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Biomedical subjects

B E Andersson

Publications and source records attributed to B E Andersson.

16 recordsLinked to original sources
PubMed2001

Three-dimensional outgrowth of a wood-rotting fungus added to a contaminated soil from a former gasworks site.

The capability of wood-rotting fungi (WRF) to colonise contaminated soil is an important fungal characteristic in the development of WRF-based soil bioremediation, it is also important to have methods that monitor the presence of the WRF in the soil. In this lab-scale study, it was shown that it was possible to re-capture, localise and identify a brown-rot fungus, Antrodia vaillantii, after it has been inoculated into, and grown in, a contaminated soil from a former gasworks site. The three-dimensional outgrowth of A. vaillantii was monitored by allowing it to grow into fungicide-treated wood baits, temporarily placed in the soil. After two weeks, the baits were withdrawn from the soil and surface sterilised with hydrogen peroxide to favour fungi growing inside baits, i.e., A. vaillantii. After subsequent plating of baits on selective agar medium the presence of A. vaillantii was confirmed with PCR/RFLP. A. vaillantii was found to be viable throughout the 54 days long study and exhibited a surface growth pattern similar to other well-known cord-forming basidiomycetes. Firstly, the upper part of the soil closest to the place of inoculation was colonised, however, over a period of time, the area of colonisation spread deeper into the soil. The detection method employed in the current study gave a conservative estimate of the fungal proliferation and did not require extensive sampling. Its use could be applicable in both applied research, such as soil bioremediation, and in pure microbial ecology studies.

Benomyl↗
PubMed2000

Degradation of acenaphthene, phenanthrene and pyrene in a packed-bed biofilm reactor.

Biofilm reactors are particularly suitable for the treatment of large amounts of diluted effluent, such as groundwater contaminated with scarcely soluble pollutants. A packed-bed column reactor was tested for the degradation of acenaphthene, phenanthrene and pyrene provided at their aqueous solubility concentrations. Acenapthene and phenanthrene were removed to more than 99% efficiency from this reactor whilst pyrene was removed to 90%. Pollutant disappearance was also recorded in the control reactor and was probably caused by the adsorption of pollutants into the reactor. The measurement of oxygen consumption in both reactors confirmed that microbial degradation of the pollutants was indeed occurring in the inoculated reactor. Physical adsorption is not however unwanted, as it could help with the formation of a biofilm at an early stage of the treatment.

Acenaphthenes↗
PubMed1995

Clinical electroretinography in the dog with ganzfeld stimulation: a practical method of examining rod and cone function.

We used a simple and reproducible technique with full-field electroretinography and a special-purpose computer system to test and evaluate outer retinal function in dogs. The standardized protocol included the following five basic responses: (1) a stable initial light-adapted, mainly cone derived response, (2) a dark-adapted rod response, (3) chromatically separated rod and cone responses, (4) a maximal rod and cone response and (5) an isolated cone flicker response. For evaluating the electroretinographic responses, a graphic-presentation was used that included data from the tested animal as well as normative data from dogs of the specific breed and age group, presented as the percentage of the median in which limits of normality were depicted in percentiles.

Adaptation, Ocular↗
PubMed1989

Effects of intravitreal perfusion with dopamine in different concentrations on the DC electroretinogram and the standing potential of the albino rabbit eye.

The direct current electroretinogram and the standing potential were recorded from both eyes of 23 albino rabbits during intraocular perfusion of one of the eyes, which was vitrectomized, with a physiologic reference solution (PHS). PHS was then replaced by a test solution containing dopamine dissolved in PHS. The fluids were subsequently alternated (PHS-dopamine-PHS). During irrigation with 0.25-0.5 mM dopamine (11 rabbits) the c-wave amplitude was 140% higher (p less than 0.001) and during irrigation with 25 mM dopamine (6 rabbits) 85% lower (p less than 0.01) than it was during the corresponding initial perfusion with PHS. The simultaneously recorded b-wave amplitude was reduced (0.25-0.5 mM: -22%, p less than 0.001; 25 mM: -69%, p less than 0.001) and the SP level increased (0.25-0.5 mM: +2375 microV, p less than 0.01; 25 mM: +2530 microV, p less than 0.05) compared with the values obtained during the corresponding preceding irrigation with PHS. Thus the changes in the b- and c-wave amplitudes during perfusion with dopamine were dependent on the concentration of the drug. In the contralateral control eye (23 rabbits) the c-wave amplitude was 21% higher (p less than 0.001), the b-wave amplitude 14% higher (p less than 0.001) and the standing potential 1007 microV higher (p less than 0.001) during intravitreal perfusion with dopamine in the other eye than during the preceding irrigation with PHS in that eye, possibly as a result of increasing dark adaptation.

Animals↗
PubMed1989

Effects of public day-care: a longitudinal study.

119 Swedish children were followed from their first year of life up to the age of 8. Most could be classified according to (a) type of day-care they had experienced during their first 7 years of life and (b) time of first entrance into day-care. At 8 years, the children were tested with aptitude tests and rated by their teachers on school performance and social and personal development. Hierarchical regression analyses and MANCOVAs were used in the statistical treatment. Time of entrance into day-care predicted children's cognitive and socioemotional development, controlling for sex and home background. Children with early day-care (entrance before the age of 1) were generally rated more favorably and performed better than children with late entrance or home care. There was a tendency for early center care to predict a more favorable outcome than other care.

Achievement↗
PubMed1989

Clear PMMA versus yellow intraocular lens material. An electrophysiologic study on pigmented rabbits regarding "the blue light hazard".

Pigmented rabbits were exposed for 3.5 h to light (retinal irradiance 60-70 mW/cm2, i.e. below the level of thermal damage) from a Xenon lamp, passing IR filters and a fiber optic system as well as a Perspex CQ (clear PMMA) IOL material in front of one of the eyes (the "PER" eye) and a yellow (blue light absorbing) filter (potential IOL material) in front of the other eye (the "YEL" eye). The difference in spectral distribution of light transmitted by the two filters may be important. Does the yellow filter offer significant protection against "the blue light hazard"? DC ERG recordings were performed before, 1 day after and 4-6 days after exposure. The c- (mainly pigment epithelium (PE)) and b-wave (neuroretina) amplitudes were measured and the cPER/cYEL as well as the bPER/bYEL ratios calculated. Both ratios were found to be reduced after exposure, for the c-wave 30-33% (p less than 0.05 - 0.001), and for the b-wave 12-20% (p less than 0.01 - 0.02). This means that both the PE and the neuroretina were injured in the PER eye, the PE more than the neuroretina. At day 4-6 the c- and b-wave ratios were found to have returned to initial levels, indicating that the damage was reversible to a large extent. Thus, the yellow filter offered a better protection than the Perspex material. There were no ophthalmoscopic fundal changes 1-2 h after exposure. After 1 day minimal changes were seen in 3/16 YEL eyes and somewhat more pronounced changes in 8/16 PER eyes, all in the central fundus. The conclusion is that in acute experiments and under the conditions applied the yellow filter protected the PE and the retina against photochemical light injury (mainly "the blue light hazard") significantly better than the Perspex material. Furthermore, the yellow filter was found to protect significantly better than a UV absorbing IOL material.

Animals↗
PubMed1988

Hereditary retinal degeneration in the Abyssinian cat: developmental studies using clinical electroretinography.

Electroretinography was performed in 10 Abyssinian cats, homozygous for a hereditary retinal degenerative disease but still with an ophthalmoscopically normal retina, and in 11 mixed-breed controls, all between the ages of 8 and 104 weeks. A significant reduction of maximum dark-adapted b-wave amplitude was found in affected kittens as young as 8-16 weeks when compared with controls, although there was no major difference in dark-adapted b-wave threshold or implicit time for the b-wave between affected and controls. For cats 33-104 weeks, similar results were obtained except for the b-wave threshold, which was elevated 2.5 log units in one of the affected cats. No significant difference in 30-Hz cone flicker responses were found between affected and controls at any age studied. In the time period 17-32 weeks affected Abyssinian kittens could not be differentiated from controls by means of the electroretinogram. The significant reduction in scotopic b-wave maximum amplitudes in young affected kittens (8-16 weeks) in conjunction with normal thresholds suggests an early drop-out of rods. It is clear that affected kittens can be differentiated electrophysiologically from controls long before there are ophthalmoscopic signs of retinal disease.

Aging↗
PubMed1986

Effects of intraocular perfusion with two alternating irrigation solutions on the simultaneously recorded electroretinogram of albino rabbits.

The direct current electroretinogram (DC-ERG) of 15 unilaterally vitrectomized albino rabbits was studied during continuous intraocular irrigation with a recently developed solution ('PHS') produced by Pharmacia Ophthalmics. The mean amplitudes of the b- and c-waves were somewhat lower than corresponding values of previously investigated reference subjects, but not statistically different. In 11 of the 15 rabbits PHS was then replaced by the commonly used balanced salt solution (BSS). The fluids were subsequently repeatedly alternated (PHS, BSS, PHS, BSS, PHS). During irrigation with BSS the average amplitude of the b-wave was reduced to 87% (p less than 0.02) and that of the c-wave to 63% (p less than 0.001) of the levels obtained during perfusion with PHS. In two rabbits the ERG was studied about one month after vitrectomy, where PHS-irrigation was used both during surgery and for 30 min after its completion. No marked differences were observed between the treated and the untreated eyes as to the b- and c-wave amplitudes at stable stages of the recording. Thus, judged by the ERG, retinal and pigment epithelial functions were influenced unfavorably by BSS, whereas they seemed to be well preserved with PHS. From this point of view PHS appears to be an excellent irrigation solution for vitreoretinal surgery that ought to be clinically tested.

Animals↗
PubMed1985

Progressive retinal atrophy in the Abyssinian cat: studies of the DC-recorded electroretinogram and the standing potential of the eye.

DC-recorded electroretinography (ERG) and direct recordings of the standing potential (SP) were performed on a group of normal cats and Abyssinian cats affected by a hereditary retinal degenerative disease with similarities to human retinitis pigmentosa. A significant reduction of a- and b-wave amplitudes was found at an early stage of disease at a time when there were no major alterations in the c-wave and SP. At later stages both the c-wave and the SP oscillations were significantly reduced or absent. These findings indicate a primary photo-receptor disorder. Threshold studies for the scotopic b-wave showed a loss of retinal sensitivity early in the disease at a time when 30 Hz flicker responses were normal, which could indicate an earlier involvement of the rods than of the cones. There were no major alterations in the timing of the ERG in the affected animals tested.

Action Potentials↗
PubMed1978

Subjective effects and vigilance after diazepam and oxazepam in normal subjects.

Twenty-two normal subjects were given single oral doses of diazepam 5 mg, oxazepam 15 mg and placebo in a double-blind cross-over trial. Subjective effects according to a rating scale and performance on a vigilance task were assessed. The results showed a difference between each of the two drugs and placebo, but none between the drugs, with regard to the vigilance test. The results from the rating of subjective effects showed an increase in "tiredness" for both drugs, and a decreased "well-being" for oxazepam.

Attention↗
PubMedDate not supplied

Corneal D.C. recordings of slow ocular potential changes such as the ERG c-wave and the light peak in clinical work. Equipment and examples of results.

A set-up for D.C. recordings of slow ocular potentials such as the c-wave of the electroretinogram (ERG) as well as the fast oscillation (FO), the light peak (LP) and the dark trough (DT) in both clinical and experimental work is described. It includes matched calomel half-cells connected by saline-agar bridges to a corneal contact lens on the eye and a reference chamber on the forehead, a low-drift differential-input D.C. amplifier, an A/D converter, a computer, a thermoprinter, a flexible disc memory, a plotter, and a device for light stimulation controlled by the computer. Examples of the usefulness of the set-up in clinical work are shown in the form of D.C. c-wave ERGs of normal subjects as well as of patients with vitelliform macular degeneration, choriocapillaris atrophy, and retinitis pigmentosa. The direct corneal recording of the FO and LP is demonstrated as well. The different origins of the standing potential (SP) of the eye, the ERG c-wave, the FO and the LP are reviewed briefly.

Computers↗
PubMedDate not supplied

Self-administration of amphetamine analogues in rats.

In rats self-injecting amphetamine (0.25 mg/kg/injection) at a stable level during daily 3 hr sessions, three different amphetamine analogues )phenmetrazine, diethylpropion and fenfluramine) were substituted for amphetamine, one at a time on different experimental days. Phenmetrazine (1.0 mg/kg/injection) and diethylpropion (2.0 mg/kg/injection) were self-administered but not fenfluramine (in doses of 0.1, 0.5 and 2.0 mg/kg/injection). It is concluded that amphetamine, phenmetrazine and diethylpropion have reinforcing properties, whereas fenfluramine has not.

Amphetamine↗