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Biomedical subjects

A Rubio

Publications and source records attributed to A Rubio.

At least 109 records · Page 6Linked to original sources
PubMed1996

Coexistence of Huntington's disease and familial amyotrophic lateral sclerosis: case presentation.

We present the clinical, molecular genetic and neuropathological findings of an 81-year-old man with concurrent Huntington's disease (HD) and familial amyotrophic lateral sclerosis (FALS). His mother had been diagnosed clinically as having ALS. There was no known family history of HD, but a maternal uncle had died in a chronic care psychiatric hospital. The diagnosis of HD in the patient was suspected at age 66, after 8 years of personality change, hallucinations, agitation, cognitive decline and choreoathetosis. No symptoms of motor neuron disease were noticed at that time, but progressive weakness developed later. Postmortem examination revealed cerebral atrophy, marked atrophy of basal ganglia (grade 3), and atrophy of brain stem and spinal cord. The neostriatum displayed massive neuronal loss and gliosis. The neocortex showed changes characteristic of Alzheimer's disease. Pathological lesions also included loss of neurons and gliosis in the anterior horns, Clarke's columns and the hypoglossal nuclei; degeneration of the lateral corticospinal tracts, dorsal spinocerebellar tracts and fasciculus gracilis; and rare Bunina bodies and ubiquitin-positive filamentous skeins in motor-neuron perikarya. Molecular analysis demonstrated chromosome 4p16.3 expansion of trinucleotide repeats characteristic of HD. Analysis of Cu,Zn superoxide dismutase gene and heavy neurofilament subunit gene failed to demonstrate mutations. The concurrence of HD and FALS in our patient and three previously reported cases did not appear to be associated with cosegregation in other family members.

Aged↗
PubMed1996

Experimental study on neurorrhaphy of the recurrent laryngeal nerve in dogs.

The effectiveness of anastomosis of a divided recurrent laryngeal nerve was evaluated in six adult mongrel dogs. Videolaryngoscopy and evoked compound muscle action potentials in the intrinsic laryngeal muscles were performed at six months and the posterior cricoarytenoid muscles and recurrent laryngeal nerves were processed for histomorphometric studies. Recovery of compound muscle action potentials in all re-innervated muscles and histomorphometric findings confirmed a good grade of axonal regeneration. The most significant histomorphometric changes observed were: a reactive hypertrophy of type I fibres in the posterior cricoarytenoid muscles of the re-innervated side, and a high nerve fibre density in the distal stump to the anastomosis. However, incomplete recovery of motion and fasciculated movements of the re-innervated vocal folds were observed. Reduction of effective motor units in the re-innervated muscles might be a factor that cause incomplete restoration of vocal fold movements.

Action Potentials↗
PubMed1996

Infarcted spinal schwannoma: an unusual MR finding.

We present a case of infarcted schwannoma of the thoracic spine in a patient with acute cord compression. MR images did not enhance after contrast administration, which is highly atypical for schwannoma, but was in keeping with the pathologic findings in this case.

Acute Disease↗
PubMed1995

Selected leukodystrophies.

The clinicopathologic profiles of the major leukodystrophies (adreno-leukodystrophy, metachromatic leukodystrophy, globoid cell leukodystrophy or Krabbe's disease, Pelizaeus-Merzbacher disease, and spongy degeneration of infancy or Canavan's disease) are reviewed. Particular attention is paid to distinctive imaging characteristics, molecular advances, pathogeneses, and potential therapies.

Adolescent↗
PubMed1995

Delineation of thyroid hormone-responsive sequences within a critical enhancer in the rat uncoupling protein gene.

Uncoupling protein (UCP) is essential to brown adipose tissue (BAT) thermogenesis and, hence, to cold adaptation and energy balance. The sympathetic nervous system, via norepinephrine and cAMP, and thyroid hormone seem to be the major regulators of UCP expression. T3 potentiates the effect of norepinephrine and is essential for the adaptive response of this protein to cold. The goal of the present studies was to investigate whether T3 directly stimulates the transcription of the rat UCP gene, as suggested by in vivo results, and if so, to identify and characterize the sequences involved. We examined the gene sequence between 114 and -3623 by transient transfection analysis in JEG-3 and HIB-1B cells, a BAT-derived cell line. This 3.7-kilobase UCP insert makes the reporter gene responsive to cAMP (4-fold), T3 (4-fold), or both combined (12-fold). We identified an 82-basepair (bp) restriction fragment between -2317 and -2399, which we called thyroid hormone response sequence (THRS), that conferred T3 responsiveness to the UCP minimal promoter (4- to 12-fold) as well as to the thymidine kinase promoter (3- to 6-fold). T3 receptor bound to THRS in vitro, retarding its migration in electrophoretic mobility shift assays. Footprinting of THRS revealed two potential thyroid hormone response elements (TRE) separated by 27 bp: upTRE, -2391/-2376, 5'ACCCCTACTGAGGCAA; and dnTRE, -2348/-2334, 5'AGGGCAGCAAGGTCA. The mutation of these putative TREs caused loss of both T3 receptor binding and transactivation by T3. The analysis of the mutants also demonstrated that both TREs contribute in similar proportion to the T3 responsiveness of the UCP gene and that dnTRE is necessary for the potentiation of the cAMP effect by T3. Both TREs are located within a previously identified 212-bp enhancer element, flanked by sequences considered essential for BAT expression and norepinephrine responsiveness. Although they do not mediate thyroid hormone responsiveness, the sequences flanking THRS increase basal reporter expression and enhance the responses to T3. In conclusion, our results indicate that T3 can stimulate the transcription of the UCP gene and amplify the effect of cAMP acting directly on the gene. The presence of two functional TREs in a location critical to the control of the gene supports the importance of thyroid hormone for its expression and suggests the potential for interactions at the gene level that may explain the complexity of UCP regulation in vivo.

Animals↗
PubMed1995

Effects of thyroid hormone on norepinephrine signaling in brown adipose tissue. I. Beta 1- and beta 2-adrenergic receptors and cyclic adenosine 3',5'-monophosphate generation.

Brown adipose tissue (BAT) thermogenesis is activated by the sympathetic nervous system. BAT responses to norepinephrine are blunted in hypothyroidism and are rapidly restored by thyroid hormone. We examined in rats the effects of thyroid hormone on BAT beta 1- and beta 2-adrenergic receptors (AR) expression and capacity to generate cAMP in response to adrenergic stimulation. Both are reduced in hypothyroidism. The reduction in cAMP generation is equal to or greater than that in beta 1,2-AR; it is the same whether cAMP production is stimulated with norepinephrine, selective beta 3-AR agonists, or forskolin; and it is not affected by the inhibition of phosphodiesterase. Both beta 1,2-AR and the capacity to generate cAMP were slowly corrected by thyroid hormone. T3 normalized beta 1,2-AR between 1 and 2 days, whereas the improvement in cAMP generation lagged 1 or 2 days behind. Within 2 days of acclimation of athyreotic rats at 30 C, the number of beta 1,2-AR reached the euthyroid level, whereas exposure to 4 C decreased these receptors. We reached the following conclusions: 1) BAT beta 1,2-AR and capacity to generate cAMP are reduced in hypothyroidism; 2) the latter, however, is not explained by the reduction in beta 1,2-AR, but, rather, reflects a fault at the postreceptor level; 3) the reduction in beta 1.2-AR number is largely caused by the cold stress derived from the low metabolic rate of the hypothyroid state; and 4) the slow restoration of both receptor number and capacity to generate cAMP after T3 are not consistent with these defects being a significant factor in the previously reported blunted uncoupling protein responses to adrenergic stimulation in hypothyroidism.

Adipose Tissue, Brown↗