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Biomedical subjects

I Karlsson

Publications and source records attributed to I Karlsson.

At least 91 records · Page 5Linked to original sources
PubMed1988

Laboratory- and species-specific interpretive breakpoints for disk diffusion tests of chloramphenicol susceptibility of Haemophilus influenzae.

A total of 601 clinical isolates of Haemophilus influenzae isolated in six different regions of Sweden were tested for chloramphenicol susceptibility by using agar dilution MIC determinations and disk diffusion tests. For seven strains MICs were 4 micrograms/ml or higher, and for one strain the MIC was 2 micrograms/ml. All eight strains produced chloramphenicol acetyltransferase. For the remaining 593 strains, MICs were less than or equal to 1 microgram/ml, and the MICs for 50% and 90% of the strains were both 0.5 microgram/ml. Disk diffusion tests carried out by using revised interpretive criteria introduced in 1984 by the Swedish Reference Group for Antibiotics correctly identified the 593 strains as susceptible and the 8 strains as resistant. Quality assessments were performed in 29 clinical microbiology laboratories. The revised criteria for chloramphenicol disk diffusion testing gave rise to false resistance results in some laboratories. The interpretive accuracy improved when the interlaboratory variation was compensated for by using adjusted breakpoints. Such revision was possible through peak correction, single-strain regression analysis, and standard curve regression analysis. Peak-corrected breakpoints improved the accuracy from an overall incidence of false-resistant isolates of 4.4% to 2.3%. Single-strain regression analysis and standard curve regression analysis provided laboratory- and species-specific breakpoints which reduced false resistance rates of 0.14% and 0%, respectively.

Chloramphenicol↗
PubMed1987

Antibodies in cerebrospinal fluid of some Alzheimer disease patients recognize cholinergic neurons in the rat central nervous system.

The etiology of Alzheimer disease is unclear. However, immunological aberrations have been suggested to be critical factors in the pathogenesis of this neurodegenerative disease. This study was carried out to investigate if cerebrospinal fluid (CSF) from Alzheimer disease patients contains antibodies that recognize specific neuronal populations in the rat central nervous system. The results indicate that in a subgroup of patients this is indeed the case. The antibodies reported in this study have the following properties: (i) they recognize neuronal populations and components in the medial septum and spinal motor neurons in rats perfused with a mixture that fixes small neurotransmitter molecules; (ii) adsorption of the patient CSF with staphylococcal protein A-Sepharose and using a polyclonal antiserum against human IgG3 indicates that the immunocytochemical reaction in these brain regions is mainly due to the subclass IgG3; and (iii) the CSF immunocytochemical reaction is blocked by preincubation of the sections with a rabbit anti-acetylcholine antiserum. These results provide evidence that antibodies in the CSF of some, but not all, Alzheimer disease patients recognize acetylcholine-like epitopes in cholinergic neurons in the rat central nervous system.

Acetylcholine↗
PubMed1987

Monoamines and their metabolites in cerebrospinal fluid of patients with senile dementia of Alzheimer type using high performance liquid chromatography and gas chromatography-mass spectrometry.

Monoamines and their main metabolites were measured using HPLC-EC in the cerebrospinal fluid from age-matched elderly in-patients affected with senile dementia of Alzheimer type and chronic schizophrenia. Determination of the monoamine metabolites MHPG, HVA and 5-HIAA was also performed by means of gas chromatography-mass spectrometry. Significant differences were obtained with the two methods, the largest deviation being found for HVA, which was 15% higher in the HPLC method than in the GC-MS method, despite the correlation between the results of two measurements being consistent for all the three metabolites. The degrees of motor, intellectual and emotional deterioration were assessed using GBS rating scale. The results show a clear psychobehavioral and neurochemical differentiation of the two patient groups. HVA and 5-HIAA levels were significantly lower in SDAT patients, and showed a trend toward negative correlation with the degree of dementia.

Aged↗
PubMed1986

Alterations in cerebrospinal fluid concentrations of somatostatinlike immunoreactivity in neuropsychiatric disorders.

The concentration of somatostatinlike immunoreactivity in cerebrospinal fluid (CSF) from normal, healthy volunteers (n = 10) and patients with DSM-III diagnoses of major depression (n = 17), schizophrenia (n = 11), or dementia (n = 29) was measured by a sensitive and specific radioimmunoassay. Statistically significant decreases in CSF concentrations of somatostatinlike immunoreactivity were seen in all three patient populations when compared with controls. These findings confirm previous reports of decreased concentrations of somatostatinlike immunoreactivity in the CSF of patients with depression and dementia and extend this observation to patients with schizophrenia as well. These findings are concordant with the view that reductions in somatostatinlike immunoreactivity concentrations are associated with diseases in which cognitive function is disturbed.

Adult↗
PubMed1985

The use of 3H-gamma-aminobutyric acid for transport studies with isolated nerve-terminals from rat brain.

Isolated synaptosomes were used to study the problem of net accumulation of neurotransmitters. The time-course and the kinetics of exogenous and endogenous GABA transport were studied by liquid-scintillation counting and HPLC-amino acid analysis respectively. Different pools of GABA were suggested by a 6-fold difference in tissue-to-medium-ratio of endogenous vs. exogenous GABA. Net accumulation, exchange and net efflux of GABA was found to be a function of the GABA concentration in the incubation medium. The Kms for net accumulation and for 3H-GABA accumulation were 2.68 +/- 1.16 and 6.19 +/- 1.26 microM respectively, whereas the Vmaxs were 5.9 +/- 4.9 and 134 +/- 13 pmol/mg w.w. min respectively. This means that the transport studies which use exogenous substances (e.g. 3H-GABA) considerably overestimate the transport by overlooking the magnitude of the counter transport.

4-Aminobutyrate Transaminase↗
PubMed1984

Elevated concentrations of CSF corticotropin-releasing factor-like immunoreactivity in depressed patients.

The possibility that hypersecretion of corticotropin-releasing factor (CRF) contributes to the hyperactivity of the hypothalamo-pituitary-adrenal axis observed in patients with major depression was investigated by measuring the concentration of this peptide in cerebrospinal fluid of normal healthy volunteers and in drug-free patients with DSM-III diagnoses of major depression, schizophrenia, or dementia. When compared to the controls and the other diagnostic groups, the patients with major depression showed significantly increased cerebrospinal fluid concentrations of CRF-like immunoreactivity; in 11 of the 23 depressed patients this immunoreactivity was greater than the highest value in the normal controls. These findings are concordant with the hypothesis that CRF hypersecretion is, at least in part, responsible for the hyperactivity of the hypothalamo-pituitary-adrenal axis characteristic of major depression.

Adult↗
PubMed1984

Frequency and type distribution of pneumococcal strains in the Stockholm region with resistance or reduced susceptibility to antibiotics.

Of 191 consecutive clinical isolates of Streptococcus pneumoniae tested for antibiotic susceptibility with the agar dilution technique 87% were fully sensitive to all of 11 antimicrobial agents examined. 90% of the strains were inhibited by 0.016 micrograms/ml of benzylpenicillin, by 0.032 micrograms/ml of ampicillin, cefuroxime, erythromycin, clindamycin or rifampicin, by 0.13 micrograms/ml of cephalothin, oxacillin or doxycycline, by 4.0 micrograms/ml of chloramphenicol and by 8.0 micrograms/ml of cotrimoxazole. 18 strains exhibited a reduced susceptibility to one (11 strains) or more (7 strains) of erythromycin, doxycycline, chloramphenicol and cotrimoxazole. One of these strains also showed a reduced susceptibility to all 5 examined beta-lactam antibiotics, as did another 4 strains. Two of these 5 strains were isolated from small children recently adopted from 2 Asian countries. Cotrimoxazole-resistant strains were significantly more often isolated from children 1 yr of age or less than from older patients. All strains were fully sensitive to clindamycin and rifampicin. The existence of pneumococcal strains with resistance or reduced susceptibility to antibiotics commonly used for treatment of pneumococcal infections is important to bear in mind and necessitates antibiotic susceptibility testing of strains isolated from patients with severe infections.

Adolescent↗
PubMed1983

Alaproclate: a pharmacokinetic and biochemical study in patients with dementia of Alzheimer type.

Alaproclate, a specific inhibitor of neuronal serotonin re-uptake, was given to 12 patients with dementia of Alzheimer type. The drug was rapidly absorbed and an elimination half-life of 7.1 +/- 0.9 h (+/- SD, n = 8) was calculated. Plasma protein binding for alaproclate was 82 +/- 1%. Two weeks of repeated administration produced plasma concentrations of alaproclate similar to those predicted from a single dose. The pharmacological effect of the drug was demonstrated by an inhibition of serotonin uptake in the patients' platelets and a reduction of the serotonin concentration in blood. Global rating of clinical efficacy showed a positive effect of alaproclate in five of the patients, mainly regarding emotional functions.

Aged↗
PubMed1983

Dexamethasone suppression test and serum prolactin in dementia disorders.

The dexamethasone suppression test (DST) was performed on 21 patients with dementia of the Alzheimer type (DAT), 11 patients with multi-infarct dementia (MI) and 14 healthy controls. Twelve of the DAT patients and eight of the MI patients showed abnormal lack of suppression, compared with just one member of the control group. Abnormal DST was related to dementia as such and not to age or depression, or to levels of CSF monoamine metabolites. Basal serum prolactin concentrations were not increased.

Aged↗
PubMed1982

Studies on duration of a late recovery period after chronic abuse of ethanol. A cross-sectional study of biochemical and psychiatric indicators.

A cross-sectional study on patients with different abstinence time was performed to describe long-time biochemical and psychiatric changes due to withdrawal from heavy alcohol abuse. Physical, neurological, psychiatric and biochemical parameters were measured in 70 patients with a withdrawal period ranging from 2-90 days. The various parameters changed over time in different manners. Fatigability, reduced sleep, reduced sexual interest, apparent sadness, hostility and global ratings of abstinence improved significantly with the duration of the recovery period. Symptoms related to brain hyperexcitability such as fatigability, inner tension, insomnia and pains persisted for approximately 5 weeks. Of the biochemical parameters, the transaminases were normal in patients with more than 10 days of abstinence, while the levels of gamma-glutamyltransferase and HDL-cholesterol remained high for longer periods. The essential fatty acid status, measured by the fatty acid composition of serum lecithin, appeared to be normal only in patients with long recovery time. MAO in platelets was significantly lower than in the controls. The highest values were seen in the early recovery phase, which may indicate a temporary increase. Since polyunsaturated fatty acids are important constituents of synaptic membranes and since platelet MAO may reflect brain MAO, we consider these co-existing findings important in the interpretation of the psychiatric symptoms. The study demonstrated the existence of a subacute withdrawal syndrome lasting for 4-6 weeks.

Adult↗
PubMed1982

Synergism between aminoglycosides and cephalosporins with antipseudomonal activity: interaction index and killing curve method.

Combinations of gentamicin with cefotaxime, moxalactam, and ceftazidime were tested against 43 bacterial strains, most of them blood isolates. With an interaction index of less than or equal to 0.5 as borderline, synergism was demonstrated against 30 to 40% of the strains by the fractional inhibitory concentration index and against 50 to 70% by the fractional bactericidal concentration index. The reproducibility of the index was within +/- 0.2 for two-thirds of 40 repetitive assays and within +/- 0.4 to 0.5 for all of these assays. Similar results were obtained when netilmicin was substituted for gentamicin. The killing curve system for studying antibiotic synergism was standardized to give results comparable to those obtained with the interaction index. This was achieved when one-half of a previously determined minimum bactericidal concentration was used for single drugs and the amount of antibiotic was at least halved again when drugs were used in combination. An initial bacterial concentration of 10(5) to 10(6) colony-forming units per ml is recommended. Given these conditions, synergism could be defined as a 2-log 10 or more decrease in viable count given by both drugs together, as compared with the more active of the pair after 24 h. Prediction of killing curve results could then be obtained with the fractional bactericidal concentration index. When cephalosporins and gentamicin were combined from the start, the beta-lactam antibiotics were less susceptible to inactivation, as demonstrated in time-killing assays. If one of the antibiotics were added after 24 h, synergism was not demonstrable. The results indicate that the new cephalosporins may be advantageously combined with aminoglycosides.

Aminoglycosides↗
PubMed1982

Technical note--test instructions for the technical testing of mono-functional myoelectrically-controlled prosthetic hands. A proposal.

To get an acceptable standard of prostheses and orthoses in Sweden, the Swedish Institute for the Handicapped is testing this group of aids. One important part of the work is to draw up test instructions. In response to a request from the Swedish Institute for the Handicapped, the Laboratory of Rehabilitation Engineering at the University Hospital of Linköping in Sweden, has suggested instructions for the technical testing of monofunctional myoelectrically controlled prosthetic inspection and control factors which are important for the function of the prosthetic hand.

Amputation, Surgical↗
PubMed1979

Forebrain fatty acid composition during development in protein-calorie and essential fatty acid deficiencies in the rat.

Rats were fed three different dietary levels of essential fatty acids (EFA), 3.0, 0.75 and 0.1 cal%, representing normal, subnormal and severely deficient dietary intakes. From the animals kept on these diets, with a protein content of 16 cal%, 3-month-old females were randomly selected to be fed diets with only 6 cal% protein but with unchanged amounts of EFA. The rats were then mated, and the effects of the diets were studied in the forebrains of their offspring. The growth and the fatty acid patterns of the ethanolamine phosphoglyceride and total phosphoglyceride fractions were studied during the first 60 days of life. Addition of protein-calorie deficiency to rats severely undernourished in EFA mitigated the biochemical signs of EFA deficiency. In EPG the developmental pattern with a decrease of 20:4 (n-6) and an increase of 22:6 (n-3) was retarded between 11 and 21 days of age in the protein-calorie deficient groups suggesting a delay in the maturation of the forebrain.

Aging↗