Assessing the impact of tailored biosecurity advice on farmer behaviour and pathogen presence in beef herds in England and Wales.

The term 'biosecurity' encompasses many measures farmers can take to reduce the risk of pathogen incursion or spread. As the best strategy will vary between settings, veterinarians play an important role in assessing risk and providing advice, but effectiveness requires farmer acceptance and implementation. The aim of this study was to assess the effectiveness of specifically-tailored biosecurity advice packages in reducing endemic pathogen presence on UK beef suckler farms. One hundred and sixteen farms recruited by 10 veterinary practices were followed for three years. Farms were randomly allocated to intervention (receiving specifically-tailored advice, with veterinarians and farmers collaborating to develop an improved biosecurity strategy) or control (receiving general advice) groups. A spreadsheet-based tool was used annually to attribute a score to each farm reflecting risk of entry or spread of bovine viral diarrhoea virus (BVDV), bovine herpesvirus-1 (BHV1), Mycobacterium avium subsp. paratuberculosis (MAP), Leptospira interrogans serovar hardjo (L. hardjo) and Mycobacterium bovis (M. bovis). Objectives of these analyses were to identify evidence of reduction in risk behaviours during the study, as well as evidence of reductions in pathogen presence, as indications of effectiveness. Risk behaviours and pathogen prevalences were examined across study years, and on intervention compared with control farms, using descriptive statistics and multilevel regression. There were significant reductions in risk scores for all five pathogens, regardless of intervention status, in every study year compared with the outset. Animals on intervention farms were significantly less likely than those on control farms to be seropositive for BVDV in years 2 and 3 and for L. hardjo in year 3 of the study. Variations by study year in animal-level odds of seropositivity to BHV1 or MAP were not associated with farm intervention status. All farms had significantly reduced odds of BHV1 seropositivity in year 2 than at the outset. Variations in farm-level MAP seropositivity were not associated with intervention status. There were increased odds of M. bovis on intervention farms compared with control farms at the end of the study. Results suggest a structured annual risk assessment process, conducted as a collaboration between veterinarian and farmer, is valuable in encouraging improved biosecurity practices. There were some indications, but not conclusive evidence, that tailored biosecurity advice packages have potential to reduce pathogen presence. These findings will inform development of a collaborative approach to biosecurity between veterinarians and farmers, including adoption of cost-effective strategies effective across pathogens.

Foot-and-mouth disease: the question of implementing vaccinal control during an epidemic.

The question of whether or not to use vaccines during an epidemic of foot-and-mouth disease (FMD) has interested veterinary administrators for many decades. This review assesses the historical uses, successes and failures of vaccinal control, and addresses the questions of where, how, and when to use vaccination against FMD. Approaching the problem in this manner can aid in identifying which tools are likely to be most effective during an epidemic, and how successful a given contingency plan might be. The infection status (endemic, semi-endemic, disease-free) of a region has historically mapped where global vaccination has been implemented according to the generality: endemic>semi-endemic>disease-free. More specifically, biomodels and cost-benefit analyses can indicate when vaccination should be implemented for optimal disease control. Finally, numerous local epidemiological factors will provide useful insights into how vaccinal controls can be used effectively.

The effects of Arcanobacterium pyogenes on endometrial function in vitro, and on uterine and ovarian function in vivo.

Uterine bacterial infection after parturition causes endometritis, perturbs ovarian function and leads to infertility in cattle. Although endometritis is caused by mixed infections, endometrial pathology is associated with the presence of Arcanobacterium pyogenes. The aims of the present study were to determine the effects of A. pyogenes on endometrial function in vitro, and on uterine and ovarian function in vivo. Heat-killed A. pyogenes did not affect the production of prostaglandin F2alpha (PGF) or prostaglandin E(2) (PGE) from endometrial explants, or purified populations of endometrial epithelial or stromal cells. However, the explants produced more PGF and PGE than controls when treated with a bacteria-free filtrate (BFF) cultured from A. pyogenes. Similarly, BFF stimulated PGF and PGE production by epithelial and stromal cells, respectively. So, BFF or control PBS was infused into the uterus of heifers (n=7 per group) for 8 days, starting the day after estrus. Emergence of the follicle wave, dominant follicle or corpus luteum diameter, and peripheral plasma FSH, LH, estradiol, progesterone, PGFM, or acute phase protein concentrations were unaffected by the BFF infusion. In the live animal it is likely that the intact uterine mucosa limits the exposure of the endometrial cells to the exotoxin of A. pyogenes, whereas the cells are readily exposed to the toxin in vitro.

The Mitrofanoff procedure: does it last?

OBJECTIVE: To examine the long-term effectiveness of the Mitrofanoff principle and establish if the catheterizing channel is sufficiently robust for long-term use. PATIENTS AND METHODS: Ten patients who had undergone Mitrofanoff reconstruction between 1989 and 1991 (minimum follow-up 10 years) were offered reinterview by one of the authors (J.F.), which involved a structured questionnaire assessing catheterization, continence and complications. RESULTS: One patient had died; nine patients were alive and eight agreed to the structured interview. All the patients had their original stoma and all were completely continent. Four of the patients had experienced stenosis, four had had stones and four had been ill with urinary tract infection(s). CONCLUSION: Despite the complications of infection, stones and some episodic stenosis, the Mitrofanoff channel remains functional for long periods without sustaining structural damage.

Binding of dihydroartemisinin to differentiating neuroblastoma cells and rat cortical homogenate.

The binding characteristics of dihydroartemisinin to neural tissues and cells in culture were studied by incubating differentiating C6 and NB2a cells and rat cerebral cortex homogenate with 1 to 200 microM 14C-labelled dihydroartemisinin with or without 2 microM haemin for 24 h. The role of protein thiol and amine groups in dihydroartemisinin binding was assessed by pre-incubation of the cortex homogenate with sodium cyanate and/or iodoacetamide. Rosenthal plots of binding data demonstrated that there were two discrete phases of dihydroartemisinin binding. Haemin increased the total binding of dihydroartemisinin to both cortex and cell proteins. In each preparation, haemin increased Bmax of the high affinity binding sites and also increased kD of NB2a high affinity binding sites and decreased kD of cortex low affinity binding sites. The effects of haemin on the binding parameters of cortex resembled its effects on C6 cells rather than NB2a cells. NB2a high and low affinity binding sites had a greater affinity for dihydroartemisinin than those of either rat cortex or C6 cells. Iodoacetamide and sodium cyanate reduced binding to cortex proteins by approximately 70%. Co-incubation of 14C-dihydroartemisinin with arteether reduced binding of dihydroartemisinin but co-incubation with desoxyartemisinin did not. These studies demonstrate that the known haemin-induced increase in toxicity of dihydroartemisinin to differentiating neuroblastoma cells is accompanied by a corresponding increase in dihydroartemisinin binding to cell proteins, that protein thiol and amine groups react with the products of the reaction between dihydroartemisinin and haemin and point to a relationship between the toxicity of artemisinin derivatives and protein binding.

Morphological and immunocytochemical effects of dihydroartemisinin on differentiating NB2a neuroblastoma cells.

The toxicity caused by the artemisinin derivative dihydroartemisinin in differentiated NB2a neuroblastoma cells was studied by transmission and scanning electron microscopy, Western blotting and immunocytochemistry. Western blotting with monoclonal antibodies failed to detect any specific changes in the cell cytoskeleton, nor were any changes detected by immunocytochemistry. This was consistent with electron microscopy of surviving cell neurites. Transmission electron microscopy revealed that dihydroartemisinin damaged NB2a cell mitochondrial cristae and endoplasmic reticulum. Scanning electron microscopy revealed that dihydroartemisinin depleted the filopodia-like processes projecting from the surface of the cell body and neurites. Some, or all, of these drug-induced changes in differentiating NB2a cells may have a role in the neurotoxicity of artemisinin derivatives.

The Malone antegrade colonic enema procedure: outcome and lessons of 6 years' experience.

The successful management of faecal incontinence can dramatically improve the quality of life of affected children. The introduction of the non-refluxing, catheterisable appendico-caecostomy provides the opportunity to treat previously resistant patients. Over a 6-year period, 29 children had a Malone antegrade continent stoma for enema administration (MACE). Incontinence was related to spina bifida in 12 children, ano-rectal anomaly in 12, Hirschprung's disease in 2, followed excision of a pelvic tumour in 2, and was secondary to intractable chronic constipation in 1. The conduit was fashioned from the appendix (20), a caecal tube (8), or a gastric tube (1). Surgical complications were stomal stenosis (11), wound infection (1), anastomotic leak (1), MACE stoma prolapse (1), and a pressure sore (1). Colonic irrigation was achieved with washouts of saline (24), saline plus phosphate (4), and saline plus Picolax (1). Twenty-three patients have complete control of bowel function, but 4 still soil. Two remain incontinent, 1 of whom is still being instructed. One child subsequently had a colostomy, but still uses the MACE stoma. Successful bowel management requires motivation, dedication, commitment, and the input of a clinical nurse specialist. The MACE is a relatively straightforward operative procedure that provides an effective washout technique that is acceptable to both parents and children.

Bladder washout and stone formation in paediatric enterocystoplasty.

OBJECTIVE: To review the incidence of stone formation in our patients with enterocystoplasty to determine the effect of regular bladder washout. METHODS: From 1988 to 1995, a prospective cohort of 30 children underwent enteroplasty with continent diversion. Over the same period, a consecutive group of 30 children had an augmentation alone. All were instructed to wash out their bladder on a weekly basis with sterile water. The frequency of the washouts increased if there were problems with increasing mucus production. Their incidence of stone formation has been compared to a similar group of 30 children performing clean intermittent self catheterisation (CISC) on their native bladders. RESULTS: Five (17%) children with continent diversions formed bladder stones (mean time to formation 35 months, range 13-59 months) were compared with 2 (7%) of children with augmentation. No child performing CISC alone formed stones. CONCLUSIONS: A regime of regular bladder washout in children with enterocystoplasty did not significantly reduce the incidence of stone formation when compared to previously published data.

Weight-based accuracy of parenteral nutrient solutions prepared with an automated compounder.

The accuracy of an automated compounder in preparing parenteral nutrient solutions was evaluated. A total of 480 1-, 2-, and 3--L solutions representing 68 different formulations, some containing electrolytes, were prepared with two Automix devices. The actual weight of the final product was compared with the calculated weight of all ingredients plus the weight of the empty final container. The weight of each ingredient was calculated by multiplying the specific gravity by the volume. A solution was considered acceptable if it weight 95% to 105% of the estimated weight. Only two bags were outside the acceptable range. The mean weight as a percentage of estimated weight for all bags was 100.07 +/- 1.26%. Of the 480 nutrient solutions prepared by an automated compounder, 478 were within 5% of their expected final weight.

Enhanced in vitro neurotoxicity of artemisinin derivatives in the presence of haemin.

The role of haem in the neurotoxicity of artemisinin derivatives has been studied in vitro by examining neurite outgrowth measured by image analysis and cellular metabolism of the tetrazolium salt MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) measured spectrophotometrically in the neuroblastoma cell line NB2a, and by examining binding of radiolabelled dihydroartemisinin to NB2a cell and rat brain proteins. In the cases of artemether, dihydroartemisinin, and arteether, haemin (ferriprotoporphyrin IX) significantly increased the dose-related inhibition of neurite outgrowth from differentiating NB2a cells and significantly increased the dose-dependent inhibition of MTT metabolism. Inhibition of neurite outgrowth and metabolism of MTT in the presence or absence of haemin ranged from 72% to 93% and from 27% to 49% at a drug concentration of 300 nM. Haemin also significantly increased the dose-related binding of radiolabelled dihydroartemisinin to proteins from NB2a cells approximately twofold and to rat brain between three- and sixfold. Haemin did not enhance the neurotoxicity of desoxyarteether, a structural analogue of arteether with an ether linkage in the place of the endoperoxide bridge. It is suggested that haemin may catalyse the transformation of these derivatives via an interaction with the endoperoxide bridge of the artemisinin derivative to produce free radicals or electrophilic intermediates that are toxic to neuronal cells.

The toxicity of artemisinin and related compounds on neuronal and glial cells in culture.

The antimalarial drug artemisinin and a number of its derivatives were tested for their effects on proliferation of undifferentiated neuroblastoma Nb2a cells and glioma C6 cells in culture as well as their ability to inhibit neurite outgrowth from Nb2a cells differentiated by removal of serum and addition of dibutyryl cyclic AMP. In the Nb2a and C6 cell cultures, all drugs except desoxyartemisinin significantly inhibited cell proliferation in a dose-related manner with the lowest effective concentration being that of artemisinin at 0.1 microM. Artemether, arteether, artemisinin and dihydroartemisinin also produced a dose-related decrease in the number of neurites/extensions formed by differentiating Nb2a cells, with an effect of dihydroartemisinin at a concentration as low as 1 nM. Desoxyartemisinin had no effect on extension/neurite formation. We propose a potential mechanism for neurotoxicity of artemisinin and its derivatives that involves the endoperoxide bridge which is also known to be necessary for their antimalarial action.

Ileocystoplasty in children: assessing safety and success.

From 1987 to 1992, bladder augmentation using clam ileocystoplasty was performed in 39 children 1.5-17.5 years old (mean age 9.7 years). Indications for augmentation included neuropathic bladder, epispadias-exstrophy complex and posterior urethral valves. A satisfactory bladder capacity at safe storage pressures of < 20 cm saline was achieved in all patients. Hydroureteronephrosis resolved or improved in 33 of the 36 moieties (91.7%). No patient showed biochemical or radiological deterioration of the upper tracts. The incidence of symptomatic urinary tract infection fell significantly postoperatively. Seven patients (17.9%) developed a total of 10 complications, with rupture of the augmented bladder occurring in 4 patients (10.3%).