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Biomedical subjects

W L Ryan

Publications and source records attributed to W L Ryan.

At least 19 recordsLinked to original sources
PubMed1990

A new platelet function test.

A method for screening EDTA(K3) blood samples for platelet function is described. The general availability of whole blood platelet counters in the clinical laboratory suggested their use to measure platelet aggregation. To simplify the collection and storage of blood samples, a method utilizing EDTA collected blood is described. Addition of calcium and citrate restores platelet function to blood samples even when stored at room temperature for several hours. Thus, the blood sample used to assay RBC, WBC and platelet parameters may also be employed in platelet aggregation. A comparison of this method with aggregometry on 120 subjects indicated a similar response to arachidonate, collagen, ristocetin and ADP.

Adenosine Diphosphate↗
PubMed1984

Chemical induction of ovarian epithelial carcinoma in mice.

Murine ovaries were treated with silk sutures saturated with a solution of 7,12-dimethylbenz(a)anthracene in beeswax. One of 35 animals developed an epithelial carcinoma. This tumor was not successfully transplanted into young animals.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1982

Sperm-agglutinating and -immobilizing antibody formation following vasectomy prevented with dexamethasone in cynomolgus monkeys.

Cynomolgus monkeys (Macaca fascicularis) were treated with 1.5 mg/kg dexamethasone (DEX) before (4 to 2 days) and after (0, 2, 4, and 7 days) vasectomy. Of the four monkeys treated with DEX, only one developed sperm antibody as measured by sperm-agglutinating and sperm-immobilizing assays. All six of the vasectomized monkeys not given DEX developed both agglutinating and immobilizing sperm antibodies. In this study, DEX given before and after vasectomy blocked sperm-agglutinating and -immobilizing antibody formation. We conclude that the major antigenic exposure to sperm responsible for sperm-agglutinating and -immobilizing antibody comes at the time of vasectomy.

Animals↗
PubMed1981

Prevention of autoimmunization to spermatozoa by passive antibody.

The objective of this investigation was to determine if sperm antibody formation after vasectomy in guinea pigs can be inhibited by passive administration of antiserum to spermatozoa. Sperm antibody was obtained by bleeding vasectomized guinea pigs which had sperm-agglutinating antibody titers of 1 : 16 or higher. Gamma globulin was obtained by ammonium sulfate precipitation. Vasectomized guinea pigs were injected with immune gamma globulin and normal gamma globulin for a period of two weeks after vasectomy. In the group receiving normal gamma globulin the serum titer of sperm-agglutinating antibody reached 1 : 32 and remained at that level for duration of the study. In guinea pigs receiving immune gamma globulin detectable serum titers of sperm-agglutinating antibody did not develop. The investigation suggests that sperm antibody formation can be prevented by treating vasectomized animals with passive sperm antibody to spermatozoa.

Animals↗
PubMed1980

Platelet adsorption-source of error in reference controls.

Preparation of platelet reference controls requires that the platelet membranes be strengthened by chemical cross-linking, usually with glutaraldehyde. The reaction produces a platelet which is strongly absorbed to plastic and glass surfaces. Tests of commercially available reference controls indicate adsorption to the counting containers. Surfactants inhibit adsorption but cause an apparent decrease in size. Polyethylene glyocol can eliminate adsorption without altering conductivity.

Aldehydes↗
PubMed1979

Initiation-promotion skin carcinogenesis: inhibition by cyclic and non-cyclic nucleotides.

The effect of nucleotides on initiation-promotion skin carcinogenesis in Swiss mice was investigated. Cyclic AMP was given before initiation with DMBA, between initiation and promotion, and at the same time as promotion with croton oil. Cyclic AMP was more effective in inhibiting tumor development when injected at the same as promotion with croton oil. 5'-adenosine-monophosphate (5'-AMP) and cyclic GMP were as effective as cyclic AMP in inhibiting tumor development under these conditions. However, adenosine, dibutyryl-cyclic AMP and 5'-guanosine-monophosphate (5'-GMP) were ineffective.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

Antibody stimulation of benzo(a)pyrene carcinogenesis.

Benzo(a)pyrene (BP) was conjugated to horse serum albumin (HSA) and then attached to aldehyde fixed human erythrocytes. These cells were used in a passive hemagglutination test to measure BP antibody. BP antibodies were found to be induced in Swiss mice injected with tumorigenic doses of BP. Of the mice treated with BP, those which developed tumors soonest had the highest levels of BP antibody. This observation suggested that the antibody to BP may stimulate tumor development. When rabbit antibody to BP was injected with BP a significantly increased tumor formation occurred. Active immunization using BP conjugated to a foreign protein also significantly increased tumor formation when the mice were treated with BP. Our findings suggest that the immune response to carcinogens is an important component of the carcinogenic process.

Animals↗
PubMed1978

Stimulation of malignant skin cells by antibody to normal skin cells of mice.

The ability of antibodies developed against normal skin cells to stimulate skin cells transformed by 7,12-dimethylbenz[a]anthracene (DMBA) was investigated. Primary cultures of normal skin, containing both fibroblasts and epithelial cells, were established from epidermis of the back skin of adult strain A/J mice. Malignant skin cells were obtained by treating a subculture of normal cells with DMBA. Transformation was demonstrated by increased growth rate, growth in soft agar, and production of tumors in strain A/J mice. Antisera developed in New Zealand White rabbits against the normal cells were cytotoxic to both normal and malignant cells in the presence of complement of 1:320 dilution. However, greater dilutions of the antisera (1:500-1:1,000) in the absence of complement produced growth enhancement of the malignant but not of the normal cells. The growth-enhancing properties were present in the gamma-globulin fraction of the antisera that contained IgG, IgM, and IgA antibodies. Immunofluorescence studies indicated that antibodies from the sera bound to the membranes of both normal and malignant cells. These data indicate that antibodies to normal cells are stimulatory to DMBA-transformed cells and confirm previous data obtained with spontaneously transformed cells.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1975

Initiation-promotion skin carcinogenesis and immunological competence.

The immune competence of mice during initiation-promotion skin carcinogenesis was determined by skin allograft rejection and lymphocyte mitogenesis. The carcinogen 7, 12-dimethylbenzanthracene inhibited the cellular immune competence of mice while lymphocytes from croton oil treated mice had enhanced PWM response. Chlorphenesin, a stimulator of cellular immunity, was found to inhibit tumorigenesis in initiation-promotion skin carcinogenesis when injected during promotion.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1975

Adenylate cyclase stimulation by trypsin.

Adenylate cyclase activity of a rat embryo fibroblast cell line (F111) is markedly increased by brief treatment with 1:300 trypsin. The degree of stimulation depends upon the length of time the cells are treated and the concentration of trypsin. Crystalline trypsin produced a stimulation similar to that obtained with 1:300 trypsin. Further, the addition of soybean trypsin inhibitor blocked the stimulation of adenylate cyclase by 1:300 trypsin. Trypsin-treated adenylate cyclase responds to PGE1, but there is no increase over that of untreated enzyme. This result and the increase in fluoride-stimulated levels of activity suggest that the trypsin is acting upon the catalytic unit of the enzyme.

Adenylyl Cyclases↗