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Biomedical subjects

A Carothers

Publications and source records attributed to A Carothers.

26 records · Page 2Linked to original sources
PubMed1991

Radiation dosimetry by automatic image analysis of dicentric chromosomes.

A system for scoring dicentric chromosomes by image analysis comprised fully automatic location of mitotic cells, automatic retrieval, focus and digitization at high resolution, automatic rejection of nuclei and debris and detection and segmentation of chromosome clusters, automatic centromere location, and subsequent rapid interactive visual review of potential dicentric chromosomes to confirm positives and reject false positives. A calibration set of about 15,000 cells was used to establish the quadratic dose response for 60Co gamma-irradiation. The dose-response function parameters were established by a maximum likelihood technique, and confidence limits in the dose response and in the corresponding inverse curve, of estimated dose for observed dicentric frequency, were established by Monte Carlo techniques. The system was validated in a blind trial by analysing a test set comprising a total of about 8000 cells irradiated to 1 of 10 dose levels, and estimating the doses from the observed dicentric frequency. There was a close correspondence between the estimated and true doses. The overall sensitivity of the system in terms of the proportion of the total population of dicentrics present in the cells analysed that were detected by the system was measured to be about 40%. This implies that about 2.5 times more cells must be analysed by machine than by visual analysis. Taking this factor into account, the measured review time and false positive rates imply that analysis by the system of sufficient cells to provide the equivalent of a visual analysis of 500 cells would require about 1 h for operator review.

Cells, Cultured↗
PubMed1991

Analysis of the origin of Turner's syndrome using polymorphic DNA probes.

Thirty-four families with a child or fetus with Turner's syndrome were studied using a series of polymorphic DNA probes. Analysis of the origin of the normal X chromosome was possible in all cases. In 16 families with 45,X (four fetuses and 12 livebirths), the observed X was maternal in each case, indicating a preferential loss of the paternal sex chromosome at, or before, conception. In the remaining 18 families with a variety of karyotypes, but especially in those where the child had an isochromosome of Xq or a ring X, there was again a strong tendency for the normal X to be maternal. Analysis of parental ages was performed with known origin of each abnormality, but no evidence for an increased or decreased parental age effect was detected.

Adult↗
PubMed1990

Association within a family of a balanced autosomal translocation with major mental illness.

282 pedigrees in the MRC Cytogenetics Registry, Edinburgh, with familial autosomal anomalies were examined for the presence of associated mental illness. In one large pedigree there were 23 cases of mental and/or behavioural disorders meeting Research Diagnostic Criteria. 34 of the 77 family members available for cytogenetic analysis carried a balanced translocation t(1:11) (q43,q21). Psychiatric diagnoses had been recorded for 16 of the 34 members with the translocation compared with only 5 of the 43 without it. The lod scores (against chance linkage of the translocation with mental illness) were greatest when the mental disorders in the phenotype were restricted to schizophrenia, schizoaffective disorder, recurrent major depression, and adolescent conduct and emotional disorders. Although the mental illness in this family may not be typical of that in the general population, the findings suggest that the q21-22 region of chromosome 11 may be a promising area to examine for genes predisposing to major mental illness.

Adolescent↗
PubMed1984

Karyotyping and identification of human chromosome polymorphisms by single fluorochrome flow cytometry.

Frequency distributions of fluorescence intensity of ethidium bromide stained human chromosomes from nine phenotypically normal males are cross correlated and autocorrelated following repeated flow cytometric measurements. It is shown that each individual donor produces a fluorescence profile which is both visually and numerically different from those of other individuals in the set. The wide variety of chromosome heteromorphisms which occur to varying degrees for chromosomes 1, 9, 13, 14, 15, 16, 21, 22 and Y give rise to the uniqueness of a given fluorescence profile. Estimates of chromosome heteromorphisms for each individual in the set were made and then compared with parallel results obtained from inspection of Q-banded and C-banded conventional metaphase preparations. Fluorescence profiles identifiable with each individual were also obtained for Hoechst 33258 stained chromosomes.

Chromosome Banding↗
PubMed1981

Parotid venous ectasia.

An unusual recurring mass presented in the parotid region in a young woman. The presentation of the mass was unusual in that it varied with the positioning of the patient's head and with exertional and emotional activity. Prior surgical attempts at cure were unsuccessful. Biplanar subtraction radiographic techniques were used to pinpoint the anatomical problems. This lesion is a vascular anomaly, which requires specific attention to its morphology in order to effect a permanent cure. This case of parotid venous ectasia with its unusual symptom complex was successfully treated, and more than four years have passed without recurrence.

Adult↗
PubMed1979

Radiation-induced chromosome aberrations in nuclear-dockyard workers.

The incidence of chromosome aberrations in peripheral blood lymphocytes of 197 dockyard workers has been followed over a 10-yr period. These workers were exposed to mixed neutron-gamma radiation during the refuelling of nuclear reactors, but most exposures were below the internationally accepted maximum permissible level of 5 rem per yr. There was a significant increase in chromosome damage with increasing exposure; aberration frequency was a linear function of dose and was unfluenced by age and time of blood sampling after exposure.

Age Factors↗
PubMed1978

Orbitofacial wounds and cerebral artery injuries caused by umbrella tips.

Penetrating orbitofacial wounds inflicted by the sharp metal tips of umbrellas may go unrecognized. This type of injury is not generally appreciated as having fatal consequences. Immediate neurologic and radiologic evaluations are diagnostic. The value of computerized tomography and cerebral angiography is stressed.

Adult↗