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Biomedical subjects

R Torres

Publications and source records attributed to R Torres.

At least 37 records · Page 2Linked to original sources
PubMed2005

Accumulation of the compatible solutes, glycine-betaine and ectoine, in osmotic stress adaptation and heat shock cross-protection in the biocontrol agent Pantoea agglomerans CPA-2.

AIMS: The effect of modifying the water activity (a(w)) of Pantoea agglomerans growth medium with the ionic solute NaCl on water stress resistance, heat-shock survival and intracellular accumulation of the compatible solutes glycine-betaine and ectoine were determined. METHODS AND RESULTS: The bacterium was cultured in an unmodified liquid medium or that modified with NaCl to 0.98 and 0.97 a(w), and viability of cells evaluated on a 0.96 a(w)-modified solid media to check water stress tolerance. Cells grown under ionic stress had better water stress tolerance than control cells. These cells also had cross-protection to heat stress (30 min, 45 degrees C). The modified cells accumulated substantial amounts of the compatible solutes glycine-betaine and ectoine in contrast to the control cells, which contained little or none of these two compounds. CONCLUSIONS: Improvement in osmotic and thermal tolerance of cells of the biocontrol agent P. agglomerans by modifying growth media with the ionic solute NaCl was achieved. The compatible solutes glycine-betaine and ectoine play a critical role in environmental stress tolerance improvement. SIGNIFICANCE AND IMPACT OF THE STUDY: This approach provides a method for improving the physiological quality of inocula and could have implications for formulation and shelf-life of biocontrol agents.

Adaptation, Physiological↗
PubMed2005

[Influence of maize kernel hardness on flour hydration and cooking properties].

Knowledge of the association between cooking properties and endosperm hardness may help nutritionist and processors to select raw materials for preparing maize based food products, particularly those eaten as cooked dispersions. Seven commercial maize cultivars differing in hardness were selected to evaluate endosperm hardness on the kernels and some characteristics such as composition and hydration and cooking properties on the grits obtained from those maizes. Results show that the differences in endosperm hardness (directly related to grits protein content) can explain the differences in swelling and amylographic consistencies values. Cultivars with the hardest endosperm show the lowest values at high temperature. They also show the lowest amylographic consistencies. On the other hand softer endosperms present the highest swelling power and the highest amylographic consistencies. These differences are attributed to the restriction for starch swelling caused by the protein matrix. Endosperm hardness measurements and swelling power at 95 degrees C, can be useful to select cultivars that are going to be used to prepare maize based foods like atoles, polenta, etc.

Cooking↗
PubMed2004

Prevalence of delirium in a geriatric convalescence hospitalization unit: patient's clinical characteristics and risk precipitating factor analysis.

The aim was to evaluate the prevalence of delirium among patients discharged from an acute care hospital and admitted to a geriatric convalescence unit (GCU), and to analyze patient's characteristics and risk precipitating factors. Sixty-eight patients were analyzed during a 2-week period. The confusion assessment method (CAM) was used to detect delirium. The precipitating factors evaluated were: major surgery-intensive care unit(ICU) stay, pulmonary and heart failure, acute infections, metabolic disorders/anemia,psychoactive medications, other drugs, severe pain, changing environmental influences and others. According to CAM, fifteen patients presented delirium (22%), and in 14 of them(93.3 %) the delirium was developed before admission at GCU. The precipitating factors in the studied population were the following: changing environmental influences in 66 patients(97%) (15 with delirium and 51 without delirium); other drugs 56 (82.3 %) (11 vs. 45);others 56 (82.3%) (9 vs. 24); psychoactive medications 50 (73.5%) (12 vs. 38); acute infections 48 (70.5 %) (13 vs. 35); metabolic disorders/anemia 40 (58.8 %) (9 vs. 31); major surgery-ICU stay 28 (41 .1%) (8 vs. 20); severe pain 26 (38.2%) (6 vs. 20); pulmonary and heart failure 22 (32.3%) (5 vs. 17). The univariant analysis showed that, none of the precipitating factors studied was significantly related to delirium. Seventy-two patients (91.1%) had simultaneously >3 precipitating factors. There were 16 patients with >6 precipitating factors, 7 of 15 with delirium and 9 of the 53 without delirium (46.6 % vs 16.9 %) (p < 0.05). The prevalence of delirium has been 22 %. Most of the patients had developed delirium before the admission at GCU. A high proportion of patients had >3 precipitating factors. In the study the presence of > 6 precipitating factors simultaneously has been significantly related to delirium.

Aged↗
PubMed2004

Functional neurosurgery in the MRI environment.

OBJECTIVE: The purpose of this study was to evaluate the feasibility of microelectrode recording, electrical stimulation, and electrode position checking during functional neurosurgical procedures (DBS, lesion) in the interventional magnetic resonance imaging (iMRI) environment. METHODS: Seventy-six surgical procedures for DBS implant or radiofrequency lesion were performed in an open 0.2 T MRI operating room. DBS implants were performed in 54 patients (72 surgical procedures) and unilateral radiofrequency lesions in three for a total of 76 surgeries in 57 patients. Electrophysiological studies including macrostimulation and microelectrode recordings for localization were obtained in the 0.5 to 10 mT fringes of the magnetic field in 51 surgeries. MRI confirmation of the electrode position during the procedure was performed after electrophysiological localization. RESULTS: The magnetic field associated with the MRI scanner did not contribute significant noise to microelectrode recordings. Anatomical confirmation of electrode position was possible within the MRI artifact from the DBS hardware. Symptomatic hemorrhage was detected in two (2.6 %) patients during the operation. Image quality of the 0.2 T MRI scan was sub-optimal for anatomical localization. However, image fusion with pre-operative scans permitted excellent visualization of the DBS electrode tip in relation to the higher quality 1.5 T MRI anatomical scans. CONCLUSION: This study shows that conventional stereotactic localization, microelectrode recordings, electrical stimulation, implant of DBS hardware, and radiofrequency lesion placement are possible in the open 0.2 T iMRI environment. The convenience of having an imaging modality that can visualize the brain during the operation is ideal for stereotactic procedures.

Adolescent↗
PubMed2003

Liquid formulation of the biocontrol agent Candida sake by modifying water activity or adding protectants.

AIMS: To evaluate the effect of modification of water activity (aw) and the addition of protective substances in the preservation medium of liquid formulations of the biocontrol agent Candida sake stored at 4 and 20 degrees C. METHODS AND RESULTS: The aw of the preservation medium of C. sake was modified from 0.72 to 0.95 by adding glycerol or polyethylene glycol (PEG). Moreover, several protectant substances at different concentrations were evaluated. Modification of lower aw-levels (0.721-0.901) with glycerol did not maintain the viability of the yeast cells. Higher aw-levels (0.93-0.95) with either glycerol or PEG improved the viability but not at acceptable viability levels. C. sake cells maintained viabilities >60% when sugars, such as trehalose, and polyols, such as glycerol and PEG were used as protectants in liquid formulations. Moreover, liquid formulations of C. sake stored at 4 degrees C showed higher number of viable counts than at 20 degrees C. When different sugars were tested, all of them, except 10% fructose, resulted in a viability higher than 50% of the C. sake formulations. Biocontrol of liquid formulation treatments was similar to fresh cells in controlling Penicillium expansum on wounded apples. CONCLUSIONS: Sugars such as lactose and trehalose could be considered as good protectants in order to obtain liquid formulations of C. sake cells as they maintain the viability >70% for 4 months at 4 degrees C. SIGNIFICANCE AND IMPACT OF STUDY: This study shows that a suitable liquid formulation for commercial application can be produced with high viability and conservation of biocontrol efficacy. Moreover, if 10% lactose is the protectant used in the formulation, the economic costs would not be limiting for industrial production.

Candida↗
PubMed2002

Six years of experience in laparoscopic surgery of esophageal achalasia.

BACKGROUND: We show the experience of 6 years in laparoscopic surgical therapy of esophageal achalasia, performing of the Heller-Dor or Heller-Toupet operation, with particular regard to the technical aspect. METHODS: One hundred and ten laparoscopic interventions were done between November 1995 and December 2001. We studied operative time in hiatus approach, esophagocardiomyotomy, transoperative endoscopy, and anti-reflux procedure. We also analyzed the relation between complications and clinical evolution of disease with clinical stage. RESULTS: The mean surgical time of the intervention is 138 min, and it is significantly increased by transoperative endoscopic control; conversion to open surgery was not necessary. Clinical results are classified as excellent in 103 patients. Morbidity was 6%. CONCLUSION: This surgical procedure is a first line in the treatment of esophageal achalasia. It is necessary to have special care in early diagnostic cases to avoid electrosurgical injury.

Adolescent↗
PubMed2002

Effect of package and storage conditions on viability and efficacy of the freeze-dried biocontrol agent Pantoea agglomerans strain CPA-2.

AIMS: To reduce concentrations of protective and rehydrating media and to evaluate the effect of storage temperature, packaging and atmosphere conditions on the stability of freeze-dried Pantoea agglomerans cells. Efficacy against Penicillium digitatum of freeze-dried cells in orange fruits was also evaluated. METHODS AND RESULTS: Several concentrations of protective and rehydration media were tested to reduce processing costs. Freeze-dried cells were packed in glass vials or plastic bags under vacuum or nitrogen conditions at 4 and 25 degrees C. After 1 and 3 months, efficacy of freeze-dried P. agglomerans against P. digitatum was tested. CONCLUSIONS: The results indicate that it is possible to reduce the concentration of non-fat skimmed milk as a rehydration medium from 10% to 1%, maintaining viabilities of 100%. Moreover, freeze-dried cells could be stored in glass vials or in high barrier plastic bags at 4 degrees C for 3 months while maintaining high viabilities and efficacy against P. digitatum. SIGNIFICANCE AND IMPACT OF THE STUDY: The major obstacle in the commercialization of biocontrol products is the development of a shelf-stable formulated product that retains biocontrol activity at a level similar to that of fresh cells. This study suggests that it is possible to maintain viability and efficacy of freeze-dried P. agglomerans cells for at least 3 months.

Atmosphere↗
PubMed2002

Mast cells induce upregulation of P-selectin and intercellular adhesion molecule 1 on carotid endothelial cells in a new in vitro model of mast cell to endothelial cell communication.

It is suggested that mast cells contribute to cell recruitment in inflammation through the upregulation of endothelial adhesion molecules. P-selectin and intercellular adhesion molecule(ICAM)-1 are two key adhesion molecules that have been associated indirectly with mast cell activity. The canine C2 mastocytoma cell line and primary cultures of canine carotid endothelial cells were used to establish a new in vitro model to help study the interaction between mast cells and endothelial cells. Carotid endothelial cells were incubated with mast cell mediators to uncover their effect on endothelial ICAM-1 and P-selectin expression. To assess the relative contributions of tumour necrosis factor (TNF)-alpha and histamine to such effect, an H1 antihistamine and a TNF-alpha blocking antibody were used. Prior to activation by mast cell mediators, P-selectin was expressed only within the cytoplasm, and ICAM-1 was constitutively expressed on the surface of the canine carotid endothelial cells. Both adhesion molecules were enhanced significantly and strongly upon mast cell activation at various time points. Unstored TNF-alpha was fully responsible for ICAM-1 upregulation. P-selectin was up-regulated by both preformed and newly synthesized mast cell mediators, but neither histamine nor TNF-alpha accounted for such an effect. Therefore,a new model is proposed in which the pro-inflammatory effect of mast cells on endothelial cells can be studied in vitro. In this model, it has been demonstrated that only TNF-alpha accounts for the overexpression of ICAM-1 induced by mast cells, and that mast cells up-regulate P-selectin expression through a histamine-independent mechanism.

Animals↗
PubMed2002

Antinerve growth factor treatment prevents intestinal dysmotility in Trichinella spiralis-infected rats.

Nerve growth factor (NGF) could be involved in the development of hyperalgesia as well as in nervous remodeling consequence of inflammation. Both dysmotility and increase of visceral sensitivity have been described in functional gastrointestinal disorders such as irritable bowel syndrome. Trichinella spiralis-infected rats show an exacerbated spontaneous motility and a significant increase of the excitatory response to cholecystokinin (CCK), both associated with a reversible inflammatory process and the hypertrophy of the muscle layers. In this study we determined the intestinal expression of NGF mRNA by polymerase chain reaction and NGF by enzyme-linked immunosorbent assay. We implanted serosal strain gauge transducers on duodenum, jejunum, and ileum of anesthetized Sprague-Dawley rats to record circular muscle contractions. The experimental protocol included the evaluation of intestinal spontaneous motor activity (SMA), the response to CCK-8, and the ascending contraction induced by electrical mucosal stimulation. This protocol was performed in healthy and infected nontreated rats, in healthy rats with an NGF antibody treatment (1.6 mg/rat i.p.), and in infected rats with the same treatment applied at 0 or 3 days postinfection. NGF and NGF mRNA levels in the bowel were increased during inflammation. Although anti-NGF treatments did not prevent or reverse inflammatory response, the treatment was effective in preventing the motor alterations induced by the T. spiralis infection, i.e., inhibited increased SMA, reversed altered response to CCK, and reversed in part exacerbated response to electrical stimulation.

Animals↗
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↗