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Biomedical subjects

J P Cohen

Publications and source records attributed to J P Cohen.

11 recordsLinked to original sources
PubMed1999

National estimates of outdoor air toxics concentrations.

The Clean Air Act identifies 189 hazardous air pollutants (HAPs), or "air toxics," associated with a wide range of adverse human health effects. The U.S. Environmental Protection Agency has conducted a modeling study with the Assessment System for Population Exposure Nationwide (ASPEN) to gain a greater understanding of the spatial distribution of concentrations of these HAPs resulting from contributions of multiple emission sources. The study estimates year 1990 long-term outdoor concentrations of 148 air toxics for each census tract in the continental United States, utilizing a Gaussian air dispersion modeling approach. Ratios of median national modeled concentrations to estimated emissions indicate that emission totals without consideration of emission source type can be a misleading indicator of air quality. The results also indicate priorities for improvements in modeling methodology and emissions identification. Model performance evaluation suggests a tendency for underprediction of observed concentrations, which is likely due, at least in part, to a number of limitations of the Gaussian modeling formulation. Emissions estimates for HAPs have a high degree of uncertainty and contribute to discrepancies between modeled and monitored concentration estimates. The model's ranking of concentrations among monitoring sites is reasonably good for most of the gaseous HAPs evaluated, with ranking accuracy ranging from 66 to 100%.

Air Pollutants↗
PubMed1988

The role of needle aspiration biopsy in the selection of patients for thyroidectomy.

Fine needle aspiration (FNA) biopsy is gaining in popularity among all diagnostic tests used in the evaluation of patients for thyroidectomy. Its safety and accuracy have been well documented, but criteria regarding when FNA is appropriate are lacking. We retrospectively reviewed our experience with 408 consecutive patients evaluated for thyroid surgery. Two hundred seventy-three ultimately underwent thyroidectomy; 100 of these had preoperative FNA. An additional 135 patients underwent FNA without surgery. Patients who benefited from FNA were those in whom cytologic findings led to surgery for otherwise unsuspected malignancy (15), and those with asymptomatic benign nodules who avoided unnecessary thyroidectomy on the basis of FNA findings (96). FNA is superfluous when clinical conditions mandate surgery. These include nodules that arouse clinical suspicion of malignancy, massive nodules that cause aerodigestive tract compression or cosmetic disfigurement, and nodules extending into the mediastinum. All patients with asymptomatic, clinically benign thyroid nodules should undergo FNA biopsy, as approximately 50% can anticipate significant benefit from the procedure.

Biopsy, Needle↗
PubMed1986

Management of substernal and intrathoracic goiters.

Goiters that descend into the mediastinum can cause respiratory embarrassment, dysphagia, vascular compression, vocal cord paralysis, and sudden death. Although many such goiters remain clinically silent, their ability to produce sudden and unpredictable respiratory distress is well known. The condition was not considered uncommon in the first half of the twentieth century; some authors reported series of hundreds of thyroidectomies for intrathoracic goiter. Though seen less frequently today, the only effective treatment for mediastinal goiter is surgical removal. We report our experience with the management of 70 consecutive patients with substernal or intrathoracic goiters. The clinical presentation, preoperative evaluation, operative technique, and results and complications of therapy are discussed. Consideration is also given to the pathogenesis of intrathoracic extension. The transcervical approach for resection is emphasized--even goiters extending to the aortic arch were safely removed without requiring sternotomy. A multidisciplinary team approach, including the surgeon, anesthesiologist, and endocrinologist, is essential. Because of more conservative trends in the selection of patients for thyroidectomy, the incidence of mediastinal goiter may be increasing.

Adult↗
PubMed1985

Internal jugular vein thrombosis.

Internal jugular vein thrombosis is a vascular disorder that is easily overlooked or misdiagnosed. It occurs in a variety of clinical settings which disrupt normal blood flow through the internal jugular vein. Intravenous drug abusers represent a high risk group in this study. Diagnosis is readily made by computed tomography. Seven patients are presented, with discussion of the pathogenesis, clinical findings, radiologic features, potential complications, and treatment rationale.

Adult↗
PubMed1983

Reversible facial paralysis in sarcoidosis. Confirmation by serum angiotensin-converting enzyme assay.

Facial nerve paralysis is an unusual manifestation of sarcoidosis and is frequently associated with parotitis and uveitis. This triad of symptoms constitutes uveoparotid fever (Heerfordt's disease). Until recently, diagnosis was primarily clinical, aided by histologic confirmation of sarcoidosis (sarcoid of Boeck). An enzymatic assay has now been developed that seems to be specific for sarcoidosis. A case is reported herein, in which the origin of the facial paralysis was confirmed by this serum angiotensin-converting enzyme assay.

Adult↗