Diagnostic and prognostic role of nitroglycerin-induced dilation in patients with suspected vasospastic angina, combined with ergonovine provocation test.

The diagnostic and prognostic role of nitroglycerin-induced dilation (NID) combined with ergonovine provocation test in patients with suspected VSA patients is not clear. A total of 438 consecutive patients who underwent the ergonovine provocation test for the diagnosis of vasospastic angina (VSA) were enrolled. Patients with VSA (n = 52) had a significantly greater coronary response to ergonovine (- 84.3 ± 10.5% vs. - 38.4 ± 17.9%, p < 0.001) and NID (26.3 ± 31.0% vs. 12.5 ± 19.0%, p < 0.001) than non-VSA patients. However, positive NID (more than 13.8% dilation, n = 170) showed a poor accuracy (AUC 0.64 [95% CI: 0.56-0.73], p = 0.001, sensitivity 60.4%, specificity 61.3%) for the diagnosis of VSA by ergonovine provocation test. Major adverse cardiovascular events (MACE) occurred more frequently in the VSA group than in the non-VSA group (9.6% vs. 2.2%, p = 0.006). In addition, the positive NID group showed a lower rate of MACE than the negative NID group (1.2% vs. 4.3%, p = 0.021). Interestingly, the group of VSA with negative NID had poor prognosis than any other combinations (Log-rank, p < 0.0001). Although NID had a limited role in the detection of VSA defined by ergonovine provocation test, NID combined with the ergonovine provocation test has an additive prognostic role in the clinical outcomes in patients with suspected VSA.

Cytotoxic effect of ergot alkaloids in Achnatherum inebrians infected by the Neotyphodium gansuense endophyte.

Ergonovine or ergonovinine was isolated from the aerial parts of endophyte (Neotyphodium gansuense) infected (E+) drunken horse grass (Achnatherum inebrians), neither of which existed in endophyte-free (E-) plants. Both of these ergot alkaloids had a cytotoxic effect on animal smooth muscle cells and increased cell growth inhibition with greater concentrations, in a significantly (P < 0.05) positive correlation. The median inhibitory concentrations (IC50) for ergonovine and ergonovinine were 71.95 and 72.75 µg/mL, respectively. These results indicate that endophytic ergot alkaloids may be the cause of drunken horse grass poisoning.

Ergot alkaloid transport across ruminant gastric tissues.

Ergot alkaloids cause fescue toxicosis when livestock graze endophyte-infected tall fescue. It is generally accepted that ergovaline is the toxic component of endophyte-infected tall fescue, but there is no direct evidence to support this hypothesis. The objective of this study was to examine relative and potential transport of ergoline and ergopeptine alkaloids across isolated gastric tissues in vitro. Sheep ruminal and omasal tissues were surgically removed and placed in parabiotic chambers. Equimolar concentrations of lysergic acid, lysergol, ergonovine, ergotamine, and ergocryptine were added to a Kreb's Ringer phosphate (KRP) solution on the mucosal side of the tissue. Tissue was incubated in near-physiological conditions for 240 min. Samples were taken from KRP on the serosal side of the chambers at times 0, 30, 60, 120, 180, and 240 min and analyzed for ergot alkaloids by competitive ELISA. The serosal KRP remaining after incubation was freeze-dried and the alkaloid species quantified by HPLC. The area of ruminal and omasal tissues was measured and the potential transportable alkaloids calculated by multiplying the moles of transported alkaloids per square centimeter of each tissue type by the surface area of the tissue. Studies were conducted to compare alkaloid transport in reticular, ruminal, and omasal tissues and to determine whether transport was active or passive. Ruminal tissue had greater ergot alkaloid transport potential than omasal tissue (85 vs 60 mmol) because of a larger surface area. The ruminal posterior dorsal sac had the greatest potential for alkaloid transport, but the other ruminal tissues were not different from one another. Alkaloid transport was less among reticular tissues than among ruminal tissues. Transport of alkaloids seemed to be an active process. The alkaloids with greatest transport potential were lysergic acid and lysergol. Ergopeptine alkaloids tended to pass across omasal tissues in greater quantities than across ruminal tissues, but their transport was minimal compared to lysergic acid and lysergol.

Effect of ergotamine and ergonovine on plasma concentrations of thyroid hormones and cortisol in cattle.

Plasma samples from two experiments were processed to determine whether ergot alkaloids associated with endophyte-infected tall fescue altered peripheral thyroxine (T4), triiodothyronine (T3), or cortisol concentrations in cattle. In Exp. 1, seven Angus steers (294 kg) received i.v. bolus injections of saline (SAL), ergonovine maleate (7 mg; EM), or ergotamine tartrate (7 mg; ET) at weekly intervals, and they received all treatments during the study. Blood was sampled every 15 min for 5 h, and treatments were given after h 1. Mean ambient temperature was 34 degrees C. Treatment x time affected plasma concentrations of T3 (P < .05) and of cortisol (P < .001) but not that of T4 (P > .2). Plasma T3 concentrations were not affected by SAL, whereas concentrations increased (P < .01) after either EM or ET treatment. Plasma cortisol concentrations were not altered by SAL or EM, but they were increased (P < .001) by ET treatment. In Exp. 2, six Holstein cows (499 kg) nursing calves received a bolus i.v. injection of SAL, EM (9.5 mg), or ET (9.5 mg) per estrous cycle, and all treatments were given over three cycles. Blood was sampled every 20 min for 5 h; treatments were given after h 1. Mean ambient temperature was 26 degrees C. Treatment x time affected T3 (P = .08) and cortisol (P < .001) and tended to influence (P = .16) T4 concentrations. Plasma T3, T4, and cortisol concentrations were not influenced by SAL treatment. Plasma T3 was higher (P < or = .01) after EM or ET treatment compared with pretreatment concentrations. Concentrations of T4 during the 4 h after EM and ET were increased (P < .001) compared with pretreatment. Plasma cortisol concentrations were not altered by EM but were increased (P < .001) by ET. Ergot alkaloids implicated as contributing agents to fescue toxicosis alter plasma concentrations of hormones important to metabolic and thermoregulatory functions in cattle.

Reproductive hormonal responses to ergotamine and ergonovine in cows during the luteal phase of the estrous cycle.

We conducted research to evaluate whether ergot alkaloids associated with endophyte-infected tall fescue could alter plasma concentrations of hormones important to reproductive function in cows. Six primiparous, estrous-cycling Holstein cows nursing calves received single i.v. injections of ergotamine tartrate, ergonovine maleate, or saline vehicle in a simple cross-over design. Each cow received one compound per estrous cycle, d 15 or 16 after estrus, and all compounds over three estrous cycles. Blood samples were collected at 20-min intervals for 40 min before and 240 min after treatments to assess plasma concentrations of prolactin, LH, FSH, and the response by PGF2alpha metabolite 13,14-dihydro-15-keto-prostaglandin F2alpha (PGFM). Ambient temperature and respiratory rates were measured hourly. Ambient temperature averaged 26 degrees C during data collection. Treatment x time was a significant source of variation for respiration rate and plasma concentrations of every hormone evaluated except FSH. Ergotamine elevated (P < .01) respiration rates 2 to 4 h after treatment. Ergotamine and ergonovine reduced (P < .001) plasma concentrations of prolactin for 2 to 4 h after treatment compared to concentrations before treatment. Plasma concentrations of LH were lowered (P < .01) by ergonovine during the 3rd h after treatment and by ergotamine during the 4th h after treatment. Most cows exhibited secretory PGFM responses after ergotamine and ergonovine treatments compared with an absence of a PGFM response in all cows after saline (P < or = .01). Results indicated that ergot alkaloids implicated as causative agents for fescue toxicosis can alter plasma concentrations of reproductive hormones during the late luteal phase of the estrous cycle in cows.

Subacute toxicity of ergometrine maleate in rats.

Ergot alkaloids, produced by the fungus Claviceps purpurea, are found in small amounts in foodstuffs. The human disease ergotism, caused by high intake of ergot alkaloids, is well known; however, little is known about the toxicity of these compounds. The subacute toxicity of an ergot alkaloid, ergometrine maleate, was therefore studied. Sprague-Dawley rats were treated with 0, 2, 10, 50 and 250 mg ergometrine maleate/kg diet for 4 wk. Plasma glucose levels were decreased in females at 50 and 250 mg/kg. Thyroxin levels were decreased at 50 (males only) and 250 mg/kg. At the high dose level, organ weights of heart, liver, ovaries and kidneys were increased. In male rats a slight dose-related increase in the incidence of enlarged mediastinal lymph nodes and, to some extent, of enlarged parathymal lymph nodes, was seen. Histopathological examination revealed evidence of increased glycogen storage in the liver of animals treated with 250 mg/kg. The no-observed-effect level in this study was 10 mg/kg.

Evaluation of a dosing method for studying ergonovine effects in cattle.

We evaluated the feasibility of using miniosmotic pumps as a way to continuously treat cattle with a singular ergot alkaloid (ergonovine) of known content, thus mimicking the natural fescue toxicosis disease state, but allowing study of specific alkaloid effects. Dosing animals with increasing amounts of ergonovine via miniosomotic pumps, followed by daily acquisition of plasma samples for high-performance liquid chromatographic determination of the alkaloid, resulted in stepwise increases in plasma ergonovine concentration. However, despite the detectable blood concentration of ergonovine, calves did not have typical clinical signs of ergot alkaloid toxicosis. Similarly, serum prolactin concentration was unaffected by ergonovine in these cattle, implicating some other alkaloid of endophyte-infested fescue as causative of the usual prolactin-suppressive response. The results confirm use of this animal dosing method to study biological effects of singular purified alkaloids of known amount, without bioavailability concerns. Thus, this dosing method will facilitate studies to determine the harmful effects of individual alkaloids found in toxic tall fescue, and ultimately, to alleviate their costly effects in cattle, horses, and other species.

The effect of alkaloids and seed extracts of endophyte-infected tall fescue on prolactin secretion in an in vitro rat pituitary perfusion system.

The objective of this research was to measure the effects of endophyte-infected tall fescue seed extract and various alkaloids associated with the endophyte on in vitro prolactin secretion by rat hemipituitaries. Rat anterior pituitaries (AP) were dissected into halves and placed in temperature-controlled culture chambers (37 degrees C). The tissue was perfused with culture media at a flow rate of 12 mL/h. After perfusion for at least 90 min with control media, AP halves were exposed to their respective treatments for 15 min before they were returned to the control media. The treatments for Exp. 1 were .01 micrograms of alpha-ergocryptine/mL of culture medium, .01 microgram of ergonovine/mL of culture medium, .01 gram-equivalents of endophyte-infected tall fescue seed/mL of culture medium, and .01 gram-equivalents of endophyte free tall fescue seed/mL of culture medium. Treatments for Exp. 2 consisted of 10(-4), 10(-6), and 10(-8) M concentrations of perloline, N-formyl loline, N-acetyl loline, N-methyl loline, and alpha-ergocryptine. alpha-Ergocryptine suppressed (P less than .10) prolactin secretion in both experiments. Ergonovine and perloline both stimulated (P less than .10) prolactin secretion. The loline alkaloids (N-formyl loline, N-acetyl loline, N-methyl loline) had no effect on prolactin secretion. The endophyte-infected seed extract treatment suppressed (P less than .10) prolactin secretion. The endophyte-free seed extract treatment had no effect on prolactin secretion. In Exp. 2, prolactin secretion from AP responded to alpha-ergocryptine treatment in a dose-dependent fashion.(ABSTRACT TRUNCATED AT 250 WORDS)