Biomedical subjects

M L Kamb

Publications and source records attributed to M L Kamb.

21 records · Page 2Linked to original sources

PubMed1993

Contaminants in L-tryptophan associated with eosinophilia myalgia syndrome.

In late 1989, an epidemic of eosinophilia-myalgia syndrome (EMS) that resulted in several thousand cases of the syndrome and 36 deaths was recognized in the United States. Physicians in New Mexico linked the epidemic to the ingestion of L-tryptophan (LT). Results of studies indicated that one or more trace contaminants in LT were likely causes of the EMS epidemic. Investigators traced the LT that was taken by most patients with EMS to a single manufacturer, Showa Denko K.K. of Japan. We now report results of high performance liquid chromatographic analysis of LT samples from this manufacturer. Three sets of blind-coded samples were analyzed: the priority case lot set, which included 54 case-associated LT lots and 50 noncase-associated LT lots that were taken by case and control subjects who used only one brand of LT; the single lot case set, which included 73 case-associated LT lots and 25 noncase associated LT lots taken by case and control subjects who used only a single lot of LT; and the South Carolina tablet set, which included LT tablets taken by case subjects (n = 26) and by control subjects (n = 52). We statistically compared the concentration of each contaminant in case-associated, noncase-associated, and control samples of each sample set. The analyses showed that there were more than 60 minor contaminants in the LT from Showa Denko K.K., and that six of these contaminants were associated with EMS. The structures of three contaminants are known, but the identities of the other three contaminants are currently unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1992

Eosinophilia-myalgia syndrome in L-tryptophan-exposed patients.

OBJECTIVES: To study the incidence of eosinophilia-myalgia syndrome, the risk factors associated with the syndrome, and the clinical spectrum of illness associated with L-tryptophan use in an exposed population. DESIGN: Retrospective cohort and nested case-control studies of risk factors for eosinophilia-myalgia syndrome using inpatient and outpatient chart reviews, telephone interviews, and in-person patient interviews. Descriptive study of clinical course of L-tryptophan users. SETTING: Office practice of one psychiatrist based in a small city (population 43,467) in South Carolina. PATIENTS: Eligible subjects were all patients from the practice who used L-tryptophan during the 1989 study interval. Of these, 418 (87%) were interviewed. MAIN OUTCOME MEASURES: Clinical spectrum of illness associated with L-tryptophan use, including definite and possible cases of eosinophilia-myalgia syndrome. RESULTS: Among the 418 interviewed L-tryptophan users, we identified 47 definite cases (11%) and 68 possible cases (16%) of eosinophilia-myalgia syndrome, most of which involved patients who were using one retail brand of L-tryptophan (brand A). Among the 157 brand A users, we identified 45 definite cases (29%) and 36 possible cases (23%) of eosinophilia-myalgia syndrome, and the risk for the syndrome increased as the brand A dose increased. Fifty percent (19 of 38) of those using more than 4000 mg/day developed definite eosinophilia-myalgia syndrome, and 84% (32 of 38) developed either definite or possible eosinophilia-myalgia syndrome. On multivariate analysis, risk for definite eosinophilia-myalgia syndrome was associated with brand A dose and age of the patient; however, gender, race, and use of other medications were not associated with the syndrome. CONCLUSIONS: These results suggest that many people exposed to the agent causing eosinophilia-myalgia syndrome may develop illness, and dose of presumably contaminated L-tryptophan is the single most important predictor of eosinophilia-myalgia syndrome. The broad range of signs and symptoms reported by patients using L-tryptophan illustrates that a strict case definition may identify only about half of those affected.

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PubMed1991

Postmortem studies of the heart in three fatal cases of the eosinophilia-myalgia syndrome.

OBJECTIVE: To examine the hearts of individuals who died from the eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan, with particular attention paid to the coronary arteries, the neural structures, and the conduction system of the heart because of reported terminal disturbances of cardiac rhythm and conduction. STUDY MATERIAL: Three hearts fixed in neutral formalin and well preserved with all the relevant areas of conduction system intact. METHODS: Light microscopic examination of subserial sections of the sinus node, atrioventricular node and His bundle, coronary chemoreceptor and regional nerves, ganglia, and small coronary arteries. Routine stains used were Goldner trichrome and Verhoeff-van Gieson. RESULTS: Arterial abnormalities were numerous and primarily of two types: focal fibromuscular dysplasia causing moderate to severe narrowing, as well as endarteritis and panarteritis. Extensive examples of neuritis and ganglionitis were present throughout the heart, including the conduction system, where arterial abnormalities were also abundant. In the coronary chemoreceptor there were both old and new lesions comprising focal inflammation with degeneration as well as older areas of fibrotic destruction. Within the sinus node, areas of dense fibrosis replaced all nodal tissue. These abnormalities were similar in nature and extent in all three hearts. CONCLUSIONS: The pathologic lesions present in the coronary arteries, neural structures, and conduction system of the heart in patients who died from the eosinophilia-myalgia syndrome provide a suitable anatomic substrate for substantial cardiac electrical instability, including the occurrence of sudden death. In cases of unexplained cardiac electrical instability or sudden unexpected death an inquiry should be made about previous use of L-tryptophan. In patients with the eosinophilia-myalgia syndrome, the possibility of cardiac electrical instability should be considered as part of long-range clinical management.

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