McGill University Thèses et mémoires publiés en 1973

"Eight years of data on the effect of weather on the activity of Sorex cinereus .vere studied. Total activity was divided into yearly, period and daily components, studied separately. Possible effects of competition and predation on each component were examined. Mathematical models of the effects of weather in each component were made, tested and found to be valid. Yearly variations in the shrew population are highly dependent on April temperature and rainfall and on spring population size. Over approximately two week periods during the year, activity and population size are slightly affected by temperature and moon phase. Daily activity rate …  Read more

Static and dynamic tension variations due to different after populations in the inferior oblique eye muscle of anesthetized cats were studied during changes in length and electrical activation, and following injections of succinylcholine. Mechanical stiffness vectors for these fiber populations, obtained from their responses to small sinusoidal length change, indicated at low frequencies the presence of velocity independent friction and, at high frequencies, a phase lag or tension relative to length in the active components. Isometric tension dynamics of single motor units were found to be variable. Studies on the whole muscle confirmed non-uniform dynamics and provided new information on …  Read more

Negativism was studied in nine autistic, nine behavior disturbed, and nine normal children aged five to 12 years in three different stimulus conditions (verbal requests for verbal responses, verbal requests for nonverbal responses, and nonverbal requests for nonverbal responses). Each condition included two tasks which were requested 15 consecutive times. Subjects demonstrated they could perform the tasks before testing, and their responses were scored according to the similarity between the response and the request. Results demonstrated the autistic and behavior-disturbed subjects responded similarly except when requests required verbal responses, in which case the autistic group was much more negative. The …  Read more

The rate of linoleate esterification by rabbit reticulocytes was twice that of normocytes, based on cellular lipid levels. Incorporation of glucose and glycerol carbons into lipids was minimal, indicating limited de nova synthesis. Esterification occurred primarily in the plasma membranes, with a small but consistent incorporation into the mitochondria and none into the microsomes. Thus, the intracellular membranes could not explain the increased reticulocyte esterification. Esterification was independent of ATP levels and not affected by exogenous lysolecithin. ATP in human normocytes was elevated to twice the initial level by a 5 hr incubation with glucose, adenine and pyruvate or inosine …  Read more

Dextran is a polymer of glucose known to possess several properties which may be desirable in extracorporeal circuits such as oxygenators and standard hemodialysis machines. However, the feasibility of using dextran to decrease platelet retention in the extracorporeal micro capsule shunt system has not been previously examined, and this is the subject of this thesis. In vitro, experiments demonstrated that dextran 70 was effective in decreasing platelet retention after 100 minutes exposure of blood to collodion microcapsules. In vivo studies, in which dogs were hemoperfused with extracorporeal shunts containing CAC microcapsules, showed that dextran 70, infused 1 - 2 hours …  Read more

The organic matrix of dentin contains collagen and a phosphoprotein, as well as small amounts of glycoprotein. Their elaboration by odontoblasts was investigated by radioautography using proline-3H to trace collagen, serine-3H and phosphate-33P to trace phosphoprotein, and fucose-3H to trace glycoprotein. Collagen polypeptides are synthesized in the rER, and pass to the Golgi apparatus where they are packaged into secretory granules in the form of procollagen, recognizable as filament aggregates. The granules migrate into the odontoblast process and release procollagen to the cell surface where collagen fibrils accumulate in large numbers within predentin. Phosphoprotein precursors also pass through the Golgi …  Read more

Five rhinovirus serotypes (types 3, 5, 14, 17, and 35) were studied using five serological techniques. The viruses were, grown in HeLa cell tissue cultures both in the presence and absence of a final concentration of 30mM magnesium chloride and antisera were produced in rabbit to each of the viral antigens. In the neutralizations test these viruses and their antisera gave only specific neutralization between each virus and its homologous antiserum.  Read more

Three phase recollection micropuncture studies were performed to assess the response of the remnant kidney in various stages of renal failure to furosemide administration (10 mg/kg) and graded volume expansion (3% and 10% body weight). Mean fractional excretion of sodium, potassium and water rose progressively in the normal dogs (Stage I) after the diuretic maneuvers, with a greater increase in the remnant kidneys in the presence (Stage II) and absence (Stage III) of the contralateral kidney. Proximal and distal TF/P inulin ratios were depressed after 3% volume expansion. However, proximal TF/P inulin was not further lowered after 10% volume expansion …  Read more

It is known that CNS mechanisms for inhibition of sympathetic activity exist, but the underlying circuitry and cellular mechanisms are largely unknown. As an attempt to clarify these points, the inhibitory effect, on single antidromically identified sympathetic preganglionic neurons, of electrical stimulation of high threshold somatic and visceral afferents, descending fibres in the lateral funiculus of the spinal cord and depressor area of the medulla oblongata, near the obex, have been examined. With extracellular recording, inhibition was seen as a depression of spontaneous or glutamate-evoked firing and of antidromic soma invasion, unrelated to a previous excitation. All the inputs studied …  Read more

MacPherson, Hugh (Supervisor)  Read more

Une protéine (SCP) de grand pouvoir immunogène a été extraite, avec NaCl 0.lM, de la moelle épinière de boeuf, protéine qui a été localisée uniquement dans le tissu nerveux. L'analyse immuno-électrophorétique démontra trois formes moléculaires de SCP, dont deux furent retenues à l'intérieur du sac à dialyse. Ces deux formes ont démontré des mobilités électrophorétiques d'une beta1-globuline (beta1-SCP) et d'une gamma-globuline (gamma-SCP) tandis que la forme dialysable la mobilite d'une gamma-globuline. Beta1-SCP a été isolé par absorption en volume des extraits de la moelle épinière de boeuf avec DEAE-Sephadex A-50, suivie par chromatographie sur cellulose CM-52, gamma-SCP a été isolé …  Read more

Vagal and mechanical aspects or ventilatory control have been studied. The behavior or vagal inspiratory inhibitory influence following lung inflations was assessed by determining the excitatory influence required to terminate apnea. It was found that, following inflation, vagal inhibitory influence declines rapidly and then attains a plateau which varies with lung volume. The duration of apnea was found to be critically affected by the course of chemical events following inflation and is therefore, unsuitable for quantitating the vagal inhibitory influence. An alternate method is described based on comparison of the unloaded tidal volume with the inspiratory pressure wave generated following …  Read more

Agars from five major groups of agarophytes (Rhodophyceae) have been fractionated on DEAE Sephadex A-50 (Cl-). The results indicate that agar is a complex mixture of polysaccharides all having the same backbone structure but masked to a variable degree with charged groups, ranging from the essentially neutral agarose to highly sulfated galactans. The agarases which degrade agarose have been isolated from marine and soil bacteria. The mode of action of these agarases and the end products of the hydrolysis have been investigated. Purified bacterial agarases con be classified into two major groups, being specific for either the beta linkages, P. …  Read more