Biomedical subjects
J Lowenstein
Publications and source records attributed to J Lowenstein.
Intraneural ganglion of the peroneal nerve: importance of timely diagnosis.
Peroneal nerve ganglion cysts typically present because of a palpable mass or symptoms and signs of entrapment neuropathy, including pain, diminished sensation, and motor weakness. Surgical treatment is usually successful when performed early, but, when diagnosis is delayed, intraneural growth and invasion may cause irreversible axonal injury and footdrop. This case report illustrates the importance of timely diagnosis when treating a ganglion of the peroneal nerve and reviews the appropriate workup, differential diagnosis, and treatment.
Fibrolipoma of the median nerve: a case report and review of the literature.
A 38 year-old patient presented with right median nerve distribution paresthesias. Electrodiagnostic studies confirmed severe carpal tunnel syndrome. A palmar mass prompted a magnetic resonance imaging scan, which suggested a fibrolipoma of the median nerve. Carpal tunnel release resulted in resolution of preoperative pain and paresthesias. We review the literature dealing with this primary nerve tumor.
Prognostic value of pharmacological stress echocardiography in patients with known or suspected coronary artery disease: a prospective, large-scale, multicenter, head-to-head comparison between dipyridamole and dobutamine test. Echo-Persantine International Cooperative (EPIC) and Echo-Dobutamine International Cooperative (EDIC) Study Groups.
OBJECTIVES: The study compared the prognostic value of dipyridamole and dobutamine stress echocardiography in patients with known or suspected coronary artery disease. BACKGROUND: Extensive information is available on the relative diagnostic accuracy of the two tests assessed in a head-to-head fashion, whereas comparative data on their prognostic yield are largely preliminary to date. METHODS: Dipyridamole (up to 0.84 mg/kg over 10 min) atropine (up to 1 mg over 4 min) (DIP) and dobutamine (up to 40 microg/kg/min)-atropine (1 mg over 4 min) (DOB) stress tests were performed in 460 patients with known or suspected coronary artery disease. Patients were followed up for 38+/-21 months. RESULTS: The DIP was negative in 253 and positive in 207 patients. The DOB was negative in 242 and positive in 218 patients. During the follow-up, there were 80 cardiac events. For all cardiac events, the negative and positive predictive value were 83% and 17% for DOB, 84% and 19% for DIP, respectively (p = NS). Considering only cardiac death, by univariate analysis Wall-Motion Score Index (WMSI) at DIP peak dose (chi-square 13.80, p<0.0002) was the strongest predictor, followed by WMSI DOB (chi2 = 8.02, p<0.004) and WMSI at rest (chi2 = 6.85, p<0.008). By stepwise analysis, WMSI at DIP peak dose was the most important predictor (RR [relative risk] 7.4, p<0.0001). CONCLUSIONS: In patients at low-to-moderate risk of cardiac events, pharmacological stress echocardiography with either dobutamine or dipyridamole allows effective and grossly comparable, risk stratification on the basis of the presence, severity and extension of the induced ischemia.
Prognostic value of myocardial viability in medically treated patients with global left ventricular dysfunction early after an acute uncomplicated myocardial infarction: a dobutamine stress echocardiographic study.
BACKGROUND: Residual viable myocardium identified by dobutamine stress after myocardial infarction may act as an unstable substrate for further events such as subsequent angina and reinfarction. However, in patients with severe global left ventricular dysfunction, viability might be protective rather than detrimental. The aim of this study was to assess the impact on survival of echocardiographically detected viability in medically treated patients with global left ventricular dysfunction evaluated after acute uncomplicated myocardial infarction. METHODS AND RESULTS: The data bank of the large-scale, prospective, multicenter, observational Echo Dobutamine International Cooperative (EDIC) study was interrogated to select 314 medically treated patients (271 men; age, 58+/-9 years) who underwent low-dose (</=10 microg x kg-1 x min-1) dobutamine for the detection of myocardial viability and high-dose dobutamine for the detection of myocardial ischemia (</=40 microg x kg-1 x min-1 with atropine </=1 mg) performed 12+/-6 days after an acute uncomplicated myocardial infarction and showing a moderate to severe resting left ventricular dysfunction (wall motion score index [WMSI] >1.6). Patients were followed up for 9+/-7 months. Low-dose dobutamine stress echocardiography identified myocardial viability in 130 patients (52%). Dobutamine-atropine stress echocardiography was positive for ischemia in 148 patients (47%) and negative in 166 patients (53%). During the follow-up, there were 12 cardiac deaths (3.8% of the total population). With the use of Cox proportional hazards model, delta low-dose WMSI (the variation between rest WMSI and low-dose WMSI) was shown to exert a protective effect by reducing cardiac death by 0.8 for each decrease in WMSI at low-dose dobutamine (coefficient, -0.2; hazard ratio, 0.8; P<0.03); WMSI at peak stress was the best predictor of cardiac death in this set of patients (hazard ratio, 14.9; P<0.0018). CONCLUSIONS: In medically treated patients with severe global left ventricular dysfunction early after acute uncomplicated myocardial infarction, the presence of myocardial viability identified as inotropic reserve after low-dose dobutamine is associated with a higher probability of survival. The higher the number of segments showing improvement of function, the better the impact is of myocardial viability on survival. The presence of inducible ischemia in this set of patients is the best predictor of cardiac death.
Hominid status of the Orce cranial fragment reasserted.
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Prognostic value of dobutamine-atropine stress echocardiography early after acute myocardial infarction. Echo Dobutamine International Cooperative (EDIC) Study.
OBJECTIVES: The aim of this multicenter, multinational, prospective, observational study was to assess the relative value of myocardial viability and induced ischemia early after uncomplicated myocardial infarction. BACKGROUND: Dobutamine-atropine stress echocardiography allows evaluation of rest function (at baseline), myocardial viability (at low dose) and residual ischemia (peak dose, up to 40 micrograms with atropine up to 1 mg) in one test. METHODS: Dobutamine-atropine stress echocardiography was performed 12 +/- 5 days (mean +/- SD) after a first uncomplicated acute myocardial infarction in 778 patients (677 men; mean age 58 +/- 10 years) with technically satisfactory rest echocardiographic study results. Patients were followed-up for 9 +/- 7 months. RESULTS: Dobutamine-atropine stress echocardiographic findings were positive for myocardial ischemia in 436 of patients (56%) and negative in 342 (44%). During follow-up, there were 14 cardiac-related deaths (1.8% of the total cohort), 24 (2.9%) nonfatal myocardial infarctions and 63 (8%) hospital readmissions for unstable angina. One hundred seventy-four patients (22%) underwent coronary revascularization (bypass surgery or coronary angioplasty). Spontaneous events occurred in 61 of 436 patients with positive and 40 of 342 patients with negative findings on dobutamine-atropine stress echocardiography (14% vs. 12%, p = 0.3). When only spontaneously occurring events were considered, the most important predictor was myocardial viability (chi-square 9.7). Using the Cox proportional hazards model, only the presence of myocardial viability (hazard ratio [HR] 2.0, p < 0.002) and age (HR 1.03, p < 0.001) were predictive of spontaneously occurring events. When only hard cardiac events were considered, age was the strongest predictor (chi-square 3.6, p = 0.056), followed by wall motion score index (WMSI) at peak dose (chi-square 3.3, p = 0.06) and remote ischemia (chi-square 2.25, p = 0.1). When cardiac death was considered, WMSI at peak dose was the best predictor (HR 9.2, p < 0.0001). CONCLUSIONS: During dobutamine stress, echocardiographic recognition of myocardial viability is more prognostically important than echocardiographic recognition of myocardial ischemia for predicting unstable angina, whereas WMSI at peak stress was the best predictor of cardiac-related death. Different events can be recognized with different efficiency by various stress echocardiographic variables.
Wear of retrieved cemented polyethylene acetabula with alumina femoral heads.
Four yttrium-stabilized alumina ceramic-on-polyethylene articulations obtained from patients who were undergoing revision surgery for sepsis (3) or recurrent dislocation (I) between 34 and 73 months were evaluated to assess their in vivo wear performance. The annual volumetric wear of the acetabular components determined directly by a fluid displacement method ranged from 58 to 140 mm3/y. Scanning electron microscope examination of these four ceramic heads revealed similar surface damage in all cases from a variety of causes. These included differential granular wear (alumina grains and yttrium-stabilized alumina grains at different depths), multidirectional scratches with heaped up boundaries, and incompletely sintered grains, as well as the formation of craters and separation of grain boundaries. The femoral heads in this small series of revision cases show that yttrium-stabilized alumina ceramic heads may develop surface irregularities from either manufacturing processes or in vivo use. The wear rates of this type of alumina-on-polyethylene articulation up to the time of revision were not substantially different from those found in other metal-on-polyethylene articulations retrieved at revision surgery.
Role of stress echocardiography in risk stratification early after an acute myocardial infarction. EPIC (Echo Persantin International Cooperative) and EDIC (Echo Dobutamine International Cooperative) Study Groups.
Resting and stress echocardiography is a 'one-stop shop', which enables a wide range of information to be collected on resting function, myocardial viability, and induced ischaemia, all of which are useful for prognostic stratification. Large scale, multicentre, prospectively collected data show the prognostic failure of resting function and inducible ischaemia, both independently and combined, which are especially effective in predicting cardiac death. The GISSI data show that the increment of risk as a result of reduction in ventricular function has a hyperbolic trend, with a relatively moderate increase in mortality for ejection fraction values between 50 and 30%, but with marked increases below 30%. The EPIC data show that the 1-year risk of cardiac death is as low as 2% in patients with negative dipyridamole stress echocardiography: it doubles if the test is positive at a high dose, and is almost four times higher if it is positive at a low dose. In the field of prognostic stratification, in the absence of carefully controlled studies, the choice between coronary angiography as the only essential study, or use of a non-invasive test to discriminate access to catheterization currently reflect alternate philosophical approaches rather than scientifically based decisions. In the invasive approach, stress echocardiography offers relief from the vicious circle of chest pain-coronary angiography revascularization. In the non-invasive and physiological approach, stress echo is capable of offering, in one sitting, an insight into the main determinants of survival: function, viability, and ischaemia.
In vivo skeletal responses to porous-surfaced implants subjected to small induced motions.
Cylindrical porous-coated implants were placed in the distal femoral metaphyses of twenty dogs and were subjected to zero, twenty, forty, or 150 micrometers of oscillatory motion for eight hours each day for six weeks with use of a specially designed loading apparatus. The in vivo skeletal responses to the different magnitudes of relative motion were evaluated. Histological analysis demonstrated growth of bone into the porous coatings of all of the implants, including those that had been subjected to 150 micrometers of motion. However, the ingrown bone was in continuity with the surrounding bone only in the groups of implants that had not been subjected to motion or that had been subjected to twenty micrometers of motion; in contrast, the implants that had been subjected to forty micrometers of motion were surrounded in part by trabecular bone but also in part by fibrocartilage and fibrous tissue, and those that had been subjected to 150 micrometers of motion were surrounded by dense fibrous tissue. Trabecular microfractures were identified around three of the five implants that had been subjected to forty micrometers of motion and around four of the five that had been subjected to 150 micrometers of motion, suggesting that the ingrown bone had failed at the interface because of the large movements. The architecture of the surrounding trabecular bone also was altered by the micromotion of the implant. The implants that had stable ingrowth of bone were surrounded by a zone of trabecular atrophy, whereas those that had unstable ingrowth of bone were surrounded by a zone of trabecular hypertrophy. The trabeculae surrounding the fibrocartilage or fibrous tissue that had formed around the implants that had been subjected to forty or 150 micrometers of motion had been organized into a shell of dense bone tangential to the implant (that is, a neocortex outside the non-osseous tissue).
Ethical issues and relationships between house staff and attending physicians: a case study.
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The atropine factor in pharmacologic stress echocardiography. Echo Persantine (EPIC) and Echo Dobutamine International Cooperative (EDIC) Study Groups.
OBJECTIVES: This study sought to compare, head to head, the two most popular pharmacologic stress echocardiographic tests--dipyridamole and dobutamine--with state of the art protocols in a large multicenter prospective study. BACKGROUND: In the continuing quest for ideal diagnostic accuracy, pharmacologic stress echocardiography has quickly moved over the years from low to high dose regimens and is currently performed with atropine coadministration. METHODS: Dobutamine (up to 40 microgram/kg body weight per min) plus atropine (up to 1 mg over 4 h) and dipyridamole (up to 0.84 mg/kg per min over 10 h) plus atropine (up to 1 mg over 4 h) stress echocardiography was performed on different days, in random order and within 1 week in 360 patients with chest pain syndrome. Thirteen different echocardiographic laboratories, all fulfilling quality control criteria for stress echocardiographic reading, contributed to the study. RESULTS: No major complications occurred during either test. The test was interrupted before achievement of predetermined end points for limiting side effects in 37 dobutamine-atropine and 7 dipyridamole-atropine stress echocardiographic studies (feasibility 90% vs. 98%, p < 0.01). Diagnostic accuracy was assessed in a subset of 110 patients with no obvious rest dyssynergy (akinesia or dyskinesia) who underwent coronary angiography independently of test results and within 1 week of testing. Significant coronary artery disease (> or = 50% diameter reduction in at least one major coronary vessel by quantitative coronary angiography) was found in 92 patients. Sensitivity for detection of coronary artery disease was 84% (77 of 92) for dobutamine-atropine and 82% (75 of 92) for dipyridamole-atropine stress echocardiography (p = NS), with a specificity of 89% (16 of 18) for dobutamine-atropine and 94% (17 of 18) for dipyridamole-atropine stress echocardiography (p = NS). A significant correlation was present between peak wall motion score index during dipyridamole-atropine and dobutamine-atropine stress echocardiography (r = 0.83, p < 0.0001). CONCLUSIONS: Dobutamine-atropine and dipyridamole-atropine stress echocardiography are safe and feasible, although submaximal studies are more frequent with dobutamine. The two stresses have comparable accuracy in the detection of angiographically assessed coronary artery disease, although dobutamine is marginally more sensitive and dipyridamole marginally more specific. Stratification of the ischemic response in the space domain is also comparable with the two stresses.
Stimulatory influence of soy protein isolate on breast secretion in pre- and postmenopausal women.
Soy foods have been reported to have protective effects against premenopausal breast cancer in Asian women. No studies have been reported on potential physiological effects of dietary soy consumption on breast gland function. We evaluated the influence of the long-term ingestion of a commercial soy protein isolate on breast secretory activity. We hypothesized that the features of nipple aspirate fluid (NAF) of non-Asian women would be altered so as to resemble those previously found in Asian women. At monthly intervals for 1 year, 24 normal pre- and postmenopausal white women, ages 30 to 58, underwent nipple aspiration of breast fluid and gave blood and 24-h urine samples for biochemical studies. No soy was administered in months 1-3 and 10-12. Between months 4-9 the women ingested daily 38 g of soy protein isolate containing 38 mg of genistein. NAF volume, gross cystic disease fluid protein (GCDFP-15) concentration, and NAF cytology were used as biomarkers of possible effects of soy protein isolate on the breast. In addition, plasma concentrations of estradiol, progesterone, sex hormone binding globulin, prolactin, cholesterol, high density lipoprotein-cholesterol, and triglycerides were measured. Compliance was assessed by measurements of genistein and daidzein and their metabolites in 24-h urine samples. Excellent compliance with the study protocol was obtained. Compared with NAF volumes obtained in months 1-3, a 2-6-fold increase in NAF volume ensued during months 4-9 in all premenopausal women. A minimal increase or no response was found in postmenopausal women. No changes were found in plasma prolactin, sex hormone binding globulin, cholesterol, high density lipoprotein cholesterol, and triglyceride concentrations. Compared with concentrations found in months 1-3 (no soy), plasma estradiol concentrations were elevated erratically throughout a "composite" menstrual cycle during the months of soy consumption. No significant changes were seen in plasma progesterone concentrations. No significant changes were found in plasma estrogen levels in postmenopausal women. A moderate decrease occurred in the mean concentration of GCDFP-15 in NAF in premenopausal women during the months of soy ingestion. Of potential concern was the cytological detection of epithelial hyperplasia in 7 of 24 women (29.2%) during the months they were consuming soy protein isolate. The findings did not support our a priori hypothesis. Instead, this pilot study indicates that prolonged consumption of soy protein isolate has a stimulatory effect on the premenopausal female breast, characterized by increased secretion of breast fluid, the appearance of hyperplastic epithelial cells, and elevated levels of plasma estradiol. These findings are suggestive of an estrogenic stimulus from the isoflavones genistein and daidzein contained in soy protein isolate.
The multicentre trial philosophy in stress echocardiography: lessons learned from the EPIC study. EPIC-EDIC Study Project. Echo Persantine International Cooperative Study. Echo-Dobutamine International Cooperative Study.
The scientific assessment of diagnostic tests should not be based upon a small series of results published by the best academic institutions, but ought to require large scale, multicentre validation founded on grass roots institutions with real doctors, real patients and real problems. To this purpose, an international network of stress echo laboratories has been organized, and within a few years has collected data from thousands of studies using pharmacological stress echocardiography, performed with either dipyridamole (EPIC: Echo Persantine International Cooperative Study) or dobutamine (EDIC: Echo Dobutamine International Cooperative Study) stresses. In a widely deregulated field, all network laboratories have agreed: to pass a quality control examination on stress echo reading before entering the study; to adopt an identical drug infusion protocol; to code similarly the LV segments; and to adopt a common scoring system for wall motion analysis. A minimum amount of historical, clinical, and-when available-stress electrocardiographic, angiographic and follow-up data have been collected on each patient, and disseminated in the various centres, facilitating the creation of an international stress echo language that will help, not only the production of high quality scientific data, but also the build up of a common stress echo lab, with a standardized way of making the studies, unifying the methods and terminology, and archiving data. To date, we have 50 echo laboratories from 15 nations across four continents (Europe, America, Asia and Africa) actively involved in this project. These data will ultimately fill the gap between the academic theory of journals and the pragmatic experience of daily life in a busy echocardiographic laboratory.
Ranitidine-associated interstitial nephritis and Fanconi syndrome.
Ranitidine is an H2 blocking agent widely used in the treatment of peptic ulcer disease. Although acute interstitial nephritis has been described in association with a related drug, cimetidine, this complication secondary to ranitidine has been reported only once before. We describe a patient who presented with acute renal failure and features of Fanconi syndrome in association with the use of ranitidine. Renal biopsy showed acute interstitial nephritis. The patient had renal tubular acidosis with alkaline urine, aminoaciduria, renal glycosuria, uricosuria, and phosphaturia. There was a marked disparity between the degree of elevation of urea nitrogen and creatinine concentrations in the serum that was attributable to diminished urea generation, since simultaneous measurement of inulin, creatinine, and urea clearances showed that they were comparably reduced. Urinary nitrogen loss in the form of aminoaciduria contributed significantly to decreased urea generation. Both acute renal failure and Fanconi syndrome resolved after treatment with prednisone.
[Cytologic changes in bronchoalveolar lavage in amiodarone treated patients].
The histologic evidence of amiodarone pulmonary toxicity is interstitial pneumonia with foamy alveolar macrophages, which ultrastructurally show lamellar inclusion bodies due to lipid storage. Bronchoalveolar lavage (BAL) fluid findings include foamy macrophages, considered characteristic, and, in certain patients, differential cell counts suggestive of active alveolitis, giving rise to an immunologic explanation for its origin. The present study was undertaken in order to investigate the findings in BAL fluid in nontoxic patients taking amiodarone and to evaluate their clinical relevance. Eleven patients taking amiodarone chlorhydrate for severe ventricular arrhythmias (345 +/- 129 mg/day during 46 +/- 31 months and an accumulated dose of 440 +/- 337 g) and without clinical or radiological evidences of pulmonary toxicity, were clinically evaluated and studied by BAL. As shown in Table 1, cough and pulmonary rales were common findings (64% and 36% respectively), chest X-Rays were normal or indicative of cardiac failure and arterial blood gases showed slight hypoxemia (PaO2 83 +/- 10). As these are usual findings in advanced cardiac diseases, the patients were considered as having no amiodarone toxicity. BAL was done and the fluid obtained was processed for cytologic study. In every patient foamy macrophages were seen with light microscopy and lamellar bodies were detected by electron microscopy. In 5/10 evaluable patients BAL fluid cell count disclosed an increase in lymphocytes, leukocytes or both, indicative of alveolitis. This group of patient had lower PaO2 and PaO2/PAO2 than "non alveolitic" patients (76 +/- 9 mmHg vs 89 +/- 5 mmHg and 0.72 +/- 0.1 vs 0.85 +/- 0.08 - p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Refractory hypertension: definition, prevalence, pathophysiology, and management.
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Blood pressure and blood pressure variability following withdrawal of propranolol and clonidine.
The effects of placebo, propranolol, and clonidine on blood pressure and blood pressure variability were examined in 14 subjects who had moderate essential hypertension. Hydrochlorothiazide was given throughout successive 4- to 5-week periods of placebo, propranolol, and clonidine administration. During each treatment period, subjects were admitted twice to the clinical research unit for 24-hour blood pressure monitoring performed during administration of placebo, propranolol and clonidine and repeated 1 to 2 weeks later during the first 24 hours after the abrupt cessation of placebo or drug administration. Blood pressure was recorded at 15-minute intervals using an automated noninvasive recorder (Arteriosonde, Roche, New Jersey). Systolic and diastolic blood pressure readings were averaged and the standard deviation taken as the measure of long-term variability (LTV). Systolic and diastolic blood pressure in sequential overlapping blocks of seven readings were averaged and the standard deviation calculated. Short-term variability (STV) was estimated as the average of the standard deviations of the running means. During placebo administration and withdrawal, systolic and diastolic blood pressures as well as LTV and STV were unchanged. Systolic and diastolic pressures did not differ during propranolol administration from those during propranolol withdrawal or placebo withdrawal. Systolic and diastolic LTV and STV did not differ during propranolol administration and withdrawal from those observed during placebo administration or withdrawal. After clonidine withdrawal, both systolic and diastolic pressures increased to values significantly greater than during clonidine administration. These values were significantly greater than those observed after placebo withdrawal, thereby indicating rebound hypertension. After clonidine withdrawal, seven of fourteen subjects developed systolic pressure rebound; diastolic pressure rebound was observed in three patients.(ABSTRACT TRUNCATED AT 250 WORDS)