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Biomedical subjects

R S Sparkes

Publications and source records attributed to R S Sparkes.

At least 19 recordsLinked to original sources
PubMed1992

Assignment of the beta-subunit of rod photoreceptor cGMP phosphodiesterase gene PDEB (homolog of the mouse rd gene) to human chromosome 4p16.

The gene encoding the beta-subunit of rod photoreceptor cGMP phosphodiesterase (gene symbol PDEB, homolog of the mouse rd gene) is mapped to human chromosome 4 using somatic cell hybrids and further localized to the chromosome band 4p16 using in situ hybridization. A mutation in the mouse gene underlies the recessive trait of retinal degeneration in the rd mouse. Thus, the human homolog is a candidate for lesions causing retinal degeneration.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1979

Marked hypodiploidy in a case of acute undifferentiated leukemia.

A-29-year-old white man with acute undifferentiated leukemia had bone marrow cells with predominantly 42 chromosomes including several rearrangements. Following a brief induced "complete" remission, during which normal chromosomes were observed, bone marrow cells with 42 chromosomes but a different karyotype than before remission were found. Evaluation of that karyotype indicates not only a reduced chromosome count but also a reduced quantity of chromosome material.

Acute Disease↗
PubMed1979

Expression of esterase D and other gene markers in trisomy 13.

A gene dosage effect was observed for esterase D in a patient with trisomy 13. Isoelectric focusing of hemoglobin from the same patient showed three unidentified bands. A gene dosage effect for several other enzymes was not observed in two other patients with trisomy 13.

Chromosomes, Human, 13-15↗
PubMed1979

Prominent acrocentric chromosome satellites in child patients with mental retardation or psychiatric disorders; no IQ-satellite size correlation.

Child patients with mental retardation or psychiatric disorders were selected for the presence of prominent acrocentric chromosome satellites and highest or lowest IQ scores. No correlation was found between IQ scores, of which eleven were below IQ 54 and 16 above IQ 68, and the length of acrocentric short arm, satellite, stalk, or short arm material below the stalk. Conventional staining, quinacrine fluorescence, C banding and ammoniacal silver staining revealed the apparent same acrocentric short arm variation between patient and one parent in eight families studied. These findings suggest that the satellite variants were truly normal variants and not etiologically related to the developmental disorders seen in the patients.

Child↗
PubMed1979

Partial trisomy of 13(pter to q12) due to 47,XY, + der(13),t(13;22)(q12;q13)mat.

A 36-month-old boy presented with short stature, short neck, shield-shaped chest, and mental retardation. Chromosome analysis showed trisomy for the short arm and the proximal protion of the long arm of chromosome 13 [47,XY, + der(13),t(13;22)(q12;q13)mat]. The patient's mother has a balanced translocation between the long arms of chromosomes 13 and 22 [46,XX,t(13;22)(q12;q13)]. The patient's neutrophils showed an elevated number of nuclear projections and his fetal hemoglobin level was undetectable.

Adult↗
PubMed1979

Hemoglobin polymorphism in Equus przewalskii and E. caballus analyzed by isoelectric focusing.

1. Through the use of isoelectric focusing and peptide analysis, the hemoglobins of Przewalski's horse. Equus przewalskii and the domestic horse, E. caballus have been compared. 2. Przewalski's horses have two separate alpha-globin chain polymorphisms similar to domestic horses. Each hemoglobin phenotype could be accurately determined by isoelectric focusing. 3. Confirmation of the electrofocusing hemoglobin determinations was made by comparison to amino acid composition analyses of purified tryptic peptides and by analysis of the rare hemoglobins phenotypes observed in a family of Norwegian trotting horses. 4. Hemoglobin genotypes of fifteen Przewalski's horses were determined and inheritance of hemoglobin haplotypes has been observed.

Amino Acids↗
PubMed1979

Regional assignment of the steroid sulfatase-X-linked ichthyosis locus: implications for a noninactivated region on the short arm of human X chromosome.

The expression of steroid sulfatase (SS; sterol-sulfatase; sterol-sulfate sulfohydrolase, EC 3.1.6.2), a microsomal enzyme that catalyzes the hydrolysis of a variety of 3beta-hydroxysteroid sulfates, was evaluated in mouse-human hybrid clones. The mouse parental line, A9, was found to have little SS as determined by activity measurements. Human SS can be separated from mouse SS by electrophoresis. Two human fibroblast lines, one carrying an X/13 translocation [46,X,t(X;13)(p22;q12)] and the other carrying an X/20 translocation [46,X,t(X;20)(Xp20q;Xq20p)] were used as the human parental lines. Several independently derived hybrid clones from each of the two fusion experiments were analyzed for the expression of human SS by activity measurements and electrophoresis. Cytogenetic analyses were done on these hybrid clones at the same passage level. The results showed that the expression of human SS in these cell hybrids was concordant only with the presence of the distal half (p22-->pter) of the short arm of the human X chromosome, thus assigning the locus for SS to Xp22-->Xpter. Earlier studies have shown that the deficiency of SS is the basis for the dermatologic condition X-linked ichthyosis, the gene for which is known to be located approximately 10 centimorgans from the Xg blood group locus. The localization of SS on the X chromosome indicates that Xg locus may be on the short arm of X and possibly on its distal half. The Xg locus is thought to escape X-inactivation in man, and recent investigations suggest that the SS locus also escapes X-inactivation. Our results thus provide evidence for the location of an apparently noninactivated site on the distal half of the short arm of the human X-chromosome that contains the locus for SS and possibly the Xg locus.

Chromosome Mapping↗
PubMed1979

Features of trisomy 18 and 18p- syndromes in an infant with 45,XY,i(18q).

An isochromosome for the long arm of chromosome number 18 - 46,XY,i(18q) - was found in an infant who had features of both trisomy 18 and 18p- syndromes. Findings compatible with trisomy 18 included postmature delivery, prominent occiput, severe congenital heart disease, overlapping fingers, and rocker-bottom feet. Those of 18p- syndrome, which frequently resembles Turner syndrome, were downward obliquity to the palpebral fissures, short, webbed neck, low posterior hairline, and widely-spaced nipples. The infant died of heart failure at 3.5 months of age. Parental karyotypes were normal.

Abnormalities, Multiple↗
PubMed1979

Phenotypic variation in two patients with a ring chromosome 22.

Two severely mentally retarded patients with a ring chromosome 22 presented with disparate phenotypes: one patient manifested only minimal dysmorphic features, whereas the other had a distinctive pattern of anomalies consisting of an abnormal skull configuration with mild maxillary hypoplasia, a large nose, thick full lips, a protruding tongue, lymphedema, hypotonia and an unsteady gait. The findings in these and previously reported patients indicate that a ring chromosome 22 is usually associated with moderate to severe mental retardation, with a range of dysplastic features from mild and nonspecific to more marked and distinctive.

Abnormalities, Multiple↗
PubMed1979

The 9p-syndrome.

A 13-year-old boy with 9p- (p22 leads to pter) is reported. He had many features in common with previous 9p- cases, as well as several distinctive features including polydactyly and precocious puberty. Cytogenetic studies revealed a de novo deletion distal to ban 9p22, which was the reported site of chromosome break in 9 of the 10 previous 9p- cases. Evaluation of the human GALT enzyme suggests that its locus is not on the deleted segment.

Abnormalities, Multiple↗
PubMed1979

Two balanced translocations in three generations of a pedigree: t(7;10) (q11;q22) and t(14;21) (14qter to cen to 21qter)1.

A reciprocal chromosome translocation between 7q and 10q and an unrelated Robertsonian translocation involving 14q and 21q were found in a healthy 44-year-old man, in his normal 18-year-old son, and in his mother. They were ascertained through the man's brother, whose grandson has Down's syndrome as a result of an inherited 14q21q translocation. To our knowledge, this is the second report of a karyotype with both reciprocal and Robertsonian translocations in a single subject, and only the fourth report of independently segregating double translocations occurring in more than one generation.

Abortion, Habitual↗
PubMed1979

18p--syndrome resulting from translocation (13a;18q) in a mildly affected adult male.

The patient was a 27-year-old male with short stature, borderline mental deficiency, strabismus, and a short fourth metacarpal. His karyotype showed deletion of the short arm of a chromosome 18 as the result of de novo fusion centric translocation between chromosomes 13 and 18 (45,XY, --13, --18, +t(13;18) (13qter yields cen yields 18qter).

Adult↗