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G Karlsson

Publications and source records attributed to G Karlsson.

At least 19 recordsLinked to original sources
PubMed1992

Blockade of GABAB receptors accelerates amygdala kindling development.

The aim of this study was to investigate the putative role of GABAB receptors in the development of amygdala kindling in rats. The effects of the GABAB blocker CGP 35348 and the GABAB agonist baclofen on the progressive development of behavioural seizure symptoms (stages 1-5 classified by Racine) and duration of after-discharges (AD) were studied. CGP 35348 at a dose of 300 mg/kg i.p., which blocks central GABAB receptors, moderately but consistently accelerated the development of behavioural seizure symptoms. CGP 35348 had no marked effect on the duration of ADs corresponding to the different seizure stages. L-baclofen (6 mg/kg i.p.) had a dual effect on kindling development. It retarded the development of the behavioural symptoms, but increased the duration of AD. In conclusion, the results suggest that synaptically-released GABA activated GABAB receptors and thereby exerted a depressant effect on kindling development.

Amygdala↗
PubMed1992

Mast cells and eosinophils in the allergic mucosal response to allergen challenge: changes in distribution and signs of activation in relation to symptoms.

An allergen challenge was performed in 10 asymptomatic patients with strictly seasonal allergic rhinitis. For comparison; seven nonallergic subjects were challenged with allergen, and seven allergic patients were challenged with diluent. Cell samples, obtained with use of a brush technique to recover cells from within the epithelium and nasal lavage to collect cells from the epithelial surface, and symptom scores were taken before challenge and at 2-hour intervals during 12 hours. The cell suspensions were cytocentrifuged onto object slides for light microscopy. Histamine was determined in the cell pellets. In brush samples from the allergic patients challenged with allergen, eosinophils, expressed as a percentage of the total granulocytes, increased from 4.3% +/- 2.7% (mean +/- SEM) to 10.3% +/- 3.8% (p < 0.05) 4 hours after challenge. This level was maintained for up to 12 hours. A similar increase was noted in the lavage specimens 2, 6, and 8 hours after the challenge. In the brush samples the proportion of eosinophils containing two or more cytoplasmic vacuoles, taken as a sign of activation, increased from 20% to 72% (p < 0.05) 8 hours after provocation. In brush samples from the allergic patients challenged with allergen, the numbers of metachromatic cells increased to a maximum of eightfold at 10 hours. In the lavage specimens, no metachromatic cells were observed before provocation, but they progressively increased in number 2 to 12 hours after provocation. Cell pellet histamine content decreased temporarily 2 to 4 hours after challenge (p < 0.05) in brush samples from allergen-challenged allergic patients. The local metachromatic cell density before challenge, as reflected in the brush specimens, correlated with nasal congestion, sneezing, and the degree of eosinophilia.

Adult↗
PubMed1992

GABAB receptors in various in vitro and in vivo models of epilepsy: a study with the GABAB receptor blocker CGP 35348.

The effect of the GABAB receptor blocker CGP 35348 on epileptic processes in vitro and in vivo was studied. In hippocampal slices of the rat maintained in vitro, CGP 35348 (100 microM) induced a moderate increase in the frequency of extracellularly recorded spontaneous epileptiform burst discharges induced in CA3 by penicillin (1.2 mM), bicuculline (5 microM) and low Mg(2+) (0.1 mM). This effect was observed in 50-75% of the slices. A similar but less consistent increase was also observed in CA1 in bicuculline and low Mg2+. Data obtained by intracellular recordings from CA1 pyramidal cells in the presence of bicuculline (10 microM) demonstrated that CGP 35348 (100 microM) increased the duration of the paroxysmal depolarization underlying an evoked epileptiform burst and reduced the early component of the after hyperpolarization which followed the burst. In mice pretreated with isoniazid, CGP 35348 (300 mg/kg, i.p.) significantly increased the number of convulsing mice. However, convulsions induced by submaximal doses of pentylenetetrazol, picrotoxin or strychnine were not facilitated by CGP 35348. We conclude that GABAB receptors appear to exert a suppressant effect on various kinds of epileptiform discharges of hippocampal neurons in vitro. In vivo, however, the role of GABAB receptors in regulating convulsions is less prominent since only isoniazid-induced convulsions were facilitated by GABAB receptor blockade.

Animals↗
PubMed1992

The relationship between stressful working conditions and high alcohol consumption and severe alcohol problems in an urban general population.

The relationship between 15 measures of stressful working conditions and high alcohol consumption (35 g 100% ethanol per day or more for men and 25 g or more for women) was studied, using cross-sectional data from a general population survey of 1344 males and 1494 females; the ages 25-64 years in metropolitan Stockholm in 1984. In a longitudinal component of the study, hospitalization and mortality with alcohol-related diagnosis was assessed during 1984-90, and also the association between previous experience of unemployment and high alcohol consumption. Some of the associations, expressed as age-adjusted odds ratios, were positive and some were negative when high alcohol consumption was the endpoint, but there was a clear variation by sex and social class. Generally the positive associations were stronger among male non-manual employees. Among males, there was a clear association between stressful working conditions and subsequent risk of severe medical alcohol-related problems, but the precision of the estimates was low due to low number of cases. The odds ratio was 6.18 (95% confidence interval 1.86, 20.61) for twisted working positions and 6.74 (95% confidence interval 1.67, 27.19). Previous unemployment among males was associated with increased risk for high alcohol consumption, with an odds ratio of 5.71 (95% CI 1.39, 15.97) among those who had been unemployed more than once, and 1.67 (95% CI 0.76, 3.64) among those who had been unemployed once during the previous 5 years. Those and other increased odds ratios were lower when subjects with an alcohol diagnosis at inpatient care during 1980-84 were excluded in the analyses. On the whole, our findings are not conclusive. The strong, but imprecise associations between stressful working conditions and severe alcohol problems, are however challenging, and warrants further studies, preferably with longitudinal design and repeated measurements of both working condition and alcohol habits.

Adult↗
PubMed1991

Clinical efficacy of budesonide in the treatment of eczematous external otitis.

Sixty patients with mild to moderate forms of eczematous otitis externa were treated with budesonide and placebo in a double-blind controlled study using parallel groups. Each treatment period was preceded by otomicroscopic examination and thorough cleaning of the ear canal. The symptoms and signs were assessed with a score system ranging from 0 (no symptoms/signs) to 3 (severe symptoms/signs). Budesonide treatment was associated with a reduction in severity of all symptoms recorded and a marked improvement in erythema, swelling and discharge. Mechanical cleaning of the ear canal and placebo was not a sufficient treatment for this group of patients.

Administration, Topical↗
PubMed1991

IgG subclass deficiency with or without IgA deficiency.

IgG subclass deficiency (IgGSD) is difficult to define since reference materials vary between laboratories and the clinically relevant cut off levels for the various subclasses are not well known. The diagnosis of IgGSD should be based on more than one determination since the levels vary, due to various factors such as infections, operations, etc. There is a relation between IgGSD and occurrence of frequent infections, but at the same time even total lack of a subclass can be seen in healthy individuals. Infections in the upper and lower respiratory tract predominate. Gm allotypes influence IgG subclass levels. Most IgGSD patients are homozygous in the Gm system. Immunocytes producing IgG3 in the nasal mucosa correlate with serum IgG3 levels, whereas rectal IgG1 producing cells relate to serum IgG1 levels. This may reflect differences in antigen and/or mitogen exposure at the two mucosal sites. IgG2SD is the predominant form of IgGSD among children, whereas after puberty IgG3SD is most common. At the same age period there is a switch in sex distribution from three boys/one girl to one male/three females. Various abnormalities in B and T lymphocyte numbers and function are often found. In a double blind crossover study of Ig prophylaxis over 2 years in 43 IgGSD adult patients a significant decrease in the number of days with infections was seen both in the whole group and among the IgG1 deficient. Days with bronchial constriction were also significantly decreased among the 22 patients who had asthma as well. Acute bronchitis became significantly less frequent in the IgG3 deficient patients during Ig prophylaxis. This was seen in those under the lower range of 0.41 g/liter of Oxelius' early normal material, although many recent reference materials suggest 0.14-0.15 g/liter of IgG3 as the cut off. In a group of 25 consecutive patients with IgGSD + IgA deficiency recurrent respiratory infections were the major problem and lung function impairment was found in 12, and bronchiectasies in 5. Still many individuals with this combined deficiency have been reported to be healthy, again illustrating our limited understanding of these conditions.

Disease↗
PubMed1991

Isotype distribution of mucosal IgG-producing cells in patients with various IgG subclass deficiencies.

The subclass distribution of IgG-producing immunocytes was examined by immunohistochemistry in nasal and rectal mucosa of infection-prone patients with untreated IgG subclass deficiencies. Biopsy specimens from the two sites were obtained in 18 clinically and serologically well-characterized adult subjects; only a nasal or rectal sample was available from nine similar patients. Chronic lung disease was common in the patient groups with selective serum IgG1 deficiency and combined IgG1 and IgG3 deficiency, whereas the other categories of patients had mainly upper airway and other mild infections. Serum IgG2 or IgG3 deficiency was usually expressed also at the cellular level in rectal mucosa, and the proportion of rectal IgG1 cells was significantly correlated with the IgG1 level (r = 0.90, P less than 0.001). Likewise, there tended to be a decreased expression of the actual subclass at the cellular level in nasal mucosa of patients with serum IgG1 or IgG2 deficiency. Conversely, the median nasal proportion of IgG3 cells was remarkably unaffected by a deficiency of this subclass in serum and rectal mucosa. Interestingly, these patients rather tended to have raised IgG3 and reduced IgG2 cell proportions in their nasal mucosa, although this apparent local IgG3 compensation was nevertheless strongly correlated with the serum IgG3 level (r = 0.87, P less than 0.002). These disparities may reflect different antigenic and mitogenic exposure of the two tissue sites; for example, a persistent protein bombardment of the nasal mucosa that could conceivably override locally a B cell maturation defect. The possible clinical consequences of such variable mucosal expression of IgG subclass deficiencies remain to be studied.

Adult↗
PubMed1991

Macrophages on the nasal mucosal surface in provoked and naturally occurring allergic rhinitis.

Macrophages are the most common cell type residing in the lumen of the lower airways. However, very little is known about the presence and putative pathogenic implications of macrophages in the upper airways. Using specific immunohistochemical techniques, the presence of and changes in macrophage density were studied before and after allergen exposure in the laboratory and during natural allergen exposure of subjects with seasonal allergic rhinitis. The monoclonal antibody EBM 11 combined with the alkaline phosphatase-anti-alkaline phosphatase-technique was applied on cytospin-prepared slides. In the challenge experiment, 0.5 +/- 0.2% (mean +/- SEM; n = 10) of the total cell number were positive for the EBM 11 marker before challenge, thereby not differing from the controls (0.2 +/- 0.2%; mean +/- SEM; n = 3). Local allergen challenge induced an increase of these cells to a peak of 1.3 +/- 0.4% after 4 h (p less than 0.05). During seasonal exposure there was also a similar increase, from 0.7 +/- 0.2 to 1.3 +/- 0.3% (p less than 0.05; n = 11) in placebo-treated patients and from 0.7 +/- 0.2 to 1.6 +/- 0.4% (p less than 0.05; n = 11) in patients treated with topical glucocorticoids. There was, however, no direct relationship between nasal symptoms and number of macrophages present on the mucosal surface. The study indicates that macrophages are involved in the inflammatory processes of allergic rhinitis.

Adolescent↗
PubMed1990

CGP 35348: a centrally active blocker of GABAB receptors.

The biochemical, electrophysiological and pharmacological properties of the new GABAB receptor blocker CGP 35348 are described. In a variety of receptor binding assays CGP 35348 showed affinity for the GABAB receptor only. CGP 35348 had an IC50 of 34 microM at the GABAB receptor. The compound antagonized (100, 300, 1000 microM) the potentiating effect of L-baclofen on noradrenaline-induced stimulation of adenylate cyclase in rat cortex slices. In electrophysiological studies CGP 35348 (10, 100 microM) antagonized the effect of L-baclofen in the isolated rat spinal cord. In the hippocampal slice preparation CGP 35348 (10, 30, 100 microM) blocked the membrane hyperpolarization induced by D/L-baclofen (10 microM) and the late inhibitory postsynaptic potential. CGP 35348 appeared to be 10-30 times more potent than the GABAB receptor blocker phaclofen. Ionophoretic and behavioural experiments showed that GABAB receptors in the brain were blocked after i.p. administration of CGP 35348. This compound may be of considerable value in elucidating the roles of brain GABAB receptors.

Adenylyl Cyclase Inhibitors↗
PubMed1990

Characterization of the binding epitope of the monoclonal antibody DMAb-1 to ganglioside GM2.

Several derivatives of ganglioside GM2 were synthesized for mapping of the binding epitope of a monoclonal antibody raised against this ganglioside. The GM2 ganglioside was modified in both the hydrophobic and the hydrophobilic part of the molecule. The synthesized derivatives were characterized with fast atom bombardment mass spectrometry (FAB-MS). Affinity of the monoclonal antibody for the GM2 derivatives was determined by enzyme-linked immunosorbent assay (ELISA) on microtitre plates or by TLC immunostaining. Modifying the GM2 sialic acid by deacetylation or blocking of the carboxyl moiety abolished the binding to the monoclonal antibody while the cleaving of the glycol group on the sialic acid tail led to a 70% reduced binding affinity. Removal of the fatty acid (lyso-GM2) eliminated the binding to the antibody. GM2 derivatives with fatty acid moieties of 8 carbon atoms or less showed almost no reactivity. GM2 with saturated fatty acids 16:0, 18:0 and 20:0 had binding affinity similar to natural GM2, while the 24:0 fatty acid had only half the binding affinity. The results demonstrate the importance of ganglioside fatty acid composition with regard to ligand binding between the monoclonal antibody and its specific ganglioside antigen. Thus, caution must be shown in the application of immunaffinity methods with monoclonal antibodies for the quantitative determination of glycosphingolipids from different tissues.

Antibodies, Monoclonal↗
PubMed1990

The effects of baclofen and two GABAB-receptor antagonists on long-term potentiation.

The aim of the present study was to investigate whether activation or inhibition of GABAB receptors in hippocampal slices of rats has an impact on the synaptic plasticity in the CA1 area. Long-term potentiation (LTP) was induced by tetanic stimulation of the Schaffer collateral/commissural fiber tract and the responses of CA1 pyramidal neurons were recorded extracellularly. The increase in population spike amplitude after tetanic stimulation was taken as a measure of LTP. The selective GABAB receptor blockers phaclofen (1 mM) and CGP 35,348 (100 microM) facilitated the induction of LTP. Although baclofen (1 microM) reduced the population spike amplitude, it did not affect LTP. If, however, the stimulation voltage was increased to compensate for the baclofen-induced decline in population spike amplitude, LTP was facilitated. Under these conditions the induction of LTP was accompanied by the appearance of additional population spikes. In conclusion, GABAB receptors appear to exert a modulatory action on LTP.

Animals↗
PubMed1990

Ear discharge after insertion of transmyringeal tubes.

The peroperative bacteriology and cytology of the middle ear have been studied in 103 ears in 65 children operated on due to longstanding secretory otitis media. Within one month postoperatively, 12 ears (12%) showed signs of infection with discharge from the tube. Ten out of these 12 ears showed peroperative growth of Hemophilus influenzae, Branhamella catarrhalis, pneumococci or staphylococci in the middle ear effusions, a significant difference compared to ears without postoperative discharge. The peroperative cytological evaluation of the middle ear effusions from 10 out of the 12 patients with postoperative ear discharge showed presence of phagocytes as a sign of infection. It is concluded that pre-existing bacteria in the middle ear effusion of patients with longstanding secretory otitis media might increase the risk of postoperative infection within the first month after insertion of transmyringeal tubes.

Bacteria↗
PubMed1990

Cost-benefit evaluation of dental implants.

The growing evidence of the efficacy and effectiveness of dental implants calls for economic evaluations to determine the economic efficiency of this technology for different indications. Such studies must be integrated with the clinical evaluations in order to produce the relevant data. In most cases, dental implants will produce a better outcome than the best alternative technology, but this improvement will only come at greater cost. Cost-benefit evaluations of dental implants must therefore address the difficult task of assessing the value of the improvement in oral health.

Cost-Benefit Analysis↗
PubMed1990

Cytological and bacteriological aspects of secretory otitis media.

Bacteriological and cytological examinations were performed on 105 middle ear secretions from 66 children with middle ear effusion (MEE) of more than 3 months' duration. The secretions were searched for granulocytes and the activity of these cells was judged by their capacity for random locomotion and their ability to reduce nitroblue tetrazolium. The functional characteristics of the granulocytes were compared with the bacteriological findings on cultures from MEE. Bacteria commonly regarded as pathogens in middle ear infections (Hemophilus influenzae, Branhamella catarrhalis or Streptococcus pneumoniae) were found in 25% of the secretions. Granulocytes with activity or lacking activity, virtually dead, were found in all secretions where these bacteria were isolated. In secretions where bacteria commonly regarded as commensals, mainly staphylococci, were isolated, about two thirds of the secretions showed phagocytes with or without activity. No relation between bacterial growth and the functional state of the granulocytes was observed. In contrast, no phagocytes were found in over 60% of MEE lacking bacterial growth. These findings suggest a role for bacteria in the development and maintenance of secretory otitis media.

Child↗
PubMed1990

Luxation of the elbow complicated by proximal radio-ulnar translocation.

Luxation of the elbow complicated by proximal radio-ulnar translocation is a rare entity. The clue to diagnosis is the reversed position of the bones of the proximal forearm. In the a.p. projection the radial head articulates with the trochlea and the ulna with the capitellum. This unexpected anatomic relationship is easily overlooked. Delayed reduction may result in permanent impairment of elbow motility. Our experience with three recent cases is presented.

Child↗