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Biomedical subjects

C Jordan

Publications and source records attributed to C Jordan.

At least 91 records · Page 5Linked to original sources
PubMed1981

Rapid improvement in abnormal pulmonary epithelial permeability after stopping cigarettes.

A new, non-invasive method of measuring pulmonary epithelial damage in man was compared with traditional tests of small-airway function. Pulmonary epithelial permeability was expressed as the half-time clearance from the lung into blood of (99m)Tc-diethylene triaminepenta-acetic acid ((99m)Tc-DTPA) deposited predominantly in the alveoli from an inhaled aerosol.Recovery from abnormal pulmonary permeability was recorded after stopping smoking for 21 days in a group of young symptomless cigarette smokers. Before stopping smoking there was a significant correlation between half-time lung clearance of (99m)Tc-DTPA and carboxyhaemoglobin concentration (r=0.69; p <0.05). There was no correlation between carboxyhaemoglobin value and closing volume, the only other abnormal test of airway function. Twenty-four hours after stopping smoking the mean half-time lung clearance of (99m)Tc-DTPA had increased significantly (p <0.001) from a baseline of 15.8 min (SEM 1.3 min) to 25.5 min (SEM 2.5 min). The mean half-time clearance continued to increase to a maximum of 35.5 min (SEM 3.1 min) at seven days, but was significantly less than the reported half-time clearance for non-smokers (59 min, SEM

Adolescent↗
PubMed1981

Alcohol induced discoordination is not reversed by naloxone.

It has previously been reported that prior administration of naloxone may prevent the decrement in performance produced by alcohol. To be clinical value, however, naloxone must be shown to reverse rather than prevent this decrement. This study examined the effect of naloxone given after consumption of alcohol. A double blind balanced crossover protocol was used to examine the effect of either 1.2 mg or 10 mg naloxone on the sensory-motor impairment produced by blood alcohol concentrations maintained between 75 and 85 mg/100 ml. This alcohol concentration significantly impaired two measures of sensory-motor performance, but there was no evidence that either dose of naloxone could reverse this decrement. We tested our subjects for a chlorpropamide alcohol flush but none gave a positive response. These results indicate that naloxone (1.2 mg or 10 mg) does not reverse the sensory-motor impairment produced by alcohol intoxication in subjects who do not exhibit a chlorpropamide alcohol flush. Nearly all the subjects exhibited somnolence after receiving alcohol and naloxone (1.2 mg or 10 mg) but not after receiving alcohol and saline.

Adult↗
PubMed1981

Specific conductance using forced airflow oscillation in mechanically ventilated human subjects.

A method is described to measure specific airway conductance in mechanically ventilated patients. Airflow resistance (R) was measured continuously using the forced airflow oscillation method and plotted against volume during slow deflation of the lungs. The previously reported hyperbolic configuration of the resistance-volume curve was confirmed, but a nonlinear conductance-volume relationship was found that could be explained by a constant resistance (A) in series with the volume-dependent resistance of the lower airways. A computer-aided analysis of the resistance-volume curve determined the parameters of the hyperbola that best fitted the data and from this the volume-dependent conductance, Glaw = 1/(R - A), was calculated. This method consistently provided a very good fit to the data and resulted in a linear lower airway conductance-volume relationship in anesthetized and in awake subjects. The slope of this linear relationship (Glaw) was therefore independent of volume, and specific lower airway conductance was used as an index of bronchomotor tone. In awake subjects given bronchoconstrictor and bronchodilator aerosols, good correlation was shown between changes in specific conductance measured by this technique and by the standard plethysmographic method.

Airway Resistance↗
PubMed1980

Respiratory effects of analgesia after cholecystectomy: comparison of continuous and intermittent papaveretum.

Two methods of administering papaveretum for relieving postoperative pain were compared in two groups of patients who had undergone cholecystectomy. In one group a loading dose of papaveretum was administered by continuous intravenous infusion (1 mg/min) until the patient could breathe deeply without undue pain. Eight times this loading dose was given as a continuous intravenous infusion over the subsequent 48 hours. This regimen was compared with a conventional intermittent intramuscular dose (0.25 mg/kg at four hourly intervals as necessary) in a second group of patients. The intravenous regimen relieved pain better than the intramuscular regimen, which may have reflected the larger dose of papaveretum given to the intravenous group, but it was accompanied by a greater degree of respiratory depression and potentially life-threatening changes in respiratory pattern. These findings suggest that the fear which often accounts for inadequate postoperative pain relief-that larger dose of analgesics will cause respiratory complications-is well founded.

Adult↗
PubMed1980

Respiratory depression following diazepam: reversal with high-dose naloxone.

The authors compared the effects of naloxone and saline solution on the respiratory changes following diazepam in a double-blind crossover trial in six subjects. Following baseline measurements of respiration, each subject was given diazepam, 15 mg, intravenously. Sixty and ninety-five minutes later each subject received either two doses of naloxone, 15 mg, intravenously, or two doses of the equivalent volume of saline solution. Forty-five minutes after diazepam administration the slopes of the curves of the ventilatory responses to rebreathing carbon dioxide (VE/PETCO2) were depressed to 53 per cent of control (P < 0.05). Following the two doses of naloxone, the slopes of VE/PETCO2 recovered, until, 120 minutes after the second dose of naloxone, slopes had returned to control values. After saline solution, however, slopes remained depressed at 68 per cent of control (P < 0.05). A similar recovery following naloxone was observed in the PETCO2 intercept of the VE/PETCO2 response curve and in the slope of the mouth-occlusion-pressure response curve to rebreathing carbon dioxide. End-tidal carbon dioxide during quiet breathing and during inspiratory resistive-loaded breathing (80 cm H2O/l/s) showed small increases after diazepam, which were not significantly reduced by naloxone. The results of this study show that diazepam produces respiratory depression, and that this may be relieved by large doses of naloxone.

Adult↗
PubMed1980

Normal audiometric findings.

We argue that the scope of basic audiometric assessment must be broadened to include speech audiometric measures sensitive to central auditory dysfunction. Findings in twenty cases of retrocochlear disorder illustrate the fact that conventional criteria of audiometric normalcy are inadequate.

Adolescent↗
PubMed1979

Bacillus cereus endogenous panophthalmitis.

A case of severe suppurative endogenous panophthalmitis caused by Bacillus cereus resulted from intravenously administered medications. This is the first, to our knowledge, well-documented case of endogenous endophthalmitis associated with this organism. It is recommended that if on Gram's stain of the anterior chamber fluid, Gram-positive rods are seen, chloramphenicol should be administered in addition to penicillin because of the possibility of B cereus infection.

Adult↗
PubMed1979

Measurement of the relative contributions of rib cage and abdomen/diaphragm to tidal breathing in man.

A simple mathematical model of the chest wall was constructed so that during tidal breathing the relative volume contributions of the rib cage and abdomen/diaphragm could be measured in man, using four mercury-in-rubber strain gauges around the trunk. From the dimensions of the trunk and the change in circumference determined by the four gauges, the separate contributions of rib cage and abdomen/diaphragm could be determined using a purpose-built analog computer. The system was evaluated in 13 laboratory personnel, and in 13 other subjects before and after anaesthesia. There was a linear relationship between tidal volumes computed and measured at the mouth, over the residual volume to (FRC + 1 litre) range, with an error of +/- 8%. The relative contribution of rib cage to tidal breathing showed a large scatter from 5 to 42% with a non-significant tendency to decrease with age.

Abdomen↗
PubMed1979

A comparison of the respiratory effects of meptazinol, pentazocine and morphine.

The respiratory effects of a new strong analgesic, meptazinol, were compared with a placebo and with equianalgesic doses of morphine and pentazocine in a double-blind crossover trial in seven healthy volunteers. No significant change in the ventilatory response to rebreathing carbon dioxide was observed after meptazinol 100 mg/70 kg or placebo. However, both morphine 10 mg/70 kg and pentazocine 60 mg/70 kg depresesd the slope of the ventilatory response (-30.0% and -31.6% respectively, P less than 0.02, averaged over the first 3.5-h period). End-tidal carbon dioxide tension (PE'CO2) while breathing room air increased significantly following all three drugs. However, the increase in PE'CO2 after meptazinol (0.22 kPa averaged over 3.5 h) was significantly less than that following morphine (0.40 kPa, P less than 0.05) and pentazocine (0.59 kPa, P less than 0.01). While breathing room air with a resistive inspiratory load of 8 kPa litre-1 s, PE'CO2 again increased significantly (P less than 0.05) following all three drugs. The increase in PE'CO2 after meptazinol was then the same as that after morphine (0.51 kPa averaged over 3.5 h). The increase following pentazocine (0.80 kPa) was significantly greater than that after both morphine and meptazinol (P less than 0.02).

Adult↗