Metabolic changes during exercise testing of patients with ischaemic heart disease

The applicability of a complement consumption assay as a means by which to detect IgG aggregates and immune complexes in serum was examined. Both heavy (greater than or equal to 19S) and intermediate (11-17S) IgG aggregates were detected and the sensitivity of the assay was greater than or equal to 10 mug aggregated IgG/ml. BSA anti-BSA complexes, formed in slight antibody excess, were detected at a BSA concentration of 200 ng/ml. NHS stored at 4degreesC for greater than or equal to 2-3 weeks or at -20degreesC for more than 3 months developed distinct anticomplementarity (AC). This background AC, due to IgG aggregate formation, was reduced by heating the serum at 56degreesC for 50 min prior to testing. A similar reduction of AC and C1q fixation was observed when IgG aggregated at 61degreesC or 63degreesC was heated further at 56degreesC for 50 min. The abatement of AC could not be correlated to a change in IgG aggregation size. In contrast, AC of preformed antigen-antibody complexes was not reduced by this heat treatment.     

Respiratory gas exchange. Anesthesia with enflurane or isoflurane in nitrous oxide during spontaneous and controlled ventilation

The estimation of oxygen consumption and carbon dioxide elimination is essential for predicting the metabolic activity and needs of any patient having anaesthesia. During anaesthesia oxygen consumption can be measured and compared to a predicted value. However, oxygen uptake is affected by anaesthetic agents, which complicates the interpretation of measured oxygen uptake rate. The purpose of this study was to investigate whether there are any differences in respiratory gas exchange during anaesthesia with enflurane and isoflurane and also to assess the effects of spontaneous versus controlled ventilation. METHODS. Forty orthopedic patients were randomized to enflurane or isoflurane anaesthesia in nitrous oxide with either spontaneous or controlled ventilation. A fresh low-gas-flow technique was used. Inspiratory oxygen and end-tidal carbon dioxide concentrations and expiratory minute ventilation were measured in a circle absorber system between the y-piece and the endotracheal tube with a sampling analyser. Between the mixing box and the absorption canister, carbon dioxide concentration was continuously measured. The carbon dioxide elimination was calculated from mixed expired concentration and expiratory minute ventilation. Excess gas was collected every 10 min in a non-permeable mylar plastic bag connected to the excess valve. The excess gas flow was calculated and the oxygen uptake rate was assumed to be the difference between the oxygen fresh gas flow and the oxygen excess gas flow. RESULTS. The grand mean oxygen uptake rate was 2.5 ml.kg-1 x min-1 or 100 ml.min-1 x m-2. There were no statistically significant differences in oxygen uptake between enflurane and isoflurane anaesthesia or between spontaneous and controlled ventilation. The mean oxygen uptake rate at 10 min was between 2.0 and 2.2 ml.kg-1 x min-1 in all groups. At 30 min the mean oxygen uptake rates were 2.6 to 2.8 ml.kg-1 x min-1. Carbon dioxide elimination was closely associated with expired minute ventilation, with a carbon dioxide excretion of about 30 ml per litre gas exhaled, irrespective of ventilatory mode employed.     

Carvedilol: the new role of beta blockers in congestive heart failure

The prognosis remains poor for patients with congestive heart failure (CHF), despite reduced mortality rates resulting from the addition of angiotensin converting enzyme inhibitors to traditional treatment regimens. Because much of the myocardial damage that occurs in patients with CHF may be related to sympathetic activation, interest in the use of beta blockers has grown. Recent studies have shown the benefits of beta blocker therapy in many patients with heart failure. Carvedilol, the first beta blocker labeled in the United States specifically for the treatment of heart failure, has been shown to improve left ventricular ejection fraction and may reduce mortality.     

Effects of sustained ligustrazine on hemorrheology in patients with chronic pulmonary heart disease

Before and after oral administration of sustained Ligustrazine, changes of hemorrheology and TXA2/PGI2 were evaluated in 16 patients with advanced chronic pulmonary heart disease. A decrease in whole blood and plasma viscosity, and reductions in hematocrit and fibrinogen were found after one course of treatment with sustained Ligustrazine. The mechanism of these effects may be related to improved modulation of imbalance of TXA2/PGI2 in patients with advanced chronic pulmonary heart disease.     

The safety of treadmill exercise stress testing in patients with abdominal aortic aneurysms

We retrospectively compared patients with NF1 with and without optic pathway gliomas (OPG) to determine the incidence and range of orbital developmental abnormalities and compared the incidence of OPG in African-Americans and whites. From cranial MR scans, we manually measured 14 orbital dimensions, compared them to published standards of Waitzman et al, calculated orbital volumes, and determined the presence or absence of volumetric symmetry (delta v) (delta v < or = 3 cm3 was considered to be symmetrical). We compared the results of orbital configurational assessment between patients with (group I) and those without OPG (group II). The study population comprised 58 patients, 24 boys, 18 African-American, and one Hispanic. Median age at imaging was 7 years (range 0.5-25.5 years). Fifty-eight percent had conformational abnormalities, 16 of whom had more than one abnormality (28%), the most frequent being increased intertemporal distance (n=10), increased lateral orbital distance (n=8), increased medial wall length (n=6), and decreased medial wall length (n=6). The increased intertemporal and lateral orbital distances may contribute to the appearance of hypertelorism. Only two patients had sphenoid wing hypoplasia. We found a high incidence of orbital dimensional abnormalities in the total population but more often saw multiple abnormalities in patients with OPG. However, no pattern of configurational abnormality emerged. OPG is less frequent in African-Americans. Orbital volumetric disparity seems to be independent of the presence of OPG.     

The effect of voluntary hyperventilation on arterial blood gases and gas exchange in patients with chronic obstructive lung disease

A 2 min test of voluntary hyperventilation (VHV) was performed on 19 patients with chronic obstructive lung disease (COLD) and on eight control subjects. The average decrease in PaCO2 in the patients in this test was 4.6 mmHg (11%) and the average increase in PaO2 was 12.3 mmHg (19.1%). The average decrease of PaCO2 in control subjects was 16.5 mmHg (48.6%) and the average increase in PaO2 was 38.0 mmHg (46.2%). In patients with COLD, PaCO2 changes during VHV correlated significantly with respiratory exchange ratio; the correlation with minute and alveolar ventilation and deltaVO2/deltaVE ratio during VHV was of borderline significance. PaCO2 changes during VHV did not correlate with FEV1 (percent of predicted) or FEV1/VC%. The possible mechanisms of changes in blood gas tensions during and after the end of VHV test are discussed. The VHV test seems to be useful in evaluation of patients with COLD.     

Effects of picotamide on release of endothelin-1, thromboxane and prostacycline after treadmill stress in patients with peripheral artery disease

To assess the effects of picotamide, an antithromboxane receptor and antithromboxane synthase drug, on vascular function and endothelin-1 release, 20 patients with peripheral arterial disease, without hypertension or diabetes mellitus, receiving placebo and picotamide (900 mg/day) were studied. The modifications of vascular parameters were evaluated by arterial distensibility index and postischemic hyperemia test (postischemic perfusion index and recovery time). Endothelin-1, prostacycline, and thromboxane B2 were determined under resting conditions and after treadmill test. Picotamide treatment caused a decrease of resting thromboxane B2 and endothelin-1 concentrations, produced an improvement of the vascular function as seen by the increase of vascular parameters reported, and attenuated the ischemic treadmill-induced increase of thromboxane B2, but not of endothelin-1. These data confirm that the picotamide improved vascular flow by the reduction of thromboxane-mediated effects, reduced resting endothelin-1 levels, but did not attenuate endothelin-1 concentrations induced by the treadmill stress.     

Mechanisms of worsening gas exchange during acute exacerbations of chronic obstructive pulmonary disease

This study was undertaken to investigate the mechanisms that determine abnormal gas exchange during acute exacerbations of chronic obstructive pulmonary disease (COPD). Thirteen COPD patients, hospitalized because of an exacerbation, were studied after admission and 38+/-10 (+/-SD) days after discharge, once they were clinically stable. Measurements included forced spirometry, arterial blood gas values, minute ventilation (V'E), cardiac output (Q'), oxygen consumption (V'O2), and ventilation/perfusion (V'A/Q') relationships, assessed by the inert gas technique. Exacerbations were characterized by very severe airflow obstruction (forced expiratory volume in one second (FEV1) 0.74+/-0.17 vs 0.91+/-0.19 L, during exacerbation and stable conditions, respectively; p=0.01), severe hypoxaemia (ratio between arterial oxygen tension and inspired oxygen fraction (Pa,O2/FI,O2) 32.7+/-7.7 vs 37.6+/-6.9 kPa (245+/-58 vs 282+/-52 mmHg); p=0.01) and hypercapnia (arterial carbon dioxide tension (Pa,CO2) 6.8+/-1.6 vs 5.9+/-0.8 kPa (51+/-12 vs 44+/-6 mmHg); p=0.04). V'A/Q' inequality increased during exacerbation (log SD Q', 1.10+/-0.29 vs 0.96+/-0.27; normal < or = 0.6; p=0.04) as a result of greater perfusion in poorly-ventilated alveoli. Shunt was almost negligible on both measurements. V'E remained essentially unchanged during exacerbation (10.5+/-2.2 vs 9.2+/-1.8 L x min(-1); p=0.1), whereas both Q' (6.1+/-2.4 vs 5.1+/-1.7 L x min(-1); p=0.05) and V'O2 (300+/-49 vs 248+/-59 mL x min(-1); p=0.03) increased significantly. Worsening of hypoxaemia was explained mainly by the increase both in V'A/Q' inequality and V'O2, whereas the increase in Q' partially counterbalanced the effect of greater V'O2 on mixed venous oxygen tension (PV,O2). We conclude that worsening of gas exchange during exacerbations of chronic obstructive pulmonary disease is primarily produced by increased ventilation/perfusion inequality, and that this effect is amplified by the decrease of mixed venous oxygen tension that results from greater oxygen consumption, presumably because of increased work of the respiratory muscles.     

Effects of prior arm exercise on pulmonary gas exchange kinetics during high-intensity leg exercise in humans

The activation of MAPKs is controlled by the balance between MAPK kinase and MAPK phosphatase activities. The latter is mediated by a subset of phosphatases with dual specificity (VH-1 family). Here, we describe a new member of this family encoded by the puckered gene of Drosophila. Mutations in this gene lead to cytoskeletal defects that result in a failure in dorsal closure related to those associated with mutations in basket, the Drosophila JNK homolog. We show that puckered mutations result in the hyperactivation of DJNK, and that overexpression of puc mimics basket mutant phenotypes. We also show that puckered expression is itself a consequence of the activity of the JNK pathway and that during dorsal closure, JNK signaling has a dual role: to activate an effector, encoded by decapentaplegic, and an element of negative feedback regulation encoded by puckered.     

High-frequency partial liquid ventilation in respiratory distress syndrome: hemodynamics and gas exchange

Partial liquid ventilation using conventional ventilatory schemes improves lung function in animal models of respiratory failure. We examined the feasibility of high-frequency partial liquid ventilation in the preterm lamb with respiratory distress syndrome and evaluated its effect on pulmonary and systemic hemodynamics. Seventeen lambs were studied in three groups: high-frequency gas ventilation (Gas group), high-frequency partial liquid ventilation (Liquid group), and high-frequency partial liquid ventilation with hypoxia-hypercarbia (Liquid-Hypoxia group). High-frequency partial liquid ventilation increased oxygenation compared with high-frequency gas ventilation over 5 h (arterial oxygen tension 253 +/- 21.3 vs. 17 +/- 1.8 Torr; P < 0.001). Pulmonary vascular resistance decreased 78% (P < 0.001), pulmonary blood flow increased fivefold (P < 0.001), and aortic pressure was maintained (P < 0.01) in the Liquid group, in contrast to progressive hypoxemia, hypercarbia, and shock in the Gas group. Central venous pressure did not change. The Liquid-Hypoxia group was similar to the Gas group. We conclude that high-frequency partial liquid ventilation improves gas exchange and stabilizes pulmonary and systemic hemodynamics compared with high-frequency gas ventilation. The stabilization appears to be due in large part to improvement in gas exchange.     

Effects of emoxipine and histochrome on lipid peroxidation and activity of serum MB-creatine phosphokinase in patients with ischemic heart disease during aortocoronary shunting]

Comparative study of the cardioprotective effect of antioxidants emoxipin and hystochrom was conducted in patients with chronic ICD during and after operation for aorto-coronary shunting. Both drugs effectively inhibited LPO activation and reduced the reperfusion damage to the myocardium recorded according to the release of MB-PCK into the blood. The new antioxidant hystochrom proved to be more effective. Its prevalent effect is associated with its higher antioxidant activity.     

Response to beta blockers in patients with neurocardiogenic syncope: how to predict beneficial effects

No definitive data are available about the possibility of predicting improvement in patients with neurocardiogenic syncope treated with beta blockers. Among 112 patients with syncope and a positive head-up tilt test (HUT), independent predictors for prevention of symptoms with beta blockers were determined using the Cox proportional hazards model. Each patient underwent HUT at 70 degrees for 20 minutes both in the drug-free state and during isoproterenol infusion given to increase the heart rate by at least 25%. Fifty-nine patients had a positive HUT during isoproterenol infusion and 53 in the drug-free state. All patients were then given esmolol infusion at 500 micrograms/kg per minute for 3 minutes followed by 300 micrograms/kg per minute maintenance dose. HUT was then repeated as previously described with or without isoproterenol, depending upon the initial positive response. Regardless of the response during esmolol, all patients were treated with metoprolol 50 to 100 mg twice daily. At follow-up, 36 patients experienced symptom relapse. Four of them had negative HUT on esmolol, whereas the remaining 32 did not respond to the acute infusion of esmolol. Only four patients with positive HUT on esmolol had a favorable response to metoprolol. Patients responding to metoprolol were older (55 +/- 12 years vs 42 +/- 15 years, P < 0.05). Response to metoprolol was predicted by a negative test on esmolol (P < 0.0001) and a positive HUT on isoproterenol (P < 0.001). Age older than 42 years was also associated with a higher likelihood of metoprolol success (P < 0.02). CONCLUSION: Acute challenge with esmolol infusion appears to be an accurate predictor of response to chronic beta blockers, together with age and a positive HUT during low-dose isoproterenol infusion.     

The use of nitrates and slow calcium channel blockers in the treatment of patients with ischemic heart disease and disorders of intraventricular conduction

Data are submitted on the condition of haemodynamics of greater and lesser circulation in patients with ischemic heart disease (IHD) presenting with the bundle-branch block. On the basis of the results from a combined clinical-instrumental investigation involving electro- and echocardiography the authors present the early objective quantitative criteria for the diagnosis of those haemodynamic shifts occurring in formation of the bundle-branch block. The blockade of the left bundle of His has a more pronounced effect on the greater circulation haemodynamics while that of the right one--on the lesser circulation. The authors give a comparative assessment of haemodynamic effects of a single dose of isosorbide dindtrate and nifedinin in the patients. Nitrosorbide and corinfar improve contractility of the left ventricle, decrease pulmonary hypertension and overloading of the right side of the heart.     

Influence of feed deprivation on ventilation and gas exchange in broilers: relationship to pulmonary hypertension syndrome

Fast-growing broiler chickens not uncommonly exhibit elevated pulmonary vascular resistance that leads to pulmonary hypertension and right ventricular failure. We tested the hypothesis that a distended gastrointestinal tract in these full-fed birds results in an abnormally low tidal volume and minute ventilation that could lead to pulmonary hypoxia, pulmonary arterial vasoconstriction, right ventricular failure, and ascites. Tidal volume, respiratory frequency, heart rate, percentage saturation of hemoglobin with oxygen (HbO2), O2 consumption, and carbon dioxide elimination were measured on fast-growing broiler chickens when full-fed and after 3, 6, and 9 h of feed deprivation. Tidal volume of full-fed birds was not abnormally low despite HbO2 values varying from above 80% to nearly 60%. Importantly, HbO2 was found to be markedly increased in the hypoxemic birds at and beyond a 3-h period without feed, despite a reduction in minute ventilation. This response was not caused by a decrease in O2 consumption. Thus, limitation of gas intake at the mouth was not the cause of the hypoxemia. The data suggest that feed deprivation results in an increase in parabronchial ventilation, possibly from improvement in aerodynamic valving, which would reduce pulmonary hypoxic vasoconstriction and right ventricular failure.     

The anesthesiological risk and treatment characteristics of patients with ischemic heart disease prepared preoperatively with beta-receptor blockers, calcium antagonists and nitro preparations

The anesthesiologic risk in ischemic heart disease (IHD) patients undergoing noncardiac surgery is determined by the duration of myocardial infarction sustained in the past, and the degree (severity) of stenocardia manifestations. Such risk is estimated as minimal within six months after myocardial infarction in the presence of stenocardia stabilization. In this contingent of patients the anti-ischemic therapy is proceeded with in both pre- and postoperative period. The role of beta-adrenergic blocking agents (propranolol, acebutolol, esmolol, sotalol) and calcium antagonists (nifedipine, diltiazem) in the prophylaxis against intraoperative myocardial ischemia, rhythm disorders and pathologic arterial pressure rise is definitely proved.