Preliminary characterisation of an in vitro paradigm for the study of the delayed effects of organophosphorus compounds: hen embryo brain spheroids

Organophosphate induced delayed neuropathy (OPIDN) has been studied extensively but the mechanisms of toxicity remain unclear. It is generally accepted that the inhibition and ageing (dealkylation) of the B-esterase neuropathy target esterase (NTE) is integral to axonal loss. At present, the only way of detecting compounds that induce OPIDN is the hen test, an animal model. In this study, we preliminary validated hen embryo brain spheroids (HEBS) for the study of organophosphate (OP) toxicity. Hen brain spheroids have been characterised previously, although they have never been fully optimised for OP testing. We optimised the levels of acetylcholine esterase (AChE) and neuropathy target esterase by adapting the culture technique and using chemically defined media. Spheroid cultures were maintained for 35 days and viability and enzyme levels were monitored over this time. Levels of AChE and NTE in this system remained stable over the 35 day period. Using transmission electron microscopy, we have shown synaptogenesis within HEBS earlier than previously suggested in spheroid culture. These studies indicate that HEBS may be useful for the study of OP-induced toxicity and that the long-term stability of the cultures makes it an ideal candidate for studying OPIDN.     

Protocol for the administration of haemofiltration fluids and using patient group electrolytes direction

A patient group direction (PGD) is a specific written instruction for the supply or administration of named medicines in an identified clinical situation The introduction of a PGD must demonstrate a benefit for patients Haemofiltration is widely accepted as the treatment of choice when caring for critically ill patients in acute renal failure on an intensive care unit The haemofiltration PGD improves patient care by providing standardisation in administration of fluids and electrolytes and enabling nurses to respond rapidly to changes in biochemistry during haemofiltration This paper describes the development and implementation of a protocol to enable nurses to administer haemofiltration fluids and electrolytes under a patient group direction.     

Studies on di- and triterpenoids from Salvia staminea with cytotoxic activity

A new ursane-type triterpenoid, 3 beta,11 alpha,21 alpha-trihydroxyurs-12-ene, named salvistamineol (1), has been isolated from the methanol extract of Salvia staminea. In addition to 1, the methanol extract yielded four known compounds and the acetone extract yielded twelve known compounds consisting of two sesquiterpenes, six diterpenoids, a triterpenoid, two steroids and one flavone. DNA damaging properties of the extracts and some isolated diterpenes were investigated against three yeasts and only taxodione gave a positive response and also showed the highest cytotoxic activity against a panel of cell lines among the investigated compounds in this study.     

A novel cytotoxic guttiferone analogue from Garcinia macrophylla from the Suriname rainforest

Bioassay-guided fractionation of the EtOAc extract of the twigs of Garcinia macrophylla from Suriname produced the known benzophenone, guttiferone A (1), and a new guttiferone analogue, guttiferone G (2). Friedelin was also isolated. The structures of compounds 1 and 2 were elucidated using 1D and 2D NMR spectroscopy. Compounds 1 and 2 were weakly cytotoxic in the A2780 human ovarian cell line, with IC (50) values of 6.8 and 8.0 microg/mL, respectively.     

(S)-3,4-DCPG, a potent and selective mGlu8a receptor agonist, activates metabotropic glutamate receptors on primary afferent terminals in the neonatal rat spinal cord

(S)-3,4-Dicarboxyphenylglycine (DCPG) has been tested on cloned human mGlu1-8 receptors individually expressed in AV12-664 cells co-expressing a rat glutamate/aspartate transporter and shown to be a potent and selective mGlu8a receptor agonist (EC(50) value 31+/-2 nM, n=3) with weaker effects on the other cloned mGlu receptors (EC(50) or IC(50) values >3.5 microM on mGlu1-7).Electrophysiological characterisation on the neonatal rat spinal cord preparation revealed that (S)-3,4-DCPG depressed the fast component of the dorsal root-evoked ventral root potential (fDR-VRP) giving a biphasic concentration-response curve showing EC(50) values of 1.3+/-0.2 microM (n=17) and 391+/-81 microM (n=17) for the higher and lower affinity components, respectively. The receptor mediating the high-affinity component was antagonised by 200 microM (S)-alpha-methyl-2-amino-4-phosphonobutyrate (MAP4, K(D) value 5.4+/-1.5 microM (n=3)), a group III metabotropic glutamate (mGlu) receptor antagonist. The alpha-methyl substituted analogue of (S)-3,4-DCPG, (RS)-3,4-MDCPG (100 microM), antagonised the effects of (S)-3,4-DCPG (K(D) value 5.0+/-0.4 microM, n=3) in a similar manner to MAP4. (S)-3,4-DCPG-induced depressions of the fDR-VRP in the low-affinity range of the concentration-response curve were potentiated by 200 microM (S)-alpha-ethylglutamate (EGLU), a group II mGlu receptor antagonist, and were relatively unaffected by MAP4 (200 microM). However, depressions of the fDR-VRP mediated by the AMPA selective antagonist (R)-3,4-DCPG were not potentiated by EGLU, suggesting that the low-affinity component of the concentration-response curve for (S)-3,4-DCPG is not due to antagonism of postsynaptic AMPA receptors. It is suggested that the receptor responsible for mediating the high-affinity component is mGlu8. The receptor responsible for mediating the low-affinity effect of (S)-3,4-DCPG has yet to be identified but it is unlikely to be one of the known mGlu receptors present on primary afferent terminals or an ionotropic glutamate receptor of the AMPA or NMDA subtype.     

Pediatric sedation: contributing to evidence-based practice

Sedation of pediatric patients is a current practice issue; however, little has been published on performance measurement or evidence-based practice. The development of educational initiatives, the design of performance-improvement activities, and the validation of practice standards are described. Performance measures specific to the process of sedating pediatric patients are examined to show how to turn data into useful information to guide decision-making and nursing-practice changes.     

Eczema and atopy in early childhood: low IgA plasma cell counts in the jejunal mucosa.

Twenty-one children aged between 2 and 54 months, 14 with eczema and 7 with allergies in first-degree relatives, were referred for diagnostic jejunal mucosal biopsy for a variety of symptoms. A partial villous atrophy was found in 19 of the 21 biopsies obtained; the other 2 were normal. We report a highly significant (P less than 0.0001) lower IgA cell count in biopsies with partial villous atrophy compared with the results of our previous study of IgA and IgM plasma cells in the mucosal biopsies in children without eczema or a history of atopy matched for age and histological appearances. The IgM cell count was also lower.     

CAMPATH-1H IN RHEUMATOID ARTHRITIS--AN INTRAVENOUS DOSE-RANGING STUDY

Forty-one patients with active and refractory rheumatoid arthritis(RA) received a total of 100, 250 or 400 mg of CAMPATH-1H (CAMPATHis a trademark of Glaxo-Wellcome group companies, registeredin the US Patent and Trademark Office) over 5 or 10 days inan open, uncontrolled study. Following therapy, patients weremonitored for adverse effects and disease activity for 6 months.Therapy was associated with prolonged peripheral blood lymphopeniain all dosing cohorts. During the month immediately followingtherapy, lymphopenia was most profound in the 400 mg cohorts.The first dose of monoclonal antibody (Mab) was associated witha ‘flu’-like syndrome, more pronounced at higherinitial doses. One patient developed haemolytic-uraemic syndrome.There were a number of dose-related infections during the earlypost-treatment period and one fatal opportunistic infectionwhich followed additional immunosuppressive therapy. Antiglobulinresponses developed in 9 of 31 patients tested. The majorityof patients showed symptomatic improvement following therapyand 20% of patients maintained a 50% Paulus response at 6 months,all of whom were in the 250 or 400 mg cohorts. CAMPATH- 1H appearsto be an effective treatment for RA. Allowing for the smallnumber of patients treated, infections were more common withhigher doses, although this was not true for adverse eventsoverall, and therapeutic responses were more sustained at higherdosing levels. The broad specificity of CAMPATH- 1H may be appropriatefor the immunotherapy of RA and future studies should aim todefine a dose with an optimal therapeutic ratio. KEY WORDS: CAMPATH-1H, Rheumatoid arthritis, Immunotherapy, Monoclonal antibody, Antiglobulin response