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Biomedical subjects

L Andersson

Publications and source records attributed to L Andersson.

At least 307 records · Page 17Linked to original sources
PubMed1990

Immunocytochemical localization of the erythroid glucose transporter: abundance in tissues with barrier functions.

We investigated the cellular localization and tissue distribution of the glucose transporter protein in the nervous system of the monkey and rat, and in other tissues of the rat, by immunocytochemical methods with monoclonal and polyclonal antibodies to the glucose transporter of human erythrocytes. We found intense immunostaining, indicating a high density of the glucose transporter, in all intraparenchymal blood vessels of the brain and spinal cord, in pial vessels, and in endoneurial capillaries of peripheral nerves, nerve roots, and dorsal root ganglia. Larger blood vessels at the base of the brain and in major fissures did not stain. The only intraparenchymal brain microvessels that did not immunostain were in circumventricular organs. There was no specific immunostaining of neurons or glia, except for tanycytes in the floor of the third ventricle, which immunostained intensely. Vessels of the choroid plexus did not stain, but the choroid epithelium, especially its basal membranes, stained. The only non-neural organ where immunostaining was evident in its microvessels was the testis. In addition to the endothelium of neural and testicular tissues, there was immunostaining in certain epithelial tissues, such as the perineurium of peripheral nerves and nerve roots, the epithelium of the ascending loop of Henle in the kidney, and the epidermis of the skin. Based on these findings, we hypothesize that a high density of the erythroid-type glucose transporter is inherent to many endothelial and epithelial cells that are joined by occluding junctions. However, other epithelial tissues with known occluding intercellular junctions that lack the erythroid-type of glucose transporter may have other types of glucose transporter proteins.

Animals↗
PubMed1989

A cellular and functional split in the DRw8 haplotype is due to a single amino acid replacement (DR beta ser 57- asp 57).

The single DR beta chain gene of the DRw8 haplotype has been suggested to carry both the DRw8 and the DRw52 epitopes. Cellular typing has shown that the DRw8 haplotype can be split into three subtypes, Dw8.1, Dw8.2, and Dw8.3, presumably due to a polymorphism in the DRw8 beta chain. Furthermore, Dw8.1 and Dw8.2 cells present influenza virus antigen to different T-cell clones. In the present study, DRw8/Dw8.2 beta chain cDNA was cloned and characterized. A comparison of this sequence with a partial DRw8/Dw8.1 beta chain gene suggested that the DRw8 split is due to a single amino acid replacement of ser57-asp57 caused by three nucleotide substitutions in the same codon. In most DR haplotypes, two expressed DR beta chain genes exist. Comparing the nucleotide sequence of the single beta gene in the DRw8 haplotype to those of other DR beta genes revealed that the DRw8 beta gene sequence is most closely related to the DRB1 genes of the DR3, 5, and w6 haplotypes. However, the comparisons also showed that it was not possible from sequence similarities to divide the DR beta genes into two or more distinct allelic series.

Amino Acid Sequence↗
PubMed1989

Biological activity of saponins and saponin-like compounds from starfish and brittle-stars.

Twenty-four saponins and saponin-like compounds, isolated from starfish and brittle-stars, have been tested in four in vitro tests, based upon bacterial and cell tissue cultures. Saponin-like compounds from brittle-stars have previously not been tested for biological activity. In an antibacterial test based on an agar diffusion test, the Gram positive bacterium S. aureus was affected by the polyhydroxylated steroidal glycosides, polyhydroxylated sterols and disulfated sterols. However, none of the 21 compounds tested were active against the Gram negative bacterium E. coli. In a cytotoxicity test all 21 compounds tested influenced the cells at a concentration of 100 micrograms/ml, while the cells were unaffected at 1 microgram/ml. In an antitumor test, 16 compounds were tested on two lymphoma cell lines. Inhibition of cell growth, at a concentration of 5 ng/ml, was seen for three polyhydroxylated sterols, in one cell line. Weak activity was seen in an antiviral test at a concentration of 10 micrograms/ml.

Animals↗
PubMed1989

Case-referent study of cystic ovaries as a risk indicator for twin calvings in dairy cows.

The association between cystic ovaries and twin births in dairy cows was analyzed in an epidemiologic study. The case-referent study design was chosen. The cases were all twin-bearing cows during the observation period. Two different groups of cows giving birth to single calves were used as controls. One group consisted of cows from the same herds as the twin-bearing cows; the second group consisted of cows randomly selected from the entire population. The frequency of cystic ovaries was significantly higher in control cows from herds with twin-bearing cows than in control cows randomly selected from the general population. This finding suggests an indirect association between the occurrence of cystic ovaries and the birth of twins. The direct association between cystic ovaries and birth of twins was evaluated by odds ratio. The magnitude of this measure varied according to breed and the control group used for calculation. A biological explanation for this finding could be that the frequency of intrauterine death and resorption of one twin fetus differs among breeds and cows with or without a history of cystic ovarian disease.

Journal Article↗
PubMed1989

Localization of a critical restriction site on the I-A beta chain that determines susceptibility to collagen-induced arthritis in mice.

Type II collagen-induced arthritis (CIA) in mice is an autoimmune experimental model for rheumatoid arthritis. Susceptibility to CIA is associated with certain major histocompatibility complex class II haplotypes. The two very closely related haplotypes H-2q and H-2p differ in susceptibility to CIA. Only mice of H-2q (DBA/1, B10G strains) but not mice of H-2p-expressing strains (like strain B10P) develop CIA and an autoimmune response to type II collagen (CII) after immunization with CII. In contrast to H-2p, the H-2q haplotype does not express I-E molecules. The purpose of the present study was to identify, at the molecular level, the structures on major histocompatibility complex class II molecules determining susceptibility to CIA and CII responsiveness. We first excluded the possible suppressive involvement of Ep or Ap molecules by showing that F1 hybrids between H-2p and H-2q haplotype strains, expressing Ep and Ap, are responders to CII and fully susceptible to CIA. Secondly, because A alpha chains appear identical, we sequenced the A beta first-domain exons of p and q allotypes and found only four diverging amino acids in the predicted amino acid sequence. These variable residues were closely located at positions 85, 86, 88, and 89 at the end of the postulated alpha-helix, which is of importance for interactions with the antigenic peptide and the T-cell receptor. We suggest that this region is a critical major histocompatibility complex restriction site for CIA and CII responsiveness in H-2q mice as compared with H-2p mice. The CIA will now be an excellent autoimmune model for studies on interactions between autoantigenic peptide, autoreactive T cells, and a particular major histocompatibility complex molecule, as has been postulated to be the initial event also in rheumatoid arthritis.

Amino Acid Sequence↗
PubMed1989

A randomized study of secondary prevention of early stage problem drinkers in primary health care.

The subjects were recruited from participants in a health examination of random samples of the adult population in Stockholm county. Those aged 18-64 years who admitted a high alcohol consumption (greater than 40 g 100% ethanol/day) among men and greater than 30 g among women) or had an elevated value of serum-gammaglutamyltransferase (GGT) (cut-off point 1.0 microkatal/l for men and 0.6 microkatal/l for women) or had certain other indications of a high alcohol consumption were included. More severe cases, and those with an elevated GGT due to reasons other than alcohol, were excluded. The remaining subjects, 70 men and 13 women, were allocated at random to either an intervention or a comparison group. An elevated GGT was the main inclusion criteria. The subjects in the comparison group were advised by the general practitioner to cut their alcohol consumption, while those in the intervention group made further visits to their general practitioner, who gave general support and used an elevated GGT as an indication of the recent level of alcohol consumption at consecutive visits. There were three visits on average, so we are comparing a group receiving advice with a group receiving further minimal intervention. At the one-year follow-up there were greater, however not significant, reduction in GGT-level, in self-reported alcohol consumption and in a 'problem index' in the minimal intervention group than in the comparison group.

Adolescent↗
PubMed1989

Association between serum esterase (Es) type and starting proportion in Swedish Trotters: further observations.

A study was carried out to attempt to explain the basis of the association between the Es locus and starting proportion in Swedish Trotters which had been observed previously. The effect of Es genotype on starting proportion has diminished among horses born in the late 1970s. There are indications that the incidence of leg lesions varies between Es genotypes. If this is true, it is possible that the decreasing effect of the Es locus on starting proportion is due to the environmental changes which have been made at race tracks in the early 1980s to reduce the strain on the legs of the trotters.

Animals↗
PubMed1989

Selection for polymorphism in the antigen recognition site of major histocompatibility complex class II molecules.

The genetic basis for the extensive polymorphism of major histocompatibility complex (MHC) class II molecules was investigated by statistical analysis. Nucleotide sequences of human DQA1, DQB1, DRB1, and DRB3 genes and murine A alpha, A beta, and E beta genes were used. The results show that polymorphism is selected for in the antigen recognition site of class II molecules since replacement substitutions in this region were found to occur at a significantly higher frequency than expected in the absence of selection. In contrast, replacement substitutions are selected against in the remaining part of the first domain exon and in the second domain exon. Furthermore, comparing the sequence variability pattern among different class II alpha and beta sequences, using a variability index for each residue, showed that, with few exceptions, highly polymorphic residues occur in the antigen recognition site. There was a strong and highly significant correlation in the variability pattern in the homologous DRB/E beta sequences but not for DQB/A beta or DQA/A alpha sequences. This difference may be related to the fact that both alpha and beta chains of DQ/A molecules are polymorphic, while only beta chains of DR/E molecules vary.

Amino Acid Sequence↗
PubMed1989

A twin study of autism in Denmark, Finland, Iceland, Norway and Sweden.

The Nordic countries were screened for the occurrence of cases of autism with a same-sexed twin under age 25 years. Twenty-one pairs (11 monozygotic and 10 dizygotic) of twins and one set of identical triplets were found and extensively examined. The concordance for autism by pair was 91% in the monoygotic and 0% in the dizygotic pairs. The corresponding concordances for cognitive disorder were 91% and 30%, respectively. In most of the pairs discordant for autism, the autistic twin had more perinatal stress. The results lend support for the notion that autism sometimes has a hereditary component and that perinatal stress is involved in some cases.

Adolescent↗
PubMed1989

Progression of root resorption following replantation of human teeth after extended extraoral storage.

Avulsed human permanent teeth subjected to a minimum of 1 h dry extraoral storage before replantation were followed radiographically for an average of 4.8 years. The depth of root resorption cavities was assessed using a radiographic index, and the rate of root resorption was defined as the index change over time. The frequency of inflammatory and replacement resorption was determined at each observation time. Replacement resorption increased in frequency with time in all patients. In teeth endodontically treated within 3 weeks of replantation, minimal inflammatory resorption was found regardless of the age of the patients. In teeth where endodontic treatment was performed more than 3 weeks after replantation, the frequency of inflammatory resorption was significantly higher in young patients but not in older patients, up to more than 3 years after replantation. The rate of root resorption was found to be related to age. In patients 8-16 years old at the time of avulsion the rate of root resorption was significantly higher compared with patients 17-39 years old. Age had a higher impact on the rate of root resorption compared with the delay in endodontic treatment after replantation. It was concluded that a tooth replanted with a necrotic periodontal membrane will become ankylosed and resorbed within 3-7 years in young patients, whereas a tooth replanted under similar conditions in older patients may remain in function for a considerably longer time.

Adolescent↗
PubMed1989

Neuropsychiatric effects of low exposure to styrene.

Workers exposed to styrene concentrations of about 50 mg/m3 at a plant manufacturing reinforced polyester boats were examined for neuropsychiatric symptoms both in close connection with exposure and also seven months after exposure had ceased. Physical workload is important for the uptake of styrene and was about 50 W at this plant. On the first occasion, after one week with no exposure, the workers reported a high frequency of neuropsychiatric symptoms such as fatigue, irritation, and forgetfulness whereas seven months later the frequency of these symptoms was low. These observations indicate that exposure to styrene at about 50 mg/m3 may induce reversible neuraesthenic symptoms. Even the relatively low Swedish standard (110 mg/m3 = 25 ppm) may, therefore, need revising.

Adult↗
PubMed1989

Human epidermal Langerhans' cells are sensitive to rapid cooling by ethyl chloride.

Topical anesthesia with ethyl chloride spraying generates some remarkable reactive events in the human Langerhans' cell (LC) system. Many LC retract their dendrites and a considerable number move to the innermost layers of the epidermis within 15 minutes. This rapid motility supports the view that the interstices between cells in living epidermis are large. The LC cytomembrane is very susceptible to cold shock which causes the cytomembrane to superimpose upon itself forming abnormally shaped Birbeck granules. This process may consume too much of the cytomembrane to be compatible with cell survival.

Biopsy↗