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Biomedical subjects

H S Thompson

Publications and source records attributed to H S Thompson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of light on the prevalence of simple anisocoria.

PURPOSE: Because simple anisocoria is believed to decrease in bright light, the authors determined the prevalence of simple anisocoria under different lighting conditions. METHODS: The authors measured the pupil size of 104 healthy subjects with infrared videography at four clinically accessible light levels: darkness; darkness with a hand-held light shining from below; room light; and room light with the hand light shining from below. RESULTS: Of the 104 subjects, 40 (38%) were men and 64 (62%) were women. The ages ranged from 12 to 71 years (mean, 36.3 +/- 12.5 years). The mean decrease in pupillary diameter from darkness to the brightest condition was 1.89 mm. Based on the traditional definition of a pupillary diameter difference of 0.4 mm or greater, the prevalence of simple anisocoria decreased from 18% in darkness to 8% in room light with the hand-held light shining from below. The prevalence of anisocoria varied considerably when other definitions were used. Repeated measures analysis of variance showed that pupillary area difference decreased with brighter conditions (P = 0.026). However, the ratio of the pupillary areas did not change with brighter conditions (P = 0.666). CONCLUSIONS: The prevalence of simple anisocoria decreases with brighter conditions based on pupillary diameter difference. However, this decrease is not apparent when anisocoria is expressed as pupillary area ratio. Those clinicians who measure pupils will find that simple anisocoria decreases in bright light. However, with gross observation where perception of an anisocoria may be related more to the ratio of the pupillary areas, simple anisocoria may not seem to change much with brighter conditions.

Adolescent↗
PubMed1995

Hourglass-shaped visual fields as a sign of bilateral lateral geniculate myelinolysis.

PURPOSE/METHODS: Bilateral visual field defects resembling an hourglass could be produced by bilateral lateral geniculate lesions. We recently encountered such deficits in a 37-year-old woman after an episode of central pontine myelinolysis. RESULTS/CONCLUSIONS: Automated static perimetry demonstrated the congruous visual field defects to involve both halves of the visual field. They were confirmed with kinetic perimetry, and they remained stable for four years. Magnetic resonance imaging demonstrated enhancing lesions characteristic of myelinolysis in each lateral geniculate.

Adult↗
PubMed1995

Horner's syndrome in subadventitial carotid artery dissection and the role of magnetic resonance angiography.

PURPOSE/METHODS: A 47-year-old man with a postganglionic Horner's syndrome and severe right facial pain was found to have a normal carotid angiogram. We obtained a magnetic resonance angiogram of the neck because of our continued clinical suspicion of dissection. RESULT/CONCLUSION: An area of hyperintensity was identified along the lumen of the right internal carotid artery, suggesting a subadventitial dissection. Magnetic resonance angiography is a noninvasive, sensitive technique for identifying some carotid dissections.

Aortic Dissection↗
PubMed1995

Bilateral central ptosis in acquired immunodeficiency syndrome.

A man with acquired immune deficiency syndrome suddenly developed bilateral complete ptosis and minor vertical gaze limitation. Magnetic resonance imaging revealed a lesion in the midbrain surrounding the sylvian aqueduct in addition to bilateral masses in the caudate nuclei. Pathologic examination showed that the caudate lesions were central nervous system lymphoma of B cell origin, but the midbrain lesion contained only signs of AIDS encephalopathy. The periaqueductal lesion involved the caudal central subnucleus and probably also the subnuclei of the superior and inferior recti of the oculomotor nuclear complex bilaterally.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Optic nerve compression from a basal encephalocele.

A woman developed headaches, transient visual obscurations, anosmia, and decreased visual acuity. Ocular examination showed bilateral pulsatile proptosis and disc edema with choroidal folds. Standardized ophthalmic echography showed absence of bony orbital roofs, prominent dural pulsations, direct apposition of brain parenchyma and orbital tissues, and echographic signs suggesting bilateral optic nerve compression. CT and MRI showed a large defect in the floor of the anterior cranial fossa. The cribriform plate, both orbital roofs, and sphenoid bones were displaced by a large basal encephalocele. Clinical improvement followed reconstruction of the anterior cranial fossa and decompression of both optic nerves.

Adult↗
PubMed1994

Ubiquitin changes in human biceps muscle following exercise-induced damage.

Changes in ubiquitin levels were characterized in human biceps muscle following high-force eccentric exercise. Volunteers performed damaging eccentric-isokinetic actions of the biceps muscle with the non-dominant arm. Protein extracts of biopsy tissue samples taken two days post-exercise were run on SDS polyacrylamide gels, analyzed densitometrically and revealed a 64% higher level of a protein band at 12 kD. New monoclonal immunoblotting techniques identified the band as free ubiquitin. On these blots, free ubiquitin increased in the exercised sample by 55% over the control, and ubiquitin conjugates of varying molecular weights follow a similar pattern. The changes seen in both free and conjugated ubiquitin suggest that their increases are involved in the response to exercise-induced muscle damage.

Biopsy↗
PubMed1993

The relationship between static perimetry and the relative afferent pupillary defect.

This study was undertaken to understand better how damage to the anterior visual pathway may affect the relationship between the visual and pupillomotor systems. The relative afferent pupillary defect and the interocular difference in visual field mean deviation (determined by the Humphrey Field Analyzer Statpac program) were correlated in 137 patients. A moderate linear correlation (r = .66) was found. In 25 patients tested by both static and kinetic perimetry, the correlation could not be significantly improved by considering field loss outside of 30 degrees. The correlation was further studied in four subcategories of diagnosis: optic neuritis (n = 36), idiopathic intracranial hypertension (n = 26), compressive optic neuropathy (n = 14), and anterior ischemic optic neuropathy (n = 7). In compressive optic neuropathy and idiopathic intracranial hypertension, the difference in mean deviation between the two eyes was associated with a larger relative afferent pupillary defect than in optic neuritis and anterior ischemic optic neuropathy. In optic neuritis, the correlation was the poorest. These results indicate that diseases of the afferent visual system may not necessarily affect visual threshold (as tested by static perimetry) and the pupillary light reflex (a suprathreshold test) in the same way.

Adolescent↗
PubMed1993

Suppression of collagen induced arthritis by oral administration of type II collagen: changes in immune and arthritic responses mediated by active peripheral suppression.

The oral administration of CII by gavage to WA/KIR rats before a conventional arthritogenic challenge with bovine CII in FIA reduced the incidence (by 23%) and delayed the onset of collagen-induced arthritis in about 50% of the animals. Selective changes in B cell and T cell responses to CII in animals treated this way are interpreted to indicate a state of tolerance or hyporesponsiveness to CII. Tolerant animals made less serum antibody, to bovine and rat CII, of the IgG2b isotype and more of the IgG1 isotype. Phenotypic and functional analysis of peripheral lymph node cells showed that those from tolerized animals expressed less MHC Class II, proliferated less and secreted less IgG2b anti-CII antibody in response to stimulation in vitro with CII when compared with cells from non-tolerant animals. However, this depression of the immune responses to CII seen in vitro was overcome when the cells were incubated with increasing amounts of CII. Tolerance could be transferred to normal animals. Spleen cells, and nylon wool-filtered splenic T cells (but not mesenteric lymph node cells) adoptively transferred hyporesponsiveness to normal recipients which were then less susceptible to collagen-induced arthritis. Transfer of serum from gavaged animals did not modify the susceptibility of normal recipients to arthritis. Spleen cells from gavaged animals suppressed proliferative and antibody responses in co-cultures in vitro with lymph node cells from animals immunized with CII in FIA. The suppressive spleen cell population contained more cells expressing MHC Class II, in both the CD8+ and CD4+ populations. These studies show that the oral administration of CII alters the subsequent immune response to the arthritogenic challenge and indicate that this oral tolerance of CII is due, not to clonal deletion or anergy, but rather to an antigen-driven active suppression mechanism that affects both T cells and B cells, most likely through the action of regulatory cytokines IL-4, IL-10 and TGF beta.

Administration, Oral↗
PubMed1993

Prevention of pristane-induced arthritis by the oral administration of type II collagen.

This is the first demonstration of a role for type II collagen in pristane-induced arthritis. Pretreatment with soluble type II collagen either lowers or raises the subsequent incidence and severity of pristane-induced arthritis. These effects are dependent upon both the dose and route of administration of the soluble type II collagen. Increasing doses of orally administered type II collagen lowered both the incidence and severity of pristane-induced arthritis. Conversely, increasing doses of intraperitoneally administered type II collagen increased both the incidence and severity of arthritis. This exacerbation of pristane-induced arthritis was accompanied by elevated B- and T-cell responses to type II collagen. These findings highlight the importance of the site at which antigen is encountered in influencing subsequent immune responses and extend the observations of the use of orally administered antigens to ameliorate experimental autoimmunity.

Administration, Oral↗
PubMed1991

Automated pupil perimetry. Pupil field mapping in patients and normal subjects.

The authors developed an automated method of pupil perimetry by linking an infrared video pupillometer to a Humphrey Field Analyzer. Software was developed to automatically analyze the pupil responses to focal light stimuli and display the results graphically. All 76 locations of Humphrey program 30-2 could be tested twice within 5.5 minutes and the relative sensitivity of the field was determined by comparing the amplitude of pupil constriction or latency time at each stimulus location. The mean pupil responses within annular areas at 3 degrees, 9 degrees, 15 degrees, 21 degrees, and 27 degrees were shown to be linearly related to log stimulus intensity over a 15 dB range under low level mesopic conditions (3.15 asb bowl background). In normal subjects, the superior temporal quadrant usually had the greatest mean pupillomotor response and the inferior nasal quadrant had the least. Pupil responses in the temporal field were larger than corresponding locations in the nasal field. Patients with visual field defects who underwent testing by pupil perimetry showed pupillary deficits in the same location within the field, providing evidence that pupil perimetry may be a useful, objective means of assessing visual field function.

Adolescent↗
PubMed1991

Pupillary constriction to darkness in a patient with blue-cone monochromatism.

A 17 year old male patient presented with bilateral photophobia, poor color vision, visual acuity 20/80-20/200, nystagmus, and showed normal fundi. Electroretinography revealed evidence of blue-cone monochromatism. This patient showed constriction of the pupils to darkness or the paradoxic pupillary phenomenon.

Adolescent↗
PubMed1990

Hydroxyamphetamine mydriasis in normal subjects.

Hydroxyamphetamine eyedrops are used to help localize the lesion in Horner's syndrome. Because normal variability in the response to the eyedrops may influence the interpretation of test results in patients with Horner's syndrome, we studied both the interocular variability of the drug's mydriatic effect within each normal subject and the variation between individuals. We used photographs to document the variability among 26 normal subjects. Hydroxyamphetamine hydrobromide 1% eyedrops (Paredrine) were placed in both eyes of normal subjects in the same way that patients with Horner's syndrome are tested. The drug produced a mean increase in pupil size of 1.96 mm (+/- 0.61 S.D.) in the 52 eyes tested. In normal subjects, the mydriatic effect of hydroxyamphetamine was symmetric in each pair of eyes. The mean interocular asymmetry of mydriasis as measured by the difference in dilation (right eye dilation minus left eye dilation) was -0.087 mm (+/- 0.29 S.D.). Thus, the variability of hydroxyamphetamine mydriasis from one eye to the other in a single subject was much lower than the variability between subjects.

Adult↗
PubMed1990

Hydroxyamphetamine mydriasis in Horner's syndrome.

We studied hydroxyamphetamine hydrobromide 1% (Paredrine) mydriasis in 54 patients with Horner's syndrome to determine its effectiveness in distinguishing preganglionic lesions from postganglionic lesions. The difference in pupillary dilation between the unaffected and affected sides was used as a measure of the hydroxyamphetamine effect. We found that patients who had clinical evidence of damage to the postganglionic neuron of the oculosympathetic pathway had less pupillary dilation on the affected side. In contrast, almost all patients judged to have clinical evidence of preganglionic lesions dilated more on the affected side. We determined the probability that a given difference in pupillary dilation between the involved and uninvolved side is the result of a postganglionic lesion.

Amphetamines↗