Search PubMed⌕ Search

Biomedical subjects

R Casas

Publications and source records attributed to R Casas.

30 records · Page 2Linked to original sources
PubMed1994

Parvalbumin and calbindin-D28k immunocytochemistry in human neocortical epileptic foci.

Serial sections of cortical resection of 30 patients suffering from drug-resistant epilepsy were processed for parvalbumin and calbindin-D28k immunocytochemistry to determine local circuit neuron populations. Our findings indicate that there is not a simple mechanism to explain neocortical epileptic foci. On the basis of the present results it can be suggested that: (1) reduced percentage of local circuit neurons in the vicinity of neoplasms may account for a decreased intracortical inhibition. (2) Abnormal morphology and distribution of local circuit neurons may result in abnormal cortical inhibition in patients with focal cortical dysplasia, and, probably, in other focal migrational disorders, including neuronal nests in the white matter. (3) Increased percentages of immunoreactive local circuit neurons and fibers in focal neocortical necrosis (cavernous angiomas), diffuse hypoxic encephalopathy, and hippocampus in patients with temporal lobe epilepsy due to mesial sclerosis, may play a role in epilepsy. These neurons can be activated by reduced excitatory inputs, or they may establish abnormal synaptic contacts with other inhibitory neurons. (4) Lack of consistent morphologic abnormalities in the neocortex of patients with temporal lobe epilepsy, and in patients with cryptogenetic frontal lobe epilepsy, suggests that electrically abnormal neocortical foci in these cases are probably epiphenomena.

Adolescent↗
PubMed1993

Parvalbumin-immunoreactive dystrophic neurites and aberrant sprouts in the cerebral cortex of patients with Alzheimer's disease.

Parvalbumin-immunoreactive dystrophic neurites and aberrant terminal sprouts associated with senile plaques, together with preserved density of parvalbumin-immunoreactive neurons, were found in the cerebral cortex of two patients with Alzheimer's disease, one of them familiar, in which a biopsy of the left frontal lobe was carried out for diagnostic and counselling purposes. These findings suggest that, although parvalbumin-immunoreactive cells are relatively resistant to degeneration in Alzheimer's disease, parvalbumin-immunoreactive neuronal processes can degenerate in some cases of Alzheimer's disease.

Aged↗
PubMed1993

Parvalbumin-immunoreactive cortical neurons in Creutzfeldt-Jakob disease.

Massive abnormalities of parvalbumin-immunoreactive cortical neurons were observed in the cerebral biopsy samples of 3 patients with Creutzfeldt-Jakob disease. Immunoreactive cells had reduced and short, often fragmented, dendrites, and large numbers of dendritic varicosities were observed. Since parvalbumin-immunoreactive neurons are the most important inhibitory cells in the cerebral cortex, the damage to these neurons may account, in part, for the impaired cortical function, and may play a role in the appearance of myoclonus and electroencephalographic patterns in patients with Creutzfeldt-Jakob disease.

Cerebral Cortex↗
PubMed1993

Healthy children's understanding of their blood: implications for explaining leukaemia to children.

Explanations of leukaemia to children usually include details of blood function and structure. In study 1, 3-year-olds (N = 25), 4-year-olds (N = 25), and 8-year-olds (N = 27) were interviewed about their understanding of the properties of blood and any occasions when they remembered seeing blood. They were also asked whether other animals and objects had blood or not, and to give reasons for this. Children justified their decisions in three ways: only people have blood, they had seen blood on a particular occasion, or only creatures which shared a human property (walking or talking) could have blood. In study 2, an intervention to increase children's understanding of the function of different blood cells is reported. It was partially successful. Children who reported an incident in which they saw blood were more likely to recall information about the function of red cells, white cells and platelets compared with children who did not report a previous experience (p < .001). In terms of explaining leukaemia to a child, we conclude that explanations should build on previous experience, and not be based simply on chronological age.

Blood↗
PubMed1993

Calbindin D-28k and parvalbumin immunoreactivity in the frontal cortex in patients with frontal lobe dementia of non-Alzheimer type associated with amyotrophic lateral sclerosis.

The morphology and distribution of local-circuit neurons (interneurons) were examined, by calbindin D-28k and parvalbumin immunocytochemistry, in the frontal cortex (area 8) in two patients with frontal lobe dementia of non-Alzheimer type associated with classical amyotrophic lateral sclerosis (ALS), and in seven normal cases. The density of calbindin D-28k immunoreactive cells was dramatically reduced in ALS patients, but the density of parvalbumin-immunoreactive neurons was preserved. Decreased density of calbindin D-28k-immunoreactive neurons, which are mainly located in the upper cortical layers, may interfere with the normal processing of cortico-cortical connections, whereas integrity of parvalbumin-immunoreactive cells may be associated with the preservation of the major inhibitory intracortical circuits in patients with frontal lobe dementia.

Adult↗
PubMed1993

Multiple atypical bone involvement in sarcoidosis.

We describe a patient with right paratracheal and left hilar lymph nodes detected by chance on chest radiography that followed a spontaneous remission. However, a few months later she complained of multiple scalp nodules. Skull roentgenogram and computerized tomogram scan showed multiple osteolytic lesions with increased uptake in bone and gallium scans. Lytic lesions were also detected in her right mandibular bone and right clavicle. Noncaseating granulomas were demonstrated in skull and cervical lymph node biopsies.

Bone Diseases↗
PubMedDate not supplied

A prospective and multicenter safety-monitoring study of a short up-dosing schedule of immunotherapy with a mass-units-standardized extract of mites.

A prospective, multicenter pharmacovigilance study was carried out to evaluate the safety of a new 7-dose treatment schedule of subcutaneous immunotherapy as opposed to the conventional 13 doses normally recommended. The study was carried out in 14 centers and included 261 patients (children and adults) with respiratory allergic disease due to sensitization to mites (Dermatophagoides pteronyssinus and/or farinae). A total of 2290 doses were administered under the direct supervision of the participating specialists. One hundred and ten reactions in 63 patients (24.1%) were recorded, representing 4.8% of the total doses administered. Most of the reactions (98) were local. Only 12 were systemic (0.5% of the administered doses) and occurred in 10 patients (3.8% of the sample). Ten reactions reverted quickly with rescue medication. The maintenance dose had to be lowered in one patient and another patient was withdrawn from the study after suffering two asthmatic crises after two consecutive doses. In view of the results obtained, we can conclude that the new schedule shows an acceptable tolerance profile and does not present a greater risk of reactions than the conventional scheme of 13 doses using an identical extract. Moreover, the new schedule represents substantial savings in the number of doses and visits required to reach the maintenance dose.

Adult↗
PubMedDate not supplied

Blood recirculation in malfunctioning catheters for haemodialysis.

Venous catheters are increasingly used for chronic haemodialysis, with dual lumen catheters being the most commonly used as blood recirculation (REC%) is relatively low. The aim of this study was therefore to evaluate blood recirculation in dual lumen catheters, both well-functioning and malfunctioning, with reversed lumens. In our study, blood recirculation in well-functioning catheters with standard lumens is similar to that found in previous studies. However, when lumens are reversed, blood recirculation increases significantly (6.7 +/- 4 vs 19 +/- 11%, p < 0.001). REC% in malfunctioning catheters (10.8 +/- 2%) was higher than normal function (p < 0.05) but lower than reversed flow in normal catheters (p < 0.01). Therefore, inadvertent reversal of lumens in a well-functioning catheter increases REC% in a significant manner, thus worsening haemodialysis efficiency. We conclude that, in inflow failure catheters, lumens can be reversed because REC% is acceptable. However, inadvertent reversal of lumens in a well-functioning catheter increases REC% to a level which may compromise the adequacy of haemodialysis.

Blood Circulation↗
PubMedDate not supplied

Atopic dermatitis today.

This review focuses on recent literature regarding atopic dermatitis (AD). New insights in epidemiology, diagnostic criteria, quality of life measures, provocative factors, patophysiology and therapy will be highlighted. New diagnostic criteria for AD set by the UK working party allow easier epidemiologic studies to cope with this increasingly prevalent disease. Immunomodulating therapy with cyclosporine holds promise in the treatment of refractory AD.

Adolescent↗