Function of the isolated paced diaphragm and the cervical accessory muscles in C1 quadriplegics.
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Biomedical subjects
Publications and source records attributed to J T Sharp.
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One hundred thirteen patients with 120 episodes of septic arthritis were seen during a 14-year period. The most common bacteria cultured from joint fluid or blood during the acute episodes were gonococci, staphylococci, and streptococci. Seventeen other bacteria were the infecting organisms in one or more cases each. Other infections and medical conditions frequently were present. In some instances the septic arthritis was a complication of another infection. In other patients septic arthritis appeared to occur because of diminished resistance to infection. The majority of patients responded well to medical treatment, but eight died and 26 had persistence of articular pain at follow-up examination.
Tilt-table polygraphic study in four patients with Shy-Drager syndrome demonstrated periodic apnoea in the erect posture. In one patient reduced hypercapneic ventilatory response and necropsy findings of neuronal loss and astrocytosis in the pontine tegmentum suggested dysfunctional respiratory neurones in the brainstem. One patient had Cheyne-Stokes respiration during the late stage of the illness.
In anesthetized dogs studied both supine and prone, the electromyogram (EMG) of the diaphragm recorded directly from three portions of the diaphragm (crural, anterior, and costal) was compared with simultaneous recordings of the diaphragmatic EMG recorded from 10 sites in the esophagus and stomach. Effects upon the EMG of lung volume change and esophageal electrode position change were determined during bilateral supramaximal tetanic phrenic stimulation with airway occluded. Lung volume change had little effect upon the directly recorded EMG. The effect of lung volume change upon the EMG recorded from the esophagus was somewhat greater and marked change was noted as the esophageal recording site was varied. In supine dogs two sites of maximal signal were observed, one 1 cm above the cardia and the other 4--6 cm below the cardia. In prone dogs a single site for maximal signal was observed 3 cm above the cardia. An electrode site as close to the cardia as possible appears to be optimal from the point of view of variation in signal due to lung volume change and due to body position change. Gastric balloon stabilization is recommended. Proximity of the electrode and posterior gastric wall to the diaphragmatic crura may explain the maximal EMG signal recorded below the cardia.
With a linearized respiratory magnetometer, measurements of anteroposterior and lateral diameters of both the rib cage and the abdomen were made at functional residual capacity and continuously during tidal breathing. Twenty-five subjects with normal respiratory systems were studied in the sitting, supine, lateral decubitus, and prone body positions. When subjects changed from sitting to supine position anteroposterior diameters of both rib cage and abdomen decreased while their lateral diameters increased. Both anteroposterior and lateral tidal excursions of the rib cage decreased; those of the abdomen increased. When subjects turned from supine to lateral decubitus position both anteroposterior diameters increased and the lateral diameters decreased. This was associated with an increase in both lateral excursions and a decrease in the abdominal anteroposterior excursions. Diameters and tidal excursions in the prone position resembled those in the supine position. Diameter changes could be explained by gravitational effects. Differences in tidal excursions accompanying body position change were probably related to 1) differences in the distribution of respiratory muscle force, 2) differences in the activity or mechanical advantage of various inspiratory muscles, and 3) local compliance changes in parts of the rib cage and abdomen.
The respiratory magnetometer method of Konno and Mead was used to measure separately the rib cage and the diaphragm-abdomen components of the total respiratory system compliance in 11 subjects with normal respiratory systems. Measurements made in the awake, relaxed state by the method of Heaf and Prime were compared with similar measurements made in the anesthetized, paralyzed state by the supersyringe method. The rib cage component was greater in the paralyzed than the relaxed state in 9 of 11 subjects, but the diaphragm-abdomen component was greater in the relaxed than the paralyzed state in 8 of 11 subjects. We believe that these differences can be explained by respiratory muscle activity in the presumed relaxed state. The fraction of the tidal volume attributable to rib cage displacement compared to abdominal displacement was greater during mechanical ventilation in the paralyzed state than during awake, spontaneous breathing. This can be explained by the different distribution of inflating forces produced by diaphragmatic contraction compared to positive airway and alveolar pressure, in particular by the very different patterns of diaphragmatic displacement in the 2 states.
In a double-blind, crossover study, naproxen, 250 mg twice a day, naproxen, 500 mg taken at bedtime, and indomethacin, 25 mg four times a day, were compared in 132 patients with rheumatoid arthritis; six centers participated in the study. Objective indices of arthritis activity, such as number of clinically active joints, walking time, and duration of morning stiffness, were nearly identical for the three treatment regimens. Of particular interest was the observation that efficacy of a single daily dose of naproxen was comparable to that of the twice-daily dosage. Naproxen was better tolerated than indomethacin, as shown by a statistically significant difference in the incidence of CNS complaints.
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Some cases presently classified as multicentric reticulohistiocytosis may represent unusual manifestations of tuberculosis. Antituberculous chemotherapy may be justified in patients who have clinical and histopathologic evidence of multicentric reticulohistiocytosis in association with a positive tuberculin skin test.
A patient with systemic lupus erythematosus (SLE) and a patient with an immune complex disease resembling Goodpasture's syndrome were treated with cyclophosphamide, prednisone and repeated plasma exchanges. Circulating immune complexes decreased, and symptoms of central nervous system disease remitted for up to 15 to 20 days after plasma exchange in the patient with SLE. In vitro lymphocyte blastogenic responses to antigens were also transiently increased on two occasions following treatment. In the second patient, decreases in circulating immune complexes and clinical improvement were ascribed chiefly to immunosuppressive drug treatment. Serum antibody to keyhole limpet hemocyanin was relatively unaffected by plasma exchange in both patients. These results suggest that plasma exchange may help to deplete circulating immune complexes or alter the equilibrium between soluble antigen and antibody which causes complexes to form and circulate. It may be less effective in reducing circulating antibody levels in patients who continue to produce new antibody.
Results of serologic tests in rheumatic disease require good judgment in interpretation, based upon familiarity with the present knowledge of immunologic mechanisms, including the action of antibodies, auto-antibodies, T-cells and B-cells.
Cell-mediated immunity in rheumatoid arthritis (RA) was assessed by skin testing with six antigens in 107 patients, 94 of whom were age, sex, and race-matched with healthy individuals or patients with diseases unrelated to immunological abnormalities. 20% of RA patients were anergic. Impaired cell-mediated immunity in the RA patients was manifested by a decrease in the magnitude of skin reactivity as well as a decrease in the incidence of positive reactions to multiple antigens. Depression in cell-mediated immunity was related to age but not to sex, duration of disease, or disease activity. A slight correlation was found between absolute peripheral lymphocyte counts and the number of positive skin tests, and was confirmed by finding an association between lymphocyte counts and the size of skin reactions. A correlation was also found between lymphocyte counts and disease activity. Four explanations of the observed depression in cell-mediated immunity in RA were considered: (1) a preoccupation of the immune mechanism of the host with cell-mediated immunity reactions related to the pathogenesis of the disease; (2) a depression of cell-mediated immune reactivity by a virus infection; (3) depression of cell-mediated immunity by therapy; and (4) immune complex suppression of cell-mediated immunity. No effect of gold therapy was found. The near universal use of salicylates or other anti-inflammatory drugs did not permit investigation of the effect of these drugs on cell-mediated immunity.
Studies of thoracoabdominal motion using the respiratory magnetometer were performed in 30 patients with chronic obstructive pulmonary disease. Volume equivalency of thoracic and abdominal deflections was established by using the concepts and methods developed by Konno and Mead. Twenty patients were ambulatory, although disabled, and 10 were in acute respiratory failure and were studied in a respiratory intensive care unit. Five of 20 ambulatory patients and 8 of 10 patients in acute respiratory failure showed inward abdominal motion coincident with outward rib cage motion during inspiration, suggesting ineffective diaphragmatic function. This pattern of thoracoabdominal motion was identical to that seen in 2 high quadriplegics with diaphragmatic paralysis when they were breathing entirely with their neck muscles. Inspiratory ascent of the diaphragm was confirmed fluoroscopically in 3 of the 5 ambulatory patients. Patients showing this pattern were generally severely disabled and had the largest residual volumes. Two abnormal patterns of thoracoabdominal motion were observed during the performance of maximal voluntary ventilation in the ambulatory patients. The first, seen in 9 of 20 patients, was characterized by reciprocal or paradoxical motion of rib cage and abdomen, with increase in rib cage volume associated with decrease in abdominal volume during inspiration. The second pattern, seen in 5 of 20 patients, showed complete disorganization of rib cage and abdominal motion, with no consistent or reproducible pattern. Thus, a significant proportion of patients with disabling chronic obstructive pulmonary disease show abnormalities in thoracoabdominal motion that are observable with the respiratory magnetometer and ofter by simple inspection. Most of these abnormalities suggest malfunction of respiratory muscles, particularly the diaphragm.
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An association between viral hepatitis and two rheumatic disease syndromes has been observed. Twenty-nine patients manifested a transient polyarthritis, sometimes associated with a rash (Group I). Ten patients were seen with a multisystem disease (Group II). Histologic evidence of arteritis or glomerulonephritis was present in seven of ten patients with multisystem disease. Liver tissue from 18 patients showed morphologic evidence of hepatitis with viral features in 9 of 10 patients in Group I and in 6 of 8 patients in Group II. Hepatitis B surface antigen (HBsAg) and/or antibody to HBsAg were detected in sera of all 39 patients. Abnormal liver functions were present in 36. Twelve Group I patients and 2 Group II patients became jaundiced. Rheumatoid factor was present in sera of seven patients in each group. The third component of complement (C3) was depressed in 13 patients in Group I and 7 patients in Group II. The fourth component of complement (C4) was decreased in 8 of 21 Group I and 3 of 7 Group II patients. Synovial fluid C3 was decreased in 2 of 11 Group I and 1 of 4 Group II patient's fluids. Articular inflammation in patients with transient polyarthritis responded in three to seven days to aspirin, acetominophen and/or bedrest alone and rashes disappeared spontaneously. Patients with multisystem disease generally had a prolonged illness and responded somewhat unpredictably to prednisone or a combination of prednisone and cyclophosphamide.