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Biomedical subjects

D O Robinson

Publications and source records attributed to D O Robinson.

At least 37 records · Page 2Linked to original sources
PubMed1999

A molecular and FISH analysis of structurally abnormal Y chromosomes in patients with Turner syndrome.

Fourteen patients with Turner syndrome and a structurally abnormal Y chromosome were analysed by PCR amplification and fluorescence in situ hybridisation for the presence of sequences specific to defined regions of the Y chromosome. Thirteen patients had a mosaic karyotype including a 45,X cell line and one case was non-mosaic in cultured lymphocytes. Ten patients had a pseudodicentric Yp chromosome, two an isodicentric Yq, one a pseudodicentric Yq, and one a derived Y chromosome. Two of the patients with a psu dic(Yp) chromosome had complex karyotypes with more than two cell lines, one of which exhibited five morphologically distinct mar(Y) chromosomes, presumably derived from a progenitor psu dic(Yp). Nine of the ten psu dic(Yp) chromosomes were positive for all Yp and Yq probes used except DYZ1 which maps to Yq12, suggesting a common breakpoint near the Yq euchromatin/heterochromatin boundary. In the three patients with a dicentric Yq chromosome two different breakpoints were observed; in two it was between PABY and the subtelomeric repeat sequence and in one it was between DYZ5 and AMGY in proximal Yp. Our results suggest that the great majority of structurally abnormal Y chromosomes found in Turner syndrome mosaics contain two copies of virtually all of the functional Y chromosome euchromatin.

Chromosome Mapping↗
PubMed1998

Paternal uniparental disomy of chromosome 6 and transient neonatal diabetes mellitus.

Transient neonatal diabetes mellitus occurs in growth-retarded infants, has an incidence of 1 in 400000 live births and has been associated with both paternal uniparental disomy of chromosome 6 and paternal duplications of 6q. We analysed samples from our cohort of patients with transient neonatal diabetes mellitus for uniparental disomy of chromosome 6 using polymorphic microsatellite repeat analysis. We report here the fifth case of paternal uniparental disomy of chromosome 6 associated with classic transient neonatal diabetes mellitus and estimate that uniparental disomy of chromosome 6 accounts for approximately one fifth of cases of transient neonatal diabetes mellitus.

Chromosomes, Human, Pair 6↗
PubMed1997

A small intraexonic deletion within the dystrophin gene suggests a possible mechanism of mutagenesis.

A case of Duchenne muscular dystrophy is described with an unusual mutation consisting of a 17-bp deletion within exon 47 of the dystrophin gene. The sequences on either side of the deletion have a high degree of intrastrand base complementarity. It is hypothesised that the mechanism generating the deletion may have been the formation of hairpin loop structure in a single strand of DNA followed by enzymatic degradation at unpaired regions within the loop.

Algorithms↗
PubMed1997

Aetiopathology and genetic basis of neonatal diabetes.

A British Paediatric Association Surveillance Unit* study of neonatal diabetes determined a national incidence of 1 in 400,000 live births. Additional cases of transient neonatal diabetes were collected retrospectively. Most cases were of low birthweight at term: none had evidence of an autoimmune aetiopathogenesis. The median requirement for exogenous insulin treatment was three months. A significant number of cases developed type 2 diabetes in later life. Three of the 11 cases were found to have paternal uniparental isodisomy of chromosome 6. A further patient carried an unbalanced duplication of 6q 22-23, inherited from the father, which localised a potentially imprinted gene for diabetes to this region. The fact that low birthweight predisposes to type 2 diabetes in later life is well established, but a genetic defect that may relate both to intrauterine growth failure and the development of type 2 diabetes in later life has now been identified.

Aneuploidy↗
PubMed1996

Further evidence for an imprinted gene for neonatal diabetes localised to chromosome 6q22-q23.

Transient neonatal diabetes mellitus (TNDM) is a rare form of childhood diabetes which usually resolves in the first 6 months of life but which predisposes to type 2 diabetes of adult onset. We recently reported paternal uniparental isodisomy of chromosome 6 (UPD6) in two children with TNDM and proposed that there may be an imprinted gene important in the aetiology of diabetes on chromosome 6. We now describe two unrelated families which independently suggest that the gene is imprinted, is paternally expressed and maps to 6q22-q23. One family has a duplication while the other, with familial TNDM, shows linkage to a marker in this region.

Adult↗
PubMed1996

Development of a hearing performance standard for law enforcement officers.

A hearing performance standard for new police officer candidates in the State of Michigan was developed by a task force consisting of the authors and four members of the Michigan Law Enforcement Officers Training Council. Ratings of the importance of hearing sensitivity and speech intelligibility in performing each of 135 specific job tasks formed the basis for pass-fail criteria. The standard, described in this report, includes specifications for unaided and aided hearing performance, types of hearing assessment measures, hearing measurement procedures, and the appropriate examining professional. The authors believe that the standard provides an appropriate accommodation to hearing-impaired law enforcement officer candidates with respect to The Americans with Disabilities Act.

Hearing↗
PubMed1995

Fluorescence in situ hybridisation studies provide evidence for somatic mosaicism in de novo dystrophin gene deletions.

The fluorescence in situ hybridisation (FISH) technique was tested for its ability to detect somatic mosaicism in mothers of isolated deletion cases of Duchenne/Becker muscular dystrophy. A control female with known germline and somatic mosaicism was examined, and both the normal cell line and the carrier cell line were detected. Subsequent FISH analysis of three other mothers of boys with apparent de novo dystrophin gene deletions revealed a second patient with a high level of somatic mosaicism, suggesting that a proportion of de novo dystrophin gene deletions occur as mitotic errors early in development rather than as meiotic errors during gametogenesis.

Cells, Cultured↗
PubMed1994

Germline and somatic mosaicism in a female carrier of Duchenne muscular dystrophy.

The family of a male with Duchenne muscular dystrophy (DMD) and a deletion within the dystrophin gene has been studied. Polymerase chain reaction analysis of ectopic mRNA from peripheral blood T+B lymphocytes and the use of (CA)n repeat polymorphisms in and around the deleted region showed the proband's mother to be both a germline mosaic and a somatic mosaic for the deletion seen in her son. The mutation therefore occurred as a mitotic event early in embryogenesis.

Child, Preschool↗
PubMed1990

A cytogenetic and molecular reappraisal of a series of patients with Turner's syndrome.

The results of a cytogenetic and molecular reinvestigation of a series of 52 patients with Turner's syndrome are reported. No evidence of Y chromosome material was found among the patients with a 45,X constitution but two patients were found to have a cell line with a r(Y) chromosome which was previously thought to be a r(X). The parental origin of the single X in the 45,X patients was maternal in 69% and paternal in 31%, a similar ratio to that seen among spontaneously aborted 45,X conceptuses. This suggests that X-chromosome imprinting is not responsible for the two grossly different phenotypes associated with a 45,X chromosome constitution. Approximately half of the structurally abnormal X chromosomes were maternal in origin and half paternal. This observation is consistent with either a meiotic or post-zygotic mitotic origin and at variance with the predominantly paternal origin reported for autosome structural abnormalities.

Adolescent↗
PubMed1988

Infant tympanometry: differential results by race.

Black (N = 63) and White (N = 74) infants, ages 6-13 months, were screened by tympanometry for signs of middle ear dysfunction. More White infants (57%) than Black (33%) failed initial screening (p less than .01). Retest of initial failures after a minimum 6-week interval showed an overall reduction in failure rates, but the significant (p less than .05) racial effect was still obtained. Implications of these findings for the clinician are discussed.

Acoustic Impedance Tests↗
PubMed1984

Racial differences in tympanometric results.

The occurrence of failed tympanometric screenings in 253 middle-class preschool children, ages 30-48 months, was examined. Black children showed a significantly (p less than .05) lower incidence of failure (23% compared to 38% for White children); this pattern was attributable primarily to differential rates of failure for older children (greater than or equal to 36 months). Explanations for this difference are discussed.

Acoustic Impedance Tests↗
PubMed1981

High-frequency Bekesy audiometry: III. Reliability and validity revisited.

Normal-hearing young adults (N: 30) produced 3 fixed-frequency monaural audiograms by Bekesy tracking on a Grason-Stadler E-800 audiometer (modified for high frequencies) for pulsed pure tones in 2-kc/s steps progressively from 7-19 kc/s. The earphone was not moved between one pair of audiograms but was removed and replaced between another pair. After 1 mo, 16 Ss returned for retest on the HF E-800 audiometer and on a similar audiometer using the conventional Method of Limits. Maximum group mean retest HTL differences approximated 5 db. Statistical analysis indicated that the arrays of HTLs within and across sessions were equivalent. Reliability and validity coefficients were high and significantly different from zero. It was concluded that the HF E-800 could with such Ss be used with some confidence to assess high-frequency sensitivity.

Adult↗
PubMed1979

Models of a heroin epidemic.

Heroin addiction may be considered an epidemic disease that is communicated by people who are addicted to the drug. It has been suggested that the most recent epidemic in the United States had its peak incidence in 1969. The age of heroin addicts entering treatment has increased systematically from 1973 to 1976 at a rate of less than one year of age per calendar year. This pattern is consistent with a moderate decline in a national heroin epidemic or a geographical migration of the epidemic from more to less populated areas. There are also seasonal trends in the age of admission to treatment.

Adolescent↗
PubMed1979

Cocaine: magical drug or menace?

Cocaine has attracted much attention as a recreational drug and some advocates have acclaimed it as both pleasurable and safe. This paper reviews the available evidence concerning the drug's physiological and psychological safety. Few deaths are attributed to cocaine, but its use is presently restricted by very limited supplies. Use of the drug may possibly result in liver and respiratory problems and may lead to paranoid psychotic conditions. There are many deficiencies in our knowledge of the effects of this drug.

Aggression↗