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Biomedical subjects

R L Rosales

Publications and source records attributed to R L Rosales.

12 recordsLinked to original sources
PubMed2006

Pharmacology of botulinum toxin: differences between type A preparations.

Different types of botulinum neurotoxin (BoNT) block different proteins of the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) protein complex within cholinergic nerve terminals, producing blockade of cholinergic neuromuscular and autonomic synapses. Animal studies indicate the longest duration of action for BoNT type A (BoNTA) followed by types B, F, and E. Diffusion to adjacent and remote muscles may be related to protein composition, dilutions, volume, target muscle selection, and injection technique. A review of head-to-head, randomized, controlled trials of BoNTA preparations (Botox and Dysport) suggests that Dysport tends to have higher efficacy, longer duration, and higher frequency of adverse effects. Conversion factors between the preparations varied, however, and remain controversial. In clinical settings, a Botox:Dysport conversion ratio of 1:3 may be appropriate. Animal studies suggest a conversion ratio of 1:2.5-3. When therapeutic effects between these preparations are attempting to be equalized, Dysport seems to produce more adverse effects. In mice, Botox appears to have a better safety margin than Dysport and BoNTB. In rats, diffusion margins are similar for Botox and Dysport. Jitter derived from stimulation single-fiber EMG of injected and remote muscles show no differences between Botox and Dysport. Atrophy of extrafusal muscle fibers of injected and remote muscles do not differ between the BoNTA preparations.

Animals↗
PubMed2004

PARK6-linked autosomal recessive early-onset parkinsonism in Asian populations.

The authors performed linkage analysis in 39 families with autosomal recessive early-onset PD (AR-EOPD) negative for parkin and DJ-1 mutations. Eight families including three Japanese, two Taiwanese, one Turkish, one Israeli, and one Philippine showed evidence of linkage with PARK6 with multipoint log of the odds (lod) score of 9.88 at D1S2732. The results indicate worldwide distribution of PARK6-linked parkinsonism.

Age of Onset↗
PubMed1996

Extrafusal and intrafusal muscle effects in experimental botulinum toxin-A injection.

The effects of botulinum toxin-A was compared on both extrafusal and intrafusal muscle fibers in the biceps femoris of Wistar rats. Four days after injection no action potentials were elicited with stimulation single-fiber electromyography on the injected side. Fourteen days after injection, jitter became measurable and these values were increased on the injected side. Extrafusal muscle fibers began to atrophy on the 4th day and this continued to the 14th day postinjection. Atrophy was also evident and progressive in intrafusal muscle fibers. Increased terminal innervation ratios, end-plate spread of cholinesterase, and increased density of very small myelinated fibers in large intramuscular nerves were observed 14 days postinjection. Both extrafusal and intrafusal fibers are cholinergically innervated, and both were progressively affected by botulinum toxin, perhaps varying in degree only. In addition to partial denervation, Botulinum toxin effects in dystonia may also be related to modified spindle afferent discharge.

Adenosine Triphosphatases↗
PubMed1991

Genetic mapping of "Lubag" (X-linked dystonia-parkinsonism) in a Filipino kindred to the pericentromeric region of the X chromosome.

"Lubag" is an X-linked disorder causing dystonia and parkinsonism that has only been described in families from the Philippines, principally from the island of Panay. We have established linkage between the disease phenotype "lubag" and DNA markers which span the Xp11.22-Xq21.3 region by using a large Filipino family with 8 affected men in three generations. These DNA markers define an interval of about 20 centimorgans in the pericentromeric region of the X chromosome as the most likely site of the disease locus XDPD (X-linked dystonia-parkinsonism). XDPD has a maximum multipoint log likelihood ratio score (Zmax) of about 4.6 over the interval from Xq12 to Xq21.31 (DXS159-DXYS1X). The co-occurrence of dystonia and parkinsonism in lubag and in other known disorders suggests there may be a common pathogenetic mechanism. Identification of the genetic defect in this family may provide an important clue toward understanding the pathogenesis and pathophysiology of both dystonia and parkinsonism.

Adult↗
PubMed1988

Morphometry of intramuscular nerves in amyotrophic lateral sclerosis.

Morphometric analysis of 90 intramuscular nerves from the biopsied biceps muscles of 16 cases of amyotrophic lateral sclerosis (ALS) were done and compared with controls. In all fascicles (large and small) of ALS, the total number and the numbers of large and small myelinated fibers were significantly reduced to 52, 16, and 64% of controls, respectively. A histogram of the largest fascicles revealed a unimodal distribution and a shift to the left, showing a single peak at 1 micron diameter. The results indicate proximal and distal involvement of the most remote portions of the nerves to the muscle in ALS and support previous suggestions of a neuronopathy.

Adult↗
PubMed1988

Spinal roots of rats poisoned with methylmercury: physiology and pathology.

The evoked potentials in the ventral and dorsal roots were recorded independently by stimulating the sciatic nerve of both control and methylmercury-poisoned rats. Poisoned rats showed markedly decreased amplitudes but normal latencies of the potentials evoked in the dorsal roots. Potentials evoked in the ventral roots had normal latencies and amplitudes. Pathological correlates indicated acute axonal degeneration of the dorsal roots, with a significant decrease of the large and small myelinated fiber densities. The ventral roots were histologically unremarkable. Our pathological confirmation of the electrophysiologic changes in the methylmercury-poisoned rats enables us to substantially assess the pathophysiological aspects of acute lesions in the spinal roots.

Animals↗
PubMed1988

Clinical and morphometric analysis of biopsied biceps brachii muscles in adult-onset chronic proximal spinal muscular atrophy. With special reference to intramuscular nerves.

In a group of 16 cases with adult-onset chronic proximal spinal muscular atrophy, we performed a morphometric analysis of 88 intramuscular nerves in biopsied biceps brachii muscles and correlated this analysis with clinical and histochemical parameters. The total number of large and small myelinated fibres in all fascicles was reduced to 71%, 23% and 83% of control values, respectively. The percentage reduction of large myelinated fibres for each case was significantly correlated with duration of illness, biceps muscle power and histochemical atrophy factors. Histograms of large intramuscular nerve fascicles showed unimodal distributions and shifts to the left with single peak increases at 1 micron. The densities of small myelinated fibres in large fascicles correlated with counts of 'enclosed' muscle fibres in ATPase preparations. Compared with amyotrophic lateral sclerosis, a lesser reduction of large myelinated fibres, but a greater increase in small myelinated fibres, was noted in adult-onset chronic proximal spinal muscular atrophy. These findings imply that there is a less marked loss of myelinated nerve fibres with more effective reinnervation in adult-onset chronic proximal spinal muscular atrophy than in amyotrophic lateral sclerosis.

Adult↗
PubMed1988

Sural nerve morphology in asymptomatic uremia.

This study evaluates morphologically the sural nerves of two patients with acute and another pair with chronic uremia, both of whom had neither clinical nor electrophysiologic evidence of neuropathy. Morphometric changes indicative of myelin repair were noted in the chronic uremic case who had a shorter duration of renal failure but required dialysis. Also, changes suggestive of axonal degeneration were found in the case who had chronic uremia of long duration. Both cases of acute uremia did not reveal significant abnormalities. Structural changes in the sural nerves may precede clinical and nerve conduction derangements in uremia, specifically in chronic cases.

Acute Disease↗