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Biomedical subjects

A Isaksson

Publications and source records attributed to A Isaksson.

At least 127 records · Page 7Linked to original sources
PubMed1981

A possible explanation for the occurrence of increased beta-hexosaminidase activity in pregnancy serum.

The activities of the lysosomal enzymes beta-hexosaminidase, beta-glucuronidase, and beta-galactosidase were confirmed to be elevated in serum from pregnant women. The increased activity of beta-hexosaminidase and beta-glucuronidase showed the same changes in the isoenzyme pattern as found in serum from patients with some liver affections. In the light of recent findings, the increased activity of beta-hexosaminidase (and some other lysosomal enzymes) in pregnancy and liver disease might depend upon the non-parenchymal liver cells not being able properly to clear these enzymes from the blood.

Acid Phosphatase↗
PubMed1981

beta-Hexosaminidase in serum from patients with cirrhosis and cholestasis.

THe enzyme activity level of beta-hexosaminidase (beta-N-acetylglucosaminidase, EC 3.2.1.30; 2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase) in serum from patients with different forms of cirrhosis and cholestasis was found to be elevated. A comparison is also made with routine liver parameters. In the light of recent findings it seems probable that the increased level depends upon depressed clearance of this enzyme by the non-parenchymal cells in the liver.

Adult↗
PubMed1981

beta-Hexosaminidase level in serum from patients with viral hepatitis as a measure of reticuloendothelial function.

The lysosomal enzyme beta-hexosaminidase was elevated in different forms of hepatitis. The enzyme level was correlated to the aminotransferases in the acute stage of hepatitis A and B. In hepatitis B there was also a correlation to ALP and bilirubin. In chronic hepatitis B a significant correlation was found only to ALAT. The elevated beta-hexosaminidase levels are attributed to defective non-parenchymal liver cell function in hepatitis.

Adult↗
PubMed1980

Beta-hexosaminidase, leucine aminopeptidase, cystidyl aminopeptidase, hepatic enzymes and bilirubin in serum of chronic alcoholics with acute ethanol intoxication.

beta-Hexosaminidase, leucine aminopeptidase, cystidyl aminopeptidase and routine liver parameters are studied in serum of chronic alcoholics with acute ethanol intoxication. The frequencies of pathological serum levels of the routine measurements made are in relatively good agreement with earlier reports. Serum leucine aminopeptidase and cystidyl aminopeptidase did now show any significant aberration in alcoholic liver disease. They correlated well with each other, and gamma-glutamyltransferase. beta-Hexosaminidase activity in serum was increased in almost all patients at the time of admission. All the patients showed decreasing values during the observation period.

Alcoholic Intoxication↗
PubMed1980

Rhythmic changes in estriol excretion during pregnancy.

Different biologic rhythms with effect on one and the same parameter may cause a complicated signal pattern in which no regularity can be visually identified. In this study an autocorrelation function approach, well established in the interpretation of electroencephalograms, was shown to be applicable also in the interpretation of processes with few points of observation. This technique, used on the excretion of estriol in urine, reveals several rhythms with wavelengths between 6 and 72 hours. Interference between these signals may explain the irregular visual appearance of plots of subsequent estriol determinations and the considerable rise and fall of urinary estriol excretion during pregnancy. The presence of two independent sources of the rhythms is suggested. It is concluded that the complicated and individual rhythmic changes in urinary excretion of estriol results in a low diagnostic specificity for fetoplacental malfunction of this component.

Circadian Rhythm↗
PubMed1980

Acid hydrolases in serum from patients with lysosomal disorders.

The activity of acid hydrolases was studied in serum from patients with mucolipidosis (II and III) and other lysosomal disorders. In mucolipidosis II and III all hydrolases examined except alpha-glucosidase, beta-glucosidase and acid phosphatase were greatly increased. High values for beta-galactosidase were seen in mucopolysaccharidosis types I and II, Gaucher's disease, juvenile amaurotic idiocy and metachromatic leucodystrophy. N-Acetyl-beta-glucosaminidase activity was high in mucopolysaccharidosis types I, II, III and Gaucher's disease. The activity of beta-glucuronidase was increased in mucopolysaccharidosis types I, II and III, Gaucher's disease, juvenile amaurotic idiocy and metachromatic leucodystrophy. Acid phosphatase had increased activity only in Gaucher's disease. In several lysosomal storage disorders no increased values could be found. It is suggested that high values in serum from patients with lysosomal storage disorders (not including mucolipidosis II and III) may depend upon liver cell damage, which disturbs the clearing of acid hydrolases from serum.

Acid Phosphatase↗
PubMed1980

Exposure to organic solvents. A cross-sectional epidemiologic investigation on occupationally exposed care and industrial spray painters with special reference to the nervous system.

In the present epidemiologic study 80 car or industrial spray painters with long-term low level exposure to organic solvents were examined and compared with two matched reference groups of nonexposed industrial workers (80 persons in each group). The aim of the study was to investigate the possible effects of the solvent exposure on health. The investigation included psychiatric interviews, psychometric tests, neurological, neurophysiological and ophthalmologic examinations, and computed tomography of the brain. The painters' previous and present exposure was carefully assessed by interviews and on-the-job measurements both at modern places of work and in a reconstructed model of a workshop from 1955. On the basis of the psychiatric interviews the psychiatric symptoms were rated according to a specially designed scale of 46 different items, graded in seven steps of increasing severity. The psychological performance was assessed by a battery of 18 tests. The neurological and neurophysiological examinations comprised visual evoked responses (VER), electroencephalography (EEG), and computerized EEG analysis (SPA) for the central nervous system and electroneurography (ENeG), the estimation of vibration sense thresholds, and a quantified neurological examination for the peripheral nervous system. The ophthamologic examination concentrated on the condition of the lens. Statistically significant differences between the exposed individuals and referents were found for psychiatric items indicative of a slight cerebral lesion (ie, a neurasthenic syndrome). The psychometric tests revealed statistically significant differences between the groups with respect to reaction time, manual dexterity, perceptual speed, and short-term memory. No differences were found with respect to performance on verbal, spatial, and reasoning tests. Significant differences between the groups were also found for the majority of the neurophysiological parameters measuring peripheral nerve functions, the most pronounced occurring in the long, sensory fibers. Moreover EEG and VER showed some differences between the groups, as did the results of the ophthalmologic examination and the computed tomography. Finally, it should be emphasized that the exposure levels, as measured at modern places of work and in the reconstructed workshop from 1955, were found to be considerably lower than the valid threshold limit values in Sweden.

Brain↗
PubMed1978

Long-term exposure to jet fuel. II. A cross-sectional epidemiologic investigation on occupationally exposed industrial workers with special reference to the nervous system.

Thirty jet fuel exposed workers selected according to exposure criteria and thirty nonexposed controls from a jet motor factory were examined, with special reference to the nervous system, by occupational hygiene physicians, psychiatrists, psychologists, and neurophysiologists. The controls and the exposed subjects were matched with respect to age, employment duration, and education. Among the exposed subjects the mean exposure duration was 17 years, and 300 mg/m3 was calculated as a rough time-weighted average exposure level. The investigation revealed significant differences between the exposed and nonexposed groups for (a) incidence and prevalence of psychiatric symptoms, (b) psychological tests with the load on attention and sensorimotor speed and (c) electroencephalograms. When the control group was selected, it was ensured that the two groups were essentially equivalent except for exposure to jet fuel. It is concluded, therefore, that the differences found between the groups are probably related to exposure to jet fuel.

Adult↗
PubMed1976

Visible and non-visible EEG changes demonstrated by spectral parameter analysis.

A change of the heart rate in patients with complete AV-block and externally controllable cardiac pace-makers was earlier shown to influence cerebral function, as measured by psychological tests. To determine whether this influence manifests itself in the EEG, 9 patients aged 43-83 years were examined, all having complete AV-block and externally controllable pace-makers. Their EEGs were recorded at different heart rates between 40 and 100/min at rest and during a mental arithmatic test. The EEG record was evaluated visually and analysed by means of Spectral Parameter Analysis (SPA), introduced by Zetterberg (1969). The changes in the spectral parameters in relation to the heart rates were analysed statistically, In several cases significant changes appeared but the interindividual variations were large. Certain typical patterns could, however, be observed and their importance as a measure of cerebral function due to changes in the cerebral blood flow are discussed. These EEG changes revealed through SPA did not correspond to any visually observable changes in the EEG records. Differences in the spectral parameters between rest and test situations were analysed. Some of the differences found could easily be observed by visual inspection of the EEG. The advantage with SPA was that the changes could be described both qualitatively and quantitavely because SPA separates the spectral properties of the signals into components corresponding to well-known components of the EEG signal.

Adult↗
PubMed1975

An EEG simulator-a means of objective clinical interpretation of EEG.

In 1969 Zetterberg presented a method for describing the spectral properties of an EEG signal, starting from the assumption that the signal is essentially stationary during the analysis epoch. The method involves determination of the parameters for a model consisting of a lenear filter with the ability to produce a signal with the same spectral properties as the EEG signal. Zetterberg and Ahlin described in 1975 an analogue simulator based on this model theory. With this simulator it is possible to reproduce practically all types of stationary, as well as a number of non-stationary, EEG signals. We have used this simulator to demonstrate in an illustrative manner the relation between the properties of a signal in the spectral domain and in the time domain. We have also endeavoured to anser the question: if one starts from the frequency spectrum, what does the EEG signal corresponding to this spectrum look like? We also draw attention to the usefulness of the simulator in connection with training and as an instrument for testing computer and other systems of EEG analysis.

Computers↗
PubMed1975

Visual evaluation and computer analysis of the EEG--a comparison.

Spectral parameter analysis (SPA) of the EEG provides a description of the distribution of spectral power in the EEG signal in the form of a rational spectrum with not more than 8 parameters. The spectrum is divided into 1-3 components described by frequency and power parameters: bandwidth (delta), peak frequency (f) and power (G). These spectral parameters are determined with the aid of a computer. The character of the EEG signal decides whether 1, 2 or 3 components (delta, alpha, beta) are needed to describe the spectrum. To test its practical value, the result of SPA was compared with that of ordinary visual evaluation of the EEG of 65 healthy men between the ages of 18 and 22 years. 20 sec sections from different leads were analysed and evaluated visually. Each EEG section was graded according to the amount of visually evaluated slow activity (VESA). To investigate the relation between the degree of VESA and the SPA result, statistical calculations (variance and regression analyses) were carried out, both for single SPA parameters and for the general type of spectrum, i.e., the number of components composing the spectrum. The SPA results from sections with artefacts were treated separately and compared statistically with results from artefact-free sections. In records with a high degree of VESA, all the leads analysed showed a tendency to have a power spectrum of low order, i.e., with few components. In most leads there was a linear regression between the degree of VESA and the bandwidth and power of the delta and alpha components. In several cases this relation was an expression of a significant linear change of the SPA parameter as a function of the degree of VESA. On the other hand the parameters of the beta component showed no relation to the degree of VESA. It was found that muscle activity could influence any spectral component thereby providing it with a strongly increased bandwidth. This is probably due to the fact that muscle activity resembles white noise in this particular frequency range. Low frequency artefacts affected only the delta component the bandwidth of which was significantly smaller than in the artefact-free sections.

Adolescent↗