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Biomedical subjects

T McKay

Publications and source records attributed to T McKay.

14 recordsLinked to original sources
PubMed1993

Genetic heterogeneity in neuronal ceroid lipofuscinosis (NCL): evidence that the late-infantile subtype (Jansky-Bielschowsky disease; CLN2) is not an allelic form of the juvenile or infantile subtypes.

The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative disorders characterized by the accumulation of autofluorescent lipopigment in neurons and other cell types. Inheritance is autosomal recessive. Three main childhood subtypes are recognized: infantile (Haltia-Santavuori disease; MIM 256743), late infantile (Jansky-Bielschowsky disease; MIM 204500), and juvenile (Spielmeyer-Sjögren-Vogt, or Batten, disease; MIM 204200). The gene loci for the juvenile (CLN3) and infantile (CLN1) types have been mapped to human chromosomes 16p and 1p, respectively, by linkage analysis. Linkage analysis of 25 families segregating for late-infantile NCL has excluded these regions as the site of this disease locus (CLN2). The three childhood subtypes of NCL therefore arise from mutations at distinct loci.

Alleles↗
PubMed1989

Nicardipine after spinal cord compression in the lamb.

To study the effects of the calcium channel blocker nicardipine on spinal cord blood flow and spinal evoked potentials, the following study was undertaken. After cord compression, which was productive of paraparesis, nicardipine was administered intravenously in 10 anesthetized lambs. Ten control animals were subjected to compression but received saline instead. Nicardipine produced a significant decrease in mean arterial pressure when compared to the control group. Thirty minutes after compression, spinal cord blood flow also was lower in the nicardipine group compared with controls. Spinal evoked potentials did not recover after compression in either group.

Animals↗
PubMed1985

Semantic activation of noun concepts in context.

A modified Stoop procedure was used to examine the role that context plays in guiding semantic access of unambiguous nouns in sentence contexts. The sentences either emphasized a high- or a low-dominant property of a noun that was the last word in the sentence or were control sentences. Each sentence was followed by the relevant high- or low-dominant property either immediately or after a 300-or 600-ms delay. There was significant color-naming interference (relative to control) for high-dominant properties regardless of biasing context in the immediate and delayed conditions. There was also significant color-naming interference for low-dominant properties in the immediate condition regardless of context. However, in the delayed conditions, the low-dominant properties led to color-naming interference only when preceded by sentence contexts biasing interpretation toward the low-dominant property. It was concluded that high-dominant properties function as core, or invariant, aspects of meaning and that initial semantic access is context independent.

Attention↗
PubMed1982

7 alpha-Alkyltestosterone derivatives: synthesis and activity as androgens and as aromatase inhibitors.

The 7 alpha-ethyl,propyl,butyl,3'-t-butoxypropyl,allyl,3'-hydroxypropyl 17-acetate, and 3'-chloropropyl 17-acetate derivatives of testosterone and the 7 alpha-3'-t-butoxypropyl, 3'-hydroxypropyl,3'-acetoxypropyl,3'-bromoacetoxypropyl, 3'-chloropropyl, and 2'-oxo-3'-bromopropyl derivatives of 4-androstene-3,17-dione were synthesized. The testosterone derivatives were found to lose androgenic and anabolic activity rapidly as the size of the group at the 7 position increased. Many of the compounds were tested as inhibitors of aromatase. The 17-keto compounds were more active than the corresponding alcohols and the enzyme was found to tolerate at least the bulk of a hydroxypropyl group at the C-7 alpha position.

Androgens↗
PubMed1978

Relative rates of absorption of fluid and protein from the peritoneal cavity in cats.

The relative rates of fluid and protein absorption from the peritoneal cavity of anesthetized cats were measured over 6 hours at an intraperitoneal pressure of 15 mm Hg and with intraperitoneal protein concentrations from 1-8 g%. The fractional absorption rates of fluid and protein did not change significantly over the 6 hours and were not significantly different from each other within each one hour period. In addition both fractional absorption rates were unaffected by the protein concentration of the fluid within the peritoneal cavity. Although the absolute rate of absorption is greatly increased by elevation of the intraperitoneal pressure, these data indicate that the process remains iso-oncotic as would be expected for lymphatic rather than transcapillary absorption.

Absorption↗
PubMedDate not supplied

Selecting and using a videokeratoscope for mapping of corneal topography (continuing education credit).

1. Modern videokeratography (VK) projects circular Placido rings onto the specular cornea where they are captured by a single or dual camera. The computer within the system employs electronic edge detection to analyze the reflected image(s), and a reconstruction algorithm transforms the two-dimensional circular pattern into a representation of the three-dimensional shape of the cornea. 2. The most familiar product of a videokeratoscope is a color-coded contour map of corneal surface power, in which cool colors represent low corneal powers and warm colors suggest high corneal powers. These maps provide both an accurate and highly intuitive method of determining the shape of the cornea. 3. The primary applications of VK are in determination of corneal curvature and astigmatism prior to and following refractive surgery, both photorefractive keratectomy (PRK) and radial keratotomy (RK), and in the diagnosis of keratoconus. Corneal mapping also is useful in the determination of other disease states. It is likely that within 5 years corneal topographical mapping will be mandatory measurement for all pre- and post-refractive surgery. 4. Consequently, every hospital and surgeon's office will soon have access to one or more videokeratoscopes. As systems become less expensive and more application-specific, the instruments will most likely become standard equipment for clinicians in the fitting of contact lenses. At that point, interaction with these systems will fall into the job description of virtually every nurse/technician. Many technicians will be called on to give quick selection criteria and advice to surgeons and physicians regarding videokeratography.

Cornea↗