Stomach Lavage Research Articles

Особенности цитоморфологических изменений клеток печени, желудка и бронхоальвеолярного лаважа у экспериментальных животных при ингаляционной затравке хлопковой пылью.

Особенности цитоморфологических изменений клеток печени, желудка и бронхоальвеолярного лаважа у экспериментальных животных при ингаляционной затравке хлопковой пылью.

Лечение химических ожогов пищевода у детей

Objective . To study the treatment efficacy of chemical burns of the esophagus in children with different grades of lesion. Material and methods . For the last seven years in Dnipropetrovsk Regional Children’s Clinical Hospital there were 192 children on treatment with a diagnosis of chemical burn of the esophagus, out of them 108 (56.25%) boys and 84 (43.75%) girls, and prevailed children aged 1-3 years who made up 102 (53.1%). Among damaging agents caused esophageal burns were more often caustic ones 95 (49.47%). In most cases, there was grade II of lesion of esophageal burns in 71 (36.98%) children. Treatment of post-burn esophagitis includes detoxification, stomach lavage, pain management, antibiotic therapy, short course of corticosteroids. Estimation of the patient’s status provided during the first twenty-four hours. Further the restoration of esophageal patency was conducted with the use of instrumental methods of treatment. The main method of corrosive strictures of esophagus was gullet bougienage and dilation. Results . The patients of the study group were treated using bougie over guidewire dilators. Application of this methodology in treatment of patients with the esophageal burns allowed considerably reduce the amount of cicatrical esophageal stenosis, as well as such complications as perforations and mediastinitis. Conclusion . Proper provision of primary care and the selection of correct diagnostic and treatment tactics of patients with chemical burns of the esophagus helps to reduce complications and disability in children with this pathology.

Low trophic level diet of juvenile southern elephant seals Mirounga leonina from Marion Island: a stable isotope investigation using vibrissal regrowths

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 577:237-250 (2017) - DOI: https://doi.org/10.3354/meps12240 Low trophic level diet of juvenile southern elephant seals Mirounga leonina from Marion Island: a stable isotope investigation using vibrissal regrowths Nico Lübcker1,*, Ryan R. Reisinger1,4, W. Chris Oosthuizen1, P. J. Nico de Bruyn1, André van Tonder1, Pierre A. Pistorius2,3, Marthán N. Bester1 1Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield 0028, Pretoria, South Africa 2Marine Apex Predator Research Unit, Institute for Coastal and Marine Research, Nelson Mandela Metropolitan University, South Campus, Port Elizabeth 6031, South Africa 3DST/NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology, Nelson Mandela Metropolitan University, South Campus, Port Elizabeth 6031, South Africa 4Present address: Centre d’Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, 79360 Villiers-en-Bois, France *Corresponding author: nlubcker@zoology.up.ac.za ABSTRACT: Insight into the trophic ecology of marine predators is vital for understanding their ecosystem role and predicting their responses to environmental change. Juvenile southern elephant seals (SES) Mirounga leonina are considered generalist predators within the Southern Ocean. Although mesopelagic fish and squid dominate their stomach lavage samples, the stable isotope profile captured along the length of sampled vibrissae of young SES at Macquarie Island, southwest Pacific Ocean (54.5°S, 158.9°E) recently emphasized the contribution of crustaceans to their diet (likely Euphausia superba). Herein, we used the stable isotope values of sampled vibrissal regrowths with known growth histories to assess the diet of juvenile SES at Marion Island, southern Indian Ocean (46.8°S, 37.8°E) on a temporally integrated basis. We specifically aimed to quantify the possible contribution of crustaceans to the diet of juvenile SES. Sequentially (chronologically) sampled vibrissal regrowths of 14 juvenile SES produced fine-scale dietary information spanning up to 9 mo. The depleted stable isotope signatures of nitrogen (δ15N) (8.5 ± 0.6‰) and carbon (δ13C) (-20.3 ± 0.1‰) measured during the period of independent foraging suggested the use of a lower trophic level diet within the Polar Frontal Zone. A mixing model predicted that up to 76% of juvenile SES diet comprised crustaceans, consisting of 2 crustacean groups, each contributing 26% (credible interval, CI: 13-39%) and 50% (CI: 35-64%) to their diets, presumably representing subantarctic krill species. This first utilisation of the isotopic signature captured along the length of vibrissal regrowths confirms the inclusion and importance of crustaceans in the diet of juvenile SES. KEY WORDS: Crustaceans · Diet · Marine mammals · Pinnipeds · Stable isotopes · Vibrissae · Whiskers Full text in pdf format Supplementary material PreviousNextCite this article as: Lübcker N, Reisinger RR, Oosthuizen WC, de Bruyn PJN, van Tonder A, Pistorius PA, Bester MN (2017) Low trophic level diet of juvenile southern elephant seals Mirounga leonina from Marion Island: a stable isotope investigation using vibrissal regrowths. Mar Ecol Prog Ser 577:237-250. https://doi.org/10.3354/meps12240 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 577. Online publication date: August 18, 2017 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2017 Inter-Research.

Comparative dietary ecology of turtles (Chelodina burrungandjii and Emydura victoriae) across the Kimberley Plateau, Western Australia, prior to the arrival of cane toads

Food webs in north-western Australian rivers exist in dynamic environments and will be influenced by land use practices, invasion of toxic cane toads (Rhinella marina) and the effects of climate change on river flows. Baseline studies are needed to understand aquatic food webs before these impacts. In the present study, we investigated the diets of two turtles (Emydura victoriae and Chelodina burrungandjii) in four upland rivers across a gradient of rainfall and land uses in the Kimberley Plateau of Western Australia. We captured turtles by snorkelling and recovered their prey by stomach lavage. We enumerated 2720 prey items from 390 E. victoriae samples and 308 prey items from 155 C. burrungandjii samples. Prey compositions distinguished E. victoriae as an omnivorous generalist relying on a diversity of animal and plant prey and C. burrungandjii as a piscivorous specialist, but with both species as likely predators of toxic cane toad eggs or tadpoles. Comparisons among the rivers showed variation in diets for both species that reflect differences in prey availability and location-specific food webs. Terrestrially based food sources were observed in 26% of E. victoriae samples and 3% of C. burrungandjii samples, which indicates the importance of the aquatic–terrestrial interface and land use practices within these rivers.

Assessment of patients who presented to the emergency department with mushroom poisoning

This study aimed to assess the demographic characteristics, emergency department (ED) complaints, laboratory findings, and latent phase periods of patients who presented to the ED due to mushroom poisoning (MP) as well as the efficacy of conventional and hemofiltration therapies. The study was conducted on patients who presented to the ED with MP between 2010 and 2012. The patient's demographic characteristics, complaints at the ED, latent phases, laboratory findings, and treatments of MP cases were evaluated. The mean age of patients was 38.03 ± 15.96, where 63.8% of them were female and 36.2% were male. Visits occurred most frequently in the autumn (32.6%). When presenting to the ED, the most frequent complaint was nausea-vomiting. The aspartate aminotransferase (AST), alanine aminotransferase (ALT), international normalised ratio (INR), and blood urea nitrogen values of patients with a latent phase between 0 h and 5 h were significantly lower than the values of patients with a latent phase between 6 h and 24 h. In this study, 62% of the patients (n = 36) had stomach lavage and received activated charcoal. Altogether, 55.2% of the patients had received conventional therapy, 37.9% of them received hemofiltration, and all of them received supportive treatment. The AST, ALT, and INR values of those who had received hemofiltration and conventional therapies were significantly higher than of those who received only supportive treatment (p < 0.01). Hemofiltration, in combination with conventional therapy, seems to be an effective treatment for reducing mortality in suspected MP cases involving late acting toxins.

GW24-e1715 Clinical analysis of 19 patients with arrhythmias caused by acute aconitine poisoning

ObjectivesTo explore clinical characteristics and emergency treatment of patients with arrhythmias caused by acute aconitine poisoning.MethodsWe conducted a retrospective analysis during the period of 2010 to 2012, Clinical data of...

Colchicine intoxication: a report of two suicide cases

Colchicine, an old and well-known drug, is an alkaloid extracted from Colchicum autumnale and related species. Colchicine inhibits the deposition of uric acid crystals and is an inhibitor of mitosis. Nausea, vomiting, abdominal pain, and diarrhea, with a massive loss of fluid and electrolytes are the first clinical symptoms of colchicine poisoning. Stomach lavage and rapid gastric decontamination with activated charcoal are crucial. An acute dose of about 0.8 mg/kg of colchicine is presumed to be fatal. We report the clinical outcomes of two different cases of colchicine intoxication for attempted suicide. The dose required for morbidity or mortality varies significantly. The dose of 1 mg/kg in the first case was directly related with mortality, while the dose of 0.2 mg/kg in the second was related with survival. The other difference between the patients was the time of arrival to hospital after ingestion. This period was 4 hours for case 1 and only 1, hour for case 2. The initiation of treatment later than 2 hours after ingestion of colchicine may significantly impair treatment because the absorption time for colchicine after oral administration is about 30–120 minutes. The rising lactate level and high anion gap metabolic acidosis in our patient (case 1) were attributed to lactic acidosis, so hemodialysis was performed, and the duration of hemodialysis was prolonged. Lactic acidosis in the first case was one of the reasons for mortality. The most important parameters which define the chance of survival are the dose of ingested drugs and the arrival time to hospital after ingestion. The patients must be monitored closely for lactic acidosis and the decision to start hemodialysis must be made promptly for patients who develop lactic acidosis.

Orally Administered Phosphatidic Acids and Lysophosphatidic Acids Ameliorate Aspirin-Induced Stomach Mucosal Injury in Mice

Recent investigations revealed that lysophosphatidic acid (LPA), a phospholipid with a growth factor-like activity, plays an important role in the integrity of the gastrointestinal tract epithelium. This paper attempts to clarify the effect of orally administered phosphatidic acid (PA) and LPA on aspirin-induced gastric lesions in mice. Phospholipids, a free fatty acid, a diacylglycerol and a triglyceride at 1 mM (5.7 μmol/kg body weight) or 0.1 mM were orally administered to mice 0.5 h before oral administration of aspirin (1.7 mmol/kg). The total length of lesions formed on the stomach wall was measured as a lesion index. Formation of LPA from PA in the mouse stomach was examined by in vitro (in stomach lavage fluid), ex vivo (in an isolated stomach) and in vivo (in the stomach of a living mouse) examinations of phospholipase activity. Palmitic acid, dioleoyl-glycerol, olive oil and lysophosphatidylcholine did not affect the aspirin-induced lesions. In contrast, phosphatidylcholine (1 mM), LPA (1 mM) and PA (0.1, 1 mM) significantly reduced the lesion index. Evidence for formation of LPA from PA in the stomach by gastric phospholipase A2 was obtained by in vitro, ex vivo and in vivo experiments. An LPA-specific receptor, LPA2, was found to be localized on the gastric surface-lining cells of mice. Pretreatment with PA-rich diets may prevent nonsteroidal anti-inflammatory drug-induced stomach ulcers.

Influence of gastric bypass surgery on hepatic gluconeogenesis in type 2 diabetic Goto Kakizaki rats

To investigate the influence and significance of gastric bypass surgery on hepatic gluconeogenesis in type 2 diabetic Goto Kakizaki(GK) rats. Forty GK rats were randomly divided into Roux-en-Y gastric bypass group(group A) and sham operation group(group B). Differences in glucose tolerance experiment(OGTT) at preoperative and postoperative 1, 2 and 4 weeks were compared and weight was recorded. Glycated hemoglobin levels were measured preoperatively and 4 weeks postoperatively. The animals were sacrificed 4 weeks after surgery and liver tissues were harvested to detect the relative expression of mRNA and protein of glucose 6 phosphatase(G-6-P) and phosphoenol pyruvate kinase(PEPCK) with RT-PCR and Western blot. Fasting blood glucose levels were 6.5, 4.9, and 4.7 mmol/L in group A, and were 10.3, 10.4, and 12.5 mmol/L in group B, and the differences between two groups were statistically significant(P<0.05). The blood glucose level at 2 h after stomach lavage were 8.3, 6.4 and 5.5 mmol/L in group A, and were 21.4, 23.8 and 24.7 mmol/L in group B at postoperative 1, 2, 4 weeks, and the differences between two groups were statistically significant(P<0.05). The glycosylated hemoglobin at postoperative 4 weeks was(6.8±1.0)%, significantly lower than that in group B[(7.9±0.8)%, P<0.05]. Hepatic G-6-P and PEPCK mRNA relative expression at postoperative 4 weeks was reduced by 21.0% and 25.9% respectively as compared to group B, and the protein expression reduced as well. Immunohistochemistry showed that hepatic glycogen sedimentary in group A increased significantly. The relative mRNA and protein level of key enzymes of hepatic gluconeogenesis are significantly decreased after Roux-en-Y gastric bypass surgery and hepatic gluconeogenesis is reduced, which may be a potential mechanism of the decrease of blood glucose.

Seed dispersal by fishes in tropical and temperate fresh waters: The growing evidence

Fruit-eating by fishes represents an ancient (perhaps Paleozoic) interaction increasingly regarded as important for seed dispersal (ichthyochory) in tropical and temperate ecosystems. Most of the more than 275 known frugivorous species belong to the mainly Neotropical Characiformes (pacus, piranhas) and Siluriformes (catfishes), but cypriniforms (carps, minnows) are more important in the Holarctic and Indomalayan regions. Frugivores are among the most abundant fishes in Neotropical floodplains where they eat the fruits of a wide variety of trees and shrubs. By consuming fruits, fishes gain access to rich sources of carbohydrates, lipids and proteins and act as either seed predators or seed dispersers. With their often high mobility, large size, and great longevity, fruit-eating fishes can play important roles as seed dispersers and exert strong influences on local plant-recruitment dynamics and regional biodiversity. Recent feeding experiments focused on seed traits after gut passage support the idea that fishes are major seed dispersers in floodplain and riparian forests. Overfishing, damming, deforestation and logging potentially diminish ichthyochory and require immediate attention to ameliorate their effects. Much exciting work remains in terms of fish and plant adaptations to ichthyochory, dispersal regimes involving fishes in different ecosystems, and increased use of nondestructive methods such as stomach lavage, stable isotopes, genetic analyses and radio transmitters to determine fish diets and movements.

Effectivity of current sterility methods for transgastric NOTES procedures: results of a randomized porcine study

Natural-orifice transluminal endoscopic surgery (NOTES) is an emerging transluminal technique in which interventions are carried out by entering the abdominal cavity via a natural orifice such as the stomach. Infection is a potential risk of the procedure, and the potential pathogens are different from those encountered with skin incisions. Currently, available data regarding prophylactic anti-infective treatment are limited. We compared the effectiveness of topical antimicrobial lavage of mouth and stomach and proton pump inhibitor therapy with gastric cleansing with sterile saline solution in preventing NOTES-related contamination and infection. A randomized survival swine study was performed. Eight pigs underwent preparation with intravenously administered proton pump inhibitors, mouth and gastric lavage (chlorhexidine), and gastric irrigation (diluted neomycin), plus single-shot intravenous antibiotics. Control group (n = 8) underwent gastric cleansing with sterile saline solution. Peritoneal biopsy, multiple smears, and dilutions for cultures were taken and incubated. The swine were sacrificed after 14 days. Bacterial load was expressed in colony-forming units (CFU). One pig died due to gallbladder perforation after 3 days, 2/15 swine presented minor clinical signs of infection in the 14-day follow-up (all 3 pigs were in the control group). Mean C-reactive protein levels were 5.7 +/- 2.4 g/dL (therapy group) and 12.2 +/- 3.8 g/dL (control) ( P = 0.17). Bacterial growth was seen in 1/8 swine (therapy group) and 6/8 swine (control group) ( P = 0.002). Bacterial load was 282 CFU/mL (therapy) vs. 3.2 x 10 (5) CFU/mL (control) ( P = 0.023) in the follow-up. The use of intravenous antibiotics in addition to topical antimicrobial lavage of mouth and stomach and treatment with proton pump inhibitors decreased the peritoneal bacterial load to almost zero and this was associated with a significantly lower peritoneal infection rate compared with saline-only lavage.

Clinical efficacy and nursing of hemoperfusion (HP) in the treatment of patients with severe organic phosphorus pesticide poisoning

Objective To discuss the clinical efficacy and nursing methods of hemoperfusion (HP) in the treatment of severe organic phosphorus pesticide poisoning (AOPP). Methods 48 cases of severe organic phosphorus pesfcide poisoning were randomly divided into the conventional therapy group (22 cases) and the blood perfasion group (26 cases). The conventional therapy group received stomach lavage, liquid supplement, diuresis, catharsis, and drug therapies of atropine and pralidoxime. The bemoperfusion group received the treatment of blood perfusion for 1 ～ 3 times on the basis of the conventional treatments and the corresponding observation and nursing. Results The time of coma to sober and the hospitalization time were shorter, the total amount of atropine was less and the cure rate was higher in the hemoperfusion group compared to those in the conventional therapy group (P < 0.05). Conclusions The hemoperfusion in combination with conventional medical treatments is the most effective way to rescue severe organic phosphorus pesticide poisoning. The corresponding nursing should be given to the patients during the therapy. Key words: Hemoperfusion; Organic phosphorus pesticide; Poisoning; Emergency nursing

A Preliminary Investigation of Suicidality in Psychiatrically Hospitalized Veterans with Traumatic Brain Injury

The objective of this study was to explore suicidal behaviors documented at time of discharge from acute psychiatric hospitalization. Data from 114 acute psychiatric admissions were reviewed for 22 veterans with a history of traumatic brain injury (TBI). Information extracted included presence of suicidal ideation, nature of suicide attempts, and TBI characteristics. The Lethality of Suicide Attempt Rating Scale was used to classify veterans' non-lethal self-harm behavior. Post-TBI, 6 patients (27.3%) made a total of 14 suicide attempts. Half of those attempts required wounds being sutured, stomach lavage, or other medical attention. Clinicians and researchers are strongly encouraged to focus increased attention on suicide prevention in those with a history of TBI.

A Comparison of Immature Green Turtle (Chelonia mydas) Diets among Seven Sites in the Main Hawaiian Islands1

Understanding resource acquisition and feeding ecology of threatened species is integral to their conservation because diet is intimately linked with growth rate and reproductive output. We examined diets of immature green sea turtles, Chelonia mydas (L.), from seven sites on the islands of Hawai‘i, O‘ahu, Moloka‘i, and Lāna‘i in January and August 2003. Diet analysis was based on 191 samples collected from 181 live green turtles by stomach lavage. These samples were identified and quantified using dissection microscopy and the principles of microstereology. Diet of green turtles in the Main Hawaiian Islands was dominated by red algae, and diet items most commonly encountered were Acanthophora spicifera (an introduced species), Hypnea sp., Pterocladiella sp., and Cladophora sp. Sea grasses (Halophila hawaiiana and H. decipiens) were an important component of diet in turtles from Kāne‘ohe Bay. Content of green turtle diets differed among foraging grounds, and these differences may provide an insight into previously documented differences in turtle growth rates among sites.

Metamizol - akute Überdosierung in suizidaler Absicht

An 18-year-old girl swallowed 98 tablets of Novalgin (corresponding to 49 g metamizole) with suicidal intent. After stomach lavage she received forced diuresis for 14 hours. Metamizole metabolites in serum and urine were measured by thin-layer chromatography. After 24 hours the serum concentration of metamizole metabolites was still clearly elevated. Renal elimination amounted to 11 g metamizole. The patient survived the severe overdosage without significant organ abnormalities. This favourable course differs from reports of lethal intoxication with other pyrazolone derivatives, especially those with metamizole combination drugs. The forced diuresis proved to be a satisfactory elimination procedure. Biotransformation and elimination of the metamizole metabolites still continued after 24 hours.

Clinical outcomes in children with hyoscyamus niger intoxication no receiving physostigmine therapy

Diagnosis of hyoscyamus niger intoxication is based on clinical symptomatology and history. Therapy includes stomach lavage, supportive therapy, and physostigmine as a specific antidote. Physostigmine is not available in Turkey. This retrospective study investigated the clinical outcomes in children with hyoscyamus niger intoxication who did not receive physostigmine therapy. Twenty-three children whose history and medical records indicated hyoscyamus niger intoxication were included the study. None of the cases had any abnormal laboratory findings. All the patients were performed gastric lavage and provided with supportive therapy. None of the children had any complications, and none required mechanical ventilation or died. All the patients were discharged in good health within 48 h. Our findings suggest that hyoscyamus niger intoxication in children is self-terminating and responds to supportive therapy and that routine use of physostigmine is unnecessary in every case with hyoscyamus niger intoxication.

Lead Toxicosis in Falcons: A Method for Lead Retrieval

Abstract Lead toxicity is the most common heavy metal toxicosis in free-living birds, and one of the most important diseases of toxic origin in captive avian species. Falcons commonly ingest lead pellets or lead fragments concealed in the body of shot prey. Treatment of heavy metal toxicosis is an integral part of avian emergency and critical care practice. The primary treatment for lead toxicosis consists of the retrieval of lead particles from the digestive tract, and the secondary treatment consists of the use of chelating agents and support therapy. Lead retrieval from falcons with lead toxicosis should be undertaken immediately after the metallic radiodense particles have been observed in the gastrointestinal tract on survey radiographs. Lead pellets and lead fragments are retrieved using a combination of stomach lavage, rigid or flexible endoscopy, and long biopsy forceps.

Experimental study of blood lead kinetics in estuarine crocodiles (Crocodylus porosus) exposed to ingested lead shot.

A previous study of lead (Pb) contamination in estuarine crocodiles (Crocodylus porosus) in Kakadu National Park, Australia, found elevated Pb levels in bone and flesh from individuals caught in habitats where hunting with lead ammunition had occurred. Lead shot was suspected as the potential source of Pb in these animals. An investigation was designed to determine if crocodiles are capable of retaining and dissolving lead shot in their stomachs and absorbing the ionic Pb into the blood. Four of the six juvenile crocodiles (C. porosus) used in the experiment were fed an initial dose of five or ten lead shot each. Most of the lead shot were retained in the stomach over the 20-week experimental period, as confirmed by stomach lavage and radiography of the stomach region. From 13 to 30% of the original weight of individual lead shot had been eroded in that time. In vitro experiments confirmed that lead shot could be dissolved under conditions simulating those known for the crocodilian stomach. Blood Pb concentrations increased by an order of magnitude within a week after dosing three crocodiles with five lead shot each, and then attained steady-state equilibrium 5-20 weeks after dosing, with blood Pb steady-state levels ranging from 278 to 363 microg/dL. The blood Pb concentration-time curves in these crocodiles followed a one-compartment model with first-order loss kinetics that yielded an apparent biological half-life for Pb in blood of about 3.4 days. Throughout the experiment, the crocodiles remained in apparent good physical condition and displayed no clinical signs of Pb toxicosis. These observations, together with the very high blood Pb levels that were sustained for several months, suggest that crocodilians may possess a relatively high degree of resistance to Pb toxicity.

Diagnosis of subclinical cryptosporidiosis in captive snakes based on stomach lavage and cloacal sampling

The applicability of stomach lavage and cloacal swab techniques for diagnosis of subclinical cryptosporidiosis were tested in eight captive snakes subclinically infected with Cryptosporidium serpentis. Two feeding regimes were employed. The snakes were first fed 7 days prior to stomach and cloaca sampling, and then 3 days prior to sampling, and the oocysts were detected by fluorescein labeled monoclonal antibody (mAb) and by acid-fast stained (AFS) direct wet smear (DWS). The overall sensitivity of AFS DWS was 95% for stomach samples and 57% for cloacal samples, with false-negativity of 5% and 43%, respectively. A significant relationship ( P<0.01) was found between stomach and cloacal samples when mAb were used for oocyst detection. Stomach sampling was diagnostically superior to cloacal sampling for identifying snake subclinical cryptosporidiosis. Based on gastric aspirates, cryptosporidial infection was diagnosed in all eight animals, and only in two or four snakes when cloacal swab material was processed by AFS or by mAb, respectively. Feeding snakes 3 days prior to sampling facilitated diagnosis based on stomach samples; however, it did not improve diagnosis when cloacal samples were used. The fraction of oocyst-positive stomach samples was significantly higher ( P<0.05) for snakes fed 3 days prior to gastric lavage when compared with the fraction of positive samples of snakes fed 7 days prior to lavage. If subclinical cryptosporidiosis is suspected in a non-eating snake patient, force-feeding and stomach lavage, 3 days after the meal, is recommended.

Biochemical and mutational analysis of the histidine residues of staphylococcal enterotoxin A.

The goal of this study was to examine the role of histidine residues in the biological activities of staphylococcal enterotoxin A (SEA). Carboxymethylated SEA was unable to stimulate murine T-cell proliferation but was resistant to monkey stomach lavage fluid degradation, suggesting that native conformation was intact. Site-directed mutagenesis of the histidine residues of SEA was subsequently performed. SEA-H44A (SEA with histidine 44 replaced with alanine), SEA-H44D, SEA-H50A, SEA-H50D, SEA-H114A, SEA-H114D, SEA-H187A, and SEA-H187D retained superantigen and emetic activities, whereas SEA-H225A and SEA-H225D were defective in the ability to stimulate T-cell proliferation. These mutants were unable to compete with SEA for binding to Raji cells, suggesting that the defect in SEA-H225A and SEA-H225D is due to impaired major histocompatibility complex class II binding. SEA-H225D provoked an emetic response in monkeys only if fed at high doses, while SEA-H225A did not provoke an emetic response at low or high doses. In comparison, SEA-H61A and SEA-H61D were defective in emetic activity but not in the ability to stimulate murine T-cell proliferation. Overall, these studies show that the carboxy-terminal histidine at residue position 225 of SEA is important for both the superantigen and emetic activities of this enterotoxin. Histidine 61 appears to be important for emetic activity but not for superantigen activity, consistent with the hypothesis that the two activities are separable in staphylococcal enterotoxins.