Search PubMed⌕ Search

Biomedical subjects

M Meyer

Publications and source records attributed to M Meyer.

At least 649 records · Page 36Linked to original sources
PubMed1980

Solubility of inert gases in dog blood and skeletal muscle.

Solubility of H2, Ar, CH4 and SF6 was determined at 310 K (37 degrees C) in water, in saline (0.154 mol NaCl/l H2O), in plasma and whole blood of dogs, and in homogenates of the dog gastrocnemius muscle. The liquids were equilibrated with pure gases, and the dissolved gases were extracted and measured by gas chromatography as described previously (Meyer, M.: Pflügers Arch. 375, 161--165, 1978). In saline, the solubilities were 4% (SF6) to 15% (Ar) lower than in water. For dog blood the following mean values for the solubility coefficient (in mumol . 1(-1) . kPa-1) were found: for H2, 6.44; for Ar, 9.94; for CH4, 11.44; for SF6, 2.62. The red cell/plasma and the muscle/blood solubility ratios were near unity for H2, Ar and CH4 (ranging from 0.9 to 1.3); for SF6, however, they were much higher (about 2.1), apparently due to the high solubility of SF6 in hydrophobic substances (lipids).

Animals↗
PubMed1980

Alveolar-capillary equilibration kinetics of 13CO2 in human lungs studied by rebreathing.

Blood/gas equilibration of CO2 in lungs was studied in man by a rebreathing technique, in which the rate of uptake of the stable isotope 13CO2 in low concentration (inspired concentration about 0.07%) was measured at blood/gas equilibrium of the abundant CO2 isotope. The results were expressed in terms of overall conductance for alveolar gas-pulmonary blood equilibration (DCO2, pulmonary diffusing capacity for CO2). The following mean values of DCO2 were found in 3 healthy young men (in mmol . min-1 . Torr-1): rest, 8.0; during exercise (75 Watts), 13.7. Comparison with DO2 measured by rebreathing in the same conditions suggests equilibration of the CO2/HCO3(-)/H+ system in blood, rather than diffusion of CO2, as the limiting process in capillary/alveolar CO2 transfer. The term 'equilibration capacity' is thus suggested for DCO2. Calculations based on the experimental results show that the overall limitation of pulmonary CO2 exchange function resulting from this finite DCO2 is slight at rest, but of considerable extent in heavy exercise.

Carbon Dioxide↗
PubMed1980

Single-exhalation method for study of lobar and segmental lung function by mass spectrometry in man.

A single-exhalation method, based on a modification of the conventional single-breath technique, was applied to study lung function in normal subjects during fiberoptic bronchoscopy. After a single inspiration of a test gas mixture (1% He, 1% C2H2, 0.07% C18O in air), the test gas concentrations were continuously monitored during subsequent slow exhalation, using a respiratory mass spectrometer that sampled either at the lips (Whole-lung test) or, through the bronchoscope, at various sites within the bronchial tree (Regional test). Changes in concentrations of the test gases with time allowed estimation of alveolar ventilation (Va), blood flow (Q), and diffusing capacity (DLCO), per unit accessible lung volume (Va). In the Whole-lung test, both DLCO and Q agreed closely with values obtained in the same subject by a rebreathing method. No differences were observed between the upright and the lateral decubitus positions. In teh Regional test, VA/VA, DLCO/VA and Q/VA were larger in the dependent than in the upper lung, when sampling was from the main bronchi in the lateral decubitus positions. Sampling from lobar bronchi in the upright position revealed an increase from top to bottom in VA/VA, DLCO/CA and Q/VA, this being most marked for Q. These results are compatible with the regional variations that have been shown by radioactive techniques and have been attributed to gravitational forces. The method appears to be suitable for the study of lobar and segmental lung function in patients with lung disease.

Bronchoscopy↗
PubMed1980

Correlation between size and age at different events in the cell division cycle of Escherichia coli.

The variability of (i) the B period between birth and initiation of chromosome replication, (ii) the U period between initiation of chromosome replication and initiation of cell constriction, and (iii) the interdivision period (tau) have been estimated for slowly growing Escherichia coli B/r F. Cultures synchronized by the membrane elution technique were pulse-labeled with [3H]thymidine or continuously labeled with [3H]thymine. After fixation, the pattern of deoxyribonucleic acid replication was analyzed by electron microscopic radioautography. Cell length was found to increase exponentially with age at two different slow growth rates. The coefficient of variation of the B period was estimated to be 60%, that of the U period was 29%, and that of the interdivision period was 12%. From these values and the coefficient of variation of length at different cell cycle events were calculated a negative correlation between the B and U period (r = -0.9) and a positive correlation between length at birth and cell separation (r = 0.6). Initiation of chromosome replication and cell constriction were strictly correlated both with respect to age (r = 0.7) and length (r = 0.8). On the other hand, length at initiation of chromosome replication was distantly correlated with age (r = 0.1) or length at birth (r = 0.3). This low correlation excludes a model in which chromosome initiation is controlled by a random event in the B period. It favors a model in which chromosome initiation occurs at a particular distributed size independent of cell division.

Cell Cycle↗
PubMed1980

Solubility of acetylene in human blood determined by mass spectrometry.

To measure the acetylene solubility (alpha C2H2) in human blood, a blood sample, which had been equilibrated with a gas mixture containing C2H2, was injected into an airtight acetylene-free vessel, and the gas partial pressure was measured by mass spectrometry after reequilibration. The system was calibrated by injecting into the vessel a known volume of the equilibrating gas mixture. At 37 degrees C, alpha C2H2 averaged 0.768 +/- 0.004 (SD) ml STPD.ml blood-1.atm-1, which is only slightly above the data from the literature.

Acetylene↗
PubMed1980

Application of bromhexine metabolite VIII (NA 872) and bromhexine-glucose in treatment of adult respiratory distress syndrome; experimental and clinical results .

The authors study the changes in cardiopulmonary function after application of bromhexine metabolite VIII (NA 872) in an animal model of adult respiratory distress syndrome (ARDS) and bromhexine glucose solution (BGS) in ARDS patients. After damage of the lung alveolar surfactant by intratracheal atomization of 0.2 M HCl in LEWE Minipigs significant changes in lung compliance, dead space ventilation, venous admixture, alveolo-arterial oxygen tension difference, pulmonary vascular resistance, and oxygen uptake are present under application of NA 872 in comparison to untreated animals. In ARDS patients treated with BGS, pulmonary function is significantly ameliorated indicated by changes in static effective compliance, oxygen exchange ratio, and alveolo-arterial oxygen tension difference.

Animals↗
PubMed1980

[Lymphocytic infiltrations of the nipple. The benign cutaneous lymphocytoma of the breast areola (author's transl)].

Benign lymphocytic infiltrations may often occur in the skin of nipple and areola: 55 cases have been described in literature especially in Scandinavia and in Germany, sometimes in correlation with tick bites or erythema chronicum migrans, but until now no cases have been reported in France. In a retrospective study of 30 cutaneous lymphocytomas, we found 8 cases localized on the breast-3 children and 5 older patients-, associated with a erythema chronicum migrans in 3 patients and following a tick bite in another patient. The course of the disease is always benign and the healing can be accelerated by penicillin therapy. The pathogenesis still remains unclear but some data argue for an infectious mechanism: frequency of tick bites (20 p. 10), geographical occurrence in the spreading area of common ticks in Europe, affinity of ticks for the breast in all mammals, carriage of viruses by some tick species, efficiency of penicillin in tick-transmitted viral infectious and in benign skin lymphocytomas, positive inoculations in volunteers, general course of an infectious disease (seasonal variations, frequency of satellite lymph-node swelling, spontaneous healing).

Aged↗
PubMed1980

[Therapy of salmonella enteritis with special reference to lactulose (author's transl)].

Excretion of Salmonellae in two groups of outpatients with Salmonellae is discussed. In one group of 51 adults, a total of 30 different serotypes were isolated. These patients were treated with lactulose and after four weeks the organisms had been eliminated in 68.6%. In a group of 23 adults receiving no treatment whatsoever, 56.5% were still excreting the organism after four weeks. Of the 64 in-patients studied, 37 received various antibiotics, 14 lactulose and in 13 only the symptoms were treated. The length of the excretion period was longer for the group receiving antibiotics (four weeks after onset of illness 67.8% were still excreting the organism). Treatment with lactulose, however, resulted in a shorter period of excretion for these patients. Special aspects of the various groups - e.g. age structure, pattern of infecting organisms - are reported in detail.

Adult↗
PubMed1980

Solubility of helium, argon, and sulfur hexafluoride in human blood measured by mass spectrometry.

A method has been developed to measure the solubility coefficients of gases in liquids by respiratory mass spectrometry. A sample (2.5 ml) pf the test liquid, equilibrated with a test gas mixture, is injected into a sealed flask (approximately 140 ml) for extraction by equilibration. The reequilibrated gas phase in the flask is analyzed by a mass spectrometer. Separately, an equal volume (2.5 ml) of the equilibrating test gas mixture is injected into a larger sealed flask (approximately ll liter) where it is mixed and then analyzed by the mass spectrometer. Solubility in the liquid is calculated from the ratio of mass spectrometer readings in both flasks and the ratio of flask volumes. The ratio of volumes of the small and the large flasks is made similar to the gas/liquid partition coefficient whereby the mass spectrometer readings in both become similar. With this approach, errors due to amplifier and mass spectrometer nonlinearity are greatly attenuated. The method was used to measure the solubility of helium, argon, and sulfur hexafluoride in distilled water, human plasma, and human blood.

Argon↗
PubMed1979

Gas exchange in the parabronchial lung of birds: experiments in unidirectionally ventilated ducks.

Pulmonary exchange of O2 and CO2 was measured in unidirectionally ventilated ducks in an attempt to determine lung O2 diffusing capacity, DO2. Perfusion shunt (= venous admixture) was estimated from O2 exchange in hyperoxia, and the ventilation shunt (ventilation of non-perfused parallel lung units) was estimated from exchange of the highly soluble inert gas, chloroform. Differences in the ventilation/perfusion ratio of parallel lung units were assessed from measurement of CO2 exchange using a parallel two-compartment model. DO2 values were calculated accounting for ventilation shunt, perfusion shunt, and inhomogeneity. Perfusion shunt averaged 2.7% and ventilation shunt, 9.4%. The ventilation/perfusion ratio in the two compartments differed on the average by a factor of 2.6. The uncorrected values of DO2, not accounting for lung inhomogeneities, progressively declined with increasing inspired PO2, but this dependence was less pronounced after correcting for lung inhomogeneities. The corrected value of DO2 averaged 100 mumol . min-1 . torr-1 for ducks of 1.8 kg mean body weight. DO2 did not differ when nitrogen was replaced by helium in the ventilatory gas indicating that diffusion within the air capillaries did not contribute a significant resistance to O2 uptake. The results suggest that neither functional inhomogeneities nor diffusion between lung gas and blood limit O2 uptake of the resting duck. Under conditions of elevated metabolism, however, these parameters may become rate-limiting for O2 supply.

Animals↗
PubMed1979

Gas exchange, pulmonary mechanics and haemodynamics in adult respiratory distress syndrome: experimental results in Lewe miniature pigs.

Adult respiratory distress syndrome (ARDS) is a common medical emergency in respiratory care complicating a great variety of traumas and diseases. An animal model from Lewe miniature pigs has been developed to study the ARDS under standardized conditions; it is based on aspiration pneumonitis, a disorder often observed in ARDS, injuring the lung alveolar surfactant system. The experimental study was conducted under neuroleptanalgesia. ARDS was produced by intratracheal application of hydrochloric acid (0.2 mol/l) in an amount of 1.0 ml/kg body wt. The animals were ventilated automatically by a standardized ventilatory pattern in IPP mode. In all animals the time course of oxygenation ratio (Pa,O2/F1O2), arterial CO2 tension (Pa,CO2), ratio of alveolo--arterial oxygen tension difference to inspired oxygen fraction (Aa,DO2/F1O2), oxygen exchange ratio ((AaDO2/Pa,O2), lung compliance (CL), inspiratory airway resistance (RrsI), dead space ratio VD/VT), pulmonary artery pressure (PAP) and systemic blood pressure were studied. Changes in quasi-static volume--pressure curves, percentage change in lung water content and gross pathological finding were used to integrate the findings into a system of pathophysiological changes in ARDS. The animal group to which hydrochloric acid was administered shows severe pulmonary distress leading to death within 3.5--7.5 h. No significant changes in the measured parameters could be observed in the control group over a 14 h period. The results suggest that aspiration pneumonitis in Lewe miniature pigs is very suitable to investigate various problems in pathogenesis of ARDS. The model provides reproducible results which correlate very well with findings in different ARDS states. The models serves both to compare clinical states and to search for newer therapeutic manoeuvres.

Animals↗