Biomedical subjects
M C Hardegree
Publications and source records attributed to M C Hardegree.
Cholesterol-dependent tetanolysin damage to liposomes.
Tetanolysin caused membrane damage, resulting in release of trapped glucose from liposomes containing cholesterol. Maximum glucose release occurred from liposomes that contained 50 mol% cholesterol. At higher or lower levels of cholesterol, glucose release was reduced and glucose release did not occur at all below 40 mol% cholesterol. The apparent activity of tetanolysin was not influenced by temperature (24 degrees C compared to 32 degrees C) or by liposomal phospholipid fatty acyl chain length. We conclude that tetanolysin caused cholesterol-dependent lysin-mediated damage to liposomes, possibly by means of a pore consisting of a complex of toxin and cholesterol.
Effect of tetanus toxin on the accumulation of the permeant lipophilic cation tetraphenylphosphonium by guinea pig brain synaptosomes.
Accumulation of the permeant lipophilic cation [(3)H]tetraphenylphosphonium (TPP(+)) by synaptosome preparations from guinea pig brain cerebral cortex is inhibited 1:10 by medium containing 193 mM K(+) and by veratridine. A further 1:10 to 1:15 decrease in TPP(+) uptake occurs under nitrogen and in the presence of mitochondrial inhibitors such as oligomycin, whereas starvation and succinate supplementation have no effect. These data indicate that, in analogy to intact neurons, there is an electrical potential (DeltaPsi, interior negative) of -60 to -80 mV across the synaptosomal membrane that is due primarily to a K(+) diffusion gradient (K(+) (in)-->K(+) (out)). The data also indicate that mitochondria entrapped within the synaptosome but not free mitochondria make a large contribution to the TPP(+) concentration gradients observed. Conditions are defined in which tetanus toxin binds specifically and immediately to synaptosomes in media used to measure TPP(+) uptake. Under these conditions tetanus toxin induces dose-dependent changes in TPP(+) uptake that are blocked by antitoxin and not mimicked by biologically inactivated toxin preparations. The effect of tetanus toxin on TPP(+) uptake is not evident in the presence of 193 mM K(+) or veratridine but remains under conditions known to abolish the mitochondrial DeltaPsi. Moreover, tetanus toxin has no effect on TPP(+) uptake by isolated synaptosomal mitochondria. The results thus define an in vitro action of tetanus toxin on the synaptosomal membrane that can be correlated with biological potency in vivo and is consistent with the in vivo effects of tetanus toxin on neuronal transmission.
Tetanus toxin interactions with the thyroid: decreased toxin binding to membranes from a thyroid tumor with a thyrotropin receptor defect and in vivo stimulation of thyroid function.
Normal rat thyroid membranes adsorb neurotoxicity when incubated with purified tetanus toxin. Membranes from a rat thyroid tumor with a thyrotropin receptor defect adsorb very little neurotoxicity when similarly evaluated. This inability of the tumor membranes to adsorb neurotoxicity is correlated with a defect in their ability to bind both 125I-labeled tetanus toxin and [125I]iodothyrotropin. The effect of tetanus toxin on the release of radioiodine from the thyroids of appropriately prepared mice has been measured by adapting methods used for the bioassay of thyrotropin. One minimum lethal dose of tetanus toxin given sc caused a significant release of radioiodine into the blood of mice 48 h after injection. In mice subjected to the stress of prior bleedings or anesthesia, the release of radioiodine from the thyroid by tetanus toxin was accelerated, i.e., the increase in blood radioiodine could be measured 24 h after injection. These results again suggest that tetanus toxin may interact with thyrotropin receptors on thyroid plasma membranes. The "sympathetic overactivity syndrome" seen in some patients with tetanus and the syndrome characterized as "thyroid storm" in patients with Graves' disease are discussed as they may relate to these observations.
Tetanus toxin interactions with thyroid plasma membranes. Implications for structure and function of tetanus toxin receptors and potential pathophysiological significance.
Explore the source record for details and available documents.
Interaction between tetanolysin and Mycoplasma cell membrane.
1. A partially purified tetanolysin preparation lysed the sterol-requiring Mycoplasma capricolum cells but had no effect on M. capricolum cells adapted to grow with no or very little cholesterol. The sterol-non-requiring Acholeplasma laidlawii cells grown either in a cholesterol-rich or a cholesterol-poor medium were unaffected by the tetanolysin preparation. 2. The lysis of M. capricolum cells by the tetanolysin preparation was temperature dependent, inhibited by cholesterol, sublytic concentrations of lucensomycin, and Mg2+. The sensitivity to lysis was greatly affected by the age of the culture, being highest in cells from the early logarithmic phase of growth and declining sharply thereafter. 3. Isolated M. capricolum membranes were capable of binding large amounts of the tetanolysin activity (up to 30 hemolytic units per mug membrane protein), 20 times as much as membranes of the adapted strain. The binding of tetanolysin activity to membranes was almost the same at 4,22, or 37 degrees C, and was very little affected by the age of the culture. The binding capacity of the membranes was not affected by the removal of 60-70% of membrane proteins by pronase digestion but markedly decreased with the removal of membrane lipids. 4. Of the five polypeptide bands detected in electrophorograms of the partially purified tetanolysin preparation, two bands (mol. wt. 44 000 and 42 000) were found to bind to the cholesterol-containing mycoplasma membrane preparation. EPR spectrometry revealed that the freedom of motion of fatty acid spin labels in the tetanolysin-treated membranes was markedly higher than that in untreated membranes. 5. The concept that tetanolysin interacts specifically with membrane cholesterol resulting in the shielding of cholesterol from its interaction with membrane phospholipids is discussed.
Diphtheria and tetanus toxoids: results of assays for the presence of bovine antigens.
Explore the source record for details and available documents.
Effect of allergenic extracts of house dust and bacterial vaccine on respiratory infections of mice.
Explore the source record for details and available documents.
Characterization of mannide monooleate.
Explore the source record for details and available documents.
Characterization of adjuvant mineral oils.
Explore the source record for details and available documents.
Influence of mouse strain on the assayed potency (unitage) of tetanus toxoid.
The assayed potency of an adsorbed tetanus toxoid C(2), relative to the international standard for tetanus toxoid (adsorbed), varied significantly with the use of different strains of mice. The unitage was highest with NIH mice, and it was not significantly different from that with CFW mice. With CDF(1) and BALB/c mice, however, the assayed potency was significantly lower than with NIH mice. C3H mice failed to respond to the dose range of the toxoids employed with the other four strains. The significance of the influence of the mouse strain on the designation of a prescribed unit requirement for tetanus toxoid, adsorbed, relative to human efficacy is discussed.
Mineral oil adjuvants: biological and chemical studies.
Explore the source record for details and available documents.
Induction of interferon by bacterial vaccines and allergenic extracts.
Explore the source record for details and available documents.
Tetanolysin: in-vivo effects in animals.
Explore the source record for details and available documents.
A cell culture assay to evaluate the toxicity of arlacel A.
Explore the source record for details and available documents.
Immunization against neonatal tetanus in New Guinea.
THIS PAPER DESCRIBES: (1) a continuation of the study reported in 1965 of tetanus antitoxin titres among women after primary immunization with plain, AlPO(4)-adsorbed or oil adjuvant toxoids; (2) the effect of age and of abscess formation due to oil adjuvants on antitoxin response; and (3) a comparative study of titres in some women of the study groups who received either a plain or an AlPO(4) toxoid booster injection in pregnancy.The results support our previous recommendation to use aluminium adjuvant toxoid in the prevention of neonatal tetanus. Mean maternal protective antitoxin levels were maintained for 40 months but not for 54 months after 2 primary injections and booster response was higher in those immunized with this toxoid than in those immunized with plain toxoid. Also, the use of AlPO(4) toxoid as booster stimulated a higher antitoxin response than did the use of plain toxoid. Mean protective levels induced by oil adjuvant toxoids (1 injection) persisted for the same time as for the adsorbed toxoid (2 injections). Age did not significantly affect the level of antitoxin response, whereas abscess formation was associated with a higher level.Pregnancy appeared to favour the incidence of antitoxin responders to adsorbed toxoids. Failure to respond to primary immunization with 2 injections of adsorbed toxoid occurred in 7% of women while 100% responded to the oil adjuvant toxoids. Induction of abscess formation precludes use of the latter toxoids, however. Additional studies are needed on the influence of larger antigen doses on the primary response in different ethnic and ecological situations and on the influence of smaller antigen doses on the booster response where repeated booster injections are indicated.
Immunization against neonatal tetanus in New Guinea. 3. The toxin-neutralization test and the response of guinea-pigs to the toxoids as used in the immunization schedules in New Guinea.
The mouse toxin-neutralization test procedure described has been used for antitoxin titration of sera of New Guinea women following primary immunization with plain and adjuvant tetanus toxoids and following booster immunization, and for titration of guinea-pig sera.The responses of guinea-pigs immunized with the same toxoids and immunization schedule to simulate the human field trial studies were observed for 6 months. The relative antitoxin responses of guinea-pigs to the different toxoids were similar to those of the women.
Immunization against neonatal tetanus in New Guinea. 4. Comparison of tetanus antitoxin titres obtained by haemagglutination and toxin neutralization in mice.
Haemagglutination (HA) has been used frequently for the titration of tetanus antitoxin but published results have varied in relation to the "unitage" determined by the mouse toxin-neutralization test (TN). This report gives the results of the titration of a group of sera by haemagglutination and compares them with the results obtained by toxin neutralization. Although there was marked variation between HA and TN titres of individual sera, results indicated that haemagglutination is a useful procedure for the over-all evaluation of the antitoxin responses to tetanus toxoids in field studies.