Protection against nerve agent poisoning by a noncompetitive nicotinic antagonist

The acute toxicity of organophosphorus (OP) nerve agents arises from accumulation of acetylcholine (ACh) and overstimulation of ACh receptors. The mainstay of current pharmacotherapy is the competitive muscarinic antagonist, atropine. Nicotinic antagonists have not been used due to the difficulties of administering a dose of a competitive neuromuscular blocker sufficient to antagonise the effects of excessive ACh, but not so much that it paralyses the muscles. An alternative approach would be to use a noncompetitive antagonist whose effects would not be overcome by increasing ACh concentrations. This study demonstrates that the compound 1,1'-(propane-1,3-diyl)bis(4-tert-butylpyridinium), which blocks open nicotinic ion channels noncompetitively, is able to reverse the neuromuscular paralysis after nerve agent poisoning in vitro and to protect guinea pigs against poisoning by nerve agents when used as part of a therapeutic drug combination including a muscarinic antagonist. In contrast to the oxime HI-6, this compound was equally effective in protecting against poisoning by sarin or tabun. Further studies should identify more effective compounds with this action and optimise doses for protection against nerve agent poisoning in vivo.

Postprandial metabolism of Pacific bluefin tuna (Thunnus orientalis)

Specific dynamic action (SDA) is defined as the energy expended during ingestion, digestion, absorption and assimilation of a meal. This study presents the first data on the SDA response of individual tunas of any species. Juvenile Pacific bluefin tunas (Thunnus orientalis; body mass 9.7–11.0 kg; N=7) were individually fed known quantities of food consisting primarily of squid and sardine (meal energy range 1680–8749 kJ, ~4–13% of tuna body mass). Oxygen consumption rates () were measured in a swim tunnel respirometer during the postprandial period at a swimming speed of 1 body length (BL) s−1 and a water temperature of 20°C. was markedly elevated above routine levels in all fish following meal consumption [routine metabolic rate (RMR)=174±9 mg kg−1 h−1]. The peak during the SDA process ranged from 250 to 440 mg kg−1 h−1 (1.5–2.3 times RMR) and was linearly related to meal energy content. The duration of the postprandial increment in ranged from 21 h to 33 h depending upon meal energy content. Consequently, the total energy used in SDA increased linearly with meal energy and ranged from 170 kJ to 688 kJ, such that the SDA process accounted for 9.2±0.7% of ingested energy across all experiments. These values suggest rapid and efficient food conversion in T. orientalis in comparison with most other fishes. Implanted archival temperature tags recorded the increment in visceral temperature (TV) in association with SDA. returned to routine levels at the end of the digestive period 2–3 h earlier than TV. The qualitative patterns in and TV during digestion were similar, strengthening the possibility that archival measurements of TV can provide new insight into the energetics and habitat utilization of free-swimming bluefin in the natural environment. Despite efficient food conversion, SDA is likely to represent a significant component of the daily energy budget of wild bluefin tunas due to a regular and high ingestion of forage.

Selection of peptide ligands for the antimucin core antibody C595 using phage display technology: definition of candidate epitopes for a cancer vaccine

Aims-To further define the specificity of the antimucin core antibody C595 by fitting it with a family of hexapeptide ligands by immunoselection of filamentous bacteriophage from a gene III display library of approximately 6.4 x 10(7) random hexapeptides.Methods-Three rounds of immuno-selection were used to enrich for C595 binding phage. DNA sequencing revealed the hexapeptides expressed. Bacteriophage and corresponding synthetic hexapeptides were used in ELISA assay to determine binding affinities.Results-Twenty nine clones from this selected population were analysed. Seven contained the natural epitope RPAP, encoded by two different DNA sequences; 17/29 contained the motif RLPP. In all, 28/29 clones contained the motif RXXP and one clone (RVRPAP) contained the motif RXXP in two peptidic registers; 24/28 clones (6/8 DNA sequences) contained a hydrophobic residue (V or I) at position 1 relative to the RXXP motif. In addition the proximity of RXXP to glycine (position 5) suggests that this contributes in the natural epitope to antibody/antigen binding, which was not detected by chemical synthetic methods. One clone, KSKAGV, bears no obvious relationship to the natural epitope and therefore qualifies as a weakly binding mimotope.Conclusions-This approach has rapidly defined the specificity of this antibody in unprecedented detail, and provides a more comprehensive molecular basis for exploring the immune recognition of the MUC1 mucin by the C595 antibody. Importantly, the novel but related epitopes seen provide peptide specificities and a strategy which may prove useful in generating cancer vaccine candidates.

The fate of elderly patients discharged from the accident and emergency department of a general teaching hospital

This paper describes the experience of a cohort of elderly patients who were discharged after attending the accident and emergency department of a large Australian teaching hospital. Before-and-after comparisons of aspects of physical functioning revealed a considerable loss of independence in the period immediately after the visit to the hospital. Subsequent hospital admission or death was observed in 30 of the 90 patients studied. It is suggested that elderly patients discharged from the accident and emergency department are at risk and require special consideration and a high index of suspicion in terms of evaluation at the time of presentation. Before discharge, account should be taken of aspects of physical and mental function, social networks, and community supports available to each patient. A lowered threshold for admission is recommended on the basis of the high rate of return found in this study.

Sensitivity and specificity of HIV rapid tests used for research and voluntary counselling and testing

BACKGROUND

HIV rapid tests (RT) are a quick and non-technically demanding means to perform HIV voluntary counselling and testing (VCT) but understanding their limitations is vital to delivering quality VCT.

OBJECTIVE

To determine the sensitivity and specificity of HIV rapid tests used for research and voluntary counselling and testing at four sites in East Africa.

DESIGN

Cross-sectional study.

SETTING

Masaka District, Uganda; a sugar plantation in Kakira, Uganda; Coastal Villages in the Kilifi District of Kenya; and the Urban slum of Kangemi located West of Nairobi, Kenya.

SUBJECTS

Six thousands two hundred and fifty five consenting volunteers were enrolled into the study, and 675 prevalent HIV infections were identified.

RESULTS

The RT sensitivity tended to be high for all assays at all sites (97.63-100%) with the exception of the Uni-Gold assay (90.24% in Kangemi, 96.58% in Kilifi). Twenty four RT results were recorded as 'weak positives', 22 (92%) of which were negative by ELISA. There was a high rate of RT false positives in Uganda (positive predictive values ranging from 45.70% to 86.62%).

CONCLUSIONS

The sensitivity and specificity of the RT varied significantly across sites. The rate of RT misclassification in Uganda suggests that a multiple test algorithm may be preferable to a single test as screener for HIV VCT.

Bispectral Index asymmetry and COMFORT score in paediatric intensive care patients

BACKGROUND

The Bispectral Index (BIS) monitor has been suggested as a potential tool to measure depth of sedation in paediatric intensive care unit (PICU) patients. The primary aim of our observational study was to assess the difference in BIS values between the left and right sides of the brain. Secondary aims were to compare BIS and COMFORT score and to assess change in BIS with tracheal suctioning.

METHODS

Nineteen ventilated and sedated PICU patients had paediatric BIS sensors applied to either side of their forehead. Each patient underwent physiotherapy involving tracheal suctioning. Their BIS data and corresponding COMFORT score, assessment as by their respective nurses, were recorded before, during, and after physiotherapy.

RESULTS

Seven patients underwent more than one physiotherapy session; therefore, 28 sets of data were collected. The mean BIS difference values (and 95% CI) between left BIS and right BIS for pre-, during, and post-physiotherapy periods were 9.2 (5.9-12.5), 15.8 (11.9-19.7), and 7.5 (5.2-9.7), respectively. Correlation between mean BIS, left brain BIS, and right brain BIS to COMFORT score was highly significant (P<0.001 for all three) during the pre- and post-physiotherapy period, but less so during the stimulated physiotherapy period (P=0.044, P=0.014, and P=0.253, respectively).

CONCLUSIONS

A discrepancy between left and right brain BIS exists, especially when the patient is stimulated. COMFORT score and BIS correlate well between light and moderate sedation.

Impact of risperidone long acting injection on resource utilization in psychiatric secondary care

Risperidone long acting injection (RLAI) is the only long acting atypical antipsychotic available in the UK. Its impact on NHS resource use has not been widely studied. This review of medical records was conducted to quantify the impact of RLAI on NHS psychiatric secondary care resource use, primarily in terms of episodes of inpatient hospital care 12 months before and 12 months after RLAI initiation. Data on number of hospitalizations and hospital bed days were collected retrospectively, from patient notes and hospital databases in four acute psychiatric units in the UK for all individuals with a diagnosis of schizophrenia or schizoaffective disorder who were prescribed RLAI more than 12 months previously. Data were collected on 100 individuals (58 male) with a mean age 40.8 years (range 19-70). The median duration of illness before RLAI initiation was 12 years (range six months to 43 years). There were 62 admissions in the 12 months pre-RLAI, falling to 22 admissions in the 12 months post-RLAI. Number of admissions, we argue, offer a more reliable indicator of the impact of treatment than total hospital bed days in this type of study. In this study there were 40 fewer admissions in the 12 months after RLAI was initiated compared with the previous 12 months. This is important as readmission is a good proxy measure of relapse, and adherence to medication is known to be a key factor in relapse prevention.

An analysis quantifies prostate brachytherapy swelling using peripheral seeds as fiducial reference points

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Background: Permanent prostate brachytherapy (PPB) assesses implant quality but may suffer significant variability due to: 1) Prostate edema may occur during the procedure which usually subsides within several months, and 2) interobserver variability of CT- derived prostate volumes. An analysis is described, which uses the seeds as prostate fiducials to produce an implant reference volume (IRV). The ratio of the IRV volumes at day 0 and day 33 provides a unique way to quantify prostate edema; thus reducing this factor as a source of variability. Methods: Thirteen low risk prostate cancer patients, (Stage ≤ T2, PSA<13.9, Gleason Score ≤7) were implanted with 125Iodine seeds (77% stranded; prescription dose of 145 Gy). PPB was completed for each patient on day 0 and 33 ±3 days following the implant. The IRV was defined as the volume obtained by contouring the outer most peripheral seeds, circumferentially, on each axial image, resulting in a 3D volume. Contouring was performed by three separate investigators (KJM, DCG, EKM), who were blinded with respect to patient identification. The IRV's were compared both by investigator and by time of PPB (day 0 vs. day 33). The radiation dose encompassing 90% (D90) of the IRV and Prostate (PST) was calculated and compared . Results: The IRVs contoured were reproducible between the investigators with a maximum mean difference of .56 (SD .33) cc. There was no statistical difference between any of the investigators contoured volume (minimum Spearman correlation was 0.978). The average IRV was significantly larger on day 0 (Avg. 52.7;SD 19.7 cc) compared to day 33 (Avg. 44.6; SD 19.1 cc) (p<0.001). The day 0 IRV was an average of 1.18 times larger than the Day 33 PRV. There was no difference between either the day 0 D90PST (Avg.149.1; SD18.7 cGy) vs the day 0 D90IRV (Avg.149.8, SD 27.5 cGy) (p=.442) nor between the day 33 D90PST (Avg.163.7; SD22.7 cGy) vs the day 33 D90IRV (Avg.166.6, SD 30.3 cGy) (p=.257). Both the D90IRV and D90PST were significantly different at day 0 vs 33 (p=.0003, p=<.0001 respectively). Conclusions: The IRV analysis demonstrates no significant interobserver variability, provides accurate quantification of prostate swelling after PPB, and is an accurate objective surrogate analysis for PSI quality.

No significant financial relationships to disclose.

Multi-clinical laboratory validation of a gene expression-based tissue of origin test applied to poorly differentiated and undifferentiated cancers

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Background: This multi-clinical laboratory validation assessed the accuracy, reproducibility and robustness of the Pathwork™ Tissue of Origin Test. We focused on tumor specimens that are poorly differentiated to undifferentiated (G3-G4; high grade) because this type of specimen can consume a disproportionate amount of physician time and diagnostic resources. A subset of this type of specimen ultimately will be categorized as cancer of unknown primary (CUP), which comprises 4–5% of all malignancies. The Test uses proprietary analytics and a companion genomic microarray (Pathchip™) to compare expression levels of poorly differentiated to undifferentiated specimens with 15 types of cancer. Test development involved over 2000 specimens from 14 labs, representing 15 cancers and sixty morphologies. Methods: The studies addressed operability limits, specimen stability, potential interferences and reproducibility, as well as validation in molecular diagnostics and commercial laboratories. In all, over 700 frozen tumor specimens and microarrays were analyzed. Results: Clinical validation data demonstrated that the percent agreement of the Tissue of Origin Test was 88% across all tissue types. Between-lab concordance was 95%. If the quantitative result (Similarity Score) exceeded the recommended threshold, the probability that the indicated tissue is present was 95% across all tissue types. If the Similarity Score was less than 5, the probability that the indicated tissue is absent was 98% across all tissues types. Conclusions: The Pathwork™ Tissue of Origin Test, which is under development, is accurate and highly reproducible across laboratories in this study. The test gave consistent results for different tissue handling and extraction methods and has the potential to be an effective aid in the diagnosis of cancer patients presenting with poorly differentiated and undifferentiated tumors.

No significant financial relationships to disclose.

Warfarin response and vitamin K epoxide reductase complex 1 in African Americans and Caucasians

The objective of this study was to determine whether two vitamin K epoxide reductase complex 1 (VKORC1) polymorphisms contribute to the variability in warfarin response, particularly in African Americans. The effect of the VKORC1 1173C/T and -1639G/A polymorphisms was examined in a prospective cohort study of 338 warfarin users. Subjects carrying an 1173T allele had a lower warfarin maintenance dose compared with subjects with the CC genotype in African Americans (-12.10 mg/week+/-4.93; P=0.02) and Caucasians (-14.41 mg/week+/-3.28; P<0.001). Before reaching maintenance dose, only Caucasians with the T allele had significantly increased risk of international normalized ratio >3 (odds ratio=3.10; 95% confidence interval: 1.73-5.55) compared with Caucasians with the CC genotype. Polymorphisms in the VKORC1 gene are associated with warfarin maintenance dose requirements among both African Americans and Caucasians. However, these polymorphisms may not be as useful in predicting over-anticoagulation among African Americans.

Apolipoprotein E genotype and warfarin dosing among Caucasians and African Americans

Warfarin sodium is a vitamin K antagonist that is plagued by large variability in patient response, including higher dose requirements among African Americans. Polymorphisms in the gene encoding apolipoprotein E (APOE) may partly explain this variability by altering transport of vitamin K to the liver. In a prospective cohort study of 232 individuals (52.2% Caucasian and 47.8% African American) initiating warfarin therapy, the weekly maintenance dose was significantly higher for African Americans than for Caucasians (mean 42.9 versus mean 36.9 mg, P=0.018), and the epsilon4 allele was more common among African Americans (37.8 versus 26.4% for Caucasians). In multivariable analyses, the presence of the epsilon4 allele was associated with a statistically significantly higher warfarin dose among African Americans (median 45.0 mg in epsilon4 carriers versus 35.0 mg in non-epsilon4 carriers, P=0.014) but not Caucasians (38.1 versus 35.0 mg, P=0.60). In addition, warfarin maintenance dose increased among African Americans according to genotype previously associated with differential hepatic chylomicron clearance (epsilon2/epsilon2 or epsilon2/epsilon3: 30.0 mg; epsilon3/epsilon3: 35.0 mg; epsilon3/epsilon4 or epsilon4/epsilon4: 45.0 mg; P=0.012), although the epsilon4/epsilon4 genotype was rare and not clearly associated with higher doses. The association of APOE with warfarin dosing was independent of CYP2C9 and VKORC1 polymorphisms. APOE polymorphisms thus may be important determinants of warfarin maintenance dose and could explain at least some of the observed racial differences in dose requirements.

Improving the fundamental aspects of patient care

The Welsh Assembly Government published the document Fundamentals of Care (2003) to support measures for quality improvement of care in Wales. This article reports on the progress being made in raising awareness of this framework and improving the quality of patient care in one large integrated NHS trust. The trust's steering group was instrumental in putting the guidance into action, which resulted in project development and improved practice.

Role of the JNK pathway in NMDA-mediated excitotoxicity of cortical neurons

Excitotoxic insults induce c-Jun N-terminal kinase (JNK) activation, which leads to neuronal death and contributes to many neurological conditions such as cerebral ischemia and neurodegenerative disorders. The action of JNK can be inhibited by the D-retro-inverso form of JNK inhibitor peptide (D-JNKI1), which totally prevents death induced by N-methyl-D-aspartate (NMDA) in vitro and strongly protects against different in vivo paradigms of excitotoxicity. To obtain optimal neuroprotection, it is imperative to elucidate the prosurvival action of D-JNKI1 and the death pathways that it inhibits. In cortical neuronal cultures, we first investigate the pathways by which NMDA induces JNK activation and show a rapid and selective phosphorylation of mitogen-activated protein kinase kinase 7 (MKK7), whereas the only other known JNK activator, mitogen-activated protein kinase kinase 4 (MKK4), was unaffected. We then analyze the action of D-JNKI1 on four JNK targets containing a JNK-binding domain: MAPK-activating death domain-containing protein/differentially expressed in normal and neoplastic cells (MADD/DENN), MKK7, MKK4 and JNK-interacting protein-1 (IB1/JIP-1).