The effect of dietary protein on the excretion of alpha2u, the sex-dependent protein of the adult male rat.

Adult male rats were maintained on normal (20% casein), protein-free (0% casein), high protein (50% casein), decicient protein (20% zein), and a supplemented, deficient protein (20% zein plus L-lysine and L-tryptophan) diets. Rats on a protein-free diet excreted approximately 1 mg alpha2u/24 h compared with a normal of 10-15 mg/24 h. Depleted rats placed on a 20% casein diet showed a rapid restoration of the normal alpha2u excretion as well as total urinary proteins. Accumulation of alpha2u in the blood serum was measured in nep-rectomized rats. Rats on a 0% casein diet accumulated only 30% of the alpha2u compared to normals. On a 50% casein diet, rats excreted 30-50 mg alpha2u/24 h. However, the accumulation was normal in the serum of nephrectomized rats. A high protein diet did not stimulate alpha2u synthesis but probably increased the renal loss of all urinary proteins. The excretion of alpha2u on a zein diet was reduced to the same degree as with the protein-free diet. Supplementation with lysine and tryptophan restored the capacity to eliminate alpha21 to near normal levels. Accumulation of alpha2u in the serum of nephrectomized rats kept on the zein diets showed that the effect to suppress the synthesis of the ahpha2u. Supplementation restored the biosynthesis of alpha2u. We conclude that the effect of dietary protein on the excretion of urinary proteins in the adult male rat is caused in large part by an influence on the hepatic biosynthesis of alphay2u. The biosynthesis of this protein, which represents approximately 30% of the total urinary proteins, is dependent on an adequate supply of dietary protein.

Inhibition of synaptosomal uptake of amino acid transmitters by diamines.

Reports of the inhibitory effects of diaminocarboxylic acids on the uptake of amino acid transmitters led the present authors to examine the effects of simple aliphatic diamines on the synaptosomal uptake of glutamate, aspartate, GABA and glycine. The diamines studied were the series from ethylenediamine through to 1,7-diaminoheptane; DL-2,4-diaminobutyric acid (DABA) was also tested for comparative purposes. The greatest inhibition seen was on the uptake of glycine and GABA. Weaker effects on uptake were seen with glutamate, while aspartate was unaffected. The patterns of inhibition for glycine and GABA were similar and the effects were dose-dependent. 1,2-Diaminopropane was the most inhibitory, followed by ethylenediamine and 1,7-diaminoheptane. The reported inhibitory effects of DL-2,4-diaminobutyric acid on the uptake of GABA and glutamate were confirmed; comparable inhibition of the uptake of glycine and aspartate was seen but the effects on GABA were most potent. Inhibition of the uptake of GABA by 1,2-diaminopropane was approximately one fifteenth that reported for DL-2,4-diaminobutyric acid. The inhibition by diamine of the uptake of glycine and GABA can provide an explanation of the depressant effects of diamines, seen after ventricular administration; however, the excitotoxic effects of the diamines 1,3-diaminopropane through to 1,7-diaminoheptane could not be explained by the present results.

A toxicological investigation of the garden shrub Brunfelsia calcyina var. floribunda (yesterday-today-and-tomorrow) in three species.

Brunfelsia calcyina var. floribunda is an ornamental evergreen shrub found in the United States. A diagnosis of the fatal intoxication of a canine due to consumption of plant material (primarily berries) was made. The significant features of the clinical constellation were similar to those seen with substances interfering with the neurotransmission process, such as lathyrus or strychnine. Necropsy findings on the canine were unrevealing. Toxicologic studies performed on mice and rats with ground shrub material demonstrated that all parts of this plant are toxic, but unequally so. All plant preparations produced signs similar to those of a spinal convulsant. There were no distinguishing gross pathologic or histopathologic findings associated with the toxicoses induced in the laboratory animals with preparations from this plant. The toxic principles from this shrub are water soluble and very stable. The ability of aqueous extracts stored at 4 C to produce the clinical syndrome and subsequent lethality remained unchanged over a period of 4 months. Exposures are not always fatal. They most often occur in the canine and there is a significant hazard for small children.

The toxicologic investigation of a feed grain contaminated with seeds of the plant species Cassia.

Feed grain suspected of causing death in a group of pigs was evaluated for toxic potential in chickens. The contaminated grain sorghum mixture was examined visually and contained 3.7% Cassia occidentalis and 1.6% Cassia obtusifolia seeds by weight. Thirty-two chicks were fed a sample of this suspect grain sorghum mixture. Chickens receiving the contaminated grain lost weight rapidly, exhibited clinical signs typical of intoxication with Cassia spp., and by day 16 were severely debilitated. Necropsy and histologic and electron microscopic examinations demonstrated a skeletal and cardiac degenerative myopathy consistent with intoxication by Cassia occidentalis. These toxicologic investigations verified the toxic potential of the contaminated sorghum mixture for chickens, and these comparative observations support prior diagnostic efforts implicating Cassia spp. as a cause of illness in swine.

Determination of the oral toxicity of Sesbania drummondii seeds in chickens.

Extracts of Sesbania drummondii administered to chickens by oral intubation are lethal within several days. Effects are dose-dependent; a dose of 1% of body weight is uniformly lethal in 5 days. Signs of poisoning include weakness, depression (CNS), anorexia, diarrhea, ruffled feathers, cold feet, and rapid loss of body weight. Microscopic examination indicates damage to kidney glomeruli and leakage of protein into the kidney tubules. Packed cell volume and plasma glucose concentrations show no difference between controls and treated chickens; however, creatine kinase is increased and plasma cholinesterase and total plasma protein values are severely depressed in poisoned birds. Neither a specific toxin nor a mechanism of action for toxicity has yet been identified.

Effects of prednisolone on glucose tolerance and insulin secretion in the dog.

Effects of prednisolone on glucose tolerance and insulin secretion were evaluated in healthy dogs. Dogs were given 1 mg of prednisolone/kg of body weight/day (n = 5) or 2 mg of prednisolone/kg/day (n = 6) orally for 3 weeks. Intravenous glucose tolerance tests (600 mg/kg) were administered before and after treatment to evaluate plasma glucose in fasting dogs, glucose fractional clearance rate, serum insulin in fasting dogs, insulin peak response, total insulin secretion, and insulinogenic index. A significant difference (P less than 0.05) in plasma glucose in fasting dogs was observed for the 2 mg/kg dose, although values were still within the reference range. There was no significant effect on glucose fractional clearance rate (glucose tolerance) or insulin secretion. Seemingly, peripheral insulin resistance resulting in hyperinsulinemia or decreased glucose tolerance could not be identified in association with 1 or 2 mg of prednisolone/kg/day for 3 weeks in healthy dogs.

Toxic Bermuda grass tremor in the goat: an electroencephalographic study.

Tremorgenic Bermuda grass hay harvested during the 1971 Louisiana outbreak of toxicosis and kept in cold storage until 1979 was fed to a female Nubian cross goat. Cortical EEG from chronically implanted screw electrodes was recorded daily during hay consumption. Typical clinical signs of toxicosis were manifested as ataxia on day 8 and tremor on day 11. Motor activity returned to normal 2 days after reinstitution of nontoxic Bermuda grass hay. Changes in EEG amplitudes, frequency content, or wave-forms were not seen during the development or after the appearance of toxicosis. The administration of diazepam at the height of toxicosis suppressed the tremor for several hours.

Comparison of the effects of Sesbania drummondii on the hepatic microsomal monooxygenase systems of chickens and rats.

Sesbania drummondii, a toxic leguminous shrub found throughout the southeastern United States, induces different responses in chicken vs rat hepatic microsomal monooxygenase systems. Groups of 4- to 8-week-old Sprague-Dawley rats and White Leghorn chickens were given extracts of S drummondii by gavage for 3 days. Doses, which were 0.4 and 0.8% of daily body weights, respectively, for the rats and chickens, were adjusted to induce similar clinical lesions in the 2 species. The hepatic microsomal monooxygenase systems of control and treated animals were compared, using cytochrome P-450 content, cytochrome b5 content, NADH- and NADPH-cytochrome c-reductase activity, and 6 cytochrome P-450 mediated enzyme activities. Increases of twofold in the cytochrome P-450 content, NADPH-cytochrome c-reductase, aminopyrine-N-demethylase, aniline hydroxylase, ethoxycoumarin-O-deethylase, and aryl hydrocarbon hydroxylase activities; fourfold in the aldrin epoxidase activity; and 15-fold in the ethoxyresorufin-O-deethylase activity were observed in the S drummondii-treated chickens. In contrast, the treated rats had nearly twofold decreases in these values, suggesting a species-specific effect of S drummondii on microsomal monooxygenase systems, ie, induced with S drummondii.

Effects of a Cassia occidentalis extract in the domestic chicken (Gallus domesticus).

The effects of an orally administered Cassia occidentalis extract were studied in chickens. A 25 mM sodium bicarbonate solution effectively extracted the toxic principle. Toxic activity was reduced, but not eliminated, when the heated extract (90 C, 40 minutes) was administered. The toxic principle was in the pellet after centrifuging the extract at 38,000 X g. Daily administration of the extract produced weight loss and muscular weakness. Microscopic examination revealed skeletal and cardiac muscle degeneration and hepatocyte vacuolation. Electron microscopic examination revealed mitochondrial disruption. Respiratory studies on liver mitochondria isolated from treated chickens demonstrated lower phosphorylation ratios, lower respiratory control ratios, and lower rates of oxygen use.

Preliminary isolation of a myodegenerative toxic principle from Cassia occidentalis.

Aqueous and organic extractions of ground seeds of Cassia occidentalis were obtained. Chickens were dosed with extracted material to assess the toxicity of the extracts. Organic extracts with methanol, ethanol, chloroform, ethyl acetate, and benzene were ineffective in removing the toxin from the seeds. Aqueous extractions, using 25 mM sodium bicarbonate or 250 mM sodium citrate, removed the toxin from the seeds, but left the toxin bound to particulate matter in the extract. Addition of Triton X-100 to the aqueous buffers effectively solubilized the toxin from the particulate matter. Signs of intoxication in the chickens were loss of weight, weakness, diarrhea, hypothermia, occasionally ataxia, and recumbency; then death. Gross lesions included paleness of skeletal and cardiac muscles and congestion of the liver. Microscopic lesions in muscle tissue were vacuolation, proliferation of sarcolemmal nuclei, and separation of myofibrils. Electron microscopic examination revealed disruption of mitochondrial cristae and swelling and rupture of mitochondria.

Smooth muscle inhibition by an extract of Sesbania drummondii.

The acute effects of an extract of Sesbania drummondii were assessed in vitro on the smooth muscle contractility of intestine and lung parenchyma in the chicken and aortic arch in the rat. Dose-response contraction curves for histamine, carbachol, and norepinephrine were obtained in the ileal, parenchymal, and aortic strips, respectively. After washing was completed, the strips returned to baseline tensions and then were incubated for 10 minutes with an ethyl acetate extraction fraction of S drummondii (molecular weight less than 500). Dose-response curves to the same agonists were repeated at the end of the incubation period. Contractile responsiveness of chicken ileum was little affected by acute incubation of the tissue with the extract. Comparison with the great inhibition of in vitro ileal contractility seen previously in chickens with chronic toxicosis indicated that intestinal inhibition was not due to acute effects of sesbania, but required time for a toxic metabolite to be formed or for damage to occur from affected vasculature. Contractile responsiveness of chicken lung parenchyma to histamine (10(-5) M and 10(-4) M) was significantly decreased, as was rat aortic responsiveness to norepinephrine (10(-7) M to 10(-4) M). Responses in parenchyma were not as greatly inhibited as those in tissue from animals with chronic toxicosis. Greatest inhibition of contractility was seen in the vascular strips, indicating that vascular inhibition has a role in pathologic changes. To test the vasculature inhibition effect in vivo, anesthetized, catheterized rats were given 100-microliter aliquots of dilutions of the extract, IV.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of smooth muscle function in Sesbania drummondii toxicosis in Gallus domesticus.

An in vitro assessment based on tissue responsiveness to 2 agonists-histamine and carbachol-was made on smooth muscle activity in chickens experimentally poisoned with sesbania. Crude extracts of Sesbania drummondii were prepared and 2 dosage levels, 0.25% and 0.5% of body weight, were used. The birds were dosed orally with the extract for 3 consecutive days, and on the 4th day segments of ileum and lung were collected from each bird. The isometric contractions of each tissue, produced by the addition of histamine or carbachol in graded concentrations, were recorded. The cumulative concentration-effect curves for the tissues to the agonists were constructed and compared with respective control curves. The results indicated the responsiveness of the tissues in the treated groups was significantly decreased, compared with that of tissues in the controls. Responses of both intestinal and parenchymal strips in the chickens given the higher dosage (0.5%) were decreased significantly, whereas in those given the smaller dosage (0.25%), only parenchyma had a significant response. This indicates that the activity of smooth muscles in general was depressed by sesbania. The effect was more evident in the lung than in the intestine. Therefore, an active principle in the extract which affects smooth muscle, rather than causing direct irritation, may exist. This assessment of smooth muscle activity is sensitive and was effective in detecting changes in tissues from sesbania-treated birds which had not shown any clinical signs. The results also support the possibility that smooth muscle involvement could be a primary cause of toxicity in sesbania poisoning.

Contribution of whole blood L-lactate, pyruvate, D-lactate, acetoacetate, and 3-hydroxybutyrate concentrations to the plasma anion gap in horses with intestinal disorders.

Increased anion gap (AG) was due, in part, to L-lactic acidosis in 14 of 14 horses with intestinal disorders. In a few horses, increased whole blood concentrations of D-lactate made a minor contribution to the AG. However, the increase in AG was often greater than the sum of the increases in these 2 acid anions. This unexplained increase was not a result of increases in whole blood pyruvate, 3-hydroxybutyrate, or acetoacetate concentrations or serum albumin or phosphate concentrations. Identification of other anions causing increased AG could lead to better understanding, diagnosis, and treatment of metabolic imbalances in critically ill horses.

Growth and 24 hour eating patterns of rats kept under various light:dark conditions.

Up to 84 days there was no difference in growth between groups of rats kept from birth at 8:16, 12:12 or 18:6 hours light:dark. More eating activity takes place during the light period when this is a larger part of the 24 hour day.