Ischaemia-modified albumin during experimental apnoea

Ischaemia-modified albumin (IMA) is a marker of the release of reactive oxygen species (ROS) during hypoxaemia. In elite divers, breath-hold induces ROS production. Our aim was to evaluate the kinetics of IMA serum levels during apnea. Twenty breath-hold divers were instructed to perform a submaximal static breath-hold. Twenty non-diver subjects served as controls. Blood samples were collected at rest, every minute, at the end of breath-hold, and 10 min after recovery. The IMA level increased after 1 min of breath-hold (p < 0.003) and remained high until recovery. Divers were separated into 2 groups: subjects who held their breath for less than 4 min (G-4) and those who held it for more than 4 min (G+4). After 3 min of apnoea, the increase of IMA was higher in the G-4 group than in the G+4 group (p < 0.008). However, at the end of apnoea, the IMA level did not differ between groups. If IMA level was globally correlated with the apnoea duration, it is interesting to note that the higher IMA level was not found in the best divers. Similarly, if arterial blood oxygen saturation (SpO2) was globally inversely correlated with apnoea duration, the lowest SpO2 at the end of breath-hold was not found in the divers that performed the best apnoea. We concluded that these divers save their oxygen. The IMA level provides a useful measure of resistance to hypoxaemia.

Evaluation of serum ischemia modified albumin levels in acute rheumatic fever before and after therapy

OBJECTIVE

To investigate ischemia modified albumin (IMA) levels in children with acute rheumatic fever (ARF) before and after therapy and compare them with those of controls.

METHODS

Twenty seven patients with ARF and 18 healthy, age and sex matched children were included in the study. The diagnosis of ARF was established according to the modified Jones criteria. Follow-up studies were made when acute phase reactants [erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)] levels returned normal. IMA levels were measured using the rapid and colorimetric method with the albumin cobalt binding test.

RESULTS

IMA levels were significantly higher in ARF group (p < 0.001) compared with controls at the time on admission. IMA (absorbance units) was measured as 0.41 ± 0.10 in the control group, 0.55 (0.44-1.13) in the study group before treatment and 0.48 ± 0.12 in the study group after treatment. After treatment, statistically important decrements were determined in the levels of ESR (p<0.001), CRP (p<0.001) and IMA (p<0.01). There was no significant difference for IMA levels between after treatment and control group. IMA levels at the time on admission correlated positively with ESR (r = 0.605, p < 0.01) and CRP (r = 0.543, p < 0.01).

CONCLUSIONS

The present study shows that increased serum IMA levels in patients with ARF at the time of diagnosis is a sign of increased inflammation. Thus, serum IMA levels may be used as a follow-up marker like CRP and ESR for evaluating the efficacy of treatment in ARF.

Biochemical markers in acute coronary syndrome

Owing to their higher risk for cardiac death or ischemic complications, patients with acute coronary syndrome (ACS) must be identified from other causes of chest pain. Patients with acute coronary syndrome are divided into categories based on their electrocardiogram; those with new ST-segment elevation and those who present with ST-segment depression. The subgroups of patients with ST-segment elevation are candidates for immediate reperfusion, while fibrinolysis appears harmful for those with non-ST elevation myocardial infarction. There is increasing evidence to encourage appropriate risk stratification before deciding on a management strategy (invasive or conservative) for each patient. The TIMI, GRACE or PURSUIT risk models are recommended as useful for decisions regarding therapeutic options. Cardiac biomarkers are useful additions to these clinical tools to correctly risk stratify ACS patients. Cardiac troponin is the biomarker of choice to detect myocardial necrosis and is central to the universal definition of myocardial infarction. The introduction of troponin assays with a lower limit of detection will allow for earlier diagnosis of patients who present with chest pain. Analytical and clinical validations of these new assays are currently in progress. The question is whether the lower detection limit of the troponin assays will be able to indicate myocardial ischemia in the absence of myocardial necrosis. Previous to the development of ultrasensitive cardiac troponin assays free fatty acids unbound to albumin and ischemia modified albumin were proposed as biochemical markers of ischemia. Advances in our knowledge of the pathogenesis of acute coronary thrombosis have stimulated the development of new biomarkers. Markers of left ventricular performance (N-terminal pro-brain natriuretic peptide) and inflammation (e.g. C-reactive protein) are generally recognized as risk indicators. Studies suggest that using a number of biomarkers clinicians can risk stratify patients over a broad range of short and long term cardiac events. Nevertheless, it is still under debate as to which biomarker combination is best preferred for risk prediction. This review will focus on recent practice guidelines for the management of patients with ACS as well as current advances in cardiac biomarkers, their integration into clinical care and their diagnostic, prognostic and therapeutic utility.