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Biomedical subjects

I Nathanson

Publications and source records attributed to I Nathanson.

15 recordsLinked to original sources
PubMed1994

Measurement of chloride concentration in microvolume samples of sweat.

Measuring sweat Cl concentration requires multiple steps. Following pilocarpine iontophoresis we compared Cl concentrations of sweat obtained on gauze pads to microvolumes (5 microL) collected into capillary tubes (N = 111). Chloride concentrations obtained by these two methods correlated significantly (r = 0.95; P < 0.001), indicating that Cl concentration can be measured accurately and easily on small volumes.

Chlorine↗
PubMed1991

Ultrafast computerized tomography of the chest in cystic fibrosis: a new scoring system.

Assessing the presence and severity of bronchiectasis (BR) and mucoid impaction (MI) of the airways in cystic fibrosis (CF) is difficult by non-invasive methods. We hypothesized that scoring ultrafast computerized tomograms (UFCT) of the chest for BR and MI could be useful in detecting early lung changes in 28 patients with CF. To do this, UFCT scores were compared to established clinical and chest X-ray (CXR) scores. Results showed that UFCT scores correlated highly with clinical (r = 0.88) and CXR (r = 0.93) scores, and several pulmonary function tests. Regression analysis indicated that BR influenced clinical and CXR scores more than MI. Both BR and MI were found in all areas of the lungs without a major propensity for one region, although there was significantly more BR in the right upper lobe than the right lower lobe. In patients with CXR score greater than or equal to 21 BR was present in 8/9 and MI in 3/9, while in those with CXR score less than 21 UFCT showed BR in 19/19 and MI in 17/19. We conclude: 1) scored UFCTs correlate well with CXR and clinical scores; 2) BR influences clinical and CXR scores more than MI; 3) UFCTs detect BR and MI in CF patients with minimal evidence of pulmonary disease; and 4) CXR scores less than 21 reflect the presence of both BR and MI.

Adolescent↗
PubMed1989

Cardiorespiratory patterns during alarms in infants using apnea/bradycardia monitors.

Evaluating the significance of alarms at home in infants monitored for apnea/bradycardia depends on subjective parental observations. Retrospective analysis of 165 event recordings made during alarms in 90 monitored infants indicated that alarms were due to prolonged (greater than 15 s) apnea (6%), bradycardia (14%), shallow breathing (19%), mechanical malfunction (55%), or other causes (6%). Also, 68 infants had pneumograms. Of the 37 infants with an abnormal pneumogram, 14% had an abnormal event recording. Of the 31 infants with a normal pneumogram, 16% had an abnormal event recording. All monitors were discontinued without complication after a negative event recording. It may be concluded that (1) event recordings can document cardiorespiratory patterns during alarms, (2) the majority of alarms occurring at home are not significant, and (3) pneumograms do not appear to indicate which infants are at risk for a future significant alarm.

Apnea↗
PubMed1988

Relationship between leukotriene C4 and an uteroglobin-like protein in nasal and tracheobronchial mucosa of children. Implication in acute respiratory illnesses.

Secretions from the nose and nasopharynx (NPS) are more readily accessible than tracheobronchial secretions (TBS) for clinical investigations, but it is unclear whether changes in mediator release in the nasopharynx reflect similar changes in the tracheobronchial tree. In order to clarify this question, NPS and TBS were taken from 20 children with tracheotomy and tested for the presence of leukotriene C4 (LTC4) and uteroglobin-like protein (UTG-LP). LTC4 and UTG-LP were measured both when the children were healthy and when they had clinical evidence of an acute respiratory tract illness. The mean concentration of LTC4 in NPS and TBS increased during illness although the mean concentration in NPS was significantly higher than in TBS during respiratory illness. In healthy children UTG-LP was detected only in TBS. During acute respiratory illness the concentration of UTG-LP in TBS decreased but remained significantly higher than in NPS. Data presented in this study indicate that changes in the LTC4 concentration in NPS appear to reflect changes in LTC4 concentration in TBS although the levels of LTC4 in NPS were significantly higher than in TBS. An inverse correlation between the concentrations of LTC4 and UTG-LP in NPS and TBS was demonstrated.

Acute Disease↗
PubMed1983

Effects of amphotericin B on ion and fluid movement across dog tracheal epithelium.

Ion fluxes or fluid flow were measured across sheets of dog tracheal epithelium mounted in Ussing chambers or a special apparatus, respectively. Under short-circuit conditions, luminal amphotericin B (3 X 10(-5) M) caused an inhibition of net Cl secretion and an increase in net Na absorption across paired tissues. In paired tissues under resting open-circuit conditions, there was no significant net transepithelial flux of either Cl or Na. Amphotericin B induced significant net fluxes of both Cl and Na toward the serosal side. In separate tissues from the same animals, there was no significant transepithelial fluid movement under resting conditions. Amphotericin B caused a net absorption of fluid. The absorption of salt and fluid in amphotericin B-treated tissues was abolished by ouabain. We conclude that stimulation of active Na transport by amphotericin B leads to fluid absorption. In vivo, the movement of fluid across the dog tracheal epithelium may be dependent on a balance between active Cl secretion and active Na absorption.

Amphotericin B↗
PubMed1983

Effect of vasoactive intestinal peptide on ion transport across dog tracheal epithelium.

Under short-circuit conditions, vasoactive intestinal peptide (VIP) did not alter net Na+ movement but selectively stimulated net Cl- secretion across dog tracheal epithelium with a high affinity (Km congruent to 10(-8) M). The increase in Cl- secretion was not different from the rise in short-circuit current (Isc). However, stimulation of Cl- secretion was not maximal, because the addition of isoproterenol (10(-6) M) to VIP-treated tissues further increased the Isc by 54%. The effect of exogenous VIP was not blocked by a combination of atropine, phentolamine, propranolol (10(-5) or 10(-6) M), or tetrodotoxin (10(-6) M). Under open-circuit conditions, VIP caused an increase in the net secretion of Cl- and Na+, but the changes did not reach statistical significance. We conclude that VIP acts directly on receptors on the surface of epithelial cells to stimulate active Cl- secretion. The abundance of VIP nerves in the submucosa suggests that VIP may be important in regulation of fluid movement across the epithelium.

Animals↗
PubMed1980

Pulmonary hypertrophic osteoarthropathy in cystic fibrosis.

A survey was carried out in 40 patients with cystic fibrosis to determine how many of them showed evidence of pulmonary hypertrophic osteoarthropathy (PHOA) and whether pulmonary function abnormalities, sputum cultures, or a history of joint or bone symptoms could be used to aid in its diagnosis. This survey indicates that the prevalence of PHOA is low (5%) and that these laboratory and clinical criteria do no appear to predict which patients are at risk for PHOA.

Adolescent↗