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Biomedical subjects

J Seltzer

Publications and source records attributed to J Seltzer.

31 records · Page 2Linked to original sources
PubMed1987

Antidiuretic hormone excess in infant botulism.

Two infants developed evidence of antidiuretic hormone excess as a complication of infant botulism. Neither child received mechanical ventilatory support before the development of hyponatremia, serum hyposmolality, and urinary hyperosmolality. Both infants responded to fluid-intake restriction. The appearance of hyponatremia in an infant with botulism should suggest antidiuretic hormone excess. The recognition of this entity will lead to its appropriate management with fluid-intake restriction.

Botulism↗
PubMed1987

Chronic exposure to sulfur dioxide. Physiologic and histologic evaluation of dogs exposed to 50 or 15 ppm.

Seven adult mongrel dogs were exposed to SO2 gas at 2 different concentrations (15 and 50 ppm) on a daily basis for 5 to 11 months. Mucous hypersecretion and airway obstruction (a sustained increase in pulmonary resistance) developed in 4 dogs exposed to 50 ppm SO2. Histologic examination of the dogs' airways demonstrated epithelial thickening and an increase in size of the mucous glands. No inflammatory cell infiltration of the airways was noted and, in addition, responsiveness to inhaled histamine and methacholine did not change. The increase in lung resistance correlated with increase in mucous gland volume and airway wall thickening, but not with any change in airway responsiveness. Dogs exposed to 15 ppm SO2 showed minimal histologic and physiologic changes compared with control dogs. Previous work with a similar model of chronic bronchitis, using higher level SO2 exposure, has demonstrated an association of airway inflammation with decreased responsiveness to inhaled bronchoconstrictors. In the present study, with a lower exposure level to SO2 (50 versus 200 ppm), we found similar histologic findings associated with airway obstruction, but in the absence of airway inflammation, responsiveness to inhaled bronchoconstrictors was unchanged. This supports the theory that chronic airway inflammation may be associated with decreased responsiveness to inhaled bronchoconstrictors. This contrasts with the hyperresponsiveness induced by acute exposure to irritant gases noted by others.

Airway Resistance↗
PubMed1986

O3-induced change in bronchial reactivity to methacholine and airway inflammation in humans.

The increase in airway responsiveness induced by O3 exposure in dogs is associated with airway epithelial inflammation, as evidenced by an increase in the number of neutrophils (polymorphonuclear leukocytes) found in epithelial biopsies and in bronchoalveolar lavage fluid. We investigated in 10 healthy, human subjects whether O3-induced hyperresponsiveness was similarly associated with airway inflammation by examining changes in the types of cells recovered in bronchoalveolar lavage fluid obtained after exposure to air or to O3 (0.4 or 0.6 ppm). We also measured the concentrations of cyclooxygenase and lipoxygenase metabolites of arachidonic acid in lavage fluid. We measured airway responsiveness to inhaled methacholine aerosol before and after each exposure and performed bronchoalveolar lavage 3 h later. We found more neutrophils in the lavage fluid from O3-exposed subjects, especially in those in whom O3 exposure produced an increase in airway responsiveness. We also found significant increases in the concentrations of prostaglandins E2, F2 alpha, and thromboxane B2 in lavage fluid from O3-exposed subjects. These results show that in human subjects O3-induced hyperresponsiveness to methacholine is associated with an influx of neutrophils into the airways and with changes in the levels of some cyclooxygenase metabolites of arachidonic acid.

Adult↗
PubMed1986

Effect of tidal volume and anesthetic agent on airway responsiveness to histamine.

Dose-response relationships for bronchoconstriction in response to aerosal histamine were assessed before and after vagotomy in 11 dogs anesthetized with barbiturates and in 9 dogs anesthetized with alpha-chloralose-urethan. The dose-response relationships following vagotomy were assessed during spontaneous ventilation and during muscular paralysis and mechanical ventilation with tidal volume (VT) similar to each animal's VT prior to vagotomy. After vagotomy the spontaneous VT of both groups increased but the VT of the alpha-chloralose-urethan group was significantly less than that of the barbiturate group. The histamine responsiveness of the animals anesthetized with barbiturates was significantly greater during mechanical ventilation when VT was reduced to prevagotomy levels compared with during spontaneous ventilation. In contrast, the histamine responsiveness of the alpha-chloralose-urethan group was not significantly changed by reducing VT to prevagotomy levels. In six other dogs anesthetized with pentobarbital sodium and studied after vagotomy, responsiveness to histamine aerosol during controlled ventilation with breaths of prevagotomy VT was greater than responsiveness during mechanical ventilation with large volume breaths given immediately afterward. Thus the magnitude of VT of dogs after vagotomy may influence airway responsiveness, and the influence of anesthetic agents on airway responsiveness after vagotomy may in part be due to their effects on VT. Furthermore, bronchodilation accompanying large volume ventilation persists after vagotomy, suggesting that it is not exclusively mediated by changes in parasympathetic activity.

Airway Resistance↗
PubMed1985

Effect of eucapnic hypoxia on bronchomotor tone and on the bronchomotor response to dry air in asthmatic subjects.

Because hypoxia has been shown to cause bronchoconstriction and to potentiate bronchomotor responsiveness in animals, we investigated whether hypoxia has similar effects in subjects with asthma. We measured specific airway resistance (SRaw; the mean of 5 sequential readings taken 30 s apart) before and immediately after each of 15 asthmatic subjects breathed a mixture of 8% O2 in N2 until hemoglobin saturation (SaO2; by ear oximetry) fell to 80% or less for at least 2 min. We maintained end-tidal CO2 at resting levels, the temperature of the inspirate at 22.0 +/- 1.1 degrees C, and the dew point at 18.5 +/- 1.6 degrees C (mean +/- SD). The SaO2 fell to 70 +/- 8%; minute ventilation rose to 28.4 +/- 8.5 L/min, and heart rate rose by 27 +/- 6 beats/min. The SRaw did not increase significantly in the group (baseline SRaw, 6.61 +/- 2.36; posthypoxia SRaw, 6.69 +/- 2.21 L X cm H2O/L/s) or in any subject. To determine if hypoxia increases bronchomotor responsiveness, we also compared the responses to eucapnic hyperpnea with dry air and with dry gas mixtures of 7 to 10% O2 in N2 in a randomized, double-blind sequence in 9 of the subjects. We measured SRaw in each subject before and after stepwise increases in minute ventilation, for 3 min at each level, until SRaw doubled or until the subject's maximal voluntary ventilation was achieved. The SaO2 fell to 82% or less at each level of ventilation with the hypoxic gas mixture. The 2 stimulus-response curves thus obtained did not differ in any subject.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Density gradient study of bronchial mucus aspirates from healthy volunteers (smokers and nonsmokers) and from patients with tracheostomy.

Because it is difficult to obtain, little is known of bronchial mucus from the normal human airway; it has been mainly studied as sputum expectorated in chronic bronchitis with particular attention to epithelial glycoprotein. We have now applied density gradient methods to study this and other macromolecules and lipids in normal airway mucus. After lavage at bronchoscopy, mucus was aspirated from six normal volunteers, that include one light and two heavy smokers. This normal mucus has been compared with that obtained from four patients with tracheostomy because of respiratory muscle paralysis due to neurological disease. The normal aspirates contained small threads of mucus, the tracheostomy aspirates viscous blobs of jelly, a difference in physical appearance reflected in macromolecular yields, 0.3-1 mg/ml and 6-24 mg/ml respectively. On analytical ultracentrifugation normal mucus showed no discernible material in the buoyant density region typical of epithelial glycoprotein (1.5 g/ml): Virtually all the material migrated to the miniscus and was predominantly lipids and proteins. A trace amount of material recovered from a higher density region (greater than or equal to 1.6 g/ml) was found to contain both glycoprotein and proteoglycan. Aspirates from the heavy smokers contained appreciable amounts of material with typical buoyant density (approximately 1.5 g/ml) but still with features of proteoglycan. In contrast in tracheostomy aspirates epithelial glycoprotein of typical buoyant density and chemical composition accounted for up to 25% of nondialyzable material. We conclude that under normal conditions typical epithelial glycoprotein is virtually absent from airway mucus and that the glycoconjugate present has features of glycoprotein and proteoglycan.

Adult↗
PubMed1984

Morphologic correlation of physiologic changes caused by SO2-induced bronchitis in dogs. The role of inflammation.

Chronic bronchitis was induced in 6 mongrel dogs by exposure to SO2 gas for 6 to 18 months. All of the dogs developed cough and mucus hypersecretion. Chronic airway obstruction and decreased airway responsiveness to inhaled histamine developed in 5 of the dogs. Histologic changes in dogs evaluated after SO2 exposure included significant mucous gland hypertrophy and hyperplasia, epithelial thickening, and a decrease in the number of luminal cells containing undischarged secretory granules. Acute and chronic inflammation were found in the dogs with airway obstruction and decreased responsiveness to histamine, but such inflammation was absent in the one dog that failed to develop physiologic changes. After a period of recovery from SO2 exposure of 9 to 21 months, inflammation regressed dramatically and the other histologic changes returned toward normal. Physiologic changes regressed somewhat in those dogs that had had changes. These findings suggest that inflammation may be an important factor influencing the development of airway obstruction and altered airway responsiveness in the setting of chronic bronchitis.

Airway Resistance↗
PubMed1981

Thyroid function in chronic renal failure after successful renal transplantation.

Chronic renal failure is associated with a variety of thyroid function abnormalities. Information on thyroid function in patients with chronic renal failure after successful renal transplantation is limited. We studied thyroid function in 13 such patients and found that serum TT3 in the transplant group (136 +/- 30 ng/ml) was significantly (P less than 0.01) higher than the TT3 in the control group (112 +/- 29 ng/ml). All patients were clinically euthyroid and had normal serum TT4, FT4, FT3, TSH, and TBG levels and a normal T3 resin uptake. The pathogenesis of the observed increased TT3 in these patients is not clear.

Adolescent↗
PubMedDate not supplied

Do heated humidifiers and heat and moisture exchangers prevent temperature drop during lower abdominal surgery?

STUDY OBJECTIVE: To compare the effects of using a heated humidifier (HH), a heat and moisture exchanger (HME), or no warming device in maintaining body temperature during surgical procedures of 1 to 4 hours' duration. DESIGN: A randomized, controlled study. SETTING: Operating room, Thomas Jefferson University Hospital, Philadelphia, PA. PATIENTS: 51 ASA physical status I, II, and III patients, age 16 to 69 years, scheduled for a variety of lower abdominal procedures under general endotracheal anesthesia anticipated to last 1 to 4 hours. INTERVENTIONS: We randomly assigned patients to receiving an HH, an HME, or no warming device during the procedure. We then measured the patient's sublingual temperature every 5 minutes prior to induction, every 15 minutes intraoperatively, and every 15 minutes postoperatively until he or she was discharged from the postanesthesia care unit, (PACU). We also measured the esophageal temperature every 15 minutes intraoperatively. MEASUREMENTS AND MAIN RESULTS: Sublingual temperature or esophageal temperature probes placed at the site of maximal heart tones indicated that the patients' temperatures dropped significantly from baseline values in all three groups during the first 60 minutes of surgery, then remained constant during the next 120 minutes of surgery. Patients who had no warming device shivered and felt cold significantly more often than patients in the HH group but not more often than patients in the HME group. There was no difference in shivering between the HH and HME groups. The patients who received an HH tended to have a higher temperature (a mean of 0.5 degrees C) throughout the study, but this did not reach statistical significance. CONCLUSIONS: Results indicate that these warming devices provide little benefit in preventing a temperature drop during procedures of 1 to 4 hours' duration, although patients with an HH tended to have a higher temperature than those with an HME or no device.

Abdomen↗