Search PubMed⌕ Search

Biomedical subjects

A Backman

Publications and source records attributed to A Backman.

At least 19 recordsLinked to original sources
PubMed2004

Degradation of 4-chlorophenol at low temperature and during extreme temperature fluctuations by Arthrobacter chlorophenolicus A6.

Low average temperatures and temperature fluctuations in temperate soils challenge the efficacy of microbial strains used for clean up of pollutants. In this study, we investigated the cold tolerance of Arthrobacter chlorophenolicus A6, a microorganism previously shown to degrade high concentrations of 4-chlorophenol at 28 degrees C. Luciferase activity from a luc-tagged derivative of the strain (A6L) was used to monitor the metabolic status of the population during 4-chlorophenol degradation. The A6L strain could degrade 200-300 mug mL(-1) 4-chlorophenol in pure cultures incubated at 5 degrees C, although rates of degradation, growth and the metabolic status of the cells were lower at 5 degrees C compared to 28 degrees C. When subjected to temperature fluctuations between 5 and 28 degrees C, A6L continued to degrade 4-chlorophenol and remained active. In soil microcosm experiments, the degradation rates were significantly faster the first week at 28 degrees C, compared to 5 degrees C. However, this difference was no longer seen after 7 days, and equally low 4-chlorophenol concentrations were reached after 17 days at both temperatures. During 4-chlorophenol degradation in soil, CFU and luciferase activity values remained constant at both 5 and 28 degrees C. However, once most of the 4-chlorophenol was degraded, both values decreased by 1-1.5 logarithmic values at 28 degrees C, whereas they remained constant at 5 degrees C, indicating a high survival of the cells at low temperatures. Because of the ability of A. chlorophenolicus A6 to degrade high concentrations of 4-chlorophenol at 5 degrees C, together with its tolerance to temperature fluctuations and stress conditions found in soil, this strain is a promising candidate for bioaugmentation of chlorophenol-contaminated soil in temperate climates.

Arthrobacter↗
PubMed2000

Assessment of spatial acuity at the fingertip with grating (JVP) domes: validity for use in an elderly population.

JVP domes are of a set of small grating surfaces recently introduced for cutaneous spatial resolution measurement. The gratings are placed on the skin and subjects are required to identify the orientation of grooves and bars. The finest grating whose orientations are discriminated reliably (75% correct) provides an estimate of the spatial resolution limit in the tested area. In the present study, we sought to determine the capacity of elderly subjects to resolve such grating stimuli in order to obtain normative data for this population. Thirty-two elderly individuals in good health (range: 60-88 years) were assessed for their ability to perceive grating orientation at the tip of the dominant index finger. Testing proceeded from the widest grating dome (3 mm) to the next (e.g., 2 mm), until the performance level dropped below 75% correct discrimination. The grating orientation task proved to be very difficult for most subjects and only a minority (14/32) was able to provide reliable reports of grating orientation even with presentation of the widest dome available (3 mm). Accordingly, individual grating resolution thresholds were often considerably higher (> 2.5 mm, n = 26) than values previously reported in young adults for the fingertip region (approximately 1 mm). These results suggest that the current set of grating domes may not be adequate for spatial acuity measurement at the fingertip of older adults. New larger grating dimensions should be added to the set presently available to improve their sensitivity for an older population.

Aged↗
PubMed1995

Osteitis caused by bacille Calmette-Guérin vaccination: a retrospective analysis of 222 cases.

To evaluate the frequency, clinical features, and prognosis of patients with osteitis caused by bacille Calmette-Guérin (BCG) vaccination, medical records from Finnish children based on nationwide registration from 1960 to 1988 were retrospectively analyzed. During the study period, three different BCG vaccine preparations were used. In 222 children, diagnostic criteria of BCG osteitis were fulfilled. The age at onset of BCG osteitis varied from 0.25 to 5.7 years. The most common sites of osteitis were metaphyses of the long bones. The lower extremity (58%) was affected more often than the upper (14%). Osteitis was situated in the sternum in 36 patients (15%) and in the ribs in 27 (11%). The frequency of BCG osteitis, but not the clinical parameters, was closely associated with the vaccine preparation used. Only 6 children were left with some sequelae. With adequate treatment, the prognosis for children vaccinated with BCG is good.

BCG Vaccine↗
PubMed1994

Osteitis after newborn vaccination with three different Bacillus Calmette-Guérin vaccines: twenty-nine years of experience.

Newborns in Finland have been vaccinated with Bacillus Calmette-Guérin (BCG) since the 1950s. Until the end of 1970 the vaccine was made from BCG strain Gothenburg by the Swedish BCG laboratory in Gothenburg and from 1971 on from the same strain in Copenhagen, Denmark. It was replaced by the Glaxo vaccine in 1978. Complications caused by BCG vaccination have been under follow-up, and the data have been collected from nationwide registers. In this study we analyzed the incidence rates of BCG osteitis between the years 1960 and 1988. From 1960 to 1970 the incidence rate was from 2.7 to 13.0/100,000 BCG-vaccinated infants (mean, 7.3; median, 6.9). The incidence increased during the years 1971 to 1978 when it varied between 15.3 and 72.9/100,000 BCG-vaccinated infants (mean, 36.9; median, 30.4). Since 1978 the incidence has varied between 1.7 and 10.1/100,000 BCG-vaccinated infants (mean, 6.4; median, 7.2). In Britain no reports of BCG osteitis have been published despite the use of the same Glaxo vaccine. Our results indicate that the incidence of BCG osteitis in a given population depends on the BCG vaccine used. The follow-up of BCG complications is an essential part of BCG vaccination program.

Animals↗
PubMed1989

The international collaborative study on the first international standard of birch (Betula verrucosa)-pollen extract.

A selected candidate international standard preparation of birch (Betula verrucosa)-pollen extract was studied together with other birch-pollen extracts in a multinational study involving 20 laboratories in 11 countries. The biologic activity of the extract had previously been demonstrated in quantitative skin prick testing. The study methods comprised RAST inhibition, histamine release, quantitative immunoelectrophoresis, isoelectric focusing, and other methods. The results from RAST inhibition were calculated as parallel-line assays with statistical tests for linearity and parallelism. Analysis of variance was applied to test the significance of differences between potency estimates. In all assay methods, the candidate standard could be used to assign relative potencies to other birch-pollen extracts. The candidate standard was adequately stable during 36 months of storage at or below 5 degrees C. On the basis of this study, the World Health Organization has established the preparation as the International Standard for birch-pollen extract with assigned units of 100,000 IU per ampule.

Binding, Competitive↗
PubMed1987

Safe immunization of allergic children against measles, mumps, and rubella.

A series of 135 subjects (134 children and one adult) with documented or suspected systemic allergy were prick-tested before a measles, mumps, and rubella (MMR) vaccination. Atopic eczema was documented in 68, asthma in 47, and cow's-milk allergy in 11 examinees; eight children were evaluated because of severe systemic reactions following diphtheria-pertussis-tetanus, measles, or inactivated polio (Salk) vaccinations. In one child, there was only a suspicion of general allergy. The undiluted MMR prick test gave negative reactions in 126 cases (93%). The highest rate of nonreactivity was observed in those with atopic eczema (96%) and in children with asthma (91%) or cow's-milk allergy (82%). All examinees with systemic reactions after other vaccinations also had negative prick-test reactions. A total of 122 (95%) of the 129 examinees were eventually vaccinated with MMR. No untoward reactions developed, except mild generalized urticaria or fever in two vaccinees. We conclude that at least 95% of children with common forms of systemic allergy can be vaccinated safely with MMR and, in general, that allergic diseases should not interfere with execution of the vaccination programs.

Adolescent↗
PubMed1987

Neonatal BCG vaccination and mycobacterial cervical adenitis in childhood.

Mycobacterial cervical adenitis is an uncommon disease in children in Finland. During 10 years, from 1977-1986, its incidence was of the order of 0.3/year/100,000 children. Of the 12 bacteriologically verified cases, M. avium-intracellulare was isolated in nine, M. malmoense in two and M. tuberculosis in only one case. Neonatal BCG vaccination seemed to protect children against non-tuberculous mycobacterial infection, especially at 1-4 years of age. In Sweden, where neonatal BCG vaccination has been discontinued, the incidence of non-tuberculous mycobacterial adenitis is at least 30 times greater.

Adolescent↗
PubMed1985

Allergic conjunctivitis, total and specific IgE in the tear fluid.

Twenty-three patients with allergic conjunctivitis caused by birch, timothy or mugwort pollen were examined for the presence of total and specific IgE in the tear fluid. In thirteen of the 23 patients IgE could be shown in the tears. Specific IgE antibodies against the causative pollens were present in the tear fluid of 8 of the patients. The relation between serum and tear IgE on one hand and serum and tear albumin on the other hand suggests local production of the specific IgE antibody.

Adolescent↗
PubMed1984

A new method for testing tuberculin skin reactivity--chamber test.

The Mantoux test and a chamber tuberculin test applied to the surface of the skin in 4 concentrations were performed on 229 children and 516 adults. The results were recorded at 72 hours. There was a significant correlation between the two tests. The chamber tuberculin test is technically easy, painless and atraumatic. It gives an opportunity of using a full range of concentrations of tuberculin resulting in a quantitative measurement of sensitivity in one and the same test procedure.

Adult↗
PubMed1984

Assay of the biologic activity of allergen skin test preparations.

We studied the biologic activity of allergen preparations using a method involving skin prick tests in humans and the use of HEP (histamine equivalent prick) units. Results were found to be dependent on the population groups used in assays. If populations are not carefully standardized, results may vary by 1 power of 10. Accuracy can also be improved by the use of suitable allergen standard reference preparations, but such were not available to us. Confidence ranges for the biologic activities were relatively wide and varied with the allergen preparation and the population group. Typically, the 95% confidence range included values from one-fifth to five times the estimated HEP value when the number of subjects in the assay was 30 to 50 persons. When the preparations representing the same source material (e.g., timothy pollen) were assayed simultaneously in one population group of this size, a twofold or larger difference in HEP values generally proved significant. An examination of 43 commercial products showed that allergen preparations with biologic activities declared in HEP units had a more uniform biologic activity than those assayed with traditional methods and units (PNU/ml or weight/volume).

Adolescent↗
PubMed1984

Do infections in infancy affect sensitization to airborne allergens and development of atopic disease? A retrospective study of seven-year-old children.

We studied 145 children aged 7 years, who had been at day-care centers for at least 3 months during the 2 first years of their lives. The group was compared with a matched population of 145 children cared for at home. Of the 290 children, 212 participated in all phases of the study, which included a questionnaire to parents, skin prick tests with seven allergens, and a clinical examination. Day-care-center children had twice as much otitis media in infancy as "home" children (P less than 0.001), and they also tended to have more other infections. On the other hand, day-care-center children did not have more eczema in infancy, more cumulated atopic disease by the age of seven, or more positive skin tests than home children. When the groups were combined, an increased prevalence of cumulated atopic disease and positive skin tests was found in children with infections in infancy. We conclude that under the conditions of this study infections in infancy did not facilitate the development of hypersensitivity to allergens and atopic disease. The linked tendencies to develop infections and atopy could depend on some third factor.

Allergens↗