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Biomedical subjects

R S Anderson

Publications and source records attributed to R S Anderson.

At least 91 records · Page 5Linked to original sources
PubMed1983

Activation of mammalian carcinogens to bacterial mutagens by microsomal enzymes from a pelecypod mollusk, Mercenaria mercenaria.

Several kinds of neoplastic diseases have been described in mollusks collected from the field. The etiology of these lesions is unknown; however, the involvement of chemical carcinogens has been suggested. Experimental models for chemically-induced neoplasia in bivalves have yet to be developed. We have obtained data which suggest that aromatic amines may be more appropriate candidates than polycyclic aromatic hydrocarbons for putative molluscan carcinogens. Digestive gland enzymes from a bivalve mollusk, Mercenaria mercenaria, were found to be able to convert aromatic amines to frameshift mutagens as detected by the Ames Salmonella tester strains. Extensive mutagenesis was obtained with 2-aminoanthracene, 2-aminofluorene, 2-acetylaminofluorene and 4-amino-trans-stilbene which are all mammalian procarcinogens. Mutagenic activation of benzo[a]pyrene and 3-methylcholanthrene was minimal. Low levels of aromatic amine-activating enzyme(s) were found in all tissues examined, but activity was greatest in the digestive gland. Enzymatic activity was heat-labile, NADPH-dependent, and apparently not inducible by polychlorinated biphenyls (Aroclor 1254).

Amines↗
PubMed1983

Observations on the cytochemistry of the hemocytes of an insect, Galleria mellonella.

A number of cytochemical parameters of the hemocytes of larval Galleria mellonella, an insect frequently used as a model by comparative cellular immunologists, are described. Cytochemical methods were used to quantify hemocyte granule-associated components, the results are compared to those obtained for leukocytes from higher animals. Granulocytes contained a population of nonlysosomal granules rich in mucopolysaccharide not seen in plasmatocytes. The numbers and dimensions of these granules showed a positive correlation to cell size, probably reflecting a developmental sequence in granulocyte maturation. Both granulocytes and plasmatocytes had other granules containing the typical lysosomal enzymes, acid phosphatase, beta-glucuronidase, esterase, and lysozyme. The nonlysosomal enzyme alkaline phosphatase was not found in Galleria hemocytes; it is also absent from vertebrate monocytes, macrophages, and immature polymorphonuclear leukocytes. Insect hemocytes appear to lack certain components of antibacterial systems typical of mammalian blood cells, such as H2O2-generating systems, cationic proteins, and myeloperoxidase. The bactericidal mechanisms of hemocytes probably involve lysozyme, as well as other biologically active cellular and humoral factors unique to insects.

Animals↗
PubMed1983

Influence of selenite and fourteen trace elements on cataractogenesis in the rat.

The purposes of these experiments were to measure the influence of 14 trace elements on cataractogenesis and to test if these trace elements could prevent cataracts induced by selenium. On days 5-9 postpartum, suckling white rats received daily subcutaneous injections of either selenium (0.15 mumoles Se, as Na2SeO3, per pup) or selenium plus one of 14 other trace elements (separate subcutaneous injection) at one to five times the molar concentration of selenium. The frequency and severity of cataracts at three locations in the lens were assessed by slit-lamp examination on day 26-28 postpartum. Seven ions were found to be effective in preventing selenium-induced cataracts (% protection): mercuric (100%), silver (80%), cyanide (75%), arsenite (75%), cadmium (60%), and cupric (44%). Tellurite ion offered only 20% protection, while ferrous, zinc, lead, chromic, molybdate, tungstate, and vanadate ions provided no protection against selenium-induced cataract. No significant differences were found between the concentration of selenium in the lenses of control and cataractous lenses when measured approximately three weeks after selenium injection. Except for selenium, none of the trace minerals alone caused cataracts under our experimental conditions. In addition to subcutaneous injection of selenium, oral administration of this element was also found to cause cataract. It was concluded that among the ions studied, selenite was a powerful and rapid promoter of nuclear cataract formation, and that the protection ions may serve as useful probes for elucidating the mechanism of selenium-induced cataracts.

Administration, Oral↗
PubMed1982

Routine real-time scanning at the first hospital visit.

All patients presenting at one consultant booking antenatal clinic had a routine real-time ultrasonic scan. The purpose was to study the accuracy of the technique, the additional work involved and the clinical benefit. All scans were performed by one operator. The average time per scan was 6 min compared with 15 min for each B scan. When gestation assessed by scan differed from gestation assessed by menstrual dates or clinical examination, an independent assessment was made after birth. There was a marked decrease in utilization of B-scanning facilities. Routine real-time scanning at the first visit was a reliable method of assessing gestation in 94% of patients.

Female↗
PubMed1981

The mitochondrial genome is large and variable in a family of plants (cucurbitaceae).

The genome sizes of mitochondrial DNA from darkgrown (etiolated) shoots of several higher plants were determined by reassociation kinetics and restriction analysis. Kinetic complexities obtained from reassociation kinetics measured spectrophotometrically indicate a mitochondrial genome size of 1600 Md for muskmelon, 1000 Md for cucumber, 560 Md for zucchini squash and 220 Md for watermelon (four species in the cucurbit family), as well as 240 Md for pea and 320 Md for corn. The kinetic curves also reveal the presence (except in corn) of sequences of a few magadaltons of complexity, reiterated about 10-50 times and representing 5%- 10% of the DNA in each mitochondrial genome. Molecular weight summation of fragments resulting from digestion with restriction endonucleases Sal I and Kpn I give genome size estimates similar to those obtained from reassociation kinetics, except for muskmelon and cucumber, for which the large number of fragments of similar size limits our estimate to at least 500 Md. The number of mitochondrial genomes per diploid cell is estimated to be about 110 to 140 for muskmelon, zucchini and watermelon. We consider the possible evolutionary mechanisms by which the mitochondrial genome has grown within the cucurbit family and the possible reasons for the existance of a seven to eight-fold range in mitochondrial genome size among such closely related species.

DNA Restriction Enzymes↗
PubMed1981

Effect of vitamin A deficiency on glycosylation of rat serum alpha 1-macroglobulin.

We previously reported that synthesis of the serum glycoprotein alpha 1-macroglobulin (alpha 1-M) was decreased in vitamin A-deficient rats. In a reexamination of this conclusion we have shown that the primary synthetic change, reflected by labeled glucosamine uptake, was an underglycosylation which initially has no effect on the glycoprotein's concentration in serum. The severity of this lesion developed progressively and was independent of the glycosylation of total serum glycoprotein, at least up to 11 days after onset of the deficiency. Less glucosamine was demonstrated chemically in a alpha 1-M purified from rats in the first week of deficiency; alpha 1-M from more severely deficient rats showed significant depressions of mannose, galactose, and glucosamine.

Animals↗
PubMed1980

Mechanisms of Giemsa banding. II. Giemsa components and other variables in G-banding.

We investigated the capability of individual thiazins in Giemsa mixture (methylene blue and azures A, B, and C) and of two related dyes (toluidine blue and thionin) to produce G-banding. We further tested the effects of variations of buffer composition and concentration, dye concentration, and staining time. G-banding was produced by all of the dyes at low concentrations, although differences were noted. Overall, methylene blue and azure B produced the best banding, azures A, C, and toluidine blue produced moderately good banding, and thionin produced poor banding. This order did not appear to be altered essentially by different treatments. The optimal conditions for G-banding for all dyes and treatments included the use of (1) 0.025-0.05 M phosphate buffer, (2) dye concentrations of 0.002%--0.005%, and (3) staining times of 6--15 min.

Azure Stains↗
PubMed1980

Inhibition of Potato Tuber Invertase by an Endogenous Inhibitor: EFFECTS OF SALTS, pH, TEMPERATURE, AND SUGARS ON BINDING .

Binding between potato tuber invertase and its endogenous inhibitor followed second-order reaction kinetics. Binding rates were diminished by the presence of various inorganic salts, MgCl(2) being especially effective. This effect of MgCl(2) was used in binding rate studies by adding the salt with sucrose to reduce binding during assay of previously unbound activity. The optimal pH for binding was about 4.8, similar to the optimal pH for catalytic activity of invertase. The optimal temperature for binding was about 45 C, approximately 5 C less than the optimum for catalytic activity. Sucrose at concentrations as low as 2 millimolar slowed binding; reducing sugars had little or no effect on binding or on catalytic activity.

Journal Article↗
PubMed1980

Cataract-webbed trait in Peromyscus. II. Biomicroscopy and histology of eyes.

A longitudinal biomicroscopic study of lenses and fundi of over 2,000 Peromyscus maniculatus (deer mice) which have cataracts as an autosomal recessive trait has been correlated with histologic development of cataracts. By selective breeding, early-onset cataracts (Type I), which are frequently associated with abnormal closure of the fetal fissure and hyaloid vascular abnormalities, have been separated from later-onset (Type II) cataracts, which are more heterogeneous. Type I cataracts occur in syndactylous deer mice, develop rapidly, and histologically may show backward migration of disrupted lens bow cells before lens opacity is apparent biomicroscopically. Posterior subcapsular cataracts then develop and spread centrally and inferonasally to the equatorial area and then to the entire equator. The nucleus opacifies in either a "shell" pattern or as isolated dots. Anterior cortical opacification progresses to mature cataract. Histologically, abnormal migration and proliferation of lens epithelium and enlargement and vacuolar degeneration of the basal (posterior) process of cortical lens fibers are early changes in Type I cataracts. Disruption of the lens bow with failure of differentiation and inward turning of lens epithelium to become lens fibers occurs concurrently. Type II cataracts may follow the developmental pattern of Type I but are rarely associated with severe hyaloid vascular abnormalities and progress more slowly. About 6% of animals develop diabetes, which is not associated with the cataract-webbed trait.

Animals↗
PubMed1980

Ultrastructure and acid phosphatase activity in hereditary cataracts of deer mice.

Lenses of cataract-webbed (cw) Peromyscus maniculatus were examined by electron microscopy and compared to age-matched normal deer mouse lenses. Precataractous lenses of offspring of cw/cw matings were examined and compared to early cataract development in the opposite eye of the same animal. The earliest ultrastructural change leading to disturbance of lens transparency was cell fusion and formation of fiber cell syncytia in the posterior subcapsular region. Fiber cells lost their regular hexagonal packing. Small osmiophilic densities on the plasma membrane coincided with many of the sites of cell confluency. Larger osmiophilic whorls were usually localized in ball-and-socket interlocking junctions after the opacity spread. Epithelial cells from the nasal ventral equator migrated to the posterior pole. Later when underlying cortical fibers ruptured, the migrated cells phagocytized lens proteins and incorporated them in acid-phosphatase positive lysosomes. Fiber cells 3 to 20 layers deep in the cortex of normal and cataractous lenses had acid phosphatase reaction product coating the plasma membrane; the possible significance of this finding is discussed. We postulate that this hereditary cataract results from a defect in turnover and control of plasma membrane components.

Acid Phosphatase↗
PubMed1979

Recent evidence for the participation of vitamin A in glycoprotein synthesis.

Recent evidence supports the concept that vitamin A plays some role in glycoprotein synthesis in a large-variety of tissues examined. Its involvement may be through participation of a retinol-linked sugar, mannosyl retinyl phosphate (MRP). Upon injection of [3H]retinol and [14C]mannose into rats, [14C, 3H]MRP could be isolated from liver and intestinal mucosa, and identified by chromatographic and hydrolytic experiments. The enzyme system that forms MRP from GDP-mannose and retinyl phosphate was located primarily in rough endoplasmic reticulum of fractionated liver cells, with some activity also in smooth membranes and Golgi apparatus. Vitamin A deficiency resulted in depressed synthesis of the rat serum glycoprotein alpha 1-macroglubin (alpha 1-MG), as shown by a decline in labeling. Analysis of the labeled alpha 1-MG from serum of normal and vitamin A-deficient rats showed this to be the result of a defect in glycosylation. The specific activity ratio (deficient:normal) of the alpha 1-MG of serum declined progressively with development of the deficiency, as a result of underglycosylation. Complete carbohydrate analysis of the alpha 1-MG of normal and deficient serum revealed a sugar loss in this glycoprotein as a result of vitamin A deficiency.

Animals↗
PubMed1977

Familial leukemia and inherited chromosomal aberration.

This communication contributes a family with 12 cases of cancer and two cases of leukemia. Chromosomal analysis was performed on three occasions, 9 months apart. In unaffected first-degree relatives, we have demonstrated high frequency of tetraradial figures: in parents, 1:243 mitoses, and in all first degree relatives, 1:328 mitoses. The rate of chromosomal breakage was moderately elevated in comparison with carefully matched controls, mainly in father (6.17), mother (4.01) and one sister (4.07). G-banded and C-banded karyotypes revealed no structural chromosomal abnormality in relatives of leukemic children. This family is one of five leukemic families investigated. Analogous methods of chromosomal analysis have been employed in all, but chromatid exchange figures and elevated chromosomal breakage were detected only in the presently reported pedigree. It has been postulated that in this family there exists a possible relation between increased incidence of chromatid exchange figures and increased tendency to leukemia.

Adolescent↗