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Biomedical subjects

J Olsson

Publications and source records attributed to J Olsson.

At least 91 records · Page 5Linked to original sources
PubMed1989

The effect of perimetric experience in normal subjects.

Two groups of normal subjects were submitted to repeated automated static threshold perimetry. Perimetric results were strongly affected by the level of experience in some subjects; in the majority, however, the effect of experience was small. Initial field tests often showed high numbers of depressed points. Sensitivity increased with perimetric training, particularly between the first sessions. Those subjects who improved most started low, gradually approaching normal levels with experience. Learning effects were more pronounced peripherally than paracentrally and "untrained" fields characteristically showed concentric contraction with numerous points with low sensitivity peripherally. An important practical conclusion is to allow repeated testing of all inexperienced patients in whom initial fields do not agree with clinical findings. A chart showing a concentrically narrowed field should be viewed with particular suspicion. Furthermore, a single initial field may constitute an inadequate baseline for clinical follow-up.

Adult↗
PubMed1989

Visual field interpretation with empiric probability maps.

Automated visual field charts may be difficult to interpret partly because of the magnitude and complex nature of normal threshold variability. We devised two types of empiric probability maps in which this variability is taken into account and the significances of measured threshold values are displayed. These maps are highly sensitive to nonobvious but significant paracentral field loss but will at the same time deemphasize false-positive patterns commonly found more peripherally. They also frequently show field defects before these are obvious in conventional threshold printouts. In addition, they differentiate between generalized loss of sensitivity and localized field defects.

Cataract↗
PubMed1989

X-linked megalocornea: close linkage to DXS87 and DXS94.

In a family in which X-linked megalocornea is segregating, the disease locus was found to be closely linked to DXS87 (zeta max = 3.91, theta max = 0.00) and DXS94 (zeta max = 3.34, theta max = 0.00) in Xq21.3-q22.

Corneal Diseases↗
PubMed1989

The influence of saliva on infection of the human mouth by mutans streptococci.

The relationship between oral implantation of Streptococcus mutans IB1600 (serotype c) and Streptococcus sobrinus OMZ65 (serotype g), the aggregating activity of saliva, and its influence on the adherence of these bacterial strains in vitro was examined in seven human subjects. All the saliva samples aggregated strain IB1600 but not strain OMZ65 cells. Whole saliva from subjects with low levels of infection by Strep. mutans aggregated strain IB1600 to a greater degree than did whole saliva from those who were readily infected. Whole saliva from subjects most resistant to infection supported the adsorption of the highest number of either strain IB1600 or OMZ65 to hydroxyapatite surfaces. Thus the ability of whole saliva to aggregate Strep. mutans may influence the ability of these microorganisms to infect the mouth.

Adult↗
PubMed1989

Some salivary factors in insulin-dependent diabetics.

The aim of the study was to compare salivary flow rate, salivary pH, buffer capacity of the saliva, salivary glucose content, and number of Candida albicans, lactobacilli, and Streptococcus mutans in the saliva in age- and sex-matched adult long- and short-duration insulin-dependent diabetics and non-diabetics. Ninety-four long-duration and 86 short-duration diabetics and 86 non-diabetics, aged 20-70 years, participated in the study. Paraffin-stimulated whole saliva was collected. Both long- and short-duration diabetics had a decreased salivary flow rate and an increased salivary glucose content compared with non-diabetics. However, the differences were small. There were no significant differences between the groups in salivary pH, buffer capacity, or bacterial counts.

Adult↗
PubMed1989

Does omeprazole improve antimicrobial therapy directed towards gastric Campylobacter pylori in patients with antral gastritis? A pilot study.

This double-blind pilot study has been undertaken in order to investigate the effect of amoxicillin and pronounced suppression of gastric acid secretion on mucosal colonisation with Campylobacter pylori (CP). Twenty four CP-positive patients were included in the study and assigned to 14 days of treatment in either one of the following three therapy groups: Group 1: Omeprazole 40 mg o.m. + Amoxicillin 750 mg b.i.d (9 pat); Group 2: Omeprazole 40 mg o.m. (8 pat); Group 3: Amoxicillin 750 mg b.i.d (7 pat). Gastroscopy with biopsy for culture and histology was performed pre-entry, at cessation of therapy and four weeks later. In the group receiving omeprazole and amoxicillin in combination 5 out of 8 patients were negative for CP four weeks after stopping treatment, while in the amoxicillin and the omeprazole groups respectively one (1/7) and none (0/8) were negative. Except for one patient who was withdrawn because of severe diarrhoea, only minor adverse effects occurred.

Adult↗
PubMed1988

Implantation and cariogenicity in hamsters of Streptococcus mutans with different hydrophobicity.

Strains of Streptococcus mutans with different surface hydrophobicity were examined for their ability to colonize and induce carious lesions in hamsters given a high sucrose diet. In a short-term experiment the hydrophobic strain GW showed almost an identical colonization pattern compared to the hydrophilic strain GW36. Streptomycin resistant variants of GW and GW36 implanted at a much slower rate than the parent strains. Differences in caries score were observed between the strains. The cariogenicity of the strains seemed to be dependent on early colonization.

Animals↗
PubMed1988

Influence of pH on the suspension stability of some oral bacteria.

The purpose of the present study was to investigate the suspension stability of some oral bacteria at some clinically relevant pH levels. Through determinations of the electrophoretic mobility and sedimentation behavior at pH 5, 6, and 7, it was shown that within this pH range estimations of both the zeta-potentials and colloidal stability were pH-dependent for the bacteria and bacterial suspensions tested. The observations are in line with the DLVO theory for lyophobic sols and indicate that bacteria behave like colloidal particles when suspended in certain media. The colloidal behavior further seemed to vary in relation to bacterial species and strains.

Actinomyces↗
PubMed1987

Normal variability of static perimetric threshold values across the central visual field.

We assessed the variability of results in normal subjects of computerized static threshold perimetry of the central 30 degrees field. Variability of measured threshold values was highly dependent on eccentricity. This included variability among individuals, test-to-test variability within individuals, and intratest variability. All values were significantly larger in the midperiphery than centrally. We found that the mean sensitivity decrement with age was eccentricity dependent, so that the age-corrected normal visual field became not only depressed but also steeper with age. Distributions of individual pointwise deviations from the age-corrected normal mean thresholds were significantly nongaussian. The dependency of variability on test point location, the nongaussian distributions of deviations from age-corrected means, and the variability of age-induced sensitivity reduction should all be considered in the interpretation of computerized visual fields, and particularly in the design of statistical programs for field analysis. Programs not considering these factors are likely to result in misleading analyses.

Adult↗
PubMed1987

Thoracolumbar epidural anaesthesia blocks the circulatory response to laryngoscopy and intubation.

Laryngoscopy and endotracheal intubation cause a stress reaction resulting in an increase in heart rate and systemic blood pressure. This haemodynamic response is considered to be due to a sympathetic discharge caused by stimulation of the upper respiratory tract. This stress reaction during laryngoscopy and endotracheal intubation was studied in patients with total thoracolumbar epidural anaesthesia (EDA). Nine patients with thoracolumbar EDA including at least the segments T1 to L2 were compared to seven patients without EDA during induction of general anaesthesia. The epidural anaesthesia was achieved with 2% mepivacaine with adrenaline. General anaesthesia was induced with thiopentone 4-5 mg/kg followed by 100 mg suxamethonium. The highest blood pressure value during the first 2 min after intubation was compared to the value immediately before intubation. The epidural anaesthesia caused a reduction of the mean arterial blood pressure (MAP) by 25%, and a reduction of the heart rate (HR) by 7%, but neither the induction with thiopentone nor the laryngoscopy and intubation caused any changes in mean arterial blood pressure or heart rate. However, in the control group MAP increased 29% and HR 16% following intubation. Thus, the T1-L2 epidural anaesthesia with 2% mepivacaine with adrenaline blocked the blood pressure reaction to laryngoscopy and intubation, and consequently the efferent sympathetic nervous system was completely blocked.

Adult↗
PubMed1986

Oral implantation of Streptococcus mutans in man with and without prior chlorhexidine mouthrinses.

Oral implantation of streptomycin resistant S. mutans was enhanced when chlorhexidine mouthrinses were applied before implantation. The difference in recovery of implanted bacteria between implantations with and without prior chlorhexidine mouthrinses was significant 9 days (P less than 0.05), 15 days (P less than 0.05) and 28 days (P less than 0.01) after implantation. After 28 days implanted bacteria were no longer detected in any of the 20 test subjects when chlorhexidine was not used prior to implantation, but persisted in 11 subjects when chlorhexidine was used.

Chlorhexidine↗
PubMed1985

Effect of local and parenteral immunization on implantation of Actinomyces viscosus T6 in rats.

Groups of rats immunized in the vicinity of the major salivary glands or immunized intraperitoneally with Actinomyces viscosus T6 and their sham-immunized controls were infected with the homologous bacterium. Significantly higher levels of salivary and serum antibody were induced by intraperitoneal than by salivary gland immunization. There were also significant inverse correlations between the levels of salivary and serum antibody and the levels of implantation of A. viscosus T6. The level of implantation of A. viscosus T6 was significantly lower in the immunized animals than in the controls. However, antibody had limited capacity to inhibit the establishment of this bacterium.

Actinomyces↗
PubMed1985

Transcutaneous carbon dioxide and oxygen tension measured at different temperatures in healthy adults.

Transcutaneous carbon dioxide tension (tc-pco2) at 37, 39, 41, 43, and 45 degrees C, and transcutaneous oxygen tension (tc-po2) at 41, 43, and 45 degrees C were measured simultaneously in 10 healthy adults during hyperventilation and inhalation of O2/CO2 gas. Nine electrodes were applied to each subject: Five CO2 electrodes, one O2 electrode, and three combined O2/CO2 electrodes. The CO2 electrodes had negligible temperature coefficients in the calibration gases, but the O2 electrodes showed an increase in po2 of 4.5% per degree C. With skin application, tc-pco2 increased approximately 4% per degrees C between 37 and 45 degrees C, which is close to the anaerobic temperature coefficient of pco2 in blood. The tc-po2 increases on the skin with increasing temperature appeared to be more dependent on changes in blood flow in skin, but in the temperature range 43 to 45 degrees C, tc-po2 showed the expected decrease in the temperature coefficient with increasing po2. The correlation between transcutaneous and capillary pco2 was close at all transcutaneous electrode temperatures, even 37 degrees C, provided the skin was preheated (via the electrode) to 45 degrees C. For tc-po2, an electrode temperature of at least 43 degrees C was necessary to produce a reasonable correlation between tc-po2 and capillary po2. The combined O2/CO2 electrodes measured slightly higher pco2 values than the single CO2 electrodes, but there were no differences in po2 readings, stabilization time, imprecision, or electrode drift between the two electrode types. The imprecision (CV, %) of tc-pco2 and tc-po2 measurements was approximately twice that of the corresponding capillary blood-gas measurements.

Adult↗
PubMed1984

Oral implantation in humans of Streptococcus mutans strains with different degrees of hydrophobicity.

The more hydrophobic, rough-colony-forming, streptomycin-resistant Streptococcus mutans parent strains GW Smr and LK Smr and the less hydrophobic, smooth-colony-forming, streptomycin-resistant variant strains GW36 Smr and LK36 Smr were implanted in oral cavities. Strains GW Smr and LK Smr implanted significantly better than strains GW36 Smr and LK36 Smr. The hydrophobicity of and the colony morphology formed by the different S. mutans strains did not seem to be affected throughout the experiment.

Adhesiveness↗
PubMed1984

Biochemical and immunological differences between hydrophobic and hydrophilic strains of Streptococcus mutans.

Hydrophobic strains of Streptococcus mutans were compared with paired variants showing reduced hydrophobicity. Extracts of hydrophobic cells contained a number of high-molecular-weight proteins which were not present on cells with decreased hydrophobicity. The proteins were found in purified cell walls, suggesting that they are located on the bacterial surface. Trypsin treatment of whole cells destroyed the proteins and reduced the hydrophobicity. Chemical analysis did not reveal any marked differences in the proportion of cell wall constituents. The amino acid compositions and lipoteichoic acid contents of hydrophobic and hydrophilic cell walls were similar. Culture supernatants from the hydrophilic variants contained high-molecular-weight proteins similar to those extracted from the cell walls of the hydrophobic parent strains, indicating that the variants were impaired in their ability to incorporate the hydrophobicity-associated proteins into the cell wall. The dominant protein had a molecular weight of 190,000, similar to that of antigen I/II (B) of S. mutans.

Alkanes↗