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Biomedical subjects

V Calvo

Publications and source records attributed to V Calvo.

At least 37 records · Page 2Linked to original sources
PubMed2000

Identifying dementia in the primary care practice.

BACKGROUND: The purpose of this study was to evaluate the utility (i.e., positive and negative predictive value) of the 7 Minute Screen in identifying patients with probable Alzheimer's disease (AD) in a primary care practice. A second objective was to estimate the number of undiagnosed AD patients in a typical primary care practice. METHODS: One hundred thirty-seven successive admissions (96%) of patients over the age of 60 to a primary care practice over a 53-day period who completed informed consent documents were administered the 7 Minute Screen. All patients who screened positive (n = 13) and a random sample of those who screened negative (n = 26) returned for full diagnostic evaluation. Positive predictive value (PPV) and negative predictive value (NPV) of the 7 Minute Screen were determined using the criterion standard of clinical diagnosis established by examination, history, and laboratory studies. Test-retest reliability and time for administration were also determined. RESULTS: Of the 137 patients evaluated, 13 screened positive and 124 screened negative. Eleven of the 13 patients who screened positive were willing to return to the primary care practice for follow-up evaluation. A random sample of 26 patients who screened negative all agreed to return for follow-up evaluation. Of the 11 patients who screened positive and who returned for evaluation, 10 were subsequently diagnosed with probable AD. The remaining patient was diagnosed with mixed dementia. The caregivers of the two patients who refused to return were contacted and both indicated that the patients were having significant cognitive problems as verified by an activities of daily living scale. Of the 26 patients who screened negative, 25 were judged to be cognitively normal and the 26th was judged to have mild cognitive impairment. DISCUSSION: In successive admissions of patients over the age of 60 in a primary care practice, the 7 Minute Screen showed a PPV of 91% and an NPV of 96% in identifying patients who were subsequently identified with AD or other dementing disorder. These data suggest that this may be a useful instrument in identifying patients who should undergo diagnostic evaluation for AD and other dementing disorders. Additionally, extrapolation from the data in this practice suggests that there may be between 75 and 100 AD patients in the typical primary care practice, many of whom may not be diagnosed.

Aged↗
PubMed2000

The central role of the prefrontal cortex in directing attention to novel events.

The physiological basis for the striking decrease of attention to novel events following frontal lobe injury is poorly understood. In this study, event-related potentials (ERPs) were recorded from patients with frontal lobe damage and matched subjects, who controlled the duration of viewing of background, novel and target stimuli. Frontal lobe patients did not differ from normal controls in terms of age, education, estimated IQ or mood. However, they were judged to be more apathetic as measured by self-report and informants' ratings. Patients with frontal lobe damage exhibited markedly reduced amplitude of the novelty P3 response and the duration of viewing of novel stimuli. In contrast, injury to the frontal lobes had a limited impact on P3 amplitude and behavioural responses (viewing duration and reaction time) to target stimuli. A strong correlation was found between measures of apathy and both attenuated P3 amplitude and viewing duration in response to novel but not target stimuli. Differences in amplitude of the novelty P3 response explained a large portion of the variance associated with duration of viewing of novel stimuli. After controlling for the influence of P3 amplitude, there was no association between frontal lobe injury and reduced viewing of novel stimuli. The results of this study suggest that frontal lobe damage leads to diminished visual attention to novel events through its disruption of neural processes underlying the novelty P3 response. These processes appear to regulate the allocation of attentional resources and early exploratory behaviours, and are not limited to immediate orienting responses. Damage to the frontal lobes may prevent the generation of a signal which indicates that a novel event in the environment requires additional attention due to its potential behavioural significance. The disruption of these processes is likely to contribute to the apathy observed in patients after injury to the frontal lobes.

Adult↗
PubMed2000

Disruption of attention to novel events after frontal lobe injury in humans.

OBJECTIVE: To investigate whether frontal lobe damage in humans disrupts the natural tendency to preferentially attend to novel visual events in the environment. METHODS: Nine patients with chronic infarctions in the dorsolateral prefrontal cortex (DLPFC) and 23 matched normal controls participated in a study in which subjects viewed repetitive background stimuli, infrequent target stimuli, and novel visual stimuli (for example, fragmented or "impossible" objects). Subjects controlled viewing duration by a button press that led to the onset of the next stimulus. They also responded to targets by pressing a foot pedal. The amount of time spent looking at the different kinds of stimuli, and the target detection accuracy and speed served as dependent variables. RESULTS: Overall, normal controls spent significantly more time than frontal lobe patients looking at novel stimuli. Analysis of responses across blocks showed that initially frontal lobe patients behaved like normal controls by directing more attention to novel than background stimuli. However, they quickly began to distribute their viewing time evenly between novel and background stimuli, a pattern that was strikingly different from normal controls. By contrast, there were no differences between frontal lobe patients and normal controls for viewing duration devoted to background and target stimuli, target detection accuracy, or reaction time to targets. Frontal lobe patients did not differ from normal controls in terms of age, education, estimated IQ, or mood, but were more apathetic as measured by self report and informants' judgments. Attenuated responses to novel stimuli significantly correlated with degree of apathy. CONCLUSIONS: This study demonstrates that DLPFC injury selectively impairs the natural tendency to seek stimulation from novel and unusual stimuli. These data provide the first quantitative behavioural demonstration that the human frontal lobes play a critical part in directing and sustaining attention to novel events. The impairment of novelty seeking behaviour may contribute to the characteristic apathy found in patients with frontal lobe injury.

Aged↗
PubMed2000

The influence of stimulus deviance on electrophysiologic and behavioral responses to novel events.

This study investigated the role of stimulus deviance in determining electrophysiologic and behavioral responses to "novelty." Stimulus deviance was defined in terms of differences either from the immediately preceding context or from long-term experience. Subjects participated in a visual event-related potential (ERP) experiment, in which they controlled the duration of stimulus viewing with a button press, which served as a measure of exploratory behavior. Each of the three experimental conditions included a frequent repetitive background stimulus and infrequent stimuli that deviated from the background stimulus. In one condition, both background and deviant stimuli were simple, easily recognizable geometric figures. In another condition, both background and deviant stimuli were unusual/unfamiliar figures, and in a third condition, the background stimulus was a highly unusual figure, and the deviant stimuli were simple, geometric shapes. Deviant stimuli elicited larger N2-P3 amplitudes and longer viewing durations than the repetitive background stimulus, even when the deviant stimuli were simple, familiar shapes and the background stimulus was a highly unusual figure. Compared to simple, familiar deviant stimuli, unusual deviant stimuli elicited larger N2-P3 amplitudes and longer viewing times. Within subjects, the deviant stimuli that evoked the largest N2-P3 responses also elicited the longest viewing durations. We conclude that deviance from both immediate context and long-term prior experience contribute to the response to novelty, with the combination generating the largest N2-P3 amplitude and the most sustained attention. The amplitude of the N2-P3 may reflect how much "uncertainty" is evoked by a novel visual stimulus and signal the need for further exploration and cognitive processing.

Adult↗
PubMed2000

An electrophysiological index of stimulus unfamiliarity.

This study investigated the functional significance of the N2 response to novel stimuli. In one condition, background, target, and deviant stimuli were simple geometric figures. In a second condition, all stimulus types were unfamiliar/unusual figures. In a third condition, background and target stimuli were unusual figures and deviant stimuli were simple shapes. Unusual figures, whether they were deviant, target, or background stimuli, evoked larger N2 responses than their simple, familiar counterparts. N2 elicited by an unusual background stimulus was larger than that evoked by simple, deviant stimuli, a pattern opposite that exhibited by the subsequent P3. Deviance from immediate context had limited influence over N2 amplitude. The results suggest that novelty N2 and novelty P3 reflect the processing of different aspects of "novel" visual stimuli. The novelty P3 is particularly sensitive to deviation from immediate context. In contrast, the novelty N2 is sensitive to deviation from long-term context that renders a stimulus unfamiliar and difficult to encode.

Adult↗
PubMed1999

Tracheoplasty in a large tracheoesophageal fistula.

Postintubation tracheoesophageal fistulas (TEFs) are severe lesions that can be associated with tracheal stenosis and therapeutic difficulties. A case is reported of a woman with TEF and postintubation tracheal stenosis with 6.5 cm of affected trachea, and total esophageal exclusion. A tracheoplasty method is described patching the loss of the tracheal membranous wall with the posterior esophageal wall. In a final step, a self-expanded tracheal stent and esophagocolic bypass were added.

Esophagus↗
PubMed1999

[The prognosis following surgical resection of small-cell nonanaplastic bronchogenic carcinoma according to the new staging guideline: an analysis of 1433 patients].

OBJECTIVE: To validate current guidelines for staging bronchogenic lung carcinoma. METHODS: Between 1969 and 1996, small-cell non-anaplastic tumors of bronchogenic carcinoma classified by the recently proposed TNM guidelines of the Spanish Society of Pneumology and Chest Surgery (SEPAR) were resected from 1,433 patients. We used the Kaplan-Meier method to calculate survival and compared the curves using a log-rank test. RESULTS: A stage IA classification was given to 142 patients and IB to 575. Thirty-seven cases were classified IIA and 336 were IIB. Of the latter, 177 were T2N1M0 and 159 were T3N0M0. Two hundred forty-eight patients were in stage IIIA, 54 T3N1M0, 23 T1N2M0, 120 T2N2M0 and 51 T3N2M0. Ninety-five stage IIIB patients were classified as follows: 37 T4N0M0, 35 T4N1M0, and 23 T4N2M0. Five-year survival for IA patients, at 75% was significantly better than the 60% rate for IB patients (p = 0.0021). Likewise, the prognosis for stage IIA, where five-year survival was 57%, was significantly better than for IIB at 39% (p = 0.0434). The prognosis for patients classified as T1NM0 was better than for those classified as T2N1M0, which was 38% (p = 0.0320). The survival of those classified as T3N0M0 (42%) was not significantly different from that of T1N1M0 (p = 0.1754) or T2N1M0 (p = 0.5360) patients. We found no significant difference between T1N1M0 and stage IB (p = 0.3847) patients. Among stage III patients, we observed no difference in survival between stage IIIA and IIIB (p = 0.1914). In stage IIIA, patients classified as T3N2M0 had a significantly lower rate of survival (p = 0.0399). The presence of mediastinal ganglia in stage IIIB was associated with a lower survival rate (p = 0.0328). CONCLUSION: The new guidelines for staging non-small cell anaplastic lung carcinoma do not provide consistent prognoses for homogeneous groups of patients, at least not in certain categories.

Carcinoma, Bronchogenic↗
PubMed1999

[Resection of bronchogenic carcinoma invading the diaphragm].

The prognosis for survival when small cell non-anaplastic bronchogenic carcinoma (SCN-ABC) invades the diaphragm has not been clearly established because the diagnosis is rare. We report a series of eight patients who underwent full resection of SCN-ABC with diaphragm invasion. One died during the postoperative period. Mean survival was eight months for the remaining seven and no patient lived five years. All died as a result of remote metastasis. Given these results, we question whether surgery is the most appropriate treatment for these patients.

Aged↗
PubMed1999

[Application of selection criteria in sequential double lung transplantation].

Since the first sequential double lung transplant was performed in 1986, such procedures have been increasing in number and the criteria used as indications for this type of surgery have broadened. Our aim was to reflect on the application of selection criteria and to describe the anesthetic and surgical techniques and postoperative follow-up of 72 patients who underwent this type of transplant surgery between March 1993 and December 1998. Actuarial survival five years after surgery was 74.4%. Among patients requiring transplantation after septic disease, actuarial survival was 90.8% for cystic fibrosis and 88.2% for bronchiectasis. Of the preoperative risk factors analyzed (prior surgery, pachypleuritis, multiresistant germs, poor nutrition, mechanical ventilation and corticoid therapy), only prior treatment with high doses of corticoids proved significant. Eleven patients have been diagnosed of bronchiolitis obliterans, four have died and only two continue to experience difficulties in daily living. The high survival rate and the restriction-free life after recovery lead us to consider sequential double lung transplantation to be the treatment of choice for all pulmonary diseases.

Adult↗
PubMed1999

Antifungal prophylaxis during the early postoperative period of lung transplantation. Valencia Lung Transplant Group.

INTRODUCTION: Fungal infections occur frequently in lung transplant patients, with the highest risk being in the early postoperative period (the initial hospitalization after lung transplantation). Aspergillus is responsible for more than half of all fungal infections, and Aspergillus has even been considered a contraindication for lung transplantation because of its difficult therapy and frequently fatal outcome. The aim of this article is to evaluate the success of an antifungal prophylaxis protocol to prevent fungal infection in the immediate postoperative period in lung transplant recipients. MATERIAL AND METHODS: From March 1994 to March 1997, we performed 52 lung transplants in 31 men and 21 women who received antifungal prophylaxis with fluconazole, 400 mg/d, and aerosolized amphotericin B, 0.6 mg/kg/d, during the postoperative period. RESULTS: The mean (+/- SD) postoperative period duration was 49 +/- 27.5 days. No fungal infections were observed during this period, and all patients provided negative cultures. We also found no toxicity related to antifungal drugs. The dose of cyclosporine was easily adjusted in every recipient according to blood levels so that effective immunosuppression was not compromised. DISCUSSION: In our study, the removal of the lungs and antifungal prophylaxis with fluconazole and aerosolized amphotericin B prevented fungal infection in the postoperative period in all 52 lung transplant recipients.

Adolescent↗
PubMed1998

Removal of nitrate from industrial wastewaters in a pilot plant by nitrate-tolerant klebsiella oxytoca CECT 4460 and arthrobacter globiformis CECT 4500

Two strains, a gram-negative bacterium Klebsiella oxytoca CECT 4460 and a gram-positive, mycelium-forming bacterium Arthrobacter globiformis CECT 4500, tolerant to up to 1 M nitrate, were isolated from the grounds of a munitions factory. Under strict aerobic conditions and with appropriate C-sources, growth of these bacteria took place when the nitrate concentration in the medium was below 150 mM. Optimal growth conditions regarding the culture medium composition for the biological removal of nitrate were established in batch cultures. Then, the system was scaled up to a 40-L pilot plant and operated under continuous conditions in a factory with direct waste streams from dinitroethylene glycol production after appropriate dilution with nontreated groundwaters. The level of nitrate in the effluent was below 0.5% of the initial N-load. Nitrite and ammonium were undetectable and the level of the C-source in the effluent was below 50 mg per L. On the basis of these results, we conclude that the system worked on site satisfactorily. Copyright 1998 John Wiley & Sons, Inc.

Journal Article↗
PubMed1998

Identification and characterization of a new oncogene derived from the regulatory subunit of phosphoinositide 3-kinase.

p85/p110 phosphoinositide 3-kinase (PI3K) is a heterodimer composed of a p85-regulatory and a p110-catalytic subunit, which is involved in a variety of cellular responses including cytoskeletal organization, cell survival and proliferation. We describe here the cloning and characterization of p65-PI3K, a mutant of the regulatory subunit of PI3K, which includes the initial 571 residues of the wild type p85alpha-protein linked to a region conserved in the eph tyrosine kinase receptor family. We demonstrate that this mutation, obtained from a transformed cell, unlike previously engineered mutations of the regulatory subunit, induces the constitutive activation of PI3K and contributes to cellular transformation. This report links the PI3K enzyme to mammalian tumor development for the first time.

3T3 Cells↗
PubMed1997

Cot kinase regulation of IL-2 production in Jurkat T cells.

tpl-2 is a rat gene that encodes a serine/threonine protein kinase that can act as a novel mitogen-activated protein (MAP) kinase kinase kinase. Tpl-2 is activated in Moloney murine leukemia virus-induced rat T lymphomas, due to a truncation in the C-terminal region of the protein. cot is a very closely related gene, if not the human homologue. The truncated form of Cot has been shown to have a higher transforming activity than the nontruncated form. In this paper we show that an increase in truncated Cot kinase expression correlates with an increase in IL-2 production in anti-CD3-treated Jurkat cells. Truncated Cot expression also cooperates with PHA or phorbol 12,13-dibutyrate (PDBu) and calcium ionophore for IL-2 production in Jurkat cells. Both the truncated and nontruncated Cot forms increased IL-2 transcription because they enhanced transcription of a reporter gene linked to the IL-2 promoter. The expression of a dominant negative form of Cot inhibits transcription directed by the IL-2 promoter in Jurkat cells stimulated by PDBu and ionophore. These data suggest a role of Tpl-2/Cot kinase in IL-2 production during T lymphocyte activation and could also explain its role in Moloney murine leukemia virus-induced lymphomagenesis.

CD3 Complex↗
PubMed1997

[Reliability of the presurgical anatomopathologic diagnosis in primary bronchogenic carcinoma].

BACKGROUND: The specific cell type in primary lung cancer (LC) has important consequences, both for treatment and prognosis. Our objective has been to evaluate the degree of accuracy of several preoperative techniques in the LC diagnosis. PATIENTS AND METHODS: We have studied 442 diagnostic techniques realized in 360 patients who underwent thoracotomy for LC in our hospital (1988-1994). Twelve sputum cytologies, 93 transthoracic needle biopsies (TNB), 73 bronchial aspirated cytologies, 30 bronchial brushing, 205 bronchial biopsies (BB) and 29 transbronchial biopsies were included. In each case the cellular type of LC, obtained through these techniques, was compared with the result derived from the study of surgical piece (reference diagnosis). To calculate the degree of concordance between both diagnoses we used the kappa coefficient (K). RESULTS: The overall concordance between the cellular type observed in the different preoperative techniques and the definitive result obtained by thoracotomy was 0.61. The worst test was TNB (K = 0.41). Sputum cytology and BB presented a good histopathological precision (K = 0.75 and 0.70 respectively). The rest of techniques showed moderate results. On the different histologies, the best result was obtained in squamous carcinoma (K = 0.68) and the worst in undifferentiated large cell carcinoma (LCC) (K = 0.39). Small-cell lung cancer only showed a moderate concordance (K = 0.58). The coexistence and coincidence of two or more tests with the same cellular type were associated with a higher proportion of accuracy (0.97 vs 0.73; p = 0.00002; odds ratio: 12.02). CONCLUSIONS: The preoperative histopathological diagnoses should be interpreted with caution, especially those obtained by TNB and those where it is implied the LCC. In these two circumstances and in cases in which the knowledge of the cellular type have relevance, we think that the initial diagnosis should be reinforced with a second result. The precision of the preoperative diagnoses in small-cell lung cancer must be reevaluated.

Adenocarcinoma↗
PubMed1997

Surgical results and prognostic factors in early non-small cell lung cancer.

BACKGROUND: We attempted to clarify the prognostic value of tumor size (maximum, 3 cm), the evidence of invasion proximal to a lobar bronchus at least 2 cm distal to the carina, and the absence or presence of visceral pleura invasion in patients with completely resected non-small cell lung carcinoma without lymph node invasion or satellite lesions (T1 N0 M0, T2 N0 M0). METHODS: The study included 158 patients. Four patients were excluded due to postoperative mortality (2.5%). The variables selected for the survival study were sex, age, symptoms presence or absence, bronchial invasion level (evidence or not of invasion proximal to a lobar bronchus at least 2 cm distal to the carina), pulmonary location, pneumonectomy or lesser resection, cell type, squamous or nonsquamous, tumor size, invasion or not of the visceral pleura, and T1 or T2 status. RESULTS: The overall survival rate in this series was 74% at 5 years and 60% at 10 years. Only the tumor size had a significant influence on survival (p = 0.0092). Patients with a tumor less than 2 cm in diameter did better (p = 0.0023). CONCLUSIONS: These observations suggest that it will be necessary to further research in clarifying the prognostic value of the bronchial invasion level and of the degree of the visceral pleura invasion and its implications when classifying a tumor as T1 or T2.

Adult↗
PubMed1997

Antioxidants and AP-1 activation: a brief overview.

Activity of the transcription factor AP-1 is controlled by different MAPK cascades that regulate the different AP-1 components at the transcriptional and posttranscriptional level. Recently, AP-1 has been shown to behave as a redox-sensitive transcription factor that can be induced under both pro-oxidative and antioxidative conditions. In this overview we summarize the signaling pathways that converge on the activation of AP-1 and the components of these pathways that have been shown to be targets of antioxidants. The activation of AP-1 by antioxidants may account for the expression of a number of genes that mediate important functions under physiological conditions.

Antioxidants↗
PubMed1997

Removal of high concentrations of nitrate from industrial wastewaters by bacteria.

Klebsiella oxytoca isolate 15 was isolated from the grounds of a nitration factory and was found to be tolerant to nitrate at concentrations up to 0.5 to 1 M. Physicochemical parameters for optimal growth conditions for K. oxytoca isolate 15 were established. Growth took place when the nitrate concentration in the medium was less than 150 mM, and full nitrate consumption required about 14 g of C per g of N. This strain was able to remove nitrate without accumulating nitrite. The system was scaled up to a 40-liter pilot plant and was operated on-site satisfactorily.

Journal Article↗