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Biomedical subjects

A P McDonald

Publications and source records attributed to A P McDonald.

7 recordsLinked to original sources
PubMed1987

Identification of herniated nucleus pulposis in spinal cord injury.

Five cases of documented traumatic herniated nucleus pulposis are presented all occurring within the cervical region. The incidence of herniated disc in cervical spinal cord injury is 0.7%. The incidence of herniated disc in bilateral facet dislocations is 2.3%. The common features are radicular pain, incomplete syndrome, and bilateral facet dislocations. A routine myelogram is the most helpful test to establish the diagnosis.

Adult↗
PubMed1983

99mTc-labeled solid-phase meal: a quantitative clinical measurement of human gastric emptying.

A solid-phase meal labeled with 99mTc-sulfur colloid provides an improved clinical test for the quantitative evaluation of human gastric emptying. We studied 12 healthy male controls and five male patients with known gastric stasis secondary to a vagotomy and drainage procedure. All subjects were fasted for 8 hours before the study, and each consumed an unbuttered biscuit and a poached egg white containing 1 mCi of 99mTc-sulfur colloid. For 2 hours, 60-second counts were measured every 10 minutes by a Pho Gamma III scintillation camera. The t1/2 for control subjects was 60 minutes, at which time patients with gastric stasis had retained 98% of the test meal. At 120 minutes, control subjects and patients with gastric stasis had 4.7% and 89%, respectively, of the meal remaining in the stomach. The solid-phase test meal labeled with 99mTc-sulfur colloid is easy to perform and can be used clinically to quantitatively measure gastric emptying in humans. This test can discriminate between control subjects and patients with known gastric stasis.

Bread↗
PubMed1982

Demonstration at the single-cell level of the existence of distinct clusters of epitopes in two predefined human Ia molecular subsets.

The expression at the cell surface level of two previously defined human Ia antigen subsets, NG1 and NG2, was studied. Two monoclonal hybridoma antibodies, D1-12 (anti-NG1) and D4-22 (anti-NG2), labeled with distinct fluorochromes, were used as probes. The results indicate that NG1 and NG2 molecules are simultaneously expressed on the same cell, and moreover, that they are identifiable as spatially separate structures. In addition, when a series of 6 other anti-Ia monoclonal antibodies previously described were analyzed in a checkerboard test of binding inhibition at the cell surface level, they were found to closely mimic the reactivity pattern of either D1-12 or D4-22 antibody, suggesting that NG1 and NG2 Ia subsets express independent clusters of highly immunogenic epitopes.

Antibodies, Monoclonal↗
PubMed1979

Morphologic and functional effects of esophageal cryotherapy.

With advances in equipment design, cryotherapy has been applied increasingly in the management of various integumentary disorders. Recently, endobronchial cryotherapy has been utilized in the treatment of acquired tracheal strictures. To evaluate the effects of cryotherapy upon the esophagus, we cooled the distal esophagus of 12 cats to -70 degrees to -80 degrees C. for 2 minutes with a specially constructed cryoprobe. The animals were put to death in pairs 90 minutes, 4 days, 10 days, 14 days, 28 days, and 42 days following cryotherapy. Immediately prior to sacrifice, all animals were studied with esophageal cinefluoroscopy and esophageal manometrics. All animals tolerated this degree of cryotherapy and gained weight on an ad libitum diet. Manometric studies demonstrated diminished amplitude of peristalsis immediately following cryotherapy, but prompt return to a normal manometric pattern. There was no evidence of esophageal dysfunction on esophageal cinefluoroscopy. Morphologic examination demonstrated superficial ulceration between 4 and 10 days following cryotherapy, with subsequent healing. The esophagus in animals put to death 28 and 42 days following cryotherapy appeared histologically normal. These studies demonstrate the safety of cryotherapy to -70 to -80 degrees C. upon the esophageal wall and suggest investigation of the usefulness of this modality in the treatment of local esophageal webs and strictures.

Animals↗