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Biomedical subjects

A L Murphree

Publications and source records attributed to A L Murphree.

60 records · Page 4Linked to original sources
PubMed1975

Dominant cone-rod dystrophy.

Six generations of a family were studied extensively allowing the description of an autosomal dominant dystrophy of both rods and cones. The dystrophy is characterized by onset between ages 6 and 8 with gradual decrease in vision and progression to the point of no light perception. Abnormalities of color vision, visual field, refraction, fixation behavior, fundus appearance, fluorescein angiography, electroretinography, electrooculography and dark adaptation are presented. The importance of this family in the classification of inherited retinal dystrophies is stressed and the need for an expanded classification is discussed. The role of genetic counseling is stressed in such severe diseases.

Adult↗
PubMedDate not supplied

Expression of recessive alleles by chromosomal mechanisms in retinoblastoma.

Inheritance of a mutation at the Rb-1 locus, which has been mapped to band q14 of human chromosome 13, results in predisposition to retinoblastoma. Cloned DNA segments homologous to arbitrary loci of human chromosome 13 and which reveal polymorphic restriction endonuclease recognition sequences, have been used to look for somatic genetic events that might occur during tumorigenesis. A comparison of constitutional and tumour genotypes from several cases indicates that tumorigenesis may result from the development of homozygosity for the mutant allele at the Rb-1 locus. The homozygosity in these cases results from mitotic nondisjunction, resulting in loss of the homologous wild-type chromosome, or from a mitotic recombination event.

Alleles↗
PubMedDate not supplied

Expression and amplification of the N-myc gene in primary retinoblastoma.

Retinoblastoma, the most common intraocular tumour of childhood, probably arises from embryonal cells and occurs in hereditary and non-hereditary forms. Recent evidence suggests that this retinoblastoma (Rb) susceptibility gene located at chromosome 13q14 is actually recessive. Knudson has proposed that the tumour is caused by two mutational events. This idea was extended by Comings, who suggested that dominantly inherited tumours may result from loss or inactivation of both alleles of regulatory or suppressor genes that, when active, prevent the expression of a structural transforming gene(s) (possibly an oncogene) normally active only during embryogenesis. Despite circumstantial evidence for this hypothesis, no activated oncogene has been identified. We now report that (1) the N-myc gene is amplified 10-200-fold in two primary retinoblastomas and a retinoblastoma cell line Y79 and (2) expression of N-myc gene is highly elevated in most of the retinoblastomas examined. This finding suggests that N-myc gene may have a primary role in the tumorigenesis of retinoblastoma.

Base Sequence↗
PubMedDate not supplied

Use of high dose chloral hydrate for ophthalmic exams in children: a retrospective review of 302 cases.

Although chloral hydrate sedation has been proposed as an alternative to evaluation under anesthesia for pediatric patients who are unable to cooperate with routine test procedures, a careful study of the drug's safety and effectiveness is lacking. This study reports the effectiveness and safety of high-dose chloral hydrate for ophthalmic examination in 302 patients between the ages of 1 month and 5 years. The patients had nothing to eat or drink for 4 hours prior to drug administration. The patients were monitored during sedation and until fully awake. Eighty-eight percent of the patients (266/302) were successfully sedated without a supplemental dose. There were no reports of any complications including emesis, respiratory distress or depression, behavioral problems, changes in vital signs, patient injury, or hospital admission. The high-dose chloral hydrate protocol described, results in safe and generally successful sedation of pediatric patients for ophthalmic examination.

Child, Preschool↗