L-tryptophan-associated eosinophilic fasciitis prior to the 1989 eosinophilia-myalgia syndrome outbreak

OBJECTIVE

To investigate the relationship between L-tryptophan (LT) ingestion and eosinophilic fasciitis (EF) occurring prior to the outbreak of eosinophilia-myalgia syndrome in 1989.

METHODS

Interviews and record reviews of 45 EF case-patients and 126 polymyositis patients (controls) diagnosed prior to 1988.

RESULTS

Nine case-patients (20%) and no controls recalled taking LT before onset of the disease (odds ratio = infinity, 95% confidence interval = 8.3-infinity). Among EF case-patients, LT ingestion was associated with dyspnea.

CONCLUSION

LT ingestion was associated with EF prior to the 1989 outbreak of eosinophilia-myalgia syndrome. Lung abnormalities may be a distinguishing feature of LT-mediated illness.

Effects of tryptophan supplementation to a maize-based diet on lipid metabolism in laying hens

1. Experiments were conducted with laying hens to determine the effects of supplementing 0, 1.0, 2.0 and 3.0 or 4.0 g trp/kg diet to a maize and soyabean meal-based laying ration (basal tryptophan = 1.66 g/kg) on tissue lipid concentrations. 2. Plasma cholesterol, triglycerides and nonesterified fatty acids were increased by supplementing the diet with 1.0 g trp/kg diet and decreased with 3.0 or 4.0 g trp/kg diet. A significant quadratic effect of supplemental tryptophan was observed on plasma lipids in most cases. The observed effects diminished with time. No consistent changes were observed in plasma glucose concentrations. 3. Total liver lipids were reduced by supplemental tryptophan at all concentrations.

Route of administration of tryptophan and tyrosine affects short-term food intake and plasma and brain amino acid concentrations in rats

The effects of route of administration of tryptophan and tyrosine on food intake and diet selection and on plasma and brain tryptophan or tyrosine concentrations were studied. Tryptophan and tyrosine given intraperitoneally at 100 mg/kg body wt suppressed food intake by 33-45% over a 2-h feeding period beginning 30 min after injections. No preferential effect was shown for either the high carbohydrate or high protein diet choice. When given intragastrically at this dose, neither tryptophan nor tyrosine affected food intake. Tryptophan, but not tyrosine, at 200, 400 and 600 mg/kg body wt given intragastrically reduced food intake and carbohydrate diet intake by an average of 20 and 25%, respectively, in the first 2 h of feeding. Plasma and brain tryptophan were higher for 30 min following intraperitoneal tryptophan injections than after tryptophan given intragastrically at 100 mg/kg body wt. However, intraperitoneal tyrosine (100 mg/kg body wt) resulted in higher plasma tyrosine levels at 5-10 min but lower levels at 30 min than when tyrosine was given intragastrically. Brain tyrosine was higher after intraperitoneal treatment only at 10 min and was similar to intragastric treatment at other times. When these amino acids were given intragastrically at 400 mg/kg body wt, higher plasma tryptophan, plasma tyrosine and brain tyrosine were found than following intraperitoneal injection of the behaviorally effective dose (100 mg/kg body wt) at 30 min. Thus the reduced effect on food intake of tryptophan or tyrosine given intragastrically compared with intraperitoneally is not readily explained by their lower concentrations in plasma and brain preceding and at the time that the rats had access to food.

The metabolic fate of infused L-tryptophan in men: possible clinical implications of the accumulation of circulating tryptophan and tryptophan metabolites

L-Tryptophan (Trp) was widely used as a natural tool for the support of serotonin-mediated brain functions and as a challenge probe for the assessment of serotonin-mediated neuroendocrine responses. The metabolic fate of the administered Trp and the kinetics of the accumulation of Trp metabolites in the circulation, however, have never thoroughly been investigated. This study describes the time- and dose-dependent alterations in the plasma levels of various Trp metabolites and large neutral amino acids after the infusion of Trp to healthy young men (1, 3 and 5 g; placebo-controlled, double-blind, cross-over study during day- and night-time). The major Trp metabolites (kynurenine, indole acetic acid and indole lactic acid) in plasma increased dose-dependently but rather slowly after Trp administration to reach their maximal plasma levels (up to 10-fold after the 5 g dose) at about 3 h p.i., and remained at an elevated level (about 5-fold) for up to 8 h. N-acetyl-Trp and 5-hydroxy-Trp rose rapidly and massively after Trp infusions, at the 5 g dose more than 200- and 20-fold, respectively, and declined rapidly to about 5-fold baseline levels within 2 h. Whole blood serotonin levels were almost unaffected by the Trp infusions. A rather slow increase of 5-hydroxyindole acetic acid was seen, reaching maximum values (3-fold at the 5 g dose) at about 2 h after the infusion of Trp. Additionally, a dose-dependent rise of circulating melatonin was observed after L-Trp infusions. The administration of L-Trp caused a depletion of the concentrations of the other large neutral amino acids and a dose dependent decrease of the ratio between plasma tyrosine and the sum of the plasma concentrations of the other large neutral amino acids. Apparently, none of the existing pathways of peripheral Trp metabolism is saturated by its substrate, Trp in men. At least some of the central effects reported after L-Trp administration may be mediated by the Trp-stimulated formation of neuroactive metabolites or by the decreased availability of tyrosine for catecholamine synthesis.

[Eosinophilia-myalgia syndrome with fasciitis and interstitial myositis after L-tryptophan administration]

We describe a 53-year-old women with eosinophilia-myalgia syndrome who suddenly developed severe persistent myalgias of her arms, legs, back, and shoulder after a 5-month period of daily L-tryptophan ingestion, associated with fever, progressive stenocardia and left-sided congestive heart failure. Laboratory tests showed a leukocytosis of 11.2/nl with 3.14/nl eosinophils and an elevated erythrocyte sedimentation rate. There was a marked, predominantly proximal sclerosis of her arms, legs and trunk with a brownish discoloration. The skin of her arms and legs appeared dimpled (peau d'orange). Findings of the electrophysiological examinations were consistent with sensory neuropathy and myositis. Remarkable fasciitis and interstitial myositis were present in a biopsy specimen (from skin to muscle) taken from her thigh. However, eosinophilic infiltrates were rare. Angiography revealed an apical obstructive cardiomyopathy. In this paper, we describe the clinical findings, the course over 2 years, as well as the therapeutic management. Furthermore, the most important differential diagnoses are discussed and the literature is reviewed with special attention given to more recent pathogenic insights into this newly recognized multisystem disease.

Autoantibodies to nuclear lamin C in the eosinophilia-myalgia syndrome associated with L-tryptophan ingestion

OBJECTIVE

To examine the autoantibodies (antinuclear antibodies [ANA]) present in serum from a patient with eosinophilia-myalgia syndrome (EMS).

METHODS

Sera obtained during the early phase of EMS and following therapy with prednisone were screened by indirect immunofluorescence on HEp-2 cells, and ANA were characterized by immunoblotting on a purified nuclear lamin fraction.

RESULTS

ANA with a ring-like pattern of nuclear staining were identified at high titer by immunofluorescence, and immunoblotting experiments showed them to be directed against lamin C. The antibody titer declined dramatically after discontinuation of L-tryptophan and therapy with prednisone.

CONCLUSION

This is the first characterization of an antigen/autoantibody system associated with EMS. The findings indicate that this EMS-associated autoantibody recognizes epitopes localized in the carboxyterminal region of lamin C. The occurrence of anti-lamin C autoantibodies in one EMS patient expands the spectrum of clinical conditions associated with these antibodies, and provides evidence for an autoimmune response in EMS.

Effect of tryptophan administration on circulating melatonin levels in chicks and rats: evidence for stimulation of melatonin synthesis and release in the gastrointestinal tract

The administration of L-tryptophan (Trp, 150-300 mg/kg) to rats and chicks causes a rapid and dose-dependent elevation of circulating melatonin. The elevation of serum melatonin was greater after oral compared to the intraperitoneal route of administration of the same dose of Trp (150 mg/kg). The Trp-induced increase of circulating melatonin was unaffected by prior pinealectomy but was almost abolished by a partial ligature of the portal vein. The Trp-induced increase of melatonin in the portal blood preceded that in the systemic circulation. The gut contains considerable amounts of melatonin and the Trp-induced elevation of melatonin was greater in the duodenum compared to the pineal or the blood. The enterochromaffin cells of the gastrointestinal tract appear to be the major source of the Trp-induced increment of circulating melatonin. The possibility is discussed that the sedating, sleep inducing effects of Trp are mediated by the Trp-induced elevation of circulating melatonin.

Oral amino acids and gastric emptying: an investigation of the mechanism of levodopa-induced gastric stasis

To investigate possible mechanisms of levodopa-induced gastric stasis, we have studied the effect of other amino acids on gastric emptying. The large neutral amino acid tryptophan delays gastric emptying in the dog at molar concentrations below those required to stimulate duodenal osmoreceptors. In healthy volunteers, we have shown that neither tryptophan nor the small neutral amino acid glycine delayed gastric emptying when given in concentrations similar to those of levodopa which produce gastric stasis. The study suggests that levodopa does not inhibit gastric emptying by an effect on duodenal amino acid receptors or via osmoreceptors.

Amino acid supplementation of meat meal in lysine-fortified, corn-based diets for growing-finishing pigs

Three experiments involving 320 Yorkshire x Hampshire pigs were conducted to assess the effects of L-tryptophan additions to meat meal-supplemented, corn-based diets on rate and efficiency of growth of growing-finishing pigs. The meat meal used in Exp. 1 and 2 was a blend from two sources and that used in Exp. 3 was from a single source. A fortified corn-soybean meal basal diet (13.3% CP during the growing stage; 11.7 or 12.0% CP during the finishing stage), supplemented with .15 to .20% lysine (as L-lysine.HCl), was fed in each experiment. This diet was formulated to be adequate in dietary lysine (.75 to .80% during the growing stage; .65 to .71% during the finishing stage). Meat meal was added at 5 to 10% and was substituted for corn and soybean meal on a lysine basis. Diets containing meat meal were then supplemented with various levels (0 to .05%) of L-tryptophan. Levels of Ca and P were approximately the same across treatments, with levels based on the amounts provided by the highest level of meat meal in the diets. The pigs initially averaged 24, 29, and 45 kg of BW in the three experiments, and they were on test until they reached market weight (93 to 101 kg of BW). Pigs were switched from the growing to the finishing diet at 57 and 61 kg in Exp. 1 and 2, respectively. Feed intake, growth rate, and efficiency of feed utilization were reduced when meat meal was included in the diet, particularly at the higher dietary inclusion (10%).(ABSTRACT TRUNCATED AT 250 WORDS)

Research note: feed restriction in broiler breeders causes a persistent elevation in corticosterone secretion that is modulated by dietary tryptophan

The corticosterone response of immature broiler breeder males to feed restriction and the administration of increased levels of dietary Trp was investigated. Corticosterone levels were significantly (P less than .01) higher in birds placed on a skip-a-day (SD) feed restriction regimen from 4 to 15 wk of age than in birds fed an ad libitum intake. Elevated levels in SD birds persisted for the duration of the study. Levels were also higher in SD birds on those days on which feed was withheld (FEED-OFF) than on those days on which feed was delivered (FEED-ON). The SD males consuming a diet containing 1.5% Trp showed a change in the pattern of hormone secretion as compared with SD control birds (.19% Trp), with corticosterone levels increasing on the FEED-ON days and decreasing on the FEED-OFF days. It is concluded that SD feed restriction causes a persistent elevation of plasma corticosterone in broiler breeders. The secretory pattern of corticosterone can be modulated by increasing the Trp content of the diet, possibly as a result of reciprocal interactions between the serotonergic system and the hypothalamic-pituitary-adrenal axis.

Fluoxetine potentiation by buspirone: three case histories

The potentiation of fluoxetine by buspirone is described in three cases of treatment-resistant depression. All three patients improved markedly with very few side-effects from the medication. The possibility of synergy between drugs that affect serotonin reuptake inhibition, 5HT1A receptors and 5HT2 receptors is discussed.

Serotonin function and depression: neuroendocrine and mood responses to intravenous L-tryptophan in depressed patients and healthy comparison subjects

OBJECTIVE

This study was designed to compare central serotonergic function in depressed patients and healthy comparison subjects by examining neuroendocrine and mood responses to intravenous L-tryptophan.

METHOD

One hundred twenty-six drug-free patients with DSM-III-R major depression (109 unipolar, 17 bipolar; 68 melancholic, 58 nonmelancholic; 28 psychotic, and 98 nonpsychotic patients) and 58 healthy comparison subjects participated. After an overnight fast, subjects received an intravenous infusion of L-tryptophan, 7 g. Blood was obtained for determination of serum prolactin, serum growth hormone (GH), and plasma tryptophan levels. Visual analogue scales were used to assess mood.

RESULTS

Prolactin responses were blunted in nonmelancholic and higher in melancholic and psychotic depressed patients, while GH responses were blunted in combined unipolar, nonmelancholic, and nonpsychotic depressed patients. Controlling for baseline biological, clinical, and demographic factors eliminated the higher prolactin response in the melancholic and psychotic patients, attenuated the blunted GH response in the unipolar patients, and revealed a blunted GH response in the melancholic patients. Patients and comparison subjects differed on five of 13 mood responses, primarily because of baseline differences.

CONCLUSIONS

These findings are consistent with previous studies demonstrating blunted neuroendocrine responses to intravenous L-tryptophan in depression. Restriction of these findings to specific subtypes of depression may reflect a differential role of serotonergic abnormalities in these subtypes.

Effect of dietary tryptophan on muscle, liver and whole-body protein synthesis in weaned piglets: relationship to plasma insulin

Two experiments were carried out with piglets, 3-5 kg live weight, to evaluate the effects of feeding a tryptophan (TRP)-deficient diet for 2 weeks on protein synthesis rates measured in vivo 2 h after a meal. In the first experiment on twenty piglets fed on 250 g protein/kg diets, TRP deficiency (0.77 g/16 g nitrogen) as compared with adequacy (1.17 g/16 g N) significantly decreased feed intake, growth performance and fractional protein synthesis rates (FSR), without variation of RNA in longissimus dorsi (LD) and with parallel increases in RNA in semitendinosus (ST) muscle and liver. In the second experiment thirty-two piglets were tube-fed deficient and adequate diets at the two feeding levels (LF) previously achieved. Both TRP and LF significantly increased growth performance and FSR, but not RNA, in LD and ST muscle, with a trend to a synergy between the two factors (TRP x LF interaction). In another muscle, trapezius (TR), the same interaction was only apparent in RNA content. Among the three muscles it was in LD that FSR was the most responsive to dietary TRP (significant muscle x TRP interaction). In the liver the TRP x LF interaction on FSR and not RNA was the major significant effect, indicating that higher TRP and higher LF were both required to get the maximum protein synthesis rate. At 30 min after a meal the same significant interaction effect was shown on plasma glucose, whilst the higher LF increased plasma insulin with both diets. After a further 30 min the appearance of a similar significant effect of the TRP x LF interaction on plasma insulin resulted from its abatement when the deficient diet had been fed at high LF. These results suggest that dietary TRP deficiency decreased muscle and liver protein synthesis rates in relation to a decrease in the post-prandial release of insulin following a decreased rate of nutrient absorption.

Histidine and tryptophan requirement of growing chicks

Experiments were conducted to determine the His and Trp requirement of broiler chicks during the period 8 to 22 days posthatching. A His- or Trp-deficient diet (.32% total His; .18% total Trp; 25% CP; 3,200 kcal MEn/kg) based upon corn, feather meal, and soybean meal was supplemented with graded increments of either L-His.HCl.H2O or L-Trp to produce growth responses. Growth rate and feed efficiency of birds fed the fully fortified experimental diet were similar to those of birds fed a corn and soybean meal positive control diet (23% CP; 3,200 kcal MEn/kg). True digestibility of the protein blend (corn, feather meal, and soybean meal) used in the basal diet was 81.4% for His and 83.3% for Trp as established in precision-fed, cecectomized adult cockerels. Requirements for digestible His and Trp were determined to be not greater than .31% (1.24% of CP) and .20% (.80% of CP), respectively, for maximal weight gain and feed efficiency. Translating the requirement estimates to practice, wherein a 23% corn and soybean meal diet would be fed, results in a total His requirement of .32% and a total Trp requirement of .22% of the diet during the broiler chick's 2nd and 3rd wk of life.

[Polyneuropathy and fasciitis in eosinophilia-myalgia syndrome]

Eosinophilia-Myalgia-Syndrome (EMS), a newly recognized illness, was described first in October 1989, when it formed an epidemic in the USA and later also in Europe. In the meantime, ingestion of L-tryptophan containing products has been recognized to trigger this syndrome, but the pathophysiological basics are still subject to speculation. Often starting with a flu-like period, the disease is dominated by dermatologic (fasciitis) and neurologic (neuropathy, myopathy) symptoms in the subsequent stages. Reporting on an own case and reviewing the literature, clinicopathological aspects and the problems of treatment are discussed. In contrast with the majority of published cases, which showed predominance of axonal damage, our patient displayed the clinical and electro-physiologic characteristics of demyelinating neuropathy.

Impact of dietary tryptophan and behavioral type on behavior, plasma cortisol, and brain metabolites of young pigs

The behavioral reactivity in an "open-field" test and plasma cortisol levels were studied in 72 pigs from 12 litters fed for 3 wk one of three diets with different levels of tryptophan: deficient (.14%), adequate (.23%), or excess (.32%). "Open-field" tests were performed three times: 5 d (day W + 5), 23 d (day W + 23) and 45 d (day W + 45) after weaning. The exploration time and the number of grunts provided an adequate measure of the individual emotional reactivity at day W + 5. Significant correlations were obtained between exploration time and the number of grunts at each time (r = -.83 at day W + 5; r = -.46 at day W + 23; r = -.71 at day W + 45). The distinction between animals remained (P less than .05) in terms of exploration time at both 23 and 45 d after weaning. At day W + 23, exploration time was lower in the group fed the adequate diet than in the two other groups. This effect was maintained subsequently after feeding all pigs the same adequate diet (day W + 45). In 36 pigs slaughtered at day W + 23, brain TRP concentration was higher with the excess dietary TRP than with deficient or adequate levels. Conversely, other plasma amino acids (particularly threonine) accumulated only in the brains of pigs fed the deficient diet. Plasma cortisol level assayed at weaning (W) and 2 wk later increased with age and was higher in 16-h fasted (day W + 15) than in 3-h fasted (day W + 17) pigs. Correlations were observed within litters in the fasting state, between the cortisol level and behavioral traits measured at day W + 23 (r = .70 for number of grunts, r = -.60 for exploration time). Dietary TRP did not affect the plasma cortisol level irrespective of the nutritional state after weaning. However, an interaction was noted between plasma cortisol and TRP status (P less than .05). Although dietary TRP induced large variations in brain amino acids and 5-hydroxyindole concentrations, changes in behavioral and cortisol responses were relatively minor.

["Eosinophilia-myalgia" syndrome due to L-tryptophan containing products. Cooperative evaluation of French Regional Centers of Pharmacovigilance. Analysis of 24 cases]

By November 17, 1989, the MMWR published the 154 first reports of a syndrome consisting of myalgia and eosinophilia (EMS), occurring with the consumption of L-tryptophan containing products (L-TrpCp) and which might represent a new clinical entity. To standardize reporting over the country, the CDC of Atlanta developed the following case definition: 1) a peripheral blood total eosinophil count of more than 1 x 10(9) cells per liter 2) generalized myalgia sufficiently severe to affect a patient's ability to pursue daily activities 3) the exclusion of infections or neoplastic conditions. The FDA then, announced its intention to seek a nationwide recall of all tryptophan containing products, followed by other european countries (UK, Germany, France). In France, a first decree (January 4th 1990) completed by a decree on May 11th confirms this decision for one year. This measure did not concern the medicinal products or some dietary supplements for newborn or young children. Since December 11th, 1989, 24 cases have been reported to the Regional Adverse Drug Reaction Monitoring Centres in France. These cases share the same features as the cases notified previously in the USA: overrepresentation of females, no relationship with the time and the daily intake, clinical similarities to the Shulman syndrome, and unknown prognosis. Now, more than one year after the onset of this illness, it seems that discontinuation of the ingestion of L-TrpCp can resolve or improve the symptoms in most cases, but sometimes the syndrome can persist. The causal relationship between the ingestion of L-TrpCp and this syndrome has been established. Whatever the mechanism for the development of EMS among tryptophan users remains unclear, as well as the role of eosinophilia and the factors for fibroblast proliferation. The epidemic emergence of this syndrome in July 89 raises the possibility of the contamination of tryptophan during the manufacturing process. To confirm this hypothesis, the same unusual peak in HPLC analysis was found both in case-associated L-Trp lots and in implicated-japanese manufacturer L-Trp lots in USA. But this would not explain the previous EMS reports before this contamination. Other hypotheses consist an inabnormality of tryptophan metabolism and/or an autoimmune process.

Impact of dietary tryptophan and behavioral type on growth performance and plasma amino acids of young pigs

Tryptophan (TRP) content in the protein of the weaning diet was varied from deficient (.70 g/16 g N) to adequate (1.15 g/16 g N) and excess (1.60 g/16 g N) in diets fed to 108 pigs from d 5 to d 26 after weaning (W) and in 72 pigs from d 26 after weaning to slaughter (100 kg live weight) to assess immediate and long-term effects of TRP on performance. Daily weight gain and feed efficiency were improved when dietary TRP was increased from deficient to adequate (+60 and +40%, respectively). Concurrently, daily feed intake was elevated moderately (+15%). No further improvement was observed with excess TRP. In the low TRP group, gain/feed was significantly poorer up to 25 kg live weight, but this effect did not continue later. Although no compensatory growth could be shown in the group fed the deficient diet, growth retardation was very small (1.5%; P greater than .10) at slaughter. Early changes in TRP supply did not affect either carcass or meat quality. Behavioral reactivity, as determined on day W + 5 in an "open-field" test, did not affect early performance, but growth rate during the growing-finishing stage (3.2%) or the whole period (2.5%) was greater by nonemotional than by emotional pigs. Plasma amino acid contents in blood samples, withdrawn on day W + 15 (fed state) and W + 17 (fasted state), were consistent with the effect of TRP on growth rates. However, in the fasted state, a diet x reactivity interaction suggested that TRP removal from the plasma was less rapid in nonemotional than in emotional pigs. Furthermore, increased plasma concentrations of essential amino acids and urea in the latter group suggested that protein and amino acid catabolism was more rapid in emotional than in nonemotional pigs. These data are discussed relative to the effect of the behavioral type of pig on its TRP requirement.

[Tryptophan-induced fasciitis-scleroderma-eosinophilia syndrome]

A fasciitis-sclerodermia-eosinophilia syndrome developed in four female patients, aged between 55 and 75 years, after the ingestion of tryptophan, 1.5-6.0 g daily, for 13 months to 7 years. It began characteristically with hard oedema of the limbs, sometimes also of the trunk. Later there occurred diffuse indurations of the body surface with fixation of the skin to fascial planes. This was associated with mainly sensory peripheral neuropathy. Three of the patients had an eosinophilia (12-30%). Histological examination revealed a cell-poor fasciitis, fibrosis of the cutis and subcutis, perimyositis and epidermal atrophy of varying degree. Erythrocyte sedimentation rate was at most slightly increased. Antinuclear antibodies were demonstrated in one patient (1:80). Serum aldolase concentration was raised (3.4-5.4 U/l), while creatine kinase was normal. The disease progressed even after tryptophan was discontinued, in only one patient there was improvement during glucocorticoid treatment. In two cases the skin induration regressed slowly after administration of methotrexate (15 mg weekly) and hydroxychloroquine (400 mg daily).

Research note: effect of excess lysine, methionine, threonine, or tryptophan on production performance of laying hens

An experiment was conducted with laying hens to determine effects of feeding excesses of several individual amino acids in a practical layer diet. Single Comb White Leghorn hens, which were in peak production (31 wk of age), were assigned to one of five dietary treatments: a 16% CP corn and soybean meal positive control diet, or this diet fortified with 1% additional L-Lys, 1% additional DL-Met, 1% additional L-Thr, or 1% additional L-Trp. The diets were fed for ad libitum intake for 4 consecutive wk of production. For the entire production period, hen-day egg production, egg yield, and feed intake were not significantly different among any of the treatments. The study indicated that considerable tolerance exists in high-producing laying hens for individual excesses of the amino acids commonly used as supplements in poultry diets.

Safety of L-tryptophan for pigs

Epidemic eosinophilia-myalgia syndrome (EMS) associated with excess L-tryptophan (Trp) consumption in humans has been declared a major public health problem. The EMS problem has not been observed in pigs, nor has comprehensive pathology associated with EMS in humans been described. Experiments were therefore conducted to evaluate the pathology and effects of excess dietary L-Trp for finishing (79 to 119 kg) pigs and to determine an LD50 of Trp for pigs. In Exp. 1, addition of .1 or 1% Trp to corn-soybean meal diets had no effect on growth performance or leukocyte and relative eosinophil counts or on plasma aspartate transferase, creatine phosphokinase, and lactate dehydrogenase activities. Likewise, untoward pathological effects of Trp feeding were not observed in the animals under study. In Exp. 2, supplementing the basal diet with 0, 2, and 4% Trp caused linear (P less than .05) decreases in weight gain, feed intake, and gain:feed ratio. Mortality could not be produced by acute oral dosing in the LD50 study (Exp. 3), wherein Trp doses between 2.00 and 5.71 g/kg of BW were administered by stomach tube. Vomiting occurred at oral doses greater than 5.71 g/kg of BW. These results suggest that oral ingestion of Trp in pigs is safe and that pigs can tolerate considerable excesses of Trp.

[Eosinophilia-myalgia syndrome]

The following is an outline of one typical case of chronic eosinophilia-myalgia syndrome (EMS). In 1987 a 62-year-old woman began taking L-tryptophan, 1.5 g nightly, due to sleeping difficulty. During the months preceding the appearance of EMS she continued to take L-tryptophan, derived from the biosynthetic production of the Japanese manufacturer "Showa Denko". She has suffered increasingly from severe myalgia and a proximal muscle weakness since July of 1989. In November, 1989 her white blood cell count measured 12.1 X 10(9)/l with 3.6 X 10(9) eosinophil cells/l. The bone marrow exhibited an increased granulopoesis and an extreme increase in the amount of eosinophil cells. The muscle biopsy specimen indicated an inflammation with perivascular distribution. The eosinophil cell count of the blood was quickly normalized via the introduction of prednisone over a short period. In the absence of further immunosuppressive therapy a slow improvement can be seen in the myalgia and in her general condition. Since the beginning of 1990 there has been a slow development of hyperpigmented scleroderma-like skin changes with distal distribution.

Excessive dietary tryptophan enhances plasma lipid peroxidation in rats

High plasma cholesterol levels and plasma lipid peroxidation are associated with atherosclerosis. The effect of excessive dietary tryptophan on plasma lipid peroxidation was studied in rats fed a diet containing soybean oil (control), as well as an atherogenic diet, containing coconut oil and cholesterol. Feeding the atherogenic diet resulted in a 5-fold increment in plasma cholesterol concentration with no significant effect of the tryptophan supplementation. The plasma obtained from the hypercholesterolemic rats exhibited a 67% increased lipid oxidation (measured as thiobarbituric acid reactive substances) in comparison to normocholesterolemic plasma. Dietary tryptophan supplementation increased plasma lipid peroxidation by 9 and 21% in the control and in the hypercholesterolemic animals, respectively. Similarly, the excessive dietary tryptophan enhanced macrophage cholesterol esterification rate by 40 and 38% following cell incubation with the plasma obtained from the control and from the hypercholesterolemic animals, respectively. Since tryptophan is the precursor of serotonin we have measured urine concentration of 5-hydroxyindoleacetic acid (5HIAA), the metabolite of serotonin, and found 22 and 118% elevation in 5HIAA in the tryptophan fed control and hypercholesterolemic rats, respectively. The direct effect of tryptophan and serotonin on in vitro lipid peroxidation was also studied. Low density lipoprotein (LDL) was peroxidized by incubation with copper ions in the presence of tryptophan or serotonin. Serotonin was shown to enhance LDL peroxidation whereas tryptophan had no effect on LDL peroxidation. We conclude that excessive dietary tryptophan may be atherogenic since it enhanced plasma lipid peroxidation in hypercholesterolemic rats and increased macrophage uptake of plasma cholesterol. These effects are probably associated with increased plasma concentration of serotonin following the consumption of a tryptophan supplemented diet.