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Biomedical subjects

H Gershon

Publications and source records attributed to H Gershon.

98 records · Page 6Linked to original sources
PubMedDate not supplied

The lack of altered enzyme molecules in "senescent" mouse embryo fibroblasts in culture.

In order to compare the biochemical events occurring in senescent animals in vivo with those of fibroblasts demonstrating a limited life span in tissue culture, experiments were performed to determine whether altered enzyme molecules are produced in late passage mouse embryo fibroblasts in tissue culture. Such altered enzymes have been previously described by us in both senescent mice and nematodes. Fibroblast cultures, initiated from BALB/c embryos underwent approximately 7 population doublings before reaching stationary phase. A comparison was made of the enzyme activity and the quantity of antigen of the enzyme aldolase present in these cultures. The amound of aldolase per cell as well as the amount of enzyme per unit of antigen remained constant throughout the in vitro lifespan of these cells. Further evidence testifying to a lack of enzyme alteration in vitro was obtained in experiments testing temperature sensitivity. The aldolase from all passages was equally sensitive to heating at 60 degrees C.

Aging↗
PubMedDate not supplied

The affinity and spectrum of cross reactivity of antibody production in senescent mice: the IgM response.

Experiments were performed to determine whether the IgM component of the primary humoral immune response of senescent mice differs from that of young-adult mice in its affinity, specificity or heterogeneity. For this purpose, mice were immunized with the T-dependent antigen, TNP-KLH, or the T-independent antigen, TNP-LPS. Affinity and specificity of the anti-TNP response were studied at the cellular level by the plaque inhibition technique using the cross-reacting haptens TNP-epsilon-aminocaproic acid )TNP-EACA),DNP-EACA and ONP-EACA. It was found that when the immunogen was TNP-KLH, the peak IgM response was delayed in senescent animals by several days as compared to the response in young adults. However, the number of PFC on the day of peak response was comparable. No age related delay in the peak of response was detected when the antigen was TNP-LPS although the magnitude of response was reduced in old age. The average affinity of the plaque forming cell responses to both immunogens is comparable in young and old mice.

Aging↗
PubMedDate not supplied

The anti-inflammatory role of the erythrocyte: impairment in the elderly.

Human erythrocytes have significant anti-inflammatory capability. Via their complement receptor, CR1 (CD35), they function as the major carriers of immune complexes in the circulation and as a co-factor for factor-I in the cleavage of C3b and the resultant inactivation of C3- and C5-convertases. Erythrocytes of the elderly are defective in their control of C3- and C5-convertases and are thus defective in protecting the elderly from the inflammatory consequences of the activation of complement in the circulation. This defect stems from the reduced levels of CR1 and decay accelerating factor and from defective CR1 function. Erythrocytes of the elderly resemble senescent erythrocytes from young donors in that their CR1 can neither bind immune complexes nor function as a co-factor in the factor-I mediated cleavage of C3b. The erythrocytes of the elderly are defective in both promoting convertase decay and supporting C3b cleavage. The reduced levels and functional defects of erythrocyte CR1 should hamper the ability of the elderly individual to effectively clear the circulation of potentially inflammatory immune complexes as well as of micro-organisms which have bound complement via the alternative complement pathway. This defect in the ability to clear immune complexes and micro-organisms bearing C3b from the circulation should render the elderly individual susceptible to varied pathologies including infection, inflammation and concomitant damage to the vascular tissue commonly observed in the elderly.

Journal Article↗
PubMedDate not supplied

Detection of antisperm antibodies: a cytotoxicity immobilization test.

The sera of 110 couples with unexplained infertility were examined for anti-sperm immobilizing antibodies with the aid of multiple-exposure photography. The sera of 10 females and 3 males had immobilizing activity. Eleven pregnancies occurred in 10 female patients in the group without immobilizing antibodies. None of the 13 females in the couples with immobilizing activity conceived. A negative correlation was found between the occurrence of serum immobilizing antibodies and incidence of pregnancy. No such correlation could be found between the occurrence of autoagglutination in the male's ejaculate and the female partner conceiving. In light of detection of anti-sperm antibodies in a patient with habitual abortions, a possible immune mechanism is suggested.

Adult↗