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Biomedical subjects

S E Feldon

Publications and source records attributed to S E Feldon.

At least 37 records · Page 2Linked to original sources
PubMed1994

Rabbit lacrimal acinar cells in primary culture: morphology and acute responses to cholinergic stimulation.

PURPOSE: The rabbit lacrimal gland yields large numbers of viable acinar cells that, when exposed to carbachol, respond with accelerated protein release, fluid phase endocytosis (Lucifer yellow uptake), and Na/H antiport activation. The current study was undertaken to determine whether such cells exhibit similar responses after having been maintained in primary culture. METHODS: Cells were isolated from 2-kg, juvenile male New Zealand White rabbits and maintained in a supplemented DMEM/Ham's F-12 medium for up to 72 hours. RESULTS: Electron microscopy showed the organization of freshly isolated cells to be highly polarized, with secretory vesicles at one pole and nucleus at the other; vesicles were heterogeneous in size and in the electron density of their contents. The cells remained polarized after overnight culture, but the secretory vesicle population was more homogeneous in size and content, and the cells tended to aggregate. After 72 hours, roughly half the cells retained good morphology and cytoplasmic polarization, but the vesicles were enlarged and their contents less electron dense. Cells that had been maintained overnight responded to the addition of 10 microM carbachol with a 32.2% +/- 15.5% (n = 12, P < 0.04) increase in the total amount protein released during a standard 20-minute incubation. This represented a mean 125% increase in the temperature-dependent component of protein release. The protein secretory response was decreased to 14.6% +/- 6.1% (n = 3, P < 0.07) for cells that had been maintained for 72 hours. In the same samples, carbachol increased fluid phase endocytosis by 38.3% +/- 8.1% (P < 0.01) and 70.9% +/- 13.4% (P < 0.025), respectively. The protein secretory response was partially, and the endocytic response fully blocked by 1 mM atropine. CONCLUSIONS: This model could be useful as a simplified system in which to study regulation of acinar cell function over days, rather than hours, as is required in fresh tissue models.

Alkalies↗
PubMed1993

Orbital malignant peripheral nerve sheath tumors. Treatment with surgical resection and radiation therapy.

A series of three patients with primary orbital malignant peripheral nerve sheath tumors (MPNST) is presented. Two of our patients who were treated with surgery and postoperative radiotherapy are free of tumor recurrence. The third patient showed a good response to radiation therapy. While surgical excision remains the mainstay of therapy, our patients demonstrate the usefulness of adjuvant radiation therapy in this condition.

Adult↗
PubMed1992

Late overcorrection of hypotropia in Graves ophthalmopathy. Predictive factors.

The authors have occasionally noted Graves ophthalmopathy patients with stable, restrictive hypotropia who demonstrate excellent initial postoperative realignment, only to develop marked overcorrection within weeks to months after surgery. The charts of 12 consecutive patients who underwent a first operation for single, uncomplicated vertical muscle imbalance were evaluated. Five patients were identified who developed an overcorrection 2 to 5 months after surgery (overcorrected group). A stable comparison group of seven patients retained stable orthotropia after surgery. In cases of patients with late overcorrection, proptosis and superior rectus muscle volume, as measured preoperatively, were significantly greater than in the stable comparison group. There also was postoperative limitation of infraduction in most instances.

Adult↗
PubMed1992

Orbital lymphoma in a patient with Felty's syndrome.

A 72-year-old woman presented with a diffuse infiltrating soft tissue mass involving the entire right orbit. She had a pre-existing phthisis of the right eye secondary to retinal detachment, and had developed painless proptosis on the same side. Her medical history included rheumatoid arthritis, leucopenia, and an enlarged spleen, characteristics consistent with the diagnosis of Felty's syndrome. Risk of lymphoma is thought to be higher in patients with established connective tissue disorders. The case described herein, to our knowledge, represents the first report of an association between Felty's syndrome and orbital lymphoma. The symptoms of Felty's syndrome in our patient were initially attributed to spread of a malignant process involving the orbit.

Aged↗
PubMed1992

Evidence for a metabolic trigger for Leber's hereditary optic neuropathy. A case report.

A 9-year-old girl with recently diagnosed juvenile onset diabetes mellitus presented with signs and symptoms of bilateral optic neuropathy. Leber's hereditary optic neuropathy was suspected on the basis of a strong family history. Subsequent mitochondrial DNA testing was positive. Visual recovery occurred once the diabetes was well controlled. This case suggests that such metabolic compromise that occurs in diabetes may precipitate the clinical expression of Leber's optic neuropathy.

Child↗
PubMed1991

Graves exophthalmos unrelated to extraocular muscle enlargement. Superior rectus muscle inflammation may induce venous obstruction.

Exophthalmos is the most commonly measured sign of Graves ophthalmopathy, whereas enlargement of the extraocular muscles is the principal pathologic abnormality. The purpose of this article is to explore possible etiologies of increased volume of orbital fat and of proptosis in patients with no substantially increased total extraocular muscle volume. Computed tomographic scans of the 13 orbits reviewed in this study had the following characteristics in common: a fine, reticular pattern within the orbital fat, a prominent superior ophthalmic vein, and an enlarged superior rectus muscle. Quantitative analysis revealed that superior rectus muscle volume showed a statistically significant correlation with proptosis, whereas medial, lateral, and inferior rectus muscle volumes did not correlate with proptosis. Based on anatomic considerations, the authors postulate that superior rectus muscle enlargement alone may produce reduced venous outflow from the orbit, thereby expanding the apparent orbital fat volume and producing proptosis.

Adolescent↗
PubMed1991

Pituitary tumor volume as a predictor of postoperative visual field recovery. Quantitative analysis using automated static perimetry and computed tomography morphometry.

We attempted to define the relationship between the volume of pituitary adenomas and postoperative visual field recovery. Fourteen consecutive patients (27 eyes) were studied who presented with visual complaints and who were confirmed to have pituitary macroadenomas at the time of resection. For each eye, preoperative visual field loss in each quadrant as well as whole field loss were analyzed. Tumor volume was determined from computed tomography scans by summing serial axial sections. Statistically significant correlations (p less than 0.05) of preoperative superonasal and whole visual field loss with tumor volume were found. Postoperative visual field recovery was determined for each patient by subtracting the postoperative visual field loss from the preoperative field loss. Postoperative inferonasal field recovery was significantly correlated (p less than 0.01) with whole tumor volume, with markedly greater recovery in patients with tumor volumes of 5 cc or less. In general, tumor volume proved to be a poor predictor of postoperative visual field recovery.

Adenoma↗
PubMed1990

Graves' ophthalmopathy. Correlation of saccadic eye movements with age, presence of optic neuropathy, and extraocular muscle volume.

Quantitative infrared oculography was used to record saccadic eye movements of 49 patients with Graves' ophthalmopathy. Peak saccadic velocities were decreased in those patients who developed or presented with optic neuropathy. This effect was more pronounced for larger eye movements. Peak saccadic velocity also decreased as total extraocular muscle volume and limitation of ocular motility increased. For any given extraocular muscle volume, peak saccadic velocity was 40 degrees/s slower in patients 40 years or older than in younger patients. The relationship between velocity and motility limitation was most pronounced for intermediate muscle volumes (8% to 15% of total orbital volume). Saccadic velocities in those patients with optic nerve compression often improved following treatment. This study demonstrated that eye movement recording was a useful adjunct in evaluation of patients with Graves' ophthalmopathy. Furthermore, age-related lowering of peak saccadic velocities implicated changes of extraocular muscle structure as a factor in the development of optic neuropathy.

Adolescent↗
PubMed1990

Visual loss caused by rapidly progressive intracranial meningiomas during pregnancy.

Three cases of intracranial meningiomas occurring in young pregnant women are presented. The typical growth pattern of these tumors is slow, producing insidious and chronic visual disturbances. In contrast, during pregnancy meningiomas may follow a rapidly progressive course, producing dramatic and relatively acute visual loss. This accelerated growth pattern is probably mediated by hormone receptors in these tumors. Nausea, vomiting, and other symptoms caused by the tumor may be attributed to pregnancy, delaying the diagnosis. Symptoms may abate spontaneously after delivery only to recur with greater rapidity and severity during subsequent pregnancies. Hormone-responsive intracranial meningiomas must be considered in the differential diagnosis of visual disturbances during pregnancy. Close cooperation between the ophthalmologist, neurosurgeon, obstetrician, and neonatologist is essential for an optimal outcome. Although surgical excision remains the treatment of choice, hormonal therapy may be valuable in treating unresectable or partially resectable meningiomas.

Adult↗
PubMed1990

Graves' ophthalmopathy: V. Aetiology of upper eyelid retraction in Graves' ophthalmopathy.

The volume of the levator superior rectus muscle complex was determined from computed tomography scans of 152 orbits from 76 patients with Graves' ophthalmopathy. Clinically observed lid retraction and lid lag did not correlate with the levator/superior rectus muscle volume and did not correlate with limitation of vertical eye movements or inferior rectus muscle volume. These results do not support previously published hypotheses that muscle hypertrophy or levator/superior rectus muscle overaction secondary to inferior rectus muscle restriction are major causes of lid retraction and lid lag. Local adhesion of the levator muscle to fixed orbital tissues is postulated to be the most likely basis for the characteristic lid retraction and lid lag of Graves' ophthalmopathy.

Adolescent↗
PubMed1988

Infrared oculography of Duane's retraction syndrome (type 1).

Eye movements of two patients with Duane's retraction syndrome (type 1) were recorded using high-resolution infrared oculography. Slowed hypometric abduction was found. The dynamics of adducting saccades in the affected hypometric eye were normal, suggesting an absence of functional cocontraction of the medial and lateral rectus muscles. Therefore, narrowing of the palpebral tissue on adduction most likely reflects a reorganization of the central ocular motor pathways.

Adult↗
PubMed1988

Anterior ischemic optic neuropathy: classification of field defects by Octopus automated static perimetry.

Visual fields of patients with anterior ischemic optic neuropathy (AION) were classified according to quantitative criteria, using the Octopus perimeter. Although a significant altitudinal pattern of field loss was found in 55% of perimetric examinations, the "spared" hemifields routinely showed some loss of sensitivity. This finding, along with the diffuse loss of sensitivity in a high percentage of visual fields, indicates more extensive involvement of the circulation of the anterior optic nerve head than has previously been suggested. Furthermore, patients with diabetes mellitus alone were found to have a statistically separable pattern of visual field loss. The pathophysiologic implications of the visual fields in AION and their relationship to the clinical findings were investigated.

Adult↗
PubMed1988

Graves' ophthalmopathy: I. Simple CT estimates of extraocular muscle volume.

Graves' ophthalmopathy is an autoimmune inflammatory process affecting primarily the extraocular muscles. The enlargement of these muscles is responsible for most of the important manifestations of the disease, including proptosis, lid retraction, diplopia, and optic neuropathy. Recently the optic neuropathy has been shown to correlate with extraocular muscle volume as determined by computed tomography (CT). In the present study simplified measures of the extraocular muscles imaged by CT are described, which also correlate highly with the development of optic neuropathy.

Adolescent↗