Histopathological observations on the activity of diclazuril (Vecoxan) against the endogenous stages of Eimeria crandallis in sheep

Doses of sporulated oocysts of Eimeria crandallis were administered to 60 housed lambs aged 3-4 weeks that had been raised coccidia-free. Thirty of the lambs were medicated with diclazuril at intervals over a 20-day period post-infection with the remaining lambs serving as untreated controls. Lambs were euthanased between 5 and 22 days post-infection (dpi) and sections of the small intestine and caecum examined histologically. Untreated lambs showed loss of surface epithelial cells and villous atrophy associated with first-generation meronts, crypt destruction and crypt hyperplasia associated with pro-gamont stages. Diclazuril appeared to have a direct effect on several stages of the parasite life cycle, in particular, the large first-generation meront. Indications were that the drug also had an effect on second-generation meronts and gamont stages. Therapeutic benefits of diclazuril treatment appeared greatest when given early in the infection before damage to the intestine occurs although removal of coccidial stages did appear to reduce the pathology of the disease.

A physiological and biochemical model for digestion in the ectoparasitic mite, Psoroptes ovis (Acari: Psoroptidae)

Mites are an important group of arthropod pests affecting crops, animals and humans. Despite this, detailed physiological studies on these organisms remain sparse due largely to their small size. Unifying models are required to draw together the diverse information from studies on different groups and species. This paper describes a model for digestion in the parasitic mite, Psoroptes ovis, the causative agent of psoroptic mange or sheep scab disease. The limited information about this species is supplemented with data from other acarines, especially house dust mites and ticks. We review the range of enzymes and allergens found in mites and consider their possible roles in digestion in mites, generally and in particular, P. ovis. Histological studies, enzyme biochemistry and molecular biology and experimental evidence suggest that P. ovis utilises a digestive system reliant upon acid peptidases functioning in a largely intracellular environment. The actions of the digestive enzymes are supplemented by the involvement of bacteria as potential direct and indirect sources of nutrition. It is possible that some extra-corporeal digestion also takes place. The interaction of bacteria and digestive enzymes on the skin surface of the sheep may be responsible for the excessive pathological reactions evident in clinical sheep scab.

Temporal pattern of isotype-specific antibody responses in primary and challenge infestations of sheep with Psoroptes ovis--the sheep scab mite

In sheep Psoroptes ovis provokes an allergic dermatitis with significant P. ovis antigen-specific IgE responses. The kinetics of the IgE response to primary and challenge infestations of P. ovis were reported earlier [Parasite Immunol. 22 (2000) 407]. The present study examines IgG, IgM and IgA responses to primary and challenge infestations of P. ovis and the profile of antigens/allergens reacting with IgG and IgE antibodies. Antigen-specific enzyme-linked immunosorbent assays (ELISAs) demonstrate that primary infestations elicited significant increases in levels of IgG and IgM but not IgA antibodies. IgG and IgM responses to primary and challenge infestations were not significantly different. Western blots of reduced P. ovis proteins indicate that IgG antibodies reacted with five major antigens following primary infestation and only three of these after challenge infestation. IgE antibodies bound to three major and five minor allergens after primary infestation and two additional minor allergens after challenge infestation. Immunodominant antigens >100 and <15 kDa and allergens >100 kDa were most consistent in stimulating substantial IgG and IgE antibody responses, respectively. These antigens/allergens may be exploited in immunodiagnosis and modulation of the host immune response.

Defining and reporting diarrhoea during enteral tube feeding: do health professionals agree?

INTRODUCTION

The criteria used to define diarrhoea during enteral tube feeding (ETF) and the interrater reliability of nursing staff reporting it in clinical practice has not been investigated.

METHODS

A structured questionnaire was sent to a cohort of dietitians, specialist stroke nurses, intensive therapy unit (ITU) nurses and consultant gastroenterologists regarding their criteria for defining ETF diarrhoea. In a clinical study, nursing staff independently inspected faeces from patients receiving ETF and were asked whether they considered the patient to have diarrhoea.

RESULTS

Thirty-five healthcare workers responded to the questionnaire. Faecal frequency, faecal consistency and faecal quantity were all considered important criteria in defining ETF diarrhoea. Faecal frequency was considered more important than consistency and quantity (P = 0.048), although not all professional groups agreed on the order of importance. In the clinical study, nursing staff agreed on the presence or absence of diarrhoea on 75% of occasions, with agreement being only fairly reliable (kappa = 0.48).

CONCLUSION

Healthcare workers use a range of criteria to define ETF diarrhoea, but may not agree on the importance of each criteria. In order to prevent confusion between professional groups, healthcare workers should be encouraged to describe faecal characteristics rather than rely on the term 'diarrhoea'.

The effects of stage-specific selection on the development of benzimidazole resistance in Haemonchus contortus in sheep

Resistance to the benzimidazole (BDZ) class of anthelmintics in nematodes of sheep has become a common and global phenomenon. The rate at which the selection process and development of resistance occurs is influenced by a number of factors. Of these, the effects of stage-specific exposures to anthelmintic were investigated with a BDZ-resistant strain of Haemonchus contortus (HCR) over five parasite generations. Sheep were infected at each generation with the HCR strain and were treated with thiabendazole (TBZ), either 5 days post-infection (p.i.) (larval line), 21 days p.i. (adult line), or left untreated (no selection line). Additionally eggs from each generation were exposed to TBZ (egg line). Geometric worm burdens were calculated from post-mortem worm counts, both at the start of the study, and after the final selection studies for each of the selection lines. Egg hatch assays (EHAs) were also conducted throughout the study. All data relating to worm burdens and EHAs for each generation were analysed by linear regression to produce dose titration curves and lethal dose(50) (LD(50)) values for each of the selection lines. Over the five generations, LD(50) values on dose-response were increased and worm survival occurred at higher dose rates of TBZ irrespective of the parasite stage exposed to treatment. A similar picture was seen with ED(50) values, which showed a fluctuating but generally upward trend for each of the three selection lines. In contrast, LD(50) and ED(50) values were decreased in the no selection line, indicating some degree of reversion albeit to levels still considered to be BDZ-resistant.

Attempts to immunize sheep against the scab mite, Psoroptes ovis

Adult Psoroptes ovis were successively extracted in saline, 1% Tween, 1% Triton and 8 m urea +0.1% CHAPS. The Triton extract was separated into fractions which did or did not bind to ConA lectin. Using QuilA as adjuvant, both Triton fractions and the saline, Tween and urea extracts were tested separately as candidate protective antigens against a P. ovis challenge infestation in sheep. All induced circulating antibody responses, but the saline and Tween extracts also stimulated significant protective effects in those sheep which developed active disease. Compared to control sheep injected with adjuvant only, these immunized animals had more than two and seven-fold reductions in mean lesion areas and mite numbers, respectively.

The many varieties of catatonia

About 10% of patients with severe acute psychiatric illness exhibit a cluster of motor signs (mutism, negativism, rigidity, posturing, stereotypy, staring, etc.) that are identified as the syndrome of catatonia. Catatonia responds to sedative anticonvulsant treatment (barbiturates, benzodiazepines) and to electroconvulsive therapy. These treatments raise seizure thresholds. The commonality in response indicates that catatonia, malignant catatonia, neuroleptic malignant syndrome, toxic serotonin syndrome, delirious mania, catatonic excitement, benign stupor, and oneirophrenia are best evaluated as diverse manifestations of one syndrome for clinical and neuroscience research purposes.

Use of a high-fidelity simulator to develop testing of the technical performance of novice anaesthetists

BACKGROUND

We used the Delphi technique to gain a consensus from 26 consultant anaesthetists about technical tasks during general anaesthesia. We then developed a technical scoring system to assess anaesthetists undertaking general anaesthesia with rapid sequence induction.

METHODS

We then followed the performance of six novice anaesthetists on five occasions during their first 3 months of training. At each, visit each novice 'anaesthetized' the Human Patient Simulator at Bristol Medical Simulator Centre. For comparison seven post-fellowship anaesthetists were scored on one occasion.

RESULTS

Novice scores improved significantly over the 12-week period (P<0.01). A significant difference was also found between the final novice scores and the post-fellowship subjects (P<0.05).

CONCLUSIONS

These findings suggest that simulation can be used to observe and quantify technical performance.

Anthelmintic resistance detection methods

The development of species and populations of parasitic helminths with resistance to one or more anthelmintics is an increasing problem world-wide. The majority of currently available anthelmintics used to control parasitic nematodes of cattle and sheep belong to only three main groups, the benzimidazoles, imidazothiazoles and the avermectins/milbemycins. The successful implementation of helminth control programmes designed to limit the development of resistance in nematode populations depends to some degree on the availability of effective and sensitive methods for its detection and monitoring. A variety of in vivo and in vitro tests have been developed for the detection of nematode populations resistant to the main anthelmintic groups, but each suffers to some degree from reliability, reproducibility, sensitivity and ease of interpretation. This review covers those tests that have been reported and described and highlights some of their strengths and weaknesses.

The role of probiotics and prebiotics in the management of diarrhoea associated with enteral tube feeding

INTRODUCTION

Diarrhoea is a common and serious complication of enteral tube feeding, and has a range of aetiologies. Manipulation of the colonic microflora may reduce the incidence of enteral tube feeding diarrhoea via suppression of enteropathogens and production of short-chain fatty acids. Probiotics and prebiotics are commonly used during enteral tube feeding to manipulate the colonic microflora; however, their efficacy is as yet uncertain.

METHODS

English-language studies investigating the pathogenesis of enteral tube feeding diarrhoea and the use of probiotics and prebiotics were identified by searching the electronic databases CINAHL, EMBASE and MEDLINE from 1980 to 2001. The bibliographies of articles obtained were searched manually.

RESULTS

Only two prospective, randomized, double-blind, placebo-controlled trials have investigated the effect of a probiotic on enteral tube feeding diarrhoea; however, results are conflicting. No prospective, randomized, double-blind, placebo-controlled studies have specifically addressed the effect of a prebiotic on the incidence of enteral tube feeding diarrhoea.

CONCLUSION

Theoretically, probiotics and prebiotics may be of benefit in prophylaxis against enteral tube feeding diarrhoea; however, there is currently insufficient evidence to support their routine use. Prospective, randomised, double-blind, placebo-controlled studies investigating their effect on diarrhoea are required. These observations are discussed with reference to the current literature.

Inhibition of the death receptor pathway by cFLIP confers partial engraftment of MHC class I-deficient stem cells and reduces tumor clearance in perforin-deficient mice

NK cells mediate acute rejection of MHC class I-deficient bone marrow cell (BMC) grafts. However, the exact cytotoxic mechanisms of NK cells during acute BMC graft rejection are not well defined. Although the granule exocytosis pathway plays a major role in NK cell-mediated rejection, alternative perforin-independent mechanisms also exist. By analyzing the anti-apoptotic effects of cellular Fas-associated death domain-like IL-1-converting enzyme-inhibitory protein (cFLIP) overexpression, we investigated the possible role of death receptor-induced apoptosis in NK cell-mediated cytotoxicity. In the absence of perforin, we found that cFLIP overexpression reduces lysis of tumor cells by NK cells in vitro and in vivo. In addition, perforin-deficient NK cells were impaired in their ability to acutely reject cFLIP-overexpressing TAP-1 knockout stem cells. These results emphasize the importance of NK cell death receptor-mediated killing during BMC grafts in the absence of perforin.

Placebo expectancy effects in the relationship between glucose and cognition

The present study investigated the extent of expectancy in the ability of glucose to affect cognitive performance. Using a within-subjects design, subjects (n 26) completed four experimental sessions (in counterbalanced order and after an initial practice session) during which they were given a 500 ml drink 30 min prior to completing a cognitive assessment battery. In addition, all subjects completed a baseline practice session during which they were given no drink. During two of the sessions, subjects were given a drink containing 50 g glucose and on the other two they were given a drink containing aspartame. A balanced placebo design was used, such that for half the sessions subjects were accurately informed as to the content of the drink (glucose or aspartame), whereas in the other two sessions they were misinformed as to the content of the drink. The task battery comprised a 6 min visual analogue of the Bakan vigilance task, an immediate verbal free-recall task, an immediate verbal recognition memory task and a measure of motor speed (two-finger tapping). Blood glucose and self-reported mood were also recorded at several time points during each session. Glucose administration was found to improve recognition memory times, in direct contrast to previous findings in the literature. Glucose administration also improved performance on the Bakan task (relative to the control drink), but only in sessions where subjects were informed that they would receive glucose and not when they were told that they would receive aspartame. There were no effects either of the nature of the drink or expectancy on the other measures. These results are interpreted in terms of there being some contribution of expectancy concerning the positive effects of glucose on cognition in studies which have not used an equi-sweet dose of aspartame as a control drink.

1-(Arylpiperazinylamidoalkyl)-pyrimidones: orally active inhibitors of lipoprotein-associated phospholipase A(2)

The lipophilic 1-substituent in a series of 1-((amidolinked)-alkyl)-pyrimidones, inhibitors of recombinant lipoprotein-associated phospholipase A(2), has been modified to give inhibitors of high potency in human plasma and enhanced physicochemical properties. Phenylpiperazineacetamide derivative 23 shows very promising oral activity.

Culture age and drying time as variables of the AOAC Sporicidal Test

In the United States, the AOAC Sporicidal Activity of Disinfectants Method 966.04 is the standard for identifying a liquid chemical germicide as a sterilant. Furthermore, the highest level of a disinfectant must also be a sterilant as defined by Method 966.04, when used in its sterilant mode for a longer exposure time. The AOAC Sporicidal Test is also used as a part of the standard test methods to define a sterilant for Australia and the European Union. Many laboratories have identified variables of this test that can affect the sterilization exposure time for sterilants, or even the ability to classify a chemical as a sterilant. Method 966.04 requires spore-labeled porcelain penicylinders (cylinders) and silk suture loops, collectively referred to as carriers, to be dried for 24 h, but allows these carriers to be used for at least 7 days, in effect allowing a drying time of 24 h to at least 7 days. We tested the resistance of cylinders that had been labeled with Bacillus subtilis spores cultured for 72, 96, and 120 h, and dried for 24, 48, and 72 h against a 60 min exposure to 2.0% alkaline glutaraldehyde, and 2, 5, 10, 15, and 20 min exposures to 2.5N HCl. All the culture incubation and drying times met the standard of resistance to 2.5N HCI for at least 2.0 min at 20 degrees C, and all carriers contained at least 10(5) colony-forming units (CFU) of B. subtilis per carrier. However, for 3 repeated tests, regardless of incubation time, an average of 96% of the carriers were sterilized by the 2.0% glutaraldehyde after drying for 24 h, and an average of 61 % were sterilized after drying for 48 or 72 h. We propose that the variable of drying time be eliminated from Method 966.04.

Copy-DNA cloning and characterisation of a potato alpha-glucosidase: expression in Escherichia coli and effects of down-regulation in transgenic potato

Polymerase chain reaction-based methodology was used to obtain a cDNA clone (MAL2) from potato (Solanum tuberosum L.) with the sequence characteristics of an alpha-glucosidase. Phylogenetic analysis of the deduced polypeptide encoded by this cDNA demonstrated that the most similar sequences were alpha-glucosidases and alpha-xylosidases of plant origin. The MAL2 cDNA was expressed in Escherichia coli and the recombinant MAL2 protein was affinity-purified. MAL2 catalysed the hydrolysis of a range of maltooligomers and p-nitrophenyl-alpha-D-glucopyranoside with a pH optimum of 5.5-5.7. The substrate with the lowest Km value was maltotetraose (3.7 mM). The MAL2 expression product did not catalyse the hydrolysis of xyloglucan oligosaccharides, p-nitrophenyl-alpha-D-xylopyranoside or gelatinised potato starch. MAL2 was down-regulated in transgenic potato plants using an antisense approach. In several independent transgenic antisense lines, MAL2 expression was severely down-regulated. Despite this, no decrease in total extractable alpha-glucosidase and alpha-xylosidase activity could be detected in tissues from the transgenic plants. In glasshouse trials, no visible phenotype, change in tuber yield or carbohydrate content was associated with MAL2 down-regulation. The implications of these results are discussed.

Recent Developments in Ectoparasiticides

The sales and use of ectoparasiticides for the control of arthropod parasites of domestic animals constitute a major sector of the global animal health market. Animals are infected by a number of parasitic insect and acarine species causing major economic losses in production livestock, intense irritation and skin disease in companion animals, or public health issues, including bites of humans or zoonotic disease transmission. Dog and cat fleas, for example, can be a serious source of both animal and human irritation, which has led to a rapid expansion in the development of flea control products. The control of ectoparasite infections of veterinary importance still relies heavily on the use of chemicals that target the arthropod nervous system. Such compounds have suffered from a number of drawbacks, including the development of resistance and concerns over human and environmental safety. The search for safer technologies has, however, been hindered by the limited number of active target sites present in arthropods and, to some degree, by the ever-increasing costs of research and development of compounds with novel modes of action.This review provides a background to the currently available groups of ectoparasiticide compounds used in veterinary medicine and highlights some of the more recent developments including the introduction of insect growth regulators and new and improved methods of product application.

Compared with nibbling, neither gorging nor a morning fast affect short-term energy balance in obese patients in a chamber calorimeter

OBJECTIVE

To test if a diet of 4.2 MJ/24 h as six isocaloric meals would result in a lower subsequent energy intake, or greater energy output than (a) 4.2 MJ/24 h as two isocaloric meals or (b) a morning fast followed by free access to food.

DESIGN

Subjects were confined to the Metabolic Unit from 19:00 h on day 1 to 09:30 h on day 6. Each day they had a fixed diet providing 4.2 MJ with three pairs of meal patterns which were offered in random sequence. They were: six meals vs two meals without access to additional foods (6vs2), or six meals vs 2 meals with access to additional food (6+vs2+), or six meals vs four meals (6+vsAMFAST). In the AMFAST condition the first two meals of the day were omitted to reduce daily intake to 2.8 MJ and to create a morning fast, but additional food was accessible thereafter. Patients were confined in the chamber calorimeter from 19:00 h on day 2 until 09:00 h on day 4, and then from 19:00 h on day 4 to 09:00 h on day 6. The order in which each meal pattern was offered was balanced over time.

MEASUREMENTS

Energy expenditure (chamber calorimetry), spontaneous activity (video) and energy intake (where additional foods were available) during the final 24 h of each dietary component.

SUBJECTS

Ten (6vs2), eight (6+vs2+) and eight (6+vsAMFAST) women were recruited who had a BMI of greater than 25 kg/m2.

RESULTS

From experiment 6vs2 the difference between energy expenditure with six meals (10.00 MJ) and two meals (9.96 MJ) was not significant (P=0.88). Energy expenditure between 23:00 h and 08:00 h ('night') was, however, significantly higher (P=0.02) with two meals (9.12 MJ/24 h) compared with six meals (8.34 MJ/24 h). The pattern of spontaneous physical activity did not differ significantly between these two meal patterns (P>0.05). Total energy intake was affected by neither meal frequency in experiment 6+vs2+ (10.75 MJ with six, 11.08 MJ with two; P=0.58) nor a morning fast in experiment 6+vsAMFAST (8.55 MJ/24 h with six, 7.60 MJ with AMFAST; P=0.40). The total diet of subjects who had a morning fast tended to have a lower percentage of total energy from carbohydrate (40%) than when they had six meals per 24 h (49%) (P=0.05). Subsequent energy balance was affected by neither meal frequency (6vs2; P=0.88, 6+vs2+; P=0.50) nor a morning fast (P=0.18).

CONCLUSIONS

In the short term, meal frequency and a period of fasting have no major impact on energy intake or expenditure but energy expenditure is delayed with a lower meal frequency compared with a higher meal frequency. This might be attributed to the thermogenic effect of food continuing into the night when a later, larger meal is given. A morning fast resulted in a diet which tended to have a lower percentage of energy from carbohydrate than with no fast.