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Biomedical subjects

D Anderson

Publications and source records attributed to D Anderson.

At least 577 records · Page 32Linked to original sources
PubMed1981

Fractionated dose studies with X-rays and various alkylating agents in P388 mouse lymphoma cells.

The fractionated dose technique has been used in P388F cells to examine the effects of X-rays and four alkylating agents on survival and induction of 5-iodo-2-deoxyuridine (IudR) resistant variants. Fractionation intervals up to 5 1/2 h were used for X-rays and for the alkylating agents up to 192 h. Fractionation of the X-ray dose resulted in a sparing effect for survival and variant induction. A sparing effect was also observed for survival after treatment with alkylating agents. However, variant frequencies were observed as large as or greater than those produced by the full doses of alkylating agents. For such agents this would suggest that survival and variant induction are independent events. Differences in the effects of X-rays and alkylating agents cannot be explained by differences in growth rate or the recovery of viability after treatment.

Alkylating Agents↗
PubMed1981

Anti-digoxin antibody in digoxin intoxication.

This study was conducted to investigate the action of anti-digoxin antibody in digoxin intoxication. Anti-digoxin antibody was raised in sheep and administered to six dogs following intravenous infusion of digoxin (0.04 or 0.16 mg/kg body weight), either as whole serum or as partially purified gamma globulin. Plasma and urine digoxin levels, both bound and free, were determined on serial samples. Myocardial samples were analysed for digoxin content. Comparisons were made with six dogs given digoxin but no antibody. The results indicate that anti-digoxin antibody is effective through inactivation of digoxin in myocardium and removal of digoxin from myocardium into plasma. Loss of digoxin in urine is not responsible for toxicity reversal.

Animals↗
PubMed1981

Evaluation of the polyethylene glycol precipitation method for the estimation of high-density lipoprotein cholesterol.

Treatment of fresh sera with polyethylene glycol 6000 at a final concentration of 100 g/l produced selective precipitation of low-density lipoproteins with only traces of contamination with high-density lipoproteins, as determined by electroimmunoassay using antisera to human alpha1-lipoprotein and human beta-lipoprotein. Supernatants collected for high-density lipoprotein-cholesterol estimation were free from low-density lipoproteins. Precipitates sedimented readily from specimens with high triglyceride contents, and secondary precipitation during enzymatic cholesterol determinations was absent. Values obtained by this method correlated well with those obtained by precipitation of low-density lipoproteins with heparin and manganous ions at concentrations optimal for discrete of lipoprotein classes (r = 0.975; p less than 0.001).

Chemical Precipitation↗
PubMed1981

Relationship of steroid receptor, cell kinetics, and clinical status in patients with breast cancer.

The fractions of cells in the different phases of the cell cycle were determined by flow cytometry in 70 human breast tumors and six human benign breast tissues. This procedure showed that 44% of the tumors and none of the benign tissues were aneuploid as determined by mixing experiments using normal peripheral blood as a standard for DNA content per nucleus. The mean percent S-phase fraction (% S) values +/- S.D. for benign and malignant tissues were 6.9 +/- 1.6 and 13.7 +/- 6.5, respectively. By our procedure, aneuploid tumors seem to have significantly higher mean % S value than do diploid tumors. Breast cancer tissue which contained steroid receptors had a mean % S value of 11.3, while those tumors which had neither the estrogen nor progesterone receptors had a mean % S value of 17.1 (p less than 0.01). The estrogen receptor status had a better inverse relationship to the cell kinetic data than did the progesterone receptor status. The use of molecular forms of the steroid receptor was of some assistance in improving the inverse relationship between cell kinetics and steroid receptor status. A trend was observed between lack of steroid receptors and higher probability of the tumor being aneuploid. From the limited clinical data, there was no relationship between cell kinetic and aneuploid data with respect to nodal status, metastatic disease, and menopausal status. The possible use of these data is discussed.

Aneuploidy↗
PubMed1981

Meningioma and the ophthalmologist: diagnostic pitfalls.

In seven patients with intracranial meningioma whose presenting signs and symptoms were ophthalmologic the underlying problem was initially misdiagnosed. Three patients had sphenoidal meningiomas with compression of the anterior visual pathways, but the initial diagnoses were acute optic neuritis, chronic optic neuritis and glaucoma. Two other patients had large frontal meningiomas causing in one case unilateral pain and swelling of the upper lid plus ptosis and hypotropia, and in the other case bilateral frontal morning headaches and intermittent blurring of vision in one eye; they were thought to have a frontal lobe osteoma and migraine respectively. A sixth patient had a large parietal meningioma causing unilateral papilledema in an eye with a corneal graft; the papilledema was not initially recognized because of severe astigmatism in that eye. The last patient had an occipital meningioma that had caused a fixed homonymous field defect and many years of "classic migraine".

Adult↗
PubMed1980

Melittin forms crystals which are suitable for high resolution X-ray structural analysis and which reveal a molecular 2-fold axis of symmetry.

Melittin is the principal protein component of bee venom and is believed to function as a lytic agent. In aqueous salt solution, it is a tetramer of identical peptides, each with 26 amino acid residues. Although its amino acid composition is unusually nonpolar, and although it is believed to integrate into membranes while lysing cells, melittin is water-soluble at neutral pH. Two crystal forms have been grown from solutions containing ammonium sulfate and sodium formate, and their x-ray diffraction patterns indicate that the melittin tetramer contains at least one 2-fold axis of rotation. Both crystal forms are suitable for high resolution x-ray structural studies. Moreover, both crystals bind several heavy atoms as judged by changes in buoyancy, so that phase determination by the method of isomorphous replacement is possible. Crystallized melittin retains its lytic activity even under the conditions of crystallization (about 70% saturated ammonium sulfate).

Animals↗
PubMed1980

An ecological analysis of A-B and its relationship to field dependence.

Because of conceptual and methodological problems of the A-B categorization, several authorities (Gomes-Schwartz, Hadley, & Strupp, 1978; Stephens, Shaffer & Zlotowitz, 1975) have suggested that a moratorium on A-B research deserves serious consideration. In anticipation of this possibility, and to attempt to clarify the confusing findings with regard to the nature of A-B and the relationships of A-B and Field Dependence, the authors initiated this study of the ecological framework of a psychiatric ward and the role characteristics of both staff and patients (N = 99). The results of the study supported the two major hypotheses that were derived from a functional analysis of the demand characteristics for both patients and staff on an inpatient psychiatric unit. First, it was found that the staff scored higher on type A characteristics than on type B characteristics and, second, it was found that the patients scored higher on type B characteristics than on type A characteristics.

Female↗
PubMed1980

Chromosomal analyses in vinyl chloride exposed workers. Results from analysis 18 and 42 months after an initial sampling.

In a previous study (Purchase et al., Mutation Res., 57 (1978) 325-334) it was reported that 57 workers occupationally exposed to vinyl chloride had an increase in the incidence of chromosomal abnormalities in their lymphocytes by comparison with 24 control workers. Since that time (July 1974) threshold limit values for vinyl chloride and plant exposure levels have been reduced. In the present study, 2 further samples from the same population of workers have been analysed for chromosomal aberrations 18 and 42 months after the initial sampling. At 18 months, 21 VC workers and 6 on-site controls were investigated as were 23 workers and 8 on-site controls at 42 months. In the second sampling there was a tendency to an increase in chromosomal abnormalities of VC-exposed workers except in those people who had changed occupation. By the third sampling, however, there was a decrease by comparison with previous samplings and the levels of abnormalities had returned to values similar to those of the controls. Thus, reduction in exposure to vinyl chloride is accompanied by a reduction in the chromosomal abnormalities to levels indistinguishabe from those of controls.

Adult↗
PubMed1980

The effect of solvents upon the yield of revertants in the Salmonella/activation mutagenicity assay.

The effects of dimethylsulphoxide and acetone have been investigated in the Salmonella/activation mutagenicity assay using 2-aminoanthracene and benzo(a)pyrene as test compounds. Varying mutagenic responses were found with the solvents mutagenic responses were found with the solvents after treatment of the bacteria with 2-aminoanthracene. This was observed in two laboratories. Differences were not as evident after treatment with benzo(a)pyrene. In addition, different amounts of dimethylsulphoxide were used to dissolve amounts of dimethylsulphoxide were used to dissolve 2-aminoanthracene and varying mutagenic responses were obtained. These observations suggest that the choice and amount of solvent for individual test compounds may be critical in terms of determining a mutagenic response.

Acetone↗