Biomedical subjects
Publications and source records attributed to D Nielson.
Minimally invasive excision of deep lung nodules can be difficult partly because endoscopic staplers do not open wide enough. We describe a method in which a standard atraumatic straight clamp compresses the lung to allow placement of the stapler without difficulty.
All calves fed locoweed (green and dry Oxytropis sericea Nutt and dry Astragalus lentiginosus Dougl) at high elevation developed clinical signs, gross and microscopic lesions of congestive right heart failure. Clinical signs and microscopic lesions of locoweed intoxication were also evident. Control calves did not develop the clinical signs, gross or microscopic lesions demonstrated in the locoweed fed calves.
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We have found that skin surface electrodes for continuously measuring oxygen (PSO2) and carbon dioxide (PSCO2) tensions provide reliable means of determining whether infants with apnea due to airway obstruction during sleep require treatment. Nine patients referred for evaluation of aqnea during sleep were studied. In 6 patients with PSO2 less than 50 torr during sleep, the hypoxic episodes were clearly associated with partial or total airway occlusion as judged by increasing respiratory effort without concomitant airflow. PSCO2 was found to increase during the episodes of obstruction in all 6 patients. These patients were treated with 1. tracheotomy, 2. tonsillectomy and adenoidectomy in 2 patients, 3. bilateral mandibular condylotomies, 4. pharyngeal flap release, and 5. discontinuing topical nasal decongestants. After treatment, all had decreased hypoxia, hypercarbia, or airway obstruction. Two of the remaining 3 patients had no alterations of PSO2 or PSCO2 associated with airway obstruction during sleep. The third exhibited hypoxia and hypercarbia secondary to central apnea. We conclude, therefore, that continuous monitoring of skin surface oxygen and carbon dioxide tensions is useful in evaluating children with obstructive sleep apnea.
Gil and Weibel (1972) have demonstrated the importance of alveolar recruitment at relatively low inflating pressures, which has also been noted by Klingele and Staub (1970). These findings are incorporated into a model of alveolar mechanics which presents a possible solution to the questions concerning the classical theory of PV hysteresis which are raised by the mercury filled lung and the Tween 20 rinsed lung experiments. A mathematical model was used to test the hypotheses and curves consistent with the experimental data are generated by a small computer. It is concluded that according to the model, the classical theory of PV hysteresis is valid under normal physiologic conditions but alveolar recruitment and de-recruitment become important factors in alveolar mechanics under conditions of alveolar instability.
Type 1 diabetes is an autoimmune disease characterized by immune-mediated destruction of the pancreatic beta cells. Insulin autoantibodies (IAAs) develop in many subjects at high risk for developing type 1 diabetes prior to onset of clinical disease and exposure to exogenous insulin, whereas insulin antibodies (IAs) commonly develop in patients treated with exogenous insulin. To investigate whether the binding characteristics of IAA and IA are similar, we measured eight different binding characteristics of IAAs from 19 insulin-naive first-degree relatives of type 1 diabetes patients and compared these to the binding characteristics of IAs from 19 type 1 diabetes patients treated with exogenous insulin. IAA and IA samples were matched for percentage insulin binding. Scatchard analysis revealed that IAAs have a two-slope representation similar to IAs-that is, two populations of antibodies, a high-affinity low-capacity population and a low-affinity high-capacity population. Binding properties of the two respective populations were found to be similar for IAAs and IAs. Sipps' equation was used to generate a Hill plot and produce an index of heterogeneity, which showed further similarity between IAAs and IAs. These results suggest that the IAAs found in subjects at increased risk for type 1 diabetes, like IAs, are likely to be polyclonal in nature. The similarities between IAAs and IAs support the hypothesis that both are induced by insulin presentation to the immune system.