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Biomedical subjects

C W Roberts

Publications and source records attributed to C W Roberts.

At least 73 records · Page 4Linked to original sources
PubMed1990

The t(10;14)(q24;q11) of T-cell acute lymphoblastic leukemia juxtaposes the delta T-cell receptor with TCL3, a conserved and activated locus at 10q24.

We cloned the t(10;14) recurrent translocation from CD3-negative T-cell acute lymphoblastic leukemia cells. The breakpoint at 14q11 involved an intermediate rearrangement of the delta T-cell receptor locus, suggesting that the translocation arose at the time of antigen receptor assemblage. Translocation introduced chromosome segment 10q24 as proven by hybridization of a breakpoint-derived probe to flow-sorted chromosomes and metaphase chromosomes. Two t(10;14) breakpoints were clustered within a 600-base-pair region of 10q24 but no heptamer-spacer-nonamer motifs resembling T-cell receptor/immunoglobulin rearrangement signals were noted at the breakpoint. A locus distinct from terminal deoxynucleotidyltransferase was found at 10q24. Evolutionarily conserved regions surrounding the 10q24 breakpoint were examined for transcriptional activity. A region telomeric to the 10q24 breakpoint, expected to translocate to the der(14) chromosome, recognized an abundant 2.9-kilobase RNA in a t(10;14) T-cell leukemia. This locus was not active in a variety of other normal and neoplastic T cells, arguing that it was deregulated by the introduction of the T-cell receptor. This locus is a candidate for a putative protooncogene, TCL3, involved in T-cell neoplasia.

Alleles↗
PubMed1990

Production of corneal lesions using high-intensity focused ultrasound.

In order to study the potential use of ultrasound as a noninvasive system for altering corneal curvature, we used high-density focused ultrasound at a frequency of 4.8 MHz and 7.9 MHz to produce corneal lesions in the rabbit eye. Intensity and duration threshold exposure conditions were determined for the production of minimally visible lesions. Threshold lesions were initially apparent as discrete white opacities resulting from stromal edema and disruption. Light and scanning electron microscopy of higher-energy, suprathreshold lesions revealed more extensive disruption, including the formation of a superficial stromal depression and a larger zone of edema and disorganization surrounding each lesion. Posterior stromal lamellae, endothelium, and Descemet's membrane were intact. Healing and reepithelialization resulted in a smooth corneal surface with no residual opacification. Threshold determinations predict safe exposure levels to the cornea during insonification of other ocular structures. Selective heating of the peripheral cornea using focused ultrasound may be a useful technique for correcting astigmatism.

Animals↗
PubMed1988

Response of human immunodeficiency virus-associated uveitis to zidovudine.

A patient with human immunodeficiency virus (HIV) type 1 infection developed chronic iridocyclitis and anterior vitritis that were poorly responsive to topical and systemic corticosteroid therapy. Anterior chamber paracentesis was performed and HIV was isolated from culture of aqueous humor. Subsequent treatment with oral zidovudine resulted in resolution of the iridocyclitis and vitritis and full functional recovery of the eye. This case suggests that HIV may be a cause of uveitis responsive to systemic zidovudine therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Specific cross-gender behaviour in boyhood and later homosexual orientation.

Data from a group of males aged 13 to 23, who as children exhibited extensive cross-gender behaviour, was analysed. In boyhood they frequently played with dress-up dolls, role-played as females, dressed in girls' clothes, stated the wish to be girls, primarily had girls as friends, and avoided rough-and-tumble play. The majority of the group evolved a bisexual or homosexual orientation; two types of behaviour, boyhood doll play and female role-playing, were found to be associated with later homosexual orientation. The findings suggest developmental associations between specific types of boyhood cross-gender behaviour and the objects of later sexual arousal.

Child Behavior↗
PubMed1986

Ultrastructural correlation of specular microscopy in retinoblastoma.

A patient with monocular retinoblastoma was examined with the wide-field specular microscope before undergoing enucleation. An unusual image on the corneal endothelium consisted of irregular oval dark structures within which bright reflections formed a lacy network. Light and electron microscopy confirmed these structures to be clusters of retinoblastoma cells adherent to the endothelium. These findings suggest that the specular microscope may aid in the diagnosis of intraocular tumors.

Cornea↗
PubMed1984

Endothelial guttata and facility of aqueous outflow.

Thirty-eight eyes of 22 patients with corneal endothelial guttata were examined by slit lamp, tonometry, tonography, and wide-field specular microscopy. The mean value for facility of outflow (C55) was 0.23, and it was not statistically different from reported values for a normal population. Also, there was no correlation between extent of guttata as seen with wide-field specular microscopy and facility of outflow. Thus, contrary to a previous report, endothelial guttata does not seem to predispose to impaired facility of outflow.

Aqueous Humor↗
PubMed1984

Noninfected corneal ulceration.

The pathogenesis of noninfected corneal ulcers consistently relates to persistent or extensive epithelial defects, concomitant with stromal inflammatory cell infiltration and enzymatic degradation of collagen and ground substance. The therapeutic approaches to these disorders may be considered on three levels: (1) determination of etiology and institution of primary therapy; (2) promotion of epithelial healing; and (3) limitation of ulceration and support of repair. The latter two aspects feature pharmacological management and limited surgical modalities, particularly the use of tissue adhesive.

Adrenal Cortex Hormones↗
PubMed1982

"Porcupine": a feather structure mutation in Japanese quail.

A type of feather structure abnormality in Japanese quail resulting from the failure of barbs to uncoil was found to be controlled by a single autosomal recessive gene, pc (porcupine). The mutation was first identified in two birds from a population homozygous for white plumage color. Porcupine quail have poor egg production, lower fertility, and higher embryonic and chick mortality compared to wildtype or heterozygotes.

Animals↗
PubMed1982

Short barb: a feather structure mutation in Japanese quail.

A type of feather structure abnormality in Japanese quail resulting in shortened barbs on contour feathers was found to be controlled by a single autosomal recessive gene, sh (short barb). The mutation was first identified in a full-sib family from the University of British Columbia wild type line. Unlike other feather structure mutations in Japanese quail reported previously in literature, the short barb mutation is not associated with poor reproduction.

Animals↗