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PubMed2005

Toxin-producing ability among Bacillus spp. outside the Bacillus cereus group.

A total of 333 Bacillus spp. isolated from foods, water, and food plants were examined for the production of possible enterotoxins and emetic toxins using a cytotoxicity assay on Vero cells, the boar spermatozoa motility assay, and a liquid chromatography-mass spectrometry method. Eight strains produced detectable toxins; six strains were cytotoxic, three strains produced putative emetic toxins (different in size from cereulide), and one strain produced both cytotoxin(s) and putative emetic toxin(s). The toxin-producing strains could be assigned to four different species, B. subtilis, B. mojavensis, B. pumilus, or B. fusiformis, by using a polyphasic approach including biochemical, chemotaxonomic, and DNA-based analyses. Four of the strains produced cytotoxins that were concentrated by ammonium sulfate followed by dialysis, and two strains produced cytotoxins that were not concentrated by such a treatment. Two cultures maintained full cytotoxic activity, two cultures reduced their activity, and two cultures lost their activity after boiling. The two most cytotoxic strains (both B. mojavensis) were tested for toxin production at different temperatures. One of these strains produced cytotoxin at growth temperatures ranging from 25 to 42 degrees C, and no reduction in activity was observed even after 24 h of growth at 42 degrees C. The strains that produced putative emetic toxins were tested for the influence of time and temperature on the toxin production. It was shown that they produced putative emetic toxin faster or just as fast at 30 as at 22 degrees C. None of the cytotoxic strains produced B. cereus-like enterotoxins as tested by PCR or by immunological methods.

Animals↗
PubMed1995

Biological activities of staphylococcal enterotoxin type A mutants with N-terminal substitutions.

The purpose of this study was to examine the importance of certain N-terminal amino acid residues of staphylococcal enterotoxin type A (SEA) for biological activity. The results confirm our previous observation that Asn-25, Phe-47, and Leu-48 are important for SEA's emetic and superantigen activities. Substitutions at six other sites (Leu-12, Lys-14, Ser-16, Asp-45, Gln-46, and Thr-51) did not reveal any additional residues required for biological activity. Mutant SEAs with substitutions at 25, 47, or 48 all had decreased T-cell stimulatory activity, with the mutants at position 47 being the most defective. Results of a competition assay for binding to the major histocompatibility complex (MHC) class II-expressing cell line Raji suggested that the decreased superantigen activities of the mutants with substitutions at positions 47 and 48 are due to poor interactions with MHC class II molecules, whereas the defects of the mutants at position 25 are a consequence of faulty interactions with T-cell receptors. With respect to emetic activity in rhesus monkeys, the mutants at position 25 or 48 exhibited decreased but significant activity. Interestingly, the two mutants at position 47 had different emetic activities; SEA-F47G was nonemetic when administered intragastrically at 500 micrograms per animal, whereas SEA-F47S was emetic at this dosage. Since the mutants at position 47 were equally defective for superantigen activity, this further supports our previous suggestion of an incomplete correlation between SEA's emetic and superantigen activities.

Animals↗
PubMed1985

Ipecacuahana induced emesis in the treatment of self-poisoned adults.

One hundred consecutive adult patients presenting to an Accident and Emergency Department following intentional self-poisoning were given 50 to 80 ml Paediatric Ipecacuahana Emetic Mixture BP as an emetic, together with two or three glasses of strong orange juice. A satisfactory emetic result was obtained in 99 patients. No toxic effects were noted in these patients, or in the one patient in whom emesis did not occur, and who subsequently refused gastric lavage. The potential toxicity of Ipecacuahana Syrup itself is discussed, and attention drawn to the lower Emetine content of Paediatric Ipecacuahana Emetic Mixture (BP), rather than that of the formulations used in previously published reports. The use of Paediatric Ipecacuahana Emetic Mixture B.P. in adults is effective and safe in this dosage.

Adolescent↗
PubMed2001

Combination of transcutaneous electrical nerve stimulation and ondansetron in preventing cisplatin-induced emesis.

OBJECTIVE: To find out whether the combination of transcutaneous electrical nerve stimulation (TENS) and ondansetron had an increased antiemetic effect. MATERIALS AND METHODS: Fourteen testis and 11 bladder cancer patients were scheduled for 4 cycles of bleomycin-etoposide-cisplatin (BEP) or methotrexate-vinblastine-etoposide-cisplatin (MVEC) combination chemotherapy, respectively. At each cycle the whole cisplatin dose was given in 1 day that is 100 mg/m(2)/day in the BEP and 70 mg/m(2)/day in the MVEC protocols. Ondansetron was given at a dose of 12 mg/day and TENS was applied by commercially available 'Relief Band'(Maven Labs, Inc., Citrus Heights, Calif., USA). The first 3 cycles of each case were blindly randomized to one of the following regimens; TENS vs. ondansetron vs. a combination of both. The regimens were applied during the administration of cisplatin and the patients were asked to report their nausea according to a scale between 0 to 10. Also for each regimen the number of emetic attacks experienced during the administration of cisplatin was recorded by the same observer. Then the scores of each regimen were compared. RESULTS: The mean nausea scores for regimens TENS, ondansetron and TENS + ondansetron were found to be 5.12 +/- 2.54, 3.0 +/- 1.71 and 0.8 +/- 0.96, respectively. Ondansetron was better than TENS in preventing nausea (p = 0.000). However the combination of TENS and ondansetron resulted in a significant decrease in nausea scores when compared to TENS alone (p = 0.000) or ondansetron alone (p = 0.000). The mean number of emetic attacks for the TENS, ondansetron and TENS + ondansetron regimens were 3.16 +/- 1.84, 1.64 +/- 1.44 and 0.56 +/- 0.82, respectively. A statistically significant difference was present between the number of emetic attacks observed with the TENS + ondansetron combination and TENS alone (p = 0.000) or ondansetron alone (p = 0.001). Ondansetron was again better than TENS in preventing emetic attacks (p = 0.001). CONCLUSION: The use of TENS as an adjunct to ondansetron therapy has provided significant benefit in preventing nausea and emetic attacks caused by cisplatin.

Adult↗
PubMedDate not supplied

Modified oral ondansetron regimen for cyclophosphamide-induced emesis in lupus nephritis.

OBJECTIVE: To evaluate the antiemetic efficacy of a modified regimen of oral ondansetron and dexamethasone in patients with lupus nephritis undergoing treatment with cyclophosphamide whose conventional antiemetic regimen had failed. DESIGN: A before-after prospective observational pilot project. SETTING: A federal research hospital. PATIENTS: Fourteen outpatients with lupus nephritis receiving intravenous cyclophosphamide 0.75-1.0 g/m2 had previously experienced chemotherapy-induced emetic events (vomiting or retching) while receiving a standard combination intravenous antiemetic regimen. The regimen consisted of four doses of thiethylperazine 10 mg and diphenhydramine 25 mg every 6 hours, and two doses of lorazepam 0.5 mg every 6 hours starting at 1 hour prior to cyclophosphamide. A subset of 8 patients previously completed a blinded study in which they received the intravenous formulation of ondansetron (4 doses of 4-16 mg q4h) administered orally beginning 30 minutes prior to the cyclophosphamide infusion. MAIN OUTCOME MEASURES: The number of emetic events and cost of drug administration were assessed for the modified ondansetron intervention and compared with those of the standard antiemetic regimen. The incidence of emetic events and visual analog nausea scores for the subset of eight patients were also evaluated. INTERVENTIONS: To account for the delayed onset of emesis associated with cyclophosphamide, patients received both ondansetron 8 mg orally every 4 hours (3 doses) and dexamethasone 10 mg orally (1 dose) beginning 4 hours after the cyclophosphamide infusion. This is different from the manufacturer's recommended dose schedule, in which ondansetron is administered prior to chemotherapy. RESULTS: No emetic events were observed following the administration of oral ondansetron/dexamethasone. The 95% confidence interval for the true rate of emesis was 0% to 19.3%. There was a significant difference in efficacy between ondansetron/dexamethasone and the triple antiemetic regimen (p < 0.0002). None of the patients experienced adverse effects while receiving the ondansetron/dexamethasone regimen. Cost comparisons (including admixture and nursing administration times) for standard combination therapy and oral ondansetron/dexamethasone were $109.09 and $70.24, respectively. No difference in emetic events or nausea ratings was observed between oral ondansetron/dexamethasone tablets and oral administration of ondansetron using the intravenous formula. CONCLUSIONS: This study suggests that a modified oral ondansetron/dexamethasone regimen is safe and efficacious, and costs less than alternative regimens to prevent cyclophosphamide-induced emesis in patients with lupus nephritis.

Administration, Oral↗
PubMed1992

Stratified, randomized, double-blind comparison of intravenous ondansetron administered as a multiple-dose regimen versus two single-dose regimens in the prevention of cisplatin-induced nausea and vomiting.

PURPOSE: This study compares the efficacy and safety of two single-dose regimens with the approved three-dose regimen of ondansetron in the prevention of cisplatin-induced emesis. PATIENTS AND METHODS: This multicenter study was a stratified, randomized, double-blind, and parallel group design. Chemotherapy-naive inpatients were randomized to receive intravenous (IV) ondansetron (Zofran; Glaxo Inc, Research Triangle Park, NC) 0.15 mg/kg times three doses, every 4 hours or a single 8-mg or 32-mg dose followed by two saline doses that began 30 minutes before cisplatin administration. Cisplatin (high-dose > or = 100 mg/m2 or medium-dose 50 to 70 mg/m2) was given as a single infusion (< or = 3 hours). Patients were monitored for emetic episodes, adverse events, and laboratory safety parameters for 24 hours after cisplatin administration. RESULTS: A total of 699 patients (359 high-dose, 340 medium-dose) were enrolled. Of these, 618 were assessable for efficacy (15 ineligible, 66 protocol deviations). The 32-mg dose was superior to the 8-mg single dose with regard to total number of emetic episodes (high-dose, P = .015; medium-dose, P < .001), complete response (no emetic episodes: high-dose, 48% v 35%; P = .048; medium-dose, 73% v 50%; P = .001) and failure rate (> 5 emetic episodes, withdrawn or rescued: high-dose, 20% v 34%; P = .018; medium-dose, 9% v 23%; P = .005). The 32-mg single dose was also superior to the 0.15 mg/kg times three dose regimen with regard to total number of emetic episodes (medium-dose, P = .033) and failure rate (high-dose, 20% v 36%; P = .009; medium-dose, 9% v 22%; P = .011). Ondansetron was well tolerated. The most common adverse event was headache. An approximate 10-fold increase in the incidence of clinically significant transaminase elevations was observed in the high-dose versus medium-dose cisplatin strata (aspartate aminotransferase [AST], 6.5% v 0.7%; serum alanine aminotransferase [ALT], 5.0% v 0.3%). CONCLUSION: A 32-mg single dose of ondansetron is more effective than a single 8-mg dose and is at least as effective as the standard regimen of 0.15 mg/kg times three doses in the prevention of cisplatin-induced acute emesis.

Adult↗
PubMed2004

Diphenidol has no actual broad antiemetic activity in dogs and ferrets.

Previous studies showed that diphenidol was effective on emetogens-induced pica, eating of non-nutritive substances, in rats, a model analogous to emesis in other species. We evaluated the actual antiemetic activity of diphenidol against four emetic stimuli in the dog and ferret, animals that possess an emetic reflex. In dogs, emetic responses to apomorphine were significantly prevented by diphenidol (3.2 mg/kg, i.v.), whereas diphenidol (3.2 mg/kg, i.v. x 2) showed a weak inhibition to the vomiting evoked by cisplatin. In ferrets, diphenidol (10 mg/kg, i.p.) exhibited a weak antiemetic activity on the emesis induced by copper sulfate and had no activity on emesis by loperamide. On the other hand, CP-122,721, a NK1-receptor antagonist, significantly reduced the emetic episodes to all four stimuli. These results suggest that the prediction of antiemetic activity of compounds in animals lacking an emetic reflex does not always correspond with actual antiemetic activity.

Animals↗
PubMed2001

Effects of dexamethasone on emesis in cats sedated with xylazine hydrochloride.

OBJECTIVE: To determine antiemetic efficacy of prophylactic administration of dexamethasone and its influence on sedation in cats sedated with xylazine hydrochloride. ANIMALS: 6 healthy adult cats (3 males and 3 females). PROCEDURE: The prophylactic antiemetic effect of 4 doses of dexamethasone (1, 2, 4, and 8 mg/kg of body weight, IM) or saline (0.9% NaCl) solution (0.066 ml/kg, IM) administered 1 hour before administration of xylazine (0.66 mg/kg, IM) was evaluated. Cats initially were given saline treatment (day 0) and were given sequentially increasing doses of xylazine on days 7, 14, 21, and 28. After xylazine injection, all cats were observed for 30 minutes to allow assessment of frequency of emesis and time until onset of the first emetic episode. The influence of dexamethasone on xylazine-induced sedation in these cats also was evaluated. RESULTS: Prior treatment with 4 or 8 mg/kg of dexamethasone significantly reduced the frequency of emetic episodes and also significantly prolonged the time until onset of the first emetic episode after xylazine injection. Time until onset of the first emetic episode also was significantly prolonged for dexamethasone at a dose of 2 mg/kg. Time until onset of sedation after administration of xylazine was not altered by administration of dexamethasone. CONCLUSIONS AND CLINICAL RELEVANCE: Dexamethasone (4 or 8 mg/kg, IM) significantly decreased the frequency of emetic episodes induced by xylazine without compromising sedative effects in cats. Dexamethasone may be used prophylactically as an antiemetic in cats treated with xylazine.

Adrenergic alpha-Agonists↗
PubMed1999

Emesis in the shrew mouse (Suncus murinus) induced by peroral and intraperitoneal administration of staphylococcal enterotoxin A.

Peroral and intraperitoneal administration of staphylococcal enterotoxin A (SEA) to Suncus murinus elicited an emetic response. The 50% emetic dose of SEA by peroral administration was found to be 32 microg per kg of body weight, whereas that by intraperitoneal administration was 3 microg per kg. Multiple emetic responses occurred 70 to 108 min after peroral administration of an emetic dose of SEA. Similar responses occurred 65 to 102 min after intraperitoneal injection of an emetic dose of SEA. No significant difference in vomiting was observed between male and female animals. Anti-SEA serum neutralized SEA-induced emesis in S. murinus. These findings indicate that S. murinus may serve as a suitable animal model to study the enterotoxigenicity of SEA.

Administration, Oral↗
PubMed1982

Incidence of ketamine-induced emesis in cynomologus monkeys (Macaca fascicularis) used for staphylococcal enterotoxin bioassay.

Ten (24%) of 41 cynomologus monkeys (Macaca fascicularis) showed emetic response to 2.5-20 mg/Kg of ketamine injected i.m. Reduction of the levels of ketamine to one half or less of the emetic level resulted in faster recovery from sedation yet provided adequate time for intubation and subsequent intragastric feeding of staphylococcal enterotoxin (SE) in only 6 of the 10 monkeys without emesis. The onset of the first emetic episode with ketamine was similar to that induced by staphylococcal enterotoxin A (SEA). Cynomologus monkeys showing emetic response to ketamine could still be used for SE bioassay if an experimentally determined non-emetic dose for individual monkeys is employed for sedation.

Animals↗
PubMed1982

Vomiting induced by cyclophosphamide and phosphoramide mustard in cats.

Cyclophosphamide and phosphoramide mustard produce significant vomiting. Cyclophosphamide is metabolized to phosphoramide mustard, which may ultimately contribute to vomiting after cyclophosphamide administration. The role of the chemoreceptor trigger zone (CTZ) in vomiting caused by these agents is unknown. We studied the emetic syndromes produced by iv and intracerebroventricular cyclophosphamide and phosphoramide mustard in unanesthetized normal and CTZ-ablated cats. Iv cyclophosphamide produced vomiting unpredictably, with a mean latency of 54 +/- 9 mins (mean +/- SE) in cats that vomited. A dose-response relationship was found for phosphoramide mustard-induced emesis. A dose of 200 mg/kg was consistently effective, with a mean latency of 127 +/- 6 mins. Neither agent produced predictable emesis by the intracerebroventricular route of administration. One of four CTZ-ablated cats vomited after 300 mg/kg of cyclophosphamide. Since cyclophosphamide was an unpredictable emetic stimulus, it was not possible to further evaluate the effect of CTZ ablation on cyclophosphamide-induced vomiting. However, CTZ-ablated cats given 200 mg/kg of phosphoramide mustard vomited significantly less frequently (P = 0.05 by chi-square test) and with a longer latency than nonablated animals. A temporary, severe neurotoxic reaction was observed in cats receiving greater than or equal to 3400 mg/kg of cyclophosphamide, which may have had an inhibitory effect on emesis. Phosphoramide mustard was found to be a potent emetic stimulus in cats and may contribute to the emetic response following cyclophosphamide administration. Analysis of latency data suggests that in the cat other cyclophosphamide metabolites may also contribute to the emetic syndrome.

Animals↗
PubMed1982

Cisplatin-induced emesis in the Ferret: a new animal model.

The ferret, a carnivore weighing about 1 kg, was evaluated for its potential use in testing drugs for emetic and antiemetic activity. An acute emetic response to apomorphine indicated that the ferret can respond to emetic stimuli and suggested that the ferret has an emetic chemoreceptor trigger zone. Cisplatin produced a dose-related emetic response. Antagonism with metoclopramide provided complete protection from cisplatin-induced emesis. The results of these initial studies indicate that the ferret may be a useful species in emesis research.

Animals↗
PubMed1994

Ondansetron: prevention of nausea & vomiting in cisplatin based chemotherapy.

Ondansetron in the prophylaxis of Cisplatin-induced emesis and nausea. The 5-HT3 antagonist ondansetron clearly offers a new approach to the control of Cisplatin-induced emesis and has been evaluated in Thailand. To evaluate anti-emetic efficacy of ondansetron in the prevention of nausea and vomiting induced by Cisplatin containing cancer chemotherapy regimen, we carried out an open multicentre study from January 1991 to December 1992. In this study, patients receiving Cisplatin based chemotherapy received ondansetron 32 mg as a single intravenous dose over 15 minutes prior to the administration of Cisplatin. This was followed by oral ondansetron 8 mg three times a day, preferably one hour before each meal for 5 days. All patients were chemotherapy naive in-patients and were at least 18 years or older with Karnofsky performance status of at least 60 per cent. The number of emetic episodes, nausea and food intake were recorded during the 24 hours following Cisplatin administration. A total of 103 patients were recruited with 84 (81.6%) evaluable patients (48 men and 36 women) scheduled to receive cisplatin chemotherapy at dose 60 mg/m2 or more (60-100 mg/m2), either as single agent or combination therapy. Complete response (complete control of emesis) was achieved in 60 per cent; major response (1-2 emetic episodes) was 13 per cent; minor response (3-5 emetic episodes) was 13 per cent; and failure (5+ emetic episodes) was 10 per cent. Side effects were very mild and not significant. We conclude that ondansetron is efficacious in protecting patients from Cisplatin induced emesis and nausea.

Adult↗
PubMed2001

Electrophysiologic and hemodynamic effects of apomorphine in dogs.

Apomorphine is a dopamine receptor agonist used as an emetic, for Parkinson's disease, and for treating erectile dysfunction. This study was conducted to monitor cardiovascular function in dogs given the standard emetic dose (0.05 mg/kg) or 10 times that. Measurements were made during baseline and at 1, 5, 15, 30, 45, and 60 min after iv administration. There were no changes produced by the 0.05 mg/kg dose of apomorphine except for a decrease in mean systemic arterial pressure (AoPm) at the 1 through 15 min recordings. For the 0.5 mg/kg dose, there were reductions in systemic vascular resistance at the 1 and 5 min recordings and in AoPm at the 1 through 60 min recordings. Although not significant, when AoPm fell, heart rate, stroke volume, and cardiac output tended to increase. Action potentials were recorded from superfused Purkinje and endocardial ventricular fibers while exposed to 10(-9) to 10(-5) M apomorphine (10(-10) M is considered therapeutic and 10(-7) M is considered lethal). There were no changes in action potential characteristics of Purkinje fibers, but action potential duration at 90% repolarization prolonged approximately 10-12% in endocardium at concentrations of 10(-6) M and greater. At the usual emetic dose (0.05 mg/kg) apomorphine resulted in no signs of cardiovascular toxicity and, at 0.5 mg/kg, cardiovascular changes were minimal. The emetic dose is higher than that for Parkinson's disease or erectile dysfunction; thus apomorphine appears to be a safe compound for clinical use in dogs and by extrapolation to man.

Action Potentials↗
PubMed1994

Antiemetic effects of 5-HT1A agonists in the pigeon.

Ditolyguanidine (DTG) induced a dose-dependent emetic response in pigeons, with 100% of the birds vomiting after 5.6 mg/kg. Retching and vomiting originally induced by DTG could be conditioned to the test situation. Both the unconditioned and conditioned emetic responses were dose-dependently blocked by 8-hydroxy-(di-n-propylamino)tetralin (8-OH-DPAT) and LY228729, agonists at the 5-HT1A subtype of serotonin receptor, but not by the 5-HT3, antagonist tropisetron. Higher doses (0.25-0.5 mg/kg) of tropisetron exhibited intrinsic emetic activity which could also be prevented by 8-OH-DPAT. NAN-190, a putative 5-HT1A partial agonist, produced both an antiemetic response when administered before DTG and also attenuated the antiemetic effects of 8-OH-DPAT. Pentobarbital blocked the conditioned, but not the unconditioned DTG-induced emesis. These results support the possibility that 5-HT1A agonists exhibit antiemetic activity against a broad range of emetic stimuli, including conditioned vomiting which is usually resistant to pharmacological attenuation.

Animals↗
PubMed1981

Inhibition by morphine and morphine-like drugs of nicotine-induced emesis in cats.

The effect of morphine, methadone and pethidine injected into the cerebral ventricle of the unanesthetized cat upon emesis produced by nicotine induced similarly was investigated. Morphine and morphine-like drugs depress or abolish the emetic effect of nicotine. The inhibitory effect of morphine, methadone and pethidine is observed after a transient emetic action of these drugs. The emetic and anti-emetic action of morphine, methadone and pethidine can perhaps be ascribed to an agonist/antagonist activity. Further, the possible site of inhibitory action of morphine and morphine-like drugs on the emesis produced by nicotine may be the area postrema of fourth ventricle.

Animals↗
PubMed1988

Characterization of radiation-induced emesis in the ferret.

Forty-eight ferrets (Mustela putorius furo) were individually head-shielded and radiated with bilateral 60Co gamma radiation at 100 cGy min-1 at doses ranging between 49 and 601 cGy. The emetic threshold was observed at 69 cGy, the ED50 was calculated at 77 cGy, and 100% incidence of emesis occurred at 201 cGy. With increasing doses of radiation, the latency to first emesis after radiation decreased dramatically, whereas the duration of the prodromal period increased. Two other sets of experiments suggest that dopaminergic mechanisms play a minor role in radiation-induced emesis in the ferret. Twenty-two animals were injected either intravenously or subcutaneously with 30 to 300 micrograms/kg of apomorphine. Fewer than 50% of the animals vomited to 300 micrograms/kg apomorphine; central dopaminergic receptor activation was apparent at all doses. Another eight animals received 1 mg/kg domperidone prior to either 201 (n = 4) or 401 (n = 4) cGy radiation and their emetic responses were compared with NaCl-injected-irradiated controls (n = 8). At 201 cGy, domperidone significantly reduced only the total time in emetic behavior. At 401 cGy, domperidone had no salutary effect on radiation-induced emesis. The emetic responses of the ferret to radiation and apomorphine are compared with these responses in other vomiting species.

Animals↗
PubMed1984

Behavioral and electrophysiological studies of peptide-induced emesis in dogs.

The electrophysiological responses of neurons in the canine area postrema (AP) to ionophoretic application of neuropeptides and transmitters were studied and correlated with the presence or absence of an emetic response on systemic administration. Of 17 common neuropeptides 11 were emetic when applied systemically at doses of 0.03-0.35 mg/kg. The emesis was dose dependent and was no longer observed in animals with chronic ablation of the AP. The responses of 122 AP single units were recorded. Neurons were silent at rest, and most were excited by glutamate, apomorphine, and dopamine. Excitatory responses to each of eight emetic peptides were recorded in 22-65% of cells studied; no responses were found to two peptides that were not emetic. The response to glutamate was always a brief, high-frequency discharge; the responses to all 13 other excitatory substances were of long latency, low frequency, and long duration. With high ionophoretic current or multiple applications, units would frequently become spontaneously active for many minutes or longer. The similarity of response of so many substances on small neurons suggests a common ionic or metabolic mechanism underlying the response. The direct correlation between the occurrence of emesis on systemic administration and the presence of excitatory receptors on AP neurons provides strong support for the proposed role of the AP as the chemoreceptor trigger zone for emesis.

Action Potentials↗