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Biomedical subjects

R R Weichselbaum

Publications and source records attributed to R R Weichselbaum.

At least 307 records · Page 17Linked to original sources
PubMed1980

X-ray sensitivity of fifty-three human diploid fibroblast cell strains from patients with characterized genetic disorders.

The in vitro response of 53 human diploid fibroblast strains to X-irradiation was studied using a clonogenic survival assay. The strains, derived from patients with a variety of characterized clinical conditions, most with a genetic component, ranged in Do (a measure of the slope of the survival curve) from 43 to 168 rads. The mean Do's of six strains from normal individuals was 140 to 152 rads, with an overall range, based on the extremes of their standard errors, of 128 to 164 rads. Three-quarters of the strains studied fell within this range. Strains identified as sensitive came from patients with ataxia telangiectasia, progeria, the two genetic forms of retinoblastoma, and partial trisomy of chromosome 13. No marked radiosensitivity was found among strains derived from patients with a number of other conditions associated with a predisposition to malignancy.

Adolescent↗
PubMed1979

DNA repair in a Fanconi's anemia fibroblast cell strain.

DNA repair and colony survival were measured in fibroblasts from a patient with Fanconi's anemia, HG 261, and from normal human donors after exposure of these cells to the cross-linking agent mitomycin C, X-rays or ultraviolet light. Survival was similar in HG 261 and normal cells after X-ray or ultraviolet radiation, but was reduced in the Fanconi's anemia cells after treatment with mitomycin C. The level of DNA cross-linking, as measured by the method of alkaline elution, was the same in both cell strains after exposure to various doses of mitomycin C. With incubation after drug treatment, a gradual decrease in the amount of cross-linking was observed; the rate of this apparent repair of cross-link damage was the same in both normal and HG 261 cells. The rejoining of DNA single strand breaks after X-irradiation and the production of excision breaks after ultraviolet radiation were also normal in HG 261 cells as determined by alkaline elution.

Anemia, Aplastic↗
PubMed1979

Interstitial deletion of chromosome 13 and associated congenital anomalies.

An interstitial deletion of chromosome 13 with breakpoints at 13q22 and 13q32 is presented. The clinical findings associated with this deletion are discussed in relation to the correlations of specific chromosomal bands with constellations of congenital defects as described by Niebuhr and Ottosen (1973), Niebuhr (1977). Lewandowski and Yunis (1975), and Noel et al. (1976).

Abnormalities, Multiple↗
PubMed1979

Uveal malignant melanoma in three generations of the same family.

Three patients in three successive generations from the same family had choroidal malignant melanoma. The third generation patient had multiple primary malignancies; his siblings also had multiple malignancies. Chromosome studies of the third generation patient revealed no abnormality. To the best of our knowledge, this is the second such pedigree reported.

Adult↗
PubMed1979

New findings in the chromosome 13 long-arm deletion syndrome and retinoblastoma.

New clinical and pathologic findings in patients with deletion of the long arm of chromosome 13 (13q-) include optic nerve hypoplasia and retinal dysplasia. Fibroblasts derived from patients with a 13q- syndrome with and without retinoblastoma, as well as from familial and sporadic retinoblastoma, are a useful model for the study of genetic susceptibility to the development of spontaneous and radiation-induced cancers. Fibroblasts from patients with hereditary retinoblastoma appear more radiosensitive than fibroblasts from patients with sporadic retinoblastoma or normal control patients.

Abnormalities, Multiple↗
PubMed1979

Retinoblastoma, chromosome 13, and in vitro cellular radiosensitivity.

Five diploid fibroblast strains from patients with deletions mapping in the long arm of chromosome 13 and three strains bearing partial trisomies of chromosome 13 were assayed for clonogenic survival following X-irradiation. Results of these experiments suggest the existence of a region on 13q14 which is related to increased sensitivity to cell killing in vitro by X-rays. This locus seems to be distinct from but close to the retinoblastoma locus, which has been associated with the same band.

Chromosome Deletion↗
PubMed1979

Defective reactivation of ultraviolet light-irradiated herpesvirus by a Bloom's syndrome fibroblast strain.

We have used the technique of host cell reactivation of UV-irradiated herpes simplex virus type 1 as a measure of the repair capacity of three Bloom's syndrome skin fibroblast strains. At low multiplicity of infection (less than 6 x 10(-4) plaque-forming unit/cell), reactivation of the virus by the Bloom's syndrome strains was indistinguishable from that by normal strains. Reactivation at higher multiplicities was measured using an infectious centers assay. At 3 plaque-forming units/cell, survival of UV-irradiated herpes simplex virus was higher in all cell strains as a result of the multiplicity reactivation effect. This effect was, however, much smaller in one Bloom's syndrome strain, GM1492, than in either the normal strains or the other Bloom's syndrome fibroblasts. The defect in GM1492 was manifest only at relatively high multiplicates of infection. Thus, at 0.01 plaque-forming unit/cell, the GM1492 strain appeared normal, using the infectious centers assay. Clonal survival of the UV-irradiated GM1492 fibroblasts was also normal. Caffeine at 4 mM had little effect on either virus or cell survival following UV irradiation. The results indicate that the Bloom's syndrome strain GM1492 may be deficient in one of the cellular functions responsible for the multiplicity reactivation effect. These effects include complementation and recombinational events. Alternatively, the GM1492 strain may have a defective UV repair system which becomes saturated at high levels of damage.

Caffeine↗
PubMed1979

Cell biological effects of total body irradiation on growth and differentiation of acute myelogenous leukemia cells compared to normal bone marrow.

Radiation therapy is used as total body treatment in preparation of the acute myelogenous leukemia (AML) patient for bone marrow transplantation. Many AML patients will have residual leukemia cells at the time of total body irradiation (TBI). In the present study, the effect of TBI on leukemic myeloid cells was compared to the effect on normal marrow granulocytic stem cells (CFUc) in vitro. Little difference from that of normal CFUc was found in the radiosensitivity of two mouse myeloid leukemia cell lines. The effect of TBI on growth of WEHI-3 or J774 cells in millipore diffusion chambers was stimulatory. These AML cell lines as well as others derived from Friend or Abelson virus infected in vitro long term mouse marrow cultures showed some morphologic differentiation by 7 days growth in diffusion chambers in irradiated heterologous rat hosts, but immature cells predominated by day 21. Thus, evidence in murine models of AML indicates that residual AML cells surviving chemotherapy will show no greater susceptibility to radiation killing compared to normal stem cells and will rapidly repopulate the irradiated host.

Animals↗
PubMed1978

X-ray sensitivity of diploid fibroblasts from patients with hereditary or sporadic retinoblastoma.

Fibroblasts derived from patients with hereditary retinoblastoma appear to be more sensitive to the lethal effects of x-rays than do fibroblasts from patients with sporadic retinoblastoma or normal controls. A defect in DNA repair is postulated to account for the high incidence of second tumors in these patients. Retinoblastoma appears to be an interesting model for the study of genetic susceptibility to the development of spontaneous or radiation-induced tumors.

Cells, Cultured↗