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Biomedical subjects

M Meyer

Publications and source records attributed to M Meyer.

At least 667 records · Page 37Linked to original sources
PubMed1979

Length growth of two Escherichia coli B/r substrains.

Length growth of synchronized Escherichia coli B/r substrain A (ATCC 12407) and B/r substrain F26 (Thy his) was followed with an electron microscope. Cells were grown with doubling times (tau) of 60 min (B/rA) and of 82 and 165 min (B/rF26). Different length growth patterns were found for the two substrains. In B/rF, the length growth rate increased about midway in the cell cycle. For tau = 165 min, the rate increase was preceded by a short period of slow growth. For B/r A (r = 60 min), this period seemed to occur at the beginning of the cell cycle. The possibility is raised that the different length growth patterns are related to different deoxyribonucleic acid replication patterns of the respective strains.

Cell Cycle↗
PubMed1979

A broth-disc technique for the assay of antibiotic synergism.

A broth-disc technique has been developed to demonstrate the antibiotic synergism of some broad-spectrum penicillins plus an aminoglycoside against Pseudomonas aeruginosa and enterococci. Utilizing the zone sites obtained from Kirby-Bauer susceptibility tests, approximate minimum inhibitory concentrations of each antibiotic upon individual isolates were derived using standard regression curves. One-fourth of each value was calculated and the approximate desired concentration then prepared in Mueller-Hinton broth through use of the labelled antibiotic disc content. Tubes were inoculated with a standardized suspension of organism and incubated at 35 degrees C for 18-24 h. Subsequently, inhibitory end points were recorded. This approach to synergy testing showed good correlation with the standard checkerboard method. The broth-disc synergistic assay is also reproducible, financially feasible, and less time-consuming to execute.

Amikacin↗
PubMed1979

Arterial-expired PCO2 differences in the dog during acute hypercapnia.

A recent report (J. Appl. Physiol. 38: 382-388, 1975) suggests that negative blood-gas CO2 partial pressure (PCO2) differences exist in the dog during hypercapnia, as mean expired PCO2 exceeded arterial PCO2 by more than 10 Torr when the CO2 fraction in inspired gas (FICO2) was 0.1. We have reinvestigated this problem in anesthetized dogs breathing spontaneously room air or hypercapnic mixtures (FICO2 = 0.05 or 0.10). During steady state, arterial blood samples were analyzed with electrodes, care being taken to keep the electrode temperature within +/- 0.2 degrees C at the actual aortic temperature of the animal. Respired gas was measured at the tracheostomy by a sensitive low-noise respiratory mass spectrometer. During room air breathing, the arterial-end-expired PCO2 difference, P(a-E')CO2, averaged +5 Torr and decreased to +0.9 Torr and to +0.1 Torr with FICO2 = 0.05 and 0.1, respectively. Hypoxia (FIO2 = 0.10) had no apparent effect on the P(a-E')CO2 difference. We ascribe the decrease in P(a-E')CO2 with hypercapnia to the diminishing effects of alveolar dead space, whereby end expired PCO2 approached arterial PCO2. We then conclude that in blood-gas equilibration lungs, PCO2 in end-capillary blood comes close to alveolar PCO2, and that the negative blood-gas PCO2 differences reported earlier are probably caused by deficiencies in the techniques used.

Animals↗
PubMed1979

[Animal model of acute respiratory insufficiency by HCl aspiration in Lewe mini-pigs].

Acute respiratory insufficiency or adult respiratory distress syndrome is a common medical emergency in intensive medicine complicated by high mortality. To study the acute respiratory insufficiency under standardized conditions an animal model in Lewe-mini-pigs has been developed. This model is based on aspiration pneumonitis produced by intrabrochial atomisation of 0.2 N hydrochloric acid. General anesthesia was performed by neuroleptanalgesia. In all animals the profound changes in gas exchange, pulmonary mechanics and hemodynamics as well as quasi-static volume-pressure relationships after hydrochloric acid aspiration were described. The results suggest that this model is suitable to outline the profound changes in pulmonary function in this type of acute respiratory insufficiency.

Acute Disease↗
PubMed1978

Klinefelter syndrome and neurological disease.

Six patients with Klinefelter syndrome (47,XXY) and different neurological disease are described. Essential tremor has been reported repeatedly but its significance deserves further studies. The prevalence of epilepsy with the Klinefelter syndrome is higher in comparison with the normal poplation, but it is not greater than expected in the population of a mental hospital. Therefore we suggest that the neurological symptoms with the Klinefelter syndrome should basically be regarded as coincidental findings not related to the chromosome abnormality.

Adolescent↗
PubMed1978

Energetics of anaerobic glycolysis in dog gastrocnemius.

Thermally isolated gastrocnemii were stimulated to exhaustion, by rhythmic isotonic (70 N) tetanic contractions, during complete occlusion of blood flow. Enthalpy change (h = work + heat) and work output (w) (kJ/kg) were obtained from records of deep muscle temperature and shortening. The lactate produced (LA, mol/kg) was measured in the outflow after reestablishement of blood flow. The following relationships were obtained: h = 76LA + 1.2, and w = 19.8LA + 0.30. As the energy liberated at exhaustion by alactic energy sources (approximately P and O2 stores) is constant, deltah/deltaLA = 76 (+/- 10.5; S.E.) kJ/mol is the enthalpy change for lactate formation (delta HLA). The neutralization heat was estimated on muscle homogenates at 12kJ/mol, leaving approximately 64 kJ/MOL for deltaH of LA formation proper. The mechanical efficiencies of work related to LA formation (ELA) and of that not related to LA formation (EnonLA) were practically identical (0.25). From these values and from deltaHLA, the enthalpy change of approximately P splitting was estimated in the range of 52--62kJ/mol, depending on the value of the ratio delta approximately P/deltaLA assumed in the calculation.

Adenosine Triphosphate↗
PubMed1978

Bohr effect induced by CO2 and fixed acid at various levels of O2 saturation in duck blood.

The Bohr factor, phi = delta log Po2/deltapH, was determined at various levels of hemoglobin O2 saturation (SO2) in fresh whole blood of the duck. Plasma pH was varied by either changing PCO2 of the blood at constant base excess (CO2 Bohr factor, phiCO2) or by addition of NaHCO3 and HCl at constant PCO2 (fixed acid BOHR factor, phiAH). No differences were found between phiCO2 and phiAH at SO2 levels between 20 and 85%, and there was no saturation dependence of the Bohr factor, its average value being -0.44. It is concluded that in whole blood of this bird species CO2 exerts no direct effect on the O2 affinity of hemoglobin.

Animals↗
PubMed1978

Technique for measurement of inert gases in liquids by gas chromatography.

A method for quantitative analysis of inert gases in liquids by gas chromatography is described. The technique comprises an equilibration system for partial extraction of dissolved gases from liquids and a gas chromatograph equipped with helium ionization detector. The method is particularly devised for determination of solubility coefficients of gases in liquid materials, e.g. water, aqueous solutions, blood, tissue homogenates, and for simultaneous measurement of several inert gases dissolved in liquids. Coefficients of variation for serial analyses of individual samples were less than or equal to 3%. The method is applicable to studies of blood-tissue transfer of respiratory and inert gases.

Chromatography, Gas↗
PubMed1978

[Early diagnosis of cancer of the prostate by rectal palpation (author's transl)].

Transrectal biopsy was performed on 173 unselected patients, aged 45-85 years, with disease of the prostate, who had previously had a screening examination. The findings on palpation by the referring doctor and the authors' own assessment were compared with the histological findings. Of 37 histologically confirmed cases of carcinoma of the prostate 16 (44%) had been correctly diagnosed by the referring doctor and 28 (76%) after examination at hospital. On the other hand, of 136 histologically negative cases the referring doctor's diagnosis had been correct in 112 (81%) instances and at hospital 94 (69%).

Aged↗
PubMed1978

Mixing technique for study of oxygen-hemoglobin equilibrium: a critical evaluation.

In the mixing technique for study of oxygen-hemoglobin equilibrium, the O2 saturation (SO2) of a blood mixture is calculated from the volume ratio at which an oxygenated sample is mixed with a deoxygenated sample, and the PO2 in the mixture is measured polarographically. Any predetermined level of SO2 may be obtained by proper choice of the volume ratio. It is shown that the volume and oxygen saturation of the mixed samples are by far the most critical parameters in calculating SO2, and a method is suggested by which the volume ratio is accurately measured by weighing the blood samples before mixing. Other parameters that influence determination of SO2, e.g., the O2 capacity of the blood, are much less important. The method has been applied to establish the O2 dissociation curve in human blood, and good reproducibility and agreement with standard curves were obtained. Measurements in rabbit blood yielded similarly satisfactory results. The technique is particularly applicable to problems that require exact adjustment of SO2 to a predetermined value, such as determination of the half-saturation pressure or of the Bohr effect at various levels of O2 saturation.

Animals↗
PubMed1978

Electrical spinal cord stimulation for spastic movement disorders.

Spinal cord stimulation seems today a promising method to improve spasticity. The experiences of two different clinics (Zürich and Freiburg i.Br.) are reported with long-term assessment up to 28 months. The objective data with measurement of stretch and H reflexes support the clinical results. An experimental study on animals does not permit a definitive explanation, but some hypotheses can be suggested.

Adult↗
PubMed1978

A study of outpatient satisfaction with mental health center services.

In 1972 the authors conducted a study to determine the effect of encouraging patients to express their dissatisfaction with services received at a community mental health center in New York City. Half of the out-patients admitted to the center over a six-month period, a total of 270, were sent welcoming letters signed by the center director soliciting suggestions and complaints about services and listing staff members to whom they could be reported. Follow-up telephone interviews both with recipients of the letter and with nonrecipients, who formed a control group, showed that the recipients had fewer complaints about the center's services than did the nonrecipients. However, they failed to use the suggested channels to report a number of relatively serious complaints. The authors discuss the implications of the findings.

Adult↗