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Biomedical subjects

M A Cohn

Publications and source records attributed to M A Cohn.

35 records · Page 2Linked to original sources
PubMed1984

The effects of brotizolam, a new hypnotic, on cardiac and respiratory function in volunteers.

In a double-blind, cross-over study we measured the effect of a 0.5-mg oral dose of brotizolam, a new thienodiazepine hypnotic, on cardiac and respiratory functions in 12 healthy volunteers. No deleterious effects on pulse, blood pressure, forced vital capacity, forced expiratory volume in 1 s, respiratory rate, mouth occlusion pressure (P0.1) and ventilatory responses to carbon dioxide occurred over a 6-hour period. In the usual therapeutic dose, brotizolam does not suppress cardiac and respiratory functions in healthy volunteers.

Adult↗
PubMed1983

Seed Dormancy in Red Rice : III. Response to Nitrite, Nitrate, and Ammonium Ions.

Sodium nitrite at 10 millimolar breaks dormancy of dehulled red rice (Oryza sativa). While germination is light independent, low pH conditions (pH 3) are required for maximum response. Water and buffer controls at pH 3 remain dormant. The response to nitrite occurs at 25 and 30 degrees C but is reduced at 20 degrees C, although nondormant seeds germinate readily at this temperature. The contact time for response to nitrite is less than 2 h at the start of imbibition. Seeds imbibed first in water show reduced germination when subsequently transferred to nitrite. Dehulled seeds show little or no response to nitrate and ammonium ions.Intact seeds remain dormant in the presence of nitrite or nitrate unless partially dry-afterripened. The pH dependence of nitrite sensitivity is reduced in intact, afterripening seeds. In highly dormant seeds, vacuum infiltration experiments suggest that the hull restricts uptake of nitrite.

Journal Article↗
PubMed1983

Hypnotics and the control of breathing: a review.

Hypnotics are central depressants. In sufficient doses, they suppress respiration, and so their effects on respiration are important considerations in their safety. The paper reviews mechanisms of respiratory control and methods of assessment, the effects of hypnotics on control of breathing and new methods of non-invasive respiratory monitoring.

Anti-Anxiety Agents↗
PubMed1983

Noninvasive treatment of pneumothorax with oxygen inhalation.

The treatment for pneumothorax varies from invasive chest tube drainage to conservative management with bed rest. Based on the behavior of gases in closed body cavities, the inhalation of supplemental oxygen hastens absorption of the pneumothorax. To evaluate oxygen as a therapeutic agent, we treated 8 patients with pneumothoraces of various degrees with a high concentration of inspired oxygen delivered by a partial rebreathing mask. Periodic roentgenograms were used to measure the change in size of pneumothorax in order to assess the rate of resolution. 6 patients with pneumothoraces of less than 30% showed a mean resolution rate of 4.2% per day with reduction to one-third original size in the first 72 h. This was more than three times the rate of resolution (1.25% per day) previously reported with breathing room air alone. In 2 patients who initially received a lower concentration of inspired oxygen via nasal cannula, the rate of absorption increased after placing them on a partial rebreathing mask. 2 patients with four episodes of pneumothoraces greater than 30% did not benefit from this form of therapy and eventually needed chest tube drainage. We conclude that the administration of high concentrations of inspired oxygen is an effective method to enhance the rate of resolution of pneumothoraces, particularly when smaller than 30%, thereby reducing morbidity and duration of hospitalization and avoiding invasive drainage procedures.

Absorption↗
PubMed1983

Breathing abnormalities during sleep.

The purpose of this communication is to review obstructive and central breathing abnormalities that may occur during sleep, such as obstructive sleep apnea, and Cheyne-Stokes respiration. Emphasis is placed on noninvasive monitoring of the breathing pattern and intrapleural pressure swings by respiratory and surface inductive plethysmography, respectively, which establish the diagnosis of these abnormal breathing patterns.

Aminophylline↗
PubMed1982

Increased severity of obstructive sleep apnea after bedtime alcohol ingestion: diagnostic potential and proposed mechanism of action.

To assess the effect of 3 oz of 80-proof alcohol on the frequency and severity of obstructive sleep apnea (OSA), we studied six OSA patients and six healthy subjects on 2 nights. During the 1st night, when no alcohol was given, five patients demonstrated mild and one severe OSA episodes associated with a decline in arterial oxygen saturation to at least 92% (hypoxic event). On the 2nd night after ingesting 3 oz of alcohol just prior to bedtime, all the patients demonstrated a significant increase in the number and/or severity of hypoxic events compared with the no-alcohol night. Furthermore, the most severe hypoxic events occurred within 80 to 160 min after sleep onset, a significantly shorter latency after sleep onset than on the no-alcohol night. In contrast, the healthy subjects had no incidents of hypoxic events or breathing abnormalities during sleep after ingesting 0.8 gm/kg of alcohol. Possible mechanisms for these results are discussed. An OSA provocation test using alcohol is proposed during a 2nd night of evaluation for patients with mild to moderate or intermittent OSA conditions, but not for patients demonstrating severe hypoxic events or with alcohol intolerance. The alcohol provocation test would serve to determine the influence of alcohol on the frequency and severity of hypoxic events, providing the patient with a measure of the adverse effects of social drinking on their condition.

Adult↗
PubMed1982

Validation of respiratory inductive plethysmography using different calibration procedures.

We devised a new calibration procedure [least squares method (LSQ)] for respiratory inductive plethysmography (RIP) and compared it with our previously reported simultaneous equation method (SEQ) of analyzing data in 2 body positions and with the method of Stagg and associates using the analysis of individual breaths in a single body position. The values from RIP were compared with simultaneous spirometry (SP) in 20 normal subjects placed in the standing (STD), supine (SUP), sitting, prone, semi-recumbent, right lateral decubitus, and left lateral decubitus postures. The LSQ gave the most accurate results followed closely by SEQ. In addition, LSQ was compared with the isovolume angle maneuver (ISV) calibration procedure in supine (ISV-SUP) and standing (ISV-STD) postures. Each of the 10 normal subjects breathed at tidal volumes of 250, 750, and 1,250 ml in the SUP and STD postures. Of the values obtained by the LSQ method, 93% were within +/- 10% of SP in SUP and STD positions. Without a change in the posture in which the calibration was made, 83% of values with ISV-SUP and 90% of values with ISV-STD were within +/- 10% of SP. When body position was changed, 65% of the values obtained with ISV-SUP and 38% of the values obtained with ISV-STD were within +/- 10% of SP. With the LSQ, 45% of isovolume angles in SUP and STD position were within 45 +/- 3 degrees; 40% of isovolume angles with ISV-SUP and 60% with ISV-STD were within 45 +/- 3 degrees when body position was changed from position calibrated. In estimating fractional contribution of rib cage and abdominal compartments. LSQ was comparable to ISV in the standing posture but generally gave lesser values for the rib cage contribution in the supine posture than ISV. The optimal calibration procedure for respiratory inductive plethysmography in terms of accuracy and ease of subject performance is the least squares calibration procedure.

Calibration↗
PubMed1978

Sleep apnea.

Explore the source record for details and available documents.

Airway Obstruction↗
PubMed1978

Mucociliary transport in allergic patients with antigen-induced bronchospasm.

Tracheal mucous velocity (TMV) and respiratory mechanics were measured in asymptomatic asthmatic patients with ragweed hypersensitivity before and after inhalation of specific antigen, and with or without cromolyn sodium pretreatment. TMV was measured radiographically, and the airway response to bronchial provocation was monitored by measurements of forced expiratory volume in one sec and specific airway conductance. TMV was significantly less (6.3 +/- 2.3 mm per min, mean +/- SD) in the 6 asymptomatic asthmatic patients than in 7 normal subjects (11.6 +/- 3.6 mm per min, mean +/- SD). In the asthmatic patients, mean TMV diminished to 72 per cent of baseline immediately after bronchial provocation when specific airway conductance was decreased to 65 per cent of baseline or less, with a further decrease in TMV to 47 per cent of baseline after one hour, at which time respiratory mechanics had returned to baseline values. Pretreatment with cromolyn sodium prevented the decrease in TMV after bronchial provocation. We concluded that in asymptomatic patients with allergic asthma, (1) baseline TMV is impaired, (2) inhalation of specific antigen causes a marked decrease in TMV independent of the degree of bronchospasm, and (3) the decrease in TMV may be related to the release of chemical mediators.

Adolescent↗
PubMed1978

Failure of hypoxic pulmonary vasoconstriction in the canine asthma model. Effect of prostaglandin inhibitors.

Measurements of respiratory mechanics, arterial blood gases, and pulmonary vascular resistance were made before and 15 min after inhalation challenge with Ascaris suum extract in dogs with natural sensitivity to this antigen. 25 of 47 dogs were treated before inhalation challenge with a prostaglandin inhibitor (90 mg/kg of aspirin or 2 mg/kg of indomethacin by intravenous infusion). In response to the challenge, bronchospasm developed in approximately half (responders) of each group reflected by decreases in mean specific respiratory system conductance and arterial oxygen tension. While the dogs were breathing room air, pulmonary vascular resistance remained unchanged after antigen challenge in the responders not given aspirin or indomethacin, but increased significantly and was associated with a lesser degree of arterial hypoxemia in the responders pretreated with either of the prostaglandin inhibitors. Prevention of arterial hypoxemia by oxygen breathing blocked an increase in pulmonary vascular resistance in four pretreated responders. No changes in respiratory mechanics, pulmonary hemodynamics, or arterial blood gases were noted in the 21 dogs who did not develop bronchospasm regardless of whether or not they were pretreated. 12 additional dogs in whom arterial hypoxemia was produced by 10% oxygen breathing, showed an increase in pulmonary vascular resistance that was not potentiated by pretreatment with aspirin in 6. We conclude that in acute experimental canine asthma, vasodilator prostaglandins appear to blunt the hypoxic pulmonary vasoconstrictor response, thereby further compromising gas exchange but preventing the development of pulmonary hypertension.

Animals↗
PubMedDate not supplied

Effects of estazolam and flurazepam on cardiopulmonary function in patients with chronic obstructive pulmonary disease.

Benzodiazepine drugs have been shown to suppress respiratory function in patients with chronic obstructive pulmonary disease (COPD). We designed a placebo-controlled crossover study to compare the effects of a new benzodiazepine, estazolam ('ProSom'), with those of flurazepam ('Dalmane') on cardiopulmonary function in COPD patients. 29 patients completed all treatment phases (estazolam 2 mg, flurazepam 30 mg or placebo). Respiratory and cardiovascular function were assessed in awake patients on days 1 and 5 (acute and cumulative effects). Eight patients were also assessed during sleep in each period. The effects of estazolam and flurazepam on ventilatory response to CO2 and mouth occlusion pressure were no different from those of placebo. However, acute administration of flurazepam lowered tidal volume and increased inspiratory flow. Although no clinical signs of respiratory depression were observed with any long term treatment, flurazepam decreased oxygen saturation and inspiratory time and increased respiratory frequency. Neither drug altered breathing control during sleep. Our results indicate that estazolam 2 mg is equally as safe a hypnotic agent as flurazepam for patients with mild COPD.

Estazolam↗