The topical effects of Wy-41,195 [2-cyano-3-(methylamino)phenylamino] oxoacetic acid, sodium salt and disodium cromoglycate in the rat passive eyelid anaphylaxis

Wy-41,195 demonstrated significant inhibitory effects (54-60%) when administered topically at 0.25-2% concentrations in a rat passive eyelid anaphylaxis assay. In contrast, topically applied disodium cromoglycate (DSCG) showed non significant inhibition at these concentrations. The potency of Wy-41,195 was more than 8 times greater than DSCG, and this compound may be an effective topical agent in man in preventing allergic and associated conditions.

Comparison of inflammatory changes in established type II collagen- and adjuvant-induced arthritis using outbred Wistar rats

Type II collagen- and adjuvant-induced arthritis in outbred Wistar rats were compared using parameters that measured the inflammatory response, cellular and humoral immunity, blood protein changes, drug metabolism and histopathological and bony changes of the inflamed paws. There was a lesser incidence (40-70%) and severity of collagen disease than the adjuvant model (incidence approximately 100%). The use of MDP increased the incidence and severity of collagen arthritis. The acute phase protein response (plasma fibrinogen) was similar in both models during the peak of inflammatory response. Drug metabolism was inhibited in both type II collagen boosted with MDP or M. butyricum sensitized rats with arthritis; however, arthritic rats sensitized with collagen alone produced no inhibition. Only collagen arthritic rats produced type II collagen antibody and exhibited delayed hypersensitivity to type II collagen. Bony changes as assessed by radiographic evaluation were more severe in adjuvant arthritic rats than in the collagen arthritic model; histopathological findings from these animals confirmed this observation. The primary lesions in both models were periosteal reaction of the bone and ankylosis. Several classes of antiarthritic drugs were compared in both models using paw edema measurements and bony changes by radiographic evaluation. Drugs with inhibitory activity in both models were indomethacin, methylprednisolone, D-penicillamine and gold sodium thiomalate. Levamisole, chloroquine and auranofin were inactive in both models.

Immunomodulatory activity of Wy-18,251 (3-(p-chlorophenyl)thiazolo[3,2-a]benzimidazole-2-acetic acid)

The in vitro and in vivo effects of the experimental immunomodulatory agent Wy-18,251 (3-(p-chlorophenyl)thiazolo[3,2-a]benzimidazole-2-acetic acid) were studied in comparison with levamisole and indomethacin. Levamisole (4 mg/kg, i.v.) but not Wy-18,251 (less than or equal to 10 mg/kg, i.v.) enhanced carbon clearance rates in vivo in mice. Both Wy-18,251 and levamisole (100 mg/kg, p.o.) significantly suppressed the symptoms of experimental allergic encephalomyelitis (EAE) in rats injected with spinal cord emulsion, but neither were as effective as tilorone in this model. Wy-18,251 and levamisole (1-100 mg/kg, p.o.) suppressed the in vivo generation of plaque-forming cells (PFC) in mice immunized with sheep red blood cells while indomethacin (9 mg/kg, p.o.) enhanced PFC formation. All 3 agents (10(-5) - 10(-6) M) enhanced the in vitro ovalbumin (OA)-specific and Con A- or PHA-induced proliferative response and Con A-stimulated interleukin 2 (IL-2) synthesis of rat spleen cells. Furthermore, in vivo treatment of rats with 1-10 mg/kg (p.o.) of Wy-18,251 and levamisole but not indomethacin increased the subsequent in vitro mitogen or antigen (OA) responsiveness of spleen cells. None of the drugs (10(-5) - 10(-7) M) influenced the natural killer cell (NK) activity of rat spleen cells when incorporated directly into the 51Cr release NK assay.

Effect of source of dietary energy and energy restriction during lactation on sow and litter performance

The effects of source of energy and energy restriction during lactation on sow and litter performance were investigated in an experiment with 90 primiparous sows. At parturition, the sows were randomly assigned to diets containing either tallow or cornstarch as a major energy source. Energy intake was restricted to 8 Mcal of metabolizable energy X sow-1 X d-1 during a 28-d lactation. All sows received equal amounts of crude protein, vitamins and minerals daily, which met or exceeded standard recommendations. Sows fed the diet with tallow lost more weight (P less than .05) during lactation than those fed the diet with cornstarch. Litter size at d 28 was greater (P less than .07) for sows fed cornstarch than for sows fed tallow. However, pig and litter weights on d 14 and 28 of lactation were similar between dietary treatments. Sows were bled on d 110 of gestation and d 14 and 28 of lactation and blood plasma was analyzed for urea. A significant treatment X time interaction was found for plasma urea. Sows fed the diet with tallow appeared to catabolize more protein than those fed the diet with cornstarch. Energy digestibility was lower (P less than .01) in the diet containing tallow, but protein digestibility was not affected by source of energy. Percentages of sows in estrus by 7, 14 and 70 d post-weaning were not different between treatments.

Lymphoid abnormalities in rats with adjuvant-induced arthritis. I. Mitogen responsiveness and lymphokine synthesis

Lewis rats injected in the hind paw with Mycobacterium butyricum develop a severe polyarthritis which shares certain features in common with rheumatoid arthritis in man. Spleen and peripheral blood mononuclear cells from rats with this form of arthritic disease proliferate poorly in vitro in response to concanavalin A (con A), phytohaemagglutinin (PHA), and pokeweed mitogen (PWM). The splenic hyporesponsiveness appears within four days of M. butyricum injection (three to five days prior to the development of detectable arthritis), reaches a peak 16-22 days following injection, and persists for at least 40 days. Buffalo strain rats injected with M. butyricum do not develop arthritis, and their spleen cells respond normally to con A, PHA, and PWM. In response to lipopolysaccharide (LPS) the synthesis of interleukin 1 (IL-1) by spleen or peritoneal macrophages from arthritic Lewis rats equalled or exceeded that of macrophages from normal rats. In contrast splenic T cells from arthritic rats produced reduced amounts of interleukin 2 (IL-2; T cell growth factor) in response to stimulation with PHA or con A. Moreover, con-A-activated spleen cells from arthritic rats failed to bind IL-2 and to respond to this growth factor with increased 3H-TdR uptake as did normal spleen cells. In-vitro treatment of 'arthritic' cells with 10(-5) M indomethacin did not restore to normal their reduced mitogen responsiveness, and spleen cells from normal and arthritic rats were equally sensitive to the inhibitory effects of prostaglandin E2 on con-A-induced proliferative responses. These results indicate that peripheral lymphoid function is compromised in rats with adjuvant-induced arthritis and that this functional deficit is mediated by aberrant synthesis of and response to IL-2 by T cells of arthritic animals.

The effects of antiallergic and bronchodilator drugs on platelet-activating factor (PAF-acether) induced bronchospasm and platelet aggregation

Platelet activating factor (PAF-acether) is a potential mediator of asthma and inflammation. Recently, the suggestion was made that inhibition of PAF-acether by disodium cromoglycate (DSCG) might be partly responsible for the effectiveness of DSCG in asthma. We have extended these studies and examined the effects of antiallergic and bronchodilator drugs on PAF-acether induced bronchospasm after i.v. administration in guinea pigs and in vitro platelet aggregation in rabbits. Neither DSCG nor Wy-41,195, a potent orally effective antiallergic, altered either of the PAF-acether responses. Furthermore, aerosolized ipratropium, promethazine, ketotifen and FPL 55712 failed to affect the PAF-acether-induced bronchospasm. The same drugs were also ineffective against platelet aggregation induced by PAF-acether. In contrast, aerosolized thiazinamium chloride inhibited the bronchospasm and also inhibited PAF-acether-induced platelet aggregation. Thiazinamium chloride possessed weak antiaggregatory effects against ADP and was without effect against arachidonic acid-induced platelet aggregation. Both lipoxygenase and cyclooxygenase products of arachidonic acid metabolism appear to be involved in PAF-acether bronchospasm since i.v. administered lipoxygenase inhibitors (phenidone, BW755c and NDGA) and indomethacin independently inhibited this in vivo response. However, these drugs failed to alter platelet aggregation to PAF-acether. Thiazinamium chloride may be capable of directly antagonizing the PAF-acether-induced platelet aggregatory response and, in addition, inhibiting the synthesis and/or effects of bronchoconstrictor amines and endogenously generated arachidonic acid metabolites.

Neurologic complications associated with gold therapy for rheumatoid arthritis

Neurologic complications of gold are rare and include peripheral neuropathy, a Guillain-Barré-type syndrome, cranial nerve palsies and encephalopathy. Three cases of cranial neuropathy complicating chrysotherapy for rheumatoid arthritis are described. One also had a sensorimotor neuropathy associated with segmental demyelination and axonal degeneration, and another developed an encephalopathy which, on contrast enhanced computed tomographic scanning, showed reversible cerebral and cerebellar white matter lesions. Early recognition and prompt withdrawal of chrysotherapy are the mainstay of management of this lesser known complication.

A comparative study of the antiinflammatory activity of fentiazac and its major metabolite, p-hydroxy fentiazac

Wy-25,110, the p-OH metabolite of fentiazac was approximately 100 times less potent than fentiazac after oral administration in rat carrageenan edema and 100-130 times less potent as an inhibitor of prostaglandin synthesis by mouse peritoneal macrophages. In addition, Wy-25,110 was one twelfth as active as fentiazac against immunologic-induced inflammation on day 16 in rat adjuvant arthritis. Wy-25,110 was also much less potent than fentiazac when administered intravenously, suggesting that inadequate oral absorption does not account for its lack of potency. Thus it seems unlikely that the p-OH metabolite contributes greatly to the antiinflammatory properties of fentiazac.

Effect of forskolin on prostaglandin synthesis by mouse resident peritoneal macrophages

The relationship between cyclic 3',5'-adenosine monophosphate (cAMP) and prostaglandin (PG) synthesis was investigated in the mouse resident peritoneal macrophage. Macrophages were established as monolayer cultures in petri dishes. After addition of various agents, culture media and cells were removed for PG and cAMP analysis by standard radiochromatographic techniques and radioimmunoassay respectively. Forskolin, a potent receptor-independent adenylate cyclase activator, rapidly increased cAMP synthesis within 5 min in a dose related fashion in both non-treated macrophages and macrophages treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). Furthermore, forskolin markedly reduced both 6-keto-PGF1 alpha and PGE2 synthesis induced by TPA and this inhibition was inversely correlated with increases with cAMP generation. In contrast, cholera toxin failed to mimic the inhibitory action of forskolin on PG synthesis even though it induced similar increases in cAMP; however this increase was only evident after a lag period of at least 1 h. Additionally, forskolin, but no cholera toxin inhibited PG synthesis and zymosan phagocytosis when these cells were activated with zymosan particles. These observations, therefore, suggest that a rise in cAMP is not always correlated with a reduction in PG synthesis.

Effect of acute spinal cord injury on axonal counts in the pyramidal tract of rats

The concentration of axons in the pyramidal tract of normal and spinal cord-injured rats was determined by counting axons in sections of spinal cord stained by the Holmes technique. In the normal rat the axon concentration was uniform in the cervical, thoracic, and lumbar regions, although the size of the tract diminished progressively with its descent in the cord. After acute cord transection or compression injury, the axon concentration distal to the injury site diminished markedly. However, an appreciable number of distal axons persisted after injury, due to either delayed degeneration or to the presence of an admixture of afferent fibers. The axonal counting technique developed in this study should be helpful in experiments on spinal cord injury and regeneration.

Bronchodilating activity of forskolin in vitro and in vivo

The effect of forskolin, a receptor-independent adenylate cyclase activator on acetylcholine (ACh)-, histamine- and leukotriene D4 (LTD4)-induced contractions in isolated tracheal spirals was investigated. Forskolin reduced the contraction due to these agonists (IC50S: ACh 5.8 X 10(-6) M; histamine 4 X 10(-7) M; LTD4 3.1 X 10(-6) M). Forskolin was also effective against ACh- and histamine-induced contraction when added during contraction. In ovalbumin-sensitized guinea pigs, intravenously and intraduodenally administered forskolin significantly reduced the bronchospasm due to aerosol administration of ovalbumin. These results suggest that forskolin could prove useful in delineating the role of cyclic nucleotides in pulmonary smooth muscle responses.

The absence of antibodies to type II collagen in established adjuvant arthritis in rats

Utilizing an adjuvant arthritis model in rats, we examined humoral immunity to collagen and inflammation in animals with active disease and during drug therapy. Humoral immunity to types I or II collagen was not detected in the sera of rats with advanced adjuvant arthritis; this was in marked contrast to rats with type II collagen-induced arthritis which possessed serum antibodies to native and denatured type II collagen. Hind paw edema and bone pathology were monitored as parameters of inflammation. A new investigational drug, Wy-41,770, was most effective in reducing all of these aspects of inflammatory disease while indomethacin, methylprednisolone, and D-penicillamine caused a less significant diminution of only some of these parameters of inflammation. Antibodies to collagen were not detected in the sera of rats treated with the drugs under study. These data demonstrate that adjuvant arthritis can occur in rats in the absence of antibodies to types I or II collagen.

Differential effects of putative lipoxygenase inhibitors on arachidonic acid metabolism in cell-free and intact cell preparations

The effects of nordihydroguairetic acid (NDGA), 3-amino-1-trifluoromethyl-)-phenyl-2-pyrazoline (BW755c), eicostatetraynoic acid (ETYA), phenidone, quercetin, and indomethacin (INDO) on the synthesis of 15-hydroxyeicosatatetraenoic acid (15-HETE) from soybean 15-lipoxygenase, leukotriene B4 (LTB4) from 5-lipoxygenase, and prostaglandin E2 (PGE2) from cyclooxygenase enzymes of rat neutrophils and mouse peritoneal macrophages were investigated. All of the drugs caused a dose-related inhibition of increased oxygen consumption by soybean 15-lipoxygenase in the presence of arachidonic acid and the rank order of potency was phenidone greater than or equal to BW755c greater than ETYA greater than quercetin greater than NDGA greater than indomethacin. The reduction in oxygen consumption correlated with a reduction of 15-HETE formation as identified by high-performance liquid chromatography. Apart from indomethacin, these drugs were also effective against the rat neutrophil 5-lipoxygenase, although the rank order of potency did not correlate with that obtained with soybean 15-lipoxygenase. Furthermore, in both A23187-activated rat neutrophils and zymosan-activated mouse peritoneal macrophages the synthesis of prostaglandins was inhibited by all of these drugs. In the neutrophils, the rank order of potency was INDO greater than ETYA greater than BW755c greater than quercetin greater than NDGA greater than phenidone, whereas in mouse peritoneal macrophages, the order was INDO greater than ETYA greater than BW755c greater than NDGA greater than quercetin greater than phenidone. These results suggest that putative lipoxygenase inhibitors exhibit both qualitative and quantitative differences in their effects on both lipoxygenases and cyclooxygenases.

Effect of gold salts, D-penicillamine and benoxaprofen on type II collagen-induced arthritis in rats

We investigated the therapeutic effect of two gold salts, gold sodium thiomalate (GST, i.m.) and auranofin (p.o.), D-penicillamine (p.o.) and benoxaprofen (p.o.) in rat collagen-induced arthritis using type II collagen from fetal bovine articular cartilage. GST, but not auranofin, reduced hind paw edema and bone pathology. However, auranofin reduced serum copper and zymosan-induced prostaglandin production from peritoneal macrophages. In contrast, GST increased both serum copper and macrophage prostaglandin production by zymosan. Benoxaprofen reduced both hind paw edema and pathology, whereas D-penicillamine was without effect. None of these treatments influenced the circulating level of antibody to type II collagen.

The antiinflammatory profile of (5H-dibenzo[a,d]-cyclohepten-5-ylidene)acetic acid (WY-41,770), an agent possessing weak prostaglandin synthetase inhibitory activity that is devoid of gastric side effects

Wy-41,770 [(5H-dibenzo[a,d]cyclohepten-5-ylidene)acetic acid], a novel acrylic acid, was compared to indomethacin and aspirin in standard antiinflammatory, analgesic and antipyretic animal models. The acute antiinflammatory, analgesic and antipyretic activity of Wy-41,770 (oral ED50S 50-170 mg/kg) was similar to aspirin; however, it was considerably more potent orally in adjuvant arthritis in the rat (ED50, 16 mg/kg) and urate-induced synovitis in the dog (ED50, 4.5 mg/kg). Wy-41,770 was a weak inhibitor of prostaglandin biosynthesis and did not inhibit either 5- or 15-lipoxygenase. Furthermore, the cellular migration characteristic of carrageenan pleurisy was not affected by Wy-41,770. Unlike a majority of NSAIDs, it produced no gastric irritation in rats after either acute or chronic oral administration over the range 400-800 mg/kg. The major mechanism of action of Wy-41,770 has yet to be identified but does not seem to involve interference of arachidonic acid metabolism.

Serum chemical values of gestating and lactating swine: reference values

Reference values of 18 serum constituents were determined in gestating (n = 33) and lactating (n = 13) swine. Serum concentrations of calcium, glucose, urea nitrogen, cholesterol, total protein, and globulin were lower (P less than 0.10) during gestation than during lactation. Concentrations of creatinine, triglycerides, and creatine phosphokinase were higher (P less than 0.10) during gestation than during lactation. Creatinine concentration increased (P less than 0.05) from lactation days 14 to 26.

Early mortality following stroke: a prospective review

Analysis of early deaths after stroke is important, since some deaths may be preventable. Previous studies have relied on retrospective and often incomplete clinical data, for comparison with pathological findings. The present study is based on 1073 consecutive stroke patients admitted to an intensive care stroke unit from a well-defined population. There were 212 deaths within the first 30 days, yielding a mortality rate of 20%. Clinical, radiological, and laboratory data were collected prospectively according to a standardized protocol. Autopsies were performed on 90 of the 212 patients, and CT scanning on a further 27. Early mortality after stroke exhibits a bimodal distribution. One peak occurs during the first week, and a second during the second and third weeks. The majority of deaths in the first week are due to transtentorial herniation. Of these, deaths due to hemorrhage usually occur within the first three days, whilst deaths due to infarction peak between the third and sixth day post ictus. After the first week, deaths due to relative immobility (pneumonia, pulmonary embolism and sepsis) predominate, peaking towards the end of the second week. Cardiac deaths occur throughout the first month, and unfortunately account for many deaths in patients with small functional deficits.

Relationship of lactation energy intake and occurrence of postweaning estrus to body and backfat composition in sows

Forty-five crossbred primiparous sows were used to determine the relationship of lactation energy intake and the occurrence of postweaning estrus to (1) body fat (percentage), (2) lean body mass (LBM) and (3) qualitative and quantitative characteristics of adipose tissue. Sows received 8 (Lo) or 16 (Hi) Mcal of metabolizable energy (ME)/d during lactation and 5.4 Mcal of ME/d postweaning. Serum samples were obtained 1 d before weaning (d 0) and analyzed for creatinine and urea-N (indices of muscle and amino acid catabolism, respectively). Subcutaneous adipose tissue samples were obtained and analyzed for total lipid and myristic, palmitic, palmitoleic, stearic, oleic and linoleic acids. Last rib backfat thickness determined at weaning was used to estimate body fat (percentage). Lean body mass was estimated from 48-h creatinine excretion rates determined on d 15 and 16 postweaning. Sows fed the Lo diet that returned (Lo-R) and did not return (Lo-NR) to estrus by d 14 postweaning lost more (P less than .01) weight during lactation, gained more (P less than .01) weight postweaning, had higher (P less than .07) body fat (percentage) and a slight trend toward lower creatinine excretion rate than sows fed the Hi diet that returned to estrus (Hi-R). Adipose tissue from sows in the Lo-R and Lo-NR groups had less (P less than .05) lipid than that from sows in the Hi-R group. Concentrations of oleic and stearic acids were lower and higher (P less than .01), respectively, in adipose tissue from sows in the Lo-R and Lo-NR vs Hi-R groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Rebound nystagmus in olivocerebellar atrophy: a clinicopathological correlation

Rebound nystagmus was recorded in a patient with cerebellar dysfunction. Neuropathological examination showed degeneration of the inferior olivary nuclei and the cerebellar cortex. The basis pontis and the brainstem tegmentum were spared. Rebound nystagmus is attributed to a smooth eye movement bias that is generated within intact vestibuloocular pathways to oppose gaze-evoked centripetal drift of the eyes. The source of the rebound bias was not visual, because rebound nystagmus normally occurs in darkness, smooth pursuit was paretic, and the olivocerebellar visual relay pathway was degenerated. An extraretinal, efference copy signal of the eye position error must detect the ocular drift and generate the rebound bias. The neuropathological findings indicate that rebound nystagmus can be a sign of involvement confined to the olivocerebellar circuit and that nonvisual signals of eye position are monitored independently of this cerebellar system.

Simian virus 40 specific cytotoxic lymphocyte clones localize two distinct TSTA sites on cells synthesizing a 48 kD SV40 T antigen

Simian virus 40 specific antigenic sites (TSTA) which react with SV40 specific cytotoxic lymphocytes (CTL) were localized on the surface of mouse embryo fibroblasts (H-2b) transformed with a recombinant plasmid which contain SV40 large T antigen coding DNA sequences (0.65-0.37 map units). These cells (B6/pSV-20-GV) synthesize a large T antigen polypeptide of 48 kD and could be lysed with two independently isolated CTL clones which recognize distinct antigenic sites on SV40 transformed cell surface. These results suggest that at least two distinct TSTA sites are present in cells synthesizing only the amino terminal half of SV40 T antigen.

Effect of various dietary arginine: lysine ratios on performance, carcass composition and plasma amino acid concentrations of growing-finishing swine

Crossbred growing-finishing pigs (112 barrows, 48 gilts) were used to determine the effect of reducing excess dietary arginine, through feedstuff variation, on performance, carcass composition and plasma amino acid concentrations. Diets contained five, four, three or two times the NRC requirement for arginine. Lysine in all diets was formulated to be equal to NRC requirements, and all diets contained at least 100% of the NRC recommendations for all other essential amino acids. Initial weight, final weight and days on test for the grower phase were 26.7 kg, 44.2 kg and 28 d, respectively. Weight gain and gain/feed were not different among treatments but feed intake showed a quadratic response during the grower phase, being highest at four times the NRC requirement for arginine. Initial weight, final weight and days on test for the finisher phase were 44.2 kg, 96.9 kg and 67 d, respectively. Weight gain during the finisher phase and for the total experiment exhibited a quadratic response, being highest for the pigs fed the intermediate arginine levels. Gain/feed for the finisher phase followed the same trend as weight gain. Feed intakes for the finisher phase and total experiment were not different among treatments. Carcass data were collected on all barrows. There were no differences in hot carcass weight or adjusted average backfat among treatments. Loin eye area and percentage of lean decreased linearly as arginine level decreased in the diet. Plasma urea, arginine and orthinine concentrations decreased linearly with decreasing dietary arginine. Plasma lysine exhibited both a quadratic and a cubic response. The data indicate that reducing excess dietary arginine had little effect on performance or carcass composition and no consistent effect on plasma lysine of growing-finishing swine.

Effects of excess arginine with and without supplemental lysine on performance, plasma amino acid concentrations and nitrogen balance of young swine

Three experiments were conducted to determine the effects of excess arginine on performance, plasma amino acid levels and N balance of young pigs (initial weights 6.9, 7.0 and 10.3 kg, respectively). In a 28-d growth trial, various amounts of arginine (0 to 1.6%) were added to a conventional starter diet. Addition of arginine decreased (P less than .01) average daily feed intake (ADFI) and gain (ADG), but had no effect on feed efficiency (G/F). Plasma urea, arginine and ornithine concentrations were elevated (P less than .001) by the increasing dietary arginine levels at d 14 and 28. Plasma histidine levels were reduced (P less than .01) at d 28. Plasma lysine levels exhibited a cubic response (P less than .05) at d 14, but were not affected by excess arginine at d 28. In a second growth trial ADFI and ADG were decreased (P less than .05), but G/F was not affected by the addition of 1.6% dietary arginine. Lysine supplementation (0, .15 or .30%) increased performance in the absence of excess arginine, but the main effect of lysine was not significant for any performance criteria. As in the first experiment, plasma concentrations of urea, arginine and ornithine were increased (P less than .001) by the addition of arginine. Plasma histidine was not affected by either arginine or lysine. Plasma lysine levels were reduced (P less than .001) by dietary arginine and increased (P less than .001) by lysine. In a N balance experiment, addition of 1.6% dietary arginine increased N digestibility, but decreased apparent biological value. Nitrogen balance was not affected by added arginine. Lysine addition did not improve any of these three indices of N utilization. The inability of lysine supplementation to alleviate any of the adverse effects of excess arginine in young swine indicates that the reduced performance is caused by a generalized amino acid imbalance, and not by a specific interference with lysine utilization in the manner of a classical arginine-lysine antagonism.