Thoracoscopic excision of a posterior mediastinal "dumbbell" tumor using a combined approach.

Up to 10% of neurogenic tumors in the posterior mediastinum demonstrate intraspinal extension. Historically, these lesions have been considered resectable only by a combined thoracic and neurosurgical approach using thoracotomy. Herein, a thoracoscopic excision of a "dumbbell" lesion within the framework of a combined approach is described.

Focal retrograde amnesia following closed head injury: a case study and theoretical account.

In this paper we present data from a closed head injury patient who presents a striking example of what Kapur (Cortex 29, 217-234, 1993) has termed " focal retrograde amnesia". The patient, D.H., is unable to recollect any autobiographical incidents from the pre-morbid period, although he is able to provide personal and public information from this period. The data are discussed in relation to other reported instances of focal retrograde amnesia and a preliminary theoretical account is offered.

Immune responses to pollutant mixtures from indoor sources.

Indoor air pollution occurs as an undesirable consequence of urbanization, energy conservation, indoor bioaerosol contamination, and use of synthetic materials and new technologies, and has become a worldwide concern. It is important to comprehend not only the diversity of pollutant hazards but also to develop novel methods and approaches that establish dose-response relationships, cause-and-effect relationships, and clinical relevance. Coincident with heightened public concern over indoor air pollution and its health consequences, a revolution in immunology has occurred. The immune system is recognized as an essential defensive and homeostatic mechanism. Unfortunately, the immune apparatus is exquisitely sensitive to toxic damage. Equally important, among the disciplines available to assess the health impact of indoor air pollutants, immunology has the capability to provide sensitive and specific tools that may accurately measure relevant clinical effects at tissue, cellular, and molecular levels. Furthermore, exciting new insights into shared communications networks between the immune, endocrine, and central nervous systems may provide future explanations for the myriad human complaints associated with indoor air pollutants.

Anterior (dorsal) paraclinoid aneurysm: case report.

Saccular aneurysms arising at locations other than arterial divisions have been reported but are extremely rare. Such a case of a previously unclassified paraclinoid aneurysms that arose from the anterior (dorsal) wall of the proximal internal carotid artery is reported. The neck of this aneurysm was located distal to the junction of the ophthalmic artery, which originated in the cavernous sinus. I propose that this aneurysm be classified as an anterior (dorsal) paraclinoid aneurysm.

Rivermead Behavioural Memory Test for Children (RBMT-C): a preliminary evaluation.

This article reports the development of a children's version of the Rivermead Behavioural Memory Test (a screening test for memory impairment in adults). The test is based on memory tasks involved in normal daily life, and has four parallel versions to allow monitoring of change. Eighty-five children between the ages of 5:0 and 10:0 years each experienced two versions of the adapted test, and undertook additional intelligence and memory tests drawn from the British Ability Scales and the Wechsler Intelligence Test for Children-Revised. Performance on the adapted test correlated with Intelligence score for 5- and 6-year-olds only, with Digit Span performance for 7- and 8-9-year-olds, and with Memory score for 6-year-olds only. The results establish the feasibility of using a test of everyday memory with children as young as 5:0 years, and justify trials of the test with abnormal populations.

Posterolateral microdisectomy for cervical monoradiculopathy caused by posterolateral soft cervical disc sequestration.

The controversy over whether to use a posterior or anterior approach for surgical treatment of soft cervical discs is still largely unsettled. However, although the posterior approach may be underutilized, it has distinct advantages when there are specific indications. Out of a large pool of cases, 53 patients presented with acute monoradiculopathy caused by soft cervical disc herniation. In 36 of these, the disc was sequestered (nonconfined) and was posterolateral to the disc space as seen on computerized tomography-myelography. Distinct motor weakness was a common clinical finding in all 36 cases. These patients were treated by using a 2- to 3-cm skin incision for the posterolateral microsurgical approach. The extent of the lateral facetectomy depended upon the relationship between the nerve root and the disc. All fragments were lateral to the dural sac and were sequestered through the anulus fibrosus and the posterior longitudinal ligament. Sequestrations were removed under direct microscopic vision, but the disc space was not entered. Pain relief and motor-power improvement in the affected radicular distribution were immediate in all patients. Sensory deficit and residual motor loss improved dramatically with normalization at approximately 6 months. No complications occurred and the mean hospital stay was 2 days. The follow-up period varied from 4 to 42 months with a mean of 26 months. Thus far, there have been no recurrences or other associated complications. By using strict selection criteria and a microsurgical posterolateral approach with removal of the sequestered disc fragment, excellent results with normalization of the monoradiculopathy can be obtained. The ease of this technique, low risk, minimal complications, and excellent results make it an attractive alternative to the anterior approach. The clinical presentations, specific indications, surgical technique, and clinical results are discussed; and a prototype of a small cervical self-retaining retractor is described.

Smoking and ethylene diamine sensitization in an industrial population.

The authors studied the relationships between a history of allergy symptoms and smoking practices on respiratory sensitization to ethylene diamine (EDA) in 337 employees who had worked with it for 8 years. Thirty-eight of these had become sensitized and were reassigned to tasks not involving EDA. Responses to a mailed questionnaire yielded histories of smoking and of symptoms suggestive of allergic disease. Correlation of these histories with latency (months between first exposure to EDA and onset of respiratory symptoms) in the 38 sensitized workers revealed that current smokers had the shortest latencies, averaging 7.0 months. Persons with any history of allergic symptoms, but who had never smoked, had mean latencies of 11.3 months. Persons with histories of asthma or hay fever symptoms had mean latencies of 16.2 months and 16.7 months, respectively. Symptom-free employees who had never smoked had the longest latencies, averaging 37.3 months.

Excretion of radioactivity from rats and rabbits following cutaneous application of two 14C-labeled azo dyes.

A benzidine-derived azo dye, C.I. direct black 38 (DB38), and a p-phenylenediamine-derived dye, C.I. direct black 19 (DB19), labeled with carbon-14 in their aromatic amine moieties, were applied to the shaved dorsal skin of male Fischer-344 rats and New Zealand rabbits. Application sites were protected with nylon gauze and elastic bandage assemblies. Following application of measured amounts of radiolabeled dye in 0.1 M pH 10.2 carbonate buffer, serial urine and fecal samples were obtained from individual animals in metabolism cages at 24, 48, 72, 96, 120, and 144 h. Aliquots of urine and fecal homogenates were assayed for radioactivity by scintillation counting. Cumulative excretion of radioactivity from rats receiving DB38 was 0.05% of total dermal dose at 144 h in urine, and 0.16% of total dermal dose in feces. Cumulative excretion of radioactivity from DB38-treated rabbits at 144 h was 3.12% of total dermal dose in urine, and 5.12% in feces. From rats and rabbits receiving topical DB19, cumulative excretion of radioactivity at 144 h was less than that from DB38-treated animals. In rat urine, 0.04% of total dermal dose appeared; in rat feces, no radioactivity was recovered. In rabbit urine, 0.04% of dermal dose was found; 0.01% appeared in rabbit feces.

Toxicology of urea formaldehyde and polyurethane foam insulation.

Two types of foam insulation are in wide use. Urea formaldehyde foam is a relatively inexpensive, easily installed, and efficient insulation. Toxicity from this insulation is related to release of free formaldehyde into the home. Mild to incapacitating symptoms have been reported in occupants of urea formaldehyde-insulated homes. Airborne formaldehyde levels frequently have exceeded standards set for occupational exposure. The long-term consequences of such exposure are unknown. Because of publicity over the toxicity of urea formaldehyde foam, many physicians and patients have confused urea formaldehyde and polyurethane foam. Unlike urea formaldehyde, polyurethane foam is fully cured before construction. Toxicity occurs only during manufacture and curing. To date, there have been no reports to our knowledge of toxicity in occupants of polyurethane-insulated homes. However, toxicity caused by pyrolysis products may occur during combustion in homes insulated with either type of insulation. This report details 48 patients in whom complete medical data were obtained out of the first 100 patients contacting the Rocky Mountain Poison Center.

Diagnosis of airflow obstruction at high altitude.

Using predicted sea level values for spirometry done at high altitude, underestimation of airway obstruction may result. We therefore established spirometric normal values for an altitude of 3,100 m for white men.

Lead neuropathy in adults and children.

All parts of the nervous systems can be affected, depending on the level and duration of exposure, by increased levels of lead. The occurrence of motor neuron disease, peripheral neuropathy, and encephalopathy are not mutually exclusive disorders for those individuals suffering from the toxic effects of lead. We present data that support the concept that increased absorption of lead produces changes in both central and peripheral nervous systems. Clinical and electrical evidence of subclinical involvement of peripheral nerves appears to be common to adults and children who are exposed to lead. These observations, accumulated from several possible sources of environmental hazard, also suggest that measurement of motor nerve conduction velocity may serve as an additional factor in the diagnosis of otherwise unrecognized toxic effects of lead.

An evaluation of the Beckman chloride/carbon dioxide analyzer.

We compared the Beckman Cl/CO2 Analyzer to the American Instrument Company chloride titrator for measurement of chloride in serum, sweat, and spinal fluid. We also compared it to the Natelson gasometer and a modified continuous-flow (AutoAnalyzer) technique for measurement of carbon dioxide in serum. Effects of bilirubin and hemoglobin on results for both the CO2, and Cl were negligible. The linearity, stability, and precision of the equipment was studied. We believe the Beckman Cl/CO2 Analyzer to be ideal for simultaneous measurement of chloride and carbon dioxide in a pediatric or emergency-determination setting.

Lead in animal foods.

Analyses for lead content were carried out on 78 random samples of pet food (purchased in local grocery outlets) and on 25 individual rations for laboratory animals. The lead content of 46 samples of cat food ranged from 0.1 to 7.6 mug/g, 32 dog foods ranged from 0.1 to 3.4 mug/g, and 25 laboratory animal feeds ranged from 0.1 t0 4.0 mug/g. Foods that contain a significant amount of lead could add an uncontrolled variable to experiments using laboratory animals and may cause misinterpretation of experimental results.