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Biomedical subjects

J Barberá

Publications and source records attributed to J Barberá.

At least 19 recordsLinked to original sources
PubMed2003

[Meningioma: a model of cytogenetic evolution in tumoral initiation and progresion].

Meningiomas are tumors of the central nervous system with a great morphological heterogeneity. They are generally benign, and have the capacity to progress to a higher histological grade (atypical and anaplastic), which is associated with an increase in biological aggressivity and/or capacity to recur. Citogenetically this evolution is characterized by total or partial monosomy 22 in the early phase, continued by numerical and structural changes during tumor progression. In this study, we present a review of 85 cases of meningiomas: 43 benign, 28 atypical and 14 anaplastic. We study the clinical and histopathological features, and their correlation with cytogenetie abnormalities present in these tumors. Numerical aberrations such as monosomy of chromosome 10, 14 and 18, and structural abnormalities such as deletions on 1p are directly associated with a higher agressivity of tumors. An association of aberatons on 1p and chromosome 14 are more commonly found in atypical and anaplastic meningiomas. These facts imply that the presence of complex karyotypes progressively increases from grade I to grade III meningiomas. Furthermore, these karyotypes are common in recurrent tumors.

Adult↗
PubMed2003

[Oligoastrocytoma with signet-ring cell differentiation. A morphological, ultrastructural and immunohistochemical study].

We present a case of a mixed glial tumor (oligoastrocytoma) with signet-ring cells. This cellular feature is a rare differentiation in glial tumors of the central nervous system. Histological, immunohistochemical and ultrastructural findings have been analyzed. Signet-ring cells showed intense expression with GFAP, S-100 and vimentin. A differential diagnosis with other primary brain tumors and cerebral metástases with signet-ring cell differentiation was discussed.

Adult↗
PubMed2001

Lamellar organic thin films through self-assembly and molecular recognition.

Molecular clips possessing U-shaped cavities have been functionalized on their convex side with long aliphatic tails. These molecules form dimers which self-assemble into malleable lamellar thin films. Upon addition of a guest (methyl 3,5-dihydroxybenzoate), a 1:1 host-guest complex is formed, which prohibits clip dimerization. As a result, the lamellar structure of the material is lost. Complexation of 3,5-dihydroxybenzoic acid in the clip results in host-guest complexes which dimerize by hydrogen bonding interactions between the carboxylic acid functions of the bound guests. This dimerization restores the lamellar type architecture of the material.

Journal Article↗
PubMed2001

Biomechanical testing and clinical experience with the OMEGA-21 spinal fixation system.

The role of spinal instrumentation is to provide mechanical stability, obtain and maintain anatomic alignment, and promote fusion. The American Society for Testing and Materials (ASTM) introduced guidelines and procedures so that biomechanical properties of different implant designs could be compared in a consistent manner. Combined with biomechanical analyses, clinical evaluation allows the safety and efficacy of a spinal implant system to be determined before construction. The objective of our study was to determine the biomechanical properties and clinical performance of the OMEGA-21 Spinal Fixation System. Static and dynamic (fatigue) biomechanical testing was performed per ASTM guidelines and recommendations on individual components and on the system assembled in a corpectomy model. Clinical and radiographic evaluation of 57 consecutive patients with indications for instrumented spinal arthrodesis of the lower dorsal lumbar and sacral segments of the spine was performed at a mean follow-up of 31.9 months. Static and fatigue testing revealed superior biomechanical properties of the individual components and of the assembled system. The mechanical-strength values of the system were comparable with maximum reported values for existing implant designs. At final clinical follow-up, 86% of patients obtained relief of their symptoms; 84% considered their clinical results to be excellent or good. Ninety-one percent of patients satisfied radiographic criteria for bony fusion. There were 5 implant-related complications: 2 misplaced screws (2 patients), local pain above the implant (2 patients), and 2 broken expansive screws (1 patient). Biomechanical and clinical results indicate that the OMEGA-21 system is feasible and performs well as a spinal instrumentation system for the lower dorsal, lumbar, and sacral spine.

Adult↗
PubMed2000

Prophylactic percutaneous sealing of lumbar postdural puncture hole with fibrin glue to prevent cerebrospinal fluid leakage in swine.

UNLABELLED: We explored the effect of fibrin glue injection at the site of dural puncture on cerebrospinal fluid (CSF) leakage in a swine model. Pigs were subjected to a lumbar dural CSF puncture in the sitting position with a 17-gauge Tuohy needle. Fibrin glue 1.4 mL was injected through the same needle into the epidural space. Evans blue dye was infused through the cisterna magna 15 min later, and the appearance of dyed CSF through the skin puncture and along the needle trajectory to the dura was inspected and categorized. In seven of eight animals, the CSF leak was sealed with fibrin glue. Control animals were injected with 1.4 mL saline. A sham operation group of animals underwent cisternal dye infusion without a lumbar puncture. CSF pressure at the cisterna magna was recorded throughout the procedure. No significant differences in the leakage indicators were found between the fibrin glue-injected and sham-operated group, whereas both groups showed significant differences with respect to the control group. The fibrin glue seal was effective against CSF pressures of 24.5 [17-31] cm H(2)O. We conclude that percutaneously injected fibrin glue is effective in stopping CSF leaks after dural puncture in this animal model. IMPLICATIONS: In this swine study, we repaired a cerebrospinal fluid leak after a dural puncture by percutaneously injecting tissue adhesive. The technique of percutaneous injection of fibrin glue seems promising for the prophylaxis of headache associated with cerebrospinal fluid leakage, and may be an alternative to an epidural blood patch.

Animals↗
PubMed1996

[Cutaneous pigmentation, only manifestation of porphyria cutanea tarda in a HIV-1 positive patient].

INTRODUCTION: Porphyria cutanea tarda (PCT) is an unfrequent disorder in patients with acquired immunodeficiency syndrome (AIDS) due to deficiency in uroporphyrinogen decarboxilase. The more frequent cutaneous manifestations are skin fragility and hypertrichosis. CASE REPORT: A 44-years-old man with AIDS presented an intense cutaneous hyperpigmentation, preferently involving sun-exposed areas. Histopathologic studies showed perivascular PAS-positive deposits. Biochemical studies confirmed the diagnosis of PCT. DISCUSSION: PCT should be included in the differential diagnosis of cutaneous hyperpigmentation in patients infected by human immunodeficiency virus (HIV).

Adult↗
PubMed1993

Centrocentral anastomosis of the proximal nerve stump in the treatment of painful amputation neuromas of major nerves.

The term "centrocentral anastomosis" is used to describe the end-to-end connection across interposed nerve grafts between paired fascicular groups of the proximal stump of a severed nerve. In 22 patients harboring a painful terminal neuroma following amputation of a lower limb (20 neuromas on the sciatic nerve and two on the peroneal nerve), a centrocentral anastomosis was performed on the end of the sectioned nerve to treat pain that had not improved with conventional conservative treatment. Follow-up review at 1 year revealed that the typical neuroma pain had disappeared in all cases, although sporadic diffuse pain persisted in four. Where previous phantom sensation was present, no change was observed. The results presented here are consistent with laboratory findings demonstrating the absence of neuroma formation after centrocentral anastomosis. Therefore, this technique is recommended for the treatment of painful amputation neuroma.

Adult↗
PubMed1992

Use of genomic fingerprinting in the characterization of Neisseria gonorrhoeae isolated in Valencia, Spain.

Ninety-five Neisseria gonorrhoeae organisms isolated in Valencia, Spain, were characterized by antibiotic sensitivity testing, auxotyping, serotyping, plasmid analysis and restriction endonuclease fingerprinting (HindIII digestion). Cluster analysis of the restriction patterns revealed that 31 isolates (32.6%) formed 12 clearly defined clusters. Penicillinase-producing Neisseria gonorrhoeae strains formed four of these groups. Eight groups of gonococcal strains were identified by auxotyping, although 83% of isolates belonged to two auxotypes (Proto, Pro-). Twenty-three different serovars were identified by serotyping. The serovar pattern IB/rop was found in 38% of isolates. A 60% coincidence was found between gonococcal groupings obtained by combination of auxotyping, serotyping and plasmid analysis and those obtained with the restriction enzyme fingerprinting technique. The specificity of enzyme restriction patterns of Neisseria gonorrhoeae is confirmed to be of practical importance in the epidemiologic study of gonorrhoea.

Bacterial Typing Techniques↗
PubMed1992

Genomic fingerprinting of penicillinase-producing strains of Neisseria gonorrhoeae in Valencia, Spain.

OBJECTIVE: To compare the value of different markers and their combinations with the restriction enzyme technique in the differentiations of penicillinase-producing N. gonorrhoeae (PPNG) strains. MATERIALS AND METHODS: 17 PPNG strains isolated from symptomatic, untreated male patients with urethritis were characterised by antibiotic sensitivity testing, auxotyping, serotyping, plasmid profile, and restriction endonuclease fingerprinting (Hind III digestion). Cluster analysis with the method of unweighted pair-group average (UPGMA) linkage was used to calculate similarity or dissimilarity for PPNG strains. MAIN RESULTS: Either auxotyping or plasmid profile alone differentiated three groups of PPNG strains, whereas the combination auxotyping/serotyping identified 10. Although the combination auxotyping/serotyping/plasmid profile and the restriction enzyme technique showed a similar discrimination ability (differentiation of 11 PPNG strains), genomic fingerprinting gave highly specific restriction patterns on individual gonococcal isolates. CONCLUSIONS: The combination of different markers gave more epidemiological information than the use of only one. The sequence of discriminating ability for PPNG strains was: auxotyping/serotyping less than auxotyping/serotyping/plasmid profile less than restriction patterns of genomic DNA.

DNA Fingerprinting↗
PubMed1992

[Membrane proteins electrophoretic profiles study applied to Neisseria gonorrhoeae epidemiology].

The analysis of electrophoretic profiles of membrane proteins is one of the epidemiological methods of bacterial typing. The profiles of membrane proteins of 95 isolates were studied for valuing their usefulness in the epidemiology of N. gonorrhoeae. The results were compared with the obtained using other characterization methods (auxotyping, serotyping and antimicrobial sensibility). The proteins I and II (PI and PII) showed clear differences between isolates. Only protein-I (PI) with constant molecular weight for each isolate was valid to discriminate between strains. It was observed correlation between serovariety IA and molecular weight of PI 33.6-36 kD, and the serovariety IB with molecular weight 35.5-37 kD. Though it wasn't possible discriminated between the different serovarieties. It was proved a sensibility decrease to penicillin, tetracycline and cloramfenicol in those strains with molecular weight of PI greater than 35.5 kD (serogroup WII/WIII). In the 80% of the isolates considered multiple antibiotic-resistant it was observed a significant increase of the membrane protein dough of 52 kD. All the strains with this protein increased were multiple antibiotic-resistant.

Electrophoresis, Polyacrylamide Gel↗
PubMed1991

High grade atrioventricular heart block in 2 adults with systemic lupus erythematosus.

We describe 2 patients with systemic lupus erythematosus (SLE) and high grade atrioventricular (AV) block. In one patient anti-Ro antibodies were positive. This antibody has been associated with congenital complete heart block in children of mothers with SLE; however, its role in adult high grade AV block is not clear. We reviewed the 8 published cases of adults with SLE and high grade AV block. The possible mechanisms that could be implicated in the pathology of high grade AV block are discussed.

Adult↗
PubMed1989

Use of intrathecal baclofen administered by programmable infusion pumps in resistent spasticity.

On the basis of previous experimental and clinical studies patients with severe spasticity due to spinal cord damage from multiple sclerosis in 8 cases and postraumatic paraplegia in 6 and resistent to all conservative treatments were selected for a trial with morphine and baclofen administered intrathecally through a catheter placed in the spinal subarachnoid space rostral to the affected segments and attached to a subcutaneous reservoir. Whereas morphine single injection did not show any benefit, baclofen bolus injection 30 to 60 micrograms, revealed a marked decrease of spasticity and associated symptoms in 8 cases. After checking the clinical effect during 3 weeks and changes in electroneurophysiological studies and bladder manometry the catheter was attached to a subcutaneous programmable pump able to be refilled percutaneously and administered baclofen continuously or more often following a multistep complex programme in total doses of 90 to 150 micrograms per day. After a mean follow-up of 5 months all cases showed an absence of spasms and pain, a notable improvement for bettering of sphincter functions and a marked muscle relaxation that improves motor capacity, leading to increased ambulation or mobility. Neither complications nor side-effects were observed.

Adult↗
PubMed1988

Intraventricular transplantation of omentum for treatment of hydrocephalus. An experimental study in dogs.

In 17 mongrel dogs an experimental non-communicating hydrocephalus was developed by intracisternal injection of kaolin solution. In 10 of them a portion of omentum was isolated and after suturing end-to-end and the vascular pedicle to the temporal artery and vein the graft was introduced transcortically into the lateral ventricle. Metrizamide ventriculography, intraventricular basal and pulse pressure amplitude, compliance and resistance to CSF drainage were performed to evaluate related changes after surgery. Brain and omentum specimens were submitted for pathological studies. In summary, intraventricular omentum transplantation reduced intracranial pressure, compliance and resistance in experimental hydrocephalus whereas ventricular size remained unchanged. Pathological studies showed graft survival in most animals.

Animals↗
PubMed1988

The quality and extension of nerve fibre regeneration in the centrocentral anastomosis of the peripheral nerve.

Centro central anastomosis (CCA) is the connection created by means of a nerve autograft placed between the fascicles of the proximal stump of a sectioned nerve. We have used this technique in the laboratory and in the human to avoid the formation of a terminal neuroma after amputation of a limb. The aim of the present study is to know what is the quality and how long is the progression of the regenerating nerve fibers coming from a fascicle and growing inside the nerve graft and into the other central fascicle. 56 male, adult, Sprague-Dawley rats were operated on. The 4 rats of Group I were used for control: the right sciatic nerve was exposed and dissected in its four branches. One piece of 10 mm was taken of each of the sural and the peroneal branches for hystological and histomorphometric studies. In the 16 rats of Group II, after the section of the sural and peroneal branches a terminoterminal suture between their proximal stumps was made. In the 16 rats of Group III a CCA with an interposed nerve graft of 7 mm was achieved. 5.5 and 6 rats of Groups II and III were sacrificed at 10, 40 and 365 days after the operation and the entire graft was taken for histological analysis. In the 20 rats of Group IV, 60 days after CCA, the graft was sectioned at its center to produce wallerian degeneration of nerve fibers. 10 days after this second operation the animals were sacrificed and the nerve specimens were taken for histological study.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1987

High-frequency cervical spinal cord stimulation in spasticity and motor disorders.

High frequency stimulation of the cervical spinal cord was used in an attempt to moderate motor disorders in 10 patients, 5 spastics, 3 dystonics and 2 with spasmodic torticollis. Through a C4 flavectomy a quadripolar flat electrode was introduced into the epidural space, placing the first terminal at C2. Electrical parameters for stimulation were established at 0.05-0.10 msec pulse width, rate of 200-1,400 Hz and amplitude to paresthesia threshold. Stimulation was delivered 1 hour on and 1 hour off during daytime. Subjective, clinical and/or neurophysiological initial improvement were initially observed in 9 cases, in which the stimulation system was permanently implanted. After a mean follow-up of 41.4 months all patients but one had a clinical and neurophysiological condition almost similar to the prestimulation one. To investigate the effect of the so-called high-frequency stimulation on the nervous system, 9 dogs were implanted following the same surgical technique and stimulated with analogous electrical parameters than in human practice. After follow-up of 8 months the pathological studies of the animals did not show any local or suprasegmental alterations on nervous structures except a local huge dural scarring reaction.

Adult↗