Detection of the homology among proteins by immunochemical cross-reactivity between denatured antigens. Application to the glyceraldehyde 3-phosphate dehydrogenases from different species

It was previously proposed that an immunological cross-reaction between two denatured proteins is evidence for an homology betweeen their amino sequence (Arnon &; Maron, 1971; Arnheim et al., 1971) and that detection of such a cross-reaction could then be a rapid method to detect sequence homologies (Zakin et al., 1978). In order to test the possibilities of such a methodology, using proteins of known structure, glyceraldehyde 3-phosphate dehydrogenases from different sources are compared by immunochemical techniques. The antibodies raised against the native enzyme from E. coli K 12 can only recognize the homologous antigen, the glyceraldehyde 3-phosphate dehydrogenase from B. stearothermophilus and to a lesser extent that from halibut. In contrast, the antibodies raised against the denatured enzyme from E. coli K 12 can recognize the glyceraldehyde 3-phosphate dehydrogenases from man, ostrich, chicken, sturgeon, halibut, lobster and yeast, when in their denatured state. The present results show unambiguously that through exposure of buried sequences, the immunochemical detection of sequence homologies among proteins is more discriminating when unfolded proteins are used, rather than native ones. It is also proposed that the use of denatured proteins both as immunogens and antigens would be a useful tool in studying biochemical evolution.     

Efficacy and tolerance of recombinant tissue-type plasminogen activator in patients with thrombotic or embolic occlusions of leg-arteries

Summary The efficacy and safety of recombinant tissue-type plasminogen activator (rt-PA) was evaluated in 46 patients with thrombembolic arterial occlusions in leg arteries. rt-PA was given over 1–4 h with a maximum dose of 18 mg. The effect of rt-PA treatment was determined as patency of the occluded arteries in 44 different patients 14 days after treatment. In 41 patients at least one artery was recanalized (93%) by rt-PA, and in almost half of these patients (48%) no residual stenosis were detected after the lytic treatment. A slight residual stenosis was detected in 29% of the patients and a severe residual stenosis in 21%. An additional treatment with percutaneous transluminal angioplasty was performed in 23 of the 44 patients and successful in 21 (91%). In 8 patients an addition catheter-embolectomy was performed. No difference in patency rate was detected between patients with thrombotic and those with embolic occlusions. The age of the occlusion influenced the patency rate; occlusions under the age of 5 weeks showed a patency rate of 96% compared to 82% in older occlusions. The length of the occlusion did not have any influence on the outcome of the rt-PA treatment. From the results of this open study we conclude that a dose of up to 18 mg of rt-PA is both safe and effective in the treatment of thromboembolic occlusions in leg arteries.Abbreviations rt-PA recombinant tissue-type plasminogen activator - GGT gamma-glutamyltransferase - SGOT aspartate aminotransferase - SGPT alanine aminotransferase - LDH lactate dehydrogenase - PTA percutaneous transluminal angioplasty Dedicated to Prof. Dr. N. Zöllner on the occasion of his 70th birthday     

Pre‐conditioning activates adenosine utilization in a cost‐effective way during myocardial ischaemia

During pre‐conditioning the interstitial concentration of adenosine, in contrast to lactate, presents a die‐away curve‐pattern for every successive episode of ischaemia. This die‐away pattern might not necessarily be attributed to diminished adenosine production. The present study was undertaken to investigate whether pre‐conditioning alters the metabolic turnover of adenosine as observed by the lactate production during ischaemia. Interstitial levels of metabolites in pre‐conditioned (n=21) and non‐preconditioned (n=21) porcine hearts were monitored with microdialysis probes inserted in both ischaemic and non‐ischaemic tissue in an open chest heart model. Three subgroups perturbated with either plain microdialysis buffer (control), buffer containing adenosine (375 μM ), or buffer containing deoxyadenosine (375 μM ) were studied. All animals were subjected to 90 min of equilibrium microdialysis before 40 min of regional myocardial ischaemia and 120 min of reperfusion. Pre‐conditioning consisted of four repetitive episodes of 10 min of ischaemia and 20 min of reperfusion. Significantly higher levels of inosine and lactate were found in the ischaemic tissue of the pre‐conditioned subgroup receiving adenosine (P < 0.05) compared with the other two subgroups receiving deoxyadenosine and plain buffer, respectively. This difference was only valid for pre‐conditioned ischaemic myocardium, and hence equal amounts of inosine and lactate were produced in the non‐preconditioned ischaemic myocardium regardless of the presence of adenosine or deoxyadenosine. In the non‐ischaemic myocardium baseline levels of metabolites were measured in all subgroups. Pre‐conditioning favoured degradation of exogenous adenosine to inosine successively ending up in enhanced lactate production. This was probably because of the involvement of the hexose monophosphate pathway in the pre‐conditioned ischaemic myocardium. This route may therefore be supplementary in energy metabolism as a metabolic flow can be started by adenosine ending up in lactate without initial adenosine 5′‐triphosphate (ATP) investment. Utilization of adenosine in this way may also explain the successive die‐away pattern of adenosine seen in consecutive pre‐conditioning cycles.     

Identification of the three-element windkessel model incorporating a pressure-dependent compliance

A new one-step computational procedure is presented for estimating the parameters of the nonlinear three-element windkessel model of the arterial system incorporating a pressure-dependent compliance. The data required are pulsatile aortic pressure and flow. The basic assumptions are a steadystate periodic regime and a purely elastic compliant element. By stating two conditions, zero mean flow and zero mean power in the compliant element, peripheral and characteristic resistances are determined through simple closed form formulas as functions of mean values of the square of aortic pressure, the square of aortic flow, and the product of aortic pressure with aortic flow. The pressure across as well as the flow through the compliant element can be then obtained so allowing the calculation of volume variation and compliance as functions of pressure. The feasibility of this method is studied by applying it to both simulated and experimental data relative to different circulatory conditions and comparing the results with those obtained by an iterative parameter optimization algorithm and with the actual values when available. The conclusion is that the proposed method appears to be effective in identifying the three-element windkessel even in the case of nonlinear compliance.     

Does the amount of exercising muscle alter the aerobic demand of dynamic exercise?

The primary purpose of this study was to determine if the aerobic demand for production of specified power outputs is altered by distribution of work between the arms and legs compared with when all the work is performed by the legs. Because of the important exercise training implications, a secondary purpose of this study was to determine if the exercising muscle mass affects the cardiorespiratory demands at specified rating of perceived exertion (RPE) levels and blood lactate concentrations. Nine healthy adults completed leg cycling and combined arm and leg exercise on an Airdyne using a discontinuous protocol. Repeated measures ANOVA revealed that oxygen uptake for the combined arm and leg exercise averaged 0.04 l·min⁻¹ greater (p<0.05) than for leg cycling at the same external power outputs. However, RPE levels at specified power outputs were lower (p<0.05) with combined arm and leg exercise than leg cycling. At specified RPE levels and blood lactate concentrations, oxygen uptake and heart rate values were higher (p<0.05) for combined arm and leg exercise than leg cycling. From these findings we conclude that: (1) the addition of arm exercise to leg cycling results in a reduction in RPE, but a minimal increase in oxygen consumption to perform a given power output, and (2) if training intensity is established by RPE or blood lactate concentration, use of a muscle mass larger than that used in leg cycling should allow a greater cardiorespiratory training effect.     

Post-competition blood lactate concentrations in collegiate swimmers

Summary The purpose of this investigation was to quantitate post-competition lactate (LA) concentrations of swimmers during a competitive collegiate meet. Blood LA was measured by an enzymatic method on 23 subjects 5 min after each race event. The largest mean LA concentration of 25.7 mM/L was observed in swimmers after competing in the 200-yd individual medley. Swimmers in the 200-yd butterfly, back, breast and freestyle races had similar mean blood LA concentrations (ranging from 16.4 to 20.6 mM/L). Swimmers in the two longest events, the 500-yd and 1,000-yd free style races, had mean LA concentrations of 15.6 and 10.0 mM/L, respectively. To account for the effects of motivation, LA concentrations were measured following maximal effort noncompetitive 100 and 200-yd swims. LA concentrations were slightly greater in conjunction with faster performances for the competitive as compared to the noncompetitive 100 and 200-yd swims.     

Power and peak blood lactate at 5050 m with 10 and 30 s ‘all out’ cycling

Anecdotal observations suggest that the reduction in peak lactate accumulation in blood ([La]_{b peak}) after exhausting exercise, in chronic hypoxia vs. normoxia, may be related to the duration of the exercise protocol, being less pronounced after short supramaximal exercise than after incremental exercise (IE) lasting several minutes. To test this hypothesis, six healthy male Caucasians (age 36.8 ± 7.3, x¯ ± SD) underwent three exercise protocols on a cycle ergometer, at sea level (SL) and after 21 ± 10 days at 5050 m altitude (ALT): (1) 10 s, (2) 30 s ‘all out’ exercise and (3) IE leading to exhaustion in ～20–25 min. ‘Average’ power output (p¯) was calculated for 10 or 30 s ‘all out’; maximal power output (P_max) was determined for IE. Lactate concentration in arterialized capillary blood ([La]_b) was measured at rest and at different times during recovery; the highest [La]_b during recovery was taken as [La]_{b peak}. No significant differences in p¯ were observed between SL and ALT, for either 10 or 30 s ‘all out’ exercise; P_max during IE was significantly lower at ALT than at SL. [La]_{b peak} after 10 s ‘all out’ was unaffected by chronic hypoxia (7.0 ± 0.9 at ALT vs. 6.3 ± 1.8 mmol L^–1 at SL). After 30 s ‘all out’ the [La]_{b peak} decrease, at ALT (10.6 ± 0.6 mmol L^–1) vs. SL (12.9 ± 1.4 mmol L^–1), was only ～50% of that observed for IE (6.7 ± 1.6 mmol L^–1 vs. 11.3 ± 2.8 mmol L^–1). Muscle power output and blood lactate accumulation during short supramaximal exercise are substantially unaffected by chronic hypoxia.     

Age-Related Changes in Ceruloplasmin Content in W/SSM Rats

We studied enzyme systems (lactate dehydrogenase) of mitochondria in cerebral nerve cells in experimental encephalopathy developing after thermal injury. In animals receiving neuromedin at the early terms after injury, the ratio of forward to reverse lactate dehydrogenase reactions significantly increased over the first day after injury and returned to normal on day 7. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 145, No. 6, pp. 626–627, June, 2008     

Left heart function in chronic obstructive lung disease

Summary In patients with varying degrees of chronic obstructive pulmonary disease (COPD), simultaneous measurements of central hemodynamics and left ventricular radionuclide ventriculograms at rest and during exercise were made. In 21 of these patients, satisfactory echocardiograms could be performed. In seven of the patients, arterial blood pressure at rest was increased. Decreased compliance of the left ventricle was thought to be present in patients with COPD and additional arterial hypertension. The left ventricular ejection fraction (LVEF) at rest was in the high normal range in all patients. During exercise, no further increase was observed. This pattern of LVEF response seems to be typical in patients with COPD. Because the highest values were observed in the more severe COPD and right ventricular hypertrophy, it is unlikely that an impairment of left ventricular function is caused by COPD. In five of 27 patients, an abnormal decrease of LVEF and regional hypokinesis occurred during exercise, thus suggesting additional coronary heart disease. The fact that at least 30% of the patients with COPD suffered from arterial hypertension and 20% of the patients exhibited unexpected ischemia detected by regional hypokinesis in RNV during exercise, but not in the ECG, may be of practical relevance. Coronary angiography was not indicated because most of these patients were over 65 and the factor limiting the working capacity was ventilatory impairment and not angina pectoris, in all patients. For this reason, a diagnostic uncertainty remains with regard to additional coronary heart disease in the older patients with advanced chronic obstructive pulmonary disease.Lung Function Parameters VC (1) inspiratory vital capacity - FEV1 (1) forced exspiratory volume in 1 sec - Raw (cmH20/l/s) airways resistance - RV/TLC (%) residual volume/total lung capacity - paO₂ (mm Hg) O₂ partial pressure Hemodynamic Parameters CI (1/min/sqm) cardiac index - SVI (ml/sqm) stroke volume index - PAP (mm Hg) pulmonary artery mean pressure - PwP (mm Hg) pulmonary capillary wedge pressure - RRs (mm Hg) systolic arterial pressure - RRd (mm Hg) diastolic arterial pressure (at the time of catheterization) - RR(WHO) (mm Hg) mean values measured at different days (at least 3 values). Parameters Derived from Combined Radionuclide Ventriculography and Central Hemodynamics LVEF (%) left ventricular ejection fraction - LVESVI (ml/sqm) left ventricular endsystolic volume index - P/V (mm Hg/ml/sqm) peak systolic pressure/endsystolic volume index - PFR (1/sec) peak filling rate: endsystolic volume/sec Echocardiographic Parameters RV d wth (mm) right ventricular enddiastolic wall thickness - LV d wth (mm) left ventricular enddiastolic wall thickness In honor to Prof. W.E. Adam's 60th birthday