Plasma taurine concentrations and M-mode echocardiographic measures in healthy cats and in cats with dilated cardiomyopathy.

M-mode echocardiography was completed and plasma taurine concentrations were determined in 79 healthy cats and 77 cats with dilated cardiomyopathy (DCM). In healthy cats, a relationship was not observed between plasma taurine concentrations and any M-mode echocardiographic measurement. End-systolic and end-diastolic cardiac chamber dimensions were larger; wall thickness measures were smaller; and calculations of fractional shortening were less in cats with DCM than in healthy cats. Plasma taurine concentrations less than 30 nmol/mL were detected in 7/79 healthy cats and in 52/77 cats with DCM. Of the 52 cats with DCM and an initial plasma taurine concentration less than 30 nmol/mL, 23 died or were euthanized during the first post-treatment week, 7 were lost to further study, and 22 improved after taurine supplementation. Of the 25 cats with DCM and an initial plasma taurine concentration greater than or equal to 30 nmol/mL, 9 died or were euthanatized during the first post-treatment week, and 9 were lost to further study. Two cats did not improve, of which one died and one was euthanatized 4 to 8 weeks after initiation of taurine supplementation. Five cats with a plasma taurine concentration greater than or equal to 30 nmol/mL improved after taurine supplementation. Myocardial function subsequently deteriorated in three of these cats. Two of the three cats had signs of congestive heart failure redevelop.

Transmethylation of homocysteine to methionine: efficiency in the rat and chick.

Experiments were conducted with young chicks and rats to quantify the efficacy of L-homocysteine as a methionine precursor. Linear growth responses were obtained to both L-methionine and L-homocysteine when added to a methionine-deficient intact-protein diet containing a plethora of cystine. Slope-ratio multiple regression methodology indicated L-homocysteine to be 64.5% as efficacious as L-methionine in rats and 62.5% as efficacious in chicks. Plasma-free methionine also increased linearly as graded levels of either L-methionine or L-homocysteine were added to the diet of rats. At higher dosages of L-homocysteine, betaine, but not choline, showed some efficacy in enhancing the conversion of homocysteine to methionine. In the linear response surface of the growth curve, however, supplemental betaine was without effect on L-homocysteine bioefficacy, as was also the case for supplemental sarcosine and N5-methyltetrahydrofolic acid.

Antagonism of arginine by excess dietary lysine in the growing dog.

Experiments were conducted with growing English Pointer puppies to examine the effects of ingesting excess lysine. A purified crystalline amino acid basal diet containing 0.40% L-arginine (the arginine requirement for maximal weight gain) and 0.91% L-lysine was fed in all assays. All diets were kept isonitrogenous by the addition of diammonium citrate, and lysine was supplied as L-lysine acetate. Both weight gain and gain/feed were reduced in the presence of 4% excess dietary lysine. However, 1 and 2% excess supplemental lysine had no effect on performance. In a second experiment, a growth response to supplemental arginine was obtained in the presence, but not in the absence, of a growth-depressing level of lysine (4%). Therefore, lysine appeared to depress growth by antagonizing arginine. The mechanism of the lysine-arginine antagonism was examined in a third experiment. Classic signs of arginine deficiency: orotic aciduria, depressed urea formation, hyperammonemia, a reduction in weight gain, and emesis were observed in puppies consuming excess lysine but not in their pair-fed controls. Excess lysine ingestion neither inhibited nor induced liver arginase, but it did result in a generalized amino aciduria early in the experiment. In addition, lysine did not appear to affect arginine absorption. Therefore, the mechanism behind the lysine-arginine antagonism in the dog remains to be elucidated.

Reduction of liver copper concentration by the organic arsenical, 3-nitro-4-hydroxyphenylarsonic acid.

The interaction between 3-nitro-4-hydroxyphenylarsonic acid (roxarsone) and Cu was studied in a series of experiments with crossbred, broiler-type chicks. A fully fortified corn-soybean meal diet was fed in all assays. While roxarsone caused a marked reduction in liver Cu concentration, arsanilic acid (4-aminophenylarsonic acid), As2O3 and As2O5 were without effect. When structural analogs of roxarsone were studied, it was found that o-nitrophenol and 3-nitro-4-hydroxybenzoic acid also had no effect on liver Cu concentration in birds fed a high level of Cu. However, liver Co concentration was reduced by the addition of either o-nitrophenol or roxarsone to the diets of birds fed a high level of Co. It was concluded that arsenic per se had no effect on liver Cu accumulation or depletion, but that a chelate was probably formed between Cu or Co and the nitroso and hydroxyl groups of the ring portion of roxarsone. In addition to the reduction in liver Cu deposition, concentrations of Cu in the bile, brain, heart and pancreas of chicks were reduced by the addition of roxarsone to a high-Cu diet. Neither dietary nor intraperitoneally (ip) injected roxarsone had an effect on liver Cu concentration when Cu was injected ip. Therefore, both roxarsone and Cu had to be present in the diet for the liver Cu-lowering effect of roxarsone to be exerted. A further experiment was conducted with growing rats to determine the effect of roxarsone on Cu balance. Feeding roxarsone elevated Cu excretion in the urine but had no effect on Cu excretion in the feces.

Arsenic-sulfur amino acid interactions in the chick.

Experiments were conducted with growing crossbred chicks to determine the reasons why cysteine exacerbates roxarsone (3-nitro-4-hydroxyphenylarsonic acid) toxicity. A fortified corn-soybean meal diet that met or exceeded all nutrient requirements of the young chick was fed. While cysteine enhanced roxarsone toxicity, it had little effect on the toxicity of the inorganic arsenicals As2O3 and As2O5. The toxicity of another pentavalent organic arsenical, phenylarsonic acid, was also exacerbated by cysteine. In contrast, the growth-depression resulting from feeding the trivalent form of phenylarsonic acid, i.e., phenylarsine oxide, was not affected by dietary addition of cysteine. Supplementation of the diet with cystine, methionine or K2SO4 did not exacerbate roxarsone toxicity. Reduced glutathione (GSH), however, slightly increased the gain/feed depression resulting from feeding 300 mg roxarsone/kg diet. When injected ip 1) roxarsone and cysteine, or 2) roxarsone and ascorbic acid killed 100 or 60% of the birds, respectively, within 48 h postinjection. Few (6.7%) deaths resulted from ip injections of the same level of roxarsone alone. Therefore, the potentiation of toxicity requires pentavalent organic arsenicals and compounds that can act as reducing agents. We concluded that cysteine exacerbates roxarsone toxicity by reducing it to the more toxic trivalent state.

Effect of 3-nitro-4-hydroxyphenylarsonic acid on copper utilization by the pig, rat and chick.

Experiments were conducted to examine the effect of dietary roxarsone (3-nitro-4-hydroxyphenylarsonic acid) on Cu utilization by the pig, chick and rat. A fortified corn-soybean meal diet was fed in each experiment. Roxarsone dramatically reduced liver Cu concentration at all levels of supplemental Cu fed. The level of roxarsone commonly fed, 50 mg/kg diet, resulted in a two- to fourfold depression in liver Cu concentration in all species studied. The effects of roxarsone on weight gain were more perplexing. In the chick, the diets containing 100 and 250 mg Cu/kg depressed growth in the presence, but not in the absence, of 50 mg/kg dietary roxarsone. In contrast, at toxic levels of Cu, roxarsone had no effect on (500 or 750 mg Cu/kg diet) or slightly alleviated (1,000 mg Cu/kg diet) the growth-depressing effects of Cu. In the rat, a roxarsone level of 50 mg/kg diet exacerbated the growth-depressing effect of 1,000 mg Cu/kg diet. However, Cu had no effect on the growth depression that resulted from feeding a toxic level of roxarsone (250 mg/kg diet). The antagonizing effects of roxarsone and Cu on weight gain were not evident in the pig. Supplemental Cu (250 mg/kg diet) improved weight gain, but not feed efficiency, in starter pigs. Roxarsone (50 mg/kg diet) had no effect on the growth-promoting effects of Cu.

Feed additive interactions in the chicken: reduction of tissue copper deposition by dietary roxarsone in healthy and in Eimeria acervulina-infected or Eimeria tenella-infected chicks.

Interactions among roxarsone, copper, and coccidiosis were studied in growing crossbred chicks. Corn-soy or corn-soy-corn gluten meal diets were fed in all assays. In the absence of supplemental copper, 50 mg/kg roxarsone did not affect gain. However, in the presence of 250 mg/kg supplemental copper, there was a depression in gain due to feeding 50 mg/kg roxarsone. In contrast, at a toxic level of copper (1000 mg/kg), a growth response resulted from feeding roxarsone. In all instances, roxarsone markedly decreased liver copper concentration in birds fed high levels of copper. Multiple crop intubations of Eimeria acervulina or Eimeria tenella depressed performance and exacerbated copper toxicity symptoms. Copper supplementation as well as coccidial infection resulted in depressed plasma pigmentation.

Urea cycle function in the dog with emphasis on the role of arginine.

English Pointer puppies were used in experiments designed to assess urea cycle function. A preliminary assay revealed a dietary arginine (Arg) requirement of 0.40% for maximal weight gain of puppies fed a chemically defined L-amino acid diet. Subsequent studies showed that consumption of an Arg-free diet resulted in growth failure, emetic episodes, mild hyperammonemia, decreased plasma Arg and urea, and orotic aciduria. Oral administration of ornithine (Orn), equimolar to 0.40% Arg, failed to correct these Arg deficiency symptoms. Consumption of an equimolar concentration of citrulline (Cit), on the other hand, resulted in near normal weight gains, but blood and urine metabolite levels still did not parallel those of dogs fed Arg. Plasma glucose concentration was unaffected by dietary treatment. Older dogs (20 weeks of age) performed no better than younger dogs (7 weeks of age) when fed an Arg-free diet. In a serial bleeding study, plasma ammonia increased after ingestion of an Arg-free diet, reached a peak during emesis and declined immediately thereafter. In contrast, plasma ammonia of dogs fed an Arg-adequate diet remained relatively constant. It was apparent that in terms of meaningful Arg replacement value, Orn had minimal activity. Cit could replace Arg for growth, but was not as efficient as Arg for urea cycle function.

Methionine peptides as potential food supplements: efficacy and susceptibility to Maillard browning.

Three experiments were conducted with young chicks fed purified diets to ascertain the bioefficacy of six different methionylmethionine (Met-Met) dipeptides, differing only in isomeric configuration, an oligopeptide (n = 8) of L-methionine, and also N-glycyl-L-methionine. DL/LD-Met-Met (50% D-Met-L-Met and 50% L-Met-D-Met), D-Met-L-Met, L-Met-D-Met, L-Met-L-Met, and N-Gly-L-Met were utilized as well as L-Met based on weight gain per millimole of sulfur consumed from each experimental compound. DD/LL-Met-Met (50% D-Met-D-Met and 50% L-Met-L-Met), D-Met-D-Met and L-oligo-Met were utilized less efficiently for chick growth. When the Met compounds were pretreated to facilitate Maillard browning (incubated at 37.6 degrees with dextrose at pH 9.5), all Met sources (except N-acetyl-L-Met, which was used as a positive control) exhibited reduced efficacy relative to an equivalent dietary addition of unreacted L-Met. The Met-Met peptides which when unreacted had been equivalent in efficacy to L-Met were, however, superior to L-Met when each compound, including L-Met, had undergone browning. N-Gly-L-Met was very reactive when heat-treated with dextrose, producing an almost black color after the 14-day incubation period, and its efficacy after browning was reduced by an even greater extent than was the case for L-Met.

Precursor (amino acid): product (vitamin) interrelationship for growing chicks as illustrated by tryptophan-niacin and methionine-choline.

Experiments were conducted with crossbred chicks to examine the growth response to a vitamin when its precursor amino acid was in either deficient or adequate supply in the diet and vice versa. The tryptophan-niacin and methionine-choline interrelationships were thus examined. No growth responses to dietary niacin or choline were observed during severe tryptophan or methionine deficiency, respectively. However, when adequate levels of the precursor amino acids were present, marked gain and gain/feed responses to these vitamins occurred. In contrast, gain and feed efficiency responses to tryptophan or methionine occurred regardless of the chick's niacin or choline status, respectively.

The choline-methionine interrelationship for growth of the chick.

Three experiments involving 1230 battery-reared crossbred chicks were conducted to evaluate the potential sparing effect of choline on methionine and vice versa. Experiment 1 employed a crystalline amino acid diet to establish the sulfur-amino acid (SAA) and choline requirement for maximal feed efficiency of chicks during the period 8 to 18 days posthatching. Six graded levels of DL-methionine (.20 to .45% in the presence of .20% L-cystine) and five of choline (0 to 1216 mg/kg) were employed in a 6 X 5 factorial treatment arrangement. Gain/feed ratio was maximized at 608 mg/kg choline at all levels of methionine and at .30 to .35% methionine at all levels of choline. Two identical experiments (8 to 25 days posthatching) with a corn-soybean meal diet were carried out to explore the relationship between supplemental methionine (0 to .20% in five equal increments) and supplemental choline (0, 217, and 434 mg/kg). Optimal performance occurred at .10% supplemental methionine regardless of choline level and at 217 mg/kg choline at supplemental methionine levels of 0 and .05%. At .10, .15, and .20% supplemental methionine, no gain or gain/feed response to supplemental choline was observed. It was thus apparent that excess levels of choline had minimal capacity to reduce the dietary requirement for methionine. Excess levels of methionine, however, seemed to have a consistent, although small, effect on the chick's dietary need for choline.

Utilization of D- and L-tryptophan by the growing dog.

Two 4 x 4 Latin square experiments were conducted with English Pointer puppies to determine the growth promoting capacity of D-tryptophan (trp) relative to L-trp and to estimate the trp requirement of the growing dog. Based upon a multiple linear regression slope-ratio technique, D-trp had an efficacy value of 35.5 +/- 6.4% relative to L-trp. The urine of dogs fed D-trp contained 14.6% of the ingested trp; no measurable trp was recovered in the urine of dogs fed L-trp. The trp requirement for maximal weight gain was at least .16% for 6-to 10-wk-old dogs, between .12 and .16% for 10- to 12-wk-old dogs and less than or equal to .12% for 12- to 14-wk-old dogs. The overall requirement for the 6- to 14-wk age period was .15%. Total N, as well as urea-N, in urine decreased and N retention increased with increasing levels of dietary L-trp; NH3-N, creatinine-N and fecal-N were unaffected by treatment.

Tolerance of the chick to excess dietary cadmium as influenced by dietary cysteine and by experimental infection with Eimeria acervulina.

Three experiments were conducted with 9-d-old crossbred chicks to determine the effect of supplemental L-cysteine.HCl.H2O on tolerance to excess dietary Cd. Cd levels of 30 or 60 mg/kg added to a fully fortified corn-soybean meal diet depressed both body weight gain and gain:feed ratio and increased kidney Cd concentration. Supplemental cysteine (i.e., .59% L-cysteine.HCl.H2O) did not alleviate the depression of weight gain or gain:feed ratio due to Cd feeding but did decrease kidney Cd accumulation. Eimeria acervulina infection (i.e., duodenal coccidiosis) depressed rate and efficiency of weight gain and resulted in increased Cd concentrations in kidney tissue. Cystein supplementation increased kidney cadmium concentration even further in E. acervulina-infected birds.

Roxarsone toxicity in the chick as influenced by dietary cysteine and copper and by experimental infection with Eimeria acervulina.

A series of experiments was conducted with crossbred chicks to determine the effects of L-cysteine, copper, and coccidiosis on roxarsone toxicity. Levels of roxarsone in excess of 50 mg/kg depressed performance and increased kidney arsenic concentration. L-cysteine x HCl x H2O (59%) increased rate and efficiency of gain when added to the basal diet, but depressed performance, increased kidney arsenic concentration, and enhanced mortality when added to diets containing toxic levels of roxarsone (200 mg/kg or higher). Moreover, excess copper (500 mg/kg) partially alleviated the gain/feed depression due to the combination of cysteine and roxarsone. Cysteine, in fact, increased feed efficiency in birds fed excess copper in the absence of roxarsone. Eimeria acervulina infection (duodenal coccidiosis) depressed gain and feed efficiency. The depression in feed efficiency was more severe in the presence of roxarsone (50 or 300 mg/kg). In the absence of coccidiosis, 50 mg/kg roxarsone slightly increased gain/feed ratio.

[Antigenicity of the human trophoblast]. / Untersuchungen über die Antigenität des menschlichen Trophoblasten.

In this a rabbit immunological serum against human trophoblast was obtained after triple intramuscular superficial villi extract injection from chorion of 6--7 week pregnancy with Freund's adjuvant. In immunofluorescent indirect reaction to this serum made on chorion and placenta sections some most intense specific fluorescence was obtained in cytoplasm of primordial cyto- and synytiotrophoblast. Some favourable influence of antigenic differences between ovum and mother especially implantation has been suggested.