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Biomedical subjects

C Mittman

Publications and source records attributed to C Mittman.

At least 19 recordsLinked to original sources
PubMed1992

Reversibility of airways injury over a 12-month period following smoking cessation.

In this investigation, we examined changes in exfoliated tracheobronchial cells in sputum in 46 individuals (mean age = 49.2 years; mean packyears = 48.7) who discontinued smoking and 37 individuals (mean age = 54.9 years; mean packyears = 65.2) who continued to smoke over a 12-month period after participation in the St. Helena Hospital and Health Center one-week residential smoking cessation program. Before the beginning of the smoking cessation program, those who went on to quit were not different from those who did not quit with respect to baseline cytomorphology ratings. In those individuals with a minimum of three follow-up tests, results indicated significant reductions from precessation levels in macrophages, pigmented macrophages, and neutrophils after adjustment for differences in age, packyears, and pulmonary function (FEV1/FVC). Over the course of follow-up, quitters, in comparison with nonquitters, also had significantly lower mean levels of columnar cells, mucus, mucous spirals, and metaplasia. These results indicate a consistent effect of smoking cessation on cytomorphology and demonstrate that on cessation, some of the measured elements promptly return toward a more normal pattern.

Forced Expiratory Volume↗
PubMed1988

Bolus technique for assessing distribution of inspired gas during tidal breathing.

The washout of an insoluble tracer from the lung may be represented by a model with two ventilatory compartments representing poorly and better-ventilated regions. Using boli of a second insoluble gas delivered at a given point during inspirations of a multibreath washout test, the proportions of labeled inspired ventilation reaching the poorly and well-ventilated regions may be determined by analyzing the kinetics of the exhaled tracer. We studied eight normal subjects breathing through large-bore solenoid valves controlled to maintain tidal volume at 600 or 900 ml. Boli consisting of 15 ml of 80% He-20% O2 were delivered over 75 ms; this labeled approximately 125 ml of inspired gas. Boli were delivered after 50 ml had been inspired to mark early inspiration and after 300 ml had been inspired to mark midinspiration. Using 900-ml tidal breaths, late inspiration was marked by boli delivered at 600 ml. Subjects were studied in the seated and the supine positions. In both positions, significantly more of the early breath went to the poorly ventilated compartment. Several possible physiological mechanisms, singly or in combination, could account for these observations, but differences in dead space path length are most likely involved.

Adult↗
PubMed1986

Aging of the lungs: speculation on the role of oxidants and proteases.

In most regards, aging of the human lungs mimics the development of emphysema. Various lines of evidence suggest that oxidants and proteases play an important role in the pathogenesis of emphysema. The disease seems to arise through a complex interplay of genetic and environmental factors. This paper explores the possibility that normal aging of the lungs, as it has been defined by various cross-sectional and longitudinal studies, is part of a pathological continuum ending with frank emphysema. It is not clear if these are "normal" aging effects or the result of the accumulation of disease.

Aging↗
PubMed1985

A new pendant storage oxygen-conserving nasal cannula.

With increasing interest in reducing the cost of oxygen therapy, we recently designed an oxygen-conserving cannula. It reduces the oxygen supply flow necessary to achieve adequate oxygen saturation, but because it requires the use of a reservoir situated under the nose, some patients find it obtrusive. We therefore designed a similar system but displaced the reservoir away from the face and onto the anterior chest wall where it could be hidden from view by the patient's clothing. We evaluated this pendant conserving nasal cannula (PNC) in seven hypoxemic patients with chronic obstructive pulmonary disease. We compared oxygen saturations achieved using the PNC vs the standard steady flow nasal cannula (SNC) at 0.5 through 4 L/min. The mean improvement in oxygen saturation using the PNC vs the SNC was 3.3 percent at 0.5 L/min, 4.3 percent at 1 L/min and 3.1 percent at 2 L/min. These differences were statistically significant (p less than 0.001). The saturation achieved by the PNC at 0.5 L/min was equivalent to that achieved by the SNC at 1.8 L/min. We conclude that the PNC provides effective oxygen delivery to patients at supply flows substantially less than the SNC. The device is aesthetically acceptable to patients and its widespread use in patients requiring chronic oxygen therapy could bring about significant financial savings.

Adult↗
PubMed1984

Collaborative study to assess risk of lung disease in Pi MZ phenotype subjects.

We studied 143 Pi MZ heterozygous (MZ) subjects from random populations that had been examined previously for alpha 1-antitrypsin phenotype. Each Pi MZ subject was closely matched with a Pi M control subject from the same population at each of 6 centers. An expanded National Heart, Lung and Blood Institute (NHLBI) respiratory symptom questionnaire was completed by each subject. Pulmonary function tests designed to detect established as well as early obstructive airway abnormalities were administered. Multivariate analysis of the variance of data from the questionnaire and pulmonary function tests corrected for age, race, sex, and smoking history showed no significant difference (p less than 0.05) between subjects of Pi MZ and Pi M phenotype. The size of the populations studied and number of observations made for each variable were sufficient to assure that small differences could be detected with 95% power. We conclude that MZ phenotype alone carries no greater risk of developing lung disease than M phenotype.

Adult↗
PubMed1982

Optimal inputs for parameter determination of inert gas washout from the lung.

The nitrogen washout test will yield more information about the distribution of pulmonary ventilation if a pattern of inspired gas concentrations is utilized other than the standard series of 100% oxygen breaths. The input breathing pattern which yields optimal results will vary with the specific features of the lung being studied but typically includes breaths of air, particularly in the last third of the washout. Using computerized, mathematical techniques, optimal inputs were selected for washout tests of duration 10, 20, 30 and 40 breaths for each of six lung models, ranging from a unicompartmental to a highly non-uniform 'diseased' lung. Knowing these optimal inputs we were able to devise a nominal input which was similar to the optimal inputs for all models. For a 10 breath test this nominal input pattern utilized a breath of air at breath 7. For a 20 breath test, air is utilized at breaths 12, 14, 15, 19; for 30, air at 19, 21, 22, 23, 29 and for a 40-breath test, air at breaths 19, 24, 28, 30, 31, 32 and 39. The 30-breath nominal sequence was compared with the conventional oxygen-only washout and a 31-breath pseudo-random binary (PRB) input. Comparisons were made using computer simulated washouts as well as actual tests on human subjects. The 30-breath nominal input was always superior to the standard washout and was superior to the PRB input for all models except the lung ventilated with vital capacity breaths. We conclude that a significant advantage is gained by substituting the recommended sequences of breaths in studies of the dynamics of gas exchange in the lung.

Humans↗
PubMed1976

Antitrypsin.

Explore the source record for details and available documents.

Genetics, Medical↗
PubMed1975

A simplified method for measuring helium closing volume.

A simple method for delivering a constant volume of helium for the measurement of airway closing volume is described. Using a standard fiveway valve and PVC plastic irrigation pipe, a device was constructed which permits the delivery of a uniform volume of helium and avoids the troublesome valve change during inspiration. Results obtained when using this device were comparable to those with the use of conventional bag to contain the helium.

Helium↗