Safety of outpatient cardiac catheterizations

Since 1979 most of the cardiac catheterizations at the investigators' institution have been performed as outpatient procedures. All cardiac catheterizations performed over a 66-month period were analyzed. A total of 3,071 outpatient cardiac catheterizations (83% of all cardiac catheterizations) were performed. The percutaneous femoral technique was used in 98% of the procedures. Most patients (79%) had both right and left-sided cardiac catheterization and coronary angiography, which showed significant coronary artery disease (70.4%). Only 13.6% of the study results were normal. Thirty-four patients (1.1%) had major complications, including 4 deaths (0.13%). Seventy patients (2.3%) were admitted for observation only. More than 96% of all patients did not have a major complication and were discharged the same day. Thus, outpatient cardiac catheterization can be performed safely, with a potential reduction in hospital costs and better utilization of medical beds.

Exposed tyrosine residues of lambda cro repressor protein evidenced by nitration and photo CIDNP experiments

The tyrosine residues of lambda cro repressor were partially nitrated with tetranitromethane under mild conditions. After digestion by Achromobacter protease I, the extent of nitration was determined by HPLC and amino acid analysis. Tyr 26 was most easily nitrated and Tyr 51 followed it. Tyr 10 was resistant to nitration. By comparison of the proton magnetic resonance spectrum of the partially nitrated cro protein with the above result, the aromatic proton resonances of the tyrosine side chains could be assigned to individual tyrosine residues. The extent of nitration is parallel to the accessibility to a flavin dye as measured by photo CIDNP (chemically induced dynamic nuclear polarization).

Identification of proliferin mRNA and protein in mouse placenta

Proliferin is a recently described, prolactin-related protein whose mRNA appears in several murine cell lines during active growth. We have surveyed a number of mouse organs or tissues for the presence of mRNAs that hybridize to cloned proliferin cDNA. Of the tissues tested, only the placenta yielded proliferin-related mRNA. This placental RNA is about 1 kilobase in length, increases sharply between days 8 and 10 of pregnancy, and then gradually declines through day 18. It is more abundant in RNA extracted from the fetal, compared to the maternal, part of the placenta. From a cDNA plasmid library prepared from poly(A)+ placental RNA, two types of proliferin-related clones were isolated, differing in intensity of hybridization to proliferin cDNA. By nucleotide sequence analysis, a strongly hybridizing clone was found to be nearly identical to the proliferin cDNA clone isolated from a library prepared from mRNA of a growing mouse fibroblastic cell line. Using an antiserum prepared against a synthetic proliferin fusion protein, we show that proliferin is secreted as a glycoprotein by minced placental tissue and that it differs from mouse placental lactogen. We conclude that proliferin is a placental hormone that is synthesized in certain mouse cell lines during active growth. Its function during pregnancy and during the growth of cultured cells is presently unknown.

Photo CIDNP study on the complex formation of lambda cro protein with OR3

A photo CIDNP spectrum of lambda cro repressor protein showed that one of the three tyrosines and His 35 are quite accessible to the photosensitive dye. For the remaining two tyrosine residues one is slightly accessible, but the other is inaccessible. In comparison with the result of differential nitration at tyrosine side chains followed by the peptide analysis, it can be concluded that Tyr 26 is mostly exposed and Tyr 51 is slightly exposed on the surface of the cro dimer. On the addition of OR3 17mer, His 35 and Tyr 26 are no longer accessible to the dye, which indicates that they are involved in interaction. However, a similar phenomenon was observed by adding CAP binding site 22mer. The interaction mechanism will be discussed.

Abolition of the negative endocochlear potential as a consequence of the gentamicin-furosemide interaction

The DC endocochlear potential and the AC cochlear potential in response to a 4 kHz tone were recorded in pigmented guinea pigs before and during ototoxic damage induced by sequential administration of the aminoglycoside antibiotic, gentamicin, and the loop diuretic, furosemide. Within 4 h significant diminution of the amplitude of the AC cochlear potential was accompanied by an almost complete abolition of the negative diffusion potential revealed by either furosemide administration or terminal anoxia. Thus, one of the effects of this interaction appears to involve a reduction in the potassium permeability of the cochlear partitions.

Seroimmunity to poliomyelitis in hospital personnel

Neutralizing antibody titers to poliovirus type 1, 2 and 3 were examined in paired serum specimens obtained from 43 female hospital personnel and laboratory workers at Veterans General Hospital. Before vaccination, 23.2% of those studied did not have neutralizing antibodies to one or more types of poliovirus, and 4.6%, 13.9% and 7.0% lacked serum neutralizing antibodies to poliovirus type 1, 2 and 3, respectively. In a comparison of the serological responses evoked by oral poliovirus vaccine in the same persons, a striking difference in antibodies was shown in the geometric mean titers and no lack of antibodies was found after oral poliovaccine immunization. Therefore immunization with oral poliovirus vaccine should be considered in the future as to improved protection for such high risk people.

Carcinogenic agents in cigarette smoke and the influence of nitrate on their formation

The nitrate level of a nonfilter reference cigarette was elevated from 0.52% to 1.2, 1.8, 2.4 and 3.05%, respectively, by addition of sodium nitrate. Data from the mainstream smoke analyses of these cigarettes were compared. Yields of carbon monoxide and carbon dioxide were not significantly altered as a result of nitrate elevation. Tar, nicotine, benzo[a]pyrene (BaP) and catechol in mainstream smoke were reduced while yields of nitrogen oxides (NOx), volatile N-nitrosamines (VNA) and tobacco-specific N-nitrosamines (TSNA) were significantly increased. On the basis of previous bioassays with smoke condensates from high-nitrate cigarettes, it was expected that the cutaneous tumorigenicity of these tars would be reduced due to lower levels of BaP (and other carcinogenic PAH) and catechol. However, the total carcinogenic potential of whole smoke from high nitrate cigarettes is considered by us to be significantly increased due to the elevated yields of Nox, VNA and TSNA. The nitrosamines are regarded as a major group of carcinogens in tobacco smoke; the nitrogen oxides are the most important precursors for the endogenous formation of N-nitrosamines upon smoke inhalation. The findings of this model study support the recommendation that the nitrate content of tobacco products should be reduced.

Molecular interaction between riboflavin and salicylic acid derivatives in nonpolar solvents

The interaction of riboflavin-2',3',4',5'-tetrabutyrate (I) with salicylic acid (II), aspirin (acetylsalicylic acid, III), and salicylamide (IV) has been spectroscopically investigated to determine the binding mechanism. NMR and absorption spectra were measured in nonpolar solvents. The association constant K of the formation of complex was calculated from the absorption spectra. Compounds I and II form a 1:1 cyclic hydrogen-bonded dimer through the N-3 proton and the C-2 carbonyl oxygen of the isoalloxazine ring, and the carboxylic hydroxyl proton and carbonyl oxygen of II. Compounds I and III form a 1:1 cyclic hydrogen-bonded dimer by the same mode. Compound IV forms a 1:1 cyclic hydrogen-bonded dimer with I through the N-3 proton and the C-2 carbonyl oxygen of the isoalloxazine ring, and the amino proton and the carbonyl oxygen of IV. Salicylates produce marked changes in the absorption spectra of I. These spectral changes are attributed to the formation of the hydrogen-bonded dimer. It appeared that the strongest complex was formed with salicylic acid, a weaker one with aspirin, and an even weaker one with salicylamide.

On the formation of the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone during smoking

Tobacco-specific N-nitrosamines (TSNA) are the most abundant carcinogens identified in tobacco and its smoke. Reducing their levels in tobacco products and especially in cigarette smoke is, therefore, a primary goal towards minimizing the carcinogenic burden of the tobacco consumer. This study delineates the mechanisms of formation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), the most powerful of the carcinogenic TSNA during cigarette smoking. It demonstrates, by means of radiolabeled tracer compounds that 6.9-11.0% of the NNK formed in tobacco during the curing process transfers into the mainstream smoke. This constitutes 26-37% of the NNK present in the smoke. Addition of [methyl-14C]-nicotine to cigarettes, prior to smoking, led to the finding that 0.001% of nicotine in the cigarette column appears in the smoke as NNK. Thus, 63-74% of NNK in smoke is formed during smoking. NNK yield in the smoke was independent of nitrate content of the tobacco. These data serve to devise methods of reducing TSNA in smoke.

Interaction between flavins and alcohols

The effect of alcohols on the spectral properties of riboflavin derivatives in non-polar solvent was studied by various spectroscopic methods in order to support the view point that alcohol may directly interact with the isoalloxazine moiety of FAD and enhance the catalytic activity of D-amino acid oxidase (DAAO). The most likely association complex between alcohol and riboflavin is 1 : 1 stoichiometric complex through the 3-N imino and the 2-C carbonyl groups of the isoalloxazine ring and the hydroxyl group of alcohols. It appears that methanol has a larger association constant than any other alcohols, and the association constant decreases with the increase in carbon number and with the steric requirement of the alkyl group of alcohols.

Three-dimensional digital subtraction angiography

A dye-edge tracking algorithm was used to determine the corresponding points in the two images (anterior-posterior and lateral) of the digital subtraction biplane angiography. This correspondence was used to reconstruct three-dimensional images of cerebral arteries in a dog experiment and a clinical observation. The method was tested by comparing the measured image of oblique view to the computed reconstructed image. For the present study, we have developed three new algorithms. The first algorithm is to determine the corresponding dye-edge points using the fact that the density of contrast media at the moving edge shows the same changing pattern in the two projection views. This moving pattern of dye-edge density is computed using a matching method of cross correlation for the two sequential frames' dye density. The second algorithm is for simplified perspective transformation, and the third is to identify the corresponding points using a complementary method for locating the approximate points on the small vessels. The present method can be applied to compute the velocity of blood flow using the dye-edge displacement and the three-dimensional distance data.

Late replication and recombination in the vegetative pool of T4

The rates and extents of replication are the same for all members of the vegetative pool, whether already residing (progeny) or newly entered (superinfecting). Thus, no member of the pool is sequestered in a replicative complex. Amber N82 infections of nonpermissive host result in extensive breakdown of phage DNA. The extent of fragmentation observed depends on the multiplicity of infection and whether phage ligase is present. Hence, parental DNA suffers single-strand nicks which can be repaired by ligase only if recombination does not interfere. The physiological role of ligase in compensating for such nicks is reemphasized. Superinfecting genomes recombine very rapidly with progeny molecules whose combined lengths are approximately six times that of the superinfecting genomic fragment. The superinfecting phage does not replicate before recombining. Therefore, the lack of replication poses no barrier to efficient recombination.

Noninvasive assessment of left ventricular function from the mitral valve echogram. Relation of final anterior mitral leaflet closing velocity to peak dp/dt and aortic velocity

Since final mitral valve (MV) closure and aortic ejection velocity are mediated by the same forces in early left ventricular (LV) contraction, the rate of final MV closure (BC slope) should reflect LV performance. We first verified whether peak final closing velocity (ds/dt) of the anterior MV leaflet (AMVL) is related to peak aortic ejection velocity (V) and LV dp/dt in 18 open-chest dogs. We then checked the validity of the relations in man. Our approach was to measure peak ds/dt, peak aortic acceleration (dV/dt) and peak LV dp/dt using electronic differentiation of analog signals of the AMVL echogram, V and LV pressure. In dogs, resting ds/dt averaged 26.9 +/- 9.0 (SD) cm/sec and changed significantly (P less than 0.001) after isoproterenol, propranolol, coronary ligation and aortic cross-clamping. We found good (P less than 0.001) correlations between ds/dt and V (r = 0.82), dV/dt ( r = 0.67) and dp/dt (r = 0.73). In man, resting ds/dt averaged 25.5 +/- 1.6 cm/sec in six normals. In 40 patients with coronary artery disease, restind ds/dt was lower (15.7 +/- 4.4 cm/sec; P less than 0.001) in the 19 with resting LV end-diastolic pressure (LVEDP) greater than 12 mm Hg. Resting ds/dt correlated closely with V (r = 0.82, N = 10), dp/dt (r = 0.93, N = 6), resting LVEDP (r = -0.67, N = 40), angiographic ejection fractions (r = 0.62, N = 40) as well as manually obtained BC slopes (r = 0.93, N = 40). Thus, final MV closing velocity provides a useful and simple means for the objective noninvasive assessment of LV performance.

Long-term survival after tricuspid valve replacement. Results with seven different prostheses

The experience with tricuspid valve replacement (TVR) with seven different prostheses, alone or combined with replacement of other valves, in 73 patients (64 rheumatic and nine nonrheumatic) between 1964 and March, 1975, at the University of Alberta Hospital has been reviewed. Early and late mortality rates in rheumatic patients were 41 and 23 percent, respectively (36 percent being alive after a mean of 5.6 years), compared to 33 and 11 percent, respectively, in the nonrheumatic patients (56 percent being alive after a mean of 2 years). Of all survivors, 88 percent were functionally improved. Among the rheumatic patients: (1) 88 percent had organic tricuspid disease; (2) of the 39 patients with tricuspid insufficiency who underwent corrective mitral surgery 7 years before TVR, the tricuspid insufficiency had progressed over the 7 years; (3) the number of patients with tricuspid insufficiency had increased (39 versus 59) over the same 7 year period; (4) a high early mortality rate was encountered in those who were preoperatively in New York Heart Association (N.Y.H.A.) Class IV, or who had cardiomegaly, or pulmonary hypertension, or poor ventricular function, or organic disease, or reoperation; (5) the percentages of survivors with different prostheses were: Starr-Edwards, 31 percent; Beall-Surgitool, 14 percent; Kay-Shiley, 46 percent, Björk-Shiley, 50 percent; Lillehei-Kaster, 100 percent; Cutter-Smeloff and Wada-Cutter, nil. Among the nonrheumatic patients, two with the Cutter-Smeloff, two with the Beall-Surgitool, and one with the Lillehei-Kaster were alive after 14, 37, and 15 months, respectively. Among all survivors of TVR, late thrombus and pannus developed on both ball and disc prostheses (Starr-Edwards, two; Cutter-Smeloff, one; Lillehei-Kaster, one). These findings suggest that TVR should be performed earlier in rheumatic patients to reduce the operative mortality rate and that the Lillehei-Kaster prosthesis is probably most suitable for TVR.

Application of step-wise discriminant analysis and Bayesian classification procedure in determining prognosis of acute myocardial infarction

A retrospective study was carried out to assess the feasibility of computer-assisted prognostication by discriminant analysis and the Bayesian classification procedure based on clinical information collected on patients with acute myocardial infarction. The overall accuracy was 94.2% in predicting hospital death but the prediction of late death after discharge was less accurate. It was found that not all of the 44 variables used for analysis were necessary to reach the same level of predictive accuracy--16 to 20 variables would result in almost the identical prediction. The Bayesian classification procedure was applied to estimate probabilities of individual patients belonging to the different prognostic categories.

Echocardiographic measurement of cardiac output using the mitral valve and aortic root echo

The current echo method for measuring cardiac output (CO) has various technical limitations and is based on the assumptions that the left ventricle is not dilated and that it contracts uniformly. We have taken a different approach to measuring CO by echo: CO = cross-sectional area of aortic root X left ventricular ejection time X mean aortic flow velocity X heart rate. Using the Fick method, 34 measurements of CO were made in patients with normal aortic and mitral valves, with simultaneous echo recordings from the aortic and mitral valves. The systolic closure slope of the anterior mitral valve leaflet was assumed to represent the mean aortic flow velocity. CO by Fick and the proposed echo method correlated well, both in patients with (r = 0.94) and those without (r = 0.87) asynergy and the overall correlation was strong (r = 0.90). Using the conventional echo and Fick methods, a much weaker association was found between the two measurements in those patients with asynergy (r = 0.44) as opposed to those without asynergy (r = 0.77).

Abolition of ischemic response to atrial pacing following aortocoronary bypass surgery

To determine the effect of successful aortocoronary bypass surgery (ACBS) on left ventricular (LV) function, the ischemic response to right atrial pacing (RAP) was studied in 22 angina patients before and 3.8 +/- 1.1 months after surgery. All patients were free of angina after ACBS and had at least one patent graft. Before ACBS, RAP induced angina in 15 patients (Group 1) but not in 7 patients (Group 2). After ACBS, no patient had angina with RAP despite the increased maximum rate of pacing. Post-pacing LV end-diastolic pressure (LVEDP) after ACBS decreased in Group 1 from 25 +/- 6 to 15 +/- 6 mm Hg (P less than 0.01), but not in Group 2. Changes in ejection fraction, cardiac output, resting LVEDP, or LVEDP after LV angiography were not significant in either group and were therefore not useful in evaluating the result of ACBS. However the ischemic response to right atrial pacing was abolished by successful aortocoronary bypass surgery, suggesting improved myocardial perfusion during stress.

False left ventricular aneurysm as a complication of open heart surgery

A false aneurysm developed at the site of left ventricular venting in an 8-year-old boy who had undergone aortic valve commissurotomy under cardiopulmonary bypass. The diagnosis was made by clinical examination and chest radiography and confirmed by left ventricular cineangiography. The aneurysm was successfully resected.

Long-term survival after isolated replacement of mitral valve with ball-valve prosthesis

In 111 patients whose diseases mitral valve was replaced with a ball-valve prosthesis the actuarial survival rate, including the hospital mortality of 10.8%, was 66% after 5 years and 59% after 8 years of follow-up. This suggests that in patients with moderate or severe symptoms due to mitral valve disease, replacing the valve can prolong life. However, in patients with no cardiac symptoms or with sinus rhythm and mild symptoms, it is doubtful that mitral valve replacement can prolong life, for the prognosis in these patients is favourable without operation.

Clinical echocardiography - an overview

Echocardiography is a new diagnostic technique for noninvasive assessment of the size, structure and function of the heart, using pulsed ultrasound. The physical principles underlying the generation of the ultrasonic signal for diagnostic use and the three modes (A, B and M) of displaying the reflected "echo" signal are briefly discussed. A full echographic study of the heart includes evaluation of the dimensions and patterns of movement of its various structures and chambers. The normal anatomic relations and echographic appearances of these structures and the changes they undergo in some of the more commonly recognized clinical conditions are described. Assessment of output and contractile behaviour of the left ventricle and recognition of various congenital heart defects are two of the more recent applications of this technique. Two-dimensional sector and multiscanning devices permit several areas of the heart to be visualized simultaneously in "real time".

Long-term survival after aortic valve replacement using Smeloff-Cutter prosthesis

The long-term prognosis of 187 consecutive patients who received single aortic valve replacement using Smeloff-Cutter prosthesis was studied. Of the 163 patients who survived the operation, a long-term follow-up (up to eight years) was obtained in 153 patients (95%). A total of 34 patients (22%) died during the follow-up period. Including the hospital mortality, the actuarial survival rate of our patients with Smeloff-Cutter prosthesis was 0.69 after the fifth year and 0.611 after the eighth year of follow-up. This is similar to the actuarial survival rate of patients with Starr-Edwards prosthesis but it appears significantly better than the expected survival rate of symptomatic patients with aortic stenosis treated without surgery. Thus, this result supports the contention that aortic valve surgery in properly selected patients can prolong life expectancy in addition to relieving symptoms in patients with aortic valve disease. The majority of surviving patients reported to have improved (88%) since the operation and to be symptom free (82%).

Ruptured aneurysms of sinuses of Valsalva

At least one additional cardiac lesion was present in 18 consecutive patients with ruptured aneurysms of the sinuses of Valsalva who were investigated between 1956 and 1973 at the University of Alberta Hospital. Clinical diagnosis was made in 78% (14/18) of the patients. Confirmation at cardiac catheterization, operation or autopsy was obtained in all but one. The main sites of rupture were the right ventricle (seven cases), right atrium (five) and left ventricle (five). Fifty percent (9/18) are alive and well following prompt operative repair, an average of 8.2 years later (range, six months to 15 years). Replacement of the aortic valve was associated with a high mortality (50% early, 13% late, total 63%) which could be explained by the higher operative risk in this group of very ill patients. Eight patients (44.4%) had had bacterial endocarditis prior to presentation and this may have played a significant role in the rupture of the sinus of Valsalva aneurysm.

Effects of nitroglycerin on left ventricular volumes and wall tension in patients with ischaemic heart disease

Since the dimensions of the ventricles are related to both myocardial tension and myocardial oxygen consumption (MVO2), the effects of nitroglycerin on the left ventricular volumes and left ventricular haemodynamics were studied in patients with ischaemic heart disease. The ventricular volumes were estimated using the constant infusion technique (indocyanine green) of Shaffer (1964). Sublingual administration of nitroglycerin (0.6 mg.) resulted in a significant reduction in cardiac output (27%), mean systolic pressure (21%), left ventricular end-diastolic pressure (63%), stroke volume (27%), left ventricular end-diastolic volume (26%), and left ventricular work (41%). Both calculated circumferential myocardial force (40%) and the myocardial tension (33%) decreased during systole, while the pressure-time index decreased by 27%. A similar decrease was also found in the contractile element work (42%), and mean circumferential fibre shortening rate (22%). Thus, this study has shown that the major determinants of MVO2, i.e. myocardial wall tension, the velocity of contraction, and contractile element work, decrease significantly after administration of nitroglycerin.

Hemodynamic changes following correction of severe aortic stenosis using the Cutter-Smeloff prosthesis

Twelve patients with pure or dominant stenosis were studied before and after aortic valve replacement (Cutter-Smeloff). The changes in cardiac output and A-V O2 difference were small and insignificant, but exercise stroke volume increased from 72 to 96 ml after the surgery. The aortic peak systolic gradient was 92 +/- 29 mm Hg before and 4 +/- 9.8 mm Hg after surgery. The PA wedge pressure, taken as a measure of the LV diastolic pressure, decreased from 18 mm Hg to 12 mm Hg at rest and 30 mm Hg to 16 mm Hg on exercise. The PA pressures also decreased from 37/18 (mean, 26) to 28/11 (17) mm Hg at rest, and 61/31 (43) to 41/17 (27) mm Hg on exercise, but the PA and PA wedge pressures maintained their tendency to increase in a linear manner with oxygen consumption (Vo2) on exercise after surgery. As a result of decreased wedge pressure, the pulmonary vascular resistance also decreased significantly afterward. The adequacy of cardiac output at rest and on exercise expressed by cardiac output as the linear function of Vo2 improved toward the normal (values before operation, CO = 2.78 + 0.0069 Vo2, r = 0.84; after operation, CO = 3.80 + 0.0062 Vo2, r = 0.91). The exercise factor (delta CO/delta Vo2) or the regression coefficient, however, was similar before and after surgery. The hemodynamic result was satisfactory although some abnormalities of the left ventricular function persisted after operation.

Malfunction of the mitral valve prosthesis (Cutter-Smeloff). Clinical and hemodynamic observations in three cases

Three cases of intermittent obstruction of the mitral prosthesis (Cutter-Smeloff) due to ball variance have been reported. The typical findings were marked variation in the arterial pulse and the intensity of the mitral closing sound and intermittent absence of the opening click. The phonocardiography revealed varying intervals from aortic closing sound to the opening click (A 2 - OC interval). Hemodynamic studies revealed fluctuating aortic and pulmonary artery wedge pressures in spite of normal sinus rhythm, due to impaction of the ball into the prosthetic ring, opening only with severe elevation of the left atrial pressure. At operation, the balls showed yellowish discoloration, but no disruption of sutures nor thrombosis of the prosthesis was found. The incidence of this phenomenon was 9% with the Cutter-Smeloff mitral prosthesis, but no such case was seen among patients with the Starr-Edwards mitral prosthesis.