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- Allvin, Kerstin, 1970, et al.
(författare)
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Elevated serum levels of estradiol, dihydrotestosterone, and inhibin B in adult males born small for gestational age
- 2008
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Ingår i: Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 93:4, s. 1464-9
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Prenatal growth restriction may affect future fertility in both females and males. Studies have shown that growth-retarded male rats have different sexual behavior and disturbed steroidogenesis. OBJECTIVE: We hypothesized that adult human males born small for gestational age (SGA) have an altered sex hormone profile. DESIGN, SETTING, AND PATIENTS: Twenty-five adult males born SGA with median birth weight -2.2 sd scores (SDS) and birth length -2.4 SDS were studied. Median age was 23.1 yr and final height -0.5 SDS. They were compared with 44 male controls with median age 20.5 yr and final height 0.4 SDS. MAIN OUTCOME MEASURE: The primary outcome before the study started was 17beta-estradiol (E(2)) levels in SGA males. RESULTS: The SGA group showed significantly higher median levels of E(2), 17.9 pg/ml (P < 0.001), and dihydrotestosterone (DHT), 0.543 ng/ml (P < 0.05), compared with controls, 12.6 pg/ml and 0.423 ng/ml, respectively. Testosterone (T) levels did not differ between groups. E(2) to T ratio correlated negatively to birth weight (r = -0.40, P < 0.01) and birth length (r = -0.44, P < 0.001). DHT to T ratio correlated negatively to birth weight (r = -0.51, P < 0.001) and birth length (r = -0.38, P < 0.01). Males born SGA also had significantly higher median levels of inhibin B, 164 pg/ml (P < 0.05), compared with controls, 137 pg/ml. Inhibin B correlated negatively to birth length (r = -0.34, P < 0.01). CONCLUSION: SGA males of normal stature have higher levels of E(2), DHT, and inhibin B than controls, indicating a disturbed steroid synthesis or metabolism. Aromatase activity, calculated as E(2) to T ratio, and 5alpha-reductase activity, calculated as DHT to T ratio, is negatively correlated to size at birth.
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| 2. |
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| 3. |
- Fors, Carina, et al.
(författare)
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Analysis of breathing-related variations in ECG-triggered laser Doppler perfusion signals measured on the beating heart during surgery
- 2006
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Ingår i: Computers in cardiology. - 0276-6574. ; 33, s. 181-184
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Tidskriftsartikel (refereegranskat)abstract
- Laser Doppler perfusion monitoring (LDPM) is amethod to assess microvascular perfusion. A modified,ECG-triggered LDPM system has been developed tomeasure myocardial perfusion with minimum influencefrom heart motion. With this method, one systolic (PLS)and one diastolic (PLD) perfusion value is obtained.The aim of this study was to analyse breathing-relatedvariations in PLS and PLD measured during open-heartsurgery. The phase delays between PLS, PLD, meanarterial blood pressure (MAP), heart rate and, indirectly,the respiration were determined.MAP tended to be in phase with or precede thevariations in PLD, i.e., PLD was at a maximum at the endof inspiration or at the beginning of expiration. No clearrelation between PLS and any of the other signals couldbe found.
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| 4. |
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| 5. |
- Fors, Carina, 1978-
(författare)
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Evaluation of a Laser Doppler System for Myocardial Perfusion Monitoring
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Coronary artery bypass graft (CABG) surgery is a common treatment for patients with coronary artery disease. A potential complication of CABG is myocardial ischemia or infarction. In this thesis, a method - based on laser Doppler flowmetry (LDF) - for detection of intra- and postoperative ischemia by myocardial perfusion monitoring is evaluated.LDF is sensitive to motion artifacts. In previous studies, a method for reduction of motion artifacts when measuring on the beating heart has been developed. By using the ECG as a reference, the perfusion signal is measured in intervals during the cardiac cycle where the cardiac motion is at a minimum, thus minimizing the artifacts in the perfusion signal.The aim of this thesis was to investigate the possibilities to use the ECG-triggered laser Doppler system for continuous monitoring of myocardial perfusion in humans during and after CABG surgery. Two studies were performed. In the first study, changes in myocardial perfusion during CABG surgery were investigated (n = 13), while the second study focused on postoperative measurements (n = 13). In addition, an ECG-triggering method was implemented and evaluated.It was found that the large variations in myocardial perfusion during CABG surgery could be monitored with the ECG-triggered laser Doppler system. Furthermore, a perfusion signal of good quality could be registered postoperatively from the closed chest in ten out of thirteen patients. In eight out of ten patients, a proper signal was obtained also the following morning, i.e., about 20 hours after probe insertion. The results show that respiration and blood pressure can have an influence on the perfusion signal.In conclusion, the results indicate that the method is able to detect fluctuations in myocardial perfusion under favourable circumstances. However, high heart rate, abnormal cardiac motion, improper probe attachment and limitations in the ECG-triggering method may result in variations in the perfusion signal that are not related to tissue perfusion.
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| 6. |
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| 7. |
- Fors, Carina, et al.
(författare)
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Night-time traffic in urban areas : a literature review on road user aspects
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this literature study is to review recent research on night-time traffic from a road user perspective. The report discusses road users' behaviour, needs and problems in relation to other road users as well as to traffic environment. The study includes 128 references from 1998-2008 and it mainly concerns urban areas. The report begins with a chapter about accident statistics, followed by a theoretical background that includes lighting terminology, Swedish regulations on road equipment, and the human eye and night vision. The main part of the report has its focus on five road user groups - drivers, pedestrians, bicyclists, older people and visually impaired people - and their needs, difficulties, performances and behaviour in night-time traffic. The literature gives relatively much information about drivers' situation in night-time traffic, but there is a lack of knowledge in some areas such as drivers' interaction with parts of the driving environment. Also, there is partly a lack of knowledge on pedestrians and older road users. Regarding bicyclists and visually impaired people, there is only very limited literature available.
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| 8. |
- Fors, Carina, 1978-, et al.
(författare)
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Online Laser Doppler Measurements of Myocardial Perfusion
- 2008
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Ingår i: IFMBE Proceedings 22,2008. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783540892076 - 9783540892083 ; , s. 1718-1721
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Konferensbidrag (refereegranskat)abstract
- Laser Doppler perfusion monitoring is a suitable method for microvascular blood perfusion measurements. When used on a moving tissue or organ, the Doppler signal arising from the moving blood cells may be distorted. ECG triggering of the laser Doppler signal can be used for reducing the influence from movements during measurements on the beating heart. The aim of this study was to determine the most appropriate triggering intervals during the cardiac cycle for online measurements. Recordings from thirteen coronary artery bypass graft (CABG) patients were included in the study. During surgery, the fibre-optic probe was passed through the chest wall and sutured to the left anterior ventricular wall with the probe tip inserted 3–5 mm into the myocardium. After the patient arrived at the intensive care unit a second measurement was initiated and lasted for about two hours. Before the probe was removed a third measurement was performed for about 5 minutes the following morning. A total of 97 data sequences were analysed and the intervals of low and stable perfusion signal were compared to the positions of the T and P peaks in the ECG.It was found that the most appropriate time intervals were in late systole at the T peak [−3, 9] ms and just before the P peak [−28, -10] ms in late diastole. However, the position of these intervals may vary between individuals, because of e.g., abnormal cardiac motion. With the use of the appropriate interval online measurement of the myocardial perfusion on a beating heart appears possible.
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| 9. |
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| 10. |
- Karlsson, Daniel M. G., et al.
(författare)
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Myocardial perfusion monitoring during coronary artery bypass using an electrocardiogram-triggered laser Doppler technique
- 2005
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Ingår i: Medical and Biological Engineering and Computing. - : Springer. - 0140-0118 .- 1741-0444. ; 43:5, s. 582-588
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Tidskriftsartikel (refereegranskat)abstract
- Electrocardiogram (ECG)—triggered laser Doppler perfusion monitoring (LDPM) was used to assess myocardial perfusion, with minimum myocardial tissue motion influence, during coronary artery bypass grafting (CABG). Thirteen subjects were investigated at six phases: pre- and post-CABG; post aorta cross-clamping; pre and post left internal mammary artery (LIMA) graft declamping; and post aorta declamping. The perfusion signal was calculated in late systole and late diastole, with expected minimum tissue motion, and compared with arrested heart measurements. Patient conditions or artifacts caused by surgical activity made it impossible to perform and analyse data in all six phases for some patients. No significant (n=5) difference between perfusion signals pre- and post-CABG was found. Diastolic perfusion signal levels were significantly (p<0.02) lower compared with systolic levels. After aorta cross-clamping, the signal level was almost zero. A distinct perfusion signal increase after LIMA and aorta declamping, compared with pre-LIMA declamping, was found in ten cases out of 13. A significantly (p<0.04) lower perfusion signal in the arrested heart compared with in the beating heart was registered. Influence from mechanical ventilation was observed in 14 measurements out of 17. In conclusion, ECG-triggered LDPM can be used to assess myocardial perfusion during CABG. Perfusion signals were lower in the arrested heart compared with in the beating heart and in late diastole compared with late systole. No significant difference between pre- and post-CABG was found.
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