Search PubMed⌕ Search

Biomedical subjects

L M Wilcox

Publications and source records attributed to L M Wilcox.

33 records · Page 2Linked to original sources
PubMed1981

Comparative extraocular muscle blood flow.

This study was designed to quantitatively determined blood flow to the extraocular muscles (EOM) of animals showing a wide range of ocular motility Blood-flow values (ml/minute/gm) for EOM in primates (0.25 +/- 0.03), dogs (0.33 +/- 0.06), sheep (0.12 +/- 0.01), and geese (0.12 +/- 0.04) were determined using the Reference Sample Method with 15 +/- 3 micrometer 103Ru microspheres and complete cardiovascular monitoring. Mammalian EOM blood flow was significantly higher than that determined for other skeletal muscle; however, EOM blood-flow values for sheep were significantly lower than those for primates and dogs. No significant blood-flow differences were found between avian EOM and other skeletal muscle, reflecting the unique avian ocular anatomy. These data indicate that high blood flow is not a general property of EOM and suggest a relationship between functional ocular motility and blood flow.

Animals↗
PubMed1981

Congenital adduction palsy and synergistic divergence.

Electromyography of the medial and lateral recti muscles in the right eye of a 7-year-old boy with congenital variable exotropia demonstrated cocontraction. This explained the observed simultaneous abduction on attempted levoversion. Abduction of the right eye increased intraocular pressure to 25 mm Hg from 15 mm Hg. This synergistic divergence should be considered a variant of Duane's syndrome, and, like Duane's syndrome, may occur as the result of anomalies of the peripheral oculomotor nerves or of central synaptic alterations, or of a combined central and peripheral mechanism.

Adolescent↗
PubMed1980

Fluorescein angiography of the optic disc. A longitudinal follow-up study.

A comparison of two or more disc fluorescein angiograms performed on separate occasions was done on 60 eyes of normal subjects and patients with ocular hypertension, primary open-angle glaucoma, and low-tension glaucoma. Clinically stable patients did not show any change in their disc angiographic filling patterns. Eyes that developed new visual-field defects with increased disc cupping and pallor correspondingly showed new absolute filling defects or areas of hypofluorescence. In those with established field defects, however, further changes in the visual field occurred without obvious changes in the disc fluorescein filling defect. Surgical lowering of intraocular pressure with or without decrease in disc cupping and pallor did not result in visible improvement of the disc angiographic pattern. Thus, the development of new visual-field defects is associated with changes of the circulation of the optic disc.

Adult↗
PubMed1980

Autoshaping of abnormal children.

Three experimentally naive abnormal children were exposed to a terminal operant contingency, i.e., reinforcement was delivered only if the children pressed a panel during intervals when it was lighted. Despite the absence of both successive approximation and manual shaping, it was found that each child began to respond discriminatively within a small number of trials. These data replicated previous animal studies concerned with the phenomena of autoshaping and signal-controlled responding. It was also found, however, that one type of autoshaping, the classical conditioning procedure, had a powerful suppressive effect on the discriminative responding. An experimental analysis that consisted procedure, had a powerful suppressive effect on discriminative responding. An experimental analysis that consisted of intrasubject reversal an multiple baseline designs established the internal validity of the findings. The finding of rapid acquisition of signal-controlled responding obtained with the initial procedure is suggessted to have practical significance. The disruptive effects of the classical form of autoshaping are discussed in terms of negative behavioral contrast.

Adolescent↗
PubMed1980

Changes in the binocular fixation patterns and the visually evoked potential in the treatment of esotropia with amblyopia.

Using the binocular fixation pattern (BFP) and the visually evoked potential (VEP), thirteen amblyopic patients with comitant, non-accommodative esotropia with an angle range up to 30 delta were studied before and during occlusion therapy. A graded BFP with a stronger preferred fixation could be used to diagnose amblyopia. The BFP, however, showed no significant change with therapy despite improvement in acuity. In contrast, the VEP amplitudes, initially reduced in amblyopia, increased significantly as the vision responded to patching. The VEP was useful in diagnosing strabismic amblyopia and giving a predictive range of acuities.

Amblyopia↗
PubMed1980

The effect of complete tenotomy on blood flow to the anterior segment of the canine eye.

The relative importance of the anterior ciliary arteries to blood flow to the anterior segment and the quadrant distribution of blood to the iris, ciliary body, and ciliary processes were determined in canines with the use of 15 +/- 3 mum 103Ru microspheres with the reference blood flow method. Recti muscles were isolated in both eyes. Then with one eye serving as a sham-operated control, anterior ciliary artery blood flow was disrupted by recti tenotomy immediately prior to microsphere injection. Tenotomy resulted in a significant decrease in blood flow to the anterior segment (0.14 +/- 0.03 ml/min/gm vs. 0.26 +/- 0.05 in the untenotomized control) and to the unit iris, ciliary body and ciliary processes (I, CB, CP) (0.92 +/- 0.16 ml/min/gm vs. 1.44 +/- 0.22 in the untenotomized control). Blood flow values for the anterior segment and the unit I, CB, CP in the tenotomized eye were 50% to 60% of those of the control eyes, indicating that the majority of blood flow to the canine anterior segment is not disrupted by complete tenotomy. In the control eye, blood flow values for the medial quadrant of the unit I, CB, CP were significantly higher (p < 0.05) than those of the inferior or superior quadrants. Blood flow values for all quadrants in tenotomized eyes were 55% to 70% of those for control eyes. Therefore the anterior ciliary arteries do not contribute the majority of blood flow to the canine anterior segment.

Animals↗
PubMed1978

Ophthalmic features of chromosome deletion 4p- (Wolf-Hirschhorn syndrome).

By using the Giemsa banding technique we identified three patients with chromosome deletion 4p-. All had anterior segment anomalies, exotropia, blepharoptosis, antimongoloid palpebral fissures, hypertelorism, and disk abnormalities. One patient (Case 1) had Rieger's anomaly. Some clinical features in patients with 4p- are similar to those in patients with chromosome deletion 5p-, cri-du-chat syndrome, although 4p- individuals do not have the distinctive cry. The ocular features which distinguish 4p- from other deletions include normal tearing, some degree of blepharoptosis, and the preponderance of anterior segment signs.

Abnormalities, Multiple↗
PubMedDate not supplied

Hypoplasia of the optic nerve in association with porencephaly.

Two cases of hypoplasia of the optic nerve associated with porencephaly are described. The clinicopathological correlation of the double ring sign is presented and the possible mechanism of optic nerve hypoplasia being a secondary degeneration is discussed.

Adult↗
PubMedDate not supplied

Arachnoiditis and VECP change.

A five-year-old boy presented with tuberculous meningitis and subsequently developed amaurosis with optochiasmatic arachnoiditis (OCA) late in the convalescent stage of the illness. The visual evoked cortical potentials were correlated with the decreased and improved postoperative acuity. The diagnosis and classification of OCA have been discussed with emphasis given to prompt neurosurgical treatment.

Arachnoiditis↗