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- Akerud, Helena, et al.
(author)
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Lactate distribution in culture medium of human myometrial biopsies incubated under different conditions
- 2009
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In: American Journal of Physiology. Endocrinology and Metabolism. - : American Physiological Society. - 0193-1849 .- 1522-1555. ; 297:6, s. E1414-E1419
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Journal article (peer-reviewed)abstract
- It is generally believed that a relationship exists between muscle fatigue and intracellular accumulation of lactate. This reasoning is relevant to obstetrical issues. Myocytes in uterus work together during labor, and the contractions need to be strong and synchronized for a child to be delivered. At labor dystocia, the progress of labor becomes slow or arrested after a normal beginning. It has been described that, during labor dystocia, when the force of the contractions is low, the uterus is under hypoxia, and anaerobic conditions with high levels of lactate in amniotic fluid dominate. The purpose of this study was to examine whether myometrial cells are involved in the production of lactate in amniotic fluid and whether there are differences in production and distribution of lactate in cells incubated under aerobic and anaerobic conditions. We also wanted to elucidate the involvement of specific membrane-bound lactate carriers. Women undergoing elective caesarean section were included. Myometrial biopsies from uteri were collected and subjected to either immunohistochemistry to identify lactate carriers or in vitro experiments to analyze production of lactate. The presence of lactate carriers named monocarboxylate transporters 1 and 4 was verified. Myometrial cells produced lactate extracellularly, and the lactate carriers operated differently under anaerobic and aerobic conditions; while being mainly unidirectional under anaerobic conditions, they became bidirectional under aerobic conditions. Human myometrial cells produced and delivered lactate to the extracellular medium under both anaerobic and aerobic conditions. The delivery was mediated by lactate carriers.
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| 2. |
- Bolin, Marie, et al.
(author)
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Angiopoietin-1/angiopoietin-2 ratio for prediction of preeclampsia
- 2009
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In: American Journal of Hypertension. - : Oxford University Press (OUP). - 0895-7061 .- 1941-7225. ; 22:8, s. 891-895
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Journal article (peer-reviewed)abstract
- BACKGROUND: A number of different biophysical and biochemical markers have been proposed as predictors of preeclampsia. Factors involved in the angiogenic balance are suggested as candidate markers. The purpose of this prospective, longitudinal cohort study was to determine whether a ratio between Angiopoietin-1 (Ang-1) and Angiopoietin-2 (Ang-2) can be used to predict preeclampsia in a low-risk population. METHODS: A cohort of healthy pregnant women (n = 469) were enrolled at gestational weeks 8-12. Plasma samples were collected at gestational weeks 10, 25, 28, 33, and 37. By using commercially available enzyme-linked immunosorbent assay kits Ang-1 and Ang-2 were analyzed. RESULTS: The median Ang-1/Ang-2 ratio increased during pregnancy in all women, but the ratios were significantly lower at gestational weeks 25 and 28 in women who later developed preeclampsia than in normal pregnant women (1.49 compared to 2.19 and 2.12 compared to 3.54, P < 0.05 and P < 0.05). CONCLUSION: Our data indicate that in a low-risk population of women the Ang-1/Ang-2 ratio in plasma constitutes a possible biomarker for prediction of later onset of preeclampsia.
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| 3. |
- Wiberg-Itzel, Eva
(author)
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Ante partum determination of lactate in amniotic fluid
- 2005
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Licentiate thesis (other academic/artistic)abstract
- Background: The present studies were conducted to investigate whether lactate determination in vaginal fluids, 'Lac-test', could be used as a diagnostic test for prelabour rupture of membranes (PROM). To derive the best cut-off value for a positive test and to asses weather lactate determination in vaginal fluid was associated with, and could predict, onset of labour for woman with suspect PROM. Lactate concentration was measured with the commercially available Lactate ProTM an electrochemical test strip method which needs only 5ul of fluid to analyze the lactate concentration. The test was carried out bedside and the result was available after 60 seconds. The studies were made as prospective observational studies in labour ward at Söder hospital Stockholm years 2002-2003. Paper I. Two hundred women with a history of suspect PROM after 34 weeks gestation were selected for determination of lactate concentrations in vaginal fluid. In 100 of these cases, actim PROM testTM were also analyzed. Sensitivity, specificity, positive and negative predictive values and Kappa indices were calculated. Results: A lactate concentration > 4.5 mmol/l was found to be the best cut-off value for a positive test. 'Lac-test' had a sensitivity of 86% (95% C.I. 77-96%), specificity 92% (95% C.I 84-99%), positive and negative predictive values of 92% and 87%, respectively. Likelihood ratio (LR) for a positive Lac-test was 10.75 and for a negative test 0. 15. The Kappa index for the 'Lactest' was 78%. Paper II. One hundred and seventy nine women attending labour ward at Söder hospital with suspect PROM after 34 weeks gestation were selected for determination of lactate concentrations in vaginal fluid. Association between time to spontaneous onset of labour within 24 hours and 48 hours and lactate concentration in vaginal fluid was analyzed. Results: The median time interval between examination and spontaneous onset of labour was 8.4 hours for those with "high" lactate (> 4.5 mmol/l) and 54 hours for those with "low" lactate concentrations (< 4.5 mmol/l). Among women with "high" lactate concentrations 76 (88%) started in labour within 24 hours, as compared with 20 (21%) for those with "low" lactate concentration, giving an Odds Ratio (OR) of 27.7; 95% C.I. 12-63.3. Conclusion: Lactate determination is a valid test in cases with a history of suspects PROM. High lactate concentration (> 4.5 mmol/l) in vaginal fluid is strongly associated with, and can predict, woman with suspect PROM spontaneous onset of labour within 24 hours and 48 hours.
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| 4. |
- Wiberg-Itzel, Eva
(author)
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Lactate determination in ante- and intrapartum surveillance
- 2007
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Doctoral thesis (other academic/artistic)abstract
- Lactate concentration is reported to be high in amniotic fluid (AF). Prelabour rupture of membranes (PROM) occur in about 20% of all pregnancies. The condition is associated with fetal and maternal complications, and might be a marker of imminent delivery. Therefore among women with suspected prelabour rupture of the membranes (PROM), it is of great importance to accurately confirm the diagnosis. In our studies we wanted to assess whether lactate determination in vaginal/amniotic fluid could be used as a diagnostic test for prelabour rupture of membranes, and could predict onset of labour in women with suspected PROM. We selected women with a history of suspect PROM after 34 weeks gestation for determination of lactate concentrations in vaginal fluid. A lactate concentration > 4.5 mmol/l was found to be the best cut-off value for a positive ‘Lactest’ and showed a sensitivity of 86% and specificity 92%.The median time interval between examination and spontaneous onset of labour among the women with `high´ lactate (> 4.5 mmol/l) were 8.4 hours and for those with `low´ lactate concentration (< 4.5 mmol/l) 54 hours. Among women with `high´ lactate concentration 88% started in labour within 24 hours, as compared with 21% for those with `low´ lactate concentration. Labour dystocia is clinically defined as slow or arrest of progress during labour and is a common obstetrical problem worldwide. In our study we looked for an association between high lactate concentration in amniotic fluid and labour dystocia. We selected women in active labour attending labour ward, and performed at least two consecutive measurements of lactate concentration in amniotic fluid during labour. Among women with spontaneous vaginal deliveries (n=23) the mean lactate concentration in AF during labour was 8.9 mmol/l and among women with labour dystocia (n=31) the corresponding value was 10.9 mmol/l (p <0.001). Of 29 women with a high lactate concentration (>10.1 mmol/l) in at least two consecutive measures, 86% were delivered instrumentally/operatively due to dystocia. Using this definition of a positive test gives a sensitivity of 81% a specificity of 82%, a positive predictive value of 86%, and a negative predictive value of 76%. Fetal surveillance during labor is often based on fetal heart rate monitoring using the cardiotocograph (CTG). A normal CTG is reassuring for a well oxygenated fetus. However, a non-reassuring trace occurs in up to 50% of all recordings, but only a small proportion of these fetuses are at risk of hypoxia. In a multicentre trial we wanted to compare pH vs. lactate analysis, regarding prevention of acidemia at birth. 2992 women in labour were randomised to pH (n=1,496) or lactate analysis (n=1,496). Protocol violations were significantly less frequent in women randomised to lactate compared with women randomised to pH analysis, 11.0% vs. 1.5%. There were no significant differences between the groups in the rate of metabolic acidemia (RR 0.96) or pH <7.00 (RR 0.88) in cord artery blood at birth. We have with this thesis shown the usefulness of determination of lactate in AF and fetal blood sampling. Lactate in AF can be used in the diagnosis of suspected PROM, in the prediction of spontaneous onset of labour for women with suspected PROM, and also in the diagnosis of labour dystocia. We have shown lactate analysis of fetal scalp blood to be at least as good as pH analysis in the management of intrapartum fetal distress.
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