McGill University Thèses et mémoires publiés en 1971

Steinberg, Blema (Supervisor)  Lire la suite

The passive administration of antibody before, simultaneously with, or shortly after antigen can result in a markedly suppressed or sometimes enhanced immune response. The effect of prior administration of two classes of 7S mouse anti-sheep red blood cell (SRBC) immunoglobulins on the primary immune response to SRBC was studied. Mouse gammaGl and gammaG2 immunoglobulins were isolated from serum by a combination of Pevikon-Geon zone electrophoresis followed by density gradient isoelectric focusing. The immunoglobulins were defined by qualitative and quantitative studies, and their effects on the primary response were determined by administering doses ranging from 0.5 mg to 0.001 mg of …  Lire la suite

Antibodies, against PGH, PLR and HGH were detected by radioimmunological methods in patients on HGH therapy. The presence of antibodies detectable by 125I PGH was further confirmed by Immunofluorescent method. These antibodies were localized in IgG fraction of serum immunoglobulins. Such antibodies did not neutralize the effect of HGH in the tibia test. Aggregation of HGH and revealed determinants were considered to be responsible for production of such antibodies. Certain commercially available preparations of pitressin were noted to have several contaminating proteins. Antibodies induced by such proteins (eg, PGH, PP) were noted in patients on pitressin therapy and such antibodies …  Lire la suite

Orvig, S. (Supervisor)  Lire la suite

The vasopressin level was measured by the antidiuretic assay after an extraction procedure based on adsorption of the hormone on an ion exchange resin. Modifications and problems related to these procedures have been discussed. The method was applied for: (a) Measurement of plasma ADH in dogs with surgically induced congestive heart failure and in patients with congestive heart failure. There was no definite correlation between the level of plasma vasopressin and the occurrence of cardiac edema. (b) Studying the effect of chlorpropamide administration on the level of urinary ADH in a patient with diabetes insipidus in order to have some …  Lire la suite

The effect of thermal stimulation of the skin and the pre­optic region of the brain on posterior hypothalamic neurons was studied in anesthetized and unanesthetized cats. Both sites of stimulation are known to have thermosensory functions in temperature regulation: the recording site has known thermogenic and heat conservation functions. Units responsive to one or both sites of stimulation were found. The majority increased their activity with decreasing temperature. The number of units which responded to stimulation at both sites was greater than that expected by chance from the number which responded to only one site or the other; and the …  Lire la suite

The mixed leucocyte reaction and the delayed hypersensitivity antigens histoplasmin and tuberculin purified protein derivative were used in combinations to test the clonal selection theory in vitro. When histoplasmin was added to mixed leucocyte cultures containing sensitized cells from one donor, there was always an additive blastogenic effect. Experiments using different proportions of histoplasmin positive and negative cells in mixed cultures indicated that the response to histoplasmin was a specific one, and depended on the number of sensitized cells present in the cultures. Preincubating positive or negative donor cells with histoplasmin prior to setting up mixed cultures led to the …  Lire la suite

A method has been described by which the total population of regenerating cutaneous nerves can be studied, and has been sequentially applied to free skin grafts in the rabbit. It has been shown that both myelinated and unmyelinated fibers regain their normal caliber quite early. However, a regenerating fiber population imbalance was found throughout the study. This was demonstrated by an increased number of nerve bundles, an increase in the number of unmyelinated fibers, a decrease in the number of myelinated fibers, and an absence of end corpuscles in the grafts. It is concluded that nerves enter the graft very …  Lire la suite

The actions of certain hormones and drugs on the release of materials endogenous to rat brain synaptosomes, liver mitochondria, peritoneal mast cells and red cells were studied. In general, it was found that the tranquillizers, chlorpromazine and reserpine (10^-7 - 10^-5M), inhibited the release of acetylcholine from synaptosomes, protein from mitochondria, histamine from mast cells and haemoglobin from red cells. Analgesics such as aspirin, acetanilide and morphine (10^-4 - 10^-2M) and the adrenergic blocking agent bretylium toaylate (l0^-7 - l0^-5M) exhibited both potentiation and inhibition of release of the markers from the four particles, depending on the concentrations used. On …  Lire la suite

One carbon transfer from N5,l0-methylenetetrahydrofolate to deoxyuridylate to form thymidylate leads to dihydrofolate formation, and depends upon dihydrofolate reductase to regenerate the active coenzyme. Methotrexate inhibits dihydrofolate reductase and consequently blocks one carbon fragment metabolism. In Ehrlich ascites cells methotrexate depresses the rate of formate-14C labelling of purine nucleotides, RNA and serine. Deoxyuridine and deoxycytidine, both of which can give rise to thymidylate and therefore lead to dihydrofolate formation, cause an increased inhibition of formate-14C metabolism by methotrexate. Addition of 5-fluorodeoxyuridine, which is phosphorylated to 5-fluorodeoxyuridine monophosphate an inhibitor of thymidylate synthetase, or addition of thymidine, reverse the inhibitory action …  Lire la suite

1. Methionine exchange diffusion is insensitive to Na+, K+, their gradients and prior depletion of cellular ATP. 2. In the absence of extracellular Na+, methionine uptake can he divided into two components; an initial rapid exchange between methionine and several endogenous amino acids and a slower net uptake inhibitable by alpha-aminoisobutyric acid and L-alanine. 3. After depletion of endogenous ATP and amino acids, carrier mediated methionine uptake from Na+-free medium was barely detectable. This and the evidence in 2 above indicates that the exchange carrier cannot catalyze net methionine uptake. 4. Cellular ATP and extracellular Na+, rather than transmembrane Na+, …  Lire la suite

In autotransplanting the whole small intestine, one of the problems has been the difficulty of getting long term survivors consistently. Aside from the delicate mesenteric artery and vein anastomosis, the susceptibility of the organ to ischemia is quickly translated into irreversible mucosal damage. The objective of this project is to study a number of technical variations during small intestine autotransplantation and their effect on the intestinal mucosa during the operation and the immediate post-operative period. Over seventy small bowel autotransplantations were done on dogs and forty-four were included in the present study. Histologic and Biochemical studies were performed on tissue …  Lire la suite