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Biomedical subjects

C W Frank

Publications and source records attributed to C W Frank.

At least 37 records · Page 2Linked to original sources
PubMed1977

Ventricular premature beats and mortality after myocardial infarction.

To assess the role of ventricular premature beats in influencing mortality of coronary patients, 1739 men with prior myocardial infarction were monitored for ectopic activity for one hour at a standard base-line examination, and followed for mortality for periods up to four years (average, 24.4 months). Analyses of survival taking into account other important prognostic variables establish that the presence of complex premature beats (R on T, runs of 2 or more, multiform or bigeminal premature beats) in the monitoring hour is associated with a risk of sudden coronary death three times that of the men free of complex ventricular premature beats. The corresponding risk of death from any cause is twice that of men without such complex beats in the hour. These arrhythmias make an independent contribution to increased risk of death that persists over the length of this observation period.

Adult↗
PubMed1976

Circular dichroism spectra of tetracycline complexes with Mg+2 and Ca+2.

The study of Ca+2 and Mg+2 complexes of tetracycline in buffered solution was undertaken to determine their stoichiometry and the chelation sites. Circular dichroism was used to follow complex formation. Modified tetracyclines, in which potential complexation sites were blocked, were used to determine the participation of particular sites in complexation. Calcium formed a 2:1 metal-ion to ligand complex, while the magnesium complex formed at a 1:1 ratio. Formation of the calcium complex involved addition of one metal ion to the C-10, C-11 site with subsequent addition of a second metal ion at the C-12, C-1 site. The magnesium chelate occurred at the C-11, C-12 beta-diketone site.

Calcium↗
PubMed1976

Potentiometric and spectral investigations of anhydrotetracycline and its metal-ion complexes.

The interaction of various metal ions with anhydrotetracycline was investigated. A comparison of the UV-visible and fluorescence spectral characteristics of anhydrotetracycline and its metal-ion complexes with a number of modified anhydrotetracyclines in the presence of metal ions suggested that the C-11 oxygen was involved in metal-ion binding. Secondary binding was observed in the A-ring by circular dichroism when the primary site was blocked.

Chelating Agents↗
PubMed1975

Dehydration of tetracycline.

The dehydration of tetracycline at the C-5a-C-6 position as a function of acidity was investigated at various temperatures. The rate was first order with respect to tetracycline and with respect to [H+]. Rate constants and an activation energy are reported. Tetracycline was unstable in dilute acid.

Anhydrides↗
PubMed1975

Ventricular premature beats and mortality of men with coronary heart disease.

Frequency and qualitative characteristics of ventricular premature beats (VPB) are determined from 1 hour of electrocardiogram (ECG) monitoring of men with coronary heart disease in a continuing study among members of the Health Insurance Plan of Greater New York. Mortality among 924 such men during an average observation period of 10 months was higher among men with VPB than among those free of VPB. In comparison with the routine 12-lead ECG, the hour of ECG monitoring increased the proportion of men identified as showing ectopic activity from 15% to 52%. Only half of men with 10 or more VPB in the hour of monitoring were noted as having VPB on the routine ECG; mortality among these men was relatively high whether or not VPB appeared on the short sample ECG.

Adult↗
PubMed1974

Effects of DC electric countershock on ventricular function, cation balance and endogenous norepinephrine in the dog heart.

Effects of DC electric countershock on cardiac function in thoracotomized dogs were evaluated from recordings of ECG, aortic pressure, left ventircular pressure and its first derivative, and coronary sinus flow. Samples of arterial and coronary venous plasma and left ventricular myocardium obtained before and after countershock at times corresponding to post-shock arrhythmias and recovery were analyzed for Mg++, K+ and Ca++, and norepinephrine. At 1 min after countershock, ECG changes included transient cardiac arrhythmias and ST segment alterations, accompanied by depressed ventricular function and decreased myocardial Ca++ concentration. At 5 min postshock, coronary venous Mg++ and K+ concentrations had risen and ventricular function was still depressed. Function recovered within 10-20 min. There was no evidence of consistent loss of endogenous myocardial norepinephrine.

Animals↗