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Biomedical subjects

M W Donner

Publications and source records attributed to M W Donner.

At least 37 records · Page 2Linked to original sources
PubMed1985

Adaptation, compensation, and decompensation of the pharyngeal swallow.

Under normal circumstances, the act of swallowing adjusts to varying demands of different bolus characteristics and different head and neck postures. When the swallowing mechanism is impaired by disease, adjustment is essential to compensate for the impairment and allow swallowing. Evidence of adjustment can be demonstrated by cineradiography which provides important clues to the presence of underlying disease. When adjustment to disease is inadequate, swallowing decompensates. In this case, gross changes in swallowing performance are evident from clinical evaluation and cineradiography.

Adaptation, Physiological↗
PubMed1985

The Swallowing Center: concepts and procedures.

This paper describes the purpose and organization of a dedicated center at The Johns Hopkins Medical Institutions for the evaluation of swallowing problems. The multidisciplinary approach outlined will permit a better understanding and more accurate diagnosis of the functional or organic lesions affecting the swallowing mechanisms. Illustrative cases are presented.

Adult↗
PubMed1985

Radiologic evaluation of swallowing.

Diagnostic imaging procedures are useful to analyze the complex mechanism of swallowing. They may be employed beneficially to answer specific questions of swallow coordination, and to distinguish between various forms of airway penetration. The pathophysiology of upper and lower airway involvement may be determined and visualized.

Carcinoma, Bronchogenic↗
PubMed1985

Anatomy and physiology of the pharynx.

Radiographic evaluation of the passage of a bolus from the mouth through the pharynx into the esophagus is based upon identification of specific anatomical landmarks and the integrated motion accomplished by the oral and pharyngeal muscles during swallowing. Twenty-six muscles and 6 cranial nerves must be coordinated to enable the safe performance of the complex physiological task of transporting liquids and firm food from the mouth into the esophagus. The following discussion and illustrations of pharyngeal anatomy and physiology are pertinent to an understanding of normal swallowing function.

Deglutition↗
PubMed1979

In vitro computed tomography of the human placenta.

A plastic holding device has been devised to allow in vitro computed tomography of term human placentas. Graded dilutions of iodinated contrast medium have been injected into the fetal placental circulation and into the intervillous space of placental lobules perfused with normal saline solution. Computed tomography in different orientations has imaged Borell's "jets" on the maternal side and cotyledonary vascular "puffs" on the fetal side of the placenta. Attenuation coefficients, before and after injection of contrast medium may be used for quantitative investigation of the physiological placental circulation and possibly for diagnosing placental pathology.

Humans↗
PubMed1976

Normal and abnormal motility of the stomach.

The analysis of gastric motility makes possible the distinction between purely anatomic changes and those of a functional nature with or without associated morphologic alterations. Hence, through evaluation of gastric and duodenal motor function contributes significantly to the radiographic examination of the upper gastrointestinal tract.

Aged↗
PubMed1975

Radionuclide and angiographic studies of placental circulation in man and rhesus monkey.

Imaging maternal and fetal circulation during perfusion of isolated human placental lobules was performed. Radionuclide and contrast angiograms, specimen scans, and histologic preparations obtained on human material during in vitro investigations were compared to the results obtained in vivo on pregnant rhesus monkeys. The distribution of maternal blood flow within the placenta appeared similar in both human and rhesus studies. The 'spurts' of radiopaque medium shown on the contrast angiograms correlated with the appearance of areas of increased radioactivity. These 'hot spots' are located where the uteroplacental spiral arteries open into the intervillous space or where the perfusion cannulae irrigate the maternal side of the placenta. Time-radioactivity curves reached an early peak and remained the same as did their distribution on delayed scans. The 15 to 30 micron microspheres injected into the intervillous spaces are not removed onto the venous side by maternal flow through arteriovenous communications (or 'shunts') but are retained in localized areas of the intervillous space adjacent to the spiral arteries. Many of these microspheres adhere to the 'brush border' of the chorionic villi syncytiotrophoblast. These comparative studies confirm that rhesus monkeys and perfused human placental lobules are relevant models to investigate uteroplacental hemodynamics.

Animals↗