| 1. |
- Damm, S., et al.
(författare)
-
Wall motion abnormalities in male elite orienteers are aggravated by exercise
- 1999
-
Ingår i: Clinical Physiology. - : Wiley. - 0144-5979 .- 1365-2281. ; 19:2, s. 121-126
-
Tidskriftsartikel (refereegranskat)abstract
- During the period 1979-92, 16 (15 men and one woman) sudden unexpected cardiac deaths occurred among young Swedish orienteers. This finding indicated a sharp increase in the death rate of orienteers, and necropsy demonstrated that myocarditis was a common histopathological finding. Therefore, an extensive non-invasive cardiac investigation was performed. A total of 59 male élite orienteers (mean age 23 years) and 36 cross-country skiers and middle-distance runners (mean age 22 years), serving as controls, were examined by both echocardiography at rest and radionuclide ventriculography at rest and during exercise. Wall motion abnormalities were found in eight orienteers using echocardiography. The purpose of this study was to examine whether the group of orienteers with wall motion abnormalities found using echocardiography had a smaller increase in ejection fraction from rest to exercise using radionuclide ventriculography than the rest of the orienteers and the controls, indicating an aggravation of the wall motion abnormalities during exercise. There were no significant differences in the ejection fraction at rest between the groups. In the orienteers with wall motion abnormalities (group 1), 62% (five out of eight) had less than a 0.05 unit increase in left ventricular ejection fraction compared with 27% (14 out of 51) of the remaining orienteers (group 2) and 19% (7 out of 36) of the controls (group 3). A comparison of athletes in group 1 with those in groups 2 and 3 combined revealed a statistically significant difference (P < 0.05). The divergent response in left ventricular ejection fraction during exercise suggests an aggravation of the wall motion abnormalities with exercise. Both the echocardiographic and the radionuclide ventriculographic findings indicate that the orienteers in group 1 had concealed left ventricular damage.
|
|
| 2. |
- Collingwood, T N, et al.
(författare)
-
A natural transactivation mutation in the thyroid hormone beta receptor: impaired interaction with putative transcriptional mediators.
- 1997
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424. ; 94:1, s. 248-53
-
Tidskriftsartikel (refereegranskat)abstract
- The syndrome of resistance to thyroid hormone is characterized by elevated serum free thyroid hormones, failure to suppress pituitary thyrotropin secretion, and variable peripheral refractoriness to hormone action. Here we describe a novel leucine to valine mutation in codon 454 (L454V) of the thyroid hormone beta receptor (TR beta) in this disorder, resulting in a mutant receptor with unusual functional properties. Although the mutant protein binds ligand comparably to wild-type receptor and forms homo- and heterodimers on direct repeat, everted repeat, or palindromic thyroid response elements, its ability to activate transcription via these elements is markedly impaired. The hydrophobic leucine residue lies within an amphipathic alpha-helix at the carboxyl terminus of TR beta and the position of the homologous residue in the crystal structure of TR alpha indicates that its side chain is solvent-exposed and might interact with other proteins. We find that two putative transcriptional mediators (RIP140 and SRC-1) exhibit hormone-dependent association with wild-type TR. In comparison, the interaction of this natural mutant (L454V) and artificial mutants (L454A, E457A) with RIP140 and SRC-1 is markedly reduced. Furthermore, coexpression of SRC-1 is able to restore the transcriptional activity of the L454V mutant receptor, indicating that the interaction of this residue with accessory proteins is critical for transcriptional activation. Finally, the occurrence of the L454V mutation in resistance to thyroid hormone, together with impaired negative regulation of the thyroid-stimulating hormone alpha promoter by this mutant, suggests that the amphipathic alpha-helix also mediates hormone-dependent transcriptional inhibition, perhaps via interaction with these or other accessory factors.
|
|
| 3. |
|
|
| 4. |
- Funegård, Ulrika, et al.
(författare)
-
Rat salivary gland function after fractionated irradiation.
- 1997
-
Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 36:2, s. 191-198
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate longitudinal effects of fractionated irradiation, with various total doses, on salivary gland function in the rat. Female Sprague-Dawley rats were irradiated with 4, 5, 6, 7 or 8 Gy per day on five consecutive days. Irradiation was given to the head and neck region. Whole saliva was collected before and 2, 15 and 26 weeks after irradiation. In general the effects of irradiation on salivary gland function were found to be related to dose and time after exposure. Secretion rates were significantly decreased two weeks after irradiation with doses of 30 Gy or higher, after 15 weeks with 25 Gy or higher, and after 26 weeks with 20 Gy or higher. Response patterns to irradiation differed between the salivary constituents. Thus, the conclusions from this study are that early and late effects display different patterns and that the model used to study variations in salivary gland function after fractionated irradiation must be adjusted to the question addressed.
|
|
| 5. |
|
|
| 6. |
- Henriksen, Egil, et al.
(författare)
-
An echocardiographic study of right and left ventricular adaptation to physical exercise in elite female orienteers
- 1999
-
Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 20:4, s. 309-316
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A considerable body of echocardiographic studies has described how athletic training induces morphological adaptation of the left ventricle in male endurance athletes, but only a few studies have described left ventricular adaptation in female endurance athletes. In contrast to changes in the left ventricle far less attention has been directed towards right ventricular changes due to extensive physical exercise. The purpose of this study was to obtain normal values and to determine if there are any differences in right and left ventricular cavity and wall dimensions between female orienteers and females with a mainly sedentary lifestyle. METHODS: Echocardiography was performed in 42 highly trained elite female orienteers and 32 healthy female students with a predominantly sedentary lifestyle. The 74 females had no history of cardiac disease, a normal electrocardiogram and showed no echocardiographic abnormalities. M-mode and two-dimensional measurements of the right and left ventricular cavity and wall were obtained in elite orienteers and sedentary females. For the right ventricle and wall, multiple cross-sections were used and measurements were obtained from the right ventricular inflow and outflow tract. RESULTS: The left ventricular end-diastolic cavity dimension and the left ventricular wall thickness were significantly greater in the athletes compared with the sedentary controls. The right ventricular inflow tract measurements were all significantly greater in the orienteers compared with the controls but the right ventricular outflow tract measurements were comparable in the study groups. The right ventricular wall thickness, calculated as the mean of three different wall measurements was an average of 13% greater in the athletes compared with the sedentary controls. CONCLUSION: This study suggests symmetrical cardiac enlargement with a concomitant increase in both the right and left ventricular wall, probably reflecting the increased haemodynamic loading in the female athletes.
|
|
| 7. |
- Henriksen, Egil, et al.
(författare)
-
Echocardiographic right and left ventricular measurements in male elite endurance athletes
- 1996
-
Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 17:7, s. 1121-1128
-
Tidskriftsartikel (refereegranskat)abstract
- Echocardiography was used to assess normal values in the right and left ventricular cavity and wall in 127 male elite endurance athletes. M-mode and two dimensional measurements of left ventricle and left and right atria were also obtained. All subjects were high-performance orienteers, cross-country skiers and middle-distance runners. They all had a normal electrocardiogram at rest and no echocardiographic evidence of heart disease. With the use of multiple right ventricular cross-sections and two-dimensional measurements, we found a significantly greater right ventricular inflow tract and right and left atrial measurements in endurance athletes compared with earlier studies of normal, active subjects. The right ventricular free wall was slightly thicker than reported in normal active subjects but the differences were small. Left ventricular diastolic diameter was consistent with previous reports of endurance athletes. Of the 127 subjects, 13% had left ventricular wall thickness above 13 mm but none of the athletes had wall thickness above 15 mm. These data suggest that cardiac enlargement occurs symmetrically in both right and left cavities, probably reflecting increased haemodynamic loading, a mechanism by which athletes sustain a high cardiac output during exercise.
|
|
| 8. |
- Nilsson, T, et al.
(författare)
-
The relations of microalbuminuria to ambulatory blood pressure and myocardial wall thickness in a population.
- 1998
-
Ingår i: Journal of internal medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 244:1, s. 55-9
-
Tidskriftsartikel (refereegranskat)abstract
- To examine the relationship between microalbuminuria (20-200 microg min(-1)) and 24 h ambulatory blood pressure and heart wall thickness, in a representative population sample of men and women aged 56-65 years.Every second individual aged 56-65 years (n=488) in the district, was invited for a health examination, which included determination of urinary albumin and creatinine (overnight sample). The highest and lowest decentile of urinary albumin/creatinine ratio were compared.The district of the Primary Health Care and Research Centre of Mölnlycke, Sweden.After excluding 2 individuals with a urinary albumin excretion exceeding 200 microg min(-1). 26 subjects (group 1) could be compared with 27 subjects in the lowest decentile (group 2).Comparison between the determinations of the ambulatory blood pressure and echocardiographic variables in the two groups.Group 1 had significantly higher 24 h ambulatory blood pressure, and heart septum and posterior wall thickness as well as significantly higher fasting blood glucose and serum triglyceride concentrations. The differences in blood pressure (P < 0.05) but not heart wall thickness remained significant (P<0.05) after excluding subjects with hypertension, angina pectoris, treated diabetes mellitus, and/or history of heart or cerebrovascular disease. When excluding individuals with both treated and untreated diabetes mellitus, fasting blood glucose concentration was higher in group 1. The waist-hip ratio, weight and body mass index did not differ between the groups.The findings indicate that microalbuminuria is related to signs of cardiovascular and metabolic influence and therefore could be a valuable tool for grading the risk of later cardiovascular morbidity.
|
|
| 9. |
- Wesslén, Lars, et al.
(författare)
-
An increase in sudden unexpected cardiac deaths among young Swedish orienteers during 1979-1992
- 1996
-
Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 17:6, s. 902-910
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Sixteen cases of sudden unexpected cardiac death, 15 males and one female, are known to have occurred among young Swedish orienteers from 1979 to 1992, of which seven cases occurred between 1989 and 1992. This is considered to be indicative of an increased death rate. RESULTS: Histopathological evaluation showed myocarditis in a higher than expected proportion of cases. In one such case, which we studied before the sudden unexpected death occurred, the victim had suffered a Chlamydia pneumoniae infection verified by serology, and a nucleotide sequence was found in the heart and lung by means of the polymerase chain reaction (PCR) that hybridized with a probe specific for that organism. Male Swedish orienteers do not, however, seem to have an increased rate of exposure to this agent. No further sudden unexpected deaths among young orienteers have occurred over the past 3.5 years. At the beginning of that period, attempts were made to modify training habits and attitudes.
|
|
