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S C Carter

Publications and source records attributed to S C Carter.

6 recordsLinked to original sources
PubMed1992

Linkage of Tunisian autosomal recessive Duchenne-like muscular dystrophy to the pericentromeric region of chromosome 13q.

Autosomal recessive Duchenne-like muscular dystrophy (DLMD) is a severe dystrophic myopathy. The incidence is unknown because of its clinical similarity to Duchenne muscular dystrophy (DMD). Three highly inbred DLMD families from Tunisia were analysed for chromosomal linkage using 135 polymorphic microsatellite markers. A significant lod score of z = 9.15 at theta = 0.03 was found with the 13q12 locus D13S115. Two additional 13q12 markers, D13S143 and D13S120, also gave significant lod scores. Therefore, the primary DLMD defect gene lies in the pericentrometric region of chromosome 13q.

Centromere↗
PubMed1992

Evaluation of two infrared autorefractors in pseudophakia.

We investigated the viability of using an objective infrared autorefractor to identify high corneal astigmatism (> 3.00 D) in a pseudophakic population. The eyes of 91 patients, who had recently undergone cataract extraction and intraocular lens implanation, were refracted manually and using two infrared autorefractors, a Canon RK-1 and a Nikon NR-2000. Autorefractor measurements were repeated to provide estimates of reliability for each instrument. LogMAR visual acuities were also recorded with both the manual and autorefractor corrections. Approximately 75% of repeat autorefractor measurements were within 0.50 D of the initial readings, and about 75% of measurements were within 1.00 D of the manual refractions. Visual acuities with manual corrections were, on average, one line better than with autorefractor corrections. By validating the autorefractors against manual refraction, the efficiency of the autorefractors for detecting astigmatism > 3.00 D was calculated. Setting the cut-off criterion to ensure high sensitivity (95%), so that almost all patients with > 3.00 D were detected, resulted in both instruments having a poor specificity of about 40%.

Adult↗
PubMed1991

Sex reversing non-disjunction of the Y chromosome produces exceptionally low sex ratio (% males) and hermaphrodites in the progeny of male BALB/cBm mice: the roles of the maternal genotype and the Y chromosome.

When females of 21 strains and hybrids were mated to BALB/cBm males to determine the role of the maternal genome in the sex reversing non-disjunction of the Y chromosome, (1) BALB/cBm and BALB/cBy and SJL/J females produced 39.5-41.5% males and 2.4-2.8% hermaphrodites; (2) SWR/J, A/HeJ, DBA/2J and C3HeB/FeJ produced 44.8-49.1% males and 0.2-0.7% hermaphrodites; (3) C3H/HeJ and three strains of C57BL produced normal sex ratios and no hermaphrodites; (4) four F1 hybrids produced 44.5-49.2% males and 0.3-1.9% hermaphrodites; (5) the seven CXB RI strains produced perplexing sets of data: 26.5%-52.0% males and 0.2-3.2% hermaphrodites. These results indicate that a partly dominant gene favouring non-disjunction occurs in the female genomes of BALB/c and SJL/J strains, an enhancing gene occurs in C57BL/6By and there may be others. Heterosis appears to favour normal mitosis. CXBH females produced 26.5% males and 3.2% hermaphrodites, indicating that non-disjunction may have occurred in every male zygote, thus providing models for the generation of Turner's syndrome, hermaphroditism and a predictable non-disjunction. Reciprocal crosses were made between SJL/J and BALB/cBm, followed by 20 backcrosses to the maternal strains, to exchange the Ys and produce two new consomic strains. Males from SJL-BALB/cBm-Y strain, when mated to CXBH females, sired 34.3% males and 4.3% hermaphrodites, whereas BALB/cBm-SJL-Y sired no hermaphrodites and the sex ratio of the offspring was normal. This shows that the non-disjunction involves only the BALB/cBm Y chromosome and is completely independent of genes on the X or autosomal chromosomes. These results indicate that the BALB/cBm Y chromosome is unable to interact normally with the mitotic spindles of some genotypes, particularly CXBH, BALB/c and SJL. The simplest hypothesis is that a primary non-disjunction occurs at first cleavage. This can produce an array of mosaics determined by chance in the many sampling events that take place during development and by the relative vigour and stability of the two original clones.

Animals↗