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Biomedical subjects

P Fells

Publications and source records attributed to P Fells.

At least 19 recordsLinked to original sources
PubMed1998

An ultrastructural and systemic analysis of glycosaminoglycans in thyroid-associated ophthalmopathy.

PURPOSE: To determine the ultrastructural localisation of glycosaminoglycans (GAGs) in the extraocular muscles (EOMs) of patients with thyroid-associated ophthalmopathy (TAO) and to see whether the quantity and type of GAGs present in blood and urine are markers of the disease. METHODS: Biopsies of affected EOMs were taken and studied by transmission electron microscopy (TEM). These were either fixed conventional for TEM, or in 0.5% tannic acid and others for immunogold staining. Serum hyaluronan (HA) was measured using a radioimmunoassay in patients with TAO as well as control subjects, and urinary GAG levels assessed by photometric quantitation of hexuronic acid after reaction with carbazole. The excretion pattern of the urinary GAGs was determined by discontinuous electrophoresis. RESULTS: TEM showed that there is a marked expansion of the endomysial space in TAO EOM biopsies as compared with non-TAO strabismus specimens. This is caused by an increased number of collagen fibres, interspersed with a granular amorphous material surrounding striated collagen fibres shown to be hyaluronan by immunogold staining. In contrast, serum hyaluronan concentrations were similar in TAO and control patients, although there was a statistically significant difference in the urinary GAG excretion between the two groups of patients examined. By discontinuous electrophoresis, chondroitin sulphate and heparan sulphate were present in both patients and controls. CONCLUSION: GAGs and in particularly HA are present at the EOM level in patients with recently inactive TAO. However, serum levels of HA and urinary GAGs are not sensitive indicators for their presence within the EOMs.

Adult↗
PubMed1997

Orbital decompression for thyroid eye disease: a comparison of external and endoscopic techniques.

The results of orbital decompression for thyroid eye disease are presented in a cohort of 33 patients. It was performed by an external Patterson approach in 21 individuals and in 13 by an endonasal endoscopic approach. The endoscopic approach was entirely comparable in respect of improvement in axial proptosis, giving a mean improvement of 4.4 mm as compared with a mean of 3.8 mm for the external approach, and produced a demonstrable improvement in visual acuity and perception of colour in three individuals, where this was compromised, and was associated with fewer complications.

Adult↗
PubMed1997

Adhesion molecule expression in vivo on extraocular muscles (EOM) in thyroid-associated ophthalmopathy (TAO).

TAO is an autoimmune condition characterized by mononuclear cell infiltration of the extraocular muscles (EOM) and/or the orbital fat/connective tissue with associated deposition of glycosaminoglycans (GAG) in the interstitial spaces. In this study, the presence and distribution of the vascular adhesion molecules intercellular adhesion molecule-1 (ICAM-1), endothelial-leucocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1) and the leucocyte integrins CD11a/CD18, CD11b/CD18, CD11c/CD18 were investigated. Nineteen EOM biopsies were collected from 17 patients with early (n = 6) and late (n = 13) TAO as well as from 12 non-TAO control patients. Consecutive cryostat sections of these biopsies were immunostained with MoAbs to the above-mentioned molecules and haematoxylin and eosin. Primary antibody binding was visualized using an avidin-biotin system. In early untreated TAO specimens, the interstitial and perimysial connective tissue surrounding EOM fibres and numerous mononuclear cells stained strongly for ICAM-1. In contrast, the vascular endothelial cells (ulex lectin-positive) stained strongly for ELAM-1 (E-selectin), VCAM-1 as well as ICAM-1. In late disease, the same distribution of immunoreactivity for ICAM-1, ELAM-1 and VCAM-1 was observed, but with significantly lower staining. The leucocyte integrins (CD11a, CD11b, CD11c) were again expressed at significantly higher levels in early TAO specimens compared with late TAO specimens and were minimal or absent in the EOM biopsies harvested from control patients. In conclusion, increased expression of adhesion molecules studied correlated with early active disease and was reduced in later stages.

Adult↗
PubMed1997

Analysis of extraocular muscle-infiltrating T cells in thyroid-associated ophthalmopathy (TAO).

TAO is characterized by an autoimmune process affecting the orbital contents. T cells have been suggested to have a major role in pathogenesis, but so far only limited data are available to clarify the extraocular muscle (EOM)-infiltrating T cell phenotype, antigenic reactivity and cytokine profile in TAO patients. In the present study, biopsies of affected EOM were taken and the infiltrating T cells isolated and expanded in vitro with mitogen. Their phenotype was determined by flow cytometric (FACS) analysis and compared with peripheral blood-derived T cell lines, treated in the same way from the same patient. Cytokines present in the supernatant after mitogen stimulation of the T cell lines were assayed by ELISA. In addition, cytokine mRNA present at the time of biopsy was determined by rapid RNA extraction from EOM and reverse transcription-amplification with specific cytokine oligonucleotide probes (IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, IL- 15, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha)). In the T cell lines from two patients, proliferation assays were carried out with antigens derived from thyroid gland, EOM and a thyrotropin (TSH) receptor preparation. Most T cell lines were CD4+, CD45RO+, and TCR alpha/beta+, both from the EOM and the peripheral blood. A wide variety of cytokines was detected by analysis of supernatants or mRNA, but the profiles were not identical comparing the two approaches. However, IL-4 was detected by both. Dose-dependent proliferation was observed in response to thyroid extract in a biopsy-derived T cell line. In conclusion, EOM-infiltrating T cells from patients with TAO, expanded in vitro, were chiefly CD4+ and produced a mixture of cytokines, including IL-4. The proliferation data suggest that there are thyroid-reactive T cells in EOM.

Adult↗
PubMed1997

The role of plain radiography in the management of suspected orbital blow-out fractures.

We reviewed the indications for radiography and its impact on management in 100 consecutive patients referred to the Radiology Department from the Accident and Emergency Department of a large eye hospital in order to assess the utility of orbital plain radiographs in patients suspected of having blow-out fractures. We assessed whether administration of antibiotics or referral for surgical or orthoptic treatment was influenced by clinical features, radiographic findings or both. Ophthalmologists interpreting the radiographs appeared to be guided by the presence or absence of physical signs. No patient in whom they overlooked a fracture which was not evident clinically was subsequently referred for surgery. All patients who did have surgery for complications of a blow-out fracture underwent pre-operative computed tomography. Neither referral for orthoptic treatment nor administration of systemic antibiotics was consistently influenced by the presence or absence of a fracture. Given these findings, and the observation that the decision to operate was guided exclusively by clinical rather than radiological criteria, we recommend that only patients with well-defined indications for surgery (enophthalmos of more than 2 mm at any time within the first 6 weeks following the injury, and/or diplopia in the primary and/or downgaze reading positions not showing evidence of resolving within 2 weeks of the injury) should undergo radiography.

Adolescent↗
PubMed1997

Motion detection deficits in infantile esotropia without nystagmus.

PURPOSE: To investigate whether adults with infantile strabismus but without latent nystagmus have abnormalities of horizontal motion detection. METHODS: Eleven adult subjects with infantile esotropia but without latent nystagmus and 15 control subjects were required to detect the onset of motion and drift direction of a sinusoidal, spatial frequency grating that moved with linearly increasing velocity. The grating was presented monocularly in paracentral vision at an eccentricity of 16.5 degrees with a field size of 18 degrees. The contrast of the grating was just above contrast threshold for visibility. RESULTS: The mean velocity threshold for detection of motion was raised significantly in the patient group compared with the control group. Nine of the 11 subjects with infantile esotropia demonstrated directional asymmetry for the detection of motion. Thresholds were elevated more often when the grating was moving nasally in the squinting eye and temporally in the nonsquinting eye, and raised thresholds were more prevalent in the squinting eye. CONCLUSIONS: The findings indicate that in infantile esotropia, the presence of motion perception deficits are not always associated with the development of latent nystagmus. The predominance of nasally directed motion deficits in the squinting eye and temporally directed motion deficits in the nonsquinting eye was unexpected and may have been caused by abnormal development of cortical motion processing.

Adult↗
PubMed1995

'Henderson's' relief of eyelid retraction revisited.

The purpose of the study was to identify those patients with thyroid eye disease and upper eyelid retraction who would benefit from Henderson's procedure (myotomy of Muller's superior tarsal muscle with graded division of levator aponeurotic fibres on the anterior tarsal plate). The clinical records of patients attending the Thyroid Clinic of Moorfields Hospital who had undergone Henderson's procedures were reviewed. Twenty-two patients (19 women, 3 men) had Henderson's procedures at age 35-69 years (mean 49.9), with a mean follow-up of 4.55 years. Eleven patients had bilateral upper eyelid surgery, 11 unilateral (33 eyelids). The pre-operative vertical palpebral apertures ranged from 11 to 19 mm (mean 13.95); the post-operative vertical palpebral apertures ranged from 8 to 15 mm (mean 11.45), a mean reduction of 2.5 mm (p < 0.001). Eight of twenty-two patients (36%) had further eyelid surgery and 3 of 22 (14%) had further surgery recommended because of persistent upper eyelid retraction, abnormal eyelid contour (lateral flare) and asymmetry. It is concluded that Henderson's procedure should be reserved for those patients with minor degrees of almost symmetrical upper eyelid retraction who do not have abnormalities of their eyelid contour.

Adult↗
PubMed1994

Extraocular muscle problems in thyroid eye disease.

In this paper methods of visualisation of the extraocular muscle changes in thyroid eye disease are discussed. The histopathology of extraocular muscle biopsies has been studied by both light and electron microscopy to show the type of cellular infiltration and the amorphous material in the extracellular matrix. A series of questions to which answers have not yet been found concerning thyroid eye disease are posed which may help to direct new research projects. Finally, in the last part of the paper, the surgical results in a series of 41 patients having ocular muscle surgery for diplopia and/or compensatory head postures due to thyroid eye disease are described. The conclusions drawn from these results are that one should maintain the patient euthyroid, establish by orthoptic measurements that the ocular movements have been stable for at least 6 months, treat by recessing tight muscles using adjustable sutures, and aim to undercorrect the vertical deviation at the time of adjustment.

Diplopia↗
PubMed1994

Mathematical analysis and experiment on the corneal reflex test in spectacle wearers.

An experimental study and mathematical analysis of the corneal reflex test was undertaken in spectacle wearers. In the experimental study, photographs were taken of the corneal reflex through spectacles and the conversion ratios determined as measured in degrees/mm. In the mathematical analysis, the magnification effect of the lens was elucidated by three methods: geometrical analysis; real measurement of magnification factor; and ray tracing analysis. The real measurement of the conversion ratios was in good agreement with the conversion ratios determined by the three mathematical analyses. These results clearly showed that the corneal reflex test can be clinically useful even in wearers of spectacles.

Blinking↗
PubMed1993

Association of familial Duane anomaly and urogenital abnormalities with a bisatellited marker derived from chromosome 22.

We report a spectrum of defects that were found in an 18-year-old girl who presented for investigation of primary amenorrhea. The patient was found to have Duane anomaly, left renal agenesis, absent uterus, bilateral sensorineural deafness, and bilateral preauricular skin tags and sinuses. Investigation of her family showed that her brother also had Duane anomaly, right renal agenesis, sensorineural deafness, and preauricular skin tags and that their father had preauricular skin tags. Cytogenetic analysis, including in situ hybridisation of peripheral blood lymphocytes, demonstrated a supernumerary bisatellited marker chromosome derived from the region of chromosome 22pter-q11 in the affected individuals. Our findings indicate that a gene or genes located in the region of chromosome 22pter-q11 may be associated with the Duane anomaly and the development of the urogenital tract.

Adolescent↗
PubMed1992

A scoring method for Hess charts.

A new scoring system for Hess charts is described. Scores for both horizontal and vertical deviations are calculated from the displacement of individual points on the Hess chart, using weighting factors for the centre, inner and outer zones. The scoring system was validated in a group of 24 patients undergoing surgery for paralytic or restrictive strabismus. Subjective scores were obtained from patients both before and after corrective surgery, and corresponding Hess charts were scored using the new system. There was a good correlation between the changes in subjective and objective score. Our scoring system has applications in both research and clinical practice, allowing objective analysis of changes in muscle balance in a variety of motility disorders.

Diplopia↗
PubMed1992

Aetiology and management of the 'detached' rectus muscle.

The clinical features and management of 17 cases of detached extraocular muscles are described. They are classified into four groups: (1) the muscle which is cut and lost during squint surgery, (2) the muscle which breaks during squint surgery, (3) the muscle which slips following squint surgery, and (4) the muscle which is damaged during facial or orbital trauma. The prognosis for group 1 is poor whereas groups 2-4 have a good chance of successful muscle relocation.

Humans↗
PubMed1991

Extraocular muscle surgery in myasthenia gravis.

Myasthenia gravis is typically a disease of young people in active employment who need a field of binocular single vision. Although it is systemically controllable with a good chance of spontaneous remission, persistent loss of binocularity may cause chronic disability. We report our experience of extraocular muscle surgery in five patients with stable myasthenia gravis and persistent double vision. Extraocular muscle involvement was selective, giving rise to incomitant and concomitant squints, with individual muscle overactions as well as underactions. Treatment was by conventional recession and resection procedures with the additional use of Faden and adjustable sutures where appropriate. In all five cases a larger, stable field of binocular single vision was established. It is concluded that extraocular muscle surgery may be beneficial in selected cases of myasthenia gravis.

Adolescent↗
PubMed1990

Association between Graves' ophthalmopathy and smoking.

Patients with Graves' disease were questioned by postal survey about their smoking history. There were significantly more smokers in the group with ophthalmopathy than in the group with Graves' thyrotoxicosis or controls. Patients with severe eye signs smoked significantly more tobacco than did those with less serious signs.

Adult↗