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Biomedical subjects

B Olsson

Publications and source records attributed to B Olsson.

At least 145 records · Page 8Linked to original sources
PubMed1977

Training of spatial orientation with a senile demented patient. An experimental case study.

An 82 year old man, with the diagnosis senile dementia, was trained to find his own way to objects of importance on the ward (bed - toilet, dinner table - bed, dayroom - dinner table). The ward distances were divided into smaller units. A single case experimental design was used. During baseline the patient was given the opportunity to walk the distance. As long as he succeeded in finding the final destination, the distance was gradually extended one unit at a time. After one week each unit of the first distance was marked with a distinctive symbol and instructions were provided on their meaning. The two other distances served as control distances under baseline condition. One week later the second distance was also included in the intervention, while the third remained at baseline. Finally all distances were included in the intervention. There was a significant improvement in two of the three distances. This improvement was, however, only temporary.

Activities of Daily Living↗
PubMed1976

Stopped-flow spectrophotometric characterization of enzymic reaction intermediates in the anaerobic reduction of pig-plasma benzylamine oxidase by amine substrates.

Reduction of benzylamine oxidase by p-methoxybenzylamine under anaerobic conditions leads to biphasic absorbance changes at 470 nm. These reflect the intermediate formation of an enzyme substrate complex with spectral properties different from those of native enzyme and fully reduced enzyme. The spectrally modified enzyme-substrate complex exhibits a broad difference absorption band centered around 360 nm. The transient accumulation of this intermediate during reaction can be conveniently followed by stopped-flow techniques at wavelengths between 320 and 360 nm, where contributions from the subsequent reduction of the enzymic 470-nm chromophore are of minor significance. 2. Analogous intermediates exhibiting similar absorption spectra seem to be formed on reduction of the enzyme by benzylamine and other amine substrates which were tested. Substitution of benzylamine as the reducing substrate by [alpha, alpha-2H]benzylamine results in a decreased accumulation of the spectrally modified intermediate. This indicates that its formation is preceded by deprotonation of the alpha-carbon of the amine substrate. 3. Circular dichroism spectra of benzylamine oxidase exhibit a positive band at 360 nm, lending support to the previous conclusion that benzylamine oxidase is a pyridoxal enzyme. Formation of the spectrally modified enzyme-substrate complex then most likely reflects the prototropic shift converting an amine-pyridoxal Schiff-base obtained by rapid pre-equilibration between enzyme and substrate into an aldehyde-pyridoxamine Schiff-base.

Amines↗
PubMed1976

Some properties of coagulase-negative deoxyribonuclease-producing strains of staphylococci from human infections.

Twenty-seven coagulase-negative and deoxyribonuclease-positive staphylococci were isolated from more than 3000 specimens from human infections. The strains were tested by conventional biochemical tests and by simple agar plate assays for production of different extracellular enzymes and toxins. Three strains were lysed by S. epidermidis phages and 7 strains by S. aureus phages. All strains produced thermolabile nuclease but only 21 strains produced thermostable nuclease. The investigated strains belonged to a heterogeneous intermediate group sharing characters of S. aureus and S. epidermidis. Tests for production of coagulase and thermostable nuclease should be used in the classification of these intermediate strains in diagnostic bacteriology.

Bacteriophage Typing↗
PubMed1976

Effect of pH on the transient reduction of pig-plasma benzylamine oxidase by benzylamine derivatives.

1. The transient kinetics of reduction of the 470-nm absorption band in benzylamine oxidase by substrate at different pH values between 6 and 10 have been studied by stopped-flow techniques, and substituent effects on kinetic parameters for the reduction process have been examined using a series of ring-substituted benzylamine derivatives as the substrates. 2. Reduction of the enzyme by substrate takes place in two kinetically distinguishable steps, with the intermediate formation of an enzyme-substrate complex in which the substrate appears to be covalently bound through its amino group to the prosthetic group of the enzyme, possibly in the form of an amine-pyridoxal Schiff-base. 3. The apparent stability of the enzyme-substrate complex shows no obvious dependence on the electronic properties of the amine substrates, but is strongly pH-dependent in a way suggesting that substrate-binding involves the non-protonated amines, exclusively, and requires the presence of the acid form of an ionizing group in the enzyme with apparent pKa of 8.8. 4. Reduction of the enzymatic 470-nm chromophore and release of the aldehyde product of the catalytic process are rate-limited by the same monomolecular reaction step involving the enzyme-substrate complex. Rate constants for the rate-limiting reaction exhibit no significant dependence on pH between 6 and 10, but correlate with Hammett sigma-values for the ring-substituted benzylamine derivatives tested, yielding a phi-value of + 0.3.

Amines↗
PubMed1976

Kinetic isotope effects on the catalytic activity of pig-plasma benzylamine oxidase.

1. Isotope effects on the catalytic activity of benzylamine oxidase at pH 7 and 9 have been studied by steady-state and transient-state kinetics methods, using [alpha,alpha-2H]benzylamine as the substrate. 2. Replacement of the alpha-hydrogen atoms in benzylamine by deuterium has no significant effect on substrate-binding to benzylamine oxidase, neither does it affect the rate of reoxidation of the reduced form of the enzyme. Conversion of the primarily formed enzyme-substrate complex into the reduced enzyme species, however, exhibits an isotope effect of about 3. 3. The data obtained are consistent with a mechanism in which reduction of benzylamine oxidase takes place by a rapid pre-equilibration between enzyme and substrate to form an amine-pyridoxal Schiff-base, which is then tautomerized by a comparatively slow prototropic shift to an amino aldehyde-pyridoxamine Schiff-base from which there is a rapid hydrolytic release of the aldehyde product corresponding to the amine substrate. Proton abstraction from the alpha-carbon of the amine moiety in the primary Schiff-base appears to be at least partially rate-limiting for the tautomerization step, and hence for the entire process of enzyme reduction.

Animals↗
PubMed1976

Right atrial monophasic action potential and effective refractory periods in relation to physical training and maximal heart rate.

The monophasic action potential (MAP) and the effective refractory period (ERP) of the right atrium were determined in eight healthy volunteers before and after hard physical training. The duration and amplitude of the MAP increased in seven individuals after training. ERP showed no consistent changes. One possible explanation of the findings is an accumulation of intracellular potassium. The duration of the MAP was well correlated to maximal heart rate.

Action Potentials↗
PubMed1976

Formation of beta-lactamase in Bacteroides fragilis: cell-bound and extracellular activity.

Nine strains of Bacteroides fragilis were cultivated in stirred fermentors and tested for their ability to produce beta-lactamase. There was a correlation between formation of beta-lactamase and high values of the minimal inhibitory concentration against beta-lactam antibiotics. B. fragilis strain B70 was used for optimizing the production of beta-lactamase. The highest bacterial yield was obtained in a proteose peptone-yeast extract medium. Optimal conditions for growth and beta-lactamase production were obtained at 37 C and pH 7.0. The beta-lactamase was released into the surrounding medium during the growth period to about 50%. Osmotic shock released about 20% of the total activity, and remaining activity was found in the cytoplasmic fraction. Substrate profile studies on four beta-lactamase-producing strains showed that the enzymes were mainly cephalosporinases. They are inhibited by cloxacillin, p-chloromercuribenzoate, and iodine. Analytical isoelectric focusing in polyacrylamide gel gave an isoelectric point of 4.9 +/- 0.2 for three of the strains and 5.6 +/- 0.2 for one. Comparison with beta-lactamases from aerobic gram-negative species with regard to isoelectric points showed no similarities. Also the molecular weight of the beta-lactamase from strain B70 of 43,000 indicates that this is a new class of beta-lactamase.

Bacteroides fragilis↗
PubMed1976

Antibacterial susceptibility testing by the dip-slide technique: a methodological evaluation.

Antibacterial susceptibility testing of urine specimens by the dip-slide method was compared to the standardized disc diffusion method. A boarder line of 12 mm inhibition zone on the slide could be used to select strains resistant to sulphisadimidine, ampicillin, nitrofurantoin or nalidixic acid. In the case of the sulphonamide, the results were grewtly influenced by composition of the medium. Susceptibility testing with the dip-slide method seems to be a useful test to differentiate strains likely to respond to therapy from resistant strains.

Ampicillin↗
PubMed1975

Electrophysiological effects of the antiarrhythmic agent QX-572 in the human heart with special reference to rate-induced changes in effective refractory periods.

The antiarrhythmic agent, N,N-bis(phenylcarbamoylmethyl)dimethylammonium chloride (QX-572) 8 mg/kg body weight produced a decreased conduction time through the atrioventricular node but did not influence intra-atrial or intraventricular conduction. Effective refractory periods of the atrium, the atrioventricular conduction system, and the ventricle were shortened by the drug. The observed effects were present at the end of drug infusion but had disapnerbd 30 min later. The probable explanation is an increased sympathetic tone induced by QX-572.

Adult↗
PubMed1975

Soft tissue radiography in painful shoulder.

Specialized soft tissue radiography was applied to the shoulder region to differentiate between shoulder peritendinitis and radiating cervical pain. The technique is presented, together with the results of a clinical trial. Local inflammation was demonstrable even in the absence of calcific deposits.

Adipose Tissue↗
PubMed1975

Soft tissue xeroradiography of the shoulder joint.

Soft tissue xeroradiography of the shoulder joint has been compared with a film technique arrived at previously. The xerox plates gave a lower radiation dose to the patient without loss of information. The film technique requires a tungsten target tube with an extra thin glass window (=0.5 mm Al), while the xerox technique may be used with standard tubes.

Humans↗
PubMed1975

Antibiotic susceptibility testing of anaerobic bacteria by the standardized disc diffusion method with special reference to bacteroides fragilis.

The susceptibility of 90 strains of Bacteroides fragilis to 16 antibacterial drugs was determined by the agar plate dilution test and the disc diffusion test. Good correlation of results was obtained with the two methods, and regression line analysis could be performed for beta-lactam antibiotics, erythromycin, tetracyclines, lincomycin and clindamycin. Thus the standardized disc diffusion method can be used for susceptibility testing, but only a clear distinction between sensitive and resistant strains can be seen.

Agar↗
PubMed1975

Regression line analysis for five antibiotics with strains of Clostridium species.

The susceptibility of 90 strains of clostridia to 5 antibacterials was determined by the agar plate dilution method and the disc diffusion test. The correlations between minimum inhibitory concentration and inhibition zone were quite acceptable for lincomycin, clindamycin, tetracycline and doxycycline to calculate regression lines by the least square method. The strains showed comparatively wide ranges of susceptibility. For erythromycin, no regression line could be calculated, since all the strains tested were susceptible over a narrow range of concentrations.

Anti-Bacterial Agents↗
PubMed1975

[Fertility and fertility problems in some beef herds in Sweden (author's transl)].

The purpose of the study was to investigate the fertility level, some factors affecting fertility and problems of infertility in selected Swedish beef herds. The investigation included 31 herds, 19 of which had Herefords, 13 Charolais, 2 Aberdeen Angus and 1 Limousins. The total number of mature females was 703, including 147 feifers of breeding age. Most data were collected at personal visits to the herds. The results are presented in Tables I--XV and Figures 1--2. The service period coincided roughly with the grazing period and lasted usually 4--5 months. Seventyfive per cent of the females calved during the period February-May. The fertility levels were comparatively good. The percentage of pregnancy at rectal examination performed at the end of the service period was 89.5; however the average calving percentage was only 87.5. The highest calving percentages were recorded for Aberdeen Angus and crossbreds. Also the calf crop, it is the number of calves born alive and surviving 24 hours per mature female was the highest for these two groups; 0.91 and 0.90 respectively. The mean interval from calving to conception was 80.3 days in Herefords, 83.4 days in Aberdeen Angus, 85.6 days in crossbreds and 92.3 days in Charolais. The percentage of animals pregnant within 90 days after calving was on an average slightly more than 50 per cent. The interval from calving to conception rose gradually when the interval from calving to expoure to bull exceeded 40 days. Mean percentages of still born calves were 5.9 in cows and 13.7 in heifers. As far as the fertility level is concerned there does not seem to be any disadvantage in keeping the bull together with the females during the calving period. However, in this case the next calvings will occur over an extended period of time. If the intention is to concentrate 50 per cent of the calvings within the period of one month then the females should be exposed to the bull from 41--60 days after calving at the earliest. In case the females were exposed to the bull from 41--60 days after calving and onwards, 95 per cent of the females finally pregnant had conceived at the end of a 3 months service period. Under such conditions a bull may be able to serve two groups of females within the same grazing period. Cows calving during July-September had the lowest pregnancy rate and those calving during October-December the highest at the following service period. The incidence of ovarian cysts was very low. About 1/3 of those buls serving at least 10 females each obtained calving percentages less than or equal to 80. Herds recording low calving percentages had to a great extent used young bulls, 12--15 months of age at the beginning of the service period. Only for two groups of females out of eleven which had been served by young bulls calving percentages greater than 80 were noted. A more efficient control of the fertility of the bulls could markedly improve the fertility of some herds.

Abortion, Veterinary↗