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Biomedical subjects

J W Simon

Publications and source records attributed to J W Simon.

At least 55 records · Page 3Linked to original sources
PubMed1990

Optic disk elevation in Down's syndrome.

Of five children who had Down's syndrome with optic nerve head elevation, without associated intracranial lesions, three underwent enhanced computed tomography for which no abnormalities were found. Partial, complete, or intermittent resolution of the optic disk elevation occurred in three children. In none of the children were retinal vessel dilation, splinter hemorrhages, optic nerve drusen, subsequent optic atrophy, or apparent visual loss noted. All of the children were hyperopic, but only one child had a hyperopia of greater than 3.50 diopters.

Child, Preschool↗
PubMed1990

When is it safe to stop patching?

Prior reports indicate that about half of amblyopia patients successfully treated with occlusion subsequently require maintenance patching. This retrospective study was designed to discover what clinical characteristics might be associated with a stable outcome following primary occlusion. Included were 188 patients who: (1) had amblyopia related to strabismus, anisometropia or media opacity; and (2) were followed up for at least one year after successful primary occlusion. Patients who did not comply with treatment or who did not achieve equal vision were excluded. Their ages ranged from 2 to 119 months (mean 29 months). Eighty-eight patients (47%) who required no further occlusion were designated the clinically stable group (CSG). The remaining 100 (53%), who subsequently needed patching because of unequal acuities, constituted the maintenance patching group (MPG). CSG patients were older at the beginning (mean 33 months) and at the end (mean 40 months) of primary occlusion than were MPG patients (means 26 and 31 months). Primary occlusion was more likely to have been discontinued because of equal recognition acuities in CSG patients, while equal fixation behaviour or preferential looking was more likely in MPG patients. Distribution of diagnoses, severity of amblyopia at presentation, and length of follow-up were similar in the two groups. Visual outcomes at last follow-up were slightly better in the CSG (p = 0.002). We conclude that, in general, patching can be safely discontinued after the third birthday. Although follow-up after primary occlusion is important to ensure stable results in all patients, preverbal children are more likely to require maintenance patching.

Age Factors↗
PubMed1990

Binocularity following surgery for secondary esotropia in childhood.

Binocularity was assessed in children who developed large, constant esotropia following bilateral lateral rectus recessions for intermittent exotropia. Nine such patients were identified who warranted medical rectus recession. Seven were finally aligned within 6 prism dioptres after secondary surgery. Stereopsis measured 50 seconds or better in six of these patients and 200 seconds of arc in the seventh. Two patients had residual deviations: one child with 30 prism dioptres of residual esotropia had 400 arc seconds and the remaining patient, with 12 prism dioptres of exotropia and marked anisometropia, did not show stereopsis. Children with constant acquired esotropia for as long as two years may still have normal stereopsis after surgical alignment. The risk of losing binocularity because of a large overcorrection following exotropia surgery may be smaller than previously assumed.

Child↗
PubMed1989

Nostoc commune UTEX 584 gene expressing indole phosphate hydrolase activity in Escherichia coli.

A gene encoding an enzyme capable of hydrolyzing indole phosphate was isolated from a recombinant gene library of Nostoc commune UTEX 584 DNA in lambda gt10. The gene (designated iph) is located on a 2.9-kilobase EcoRI restriction fragment and is present in a single copy in the genome of N. commune UTEX 584. The iph gene was expressed when the purified 2.9-kilobase DNA fragment, free of any vector sequences, was added to a cell-free coupled transcription-translation system. A polypeptide with an Mr of 74,000 was synthesized when the iph gene or different iph-vector DNA templates were expressed in vitro. When carried by different multicopy plasmids and phagemids (pMP005, pBH6, pB8) the cyanobacterial iph gene conferred an Iph+ phenotype upon various strains of Escherichia coli, including a phoA mutant. Hydrolysis of 5-bromo-4-chloro-3-indolyl phosphate was detected in recombinant E. coli strains grown in phosphate-rich medium, and the activity persisted in assay buffers that contained phosphate. In contrast, indole phosphate hydrolase activity only developed in cells of N. commune UTEX 584, when they were partially depleted of phosphorus, and the activity associated with these cells was suppressed partially by the addition of phosphate to assay buffers. Indole phosphate hydrolase activity was detected in periplasmic extracts from E. coli (Iph+) transformants.

Cyanobacteria↗
PubMed1989

Acute acquired comitant esotropia.

Acute acquired comitant esotropia has been used to describe a dramatic onset of a relatively large angle of esotropia with diplopia and minimal refractive error. We describe six children aged 5 to 11 years who developed an acute non-accommodative esotropia with diplopia. Neurological examination, including CT scan, in each of these children gave negative results. We suggest that this is an unusual presentation of esotropia of undetermined aetiology. The diagnosis, clinical characteristics, and management are discussed.

Acute Disease↗
PubMed1988

Infantile exotropia in healthy children.

Constant exotropia is uncommon during the first year of life. We retrospectively identified 13 patients with large, constant exotropia during the first year of life which required surgery. Bilateral lateral rectus muscle recessions were done in all 13 cases. Only two patients have required reoperation. The clinical characteristics and management of this unusual condition are similar to those of infantile esotropia.

Exotropia↗
PubMed1987

Astigmatism associated with adnexal masses in infancy.

High degrees of astigmatism are common in infants with hemangiomas but have not been well documented with other adnexal masses. We reviewed records of 65 patients (69 eyes) with chalazions, epibulbar or orbital dermoids, hemangiomas, and dacryoceles. Astigmatism greater than +1.25 diopters (as high as +5.50 diopters) was most commonly associated with dacryoceles (eight of 12 eyes) and with hemangiomas (14 of 17 eyes). Plus cylinder axes were consistently oriented toward the lesion, and astigmatism tended to resolve with resolution of the lesions. Only one of the 17 eyes with dermoids and two of the 23 eyes with chalazions had astigmatism. Anisometropic amblyopia has been a prominent concern in the treatment of infants with hemangiomas. Patients with dacryoceles may be at similar risk. Repeated cycloplegic refractions are important in determining appropriate treatment of adnexal masses.

Amblyopia↗
PubMed1987

Surgical management of large angle congenital esotropia.

Ninety-seven patients with congenital esotropia with deviations of 50 prism dioptres or greater underwent large (6 and 7 mm) bimedial rectus recessions. The overall success rate with one operation was 83.5%. Judgment of final alignment was made at the last follow-up examination, six to 61 months (average 23.4 months) postoperatively. Large bimedial rectus recessions for congenital esotropia are an effective surgical treatment which does not significantly alter adduction.

Child, Preschool↗
PubMed1986

Spontaneous resolution of herpes simplex blepharoconjunctivitis in children.

We observed three children, aged 1 year 8 months to 9 years 7 months, in whom herpes simplex blepharoconjunctivitis resolved promptly without treatment. A fourth child, 8 years old, developed probable toxic manifestations from topical vidarabine. These manifestations, as well as the blepharoconjunctivitis, resolved when the medication was discontinued. Herpes simplex ocular infection without corneal involvement in children is usually benign and self-limited.

Child↗
PubMed1986

Further observations on the first documented outbreak of trichinosis in Hong Kong.

The first documented report of human trichinosis in Hong Kong is described comprising an outbreak amongst 20 Gurkha soldiers following a barbecue. The cardinal clinical features were fever, myalgia and facial oedema and the most useful laboratory tests were eosinophilia and elevated levels of creatinine phosphokinase. Gastrointestinal symptoms were uncommon. Seven patients who developed electrocardiographic abnormalities are the subject of an ongoing study. Four patients had psychiatric manifestations. Splinter haemorrhages, hypocalcaemia and evidence of renal dysfunction were absent. The parasite was recovered from 13 of patients and the diagnosis confirmed serologically in all. The value of the enzyme-linked immunosorbent assay (ELISA) for IgM and IgE antibodies is emphasized in that it is 100% specific and sensitive. Thiabendazole alone was used in treatment and all patients recovered.

Adolescent↗
PubMed1986

Failure of malaria chemoprophylaxis with a proguanil-chloroquine combination in Papua New Guinea.

Proguanil 200 mg daily and chloroquine base 300 mg weekly were used as prophylaxis for 120 British Army soldiers from Hong Kong on a seven-week jungle exercise in the highly malarious Sepik district of Papua New Guinea. Compliance was rigidly enforced. Four men developed falciparum malaria whilst in Papua New Guinea and one within a few days of returning to Hong Kong. After stopping chloroquine four weeks after returning to Hong Kong 11 cases of mixed vivax and falciparum malaria and three cases of falciparum alone occurred within a 16-week period. This proguanil-chloroquine combination allows an unacceptably high level of breakthrough malaria and cannot be recommended for visitors to the highly malarious areas of Papua New Guinea.

Chloroquine↗
PubMed1986

Functional visual loss in children.

Twenty-three children (16 girls, 7 boys, aged 6-17 years) who presented with the specific complaint of blurred vision were diagnosed as having functional visual loss. Symptoms were intermittent in seven children. Associated signs and symptoms were common and included headaches, visual field loss, diplopia, micropsia, voluntary nystagmus, and spasm of the near reflex. Our treatment consisted of reassurance and follow-up. Resolution of symptoms occurred within 24 hours in one third and within two months in three-quarters of our patients. Parental support and encouragement were associated with more rapid resolution. Recurrence of symptoms and late onset of somatic complaints were rare. Conflicts related to family or school environment were common. Four children had been sexually or physically abused. Our experience suggests that, regardless of the duration or severity of symptoms, functional visual loss in children can usually be treated with reassurance. We believe that psychiatric referral is not necessary for most patients. Sexual or physical abuse should be considered as a possible predisposing factor.

Adolescent↗
PubMed1986

Athetosis in typhoid fever.

A case of typhoid fever with neuropsychiatric features is described. These comprised confusion and delirium, meningism, a single major convulsion and bilateral athetoic movements. Athetosis has not previously been described in typhoid fever and must now be added to the long list of neuropsychiatric manifestations of this disease.

Adult↗
PubMed1986

Heat illness. A report of 45 cases from Hong Kong.

During the summer of 1985, 45 soldiers with heat illness were admitted to the British Military Hospital, Hong Kong. Twelve had severe heat stroke, the remainder heat exhaustion. This paper discusses the management and prevention of heat illness in the military context.

Electrocardiography↗
PubMed1986

Posttraumatic convergence insufficiency.

Convergence insufficiency was encountered following closed head trauma in 23 patients. The most common complaints included difficulty reading and diplopia at near. The severity of the head trauma varied. There was no correlation between the severity of the head trauma and the severity of the convergence insufficiency. A normal near point of convergence was encountered in six of the 23 patients; all six patients had abnormal convergence reserves when measured with prisms. Treatment consisted primarily of convergence exercises and prisms. Bilateral medial rectus resections were required in two patients. Response to therapy was variable and often incomplete. The anatomic localization of convergence insufficiency secondary to head trauma remains unknown, although lesions in the occipital lobe and upper midbrain both seem capable of producing this syndrome.

Accidents, Traffic↗