Structural and immunologic characterization of bovine, horse, and rabbit serum albumins

Serum albumin (SA) is the most abundant plasma protein in mammals. SA is a multifunctional protein with extraordinary ligand binding capacity, making it a transporter molecule for a diverse range of metabolites, drugs, nutrients, metals and other molecules. Due to its ligand binding properties, albumins have wide clinical, pharmaceutical, and biochemical applications. Albumins are also allergenic, and exhibit a high degree of cross-reactivity due to significant sequence and structure similarity of SAs from different organisms. Here we present crystal structures of albumins from cattle (BSA), horse (ESA) and rabbit (RSA) sera. The structural data are correlated with the results of immunological studies of SAs. We also analyze the conservation or divergence of structures and sequences of SAs in the context of their potential allergenicity and cross-reactivity. In addition, we identified a previously uncharacterized ligand binding site in the structure of RSA, and calcium binding sites in the structure of BSA, which is the first serum albumin structure to contain metal ions.     

New method of intracoronary adenosine injection to prevent microvascular reperfusion injury in patients with acute myocardial infarction undergoing percutaneous coronary intervention

The aim of our study was to examine the role of a new, simple protocol of intracoronary adenosine administration performed during primary angioplasty on the immediate angiographic results and clinical course. A prospective, single-center, randomized, placebo-controlled trial of 70 consecutive patients (64 ± 14 years, 54 men) with acute myocardial infarction with ST-segment elevation undergoing primary percutaneous coronary intervention (PCI) was conducted. Patients were randomized to 2 groups. Group 1 (n = 35) received intracoronary adenosine (1 to 2 mg) with a hand injection through the guiding catheter 2 times: immediately after crossing the lesion of the infarct-related artery with guidewire and then after the first balloon inflation. Group 2 (n = 35) received placebo. The baseline clinical and angiographic characteristics of the 2 groups were similar. Percutaneous coronary intervention resulted in Thrombolysis In Myocardial Infarction grade 3 flow after PCI in 32 patients (91.4%) in the adenosine group and 27 patients (77.1%) in the placebo group (p = 0.059). Myocardial blush grade 3 was observed at the end of PCI in 23 patients (65.7%) in the adenosine group and 13 (37.1%) in the placebo group (p < 0.05). Resolution of ST-segment elevation (> 50%) was more frequently observed in the adenosine than in the placebo group: 27 (77%) versus 15 (43%), respectively (p < 0.01). In conclusion, intracoronary adenosine administration improved the angiographic and electrocardiographic results in patients with acute myocardial infarction with ST-segment elevation undergoing PCI. Adenosine administration seemed to be associated with a more favorable clinical course.     

Ankle-brachial pressure index estimated by laser Doppler in patients suffering from peripheral arterial obstructive disease

Ankle-brachial index (ABI) measurements are widely used for evaluating the functional state of circulation in the lower limbs. However, there is some evidence that the value of ABI does not accurately reflect the degree of walking impairment in symptomatic patients with peripheral arterial obstructive disease (PAOD). We investigated the diagnostic value of ABI estimated by means of laser Doppler flowmetry (IT) for evaluating limb ischemia. We wanted to know whether laser Doppler could be more sensitive than the Doppler method in predicting walking capacity in patients with stable intermittent claudication. We analyzed a group of 30 patients with intermittent claudication (Fontain II, II/III) who were admitted for reconstructive treatment. There were 21 men and 9 women, aged 46-74 (mean 61) years. All patients underwent the treadmill test, and pain-free walking distances were measured. In each patient, we measured ABI using the two different methods: Doppler ultrasound device (ABI-Doppler) and laser Doppler (ABI-laser Doppler). The claudication distances were 25-200 m (mean 73 +/- 50.2 m). ABI-Doppler was 0.2-0.7 (0.582 +/- 0.195). ABI-laser Doppler measurements were 0.581 (+/-0.218). A correlation was found between ABI-Doppler and claudication distance (r = 0.46, P = 0.009). Also, ABI-laser Doppler values significantly correlated with claudication distances (r = 0.536, P = 0.002). The ABI evaluated by laser Doppler correlated well with claudication distances in patients with PAOD. Comparison of Doppler and laser Doppler measurements used for determining ABI showed that both methods have similar predictive power for walking capacity; however, higher correlation was observed between claudication distances and ABI measured by laser Doppler flowmetry. ABI-laser Doppler measurements are easier, are quicker, and seem to be better suited for noncompliant patients. Further investigation should be undertaken to determine whether laser Doppler is superior to the Doppler method in advanced occlusive arterial disease.     

Shortening baroreflex delay in hypertrophic cardiomyopathy patients – an unknown effect of β-blockers

Aims

Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy and impaired diastolic and systolic function. Abnormal sympathetic–parasympathetic balance is a potential stimulus for left ventricular hypertrophy in HCM patients. β-Blockers are routinely used in HCM for their strong negative inotropic effect; however, these drugs also influence the sympathetic–parasympathetic balance. This study aimed to determine the autonomic control of the cardiovascular system and the autonomic effects of β-blockers in HCM patients treated or untreated with β-blockers.

Methods

Among 51 HCM outpatients (18–70 years old; 29 men) there were 19 individuals with no medication and 32 subjects treated with a β-blocker. Fourteen age- and gender-matched (23–70 years old; nine men) healthy volunteers were enrolled in the control group. Continuous, non-invasive finger blood pressure was recorded during supine rest for 30 min. Autonomic regulation of the cardiovascular system was measured by heart rate variability and spontaneous baroreflex function (cross-correlation sequence method).

Results

The mean pulse interval, time domain and spectral measures of heart rate variability and baroreflex sensitivity were comparable between HCM patients, treated or not with β-blockers, and the control group. However, the delay of the baroreflex was significantly longer in HCM patients who were not treated with β-blockers [2.0 (1.6–2.3) s] in comparison with HCM patients receiving β-blockers [1.4 (1.1–1.8) s; P = 0.0072] or control subjects [1.2 (0.8–1.8) s; P = 0.0025]. This delay did not differ between HCM patients treated with β-blockers and the control group.

Conclusions

Hypertrophic cardiomyopathy not treated with β-blockers is accompanied by prolonged baroreflex delay. The use of β-blockers normalizes this delay.