Search PubMed⌕ Search

Biomedical subjects

M D Cohen

Publications and source records attributed to M D Cohen.

At least 73 records · Page 4Linked to original sources
PubMed1994

Neuroblastoma invading the kidney.

Renal invasion by neuroblastoma is probably more common than is generally recognized. In this study, the incidence of renal parenchymal tumor invasion was 20.4% (10 patients) among 49 cases of abdominal neuroblastoma. Generally, the renoinfiltrative neuroblastomas were extensive and had unfavorable histological features as well as lymph node involvement; they were either stage III or IV. Tumor invasion occurred by direct penetration through the renal capsule and/or lymphatic perivascular spread. Imaging studies had 100% sensitivity and 94.9% specificity for detecting renal invasion of neuroblastoma. Surgery/pathology was the standard of reference. Two instances of misdiagnoses of renal invasion were attributed to inadequate resolution of older computed tomography films, partial volume effects, and renal distortion by tumor compression.

Abdominal Neoplasms↗
PubMed1994

Immunotoxicity of particulate lead: in vitro exposure alters pulmonary macrophage tumor necrosis factor production and activity.

Rabbit pulmonary macrophages were exposed in vitro to particulate lead oxide (PbO) for periods of up to 72 h and then assayed for the activity of tumor necrosis factor-alpha (TNF alpha) released after stimulation with lipopolysaccharide (LPS). The levels of TNF alpha obtained from PbO-treated cells were decreased in a dose-dependent manner as compared with metal-free control cells for each time point examined. Cells treated simultaneously with both LPS and PbO yielded less monokine than did cells receiving LPS alone. In addition, incubation of cell-free TNF alpha with PbO resulted in a diminution of cytotoxicity directed against TNF alpha-sensitive tumor target cells. Macrophage burdens of PbO particles increased with both the length of incubation and concentration of PbO used; increases in cellular lead burdens were paralleled by reductions in cell viability. Thus, under in vitro conditions, PbO affects the levels of the immunoregulatory monokine TNF alpha and also disrupts its cytotoxic properties after release from activated macrophages.

Animals↗
PubMed1994

Intravenous use of ionic and nonionic contrast agents in children.

PURPOSE: To determine the use of intravenous ionic and nonionic contrast agents in children. MATERIALS AND METHODS: The director of pediatric radiology at 59 of 65 large children's hospitals in North America responded to a questionnaire. RESULTS: Thirty-nine institutions used only nonionic contrast agents, one used only ionic, and 19 used both. Among those who used both, various criteria were used for selection of nonionic contrast agents. These criteria were rigidly enforced in only five of 18 institutions. The most common indication for the use of nonionic contrast agents was a severe reaction to any contrast agent, allergy, or poor renal function. Because nonionic contrast agents are more expensive, 18 of 58 directors of pediatric radiology were under pressure from hospital administrators to decrease use of these agents. The use of nonionic agents was justified because patients experienced fewer minor reactions to the agent. CONCLUSION: Most pediatric institutions are nonionic contrast agents, but many still use ionic agents for intravenous administration for selected indications.

Adult↗
PubMed1994

Staging and surveillance of children with central nervous system neoplasms: recommendations of the Neurology and Tumor Imaging Committees of the Children's Cancer Group.

Standardization of the baseline and surveillance evaluation of children with central nervous system (CNS) tumors could contribute to understanding tumor behavior, establishing prognoses, directing treatment, and interpreting multi-institutional cooperative study data. A tumor categorization schedule, based on recognized patterns of CNS tumor behavior involving 'aggressiveness' as assessed by the likelihood for neuraxis dissemination, relative time to progression and pattern of disease recurrence is presented. Included are the most common histologic subtypes of pediatric CNS neoplasms. No attempt has been made to include all histologic subtypes of pediatric CNS neoplasms. Using this categorization as a framework, recommendations are suggested for baseline evaluation at diagnosis and in surveillance.

Adolescent↗
PubMed1994

Intravenous Fluosol in the treatment of acute myocardial infarction. Results of the Thrombolysis and Angioplasty in Myocardial Infarction 9 Trial. TAMI 9 Research Group.

BACKGROUND: This study was performed to determine the safety and potential efficacy of an intravenous perfluorochemical emulsion (Fluosol) as an adjunct reperfusion therapy aimed at preventing reperfusion injury for patients with acute myocardial infarction. METHODS AND RESULTS: Patients (430) were randomized in a prospective open-labeled study, 213 to receive Fluosol and 217 to receive no Fluosol, along with 100 mg of tissue-type plasminogen activator given over 3 hours. Major end points included global ejection fraction, regional wall motion analysis, infarct size as measured by tomographic thallium imaging, and a composite clinical outcome measure. Baseline patient and angiographic characteristics were similar in the two groups. No significant difference in global ejection fraction (52% without Fluosol, 51% with Fluosol) or regional wall motion (-2.4 SD/chord with Fluosol, -2.2 SD/chord without Fluosol) was demonstrated in patients receiving Fluosol versus those not receiving Fluosol, nor was there a significant difference in thallium infarct size. Although Fluosol-treated patients with anterior infarction had an insignificantly lower mean infarct size (18.7% of the left ventricle) compared with patients with anterior infarction not treated with Fluosol (21.2% of left ventricle), this trend was not evident in the median infarct size values (22% versus 17%), left ventricular ejection fraction values (46% without Fluosol, 47% with Fluosol), or regional wall motion (-2.5 SD/chord in both groups). Rates of death and stroke were no different in the two groups; however, patients who received Fluosol experienced less recurrent ischemia. Patients receiving intravenous Fluosol had more transient congestive heart failure and pulmonary edema, perhaps because of necessary fluid administration. There was no difference in hemorrhagic complications between the two study groups. CONCLUSIONS: When given with a thrombolytic agent, Fluosol was not associated with improvement in ventricular systolic function, reduction in thallium infarct size, or overall clinical outcome. Fluosol was, however, associated with a reduction in ischemic complications and with an increase in pulmonary edema and congestive heart failure.

Adolescent↗
PubMed1994

Making the diagnosis when the patient has 'blue toes'.

Painful "blue toes" describes a physical sign whose meaning may be discovered through a carefully taken history, physical, and laboratory evaluation. Accurate diagnosis is important, because therapy for one specific condition may be contraindicated for another. When embolism is suspected, ultrasound examination of the heart, aorta, and periphery may be useful prior to angiography in order to avoid exacerbation of cholesterol crystal embolization. Transesophageal echocardiography or MRI may be needed to exclude a thoracic aortic source. The differential diagnosis can be divided into three categories: emboli from the cardiac and arterial system, acquired hypercoagulability disorders, and syndromes that lead to peripheral vascular pathology. A clinical approach to the evaluation of patients is presented, with case reports.

Aged↗
PubMed1994

Current controversy: is computed tomography scan of the chest needed in patients with Wilms' tumor?

PURPOSE: Reports from the National Wilms' Tumor Study (NWTS) Group on the subject of chest computed tomography (CT) versus chest radiograph for the detection of lung metastases from Wilms tumor are reviewed. PATIENTS AND METHODS: Thirty-two patients with lung nodules detected by CT, with negative chest radiographs, were identified. Five patients were excluded from further analysis. Of the remaining 27 patients, 18 were treated as stage IV, receiving therapy with three drugs and lung irradiation; the other nine were treated with less intensive therapy and no lung irradiation. The investigators found no significant difference between the overall survival between these two groups of patients (94% and 88%, respectively). In an earlier study, four of 11 children (36%) with normal chest radiographs and positive chest CT results were treated by ignoring the CT findings. These data compared with a relapse rate of only 20% in a control population. RESULTS: The studies do not statistically address the question of the impact of CT of the chest on survival. CONCLUSIONS: All children should have the benefit of the most sensitive imaging available, including CT, to detect tumor spread.

Humans↗
PubMed1994

Rabbit pneumothorax. Feasibility of an animal model to simulate neonatal pneumothorax.

RATIONALE AND OBJECTIVES: The feasibility of developing an animal model to simulate radiographic features of neonatal pneumothorax was investigated, and supine computed radiography (CR) and film-screen radiography (FS) images were compared. METHODS: 5-Fr pigtail catheters were inserted into the right pleural space of three New Zealand white rabbits. Two CR and two FS supine images were obtained using identical technique. After serial 4-mL injections of air, one CR and one FS supine image were obtained. The images were masked and randomized, and four radiologists reviewed the images for typical signs of pneumothorax. Chest computed tomography (CT) was performed before the injection of any air and after completion of the study. RESULTS: At zero-mL air volume, radiologists did not perceive a pneumothorax. As the air volume increased, the number of signs of a pneumothorax increased; there was no significant difference between CR and FS in the number of signs of pneumothorax detected at any volume. Chest CT confirmed that there was no unexplained air leak. The volume of air injected correlated with the calculated volume from the CT. CONCLUSIONS: This induced, volume-controlled, animal model simulated the supine radiographic features of neonatal pneumothorax.

Animals↗
PubMed1994

Providing treatment to persons with mental illness.

The RWJF Program on Chronic Mental illness created centralized mental health authorities in nine cities as a demonstration project. Evaluation teams, selected after the project began, and a national program office, established to provide technical assistance and to communicate progress and results, worked in tandem with the program staff. The project was evaluated as "logic model" to determine the feasibility of centralized authorities and to estimate their effect on various outcomes. One finding was that service reorganization does not cancel out the need to supply funds or mental health care. The problems of delay in the publication of results and of public officials' reluctance to act without "definitive" research data are described, as are the remedies for these difficulties.

Chronic Disease↗
PubMed1993

Multifocal primary neuroblastoma.

UNLABELLED: The purpose of this study is to present three patients with multifocal primary neuroblastoma, to review the literature, and describe the radiographic findings. SUBJECTS AND METHODS: Three children with multifocal neuroblastoma have been identified. The case histories and imaging findings in these patients are reviewed. RESULTS: Two children had synchronous and one child had metachronous multifocal primary neuroblastoma. The primary tumors were both in the abdomen in one patient, both in the chest in another patient, and in the chest and abdomen in the third patient. Evidence for multifocal origin of these tumors, rather than metastatic spread, is presented. CONCLUSION: Multifocal primary neuroblastomas can occur. The tumors maybe synchronous or metachronous. Awareness of this disorder may prevent errors in diagnosis and staging. Although not identified in our patients there is a strong familial incidence of neuroblastomas in those patients with multifocal tumors.

Adrenal Gland Neoplasms↗
PubMed1993

Immunotoxicity of in vitro vanadium exposures: effects on interleukin-1, tumor necrosis factor-alpha, and prostaglandin E2 production by WEHI-3 macrophages.

Treatment of cultured mouse macrophages with either of two different vanadium compounds was shown to affect the production/release of two major immunoregulatory cytokines. The pentavalent vanadium compound ammonium metavanadate was shown previously to disrupt cell-mediated immunity at the earliest stages of an in vivo anti-Listerial response, in that mice treated with vanadium displayed decreased accessory cell recruitment and numbers of activated macrophages at infection sites. To determine whether these effects were due to vanadium-induced alterations in the production of biologically-active mediators, mouse macrophage-like WEHI-3 cells were treated in vitro with ammonium metavanadate or vanadium pentoxide prior to stimulation with lipopolysaccharide endotoxin (LPS). After stimulation, monokine (tumor necrosis factor-alpha and interleukin-1) and prostaglandin E2 (PGE2) activities were assessed. Both vanadium compounds decreased recovered monokine activities; measured TNF alpha concentrations were also reduced. Spontaneous release of the IL-1/TNF-regulating prostanoid PGE2 was significantly increased by the highest concentration of vanadate tested, although LPS-stimulated PGE2 production was unaffected by either compound. These results indicate that, in vitro, pentavalent vanadium can interfere with immunoregulatory mediators critical for maintaining host immunocompetence.

Animals↗
PubMed1993

Phosphor plate computed radiography: response to variation in mAs at fixed kVp in an animal model. Potential role in neonatal imaging.

Computed digital radiography offers a number of potential advantages over conventional film-screen imaging. To determine the applicability of these to portable neonatal examinations we performed a controlled prospective study comparing conventional 200 speed film-screen with a computed radiography unit in an animal model. Images acceptable for diagnostic purposes were obtained on the digital system over an exposure range many orders of magnitude greater than was possible on the film-screen system. Digital imaging offers potential for elimination of repeat examinations due to suboptimal exposure factors, and for reduction in radiation dose to the patient. We believe that computed digital radiography should be particularly suited to portable neonatal imaging.

Animals↗
PubMed1993

A review of the toxicity of nonionic contrast agents in children.

OBJECTIVES: The safety of nonionic contrast agents with that of ionic iodinated contrast agents in children is compared. METHODS: A comprehensive literature search was conducted to identify all publications on the safety profile of nonionic contrast agents administered intravenously to children. This information was compared to published data on the safety of nonionic media in adults and on the safety of ionic agents in children. RESULTS: There appears to be strong evidence for increased safety of nonionic agents in children compared with ionic agents, although the published data reviewed are subject to methodological criticism. Moderately severe and minor reactions occur less frequently with nonionic agents. Deaths occur too infrequently to permit a valid evaluation. Contrary to previous beliefs, the incidence of adverse reactions in children appears to be similar to the incidence in adults. CONCLUSIONS: Although nonionic agents offer improved safety, it is still not clear whether this benefit justifies the associated costs, because conventional ionic agents are already extremely safe. However, it may be possible to justify the increased cost of nonionic agents in children based solely on the reduction of minor reactions. Data regarding the safety of nonionic agents in children are limited, and large, prospective studies are warranted.

Age Factors↗
PubMed1993

Mechanisms of chromium carcinogenicity and toxicity.

Chromium, like many transition metal elements, is essential to life at low concentrations yet toxic to many systems at higher concentrations. In addition to the overt symptoms of acute chromium toxicity, delayed manifestations of chromium exposure become apparent by subsequent increases in the incidence of various human cancers. Chromium is widely used in numerous industrial processes, and as a result is a contaminant of many environmental systems. Chromium, in its myriad chemical forms and oxidation states, has been well studied in terms of its general chemistry and its interactions with biological molecules. However, the precise mechanisms by which chromium is both an essential metal and a carcinogen are not yet fully clear. The following review does not seek to embellish upon the proposed mechanisms of the toxic and carcinogenic actions of chromium, but rather provides a comprehensive review of these theories. The chemical nature of chromium compounds and how these properties impact upon the interactions of chromium with cellular and genetic targets, including animal and human hosts, are discussed.

Animals↗
PubMed1992

Air reduction of an intussusception caused by a pathologic lead point in an infant.

Lead points that are the cause of an ileocolic intussusception are rare in infants [1], as is successful reduction using barium [2]. Air reduction of an intussusception with a pathologic lead point has not been previously reported. We report a case of an infant with an ileocolic intussusception secondary to a duplication cyst that was successfully reduced with air. The pathologic lead point was recognized at the time of reduction and confirmed with water-soluble contrast. Air is both a diagnostic and therapeutic contrast agent.

Air↗