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Biomedical subjects

M Cohen

Publications and source records attributed to M Cohen.

At least 559 records · Page 31Linked to original sources
PubMed1991

Usefulness of ST-segment changes in greater than or equal to 2 leads on the emergency room electrocardiogram in either unstable angina pectoris or non-Q-wave myocardial infarction in predicting outcome.

To determine the reliability of the admission electrocardiogram in predicting outcome in patients hospitalized for chest pain at rest, 90 patients were randomized into a trial of aspirin versus heparin in unstable angina or non-Q-wave myocardial infarction, and prospectively followed for 3 months. The emergency room admission electrocardiogram was analyzed for ST-segment deviation greater than or equal to 1 mm/lead and T-wave changes. Unfavorable outcomes were recurrent ischemic pain, myocardial infarction and coronary revascularization with angioplasty or surgery. In patients who underwent coronary arteriography, a myocardium in jeopardy score ranging from 0 to 10 was assigned, based on the number of vessels with a diameter stenosis greater than or equal to 70% and the location of the stenoses. Considering all 90 patients, an admission electrocardiogram with ST-segment deviation in greater than or equal to 2 leads had a positive predictive value for adverse clinical events of 79% and a negative predictive value of 64%. In the subset of patients without left ventricular hypertrophy and whose admission electrocardiograms were recorded during chest pain (62 of 90), the positive predictive value of ST deviation in greater than or equal to 2 leads improved to 89% and the negative value to 72%. Of the 62 patients, 53 underwent coronary arteriography. There was a positive linear correlation between the total number of leads with ST-segment deviation and the myocardium in jeopardy score (r = 0.80, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Clinical research.

Explore the source record for details and available documents.

Community Medicine↗
PubMed1991

French intravenous drug users: knowledge and sexual behavior change.

In a population based survey conducted in France in 1988, 41 respondents reported present or past intravenous drug use. Controlling for age and gender, intravenous drug users (IDUs) engage in more high risk sexual behavior than the general population (sex with other IDUs, multiple partners), but they do not use condoms more frequently. They are five times more likely to have had an HIV test.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Percutaneous coronary excimer laser-assisted balloon angioplasty: initial clinical and quantitative angiographic results in 50 patients.

The initial clinical experience and quantitative angiographic results of percutaneous coronary excimer laser-assisted balloon angioplasty are described for 55 lesions in 50 patients. With use of a xenon chloride (308 nm) excimer laser generator and 1.5 to 1.75 mm catheters, excimer laser angioplasty was attempted at 135 ns pulse width, 25 to 40 Hz repetition rate, 2 to 5 s laser delivery time and 30 to 60 mJ/mm2 energy fluence. Laser success (greater than 20% reduction in absolute percent diameter stenosis) was achieved in 41 (75%) of 55 lesions, with 100% subsequent balloon angioplasty success (less than 50% residual stenosis). By quantitative digital caliper technique, the percent diameter stenosis (mean +/- SE) was reduced from 81 +/- 1% to 50 +/- 3% after excimer laser angioplasty (p less than 0.001) and to 20 +/- 1% after balloon angioplasty (p less than 0.001); minimal luminal diameter increased from 0.56 +/- 0.04 to 1.46 +/- 0.08 mm (p less than 0.001) and 2.03 +/- 0.07 mm (p less than 0.001), respectively. By videodensitometric techniques, the percent area stenosis decreased from 86 +/- 2% to 54 +/- 3% after excimer angioplasty (p less than 0.001) and to 26 +/- 3% after balloon angioplasty (p less than 0.001). There were no perforations, need for emergency bypass surgery or deaths. The overall incidence of abrupt closure (3.6%), dissection (1.8%), embolization (1.8%), filling defect (6%), myocardial infarction (5.5%), side branch occlusion (3.6%) or spasm (3.6%) was infrequent and more related to subsequent balloon angioplasty than to the laser procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Laser↗
PubMed1991

Sustained ventricular tachycardia associated with sarcoidosis: assessment of the underlying cardiac anatomy and the prospective utility of programmed ventricular stimulation, drug therapy and an implantable antitachycardia device.

The presentation, cardiac anatomy and utility of programmed ventricular stimulation in seven patients with sustained ventricular tachycardia associated with sarcoidosis are described. The mean patient age was 38 +/- 8 years. Pulmonary involvement was apparent in three patients and no systemic manifestations of sarcoidosis were present in one patient. All patients had electrocardiographic abnormalities at rest and six had a left ventricular ejection fraction less than 45%. All seven patients had left ventricular wall motion abnormalities and five had mitral valve dysfunction. Sustained ventricular tachycardia was easily induced in all patients. Spontaneous sustained ventricular tachycardia was not prevented with corticosteroid administration. Despite antiarrhythmic drug therapy, two patients had sudden cardiac death and an additional four had recurrence of ventricular tachycardia. Four patients had an automatic cardioverter-defibrillator implanted and received drug therapy; all four received appropriate shocks. This report represents the largest descriptive series of consecutive patients with sustained ventricular tachycardia associated with sarcoidosis. Antiarrhythmic drug therapy of ventricular tachycardia in patients with sarcoidosis, even when guided with programmed ventricular stimulation, is associated with a high rate of arrhythmia recurrence or sudden death, or both. Thus, implantation of an automatic antitachycardia device (cardioverter-defibrillator) should be considered as primary therapy in such patients. Furthermore, sarcoidosis should be excluded, with Kveim skin testing if necessary, in any patient with sustained ventricular tachycardia of unknown origin.

Adult↗
PubMed1991

Significance of seizures associated with extracorporeal membrane oxygenation.

We previously reported a predominance of left focal motor seizures in infants receiving extracorporeal membrane oxygenation (ECMO), raising concerns about possible ischemia resulting from the right common carotid artery ligation. We therefore evaluated the neurologic and psychologic outcome at 2 years of age of all infants with ECMO-related seizures. Although 8 of 12 infants had left focal seizures in infancy, there was no lateralization of motor findings at 2 years of age; left hemiparesis was present in three of the infants and right hemiparesis in three. The developmental quotient was normal in 6 of 12 infants, low-average in three, borderline in two, and in the mentally handicapped range in one. We conclude that any ischemia resulting from carotid ligation is not great enough to produce long-term lateralizing findings but that seizures during ECMO are a risk factor for later cerebral palsy or developmental delay.

Child Behavior↗
PubMed1991

Effects of enflurane and isoflurane on hepatic and renal circulations in chronically instrumented dogs.

Seven dogs were chronically instrumented for measurements of mean aortic blood pressure and cardiac output and for simultaneous measurements of hepatic, portal, and renal blood flows. Each animal was studied on two separate occasions, awake and during 1.2, 1.4, 1.75, and 2.0 MAC isoflurane and enflurane. Both anesthetics induced tachycardia; to a greater degree than isoflurane, enflurane lowered mean aortic blood pressure in a dose-dependent manner (-37, -45, -48, and -62% vs. -19, -25, -41, and -44%, respectively) and cardiac output (-20, -26, -41, and -48% vs. -3, -5, -11, and -15%, respectively). With isoflurane, cardiac output decreased only at 1.75 and 2.0 MAC, and portal blood flow did not change significantly, whereas hepatic arterial blood flow increased at 1.75 and 2 MAC (by 28 and 33%, respectively). With enflurane, no significant changes were recorded in hepatic arterial blood flow, whereas portal blood flow decreased in a dose-dependent manner. Except at 2 MAC, hepatic circulation did not differ between anesthetics. Likewise, neither anesthetic significantly changed renal blood flow, except for enflurane at 2.0 MAC, which was associated with a 35% reduction. Both anesthetics led to similar systemic, hepatic, and renal vasodilations. Our data suggest that high concentrations of enflurane are associated with decreases in portal, total hepatic, and renal blood flows, most likely as a result of an anesthetic-induced cardiac depression.

Animals↗
PubMed1991

Comparison of the effects of isoflurane and desflurane on cardiovascular dynamics and regional blood flow in the chronically instrumented dog.

Seven mongrel dogs were chronically instrumented for the measurement of aortic and left ventricular blood pressures, cardiac output, left ventricular wall thickening, left ventricular dP/dt, and circumflex coronary, renal, hepatic and portal blood flows under the influence of desflurane (D) and isoflurane (I). Administration of the two anesthetics, was randomized, as was the order of the concentrations administered. Each dog was studied awake and at 1.2, 1.4, 1.75, and 2.0 MAC of each anesthetic on different days. Both anesthetics decreased mean arterial pressure, stroke volume, systemic vascular resistance, left ventricular dP/dt, and wall thickness. The decreases were dose-dependent for mean arterial pressure (percent of awake values: D 78, I 85 at 1.2 MAC, and D 67, I 69 at 2.0 MAC); stroke volume (D 66, I 72 at 1.2 MAC, and D 52, I 57 at 2.0 MAC); dP/dt (D 61, I 64 at 1.2 MAC, and D 46, I 49 at 2.0 MAC); and WT (D 68, I 70 at 1.2 MAC, and D 47, I 60 at 2.0 MAC). Systemic vascular resistance decreased approximately the same at 1.2 MAC (D 71, I 87%) as at 2.0 MAC (D 71, I 79%). Heart rate increased but also not in a dose-dependent fashion (percent of awake values: D 177, I 145 at 1.2 MAC, and D 176, I 155 at 2.0 MAC). Coronary blood flow was increased by both anesthetics at all concentrations (percent of awake values: I 136 at 1.2 MAC and 161 at 2.0 MAC of awake, and D 131 at 1.2 MAC and 138 at 2.0 MAC.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Long-term effects of rigid fixation on the growing craniomaxillofacial skeleton.

Fixation of craniomaxillofacial bones with plates and screws is becoming an increasingly popular method of managing patients with maxillofacial fractures, congenital anomalies, and skeletal defects after tumor extirpation. The effects of rigid fixation on growth, however, are not well defined and remain controversial. This experimental work was designed to evaluate the effects of rigid fixation on the growing craniomaxillofacial skeleton. Eight 2-month-old beagle dogs were divided into two groups. Cephalometric analysis and computed tomography were obtained preoperatively to establish a baseline of the craniomaxillofacial skeleton. Rigid fixation using plates and screws was applied across the intact coronal and nasofrontal sutures. The contralateral side served as the control. The periosteum was elevated over the contralateral suture and replaced without any surgical intervention. The animals were killed one year after application of rigid fixation, when they had achieved full and mature skeletal growth. The skulls were evaluated both grossly and cephalometrically. There was bony growth over some of the plates, as well as sclerosis of the plated suture lines. Cephalometric analysis demonstrated consistent asymmetry between the plated and nonplated sides, with deviation of the midline toward the plated side in all of the animals. Although further studies are necessary to clarify this issue fully, we conclude from our study that rigid fixation during skeletal development can potentially alter the growth patterns of the craniomaxillofacial skeleton and should be used with caution.

Animals↗
PubMed1991

Chronic wounds and delusions of parasitosis in the drug abuser.

Plastic surgeons are routinely consulted about the care of difficult or chronic wounds. Most of these wounds have a physiologic basis and are treated according to basic wound-healing principles. Patients with factitious wounds are difficult to treat and present diagnostic dilemmas. We present a case and review of the literature of drug-induced delusions of parasitosis to inform plastic surgeons of this important entity and for consideration in the differential diagnosis of chronic wounds.

Adult↗
PubMed1991

Electrocardiographic body surface potential mapping in the Wolff-Parkinson-White syndrome. Noninvasive determination of the ventricular insertion sites of accessory atrioventricular connections.

BACKGROUND: A reliable, noninvasive procedure to determine the location of accessory atrioventricular connections in patients with Wolff-Parkinson-White syndrome would add an important diagnostic tool to the clinical armamentarium. METHODS AND RESULTS: Body surface potential mapping (BSPM) using 180 electrodes in various-sized vests and displayed as a calibrated color map was used to determine the ventricular insertion site of the accessory atrioventricular (AV) connections in 34 patients with Wolff-Parkinson-White syndrome. Attempts were made to determine the 17 ventricular insertion sites described by Guiraudon et al. All 34 patients had an electrophysiologic study (EPS) at cardiac catheterization, and 18 had surgery so the ventricular insertion sites could be accurately located using EPS at surgery. A number of physiologic observations were also made with BSPM. CONCLUSIONS: The following conclusions were drawn: 1) BSPM using QRS analysis accurately predicts the ventricular insertion site of accessory AV connections in the presence of a delta wave in the electrocardiogram; 2) the ventricular insertion sites of accessory AV connections determined by BSPM and by EPS at surgery were identical or within one mapping site (1.5 cm or less) in all but four of 18 cases; three of the four exceptions had more than one accessory AV connection, and the other had a very broad ventricular insertion; 3) BSPM and EPS locations of the accessory AV connections correlated very well in the 34 cases despite the fact that BSPM determines the ventricular insertion site and EPS determines the atrial insertion site of the accessory AV connection; 4) as suggested by the three cases of multiple accessory AV connections, EPS and BSPM may be complementary since BSPM identified one pathway and EPS identified the other (in the case with a broad ventricular insertion, BSPM and EPS demonstrated different proportions of that insertion); 5) BSPM using ST-T analysis is very much less accurate in predicting the ventricular insertion site of accessory AV connections unless there is marked preexcitation; 6) standard electrocardiography using the Gallagher grid methodology (but with no attempt at stimulating maximal preexcitation) was not as accurate as QRS analysis of BSPM in predicting the ventricular insertion site of the accessory AV connection; however, exact comparison is hampered by the different number and size of the Gallagher and Guiraudon insertion sites; 7) BSPM using QRS analysis appears to be very accurate in predicting right ventricular versus left ventricular posteroseptal accessory AV connections; 8) typical epicardial right ventricular breakthrough, indicative of conduction via the specialized AV conduction system, occurs in all patients with left ventricular free wall accessory AV connections; 9) epicardial right ventricular breakthrough was not observed in cases with right ventricular free wall or anteroseptal accessory AV connections; 10) epicardial right ventricular breakthrough can occur in the presence of posteroseptal accessory AV connections, whether right or left ventricular; and 11) the delay in epicardial right ventricular breakthrough in cases with left ventricular insertion may provide a marker to estimate the degree of ventricular preexcitation.

Adult↗
PubMed1991

Effects of atracurium and pancuronium on the oculocardiac reflex in children.

The authors compare the effect of two muscle relaxants, atracurium and pancuronium, on the bradycardia resulting from the oculocardiac reflex during eye surgery for strabismus in children. Two groups, each composed of 15 children, received either pancuronium or atracurium during strabismus operations. Heart rate and rhythm were observed at several points during the operations, and the changes that occurred in the two groups were compared. We found that the incidence and severity of the bradycardia, the incidence of dysrhythmias, and the need for atropine administration were significantly greater in the atracurium group than in the pancuronium group.

Atracurium↗
PubMed1991

Vessel wall-related risk factors in acute vascular events.

Angiography in patients with unstable angina or myocardial infarction with subtotal coronary occlusion often reveals eccentric stenoses with irregular borders, suggesting ruptured atherosclerotic plaques and thrombosis, as documented by angioscopy and at autopsy. We have studied these processes in an ex vivo perfusion chamber, an in vivo swine model, and in human subjects. Our results, and those of other investigators, suggest that specific local risk factors at the time of plaque disruption influence the degree of thrombogenicity and, therefore, the various clinical syndromes. These risk factors can be divided into 2 groups: local vessel wall-related factors, and local (focal action) systemic factors. These risk factors include the following: 1) Rheological factors. It has been demonstrated that the more severe the stenotic lesion after plaque rupture, the higher the local shear rate with enhanced platelet deposition and thrombus formation; platelet deposition and thrombosis are particularly likely if the rupture includes the apex of the stenotic plaque, because of the high shear rate induced. 2) Degree of plaque damage. Plaque rupture produces a rough surface and stimulates an occlusive thrombus, which is enhanced depending on the degree of damage or amount of collagen type I and macrophage-dependent tissue factor exposed. 3) Residual thrombus. After spontaneous or pharmacological reperfusion, the surface of the residual thrombus is very thrombogenic and may contribute to reocclusion; this is partially due to thrombin bound to fibrin in the original thrombus. 4) Systemic factors. There is clinical and experimental evidence to suggest that 3 systemic factors at the time of plaque rupture may enhance thrombogenicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina, Unstable↗
PubMed1991

Cervical paraganglioma with subsequent intracranial and intraspinal metastases. Case report.

Paragangliomas, tumors derived from the extra-adrenal paraganglion system, have commonly been found in the retroperitoneum, abdomen, mediastinum, skull base, and neck. Rare intraspinal cases have included involvement of the cauda equina and filum terminale, and a recent case has been reported of thoracic cord paraganglioma with metastasis to the cauda equina. The authors present the case of a patient with a cervical paraganglioma who underwent subtotal resection followed by postoperative irradiation; she subsequently developed multiple intracranial and intraspinal metastases 7 months following the first decompression procedure.

Adult↗
PubMed1991

Nutrition & specialized care.

We live in a time of specialized medical care. Now, patients can find myriad healthcare centers that offer state-of-the-art treatment for their particular ailments & disabilities. As therapy regimens have become more sophisticated, so has the role food & nutrition programs play in patient care. Featured on the following pages are five programs that are tailored to patients living with chemical dependencies, eating disorders, cardiovascular disease, cancer & mental illness. In each, directors & dietitians are working actively with other healthcare professionals to provide the kind of nutritional support patients need to regain their health or, in some cases, even to survive.

Cancer Care Facilities↗
PubMed1991

[Problems raised by the administration of a peridural block in patients receiving anticoagulant therapy].

More and more patients likely to get an epidural block are treated with anticoagulant or antiplatelet drugs. An epidural hematoma may be consecutive to an injury of the epidural venous plexus. The mechanisms of action of the different drugs are reviewed. The bleeding time is not an infallible indication of aspirin or other non steroidal antiinflammatory drugs platelet defect. The protocol used in our institution for the administration of an epidural block in this group of patients is discussed.

Anesthesia, Epidural↗
PubMed1991

Regional perinatal care in crisis: a case study of an urban public hospital.

Regionalized perinatal care is intended to guarantee pregnant women and neonates access to appropriate care regardless of ability to pay. Its effectiveness depends on the willingness of hospitals to transfer high-risk patients according to established protocols and affiliations. This study examines maternal transfers (n = 896) to Cook County Hospital (CCH), a public facility and a designated perinatal center in Chicago. In 1987 and 1988, the majority (68%) of maternal transfers to CCH came from out-of-network hospitals, and 52% of these came directly from another perinatal center. The data indicate that 62% of the out-of-network transfers who delivered were medically high-risk. The study also documents the transfer of women in active labor, a violation of federal law. The term "perinatal dumping" is introduced to mean the transfer of high-risk pregnant women between hospitals for economic rather than medical reasons. Strategies for safeguarding the integrity of regionalized perinatal care are discussed.

Adolescent↗