Search PubMed⌕ Search

Biomedical subjects

T A Cox

Publications and source records attributed to T A Cox.

At least 55 records · Page 3Linked to original sources
PubMed1989

Epiphyseal dysplasia, microcephaly, nystagmus, and retinitis pigmentosa.

In 1975, we reported two brothers with epiphyseal dysplasia, microcephaly, and nystagmus; one of them also had mild mental retardation. Here we present information on the natural history, particularly with respect to the development of a new visual problem, namely, retinitis pigmentosa.

Adolescent↗
PubMed1989

A retinopathy on Guam with high prevalence in Lytico-Bodig.

A pigmentary retinopathy resembling that sometimes seen in posterior ophthalmomyiasis interna was found in 26 (53.1%) of 49 Chamorro patients from Guam who have Lytico-Bodig (also known as amyotrophic lateral sclerosis-Parkinsonism-dementia complex of Guam). In nine cases, the retinopathy was bilateral. Similar changes were found in 6 (16.2%) of 37 clinically normal individuals from southern villages on Guam that have a high incidence of Lytico-Bodig, and in 1 (3.1%) of 32 individuals from Saipan, an island north of Guam that has a low incidence of the disease. These results indicate the possibility of an association-between Lytico-Bodig and a retinopathy on Guam that may be parasitic in origin. Occurrence of a similar association in other debilitating diseases on Guam and frequency of occurrence of retinopathy in Guamanians with Lytico-Bodig after leaving Guam have yet to be determined.

Adult↗
PubMed1989

Parasellar syndrome caused by plasma cell leukemia.

A 71-year-old man had incomplete third cranial nerve palsy caused by plasma cell leukemia and a parasellar plasmacytoma. This is the first reported case of plasma cell leukemia in which a central nervous system sign was the initial manifestation. Only one previous case of intracranial plasmacytoma associated with plasma cell leukemia has been reported. The characteristics of intracranial plasmacytomas and of plasma cell leukemia are discussed.

Aged↗
PubMed1989

Pupillographic characteristics of simulated relative afferent pupillary defects.

Relative afferent pupillary defects were simulated in normal individuals by performing the alternating light test while dimming the light in front of one eye with neutral density filters. Pupillary responses were elicited using a binocular photostimulator and recorded using a binocular television pupillometer. In five subjects, four spatial variables of the pupillary response--contraction amplitude, minimum size, final size, and redilatation amplitude--were measured and compared. Contraction amplitude was found to be the best indicator of small pupil defects. In eight other subjects, the contraction amplitude elicited by using filters from 0.3 to 3.0 log units in density was plotted. Amplitude of consensual responses increased as direct responses decreased, and initial constrictions were visible in many subjects at the 1.8 log unit level. The best method for detecting relative afferent pupillary defects using the alternating light test is to compare contraction amplitudes, looking for consensual responses that are greater than direct responses.

Adult↗
PubMed1989

Relative afferent pupillary defects in multiple sclerosis.

Relative afferent pupillary defects were found in 69 of 386 patients (18%) seen by the author at the University of British Columbia Multiple Sclerosis Clinic between Feb. 1, 1985, and Apr. 30, 1987. Pupil defects were more common in patients with clinically definite multiple sclerosis, those with recent or unilateral optic neuritis and those with unilateral or asymmetric optic atrophy. A relative afferent pupillary defect was found in 15 patients with no history of optic neuritis, 5 patients with no optic atrophy and 2 patients with normal visual evoked potentials. The frequency of relative afferent pupillary defects after optic neuritis in this group of patients was much lower than that found in a previous study of patients who presented with optic neuritis.

Adolescent↗
PubMed1988

Supranuclear disturbances of ocular motility in Lytico-Bodig.

We found abnormal supranuclear ocular or lid motility in all of 37 patients with Lytico-Bodig (amyotrophic lateral sclerosis/parkinsonism-dementia complex). Twenty-one patients had pursuit paresis, 18 abnormal vestibulo-ocular reflex (VOR) cancellation, 15 abnormal convergence, 13 abnormal optokinetic nystagmus (OKN), 12 conjugate gaze limitation, nine nystagmus, nine saccadic paresis, and six abnormal fixation. Lid abnormalities included glabellar hyperreflexia in 21, involuntary levator inhibition in three, and blepharospasm in two. Earlier reports have indicated infrequent ocular disturbances in Lytico-Bodig, but we now find supranuclear eye and lid deficits are universal and sometimes very prominent.

Aged↗
PubMed1987

Testosterone-related exacerbation of a prolactin-producing macroadenoma: possible role for estrogen.

Men with PRL-producing macroadenomas often present with hypogonadism and impotence. This report documents exacerbation of a PRL-secreting tumor after two separate 200-mg testosterone enanthate (T) injections despite continued bromocriptine (BRC) therapy. A 37-yr-old man with a 60-mm invasive tumor and a serum PRL level of 13,969 +/- 332 ng/ml (mean +/- SD) responded to BRC therapy with rapid disappearance of visual field defect, headache, and facial pain as well as decrease in serum PRL to 5,103 +/- 1,446 ng/ml. T injection was followed by severe headache, facial pain, and increase in PRL to 13,471 ng/ml. Visual field deterioration and increased tumor size (height, 40-43 mm) by computed tomography were documented. A relationship between T injection and exacerbation of the prolactinoma was not recognized until after a second T injection 3 months later. After that therapy, baseline PRL increased from 6,900 to 12,995 ng/ml. The hypothesis that T was aromatized to estradiol, directly stimulating lactotrophs, was supported by an increase in serum estradiol from 24 to 51 pg/ml after the second T injection. Although T treatment is accepted as appropriate therapy for hypogonadism in men with prolactinomas, it may not only interfere with the response of the tumor to BRC therapy, but even stimulate tumor growth and secretion.

Adenoma↗
PubMed1986

Pupillography of a relative afferent pupillary defect.

The pupillary reactions during the alternating light test of Levatin consist of bilateral pupillary constriction followed by redilatation each time the light moves from one eye to the other. The pupils constrict less and redilate more in an eye with an optic nerve lesion than in the unaffected fellow eye. The amplitude of pupillary responses and the average pupil size decrease when the light is alternated more rapidly. Placing neutral density filters over the better eye has the effect of decreasing the amplitude of pupillary responses when that eye is stimulated while increasing responses of the diseased eye. Because of contraction anisocoria and physiologic anisocoria, the most reliable pupillographic and clinical criterion for diagnosing a relative afferent pupillary defect using the alternating light test is an initial pupillary constriction in the suspected eye that is smaller with direct than with consensual stimulation.

Adult↗
PubMed1984

Contraction anisocoria resulting from half-field illumination.

We recorded pupillary responses to alternating half-field visual stimuli in 13 normal subjects (eight men and five women ranging in age from 23 to 28 years). We found that stimulation of the temporal visual field caused more pupillary constriction than did equivalent stimulation of the nasal field. Temporal stimuli also produced a direct pupillary response that was larger than the consensual response. Nasal stimulation, however, elicited a larger consensual pupillary response than a direct response. Our findings imply an asymmetric decussation of pupillomotor pathways in the midbrain in humans, as well as greater sensitivity of the nasal retina.

Adult↗
PubMed1983

Functional visual loss. Follow-up of 42 cases.

Forty-two patients with diagnosed functional visual loss were reexamined an average of four years after their initial visit. Twenty-three patients continued to have constricted or spiral visual fields at follow-up. Despite persistent evidence of functional visual defects, few patients were either socially or economically impaired by them. Patients who had other types of visual field loss or loss of visual acuity were more likely to have these signs resolve than were patients with constricted or spiral fields. Concurrent unrelated organic ocular disease was present in 11 patients. In 20 patients, it was not possible to identify psychiatric symptoms either related to the onset of functional eye signs or at follow-up. Treatment did not substantially alter the course.

Adolescent↗