Search PubMed⌕ Search

Biomedical subjects

J Andersson

Publications and source records attributed to J Andersson.

352 records · Page 20Linked to original sources

Rapid lymphocytic recognition of histoincompatibility. Changes of the deoxyribonucleoprotein complex in mixed cultures of allogeneic human lymphocytes.

The mechanism of growth stimulation in allogeneic lymphocytes mixed in vitro was studied at the cell level by means of cytophotometric techniques. A pronounced increase in fluorescence intensity of fixed and acridine orange (AO) stained lymphocytes was observed as soon as after 1-3 hr in mixed culture. No increase in the amount of DNA took place during this time. The higher fluorescence intensity was due to an increased accessibility of AO binding sites in the deoxyribonucleoprotein (DNP) complex, most probably as a result of weakened bonds between the DNA and the protein moiety in the DNP complex. Similar DNP changes have been found in other systems of growth stimulation and may be one prerequisite for later induction of cellular synthetic processes. Increased AO binding only occurred when the lymphocyte donors were incompatible at the major histocompatibility locus (HL-A); there was no change in AO binding in cases of HL-A identity. The AO binding reaction probably reflects a specific recognition of HL-A antigens, whereas other antigenic discrepancies between the individuals do not seem to cause an analogous response.

Acridines↗

Haemophilus influenzae and Streptococcus pyogenes group A challenge induce a Th1 type of cytokine response in cells obtained from tonsillar hypertrophy and recurrent tonsillitis.

We have previously shown that tonsil tissue both from children with tonsillar hypertrophy and recurrent tonsillitis is colonized and invaded by Haemophilus influenzae and Streptococcus pyogenes group A. In order to evaluate if these bacteria are involved in the immunopathogenesis of these two conditions, tonsillar cells from both groups were stimulated in vitro with intact, heat-inactivated H. influenzae or S. pyogenes A. The immunoreactivity was evaluated by assessing the induction of cytokine production (IL-1 alpha, IL-1 beta, TNF-alpha, IL-6, IL-8, IL-2, IFN-gamma, IL-4, TNF-beta and IL-10), which was detected at the single-cell level. All cytokines studied except IL-4 were induced in both groups after stimulation with H. influenzae or S. pyogenes A. The dominating cytokines were IL-1 beta, IFN-gamma and TNF-beta. No major differences in the cytokine pattern or number of cytokine-producing cells were noticed between the two patient cohorts after H. influenzae stimulation. Activation by S. pyogenes A bacteria gave rise to higher frequencies of IFN-gamma- and TNF-beta-synthesizing cells in the recurrent tonsillitis group. The incidence of CD4-, CD8-positive T cells and CD40-positive B cells was comparable between the two groups while the MAC-387-positive macrophages were significantly higher in the recurrent tonsillitis groups. In conclusion, a Th1 type of cytokine response was found in both groups following stimulation with H. influenzae or S. pyogenes A.

Antigens, Bacterial↗

Frontal dysfunction and frontal cortical synapse loss in alcoholism--the main cause of alcohol dementia?

Alcoholics often develop personality and behavioural changes, social and personal neglect, confabulation, lack of insight, empathy and emotional control. Such symptoms would increase the risk of engagement in and exposure to acts of violence and criminal activities carrying a risk of physical damage including head trauma and violent death. This was the case in at least 4 of the studied cases. A structural basis for such frontal lobe symptoms was looked for in a forensic material of 18 alcoholics, compared with an age-matched control group with regard to liver disease, brain changes of the Wernicke-Korsakoff type and cortical, especially frontal cortical changes. The salient finding was a consistent pattern of synapse loss in the superior laminae of the frontal cortical area 10 of Brodman in heavy drinkers, not related to liver disease or possible previous mental disease. The synapse loss is more likely related to alcohol, possibly mediated through vitamin B deficiency. Brain stem lesions as a source of additional symptoms cannot be dismissed. This pattern of synapse loss in alcoholism has not been described previously. The cortical changes are closely similar to those found in frontotemporal dementia, and seem to be a plausible main cause of the alcoholic frontal symptomatology and alcoholic dementia.

Adult↗

Imaging of nicotinic and muscarinic receptors in Alzheimer's disease: effect of tacrine treatment.

Functional imaging techniques offer new possibilities for further understanding of changes in functional correlates of structural and biological changes in dementia disorders like Alzheimer's disease (AD). Regional disturbances in glucose metabolism and cerebral blood flow are known to occur in AD brains and probably roughly correlate to changes in neurotransmitter activities. A proper estimate would be to visualize the neuroreceptors themselves. In this study the cholinergic nicotinic and muscarinic receptors were studied in brain by positron emission tomography (PET). The rate constant k2* (s) (-)11C-nicotine was significantly higher (+43%) in temporal cortex of AD patients compared to controls (p < 0.017) indicating a lower binding of 11C-nicotine in AD brains compared to controls. Treatment with the cholinesterase inhibitor tacrine (80 mg daily) during 3 months to AD patients resulted in a mean plasma concentration of 7.7 +/- 0.8 ng/ml and a corresponding inhibition of the cholinesterase activity in plasma by 34 +/- 5%. A significantly lower k2* (increased binding) for 11C-nicotine binding (-15%; p < 0.006) was obtained in the temporal cortex after 3 months of treatment compared to prior treatment. The muscarinic antagonist 11C-benztropine was used to visualize muscarinic receptors and the binding capacity of 11C-benztropine (KR) was found to be decreased in the temporal cortex after 3 months of tacrine treatment.

Aged↗