It has recently become increasingly obvious that the present means (endoscopy and urography) of evaluation of early or minimal cases of lower urinary tract obstruction may be totally inadequate. Endoscopic examination of the lower urinary tract may reveal trabeculation of the bladder, which could be secondary to outlet obstruction, but with no direct evidence of such obstruction. On the other hand, the bladder wall may appear normal in the presence of urethral obstruction. Similarly, urography does not provide the meansn of adequately evaluating such cases. [...]

It is well known that not only histamine but also other smooth muscle stimulating substances play a role in the symptomatology of different types of allergic diseases. The substance most widely studied in this field is histamine which is responsible for a number of symptoms of allergic diseases. In the past 50 years, a great deal of work has been carried out to find new drugs which either prevent release of histamine or its action on smooth muscles and vessels. [...]

In spite of recent therapeutic strides in the treatment of the shock syndrome, there is still a high mortality rate. In recent years there have been more and more proponents of the idea that vasoconstrictors are not the ideal agents for the treatment of this syndrome and that one may be falsely secure when reading normotensive pressures on the sphymomanometer as this may not reflect the hemodynamic state of the patient as a whole. A few have rounded the circle and advocated the use of adrenergic blocking agents. [...]

Recent projects in this laboratory have been devoted to the study of a number of problems related to acute experimental pancreatitis. The first of a series of findings in this field of endeavour was the demonstration that a uniformly fatal form of acute haemorrhagic pancreatitis could be induced in the dog. With this tool in hand, further experiments implicated the release of bradykinin in the pathogenesis of the clinical manifestations of the glandular insult. It was simultaneously shown that the proteinase inhibitor Trasylol (FBA Pharmaceuticals) could favourably alter the mortality rate of animals inflicted with this disease and appreciably decrease the amount of active bradykinin released in the course of experiments. [...]

The complete cycle of albumin metabolism is now known in its broadest outline. The site of albumin synthesis had long been implicated to be in the liver by clinical observations and more recent studies on isolated perfused rat liver with radioactive labelled amino acid have confirmed these impressions, but the mechanism of its breakdown remained to be elucidated until 1959 Birke et al. and 1960 Wetterfors et al. demonstrated that a large percentage of breakdown occurred in the stomach and small intestine. In 1961, Katz et al. demonstrated the rate of catabolism of albumin in rats to be about 20% in the gastrointestinal tract, 25% in the liver and 50% in the muscle and skin. [...]

The function of a valve is to alter or regulate a flow or movement, and/or render it unidirectional. The body's valve mechanisms would constitute a fascinating study in themselves if for no other reason than for the variety of which Mother Nature has availed herself. Some are thought of commonly in terms of 2-way flow (laryngeal cords, lips, nasal turbinates) while most are thought of as being associated with 1-way flow (iris, external nares, cricopharyngeal or upper esophageal sphincter, all the heart valves, venous valves, pylorus, sphincter of Oddi, ileo-caecal valve, urethral sphincters). Some are active (anal sphincters) and some passive (valve of the coronary sinus). [...]

Missing pages / It has been known for many centuries that the lymph nodes and spleen become enlarged during the course of certain diseases. References to buboes and swelling of the spleen can be found in the writings of Hippocrates (91). With the development of techniques which allowed the microscopic anatomy of lymphoid organs to be studied, the concept arose that the lymph nodes could act as filters to prevent toxic substances from entering the blood circulation (21,183). Quantitative measurements showed that lymph nodes were very efficient at filtering out baeteria injected into the afferent lymphatic vessels(56). [...]

The work described in this thesis was undertaken due to scepticism of the basically accepted belief that "physiological" ileus occurred regularly after abdominal surgery. The aim, if the scepticism was justified, was to examine postoperative management from this point of view and to present a concept from which individual surgeons might further postoperative management to the benefit and comfort of their patients. The postoperative management of a patient who has undergone abdominal surgery is to a large extent, governed by the findings of abdominal auscultation. [...]

Early workers in the field of pituitary cytology classified the cells of the anterior pituitary according to their staining abilities. Thus Wolfe and Cleveland, in 1933, using Orange G and aniline blue, divided the cell types in the anterior pituitary of the female rat into three groups [...]

Our perceptual experience of the visual world relies on successful segmentation of distinct regions in an image to delineate the boundaries between them. This thesis details a series of studies that begin to bridge the gap between standard energy models of texture segmentation and the properties of natural textures that affect human texture segmentation in ecological settings. Psychophysical and computational methods are applied to a combination of natural and naturalistic textures in an effort to identify the statistics found in natural textures that are relevant to human texture segmentation mechanisms, and to understand how they are processed by the visual system. These studies draw a distinction between the energy present in an image of a texture (lower-order statistics, in the Fourier amplitude spectrum), and the spatial distribution of that energy (higher-order statistics, in the Fourier phase spectrum). The contribution of higher-order statistics to segmentation is assessed in a number of contexts by comparing psychophysical and model performance in the presence and absence of higher-order statistical information. As a whole, this work documents both the statistics that influence segmentation performance when they are the same on either side of the boundary, and those that enable performance when they define the boundary, while evaluating the extent to which present models of segmentation can take these statistics into account. The first study suggests that the higher-order statistics present in natural texture photographs not only influence but impair contrast-boundary segmentation mechanisms, and that sparseness may be a relevant higher-order statistic in this task. The second study uses naturalistic synthetic textures to assess individual image statistics experimentally. These experiments demonstrate that texture sparseness and global phase structure impair orientation and contrast boundary segmentation, but that local phase structure has little impact on segmentation. These findings can be accommodated by a standard filter-rectify-filter model in which the shape of the intermediate-stage nonlinearity is compressive. The third study suggests that global phase structure and texture sparseness can both enable and influence segmentation in the absence of any lower-order statistical cues for segmentation. The same model employed for contrast and orientation boundary segmentation data in the previous experiments can also account for the role of global structure and density, but not the role of local phase alignment, in these kinds of texture boundaries. / Notre expérience perceptuelle du monde visuel se base sur la bonne segmentation de régions distinctes dans une image pour en délimiter les bords. Cette thèse présente une série d'études qui tendent à combler le fossé entre les modèles d'énergie standards de segmentation de texture et les propriétés des textures naturelles qui affectent la segmentation de textures par l'homme en conditions écologiques. Des méthodes psychophysiques et computationnelles sont appliquées à une combinaison de textures naturelles et naturalistes afin d'identifier parmi les statistiques des textures naturelles, celles qui sont utiles aux mécanismes de segmentation de textures et comment elles sont traitées par le système visuel de l'homme. Ces études distinguent l'énergie présente dans l'image d'une texture (statistiques d'ordre plus bas dans le spectre d'amplitude de Fourier), et la distribution spatiale de cette énergie (statistiques d'ordre plus haut dans le spectre de phase de Fourier). La contribution des statistiques d'ordre plus haut à la segmentation est étudiée dans différents contextes en comparant les performances psychophysiques à celles de modèles, en présence ou non d'information statistique d'ordre plus haut. Dans l'ensemble, ce travail présente à la fois les statistiques qui influencent la performance de segmentation lorsqu'elles sont les mêmes de chaque côté d'un contour et celles qui la permettent lorsqu'elles définissent le contour, en évaluant jusqu'à quel point les modèles de segmentation présentés peuvent prendre en compte ces statistiques.La première étude suggère que les statistiques d'ordre plus haut présentes dans les photographies de textures naturelles non seulement influencent mais altèrent les mécanismes de segmentation de contours de contraste, et que la dispersion peut être une statistique d'ordre plus haut pertinente pour cette tâche. La seconde étude utilise des textures synthétiques naturalistes pour évaluer expérimentalement les statistiques de chaque image. Ces études démontrent que la dispersion des textures et la structure de phase globale altèrent la segmentation de contours définis par le contraste ou l'orientation mais que la structure de phase locale n'a que peu d'impact sur la segmentation. Ces observations peuvent être accommodées par un modèle standard filtre-redresse-filtre dans lequel la non-linéarité du niveau intermédiaire est compressive. La troisième étude suggère que la structure de phase globale et la dispersion peuvent toutes deux permettre et influencer la segmentation en l'absence d'indice statistique d'ordre plus bas. Le même modèle employé pour la segmentation de contours définis par le contraste ou l'orientation peut aussi expliquer le rôle de la structure et de la densité globale mais pas le rôle de l'alignement local de phase dans ce type de contours de texture.