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Biomedical subjects

J Conklin

Publications and source records attributed to J Conklin.

15 recordsLinked to original sources

When it's hard to swallow. What to look for in patients with dysphagia.

Swallowing disorders can be divided into oropharyngeal dysphagia and esophageal dysphagia. The most common cause of oropharyngeal dysphagia is cerebrovascular accidents; other causes may include oropharyngeal structural lesions, systematic and local muscular diseases, and diverse neurologic disorders. Esophageal dysphagia may result from neuromuscular disorders, mortality abnormalities, and intrinsic or extrinsic obstructive lesions. Through clinical history taking helps define the tpe of dysphagia and can guide diagnostic testing. Important questions to ask patients with the disorder include specific features of the dysphagia, its onset and progression, accompanying problems, and eating habits adopted to relieve symptoms. Videofluoroscopy should be the initial test in evaluating oropharyngeal dysphagia. Barium-contrast esophagography identifies most anatomic causes of dysphagia and some motor disorders and is better tha endoscopy at identifying extrinsic esophageal compression and intramural lesions not involving the esophageal mucosa. Cine-esophagography may provide clues to a possible esophageal motor disorder causing dysphagia. Endoscopy is the test of choice if obstruction or gastroesophageal reflux disease is suspected, because biopsies can confirm the presence of esophagitis and provide specific pathologic identification of the obstructive lesion. In addition, therapeutic dilatation of a stricture and removal of foreign bodies can be accomplished as part of the evaluation procedure. When no obvious source of dysphagia is apparent after radiologic and endoscopic assessment, manometry for possible motility disorder should be considered.

Deglutition

Penetrating keratoplasty for corneal perforation in an obtunded patient.

A ventilator-dependent patient obtunded from severe head trauma suffered a spontaneous corneal perforation with lens extrusion secondary to nosocomial Pseudomonas keratitis. Despite the patient's guarded condition, a successful tectonic penetrating keratoplasty with lens removal was performed for restoration of the globe. Upon recovery, the patient's only useful vision was in her operated eye. Preventative measures against prolonged corneal exposure in an obtunded patient include copious artificial tears and lubricants, use of scleral lenses, moisture chambers, bandage contact lenses, or tarsorrhaphies.

Aged

Receptor-selective localization in pancreas.

We examined the distribution of three tritiated ligands and two radioiodinated ligands for their ability to localize in the pancreas of rat and rabbit. The ligands examined are selective for the alpha- and beta-adrenoceptors and the muscarinic acetylcholine receptor. Of the ligands examined, the results indicate that only (R) 3H-3-quinuclidinyl benzilate (QNB) localized in the pancreas by the receptor-mediated mechanism. The % dose/g tissue, the pancreas-to-blood and pancreas-to-liver ratios are such that a 18F-labeled derivative of QNB should provide images of the pancreas.

Adrenergic beta-Antagonists

In vivo competition studies with analogues of 3-quinuclidinyl benzilate.

Among ligands that bind to the alpha- and beta-adrenoceptors and to the muscarinic acetylcholine receptor (m-AChR), those that bind to the latter have the best properties for external detection of receptor sites by gamma-camera imaging. To develop the optimal radiotracer, nonradioactive analogues of 3-quinuclidinyl benzilate (I) were tested in in vivo displacement studies with (-)-[3H]I to determine their ability to compete with (-)-[3H]I for the muscarinic acetylcholine receptor. There is a linear correlation between the ability to compete with (-)-[3H]I for the m-AChR and the affinity constant of the analogue as determined by in vitro assay, suggesting that the test is a valid indicator of in vivo distribution. One radioiodinated analogue, 3-quinuclidinyl p- iodobenzilate , bound to m-AChR in the heart and brain of rats.

Animals

Computer-aided medical decision making in radiotherapy.

Radiotherapy departments are becoming sophisticated in working with computers for isodose computations, treatment machine verifications and administrative and medical records. The next step lies in computer-assisted medical decision making. The logic for a patient's diagnostic work-up and treatment protocol can be stored in a computer. It can then be used as an aid in making the diagnosis, in prescribing the treatment and for quality control. For patients who fit established protocols the computer can select and list treatment using the logic of that protocol. Such a system has been implemented for the postoperative radiotherapy of breast cancer on a trial basis. Its potential usefulness is illustrated by results in 25 consecutive patients. Physician acceptance and costs of the program are under investigation.

Breast Neoplasms