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Biomedical subjects

M G Levine

Publications and source records attributed to M G Levine.

At least 19 recordsLinked to original sources
PubMed2000

Comparison of electrocardiographic-gated technetium-99m sestamibi single-photon emission computed tomographic imaging and rest-redistribution thallium-201 in the prediction of myocardial viability.

Although the combined assessment of perfusion and function using rest electrocardiographic (ECG)-gated technetium-99m (Tc-99m) sestamibi single-photon emission computed tomographic (SPECT) imaging has been shown to improve sensitivity and accuracy over perfusion alone in the prediction of myocardial viability, no data are available comparing this technique with rest-redistribution thallium-201. Thirty patients with coronary artery disease and left ventricular dysfunction (ejection fraction < or = 40%) underwent rest-redistribution thallium-201 and rest ECG-gated Tc-99m sestamibi SPECT imaging before revascularization and rest ECG-gated Tc-99m sestamibi SPECT imaging at 1 or 6 weeks after revascularization. All thallium-201 and Tc-99m sestamibi images were interpreted by a consensus agreement of 3 experienced readers without knowledge of patient identity or time of imaging with Tc-99m sestamibi (before or after revascularization) using a 17-segment model. Concordance between techniques for the prediction of viability was 89% (kappa 0.556 +/- 0.109). With rest-redistribution thallium-201, sensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy were 95%, 59%, 88%, 78%, and 86%, respectively. With rest ECG-gated Tc-99m sestamibi SPECT imaging, sensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy were 96%, 55%, 87%, 80%, and 86%, respectively (p = NS vs rest-redistribution thallium-201). Although both techniques are comparable for detecting viable myocardium, rest ECG-gated Tc-99m sestamibi SPECT imaging allows direct assessment of both myocardial perfusion and ventricular function, which may be clinically useful in patients who require assessment of myocardial viability.

Coronary Disease↗
PubMed1999

Functional assessment with electrocardiographic gated single-photon emission computed tomography improves the ability of technetium-99m sestamibi myocardial perfusion imaging to predict myocardial viability in patients undergoing revascularization.

This study evaluates the use of electrocardiographic (ECG) gated single-photon emission computed tomographic (SPECT) myocardial perfusion imaging for the prediction of viability in patients undergoing revascularization, who have coronary disease and left ventricular dysfunction. Fifty patients underwent technectium-99m (Tc-99m) sestamibi ECG gated SPECT imaging preoperatively at rest and 1 week after revascularization, whereas 36 (72%) also underwent imaging 6 weeks after revascularization. Images were interpreted by the consensus of 3 experienced readers without knowledge of patient identity or time of imaging (pre- or postrevascularization) for perfusion and wall motion using a 17-segment model. Results of perfusion alone were compared with perfusion and wall motion combined. One hundred five coronary artery territories were revascularized, 96 of which were viable and 9 nonviable. Perfusion alone predicted 87 to be viable and 18 nonviable (sensitivity 86%, specificity 55%, positive predictive value 95%, negative predictive value 28%, and overall accuracy 85%). Perfusion and wall motion combined identified 95 territories to be viable (sensitivity 95%; p <0.025; specificity 55%, positive predictive value 96%, negative predictive value 50%, and overall accuracy 91%; p <0.05). Thus, Tc-99m sestamibi ECG gated SPECT myocardial perfusion imaging at rest allows assessment of both perfusion and wall motion, which significantly improves the sensitivity and overall accuracy for determination of viability in comparison with perfusion alone.

Aged↗
PubMed1999

Implementing and integrating computer-based activities into a problem-based gross anatomy curriculum.

A problem-based learning curriculum in gross anatomy was begun for a limited number of students to address unsuccessful methodology inherent in a traditional instructional approach. To eliminate some concerns associated with the laboratory component, computer-based instruction and other computer- related activities were actively integrated into the total instructional process. Prosections, directions, quizzes, images, and grades were provided in lab at table-side computer workstations, in the library, and on the web. Results were assessed through questionnaires in which students rated their learning experience according to a Likert-type scale. Success was measured by quantitative improvements in student perception. In this three-year study, observations and measurements have suggested increasingly positive student attitudes toward educational technology, for networks as a faster and more effective method of student/faculty communication, and in the utilization of computer-based instruction for greater flexibility and efficiency in learning. This allowed a rethinking of the structure and content of the curriculum by the faculty, which permitted reduced laboratory time, more small-group activity, and less reliance on staff.

Anatomy↗
PubMed1998

Combined assessment of myocardial perfusion and left ventricular function with exercise technetium-99m sestamibi gated single-photon emission computed tomography can differentiate between ischemic and nonischemic dilated cardiomyopathy.

The purpose of this study was to determine whether exercise technetium-99m sestamibi gated single-photon emission computed tomography (SPECT) accurately distinguishes between patients with ischemic cardiomyopathy and patients with nonischemic left ventricular systolic dysfunction. Noninvasive tests have previously failed to accurately separate patients with ischemic cardiomyopathy from those with nonischemic cardiomyopathy. Technetium-99m gated SPECT imaging offers advantages that have the potential to overcome the limitations of previous studies. Thirty-seven adults with a left ventricular ejection fraction < or = 35%, including 24 patients with nonischemic cardiomyopathy and 13 patients with ischemic cardiomyopathy, were prospectively evaluated using symptom-limited metabolic exercise treadmill testing with technetium-99m sestamibi gated SPECT imaging. Interpretation of myocardial perfusion and regional wall motion was performed, using a 17-segment model. Summed stress, rest, and reversibility perfusion defect scores were determined, and the variance of segmental wall motion scores was computed. Summed stress, rest, and reversibility perfusion defect scores were significantly lower in nonischemic cardiomyopathy patients, compared with those with ischemic cardiomyopathy (summed stress defect score: 6.9 +/- 3.8 vs 32.9 +/- 7.7, respectively, p <0.001). Variability in segmental wall motion was also significantly lower in patients with nonischemic cardiomyopathy compared with those with ischemic cardiomyopathy (variance: 0.3 +/- 0.3 vs 1.2 +/- 0.8, respectively, p <0.001). Thus, assessment of myocardial perfusion and regional ventricular function with exercise technetium-99m sestamibi gated SPECT imaging can reliably distinguish between patients with ischemic cardiomyopathy and patients with nonischemic dilated cardiomyopathy.

Adult↗
PubMed1998

Dipyridamole-dobutamine stress with Tc-99m sestamibi tomographic myocardial perfusion imaging.

In 66 patients unable to exercise referred for pharmacologic stress single-photon emission computed tomographic myocardial perfusion imaging, a moderate dose of dobutamine was combined with intravenous dipyridamole and the results were compared with standard intravenous dipyridamole stress. The combined stress protocol resulted in increased defect size and reversibility with technetium-99m sestamibi single-photon emission computed tomographic myocardial perfusion imaging.

Aged↗
PubMed1998

An overview of the medical informatics curriculum in medical schools.

As medical schools incorporate medical informatics into their curriculum the problems of implementation arise. Because there are no standards regarding a medical informatics curriculum, medical schools are implementing the subjects in various ways. A survey was undertaken to amass an overview of the medical informatics curriculum nationally. Of the responding schools, most have aspects of medical informatics incorporated into current courses and utilize existing faculty. Literature searching, clinical decision-making, and Internet are the basic topics in the current curricula. The trend is for medical informatics to be incorporated throughout all four years of medical school. Barriers are the difficulties in faculty training, and slow implementation.

Curriculum↗
PubMed1993

Definition of inseparably fused ventricular myocardium in thoracopagus: fetal echocardiographic utility and pathologic refinement.

Correlative echocardiographic and pathological findings in a thoracopagus with conjoined hearts are reported. One twin had tricuspid atresia with discordant atrioventricular connections and concordant ventriculoarterial connections. The morphologic right ventricle was hypoplastic and there was a large muscular ventricular septal defect. The other twin had hypoplasia of the mitral valve anulus and left ventricle with double-outlet right ventricle and pulmonary valve atresia. The tricuspid valve was severely insufficient in part because of a large orifice and redundant, elongated leaflets with abnormal chordal attachments. The left ventricles of these two twins shared a perforated common "free wall" with at least two large defects allowing mixing of the circulations at that level. Not all anatomic details were established conclusively by fetal echocardiography; however, sufficient diagnostic information was obtained to support a decision not to aggressively resuscitate these twins after elective cesarean delivery at 31 weeks' gestation.

Adult↗
PubMed1990

Perinatal outcomes of twin pregnancies at term.

A review of a two-year experience in our community disclosed that 57% of twin pregnancies (118/207) deliver at term. Little attention has been focused on perinatal outcomes of twin pregnancies remaining undelivered after 36 completed weeks. Therefore, we reviewed our experience to determine whether our practice should change to maximize perinatal care. Nearly all the study pregnancies (115/117, or 97.5%) delivered by the estimated date of confinement. Fetal malpresentation, failure to progress and the patient's lack of desire for a vaginal birth after cesarean delivery were common reasons for the high cesarean rate (62/117, or 52%). The neonatal outcomes were favorable regardless of the route or interval between deliveries. Discordant fetal growth was found in only eight cases (6.8%). No perinatal deaths occurred, and five-minute Apgar scores less than 7 (2/234, or 0.9%) and rates of anomalies (5/234, or 2.1%) were not different from those in singleton pregnancies delivering during the same period. Using the principles of obstetric practice used in our community, we would expect the perinatal outcomes in term twin gestations to be favorable.

Cesarean Section↗
PubMed1988

Total parenteral nutrition for the treatment of severe hyperemesis gravidarum: maternal nutritional effects and fetal outcome.

Hyperemesis gravidarum is a complication of pregnancy that can lead to severe maternal nutritional deprivation. Total parenteral nutrition has been used in pregnancy complicated by hyperemesis gravidarum. However, little has been done to study the nutritional aspects of hyperemesis or the maternal effects of total parenteral nutrition when given during the first trimester of pregnancy. The purpose of this study was to examine the nutritional state of pregnancy complicated by hyperemesis gravidarum and the effects of total parenteral nutrition on maternal nutrition and fetal outcome when given during the first trimester of pregnancy. Using a standard method of indirect calorimetry, the basal metabolic expenditure and adjusted metabolic expenditure were determined, and appropriate calories were calculated for each patient. The patients were then started on total parenteral nutrition. Follow-up indirect calorimetry studies showed improved nutritional status, with return of anabolic parameters. The results of this study support the conclusion that total parenteral nutrition given during the first trimester is a safe and effective method of nutritional support.

Birth Weight↗
PubMed1984

Uterine vascular effects of estetrol in nonpregnant ewes.

Estetrol is produced by the fetal liver and has been suggested to be a sensitive indicator of fetal well-being. Although the uterine vascular effects of estrogens (17 beta-estradiol, estriol, and estrone) have been extensively investigated in our laboratory and those of others, the ability of estetrol to dilate the ovine uterine vasculature is not presently known. The present experiment was designed to compare the vasoactivity of estetrol to that of a second pregnancy-associated estrogen, estriol. Five nonpregnant oophorectomized ewes were chronically instrumented with catheters in the femoral artery, femoral vein, uterine arteries, and electromagnetic flow probes on both uterine arteries. Upon recovering from operation, animals received unilateral intra-arterial (uterine) injections of either estriol (0.1, 0.3, 1, and 3 micrograms) or estetrol (1, 3, 10, and 30 micrograms). Ewes received only one dose of either estetrol or estriol daily and all doses were given in a randomized order. Uterine blood flow responses were continuously monitored and the time of onset, peak, and duration were recorded. The time of onset (38 +/- 2 minutes), time of peak response (75 +/- 1 minute), and duration (189 +/- 7 minutes) were approximately equal to those observed for estriol. On the basis of the data obtained in the present study we have determined that estetrol is 15 to 30 times less potent than estriol as a uterine vasodilator.

Animals↗
PubMed1984

Birth trauma: incidence and predisposing factors.

The authors retrospectively studied 13,870 singleton full-term consecutive live births at a major teaching hospital and assessed the frequency of brachial plexus injury, clavicular fracture, and facial nerve injury in newborns delivered from January 1974 through December 1977 and from January 1979 through September 1981. Predisposing factors relating to mechanical birth trauma were defined, and a risk assessment profile was developed to identify the fetus at risk. Mechanical injuries were identified according to the International Classification of Diseases codes 761. The incidence of selected birth injuries in the study group were: brachial plexus injury, 2.6 per 1000 or 1 in 385 single full-term live births; fractured clavicle, 2.0 per 1000 or 1 in 495 single full-term live births; and facial nerve injury, 7.5 per 1000 or 1 in 133 single full-term live births. There were 162 full-term infants born with 168 injuries relevant to this study. Of the six infants who incurred more than one injury, three had a combined fractured clavicle-brachial plexus injury, and three had facial nerve-branchial plexus injuries. Logistic regression analysis of fetal, maternal, and intrapartum complications in labor and delivery revealed that midforceps , shoulder dystocia, low forceps, infants greater than 3500 g, and second stage labor exceeding 60 minutes were the predominant events associated with fetal injury. The authors then applied a risk assessment profile to successfully identify over 50% of the injured and 84% of the uninjured groups. From their results, the authors suggest that obstetricians should alert the pediatricians when these predisposing factors exist to aid in the recognition and early treatment of these birth injuries.

Birth Injuries↗
PubMed1983

The U.S. M-16 rifle versus the Russian AK-47 rifle. A comparison of terminal ballistics.

The standard U.S. military rifle (M-16) is substantially more destructive than its Russian counterpart (AK-47) when fired at short range into clay blocks, despite the fact that the AK-47 is of larger caliber and fires a much heavier bullet with a kinetic energy (muzzle) 25% greater when compared to the M-16. The decisive factor is the 40% greater muzzle velocity of the M-16.

Forensic Medicine↗