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Biomedical subjects

J Vorro

Publications and source records attributed to J Vorro.

12 recordsLinked to original sources
PubMed1998

Caprine mucopolysaccharidosis-IIID: clinical, biochemical, morphological and immunohistochemical characteristics.

Several animal models have been developed for the mucopolysaccharidoses (MPSs), a group of lysosomal storage disorders caused by lysosomal hydrolase deficiencies that disrupt the catabolism of glycosaminoglycans (GAG). Among the MPS, the MPS-III (Sanfilippo) syndromes lacked an animal counterpart until recently. In this investigation of caprine MPS-IIID, the clinical, biochemical, morphological, and immunohistochemical studies revealed severe and mild phenotypes like those observed in human MPS III syndromes. Both forms of caprine MPS IIID result from a nonsense mutation and consequent deficiency of lysosomal N-acetylglucosamine 6-sulfatase (G6S) activity and are associated with tissue storage and urinary excretion of heparan sulfate (HS). Using special stains, immunohistochemistry, and electron microscopy, secondary lysosomes filled with GAG were identified in most tissues from affected goats. Primary neuronal accumulation of HS and the secondary storage of gangliosides were observed in the central nervous system (CNS) of these animals. In addition, morphological changes in the CNS such as neuritic expansions and other neuronal alterations that may have functional significance were also seen. The spectrum of lesions was greater in the severe form of caprine MPS IIID and included mild cartilaginous, bony, and corneal lesions. The more pronounced neurological deficits in the severe form were partly related to a greater extent of CNS dysmyelination. These findings demonstrate that caprine MPS IIID is a suitable animal model for the investigation of therapeutic strategies for MPS III syndromes.

Animals↗
PubMed1998

Clinical biomechanic correlates of cervical dysfunction: Part 4. Altered regional motor behavior.

The present study examined organizational patterns of individual muscular contributions to head and neck motion. Previous studies of asymptomatic subjects with cervical motor asymmetry identified significant kinematic and myoelectric alterations. The current study evaluated 34 asymptomatic subjects categorized as to symmetry group based on initial palpatory test comparing regional motion responses of the head and neck to sidebending right and left. Electromyographic techniques were used to study muscular activity, indicating contraction frequency for each muscle monitored during active and passive test motions. Subjects with diagnosed regional motion asymmetry exhibited a significantly altered organization of electrically active and electrically silent muscles. Their pattern of muscle contraction was compromised just as frequently in the passive as in the active phases of motion. A positive sign of motion asymmetry on physical examination of the cervical region alerts the physician early to the presence of significant dysfunction in motor organization for efficient head/neck movement. The adaptive motor patterning in dysfunction can occur before the appearance of subjective pain.

Adult↗
PubMed1991

Clinical biomechanic correlates for cervical function: Part III. Intermittent secondary movements.

Parts I and II of this study compared kinematic and myoelectric data for two groups of asymptomatic subjects classified as having symmetric or asymmetric motor response to a palpatory test for cervical sidebending. Kinematic data revealed that asymmetric subjects had limited mobility for primary and secondary motions. Myoelectric activity was slow to be initiated in the asymmetric subjects, and reduced in time and strength of contraction. Part III addresses additional specific kinematic data concerning three-dimensional orientations of the head; however, these data were accumulated throughout the paths of movement, not just at their end points as in our previous work. Although asymmetric subjects had demonstrated significantly reduced range of motion, paths of the more minor secondary axes did not differ significantly between groups. As with previous data (Part I and II), active and passive movements were undifferentiated; this degree of likeness in even minor aspects of the motor performance continues to indicate the remarkable similarities that can exist between primary movements directed and guided by trained physicians and those actively controlled by patients themselves. Part III completes a study of cervical motor behavior in which a passive gross motion test distinguished an asymmetric group with subclinical motor behavior that has measurable kinematic and myoelectric correlates.

Biomechanical Phenomena↗
PubMed1989

Chronic cervical dysfunction: correlation of myoelectric findings with clinical progress.

In this pilot study, four patients with motion impairment and chronic cervical pain after cervical spine injury received osteopathic manipulative treatment for spinal dysfunction for periods in excess of 3 months. Records were compared for changes in the patient's subjective complaints, in the physician's findings, and in the standardized measurement of electrical activity of the cervical spine musculature. All three measures demonstrated parallel improvement in the health status of these patients. Attention to functional aspects of a neuromusculoskeletal problem appears to provide reliable indicators for directing treatment of somatic dysfunction and registering both subjective and objective change.

Adult↗
PubMed1981

Kinematic and myoelectric analysis of skill acquisition: I. 90cm subject group.

The purpose of this study is to define modifications in myoelectric activity and parameters of movement occurring during the acquisition of a novel motor skill. Twenty-three subjects practiced a shoulder flexion task, the goal of which was accuracy, for 103 trials at 1 sitting. The subject-to-target distance was 90cm. Synchronized cinematography and electromyography (EMG) were used to gather data intermittently throughout the learning sequence. The criterion measure, the performance score, was significantly altered during the learning sequence, with the majority of learning occurring very early in the practice period. To effect this alteration, results indicated that success required specific modifications in the kinematics of throwing behavior to include the following: 1) A 10% decrease in limb angle at ball release; 2) a decrease of 30% in the movement time for the limb excursion; and 3) a 60% increase in velocity of the limb at ball release. Alterations which occurred simultaneously in myoelectric variables included the following: 1) An early (within 3 trials) and sizable overall increase in total electrical activity for agonists and antagonists alike; 2) an increase in premovement activity for each of the muscles; 3) changes in coordination or the sequential firing of the various muscles; 4) alterations in the times needed to reach peak electrical activity; and 5) replacement of variables representing total electrical output by myotemporal variables, indicating that the subjects became dependent upon minor adjustments in temporal sequencing later in the practice session for any further performance refinements or improvements.

Adult↗
PubMed1981

Kinematic and myoelectric analysis of skill acquisition: II. 150cm subject group.

This experiment was conducted as a direct variation of a previous report. All electromyographic (EMG) and kinematic procedures were identical to those reported earlier; however, a new sample of 23 subjects practiced the shoulder flexion taken at a different subject-to-target distance (150cm) in an effort to establish whether similarities or differences existed between this and the previously developed model of skill acquisition. The criterion measure was again significantly altered during the learning sequence, and the majority of learning occurred within the first few trials. Kinematic and myoelectric measurements followed patterns similar to those reported in the previous model. To develop and maintain accuracy at the task, the subjects in the 150cm group found it necessary to decrease the projectile angle (19%), decrease the movement time (20%), an increase in the velocity of the limb at ball release (50%). Myoelectric activity commensurate with these kinematic changes included the following: 1) a considerable overall increase in total electrical activity for all muscles; 2) increases in premovement muscular activity for all muscles; 3) alterations in muscle firing order; and 4) replacement of variables representing total electric output by temporal variables later in the practice sessions. As indicated by the performance score, the added subject-to-target distance increased the difficulty of the task. Empirical observation concludes that the pattern of skill improvement was essentially similar for both groups.

Adult↗
PubMed1978

Kinematic and electromyographic differences between men and women during skill acquistion: a preliminary study.

The purpose of this preliminary study was to examine kinematic and muscular differences between male and female subjects during acquisition of a novel throwing skill. The task consisted of an underhand ball toss for accuracy and involved 10 male and 10 female subjects who each practiced the task for 104 trials during one sitting. A high speed 16 mm camera was used to gather the cinematographic data, and surface electrodes monitored the electrical output of the anterior and posterior portions of the deltoid muscle. Statistical analysis revealed significant differences between male and female subjects in 1) integrated electrical activity of the posterior portion of the deltoid muscle, 2) premovement activity of both the anterior and posterior portions of the deltoid muscle, 3) peak velocity of the movement, and 4) velocity of the limb at ball release. Differences may exist between men and women in kinematic and muscular modifications occurring during the acquisition of a novel throwing skill.

Adolescent↗