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Biomedical subjects

F J DIXON

Publications and source records attributed to F J DIXON.

At least 37 records · Page 2Linked to original sources
PubMed1961

Experimental glomerulonephritis. The pathogenesis of a laboratory model resembling the spectrum of human glomerulonephritis.

Daily injections of any one of several foreign serum proteins produced in rabbits functional and morphological alterations similar to those seen in acute, subacute, and chronic human glomerulonephritis. The critical factor determining whether a rabbit would develop renal disease and the type of disease developed was the amount of antibody the rabbit formed. Those responding with much antibody were likely to develop an acute, self-limited glomerulonephritis and to be subsequently immune to further renal damage. Those responding with antibody barely sufficient to neutralize the antigen injected developed subacute and chronic glomerulonephritis. In the circulation of the rabbits with chronic glomerulonephritis, there was a daily recurring antigen-antibody reaction in the region of near antigen excess to near antibody excess which presumably led to the disease. Antigen apparently in the form of antigen-antibody complexes was deposited along the renal capillary basement membranes coincident with the development of subacute and chronic glomerulonephritis. Once developed, the morphologic stigmata of chronic glomerulonephritis persisted even after injections of antigen were stopped. However, in milder instances the renal function recovered in part after stopping antigen. This experimental model has several implications: first, the renal injury is precipitated by antigens with no known affinity for, or immunologic relationship to, kidney; second, antigen antibody complexes localize in the kidney, apparently on the basis of non-immunologic factors, and may be an etiologic agent of renal injury; third, severe hypersensitivity disorders can be related specifically to relatively poor as well as to good antibody responses; and finally, the pathogenesis suggested here offers an alternative to that of nephrotoxic serum nephritis for the experimental approach to the study of human glomerulonephritis.

Animals↗
PubMed1960

The metabolism of serum proteins in neonatal rabbits.

1. Incorporation of S(35)-labeled amino acids into serum proteins has been studied in neonatal and developing rabbits. It was found that, per unit weight, neonatal rabbits synthesized only about 1/36 of the gamma globulin, 1/7 of the beta globulin, (1/2) of the alpha globulin, and (1/8) of the albumin that an adult synthesized. The growing rabbit developed the ability to synthesize various serum proteins at different times. 2. Plasma volumes and serum protein concentrations were determined at different times during the growth period of the rabbit. Plasma volumes were found to be 1 and (1/2) times larger in newborn animals than in adults, with a gradual decline to the adult level. The total serum protein concentration at birth was about 60 to 65 per cent of the adult value and gradually increased with growth as the plasma volume decreased. 3. Half-lives of homologous albumin and gamma globulin were studied. The half-life of albumin in neonates was nearly twice as long as the half-life in adults, the latter value being reached at 1 month of age. The half-life of gamma globulin in neonates was more than twice as long as the half-life in adults and reached adult values at 2 to 3 months. 4. Attempts were made to alter serum protein metabolism. Gamma globulin synthesis early in life was augmented with antigen injections.

Animals↗
PubMed1959

The role of polymorphonuclear leukocytes in the initiation and cessation of the Arthus vasculitis.

The role of polymorphs in the Arthus type hypersensitivity vasculitis has been studied. Polymorphs were found to play an essential role in not only producing the inflammatory vasculitis, but also were instrumental in ridding the damaged vessel of the antigen, probably by means of proteolytic catabolism at the inflammatory site. A temporal relationship between the disappearance of antigen from the damaged vessels and a decrease in inflammatory reaction was found. The earliest localization of antigen and its associated rabbit globulin in the Arthus vasculitis was found to be beneath the endothelium of small vessels. Since submitting this article for publication, Sorkin and Boyden (J. Immunol., 1959, 82, 332) have reported the catabolism of antigen in the presence of antibody by mononuclear cells obtained from the peritoneal cavities of guinea pigs. Evidence was presented indicating that the antigen molecule was actually broken down by the mononuclear cells. Techniques similar to those reported here were used.

Animals↗
PubMed1959

Nature of colchicine resistance in golden hamster.

The unresponsiveness of the golden hamster to colchicine has been shown to be the result of a resistance of individual cells to the drug. This resistance makes it possible to use hamsters with heterotransplanted tumors for testing the in vivo effects of colchicine on the tumors, with no toxic host reactions.

Animals↗
PubMed1959

The nature of the immunologic inadequacy of neonatal rabbits. II. Antibody formation by neonatal splenic cells transferred to adult recipients.

It has been shown that cells from neonatal rabbits are capable of producing considerable amounts of antibody after exposure to antigen in vitro and transfer to x-radiated adult recipients. This suggests that the immunological inadequacy of these neonates is not dependent primarily upon the lack of cells capable of antibody formation. Both in vitro sensitized neonatal lymphoid cells and in vivo sensitized adult lymphoid cells made much more antibody after transfer to x-rayed adult recipients than to neonatal recipients. Possible reasons for and significance of these observations are pointed out in the discussion.

Animals↗