PubMed Health⌕ Search

Biomedical subjects

C Cervera

Publications and source records attributed to C Cervera.

At least 55 records · Page 3Linked to original sources
PubMed1995

T cell receptor V alpha 4 is expressed by a subpopulation of V beta 6 T cells that respond to the bacterial superantigen staphylococcal enterotoxin B.

A subpopulation of murine minor lymphocyte-stimulating locus Ag (Mls)-1a-responsive, TCR V beta 6-expressing T hybrids was responsive to the superantigenic bacterial toxin, staphylococcal enterotoxin B (SEB), presented by murine MHC class II molecules. Comparative functional and surface marker analyses showed that this heterogeneity was not caused by nonspecific effects. It seemed, therefore, that the ability of the TCR V beta 6 T hybrids to respond to SEB was regulated by non-V beta TCR elements. cDNA sequencing analyses of the TCR beta- and alpha-chains expressed by the V beta 6 T hybrids and a beta-chain cDNA gene transfer experiment indicated that although J beta, CDR3 beta, J alpha, and CDR3 alpha were not the relevant elements, SEB responsiveness did correlate with the expression of two different members of the V alpha 4 family. A functional analysis of a separate panel of V alpha 4 T hybrids expressing different V beta elements, including V beta 6, specifically associated SEB responsiveness with the V alpha 4, V beta 6 combination. Overall, the data obtained with both panels of T hybrids showed SEB responsiveness in five out of five V beta 6, V alpha 4 T hybrids, and not in either 11 V beta 6 T hybrids expressing a variety of other V alpha elements or four V alpha 4 T hybrids expressing V beta 11, 14, and 15 elements. Thus, our experiments show for the first time a specific, positive qualitative effect of a defined V alpha element on responsiveness to a bacterial superantigen. Finally, this study has identified four new V alpha elements.

Amino Acid Sequence↗
PubMed1995

[Postoperative lesions of the peripheral nerves. 8 years' analysis].

Damage to a plexus or peripheral nerve is a rare and avoidable complication of surgical anesthesia. We reviewed 2,750 case histories of patients who underwent surgery between 1985 and 1992, finding 6 cases of nerve lesions presenting postoperatively. Sequelae involved 1 abdomino-genital neuralgia, 1 case of post-epidural radicular pain, 2 cases of peroneal nerve palsies and 2 of cubital paresis. Three of these cases were related to position during surgery, 1 to position during a prolonged period in bed in the intensive care unit, 1 to the anesthetic technique and 1 to surgical manipulation. Our data are important given the difficulty of studying the incidence of such cases due to patient dispersion and the loss of records of possible occurrences. The mechanisms by which lesions are produced are sometimes difficult to pinpoint but all are generally preventable.

Aged↗
PubMed1994

Posterior fossa reconstruction: a surgical technique for the treatment of Chiari I malformation and Chiari I/syringomyelia complex--preliminary results and magnetic resonance imaging quantitative assessment of hindbrain migration.

Experimental models have shown that Chiari I malformation is a primary paraaxial mesodermal insufficiency occurring after the closure of the neural folds takes place. According to these hypotheses, a small posterior fossa caused by an underdeveloped occipital bone would be the primary factor in the formation of the hindbrain hernia. The main objective in the surgical treatment of Chiari I malformation and related syringomyelia is directed to restore normal cerebrospinal fluid dynamics at the craniovertebral junction. The most widely accepted surgical approach is to perform a craniovertebral decompression of the posterior fossa contents with or without a dural graft. It has been emphasized that suboccipital craniectomy should be small enough to avoid downward migration of the hindbrain into the craniectomy. This slump of the hindbrain has been verified by studies using postoperative assessment by magnetic resonance imaging. Our aim in this study is to present a modification of the conventional surgical technique, which we have called posterior fossa reconstruction (PFR). Ten patients were operated on using this technique and compared with a historical control group operated on with the classic approach of making a small suboccipital craniectomy, opening the arachnoid, and closing the dura with a graft. To evaluate the morphological results in both groups objectively, preoperative and postoperative measurements of the relative positions of the fastigium and upper pons above a basal line in the midsagittal T1-weighted magnetic resonance images were obtained. In those cases with syringomyelia, syringo-to-cord ratios were calculated. The mean age of the PFR group was 35 +/- 16 years (mean +/- SD); in the control group it was 35.2 +/- 12 years. In the PFR group, the formation of an artificial cisterna magna was observed in every case; it was observed in only one case in the control group. An upward migration of the cerebellum was seen in all cases in the PFR group, with a mean ascent of the fastigium of 6.2 mm. A significant downward migration of the cerebellum was observed in seven cases in the control group. No significant differences were found in both groups when comparing syringo-to-cord ratios. This leads us to conclude that PFR is more effective than conventional surgical approaches in restoring the normal morphology of the craniovertebral junction. This allows cranial ascent of the hindbrain verified by magnetic resonance imaging and good short-term clinical results. Because PFR is mainly an extraarachnoidal approach, complications related to surgery using this technique can be kept to a minimum.

Adult↗
PubMed1992

[Initial otorhinolaryngologic lesions of lepromatous leprosy].

The paper deals with a topic rarely treated in the bibliography: a carrier of cutaneous and otolaryngologic lesions suspicious of lepromatous leprosy. The AA. made a survey of the typical ENT manifestations of the generalized disease--lepromatous leprosy--and recall the more characteristic diagnostic tests as well as the guide lines of the treatment.

Adult↗
PubMed1990

Skin biopsy findings in glycogenosis III: clinical, biochemical, and electrophysiological correlations.

Electron microscopy of skin specimens was performed in 4 patients (age range, 7 months-40 years) with glycogenosis III and revealed consistent abnormalities. Massive glycogen storage was observed in epithelial secretory cells of eccrine sweat glands and, less markedly, in smooth muscle fibers from the erector pili. Other cells, including Schwann cells of myelinated and unmyelinated fibers, were not affected. The extent of glycogen storage was similar in all patients and unrelated to age or duration of disease. The extralysosomal nature and selectivity of glycogen deposits, sparing fibroblasts and other cells, differ clearly from the findings in skin from patients with glycogenosis II. The purpose of this study was to show that glycogen deposits in glycogenosis III are not restricted to skeletal muscle and liver, and to assess the usefulness of skin biopsy in this disorder.

Adolescent↗
PubMed1989

[Nuclear resonance in intracranial venous thrombosis].

We have reviewed the nuclear resonance NR images in three patients with intracranial venous thrombosis. Tomodensitometric findings are not reliable in intracranial venous thrombosis and cerebral angiography is required for the diagnosis. The usefulness of NR for the investigation of venous disease has been recently demonstrated. Ten patients in whom a diagnosis of intracranial venous thrombosis was made with NR have been reported. Initially, the vacuum signal in the T1 enhanced sequences disappears and the thrombus becomes hypointense in the T2 enhanced sequences. In the following phase, proton relaxation is impaired by methemoglobin production and thrombosis appears as hyperintense in both the T1 and T2 enhanced sequences. During the resolution phase, the vacuum signal in the vascular lumen reappears and the hyperintensity of the thrombus signal becomes attenuated. In our study we have shown the different stages of intracranial venous thrombosis with NR. In addition, we have demonstrated the close relation between these images and the clinical evolution. NR is a useful noninvasive investigation in patients with suspected intracranial venous thrombosis.

Aged↗