Biomedical subjects

L Lindström

Publications and source records attributed to L Lindström.

At least 73 records · Page 4Linked to original sources

PubMed1985

Haptoglobin and transferrin types in schizophrenia.

Haptoglobin and transferrin types were studied in schizophrenic patients and controls. In the haptoglobin system a significant departure from the Hardy-Weinberg equilibrium with an excess of heterozygotes was found among the patients (p less than 0.01). The distribution of haptoglobin types in the schizophrenic patients was significantly different from that in the controls. The distribution of transferrin types showed a good agreement with the Hardy-Weinberg equilibrium. There was no significant difference between patients and controls with respect to transferrin types.

Gene Frequency↗

PubMed1985

Alpha 1-antitrypsin types in schizophrenia.

The gene and phenotype frequencies of alpha 1-antitrypsin were studied in patients with (49) and without (92) a family history of schizophrenia. A significant difference with respect to phenotype (p less than 0.05) and gene (p less than 0.025) frequencies was found between the two groups of patients. Among patients with a family history of schizophrenia there was a significant increase of the M1 gene and a decrease of the M2 gene. There were no significant differences between schizophrenic patients and controls.

Gene Frequency↗

PubMed1985

Complement factor C4 in schizophrenia.

The complement factor C4 was studied in 165 schizophrenic patients and in 330 controls. A highly significant increase in the frequency of C4B deficiency (BQO) was found among the schizophrenic patients compared with controls (p less than 0.0005).

Complement C4↗

PubMed1985

C3 and C6 complement types in schizophrenia.

C3 and C6 complement types were studied in schizophrenic patients and controls. The distributions of the three common C3 types (F, FS and S) among the patients was significantly different from that in the controls (p less than 0.005) and the frequency of the C3F gene was significantly increased (p less than 0.0005) among the patients. There were no significant differences in C6 gene or phenotype frequencies between patient and controls.

Complement C3↗

PubMed1984

Cortical evoked potentials obtained after stimulation of the lower urinary tract.

Cortical evoked potentials following stimulation of the lower urinary tract have been recorded in humans. Of 26 patients investigated 9 had no urinary signs or symptoms except genuine stress incontinence, while the remaining 17 had various neurogenic bladder disorders. Monopolar and bipolar stimulation of the bladder and urethra was performed using conventional and newly designed suction-type electrodes. While no cortical evoked potentials could be obtained from patients with complete transverse spinal cord lesions polyphasic cortical evoked potentials (N45, P60, N80 and P100 msec.) were recorded in response to monopolar bladder stimulation in all patients with stress incontinence. Following bipolar stimulation a response with lower amplitude and with latencies slightly divergent could be recorded. This response is assumed to be evoked only from bladder afferent nerves, while the monopolar response could include activity from adjacent structures. The most consistent pattern was recorded at the Cz site. Cortical evoked potentials following stimulation of the urethra were more difficult to evoke but they resembled those obtained after bipolar stimulation of the bladder. The method, when fully developed, may be helpful in the clinical investigation of patients affected by various neurogenic disorders of the lower urinary tract. So far, in our limited series a delayed response at P2 has been observed in patients with uninhibited neurogenic bladders.

Adult↗

PubMed1984

Automatic selection of uncontaminated electromyogram as applied to respiratory muscle fatigue.

An automatic procedure for detecting artifacts in the electromyogram (EMG) has been developed and applied to a study of respiratory muscle fatigue. Signal segments are characterized by a set of features, the normal variations of which have been estimated in a training session. From the features are calculated a classification variable, which expresses the degree of deviation from normal conditions. A deviation larger than a certain threshold value designates a segment as disturbed. The study deals with the choice of features, the selection of a suitable segment length, and the determination of an optimal classification threshold. The four features chosen include measures of amplitude symmetry, extreme excursions in the signal tracing, the signal-to-noise ratio, and the shape of the EMG power spectrum. Recordings from three subjects were used for the evaluation of the method. The results indicate that a segment length of 250 ms is appropriate. Accepting a 10% rate of false detections, the average rate of missed detections was 2.2%.

Diaphragm↗

PubMed1983

Masseter muscle fatigue in man objectively quantified by analysis of myoelectric signals.

Localized muscle fatigue in the masseter muscle was studied with a method based on power spectrum analysis of myoelectric signals. Under the influence of fatiguing contractions, a gradual shift of the spectral curve occurred; the rate of change was taken as a measure of the development of fatigue. The fatigue was dependent on the bite force. The existence of a threshold value of force, below which significant myoelectric fatigue changes do not develop, was shown.

Adult↗

PubMed1983

Comparative and scaling aspects of heart and body weights with reference to blood supply of cardiac fibers.

Relative heart weight (RHW) differs in vertebrates with the ratio 1:20 between extremes (bottom bound fishes--Pleuronectidae--and birds). When plotting heart weight (HW) against body weight (BW) one obtains channels which contain not only vertebrates of the same classes (poikilotherms, small and big mammals and birds) but also animals belonging to different classes: tuna fish data are located in the "small mammalian channel" together with data of large tropical snakes while large mammals (upwards 4000 g) belong to the "bird channel". Reasons for such groupings are not clear and physical activity seems not to be the only reason. When comparing active and non active vertebrates one finds that the RHW is as a rule greater in physically more active poikilotherms and homoiotherms. The RHW is also higher in wild than in domesticated forms the differences appearing after weaning (wild vs laboratory rat). In spongy type of myocardium the growth of cardiac fibers results in restriction of the blood flow through lacunae and the contact between endothelial cells lining growing strands of musculature probably provokes formation of capillaries. The appearance of mixed type of myocardium (outer compact and inner spongy compartments) is not bound to the water to land transition since it occurs also in some fishes; it does not occur or is rare in amphibia and is frequent in reptiles. The compact outer layer comprises a different proportion of the cardiac wall volume (5-73%). Metabolic differences were described between cardiac cells in compact and spongy compartments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1983

Rotation of synergistic activity during isometric jaw closing muscle contraction in man.

5 healthy subjects were studied during 10-15 min of isometric jaw elevator contraction above fatigue threshold level. Bite force was measured between upper and lower front teeth and electromyographic (EMG) activity recorded from the right temporal and masseter muscles. Of the two muscles only the masseter was active at the start of the test and usually during the whole test. When the test was repeated, however, great relief from the pain in the fatigued masseter was sometimes experienced and the temporalis took over the load. All subjects experienced this "switch" phenomenon after a varying number of tests, one of them already during his first test. The mechanism seemed to be completely out of voluntary control and showed facilitation at repeated tests.

Electromyography↗

PubMed1982

Cortical evoked potentials following stimulation of the urinary bladder in man.

Techniques are described for recording evoked potentials in humans in response to stimulation of the urinary bladder. Twenty patients with various disorders of their urinary function were investigated. Evoked cortical potentials following stimulation of the urinary bladder could be recorded from all patients except subjects with complete transverse spinal cord lesions. The response was most evident at the central site (Cz) and had its most prominent peaks at 45, 65, 82 and 102 msec. This technique may become a useful diagnostic tool in the study of neurogenic bladder dysfunctions.

Aged↗

PubMed1982

The measurement of serum cortisol by a solid-phase chemiluminescence immunoassay.

A solid-phase chemiluminescent immunoassay (LIA) for the determination of cortisol in serum specimens has been developed. The separation of the cortisol onto the solid-phase distinguishes this particular assay from other chemiluminescence immunoassays. The method can be used without prior extraction. Cortisol molecules were made chemiluminescent by conjugation to aminobutylethyl-isoluminol. The detection limit of the label in the chemiluminescent reaction was 0.1 pmol. The LIA was compared with a RIA for cortisol in 36 serum specimens and the correlation between the assays was good (r = 0.97). The time course of the chemiluminescent reaction is fast and a 20's integration time gave reproducible results. The peak light intensities were not reliable.

Humans↗

PubMed1981