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Biomedical subjects

W E Marshman

Publications and source records attributed to W E Marshman.

11 recordsLinked to original sources
PubMed2001

Increased binocular enhancement of contrast sensitivity and reduced stereoacuity in Duane syndrome.

PURPOSE: To compare the binocular enhancement of contrast sensitivity and stereoacuity in patients with Duane syndrome and normal subjects. METHODS: Monocular and binocular contrast sensitivity functions were determined using a two-alternative, forced-choice method in 14 patients with Duane syndrome and 14 normal subjects. Monocular and binocular log minimum angle of resolution (logMAR) acuities were measured, and stereoacuity was determined using the Titmus and TNO stereotests. RESULTS: In the patients with Duane syndrome, the binocular enhancement of contrast sensitivity was increased across all spatial frequencies, although stereoacuity was reduced compared to that of the normal subjects. The increased enhancement was caused by a reduction in monocular contrast sensitivity rather than an increase in binocular contrast sensitivity. The patients with Duane syndrome also showed a generalized reduction of contrast sensitivity at high spatial frequencies. CONCLUSIONS: It is suggested that the combination of reduced stereoacuity and increased binocular enhancement of contrast sensitivity seen in Duane syndrome can be explained by a partial loss of binocular cortical cells, caused by intermittent misalignment of the eyes during early visual development.

Adolescent↗
PubMed2000

Congenital anomalies in patients with Duane retraction syndrome and their relatives.

PURPOSE: Although the high incidence of skeletal, neural, and other ocular problems has been identified in previous reports of large cohorts of patients with Duane syndrome, there has not been any documentation of anomalies in close relatives. Patients with Duane syndrome have a greater than 50% incidence of associated abnormalities that include deafness, other ocular anomalies, cranial nerve palsies, and skeletal abnormalities. This study was undertaken to review the experience of our strabismus service with patients who have Duane retraction syndrome (DRS) and to delineate the associated anomalies in them and their first-degree relatives. METHODS: A prospective study of all patients with Duane syndrome who were seen at the strabismus service at Moorfields Eye Hospital has been ongoing for the last 4 years. All patients were assessed for the presence of ophthalmologic features of DRS and then referred to the pediatric service for a physical and neurologic examination. First-degree relatives were also examined, and a family pedigree was generated. RESULTS: We have evaluated 68 patients with DRS, of which 60.2% were female patients. The left eye was involved at a ratio of 4:1 in unilateral cases. The number of bilateral cases was 57.3%. Among the patients with DRS, 46% had first-degree relatives with associated abnormalities. CONCLUSIONS: The high incidence of associated anomalies in patients and first-degree relatives may suggest that a common genetic defect is responsible. This has to be confirmed with molecular genetic studies, which were not performed on these families because of a lack of available resources. However, our findings may indicate that the inheritance of Duane syndrome is much higher than the 10% previously reported, if any congenital abnormality is accepted as DRS associated. Children with Duane syndrome may benefit from a full medical assessment, in view of the frequency of other abnormalities, and so may their siblings.

Abnormalities, Multiple↗
PubMed1999

The role of botulinum toxin A in acute-onset esotropia.

OBJECTIVE: To establish the effectiveness of botulinum toxin A (BTXA) in the treatment of patients with acute acquired concomitant esotropia. DESIGN: Retrospective, interventional, noncomparative case series. PARTICIPANTS: Fourteen patients presenting to the Strabismus and Pediatric Service at Moorfields Eye Hospital with acute-onset esotropia over a 6-year period (1991-1997). INTERVENTION: 2.5 units of BTXA injected into the unilateral medial rectus muscle of the deviating eye under electromyographic control. MAIN OUTCOME MEASURES: Pre- and postinjection angle of deviation, pre- and postinjection stereopsis, final level of stereopsis achieved, and whether corrective squint surgery was later required. RESULTS: Fourteen patients were identified, of whom eight were male and six female. The mean age at presentation was 5.4 years, and the average time from onset to attending the clinic was 18 weeks. The mean time from onset of acute esotropia to injection was 32.5 weeks. All patients, except one, showed considerable improvement in their manifest deviation after one injection of BTXA. Eight patients (57%) maintained high-grade stereopsis of 120 seconds of arc or better and long-term ocular alignment with toxin treatment alone. In total, 11 patients (79%) gained improved stereopsis and maintained satisfactory ocular alignment with toxin therapy and did not require squint surgery. Two patients (14%) did not maintain a stable ocular position after toxin treatment and later required squint surgery, gaining good ocular alignment and high-grade stereopsis. The one patient who did not respond to the initial BTXA injection refused all further treatment. The mean follow-up time was 22 months. CONCLUSIONS: Botulinum toxin therapy has a definite role in the treatment of children with acute-onset esotropia. It may well obviate the need for squint surgery. The safety and ease of administration of this treatment add to its merits.

Acute Disease↗
PubMed1999

Bilateral vitreous hemorrhages in an infant with low fibrinogen levels.

The finding of retinal or vitreous hemorrhage in a child under age 3 years may cause significant controversy with regard to the etiology, because it raises the suspicion of nonaccidental injury. Blood dyscrasias have been documented to cause retinal and vitreous hemorrhages in adults and children, but they have rarely been reported to be the cause of retinal hemorrhages in neonates. We report on a patient with a low plasma fibrinogen level who had bilateral retinal hemorrhage that proceeded to vitreous hemorrhage. This subtle abnormality of the blood clotting cascade caused significant retinal and vitreous hemorrhage in a child without risk factors for abuse.

Afibrinogenemia↗
PubMed1999

Role of botulinum toxin A in surgically overcorrected exotropia.

PURPOSE: The purpose of this study was to define the role of botulinum toxin type A (BTXA) in surgically overcorrected exotropia. METHODS: A retrospective review was performed using the BTXA clinic database of more than 3500 patients to identify patients with a consecutive esotropia. RESULTS: Sixty patients met the inclusion criteria; the patients' ages ranged from 5 to 80 years. Before toxin treatment, an average of 1.8 operations had been performed per patient. The mean distance deviation was 17 PD base out and near deviation was 18 PD base out. The time from the last operation to an injection of BTXA averaged 28.3 months. We divided our patient population into 2 groups: those with fusion potential and those with no expected fusion potential. Of the 36 patients with fusion potential, 15 patients achieved and maintained good ocular alignment and resolution of their diplopia with an injection of BTXA. In the 24 patients with no expected fusion potential, 4 patients (17%) achieved and maintained good alignment with an injection of BTXA. Although they were not cured, 10 additional patients chose to have repeated BTXA injections to maintain their ocular alignment, whereas only 2 patients required occlusive methods to eradicate intractable diplopia. Five patients had additional surgery, of which 3 patients obtained a functional result. CONCLUSIONS: BTXA has a role in surgically overcorrected exotropia for patients in whom a functional result may be obtained. BTXA is of less value for patients with poor binocular function. It has proved especially useful as a treatment given only once for 42% of patients who could regain high-quality stereopsis. The safety and ease of administration of this treatment add to its merit.

Adolescent↗
PubMed1999

Neurologic abnormalities associated with persistent hyperplastic primary vitreous.

BACKGROUND: Persistent hyperplastic primary vitreous (PHPV) is usually a unilateral ocular abnormality not associated with other systemic findings. We describe 16 patients, 7 with unilateral and 9 with bilateral PHPV, in whom significant neurologic abnormalities were identified. METHODS: The clinical records of 16 children referred to the Visually Impaired Program at a university-affiliated children's hospital in Vancouver were studied from 1970 to 1996. Further investigations, including electroencephalography, computed tomography and pediatric neurologic evaluation, were performed to ascertain neurologic deficits. RESULTS: Neurologic abnormalities were identified in three of the children with unilateral PHPV (hemiparesis, impaired coordination and homonymous hemianopia) and seven of the children with bilateral PHPV (ataxia, impaired coordination, hypotonia, spastic quadriplegia, microcephaly and deafness). INTERPRETATION: The possibility of underlying neurologic abnormality should be considered in patients with PHPV, particularly those with bilateral disease. Referral to a pediatric neurologist may be appropriate.

Abnormalities, Multiple↗
PubMed1998

Duane's retraction syndrome and juvenile Batten's disease: a new association?

BACKGROUND: Although Duane's retraction syndrome (DRS) represents less than 5% of strabismus patients presenting to an ophthalmology department, it is a difficult management problem that is often poorly treated. The developmental defect has been isolated to early in the embryonic period, but to date a chromosomal location is still uncertain. Neuronal ceroid lipofuscinosis (NCL) or Batten's disease is a lysosomal storage disease with autosomal recessive inheritance, which has been categorized according to the age of onset of symptoms. METHODS/RESULTS: We report on a patient with DRS who developed juvenile Batten's disease. CONCLUSIONS: These two abnormalities can both be inherited, but their association has not been previously documented.

Child, Preschool↗
PubMed1998

Congenital endophthalmitis following maternal shellfish ingestion.

PURPOSE: To highlight an unusual organism causing a unilateral endophthalmitis by transplacental spread. METHOD: We report a case of Plesiomonas shigelloides endophthalmitis, presenting in a newborn, with co-existing septicaemia and meningitis. There was a significant maternal history of diarrhoea associated with the ingestion of oysters 2 weeks prior to delivery. RESULT: The endophthalmitis was treated with parenteral antibiotics and topical mydriatics with complete resolution, although subsequent assessment of the affected eye suggests a poor visual outcome. CONCLUSION: Endophthalmitis in the newborn is an unusual clinical finding and usually presents with other manifestations of bacteraemia. Plesiomonas shigelloides is fortunately an infrequent cause of neonatal infection, but is associated with a high degree of morbidity and mortality. We postulate that this neonate acquired P. shigelloides via the transplacental route, and suggest that this organism be included in the list of 'other' causes of transplacental infection that has been abbreviated to 'O' in the acronym 'TORCH'.

Animals↗
PubMed1997

Simple choristoma of the anterior segment containing brain tissue.

We report an unusual case of a simple choristoma of the anterior segment that contained only brain tissue. The clinical characteristics and findings of pathological examination of this unusual ocular malformation were reviewed. A newborn girl was seen with a fleshy, highly vascular cystic mass arising from the inferior limbus and extending across the cornea. On a computed tomographic scan, gross disruption of the anterior segment was present, with subluxation of the lens into the cyst. Excision of the abnormal tissue was followed by evisceration; polyglactin (Vicryl) ball implantation; patch graft of the globe; and, later, prosthetic fitting. Pathologic findings showed a choristomatous malformation, containing only mature brain tissue. To our knowledge, a choristoma in which the sole constituent is brain tissue has not previously been reported.

Anterior Eye Segment↗
PubMed1994

Insertional mutagenesis inducing hypomyelination in transgenic mice.

Investigations of myelin disorders, in particular multiple sclerosis (MS), have concentrated on immunemediated damage to formed myelin, while there has been less emphasis on the molecular genetics of myelin formation. We have generated a transgenic mouse mutant (designated 2-50) which carries an insertional mutation in a locus regulating myelination. These mice carry a transgene comprising 1.3 Kb of the mouse myelin basic protein (MBP) promoter conjugated to a fragment containing exons 2 and 3 of the human c-myc gene. Positive mice show a significant reduction in myelin compared to controls and a shivering phenotype. Unlike other myelin mutants, all 2-50 mice lose the shivering phenotype and breed normally. Expression of c-myc is detectable in only 65% of transgene-carrying mice, and when present occurs at extremely low levels. This shows that the phenotype is caused by insertional inactivation of a gene necessary for myelination rather than ectopic expression of the transgene. The transgene was found by in situ hybridization to be inserted into a single site which is very distally located on chromosome 9. The 2-50 mice represent a unique model which will be ideal for investigating the molecular basis of myelin assembly and for developing gene therapy to promote remyelination in conditions such as MS.

Animals↗