No abstract

To identify antecedent events contributing to the development of amyotrophic lateral sclerosis, we studied 25 amyotrophic lateral sclerosis patients in whom we tabulated the incidence of factors previously associated with motor neuron disease and compared the incidences with those found in 25 hospitalized patients and 25 normal people. More amyotrophic lateral sclerosis patients reported exposure to lead and mercury, participation in athletics, and consumption of large quantities of milk. Exposure to lead and mercury, athletic participation, and milk ingestion are possible risk factors that may predispose to the development of amyotrophic lateral sclerosis.

We compared the magnetic resonance images of the tongues of 16 amyotrophic lateral sclerosis (ALS) patients with those of 20 control patients and found the tongue in ALS patients is more frequently and more severely involved than suspected clinically, with major abnormalities of size, shape, position, and internal structure. The tongue size in ALS, as measured in the sagittal plane, can be reduced by as much as two-thirds of normal. The shape of the tongue in ALS tends to be rectangular or square rather than curved as is normal. As severity of the disease increases, the position of the tongue changes so that the bulk of the muscle falls away from the incisors and no longer is in contact with the hard or soft palate. The normal radial bands from the anterior floor of the mouth to the mucosal surface are often missing in ALS as are the two curvilinear bands that run parallel to the mucosal surface and intersect the radial bands. Also, there is a mottled disorganization of the internal structure of the tongue with areas of increased and decreased signal intensity.

\s=b\ Laryngeal muscle (LM) is highly specialized for phonation and sphincter activity. We queried whether this specialization is reflected in the structure of LM. We examined, using histochemical techniques, the structure of five LM from three men who died suddenly and who had no evidence of laryngeal disease. Compared with nonlaryngeal skeletal muscle, our specimens demonstrated moderate fibrosis, rounding of fibers, basophilia, and ragged red fibers that were shown to be mitochondria. In general, LM fibers are smaller, have more variability in size, and contain a greater percentage of histochemically type 1 fibers than limb skeletal muscles. These differences suggest that theories of motor control derived from studies of limb skeletal muscles may not apply to LM. (Arch Otolaryngol 1982;108:662-666) Laryngeal muscle (LM) is highly specialized for phonation and sphincter activity. One can learn more about the mechanism of laryngeal neuromuscular function by under¬ standing the histochemical and struc¬ tural properties of LM. Since LM is highly specialized, perhaps its mor¬ phologic and metabolic characteris¬ tics are unique. One can analyze aspects of LM morphology by employ¬ ing routine stains on microscopic sec¬ tion. One can further delineate meta¬ bolic function by analyzing the tissue with particular enzyme stains, ascer¬ taining where and to what extent the enzymes congregate. Few authors have investigated this realm. Teig and his colleagues' sought to analyze laryngeal enzymatic function by eval¬ uating myofibrillar adenosine triphosphatase (ATPase) from the nondiseased side of laryngés from seven men who had unilateral laryngeal car¬ cinoma. Five of their patients had been treated with bleomycin sulfate and radiation therapy. Other au¬ thors24 evaluated motor end-plates and other factors of LM; all patients had had laryngeal carcinoma, and in many instances had received radia¬ tion treatment. To our knowledge, no study has yet been published that analyzed microscopic morphology and assays for enzymes in intrinsic LMs.In addition, the above studies evalu¬ ated human LM from diseased laryn¬ gés; local cancer and irradiation can cause histochemical changes in adja¬ cent muscle, even in the absence of tumor infiltration.5·6 We report a detailed histochemical analysis of intrinsic LMs in patients who had normal laryngés. METHODSLaryngés were removed from three adult male cadavers within six hours after death. Two subjects had suffered gunshot wounds; one had had a myocardial infarc¬ tion. All three had become acutely ill and were brought to a local emergency room, where they died. They had been ill less than 12 hours. In all cases, death was unrelated to any laryngeal trauma or dys¬ function.Following removal of the larynx, the LMs were carefully identified and dis¬ sected. The specimens were prepared according to the standard methods of Dubowitz and Brooke.5 As soon as possible after removal, the specimens were trimmed to remove any crushed or dam¬ aged tissue and embedded in 7% gum tragacanth directly on...

To evaluate the role of toxic metals in causing motor neuron disease (MND), we used a photon-excited, energy-dispersive x-ray analytical system to measure the metal content of spinal ventral horn tissue. Specimens were taken from the cervical and lumbar enlargements of 7 patients who died of MND and the results compared with those found in 12 control patients. Anterior horn lead levels were elevated in MND patients compared to controls (mean, 40.7 micrograms/gm versus 14.6 micrograms/gm; p less than 0.05) and lead levels correlated with the duration of illness (r = +0.84, p less than 0.05). Only 2 MND patients had detectable manganese levels (72.3 and 132.2 micrograms/gm) whereas 1 control had detectable manganese (14.3 micrograms/gm). One MND patient had 244 micrograms/gm selenium, but 3 controls had levels of 180, 58, and 62. Patients with the histories of greatest environmental exposure to metals during life exhibited the highest tissue levels of metals after death; despite chelation therapy for about a year, high lead levels remained in their tissue.