| 61. |
- Niklasson, Urban, 1955-
(författare)
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Spectral analysis of the heart rate variability : a methodological study
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Heart rate and other cardiovascular variables are not steady but fluctuate over time. The evolution of computer technology the last 2 decades has made detailed analysis of the fluctuations possible and has focused the attention to the information content of the variability.Autonomic nervous influence on the heart can be assessed by measuring the heart rate variability from R-R intervals in the electrocardiogram. Applications have been developed in many fields where the pathophysiological features of the patients include autonomic dysfunction.This thesis is based on clinical studies and model studies compared with results from healthy volunteers. Two patient groups, with familial amyloidosis and with myotonic dystrophy, were evaluated using simple indexes of heart rate variability. Signs of autonomic dysfunction which is a dominant clinical feature in familial amyloidosis with polyneuropathy was confirmed by abnormal heart rate variability indexes. In myotonic dystrophy heart rate variability was normal but recumbent and standing plasma catecholamines were elevated. Reassessment of the heart rate variability with spectral analysis confirmed the results.The integral pulse frequency modulation (IPFM) model can be used as a simple analogy of the interface between autonomic activity and the cardiac pacemaker. Computer simulations using the IPFM model revealed marked differences in the estimated modulating variability depending on whether the intervals between simulated beats or the frequency of beats was analyzed. Comparison with data from healthy volunteers indicated that the IPFM model was valid and that heart rate should be preferred instead of R-R intervals for variability measurements.Beat-by-beat heart rate can be viewed as an irregular sample of the underlying autonomic activity. Spectral analysis of simulated heart rate variability data using the IPFM model showed attenuation of high frequency variability with decreasing mean heart rate and with increasing variability mean frequency. Application of these results on data from healthy volunteers suggest that the effects can be significant in actual variability measurements.Cholinergic blockade resulted in reduced heart rate variability at all spectral frequencies. Adrenergic beta-blockade reduced high-frequency variability in standing position indicating that high-frequency variability might partly be sympathetically mediated.
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| 62. |
- Nilsson, Bengt E, 1949, et al.
(författare)
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In vivo regulation of mucosal transport of H+ and HCO3- in the feline gall bladder.
- 1993
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Ingår i: Acta physiologica Scandinavica. - 0001-6772. ; 148:4, s. 403-11
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Tidskriftsartikel (refereegranskat)abstract
- In the gall bladder of a fasting subject, a decline in the pH of the contents occurs due to secretion of H+ from the mucosa. In this study in anaesthetized cats, the gall bladder lumen was perfused with a bicarbonate buffer bubbled with 4% CO2 in air. During basal conditions, the PCO2 always rose while the pH and [HCO3-] fell in the buffer when passing through the gall bladder lumen, indicating a continuous secretion of H+ by the mucosa. This H+ secretion was enhanced by stimulation of the respective sympathetic nerves and was blocked by intraluminal amiloride. Intravenous infusion of vasoactive intestinal peptide (VIP) raised the pH and [HCO3-] in the buffer during the passage through the gall bladder lumen, indicating a secretion of bicarbonate from the mucosa. In view of the presence of sympathetic and VIP immunoreactive nerve fibres in the gall bladder wall and VIP receptors on the luminal epithelial cells, the study demonstrates that there are functional grounds for physiological variations in the secretion of H+ and HCO3- by the gall bladder mucosa. These variations may be important for the solubility of calcium salts in the gall bladder contents.
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| 63. |
- Olovsson, Matts, 1958-, et al.
(författare)
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Biotin labelling of chicken antibodies and their subsequent use in ELISA and immunohistochemistry
- 1993
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Ingår i: Comparative Immunology, Microbiology & Infectious Diseases. - 0147-9571 .- 1878-1667. ; 16:2, s. 145-152
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Tidskriftsartikel (refereegranskat)abstract
- Avian antibodies have many advantages to mammalian antibodies due to the phylogenetic differences between birds and mammals, resulting in an increased sensitivity and a decreased background in many immunological assays. Since the avidin-biotin system is an efficient detection system for antibodies with a high sensitivity, we wanted to investigate the activity and unspecific binding of optimally biotin labelled chicken antibodies in ELISA and immunohistochemistry. We report on the conditions for biotinylation of chicken antibodies and that optimally biotinylated antibodies show a high activity and a low background in both ELISA and immunohistochemistry.
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| 64. |
- Revesz, Peter, et al.
(författare)
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Measurement of spleen size using gamma camera scintigraphy in essential thrombocythaemia.
- 1993
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Ingår i: European journal of haematology. - 0902-4441. ; 51:3, s. 141-3
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Tidskriftsartikel (refereegranskat)abstract
- By using gamma camera imaging the spleen size was determined in 33 consecutive patients with essential thrombocythaemia (ET) and in 33 consecutive patients with reactive thrombocytosis (RT). All ET patients were newly diagnosed and had not received myelosuppressive treatment prior to study; they all fulfilled the criteria for ET as established by the Polycythemia Vera Study Group. In both posterior and lateral projections, the spleen area in the group of ET patients was significantly larger than in the RT patients. The present study has shown that 39% of ET patients at diagnosis have splenic enlargement. Evaluation of spleen size is therefore a useful diagnostic test in patients presenting with unexplained thrombocytosis.
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| 65. |
- Slunga, Lisbeth, 1958-
(författare)
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Serum lipoprotein(a) in relation to ischemic heart disease and associated risk factors
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lipoprotein(a) (Lp(a)) consists of an LDL-like particle and the specific protein apo(a), which is very similar to plasminogen. Apo(a) contains repeated kringle structures and a serine protease domain, which cannot be activated by t-PA. Lp(a) is considered to be a predictor for atherosclerotic disease. It has been found incorporated in atherosclerotic plaques and inhibits in vitro fibrinolysis.Lp(a) was determined in 1527 randomly selected individuals participating in the Northern Sweden WHO-MONICA project. A weak but significant relation between Lp(a) and increasing age was found. Menopausal status was the strongest independent predictor of Lp(a) level in women. Fibrinogen was independently related to Lp(a) in both sexes. Only a minor fraction of Lp(a) variance could be explained for in a multiple regression model, which is in agreement with the contention that Lp(a) is highly genetically determined.Lp(a) was determined in 1571 patients investigated with coronary angiography because of suspected severe coronary artery disease (CAD). Patients with proven CAD at elective angiography had significantly higher Lp(a) than patients without significant CAD or healthy controls. Lp(a) was found to be an independent discriminator of CAD in both sexes.HLA-DR genotype 13 or 17 was found more frequently in 30 male patients with angiographic CAD at young age (< 50 years) than in 30 age matched controls. These genotypes were common in patients with high Lp(a) levels, which indicates that Lp(a) may be related to immunological processes.The reaction of Lp(a) was investigated in 32 patients with acute myocardial infarction (AMI). Lp(a) increased during the first week, but the response was comparatively weak. Individual Lp(a) responses were heterogeneous and no correlations to infarct size or changes in the acute phase proteins were found.In a randomized cross-over study on 36 hypercholesterolaemic patients treated with simvastatin/placebo during 12+12 weeks Lp(a) did not change significantly, but patients with high Lp(a) levels at baseline tended to develop further increased Lp(a).To conclude, Lp(a) was found to be an independent predictor of angiographic CAD in both men and women. Lp(a) levels are primarily genetically determined and only a small fraction of Lp(a) variance could be explained by other factors in this study. Lp(a) may be related to HLA DR types and immunological processes involved in atherosclerotic disease. Lp(a) increased slightly during the first week of AMI, but was not related to changes in the acute-phase proteins. The effective LDL-lowering agent simvastatin did not influence Lp(a) significantly.
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| 66. |
- Sonesson, Björn, et al.
(författare)
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Compliance and diameter in the human abdominal aorta--the influence of age and sex
- 1993
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Ingår i: European Journal of Vascular Surgery. - 0950-821X. ; 7:6, s. 690-697
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES. Females develop cardiovascular diseases and abdominal aortic aneurysms later in life than males. In this study we investigated the diameter and compliance of the distal abdominal aorta in healthy females of varying ages. The results were compared with those obtained previously from healthy males in order to assess potential sex-related differences in the aging process of the abdominal aorta. METHODS. An ultrasound phase-locked echo-tracking system was used to determine differences in diameter and pulsatile diameter change of the distal abdominal aorta in 69 Caucasian females from 4 to 74 years. Pressure strain elastic modulus (Ep) and stiffness (beta) were calculated from diameter, pulsatile diameter change and blood pressure obtained by the auscultatory method. Compliance was defined as the inverse of Ep and beta. The pressure dependence of Ep and beta was evaluated in 10 females with intraarterial blood pressure measurement at rest and during isometric exercise. RESULTS. The diameter of the distal abdominal aorta increased not only in the period between the ages of 5 and 25 years, but also by about 24% between 25 and 70 years (p < 0.0001). From about the age of 25 years the diameter was smaller in females than in males (p < 0.01). Ep and beta increased nearly linearly with advancing age in females from 0.18 x 10(5) to 1.17 x 10(5) N/m2 (Ep) and from 1.85 to 8.51 (beta). In males the increase in Ep and beta was greater and exponential in nature (p < 0.001). Ep but not beta increased significantly during blood pressure increase (p < 0.05). Stiffness (beta) may therefore be a more useful index of arterial compliance than Ep. CONCLUSIONS. This investigation demonstrates age and sex-related differences in diameter and compliance in the normal human abdominal aorta and implies that degenerative changes appear later in females than in males.
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| 67. |
- Sundgren, P, et al.
(författare)
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Elevation of the larynx on normal and abnormal cineradiogram
- 1993
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Ingår i: British Journal of Radiology. - : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 66:789, s. 72-768
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Tidskriftsartikel (refereegranskat)abstract
- The relationship between bolus volume (2.5, 5, 10 and 20 ml) and larynx elevation during swallowing was assessed in 10 non-dysphagic and 10 dysphagic individuals without pharyngeal dysfunction. Laryngeal elevation in different types of pharyngeal dysfunction was assessed in 60 non-dysphagic and 75 dysphagic patients. All subjects were examined with liquid barium and cineradiography at 50 frames/s. The laryngeal elevation was measured at the moment when the bolus reached the level of the valleculae and at maximum elevation. Elevation of the larynx, both the initial and maximal, was not influenced by sex, age or presence of dysphagia. Elevation of the larynx at the moment when the bolus reached the valleculae, when expressed in per cent of maximum elevation, was lower with 10 and 20 ml bolus volumes compared with 2.5 ml bolus volume (p < 0.05) in the 10 dysphagic individuals. Pharyngeal dysfunction was associated with significantly lower initial elevation of the larynx, at the moment when the bolus reached the level of the valleculae, although the maximal laryngeal elevation was normal. Initial elevation was 30% lower (p = 0.03) in patients with aspiration of bolus material into the trachea, 22% lower (p = 0.007) in those with defective closure of the laryngeal vestibule without aspiration and 16% lower (p = 0.06) in those with incoordination of the cricopharyngeal muscle compared with patients without dysfunction.
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| 68. |
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| 69. |
- Tufveson, G, et al.
(författare)
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Organ transplantation in Göteborg with particular reference to kidney transplantation.
- 1993
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Ingår i: Clinical transplants. - 0890-9016. ; , s. 243-51
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Tidskriftsartikel (refereegranskat)abstract
- The limiting factor in organ transplantation is the availability of organs. Continuing work to improve the public's willingness to donate organs and inspire hospital staff to collaborate in organ procurement is essential. Identification of patients who will not benefit from transplantation can also increase the availability of organs. Grafts may also be saved by identification and appropriate treatment of recurrent renal disease. Xenotransplantation may eventually solve the problem, but major obstacles remain. Meanwhile, work in this field may help to clarify mechanisms of rejection. New immunosuppressive drugs may improve graft survival and reduce the incidence and progression of chronic rejection.
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| 70. |
- Ulfvin, A, et al.
(författare)
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Expression of glycolipid blood group antigens in single human kidneys: change in antigen expression of rejected ABO incompatible kidney grafts.
- 1993
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Ingår i: Kidney international. - 0085-2538. ; 44:6, s. 1289-97
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Tidskriftsartikel (refereegranskat)abstract
- Total neutral glycolipid fractions were separated into molecular species on thin-layer chromatography plates and detected by immunostaining with monoclonal anti-blood group antibodies. Blood group A antigens based on type 1, 2, 3 and 4 carbohydrate core saccharides were present in kidneys of A1 and A1B individuals. Blood group A2 individuals expressed only small amounts of A antigen compared to A1 individuals especially of the type 3 and 4 compounds. Kidneys from non-secretor individuals contained less A antigen compared to secretor individuals, and in both groups a variation in the antigen expression between single individuals was noted. Blood group A type 2 and 3 (which is an extension of A type 2) antigens were present both as basic 6 and 9 sugar structures as well as extended saccharide chains migrating in the 8 to 11 sugar interval. In contrast, the type 1 chain based A and Lewis antigens were only present as their basic 5 to 7 sugar chains, and no elongated structures were found. Four cases of A2 kidneys initially transplanted into O recipients and removed after 5, 12, 21 days and 4 years, respectively, were also analyzed. Two of these kidneys, originating from the same donor, showed a difference in A antigen expression. The kidney functioning for four years (lost due to chronic rejection) completely lacked X antigen with five sugar residues (present in all other individuals) and contained a large amount of A antigens.(ABSTRACT TRUNCATED AT 250 WORDS)
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