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Biomedical subjects

M Pérez-Alvarez

Publications and source records attributed to M Pérez-Alvarez.

9 recordsLinked to original sources
PubMed2006

The role of meta-cognitions and thought control techniques in predisposition to auditory and visual hallucinations.

OBJECTIVES: This study examines the relationship between a predisposition to hallucinations and meta-cognitive variables and thought-control techniques, controlling for the possible effect of anxiety. In order to do so, we start out with the hypothesis that anxiety does not, in itself, explain the association between meta-cognitions and a predisposition to auditory and visual hallucinations. DESIGN: A within-participants correlational design was employed. METHODS: Four psychometric tests relating to predisposition to hallucinations, anxiety, meta-cognitions and thought-control techniques were administered to 150 participants. RESULTS: It was found that, after controlling for participants' anxiety levels, the 'loss of cognitive confidence' factor predicted the score on the scale of predisposition to both auditory and visual hallucinations. Thought-control strategies based on worry were also found to be predictive of a greater predisposition to hallucinations, regardless of whether or not participants' anxiety level was controlled. CONCLUSIONS: Meta-cognitive variables of cognitive confidence and thought control through worry are positively associated with a predisposition to hallucinations. LIMITATIONS: The correlational nature of the design does not allow inferences about causal relationships.

Adult↗
PubMed2005

Graphite-incorporated MoS2 nanotubes: a new coaxial binary system.

Graphite-filled MoS2 nanotubes were synthesized by pyrolizing propylene inside MoS2 nanotubes prepared by a template-assisted technique. The large coaxial nanotubes were constituted of graphite sheets inserted between the MoS2 layers, forming the outer part, and coaxial multiwall carbon nanotubes intercalated with MoS2 inside. High-resolution electron microscopy (HREM) and electron energy loss spectroscopy techniques along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nanotubes with several structural irregularities. The interplanar spacing between the MoS2 layers was found to increase from 6.3 to 7.4 A due to intercalation with carbon. Simulated HREM images revealed the presence of mechanical strains in the carbon-intercalated MoS2 layers as the reason for obtaining these twisted nanostructures. The mechanism of formation of carbon-intercalated MoS2 tubular structures and their stability and electronic properties are discussed. Our results open up the possibility of using MoS2 nanotubes as templates for the synthesis of new one-dimensional binary-phase systems.

Journal Article↗
PubMed2001

[Design, implementation, and results of the clinical pathway for herniated lumbar disk].

INTRODUCTION: Clinical or critical pathways are a useful tool in the continuous quality improvement. They develop the main characteristics of the quality programs: implementation of the evidence based medicine, increase staff and patient satisfaction and adequacy in hospital costs. This is the application of evidence-based medicine to a process management and it promotes integration of clinical guides, protocols and algorithms. OBJECTIVE: We present our experience in the design, and first nine month's implementation and development of a clinical pathway for lumbar hemilaminectomy. PATIENTS AND METHODS: This clinical pathway consists on four documents: main guide and check sheet, preprinted treatment orders and variation sheet, iconographic information for the patients and patient satisfaction questionnaire. After desing, development and a pilot study, the hemilaminectomy critical pathway was permanently adopted by our Service. A total of 106 patients underwent programmed lumbar disc hemilaminectomy in our Service between April and December-1999. Patients' average age was 44.7 years (SD = 11.2), 55.3% were men and 43.7% women. Twelve were hospitalized in a ward other than Neurosurgery unit and therefore were excluded from the study. This evaluation is based on the initial results obtained from both the pathway documents and the general data collected as usual during hospital care. The impact of the critical pathway on hospital stay has been assessed by comparing the average stay of critical pathway patients to the average of the 70 hemilaminectomies performed at our Service in the period April-December 1998. RESULTS: Clinical pathway coverage has been 68% (standard > 80%). The patients' average stay was 4 days (SD = 1.1), one day more than planned. The pathway establishes a 4 day hospital stay (3 bed-days), a time that was fulfilled by 49% of the patients. The average stay of the 1998 patients was 5.6 days (SD = 2.7), 1.6 days more than the clinical pathway patients (p < 0.0001). Additionally, undesirable variability in the length of hospital stays was also reduced. Analysis of variations identified those corresponding to patient's condition, increases in medication beyond that originally specified due to patient needs, and unjustified prolonged stays. There were no systematic variations. There was a 2.2% incidence of adverse effects. Although satisfaction questionnaire was only returned by 51% of the patients (instead of > 70%), satisfaction index were 93% (vs 90%). CONCLUSIONS: Critical pathways are still under development and changing continuously. Nevertheless their impact on improving patient care and satisfaction, and resource consumption is already evident, and it constitutes a major aim to work in its complete development.

Adolescent↗
PubMed2001

[Efficacy of arthrodesis in the posterior approach of cervical myelopathy: comparative study of a series of 36 cases].

OBJECTIVE: The effectiveness of arthrodesis associated to laminectomy as a treatment for cervical myelopathy has been retrospectively evaluated analysing the clinical evolution of 36 patients as well as the change in cervical column saggittal curvature comparing a group of patients with a simple laminectomy to another in whom laminectomy was accompanied by posterior arthrodesis. MATERIAL AND METHODS: 36 posterior approaches were performed to treat patients diagnosed of spondyloartrosic myelopathy between 1992 and 1999; 19 cases were treated with a simple laminectomy and other 17 also underwent arthrodesis with posterior instrumentation. The clinical evolution (using grades 0-5 on the Nurick scale) and cervical curvature have been evaluated for an average time interval of 40 months. RESULTS: Patients treated with laminectomy plus arthrodesis showed an average 1.24 point improvement on the Nurick scale in comparison to the 0.84 point improvement observed in patients treated with laminectomy alone. The cervical curvature attained a more physiological angulation in 53% of the patients with an arthrodesis and in 29% of the patients with simple laminectomy; curvature worsened in 7% of the patients with arthrodesis and in 24 degrees/a of those with laminectomy alone. CONCLUSION: Cervical myelopathy cases requiring a posterior approach for laminectomy obtain a better clinical evolution when an arthrodesis with posterior instrumentation is associated with the laminectomy. These patients also present improved cervical curvature as compared to the group without instrumentation.

Adult↗
PubMed1983

Posterior fossa epidural hematomas: a review and synthesis.

The authors report three patients with posterior fossa epidural hematomas and analyze 80 additional cases in the accessible literature. They occur in the younger age groups with a clear male predominance (3.6 to 1). The loss of consciousness at the time of impact and just before surgical intervention have both proved to be factors indicating a poor prognosis. The clinical symptoms and signs were classified in three general types: increased intracranial pressure, brainstem dysfunction, and cerebellar disturbances. A fracture of the occipital bone was seen in 84.2% of the patients. The source of bleeding often remained undetermined, although a tear of the dural sinuses was a most frequent finding. An associated intracranial lesion was found in 39.7% of the cases, this being another factor indicating a poor prognosis. The overall mortality was 26.5%, while the surgical mortality was only 11.5%. Excellent results were achieved in 65% of the cases.

Brain Injuries↗
PubMedDate not supplied

[Protective effects of growth hormone en cell cultures of the central nervous system].

OBJECTIVE: We examine a possible protective effect from growth hormone (GH) against radiation in cell cultures of rat embryon brain cortex. MATERIALS AND METHODS: Brain cortexes were removed from rat embryos of 17 days development and prepared for cell culture. The culture medium of half the plates was enriched with 500 ng/ml GH. All plates received a radiation dose of 3 Gy per plate and were again incubated for 24 hours. The TUNEL technique was employed to verify cell apoptosis in the irradiated plates and compare its level in plates with and without GH. CONCLUSIONS: We observed that irradiated cultures with GH had significantly less cell apoptosis than those without GH and concluded that this hormone excercised a protective effect on the cell cultures. The present study demonstrated the protective effect from GH in rat embryonary cells and suggests the need for future in vitro and in vivo studies using central nervous system cells.

Animals↗
PubMedDate not supplied

[Update in neurocysticercosis treatment].

INTRODUCTION: Neurocysticercosis is the most frequent central nervous system parasitosis, although quite infrequent in our country. Its rising incidence can be explained by immigration from regions of the world where this disease is endemic. OBJECTIVE: This paper reviews treatment options for this condition. PATIENTS AND METHODS. Eight patients have been diagnosed with neurocysticercosis in the last three years in our hospital. Patient age, sex, origin, symptoms, CT and MR images, diagnostic tests, treatment and duration of medical treatment and clinical and neuroradiological evolution are examined. RESULTS: Patient age ranged from 25 to 33 years, all eight came from South America and the most frequent initial symptom was an epileptic crisis. Two patients had a single lesion, six had multiple lesions and all eight showed the lesion in the parenchyma. Only 50% showed a positive serum ELISA test for Taenia solium. Initial treatment was surgical in only one patient and the other seven received albendazol. In one of the latter the drug was ineffective and surgery was undertaken. A ten month follow up period has found a favorable evolution in all the patients, who are all also asymptomatic at the present time. DISCUSSION AND CONCLUSIONS: Neurocysticercosis is more common among immigrants than the local population in Spain. The initial treatment should be medical, with surgery as an option for non responders. We believe that duration of the medical treatment will depend on the patient and the clinico radiological evolution of his/her disease.

Acute Disease↗
PubMedDate not supplied

[A comparative study of the treatment of high grade gliomas].

INTRODUCTION: The influence of surgery, radiotherapy and/or chemotherapy on the outcome on the results in patients with malignant gliomas is controversial. PATIENTS AND METHODS: We studied 44 patients (26, women; 18 men; age 38 72 years) diagnosed with grades III and IV astrocytoma who had been operated and then received adjuvant radiotherapy and either BCNU or temozolamyde chemotherapy. Survival time and adverse effects of the chemotherapy were analysed. CONCLUSION: Aggressive surgery associated with radiotherapy and temozolamyde chemotherapy prolonged survival in our patients with malignant astrocytomas.

Adult↗