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Biomedical subjects

A Karlsson

Publications and source records attributed to A Karlsson.

At least 271 records · Page 15Linked to original sources
PubMed1984

Intrathyroidal HLA-DR expression and T lymphocyte phenotypes in Graves' thyrotoxicosis, Hashimoto's thyroiditis and nodular colloid goitre.

Thyroid surgical biopsies from 21 individuals were examined by a double immunoenzymatic technique with respect to HLA-DR expression and lymphocytic infiltration. HLA-DR positive thyrocytes were observed in two examined Hashimoto goitres and in nine of 11 specimens from patients with Graves' disease. HLA-DR positive thyrocytes were localized to areas harbouring infiltrating lymphocytes, whereas regions with no lymphocytes only rarely expressed HLA-DR antigens. In two specimens of nodular goitre HLA-DR positive thyrocytes were observed in the vicinity of lymphocytic infiltration. Tissues from another three nodular goitres, from one follicular adenoma and from two normal individuals contained no HLA-DR positive thyrocytes and no or only a few lymphocytes. The lymphocytic infiltrates were dominated by cells with the Leu 3a helper/inducer phenotype irrespective of underlying disease, although most pronounced in Hashimoto's thyroiditis. The results indicate that HLA-DR antigens is expressed on thyrocytes in thyroid disorder. The extent of expression correlated with lymphocytic infiltration, which suggests that the two findings are related and of importance for the development of thyroid autoimmunity.

Adolescent↗
PubMed1983

No cytogenetic effects in lymphocytes of stainless steel welders.

In 24 manual metal arc stainless steel welders (means: exposure time 19 years, 100 electrodes/d, air chromium level 81 micrograms/m3, urinary chromium 47 mumol/mol creatinine) and 24 matched referents, lymphocytes in peripheral blood were analyzed for cytogenetic effects. No statistically significant differences were observed as to frequency of cells with breaks and fragments (1.5% for the welders, 1.9% for the referents); gaps and isogaps (1.8 vs 2.0%); interchanges, dicentrics, rings and markers (0.8 vs 0.5%); total number of cells with structural aberrations (4.1 vs 4.4%); hyperdiploidy (0.3 vs 0.2%); or total number of cells with aberrations (4.4 vs 4.6%). Neither were there any differences in the frequencies of micronuclei (7.8 vs 7.9 per mille) or sister chromatid exchanges (11 vs 12 per cell) in lymphocytes of peripheral blood.

Adult↗
PubMed1982

Autoantibodies to the insulin receptor and insulin-resistant diabetes.

Autoantibodies to the insulin receptor are a rare cause of insulin-resistant diabetes, but when they occur they produce a profound clinical syndrome. These antibodies block insulin binding, immunoprecipitate solubilized insulin receptors, and their acute effect is to mimic the biological effects of insulin. However, prolonged exposure of cells to these antibodies produces a state of insulin resistance. Since the antigen to which the antibody is directed is relatively well-characterized, many of the observations in this syndrome can serve as a model for elucidating molecular mechanisms in other diseases with antibodies against membrane components. The autoantibodies to the insulin receptor have also provided valuable probes in the study of insulin receptor structure and insulin action.

Adipose Tissue↗
PubMed1979

Hyperparathyroidism associated with distal tubular dysfunction but intact reabsorption of protein in the proximal tubules.

The urinary output of beta 2-microglobulin was measured in ten hypercalcemic patients undergoing surgery because of hyperparathyroidism. In three subjects the beta 2-microglobulin excretion was abnormally increased and in seven patients it was normal before surgery. Three of these seven patients displayed markedly impaired distal tubular function with a reduced urinary concentration capacity. After surgery all patients became normocalcemic and the urinary concentrating capacities improved. The beta 2-microglobulin excretion, on the other hand, remained unchanged. Thus, hypercalcemia per se does not readily affect the proximal tubular function of reabsorbing low molecular weight proteins. "Tubular proteinuria", if found in patients with hypercalcemia, should be suspected to reflect damage to the kidney by additional mechanisms.

Aged↗
PubMed1978

Serum beta-2-microglobulin in Sjögren's syndrome.

The serum concentration of beta-2-microglobulin was determined with a radioimmunoassay in 52 patients with keratoconjunctivitis sicca, 29 of whom had Sjögren's syndrone. Eleven (38%) of the patients with Sjögren's syndrome had high serum values. These cases had a higher mean age and a higher frequency of the complete triad of Sjögren's and of antinuclear antibodies than had the lower value cases. The sicca components per se did not seem to influence the serum concentration of beta-2-microglobulin. Most of the few complications occurred in patients with high values.

Adolescent↗
PubMed1976

Urinary excretion of beta2 microglobulin after the induction of a diuresis. A study in healthy subjects.

An increased diuresis was induced in each of four healthy subjects by intravenous infusion of urea, saline and sodium bicarbonate and by an oral water load. The excretion of a low molecular weight protein (LMW-protein), beta2-Microglobulin (beta2mu), was determined by a radioimmunoassay, the urinary concentrations of the protein being in the range 0.007-0,3 mug/ml. The hourly excretion of beta2 mu was not significantly influenced by varying loads of water, sodium, and osmoles which suggests that the tub ular reabsorption of LMW-proteins is stable under these conditions and that even a moderately increased excretion of such proteins may reflect a distrubed proximal tubular function.

Beta-Globulins↗
PubMedDate not supplied

The phagocyte chemiluminescence paradox: luminol can act as an inhibitor of neutrophil NADPH-oxidase activity.

The chemiluminescence system amplified by luminol or isoluminol is a sensitive and widely used method for determination of respiratory burst products generated by the NADPH-oxidase in phagocytes. The present study shows that luminol, but not isoluminol, can inhibit the release of oxygen metabolites generated by human neutrophil NADPH-oxidase. The difference in structure between luminol and isoluminol (rendering luminol more lipophilic than isoluminol, and thereby membrane-permeable), is suggested to determine indirectly whether or not the molecule is inhibitory. Luminol was shown to have an increased inhibitory effect after preincubation of neutrophils on a surface of aggregated IgG, suggesting that the cells can be transferred from a 'luminol-insensitive' to a 'luminol-sensitive' state. Since luminol had no inhibitory effect in a cell-free NADPH-oxidase system, it is likely that it interferes with the signal transduction pathway, leading to assembly and/or activation of the oxidase. As a consequence of the present results, showing that luminol but not isoluminol can inhibit NADPH-oxidase activity, we suggest that isoluminol is used in future studies of superoxide anion release from phagocytes.

Cell-Free System↗
PubMedDate not supplied

CO2-dependent fermentation of phenol to acetate, butyrate and benzoate by an anaerobic, pasteurised culture.

Fermentative degradation of phenol was studied using a non-methanogenic, pasteurised enrichment culture containing two morphologically different bacteria. Phenol was fermented to benzoate, acetate and butyrate and their relative occurrence depended on the concentration of hydrogen. Proportionately more benzoate was formed with high initial levels of H2. The influence of PH2 on the fermentation pattern was studied both in dense cell suspensions and in growing cultures by addition of hydrogen. An increase in growth yield (OD578) was observed, compared to controls, as a consequence of phenol degradation; however, the increase was less in H2-amended treatments, in which most of the phenol ended up as benzoate. The degradation of phenol in the dense cell suspension experiments was dependent on CO2. Benzoate was not degraded when added as a substrate to the growing culture. This is, to our knowledge, the first report concerning the fermentative degradation of phenol to nonaromatic products.

Acetates↗
PubMedDate not supplied

Bicycle injuries in Western Sweden: a comparison between counties.

The objectives of the study were to investigate whether there are differences in the incidence of bicycle-related injuries by geographic district (county), age, and gender in Sweden's Western Road Administration Region, and to utilize any detected differences to suggest priorities for intervention and prevention. Injury data come from the Swedish national hospital-discharge registry and a specialized national register of occupational injuries. Both bodily injuries in general and head injuries in particular show intra-regional differences. The rural part of Skaraborg County was shown to have a significantly higher injury incidence than other parts of the Western Region. Females generally show a lower incidence than males, but older women are more likely to be seriously injured than younger (age-related differences being greater than for males). Some striking findings were found with regard to occupational differences. Females sustain more work-related bicycle injuries than males. Head injuries account for more than half of the bicycle injuries in the Western Region that require hospitalization. All this indicates that targeted measures are required. Some studies have shown that the use of bicycle helmets reduces the incidence of head injuries, the degree of their severity, and the number of bicycle-related fatalities. There is a need for mandatory helmet-wearing legislation, which must go hand-in-hand with special efforts to reach groups with a low rate of helmet wearing, in particular those in the middle age range. Although the grown-up/older cycling population has been the subject of targeted action in some countries, the focus of preventive activity has generally been on children. The results of the study suggest the need for further injury-related research into adult cycling.

Accident Prevention↗
PubMedDate not supplied

Phosphorylation of nucleosides and nucleoside analogs by mammalian nucleoside monophosphate kinases.

Nucleoside monophosphate kinases catalyze the reversible phosphotransferase reaction between nucleoside triphosphates and monophosphates, i.e., monophosphates are converted to their corresponding diphosphate form. These enzymes play an important role in the synthesis of nucleotides that are required for a variety of cellular metabolic processes, as well as for RNA and DNA synthesis. Human tissues contain a thymidylate kinase, a uridylate-cytidylate kinase, five isozymes of adenylate kinase, and several guanylate kinases. Nucleoside monophosphate kinases are also required for the pharmacological activation of therapeutic nucleoside and nucleotide analogs. This overview is focused on the substrate specificity, tissue distribution, and subcellular location of the mammalian monophosphate kinases and their role in the activation of nucleoside and nucleotide analogs.

Animals↗
PubMedDate not supplied

Immune factors, dental amalgam, and low-dose exposure to mercury in Swedish adolescents.

Occupational high-dose exposure to metallic mercury can cause immune disturbances in sensitive individuals. Whether low-dose exposure to inorganic mercury from dental amalgam has this effect in humans is one of the issues related to the concept of oral galvanism and is supported by results of animal studies. This study explored some cellular immune factors (B- and T-lymphocytes, T4, T8, monocytes, neutrophilic, eosinophilic, and basophilic granulocytes, and large unstained cells) and some humoral immune factors (immunoglobulins IgG, IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgE, albumin, alfa-1-antitrypsin, orosomucoid, haptoglobin, and antinuclear antibodies) in 41 healthy 15-y-old schoolchildren. The relationship between these factors and amalgam fillings and mercury concentrations in plasma (P-Hg) were investigated. A low, but significant correlation (r = 0.40, p < .05) was found between the number of amalgam surfaces and the P-Hg values, which were low for both sexes (median value = 1.8 nmol/l). There was no significant influence of the number of amalgam surfaces or P-Hg on the immune factors tested, except random findings. The girls had significantly higher values of T8, IgG, and IgG1 than the boys.

Adolescent↗