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Biomedical subjects

James E Jan

Publications and source records attributed to James E Jan.

9 recordsLinked to original sources
PubMed2007

Evidence supporting the use of melatonin in short gestation infants.

Pineal melatonin regulates circadian rhythms and influences sleep. Melatonin also has protective actions against tissue damage from free-radicals and other toxins. Evidence is presented that this indoleamine is involved in pre- and postnatal brain (and ocular) development and intrauterine growth. In the absence of maternal melatonin, short gestation infants have a prolonged period of melatonin deficiency. Melatonin supplementation, which has a benign safety profile, may help reduce complications in the neonatal period that are associated with short gestation. We believe that this treatment might result in a wide range of health benefits, improved quality of life and reduced healthcare costs.

Dietary Supplements↗
PubMed2006

Long-term outcome of children with cortical visual impairment.

Cortical visual impairment (CVI) is now the most common cause of visual impairment in children. Little is known about the long-term visual outcome. This study evaluates the outcome of children with congenital CVI. Using medical records, 423 children (225 males, 198 females) were identified with congenital CVI. Of these children, 259 had follow-up visual acuity assessments. The children's gestational age varied with 32 weeks or less representing 15.9%; 33 to 36 weeks representing 10.7%; 37 to 42 weeks representing 61.2%; and 43 weeks or greater representing 0.9% (11.3% of patients' gestational age was unrecorded). Clinical data were extracted and information regarding outcome was gathered. The majority of children showed improvement in their visual acuity levels after 2 or more years of follow-up. For the 194 children initially assessed before 3 years of age, 97 had improved, 75 were unchanged, 18 had deteriorated, and 4 had sub-optimal assessments. For the 74 children initially assessed at 3 or more years of age, 23 had improved, 44 remained unchanged, 3 had deteriorated, and 4 had sub-optimal testing. Children with better visual acuity levels at follow-up were more likely to have favourable cognitive outcomes (non-mental retardation) in 12.2% versus 2.8% (p<0.01). Similarly, favourable motor outcomes (independent ambulation) were present in 20.1% for those with better visual acuities versus 7.9% for those with poorer visual acuities (p<0.01). Our study demonstrates that the majority of children with CVI underwent improvement in visual acuity. Additional disabilities were common, but those children with better visual acuity outcomes faired better. Given the frequency of comorbid conditions, appropriate diagnostic assessment services are needed.

Atrophy↗
PubMed2004

Optic nerve hypoplasia with intracranial arachnoid cyst.

BACKGROUND: The frequent association between optic nerve hypoplasia (ONH) and other central nervous system abnormalities has been widely reported in the literature. Occasional reference has been made to arachnoid cyst as one of the associated findings. METHOD: The charts and neuroradiologic findings of the 40 patients with ONH seen in our department as well as the Visually Impaired Program during the past 8 years were reviewed. RESULTS: An intracranial arachnoid cyst was present in 5 of the 40 patients (12.5%) with ONH and visual impairment. These patients' clinical and neuroradiologic findings are reported here. CONCLUSION: The presence of an intracranial arachnoid cyst in a patient with hypoplastic optic nerves could occur as a coincidental association between these lesions. Alternatively, a common mechanism could give rise to both abnormalities. Three such possibilities-including damage to the developing visual pathway by the arachnoid cyst, absence of an axonal guidance molecule similar to netrin-1 identified in the mouse, or a common genetic mutation involving the myocillin gene causing both abnormalities-are considered.

Arachnoid Cysts↗
PubMed2003

Conscious visual abilities in a patient with early bilateral occipital damage.

A 21-year-old male presented with occipital lobes that were extensively damaged by bilateral infarcts present at birth. The absence of the striate cortex was confirmed with anatomic and functional MRI and high-resolution EEG. His cortical visual impairment was severe, but he retained a remarkable ability to see fast-moving stimuli. Horizontal optokinetic nystagmus could be elicited from either eye. Resolution acuity was close to normal providing the patient was allowed to move his head and eyes. The direction of motion in random-dot patterns could be discriminated with perfect accuracy at speeds above 2 deg/s, and the patient reported that he could 'see' the motion at fast but not at slow speeds. This conscious residual vision for motion is known as Riddoch's phenomenon, but it has never been reported in the complete absence of the striate cortex. Functional neuroimaging revealed activation that was outside the motion-responsive regions of the extrastriate cortex. This case demonstrates remarkable plasticity in the human visual system and may have implications for understanding the functional organization of the motion pathways.

Adult↗