Medial pallidotomy in late-stage Parkinson's disease and striatonigral degeneration.
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Globus Pallidus↗
Biomedical subjects
A Lozano
Publications and source records attributed to A Lozano.
[Quality in medication prescription and evidence-based medicine].
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Drug Prescriptions↗
[Laboratory diagnosis of subacute and acute encephalitis probably of viral origin: seven years of experience].
The results obtained in the laboratory diagnosis of 609 cases of acute or subacute encephalitis, studied during a period of time of even years, is briefly presented. Diagnostic methods included virus isolation from stools and cerebrospinal fluid (CSF); specific serology in serum; detection of intrathecal production of IgG antibody; and, in the last two years, detection of viral genome sequences in CSF by the polymerase chain reaction. Significant results were obtained in 196 cases (32.2%) and the alfa-herpesviruses were responsible for a major part of them (77.5%). Furthermore, 18 cases were likely to respond to dual infection by both herpes simplex and varicella-zoster viruses. Epstein-Barr virus and Human herpesvirus 6 were found in CSF from three immunocompetent patients. Besides the current vaccination program, measles virus is still responsible for an important part (22/196, 11.2%) of cases of viral encephalitis.
Acute Disease↗
Oestrogens and depression.
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Depressive Disorder↗
Human central nervous system myelin inhibits neurite outgrowth.
In vitro and animal studies have identified molecules in mammalian CNS myelin which inhibit neuritic extension and which may be responsible, at least in part, for the lack of axonal regeneration after injury in the injured brain, optic nerve and spinal cord. To determine whether such inhibitory activity may be present in human CNS myelin, we used a bioassay to characterize neurite outgrowth on this substrate. Human CNS myelin strongly inhibited neuritic outgrowth from newborn rat dorsal root ganglion neurons and NG-108-15 cells, a neuroblastoma-glioma hybrid cell line. Similar but less potent inhibitory activity was identified in human gray matter. The CNS myelin inhibition of neuritic outgrowth appeared to be dependent on direct contact between the myelin substrate and neurites. The inhibitory activity in human CNS myelin closely resembled that described in adult rodents. Inhibition of neurite growth by human CNS myelin in this in vitro bioassay mirrors the lack of regeneration in vivo and can be used as a model to develop strategies designed to enhance axonal regeneration and neural recovery.
Aged↗
Myelin from MAG-deficient mice is a strong inhibitor of neurite outgrowth.
Myelin-associated glycoprotein (MAG) has potent neurite outgrowth inhibitory activity in vitro. To assess the importance of MAG in the neurite outgrowth inhibitory activity in CNS myelin, we used an in vitro bioassay to characterize neurite growth on CNS myelin derived from mice carrying a null mutation of the MAG gene. Myelin proteins from MAG-deficient mice inhibited neurite outgrowth to a similar degree to the wild-type CNS myelin. These results suggest that CNS myelin molecules other than MAG exert strong inhibitory effects on the growth of neurites.
Animals↗
Detection of both herpes simplex and varicella-zoster viruses in cerebrospinal fluid from patients with encephalitis.
Cerebrospinal fluid (CSF) samples from 46 patients with encephalitis were studied for the presence of herpes simplex virus (HSV) types 1 and 2 and/or varicella zoster virus (VZV)-specific DNA sequences by the polymerase chain reaction (PCR) assay. Patients were studied because of detection of intrathecal production of IgG antibody to HSV alone (10 patients, Group A) or to both HSV and VZV (11 patients, Group B) or because of the presence of specific anti-HSV IgG in CSF without evidence of intrathecal antibody production (25 patients, Group C). CSF samples taken between days 1 and 10 from onset of encephalitis were available from all patients, and follow-up samples (taken after 10 days from onset) were obtained from some of them. Positive PCR results were obtained in a total of 13 patients. Four patients (three from Group A and one from Group B) gave amplification of HSV type 1 DNA alone, two patients (both from Group B) showed amplification of VZV DNA alone, and seven patients (all from Group B) gave dual amplification of both HSV type 1 and VZV DNA sequences in CSF. All CSF samples from patients in Group C were negative by PCR. Ten patients with CSF samples positive by PCR lacked a prior history of herpetic cutaneous lesions. In seven patients, serum antibody tests (specific IgM detection and specific IgG avidity assays) identified both primary and recurrent infections. The results suggest that the dual presence of IgG antibody to both HSV and VZV in CSF from patients with encephalitis may reflect in some cases a dual infection of the central nervous system caused by both agents.
Adult↗
The safety and effectiveness of stepwise and low-dose administration of follicle stimulating hormone in WHO group II anovulatory infertile women: evidence from a large multicenter study in Spain.
PURPOSE: Our goal was to investigate the safety, effectiveness, and feasibility for the practicing physician of stepwise and low-dose administration of FSH in WHO group II anovulatory infertile women. METHODS: Infertile female patients (n = 234) suffering from WHO group II anovulation, and who failed to became pregnant with clomiphene citrate, were included in a multicenter, prospective, clinical study of treatment with a protocol of chronic low-dose and small incremental rises with urinary purified or highly purified FSH. Follicular development was monitored with ultrasonographic scans. RESULTS: The 234 patients received a total of 534 cycles of treatment, for a mean number of 2.3 treated cycles per patient. hCG was withheld in 65 (12.2%) cyles because of no response and in 28 (5.2%) cycles because of hyperresponse. Of the remaining 441 cycles, 419 (95%) were ovulatory, and in 198 (47.3%) of these cycles a single dominant follicle developed. There were 93 pregnancies (39.7% per patient), for a cycle fecundity rate of 17.4%. Cumulative conception rate after two treated cycles was 33.5%. There were 14 (15%) pairs of twins and 10 (10.8%) spontaneous miscarriages. The prevalence of complications was low with no cases of severe OHSS. Basal LH/FSH ratio was significantly higher in the pregnant group of patients than in nonpregnant women. CONCLUSIONS: Stepwise and chronic low-dose administration of FSH is a safe and effective method for treatment of WHO group II anovulatory infertility, mainly in those patients having high LH/FSH ratios.
Adult↗
Abscess within a brain metastasis.
BACKGROUND: Neoplastic metastases to the cerebellum are a frequent complication in patients with carcinoma. However, the co-existence of an abscess within a CNS metastasis is a rare event. METHODS: We report the case of a 79-year-old woman with two cerebellar abscesses within metastatic lesions in the cerebellum. She presented with a rapidly progressing syndrome characterized by elevated intracranial pressure and cerebellar findings. RESULTS: At surgery, a purulent exudate within discrete metastatic tumours was identified. Pathological and microbiological examinations confirmed the coexistence of an abscess within a metastatic carcinoma. SIGNIFICANCE AND CONCLUSION: The radiological diagnosis o f intracranial abscesses and metastases can be non-specific and brain imaging may not reliably identify both processes when they coexist. Furthermore, brain metastases often contain liquefied material which can be mistaken for tissue necrosis rather than an infectious process. It is important to be aware that a brain metastasis can also be infected. Therefore, acquisition of lesional tissue for both pathological and microbiological examinations is essential for accurate diagnosis and to direct optimal therapy in situations where the intracranial lesion could be either an abscess or a metastatic deposit.
Aged↗
A parallel broadband real-time system for electrical impedance tomography.
This paper deals with the design, implementation and performance of TIE-4sys, an electrical impedance tomograph. This instrument is a parallel broad-band real-time system. It measures impedance using an array of 16 electrodes and reconstructs the images using a weighted back-projection technique. The objective of this development is to enable multifrequency EIT clinical studies to be undertaken. The system is capable of acquiring 25 frames/s and makes multifrequency cardiac-gated images. The frequency range is from 10 kHz to 250 kHz and the signal to noise ratio for the real component is better than 60 dB.
Electric Impedance↗
Hemiballism in Parkinson's disease.
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Basal Ganglia↗
Methods for microelectrode-guided posteroventral pallidotomy.
Methods for localizing the posteroventral globus pallidus intermus are described. The authors' techniques include the use of microelectrodes to record single-unit activity and to microstimulate in human pallidum and its surrounding structures. This technique allows a precise determination of the locations of characteristic cell types in sequential trajectories through the external and internal segments of the pallidum. The location of the optic tract can be determined from microstimulation-evoked visual sensations and recordings of flash-evoked potentials. In addition, microstimulation-evoked motor and sensory responses allow the internal capsule to be identified. The data collected using this technique are an important adjunct to selecting optimum sites to place electrocoagulation lesions for stereotactic posteroventral pallidotomy for refractory Parkinson's disease.
Catheter Ablation↗
[Dysphagia as an unusual form of presentation of malignant pleural mesothelioma].
Dysphagia is an unusual presenting symptom as of extradigestive tumors. Malignant mesothelioma, is a rare tumor localized in the pleural cavity in 80% of all cases and it rarely appears with dysphagia as first symptom. We describe the case of a 74-year-old woman admitted with progressive dysphagia for solid and liquid food, atypical epigastric pain, with in conclusive endoscopic and radiologic studies. Nuclear Magnetic Resonance established the diagnostic suspicion of malignant mesothelioma which was confirmed by the histologic study of a biopsy taken by thoracotomy. We think of interest to report this case of paraesophageal mesothelioma because of its unusual localization and presentation.
Aged↗
Multi-frequency static imaging in electrical impedance tomography: Part 1. Instrumentation requirements.
Static images of the human body using electrical impedance tomography techniques can be obtained by measuring at two or more different frequencies. The frequencies used depend on the application, and their selection depends on the frequency behaviour of the impedance for the target tissue. An analysis using available data and theoretical models for tissue impedance yields the expected impedance and boundary voltage changes, therefore setting the measurement instrument specifications. The instrument errors produced by different sources are analysed, and, from this analysis it is possible to determine the feasibility of building the instrument, the limit values for some parameters (or components) and indications on the most suitable design of critical parts. This analysis also shows what kinds of error can be expected in the reconstructed images. It is concluded that it is possible to build an instrument with limited errors, allowing static images to be obtained. An instrument has been built that meets some of the design requirements and fails in others because of technological problems. In vivo images obtained with this instrument will be presented in Part 2 of this work.
Electric Impedance↗
Errors in prolonged electrical impedance measurements due to electrode repositioning and postural changes.
Long-term electrical impedance measurements are affected by specific errors. Electrode failure, changes in its impedance due to aging, and postural changes are among the most important. We analyse errors due to electrode replacement and body postural changes. Electrode replacement errors can cause impedance changes up to 5% of basal value. This is one of the most important factors in data reproducibility. Body postural changes also contribute to impedance variations. We have proposed the use of a reference position to carry out impedance measurements as the one that shows the smallest impedance sensitivity to postural changes. In general, we observed that this is achieved with arms and legs slightly separated from the body. We propose the use of a ratio of impedance at two different frequencies to discern the origin of impedance changes, whether from physiological phenomena or postural errors.
Adult↗
A multifrequency multichannel electrical impedance data acquisition system for body fluid shift monitoring.
This paper discusses some important issues for the design of electrical impedance measurement systems intended for body fluid shift monitoring, in particular during dialysis treatments. We have studied two common signal generation systems: digital synthesis and carrier recovery. We have found that in prolonged measurement applications, digital synthesis yields the best performance. On the demodulation side, we balance the demodulator errors between the real and imaginary parts by rotating the demodulation axes. We use segmental multifrequency impedance measurements to estimate the values of intracellular and extracellular impedance by adjusting the parameters of a Cole-Cole model for each segment measured. We stress the need to perform segmental measurements in order to accurately measure the segments of interest, in particular the trunk during dialysis treatments. Our results show that there is a sharp disequilibrium between the intracellular and extracellular compartments in the very first dialysis period. This fact generates the need to continuously measure segmental impedance instead of comparing initial and final values.
Body Fluid Compartments↗
Failed stereotactic biopsy in a series of 518 cases.
Failed stereotactic biopsy is one in which a definitive histological or microbiological diagnosis is not achieved based on the tissue obtained. Of 518 consecutive CT-guided stereotactic biopsies of intra-axial mass lesions, 42 (8.1%) cases were failed biopsies. Inflammatory changes were seen in 10 cases (24%); gliosis was seen in 11 cases (26%); 9 cases (21%) yielded necrotic specimens; normal brain was retrieved in 7 cases (17%); blood/hemorrhagic brain was seen in 3 cases and in 2 cases, no tissue could be obtained. Variables that significantly influenced the diagnostic success included the immune status (HIV positive; p < 0.001). The complication rate in the failed biopsy group was significantly higher. The subsequent management and outcome of patients who suffered a failed stereotactic biopsy are discussed.
Adolescent↗
Thalamotomy for essential and cerebellar tremor.
Thalamotomy significantly suppressed essential tremor in 86% of patients and restored the ability to hold a glass to drink in 81% in the long term, but tremor recurred in 5/21 patients up to 5 years postoperatively, unlike parkinsonian patients whose tremor seldom recurs after 3 months. In multiple sclerosis (MS), 67% of those followed showed sustained significant suppression of tremor, 67% sustained improvement in dexterity, 50% in drinking; tremor recurred up to 5 years postoperatively. In other cerebellar tremors, 52% of those followed enjoyed lasting significant relief of tremor, 55% in dexterity, 45% in drinking, tremor relief being best in poststroke cases. Chronic thalamic stimulation may be the preferred therapy in MS and other cerebellar tremors.
Adult↗