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Biomedical subjects

J Kozlowski

Publications and source records attributed to J Kozlowski.

At least 19 recordsLinked to original sources
PubMed1988

Risks associated with intraaortic balloon pumping in patients with and without diabetes mellitus.

Between 1967 and 1982, intraaortic balloon pumping (IABP) was attempted in 733 patients. Of these, 132 were diabetic: 51 patients were managed with diet alone, 46 patients took oral hypoglycemic agents and 35 patients required insulin. Vascular complications associated with IABP occurred in 34% of the insulin-dependent diabetics, in 18% of other diabetics and in 14% of nondiabetic patients. Infectious complications were 37, 22 and 25%, respectively. Seventy-five diabetic patients (57%) were discharged alive from the hospital after balloon pumping, essentially the same proportion as among nondiabetic patients (58%). It is concluded that although diabetics incur a higher complication rate, IABP is not contraindicated.

Adult↗
PubMed1986

Studies of Doppler aortic flow velocity during supine bicycle exercise.

Although Doppler echocardiography is useful in the assessment of left ventricular function at rest, little information is available on the application of this technique during exercise. Consequently, Doppler aortic flow studies were performed in 17 young normal subjects during and after supine bicycle exercise. The purposes of the study were to determine the feasibility of recording Doppler aortic flow velocity with a suprasternal notch transducer during exercise and to assess the changes in normal aortic flow velocity parameters during exercise and early recovery. Each subject exercised until fatigue; mean duration of exercise was 10 minutes. Heart rate increased from a mean of 69 beats/min at control to 159 beats/min at peak exercise. On average, aortic peak flow velocity increased by 45% from control, reaching its maximum at 2 minutes after exercise. Ejection time decreased by 34% during exercise, being shortest at peak exercise. Heart rate, peak flow velocity and ejection time had not returned to normal by 10 minutes after exercise. Aortic flow velocity integral (a relative measure of stroke volume) decreased by 10% at peak exercise (p less than 0.05) compared with control, but had returned to control at 2 minutes after exercise. Despite mild aliasing, increased spectral dispersion, faster heart rates and increased respiratory rate during maximal exercise, aortic flow velocity measurements could be recorded using the suprasternal technique. These baseline Doppler exercise data should be useful in further studies of exercise hemodynamic changes in patients with heart disease.

Adolescent↗
PubMed1986

The scintigraphic evaluation of myocardial infarction and regional ventricular performance using technetium-99m hexakis (t-butylisonitrile) technetium (I) (TBI): a new myocardial imaging agent.

Technetium-99m hexakis (t-butylisonitrile) technetium (I) (99mTc-TBI) is a new myocardial perfusion imaging agent. To determine its potential in the evaluation of myocardial infarction, 15 patients with suspected or confirmed acute infarction were studied by bedside imaging in the coronary care unit. Good-quality planar scintigrams in multiple projections were obtained in 13 patients. Gated perfusion studies were performed in 14 patients, and for comparison 13 of these were restudied 24-72 h later by standard gated equilibrium blood pool radionuclide ventriculography. Conventional and planar scintigraphic criteria for myocardial infarction (acute or old) agreed in 12 (92%) patients (k = 0.81, p less than 0.05). All the infarctions detected by scintigraphy were associated with electrocardiographic Q-waves. Localization of infarction by the electrocardiogram and scintigraphy exhibited moderate agreement (k = 0.49, p less than 0.1). Regional wall motion analysis by standard radionuclide ventriculography and gated 99mTc-TBI scintigraphy were in complete agreement for 25 (64%) of 39 left ventricular segments (k = 0.35, p less than 0.05). However, in 7 other segments, associated with areas of infarction, regional wall motion abnormalities were noted only on gated 99mTc-TBI scintigraphy. Therefore, 99mTc-TBI scintigraphy can readily provide data on regional myocardial perfusion and wall motion, permitting detection and localization of areas of myocardial infarction. The superior imaging properties, ready availability and low cost of 99mTc point to the considerable potential value of 99mTc-TBI in assessing patients with suspected or confirmed myocardial infarction.

Adult↗
PubMed1983

Cardiac rupture following intracoronary streptokinase.

Thrombolytic dissolution of coronary artery thrombus has added new dimensions to early myocardial infarction treatment. Reperfusion via streptokinase infusion has been shown to be beneficial; however, adverse effects are being noted. We present the case of a patient so treated who subsequently developed left ventricular free wall rupture.

Coronary Disease↗
PubMed1983

Prevention by nifedipine of cold pressor-induced decrease in left ventricular ejection fraction.

To examine the effects of nifedipine on changes in ventricular function produced by cold, the cold pressor test was administered to eight patients with angiographically documented coronary artery disease. Radionuclide ventriculograms were obtained at baseline and during the cold pressor stimulus both before and after administration of nifedipine, 10 mg buccally; thus, four serial radionuclide ventriculograms were obtained per patient. The cold pressor stimulus did not produce any significant difference in the mean (+/- standard deviation) peak rate-pressure product during the control or nifedipine test (10,900 +/- 3,390 versus 10,600 +/- 3,700). However, the increase in systolic blood pressure (p = 0.05) and the peak systolic blood pressure achieved (p less than 0.001) were greater during the control (134 +/- 19 to 160 +/- 25 mm Hg) than during the nifedipine (125 +/- 18 to 145 +/- 21 mm Hg) cold pressor test. The mean global left ventricular ejection fraction decreased during the control cold pressor test from a baseline value of 0.60 +/- 0.08 to 0.52 +/- 0.08 (p = 0.004). After nifedipine, this variable did not change during the repeat cold pressor test (0.63 +/- 0.09) compared with the repeat baseline value (0.63 +/- 0.11). Therefore, the difference in left ventricular ejection fraction response during control versus nifedipine cold pressor testing was highly significant (p less than 0.0001). In patients with obstructive coronary artery disease, nifedipine abolished the decrease in left ventricular ejection fraction observed during the control cold pressor test and may be of value to protect patients from cold-induced left ventricular dysfunction. The mechanism may be a combination of coronary artery vasodilation and systolic unloading of the left ventricle.

Adult↗
PubMed1982

Synthesis, 470-MHz 1H NMR spectra, and activity of delactonized derivatives of the anticancer drug etoposide.

The anticancer drug etoposide (VP 16-213, 1) contains a highly strained trans-fused gamma-lactone. This functionality is readily metabolized to an inactive ring-opened hydroxy acid (2). To prevent this detoxification of the drug and to investigate whether the lactone is essential for drug activity, we synthesized a cyclic ether analogue of etoposide (3) and tested it in the mouse leukemia L1210 system in vitro and in vivo. This ether analogue of etoposide was found to retain activity in the L1210 system, but the activity was reduced relative to the parent drug. A synthetic intermediate, the ring D opened diol of the reduced lactone (4), was also tested and found to be inactive in the L1210 system. The complete 470-MHz 1H NMR spectra of etoposide and its derivatives are reported. The usefulness of introducing deuterium at C-13 to determine J2,3 is also demonstrated. This coupling constant is characteristic of cis or trans stereochemistry across the C-D ring fusion.

Animals↗
PubMed1982

Effect of exercise on erythrocyte count and blood activity concentration after technetium-99m in vivo red blood cell labeling.

We studied the effect of exercise on blood radiotracer concentration after technetium-99m in vivo red blood cell labeling. After red blood cell labeling, 13 subjects underwent maximal supine bicycle exercise. Radioactivity, analyzed with a well counter, was measured in heparinized venous blood samples drawn at rest and during peak exercise. Changes in activity were compared with changes in erythrocyte count. Activity and erythrocyte counts increased during exercise in all 13 subjects. Percent increase in activity correlated with percent increase in erythrocyte count (r = -0.78), but did not correlate with either duration of exercise or maximal heart rate. Twenty minutes after termination of exercise, activity and erythrocyte count had decreased from peak exercise values but remained higher than preexercise values. In nine nonexercised control subjects, samples drawn 20 minutes apart showed no change in activity or in erythrocyte count. We conclude that exercise increases blood activity, primarily because of an increase in erythrocyte count. During radionuclide ventriculography, blood activity must be measured before and after any intervention, particularly exercise, before a change in left ventricular activity can be attributed to a change in left ventricular volume.

Adult↗
PubMed1981

Use of equilibrium (gated) radionuclide ventriculography to quantitate left ventricular output in patients with and without left-sided valvular regurgitation.

We examined the accuracy with which left ventricular output can be estimated by equilibrium radionuclide ventriculography. After red blood cells were labeled in vivo, we measured left ventricular end-diastolic and end-systolic count rates and the count rate in 5 ml of the patient's blood. After estimating the average ratio of counting efficiency for the left ventricle to counting efficiency for the blood sample (Elv/Es) in six patients, we calculated left ventricular output in 26 other patients as (left ventricular activity ejected per minute divided by activity per liter of blood) divided by the previously estimated Elv/Es. Radionuclide left ventricular output closely approximated Fick cardiac output (r = 0.94) in patients without mitral or aortic regurgitation and exceeded Fick cardiac output in all patients with valvular regurgitation. Regurgitant fraction, calculated as the difference between the radionuclide and Fick outputs divided by the radionuclide output, correlated with the severity of of regurgitation as assessed angiographically. The equilibrium radionuclide ventriculogram is an excellent means for noninvasive estimation of left ventricular output.

Adult↗