No gender differences were observed. CONCLUSIONS: Our results are similar to those of other publications concerning psychiatric risk among medical students.

Adolescent↗
PubMed2001

[Fever of unknown origin in HIV positive patients].

OBJECTIVES: To describe the clinical presentation of FUO in patients infected with HIV and to asses the diagnostic usefulness in this population of several test usually recommended in the study of FUO. PATIENTS AND METHODS: We studied the clinical charts of all patients with HIV that required admission to our Hospital during a 23-month period. FUO was defined according to Petersdorf's modified criteria. Fifty-four patients fulfilled study criteria during the entry period. RESULTS: A cause of fever was identified for 48 patients (89%). Tuberculosis, disseminated atypical mycobacteriosis and Leishmaniasis can explain 68% of them. Examination of bone marrow aspirates, lymph node aspirates and biopsy, and culture of clinical specimens for mycobacteria were the procedures with the highest diagnostic yield. CONCLUSIONS: Mycobacterial infection should be considered as a first-line diagnosis in HIV-patients with FUO. It is possible to predict the diagnosis of tuberculosis infection with a high level of confidence (90.5%) through a logistic regression model based on easily obtainable parameters.

AIDS-Related Opportunistic Infections↗
PubMed2000

Etoposide stimulates 1,25-dihydroxyvitamin D3 differentiation activity, hormone binding and hormone receptor expression in HL-60 human promyelocytic cells.

The simultaneous administration of the DNA topoisomerase II inhibitor etoposide (0.15 mM) and 1,25-dihydroxyvitamin D3 (VD3) (10 nM) synergistically induced the differentiation of HL-60 human promyelocytic leukemia cells. Similar results were obtained using U-937 human promonocytic cells, or the topoisomerase II inhibitors doxorubicin (15 nM) and mitoxantrone (2.5 nM). When sequential treatments were used, pre-incubation with VD3 had little effect on the subsequent action of etoposide, while pre-incubation with etoposide greatly potentiated the subsequent action of VD3. In addition, etoposide treatment stimulated VD3 binding activity and increased VD3 receptor mRNA and protein levels. The increase in hormone receptor expression may explain, at least in part, the capacity of topoisomerase inhibitors to potentiate the differentiation inducing activity of VD3.

Apoptosis↗
PubMed2000

Correlation between in vitro and in vivo antifungal activities in experimental fluconazole-resistant oropharyngeal and esophageal candidiasis.

Oropharyngeal and esophageal candidiasis (OPEC) is a frequent opportunistic mycosis in immunocompromised patients. Azole-resistant OPEC is a refractory form of this infection occurring particularly in human immunodeficiency virus (HIV)-infected patients. The procedures developed by the Antifungal Subcommittee of the National Committee for Clinical Laboratory Standards (NCCLS) are an important advance in standardization of in vitro antifungal susceptibility methodology. In order to further understand the relationship between NCCLS methodology and antifungal therapeutic response, we studied the potential correlation between in vitro susceptibility to fluconazole and in vivo response in a rabbit model of fluconazole-resistant OPEC. MICs of fluconazole were determined by NCCLS methods. Three fluconazole-susceptible (FS) (MIC, </=0.125 microgram/ml) and three fluconazole-resistant (FR) (MIC, >/=64 microgram/ml) isolates of Candida albicans from prospectively monitored HIV-infected children with OPEC were studied. FR isolates were recovered from children with severe OPEC refractory to fluconazole, and FS isolates were recovered from those with mucosal candidiasis responsive to fluconazole. Fluconazole at 2 mg/kg of body weight/day was administered to infected animals for 7 days. The concentrations of fluconazole in plasma were maintained above the MICs for FS isolates throughout the dosing interval. Fluconazole concentrations in the esophagus were greater than or equal to those in plasma. Rabbits infected with FS isolates and treated with fluconazole had significant reductions in oral mucosal quantitative cultures (P < 0.001) and tissue burden of C. albicans in tongue, soft palate, and esophagus (P < 0.001). In comparison, rabbits infected with FR isolates were unresponsive to fluconazole and had no reduction in oral mucosal quantitative cultures or tissue burden of C. albicans versus untreated controls. We conclude that there is a strong correlation between in vitro fluconazole susceptibility by NCCLS methods and in vivo response to fluconazole therapy of OPEC due to C. albicans.

Animals↗
PubMed2000

Cell-volume changes and ion conductances in amphibian gallbladder epithelium.

Cell-volume regulation after hyposmotic swelling is common in transporting epithelial cells. Acute regulatory volume decrease is mediated in several cell types by loss of K(+) and Cl(-) via channels either activated by the swelling phenomenon or active in the cell membrane prior to swelling. In the last two decades, it has become clear that many features of cell-volume regulation mediated by ion fluxes vary considerably among cell types. In some instances, the ion channel activation, although demonstrable, is insufficient to account, on the basis of ion fluxes, for the measured cell volume changes. Here we review the case of a salt-transporting epithelium in which hyposmotic cell swelling activates plasma membrane K(+) channels, but at the same time inhibits Cl(-) channels, thus preventing an acute volume-regulatory response. The sequence of events following cell swelling appears to be as follows: K(+) channels are activated by membrane stretch, the cell membrane hyperpolarizes (the voltage moves closer to the K(+) equilibrium potential) and this hyperpolarization reduces the Cl(-) conductance, likely by a reduction in open probability of voltage-sensitive Cl(-) channels. The significance of this phenomenon may be related to the preservation of intracellular Cl(-) rather than cell volume, or to a physiological 'need' to prevent shrinkage of cells stimulated by hormones or other mediators.

Amphibians↗
PubMed2000

Continuous intravenous flumazenil infusion for benzodiazepine poisoning.

This is the first US report of continuous iv flumazenil infusion for benzodiazepine poisoning. A MEDLINE search from 1966 to 1999 revealed no similar reports in the US literature. A 24-y-o woman ingested 50, 2 mg (=100 mg) flunitrazepam tablets in a suicide attempt. She presented 30 min after ingestion with a temperature of 36.5 C, blood pressure of 90/36 mmHg, pulse of 84/min, and shallow respirations of 8/min. Her Glasgow coma scale (GCS) was 8. Her ECG showed sinus rhythm at 80/min, a QRS axis of 30 with no terminal 40 msec deviation, and a QRS interval of 84 msec. She received 0.2 mg flumazenil iv and her GCS improved to 15. She was orogastrically lavaged and given 50 g of activated charcoal. Resedation to a GCS of 8 recurred twice, requiring additional 0.3 mg and 0.5 mg boluses of flumazenil iv, totaling 1.0 mg over 1 h. Then, a continuous flumazenil infusion was started at 1.0 mg/h, maintaining her GCS at 15. Fourteen h later, the continuous flumazenil infusion was terminated, resulting in resedation and clinical hypoventilation. Flumazenil infusion was restarted at 1.0 mg/h with resolution of sedation and hypoventilation. Thirty h after overdose flumazenil infusion was terminated without resedation or hypoventilation. Continuous iv flumazenil infusion is not US Food and Drug Administration approved, and further study is necessary in carefully selected patients to determine its safety and efficacy.

Adult↗
PubMed1999

Genomic structure and localization of the human protein phosphatase 2A BRgamma regulatory subunit.

In the course of our analysis of genomic sequence from the human chromosome 4p16.1 region harboring both the Wolfram and Ellis van Creveld syndrome genes we have identified a sequence with high homology (98% at the amino acid level) to the rat cDNA coding for the protein phosphatase 2A BRgamma (PP2ABRgamma) regulatory subunit. Although the human cDNAs for both the BRalpha and BRbeta isoforms have been described previously, the BRgamma subunit has not yet been identified in humans. Here we describe the precise genomic organization and genetic localization of the human PP2ABRgamma gene.

Amino Acid Sequence↗
PubMed1999

B cell development in the spleen takes place in discrete steps and is determined by the quality of B cell receptor-derived signals.

Only mature B lymphocytes can enter the lymphoid follicles of spleen and lymph nodes and thus efficiently participate in the immune response. Mature, long-lived B lymphocytes derive from short-lived precursors generated in the bone marrow. We show that selection into the mature pool is an active process and takes place in the spleen. Two populations of splenic B cells were identified as precursors for mature B cells. Transitional B cells of type 1 (T1) are recent immigrants from the bone marrow. They develop into the transitional B cells of type 2 (T2), which are cycling and found exclusively in the primary follicles of the spleen. Mature B cells can be generated from T1 or T2 B cells. Mice with genetic deletions of elements participating in the B cell receptor signaling cascade display developmental arrest at the T1 or T2 stage. The analysis of these defects showed that the development of T2 and mature B cells from T1 precursors requires defined qualitative and quantitative signals derived from the B cell receptor and that the induction of longevity and maturation requires different signals.

Animals↗
PubMed1999

Enhanced production of penicillin V acylase from Streptomyces lavendulae.

A 28 degrees C, Streptomyces lavendulae produced high levels of penicillin V acylase (178 IU/l of culture) when grown on skim milk as the sole nutrient source for 275 h. The enzyme showed catabolite repression by glucose and was produced in the stationary phase of growth. Penicillin V was a good inducer of penicillin V acylase formation, while phenoxyacetic acid, the side-chain moiety of penicillin V, did not alter enzyme production significantly. The enzyme was stable between pH 6 and 11 and at temperatures from 20 degrees C to 55 degrees C. This extracellular enzyme was able to hydrolyse natural penicillins and unable to hydrolyse penicillin G.

Penicillin Amidase↗
PubMed1999

Rolipram inhibits staphylococcal enterotoxin B-mediated induction of the human skin-homing receptor on T lymphocytes.

The cutaneous lymphocyte-associated antigen defines T lymphocytes with cutaneous tropism under inflammatory conditions. Bacterial infections participate in cutaneous inflammations, such as atopic dermatitis or psoriasis. Bacterial superantigens, such as staphylococcal enterotoxin B, can activate peripheral blood mononuclear cells to induce effector T cells bearing the T cell skin homing receptor cutaneous lymphocyte-associated antigen via enhancement of interleukin-12 production. We have identified and characterized the anti-inflammatory effects of different phosphodiesterase inhibitors on this system. Our data indicate that the selective type 4 phosphodiesterase inhibitor rolipram inhibits the Staphylococcal enterotoxin B-mediated generation of cutaneous lymphocyte-associated antigen positive CD3+ cells from peripheral blood mononuclear cells by reducing interleukin-12 production in a concentration-dependent manner. Conversely, type 3 phosphodiesterase or type 5 phosphodiesterase selective inhibitors were not effective. The rolipram inhibitory effect was on interleukin-12 production, as exogenously added interleukin-12 could revert rolipram suppression. These results suggest that selective type 4 phosphodiesterase inhibition may have beneficial effects on T cell mediated skin inflammatory processes characterized by the presence of bacterial infections, that are thought to exacerbate ongoing skin inflammation.

Animals↗