bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selectively N‐Protected Enantiopure 2,5‐Disubstituted Piperazines: Avoiding the Pitfalls in Solid‐Phase Fukuyama–Mitsunobu Cyclizations
Authors: Ottesen Lars K. , Olsen Christian A. , Witt Matthias , Jaroszewski Jerzy W. , Franzyk Henrik 
Published: February 2009

AbstractRobust protocol! A diverse array of piperazine scaffolds was obtained by a robust solid‐phase‐synthesis protocol involving multistep elaboration of a resin‐bound aziridine (see scheme). Microwave‐assisted on‐resin protectinggroup introduction and manipulation as well as intramolecular Fukuyama–Mitsunobu cyclization conditions were key features.magnified imageAn efficient solid‐phase route to ring‐substituted piperazines from O‐linked resin‐bound (S)‐aziridine‐2‐methanol is described. Regioselective microwave‐assisted aminolysis followed by intramolecular Fukuyama–Mitsunobu cyclization constitute the key features of the protocol. Simple piperazines and diazepanes were readily obtained without preceding N‐protection of the acyclic intermediate, whereas attempts to extend this protocol to chiral 2,5‐disubstituted piperazines failed. Modifications encompassing N‐carbamoylation prior to ring‐closure were therefore investigated. However, standard carbamoylating agents, for example, Fmoc‐Cl and Alloc‐Cl tended to give bis‐protected by‐products. Thus, novel microwave‐assisted solid‐phase N‐protection procedures were developed for efficient introduction of Fmoc, Boc and Alloc groups. The subsequent cyclization proceeded in moderate to excellent yields depending on the bulk of the side chain and type of N‐protecting group. This protocol readily provided novel cis‐ and trans‐2,5‐disubstituted piperazines displaying a variety of N‐protecting group patterns after further on‐resin manipulations. Also, unexpected by‐products obtained during these optimization studies were identified and characterized. This includes nosylated ureas arising from an alternative cyclization pathway. Finally, post‐cleavage oxidation gave access to the Fmoc/Boc‐protected α‐amino acid as well as the corresponding aldehyde. The chiral piperazines described in this work will enable construction of combinatorial libraries with a higher chemical diversity compared to those containing simple N,N′‐difunctionalized piperazines, often present in drug‐like compounds.
Copper(I) Zeolites as Heterogeneous and Ligand‐Free Catalysts: [3+2] Cycloaddition of Azomethine Imines
Authors: Keller Murielle , Sido Abdelkarim Sani Souna , Pale Patrick , Sommer Jean 
Published: February 2009

AbstractClicking in zeolites: Copper(I)‐exchanged zeolites proved to be practical and efficient catalysts for the cycloaddition of azomethine imines with alkynes, providing a convenient access to N,N‐bicyclic pyrazolidinone derivatives (see scheme). With high regioselectivity, 100 % atom economy, and convenient product isolation, this heterogeneously catalyzed version of the Dorn cycloaddition corresponds to click‐chemistry criteria.magnified imageCopper(I)‐exchanged zeolites were used as heterogeneous ligand‐free catalysts for [3+2] cycloaddition of azomethine ylides, which allows versatile, efficient, and highly regioselective synthesis of pyrazolone derivatives. These cheap and easy‐to‐prepare catalysts exhibit wide scope and compatibility with functional groups. They are very simple to use, easy to remove (by simple filtration), and recyclable (up to six times without loss of activity).
Comprehensive analysis of exertional ECG changes before and after oral propranolol
Authors: Hossack K. F. , Bruce R. A. , Kusumi F. 
Published: February 2009

AbstractIn 12 patients with symptomatic coronary heart disease and three normal persons, comprehensive analyses of the electrocardiographic changes associated with symptom‐limited upright exercise are made by computer analysis of the electrocardiogram recorded using a Frank XYZ lead system. This analysis provided a display of the 12 lead ECG, vectorcardiogram, polarcardiogram, and spatial cardiogram and measurements of spatial magnitudes of heart vectors. The effect of 40 mg of oral propranolol was assessed by repeating the exercise protocol 60‐90 min later. There is evidence that propranolol reduces the electrocardiographic features of myocardial ischemia. This reduction in myocardial ischemia correlates with reductions in pressure rate product and heart rate. The presence of infarct criteria with exercise is variable and not apparently influenced by propranolol.
Plasma lipoprotein patterns in patients hospitalized for coronary artery bypass surgery
Authors: Leszczynski D. E. , Cleveland J. C. , Kummerow F. A. 
Published: February 2009

AbstractPreoperative plasma samples from coronary artery bypass surgery patients were analyzed for relative levels of high‐density lipoproteins (HDL) and low‐density lipoproteins (LDL) in order to assess the HDL:LDL ratio as an indicator of risk for coronary heart disease. Fasting blood samples were drawn from bypass patients prior to surgery, and bypass patient mean plasma lipid data were compared with values from three other groups: randomly selected, newly admitted hospitalized patients; acutely ill student outpatients; and healthy hospital employees. Sudan Black B prestained plasma samples were electrophoresed on polyacrylamide gels, and HDL:LDL ratios were determined by densitometric gel scan and automatic peak integration. Of the four study groups, the bypass patient group had the lowest mean HDL:LDL ratio; the low ratios were due particularly to reduced levels of HDL2. Chemical analyses indicated that the bypass patient group also had lower mean HDL‐cholesterol and higher mean total cholesterol and triglyceride levels than the other groups. When group age and sex differences were taken into account, the bypass group, especially males, also had low ratios. The results also strongly indicated that stresses involved with illness and hospitalization unrelated to clinical coronary heart disease (CHD) can adversely affect lipoprotein patterns.
DPTI/STTI—An index of the myocardial oxygen supply/demand ratio?
Authors: Baller D. , Zipfel J. , Hellige G. 
Published: February 2009

AbstractThe DPTI/STTI (diastolic pressure‐time index/tension‐time index) ratio is applied as an indicator of myocardial ischemia particularly in cardiovascular and anesthesiologic care units. The validity of the DPTI/STTI ratio was examined in intact dogs with large variations of oxygen supply and demand. The correlation of DPTI/STTI to the directly measured oxygen supply/demand ratio was poor even under maximal coronary vasodilatation. Many data points were far below the critical DPTI/STTI values (reported previously) without occurrence of myocardial ischemia, failure, or edema. Therefore caution is necessary if the DPTI/STTI ratio is to be applied to humans.
Role of aminophylline in refractory heart failure: a comparison to the vasodilator sodium nitroprusside, the old and the new
Authors: Dibianco R. , Rosenfeld S. P. , Katz R. J. , Simpson A. G. , Fletcher R. D. , Singh S. 
Published: February 2009

AbstractAminophylline [(theophylline ethylene diamine (TED)] reportedly improves cardiac hemodynamics by lowering vascular resistances and increasing contractility. TED as used clinically has not been compared to the vasodilator sodium nitroprusside (NP). To assess the relative hemodynamic effects of these two commonly used agents, the following comparison was made.Ten patients with congestive cardiomyopathy in chronic refractory heart failure [New York Heart Association (NYHA) class IV] were studied. All patients demonstrated cardiomegaly by chest x ray and echocardiography (LVd= 6.3 ± 0.7 cm) and markedly abnormal hemodynamics during baseline observations (see Table I). Hemodynamic measurements at baseline were compared after TED infusion (mean blood level = 16±12 m̈g/m/TED) and during intravenous NP. No significant changes in heart rate occurred during either therapeutic intervention; a fall in mean arterial pressure of 10 mmHg (p<0.01) was observed during NP therapy; atrioventricular (AV) block with ventricular fibrillation was successfully treated in one patient after TED. Theophylline ethylene diamine demonstrated no detectable cardiac hemodynamic effects 60–90 min post infusion despite proven blood levels, whereas NP exhibited distinctly beneficial effects in this patient group.Previous studies demonstrating improved hemodynamics occurring with TED have been limited to the time of infusion or within the following 40 min, a time when TED blood levels are maximum and therefore closest to toxicity.The results of this study suggest that TED demonstrates no beneficial hemodynamic effects in refractory heart failure as early as 1 h after infusion despite blood levels in the therapeutic range.
Spectrum of heart muscle abnormalities related to alcoholism
Authors: Ahmed S. S. , Levinson G. E. , Fiore J. J. , Regan T. J. 
Published: February 2009

AbstractTo assess the diastolic and systolic performance characteristics of the left ventricle in alcoholism, three patient groups with a history of heavy alcohol consumption were compared with normal subjects. In those with symptoms related to chest pain or palpitations, heart size was normal on x ray. In groups III and IV, dyspnea was associated with varying degrees of cardiomegaly and a high prevalence of absent septal Q on the ECG.Despite substantial differences in physical findings, all three groups exhibited a significant increase in end‐diastolic pressure. Group I was distinguished by the fact that end‐diastolic volume was not increased but actually somewhat diminished. Groups II and III were characterized by a significant increase in end‐diastolic volume and tension. The latter was enhanced to a significantly greater extent in group III and was the most prominent hemodynamic abnormality in this group. A major change in the index of contractility, as well as in the rate of relaxation, occurred in group I. Further moderate depression of these indices was observed in the groups with enhanced diastolic volume. In the patients who had mitral regurgitation a more severe depression of left ventricular function was present in the alcoholic group than in a nonalcoholic control group, and was presumably due to the toxic effects of ethanol on the left ventricle.Thus, in those alcoholic patients who develop cardiac alterations, the earliest abnormality is characterized by diminished left ventricular compliance and a moderate contractility deficit without heart failure. In those who progress, end‐diastolic tension is substantially enhanced and further reduction in contractility indices is observed. The potential for reversibility is discussed.
Fungal endocarditis complicated by mycotic aneurysm of sinus of valsalva, interventricular septal abscess, and infectious pericarditis: Unique m‐mode and two‐dimensional echocardiographic findings
Authors: Incarvito J. , Yang S. S. , Papa L. , Fernandez J. , Chang K. S. 
Published: February 2009

AbstractA 26‐year‐old male with fungal aortic endocarditis is presented in whom unique M‐mode and two‐dimensional echocardiographic findings permitted a diagnosis of mycotic aneurysm of right sinus of Valsalva and ventricular septal abscess preoperatively. The aneurysm was excised, and the affected aortic and tricuspid valves were replaced with valve prostheses.
Correlation of false negative myocardial infarct scintigraphy with postmortem studies
Authors: Codini M. A. , Hawkins E. T. , Turner D. A. 
Published: February 2009

AbstractNegative myocardial infarct scintigrams with 99mtechnetium stannous pyrophosphate (99mTc‐PYP) were obtained in two patients with acute massive transmural infarct. Both patients died soon after scintigraphy. Because necropsy was performed within hours after death, we were able to correlate the distribution of the tracer within the acutely infarcted tissue with the myocardial scintigram. The clinical implication is that a single myocardial scintigram may be grossly inaccurate in detecting and quantifying infarct size. The scintigraphic findings should always be correlated with the electrocardiographic and enzymatic findings in evaluating patients with possible myocardial infarct.
Prinzmetal's variant angina induced only by alcohol ingestion
Authors: Sato A. , Taneichi Y. , Sekine I. , Okabe F. , Ueda A. , Takahashi M. , Ito T. , Su K.‐M. , Sada T. , Matsumoto S. , Ito Y. 
Published: February 2009

AbstractPrinzmetal's variant angina occurred in a 52‐year‐old man 10–11 h after the ingestion of alcohol, when blood levels of alcohol decreased almost to the zero level. Coronary arteriograms revealed significant narrowing in the left circumflex artery and the left anterior descending artery and minimal wall irregularity in the right coronary artery; however, both exercise and pharmacologic stress tests were negative. A withdrawal from an acute exposure to alcohol was discussed as a possible causative mechanism of the alcohol‐induced Prinzmetal's variant angina in this case.
Evaluation of technician audiovisual scanning of ambulatory electrocardiograph recordings utilizing the rapid oscillographic printout technique of validation
Authors: Dibianco R. , Katz R. J. , Fletcher R. D. , Bortz Costello R. , Gottdiener J. S. , Singh S. N. 
Published: February 2009

AbstractSummary: The accuracy of technician audiovisual scanning of ambulatory electrocardiographic recordings, coupled with physician review of demonstrative rhythm strips, was validated using the rapid oscillographic printout technique. Seventy‐five patients underwent 24‐h ambulatory electrocardiographic recordings which were routinely evaluated by audiovisual scanning for the highest hourly grades of ventricular ectopic activity (VEA). Printouts of three random hours per 24‐hours were then obtained (one hour per 8‐hour period). The total beat oscillographic printouts, written at 120 × real time, were then graded by at least two authors and compared to the results of audiovisual scanning. Hourly VEA grades were: 0 = no ventricular ectopy; 1 = ≤ 10 unifocals; 2 = > 10 unifocals; 3 = ≤ 10 multifocals; 3A = > 10 multifocals; 4 = couplets; 5 = triplets or salvos. VEA grades were further grouped into high grade (2, 3A, 4 or 5) and low grade (0, 1, or 3) categories. The comparison of rapid oscillographic total beat printout to technician audiovisual scanning coupled with physician review of ambulatory electrocardiographic data produced the following conclusions: (1) The highest hourly VEA grade was exactly identified 65% (146/225) of the time, or was closely approximated (identified within one grade of the highest VEA grade) 80% (181/225) of the time. Excluding errors that were secondary to overlooking rare electrical events, technicians successfully identified 88% (199/225) of hours for the highest VEA grade; (2) patients with high grade and low grade VEA were identified with an accuracy of 91% (51/55) and 95% (19/20), respectively; (3) technician reports which combined each of the three random hours per patient were more predictably accurate when positive for high grade VEA (98% of patients, 50/51) than for low grade VEA (79% of patients, 19/24); p < 0.05); (4) “underreading” errors in audiovisual scanning were almost six times more frequent as those of “overreading” (67 vs. 12 instances, respectively), with a failure to recognize low frequency electrocardiographic events as the most prevalent type of error. This study demonstrates the use of the rapid oscillographic printout technique for the display of ambulatory electrocardiographic data in hard copy compressed form which was successfully used to validate technician performance in the audiovisual scanning of ambulatory ECG recordings.
A new atrial transseptal pacing electrode
Authors: Udall J. A. 
Published: February 2009

AbstractSummary: The atrial septum provides a convenient structure to which a transvenous electrode can be attached securely. The Brockenbrough cardiac catheterization technique has been used to gain access to the left atrium. A new electrode has been fabricated which can be inserted into the left atrium through the lumen of a Brockenbrough catheter. The electrode is composed of a stainless steel coil attached inside the proximal end of a platinum cylinder at the cardiac terminal. Three Elgiloy wires, having a wing configuration, are attached inside the distal end of the platinum cylinder. The coil and cylinder are insulated by silicone rubber and the metallic surface area of the distal electrode tip equals 5 mm2. This electrode has been implanted without difficulty or complications in five patients with tachycardia‐bradycardia syndrome.
The treatment of hypertension by labetalol‐a new alpha‐ and beta‐adrenoreceptor blocking agent
Authors: Stern N. , Teicher A. , Rosenthal T. 
Published: February 2009

AbstractSummary: A new alpha‐ and beta‐blocking agent, labetalol, was used to treat 50 hypertensive patients, 34 of them with refractory hypertension. A significant reduction in hypertension was achieved with relatively few adverse reactions. The combination of alpha and beta blockers in labetalol with their mutually opposing characteristics offers an interesting and promising approach to the control of hypertension.
A clinical evaluation of sustained release metoprolol durules in the treatment of angina pectoris
Authors: Ccomerford M. B. , Besternabm E. M. M. 
Published: February 2009

AbstractSummary: A clinical comparison of the sustained release form of metoprolol, consisting of a 200 mg metoprolol durule, with 100 mg conventional metoprolol twice daily, has been carried out to assess the therapeutic control of ten patients with stable angina pectoris. Objective measurements of heart rate, blood pressure, and ECG recordings were assessed during exercise on a bicycle ergometer. Ten patients completed the 8‐week double‐blind study. There were similar changes in heart rate and blood pressure at rest and during exercise, both at 2h and at 12 and 24 h postdose. Although similar exercise tolerance was achieved on both regimes, there was significantly less ST‐segment depression at 24h post durule, in comparison with the 12h post conventional metoprolol reading, suggesting that metoprolol durules produce a more effective reduction in the degree of myocardial ischemia.
Thrombolytic therapy for a thrombosed bjork‐shiley tricuspid valve prosthesis
Authors: Hellestrand K. J. , Morgan J. J. , Chang V. P. 
Published: February 2009

AbstractSummary: A 67‐year‐old man in whom mitral and tricuspid Bjork‐Shiley tilting disc prostheses had been implanted 68 months previously presented with thrombotic obstruction of his tricuspid prosthesis. Initial cardiac catheterization demonstrated a significant transprosthetic tricuspid diastolic gradient (9.5 mmHg) with a calculated prosthetic valve orifice area (0.62 cm2) indicating a critical degree of stenosis. The resting cardiac index was markedly reduced (1.5 l/m2/min). Following an intravenous infusion of streptokinase for 66 hours, repeat cardiac catheterization revealed a 50% reduction in transprosthetic diastolic gradient across the tricuspid valve (4.7 mmHg), a greater than fourfold increase in prosthetic valve orifice area (2.87 cm2) with a normal resting cardiac index (3.1 1/m2/min).
Acute myocardial infarction in patients with normal coronary arteries after acute ethanol intoxication
Authors: Moreyra A. E. , Kostis J. B. , Passannante A. J. , Kuo P. T. 
Published: February 2009

AbstractThree cases are presented where acute myocardial infarction occurred in young individuals after an episode of heavy alcohol intake. Subsequent coronary arteriograms demonstrated normal coronary arteries. Several mechanisms by which acute ethanol intoxication might precipitate myocardial infarction are discussed. To our knowledge, no similar cases have been reported.
Echocardiographic diagnosis of an unusual anterior mediastinal mass
Authors: D'Cruz I. A. , Chiemmongkoltip P. 
Published: February 2009

AbstractX‐ray chest and CAT scan suggested an anterior mediastinal mass in a girl who had prominent left parasternal pulsations. M‐mode and two‐dimensional echocardiography demonstrated an extracardiac fairly rigid cystic mass between right ventricle and chest wall, which proved to be a cystic chondroma arising from the fourth left costal cartilage.
Chronic tocainide therapy for refractory high‐grade ventricular arrhythmias
Authors: Haffajee C. I. , Sacks G. M. , Alpert J. S. , Howe J. P. , Ockene I. S. , Paraskos J. A. , Dalen J. E. 
Published: February 2009

AbstractTocainide, an oral analog of lidocaine, was evaluated as a long‐term antiarrhythmic agent in 21 patients with symptomatic complex ventricular ectopic activity (10 with hemodynamically significant ventricular tachycardia) refractory to currently available antiarrhythmics singly, and in combination for periods of 3 days to 35 months (mean 13.6 months). Tocainide appeared to be an effective and safe agent for the control of these refractory symptomatic ventricular arrhythmias in 14 of the 21 patients (66%). Minor central nervous system and gastrointestinal side effects were present in most of the patients, usually early on in therapy, and only precluded long‐term use in 2 patients. Furthermore, lidocaine responsiveness was a good predictor of to‐cainide effectiveness in this group of patients. Tocainide precipitated atrioventricular (A‐V) block in one patient with pre‐existing A‐V nodal disease; two patients developed a skin rash while on tocainide therapy. These two patients had previously developed lupus‐like syndromes and skin rashes while on procainamide. The ANA titers had been falling in these two patients while on tocainide, and in one of these patients with true systemic lupus erythematosus, rechallenge with tocainide failed to produce skin rash. Tocainide's long plasma half‐life and high oral bioavailability permit an 8‐h regime. We conclude that tocainide is an effective, safe antiarrhythmic agent with tolerable side effects.
Submitral atheromatous lesions in monkey and man
Authors: Feinstein S. , Pick R. , D'Cruz I. , Abrahams C. , Liswood‐Strauss A. 
Published: February 2009

AbstractPosterior submitral recess (PSMR) calcification is a common autopsy finding in elderly people, but its pathogenesis is undetermined. In this communication we show that, in part at least, the PSMR changes at autopsy are atheroma‐like with lipid around the sclerosis and calcific deposits. These changes in the PSMR showed a statistically significant correlation with the presence of hypertension and with an autopsy finding of severe coronary atherosclerosis. We showed, for the first time, that similar fibrosis and lipid deposition in the PSMR can be produced in high‐fat, high‐cholesterol fed macaque monkeys (Macaca arctoides) with or without concomitant experimentally produced hypertension. It is concluded that changes in the PSMR in monkeys and man are strongly related to atherosclerosis and hypertension.
Flecainide‐induced aggravation of ventricular tachycardia
Authors: Hohnloser S. , Zeiher A. , Hust M. H. , Wollschläger H. , Just H. 
Published: February 2009

AbstractFlecainide acetate is a new class I antiarrhythmic agent which slows atrial, A‐V nodal and ventricular conduction velocity, and prolongs refractoriness of these structures (Borchard et al., 1982; Hodess et al., 1979). Recent studies with oral flecainide therapy suggested its high potential for suppression of ventricular tachycardia in humans (Anderson et al., 1981; Duff et al., 1981; Hodges et al., 1982). Its favorable pharmacokinetics with an average plasma half‐time of about 20 hours allows in most patients twice daily dosing (Duff et al., 1981). Usually, the drug seemed to be well tolerated and side‐effects, such as blurred vision, could be resolved with smaller but still effective doses (Duff et al., 1981). Actually, the ideal antiarrhythmic agent which represents a high degree of effectiveness, a low level of toxicity, a wide therapeutic range, and a prolonged antiarrhythmic action does not exist (Dreifus and Ogawa, 1977). In this report we describe a patient with flecainide‐induced aggravation of ventricular tachycardia necessitating resuscitation because of severe hemodynamic deterioration.