B-36 Effects of Electroconvulsive Therapy on Cognitive Performance and Depressive Symptoms: A Naturalistic Study

Objective

1) Examine the short- and long-term effects of electroconvulsive therapy (ECT)—conducted in a naturalistic treatment setting—on objective and subjective cognitive functioning. 2) Examine the long-term effects of naturalistic ECT on depressive symptoms.

Method

Participants (N = 108) were outpatients (aged 18-65) diagnosed with a Major Depressive Episode who received ECT at St. Joseph’s Healthcare Hamilton, Ontario. Parameters of ECT varied clinically. Participants completed a cognitive and psychological test battery at baseline (n = 108), mid-treatment (n = 82), 2–6-weeks post-ECT (n = 52), 6-months post-ECT (n = 24), and 12-months post-ECT (n = 14) that included Repeatable Battery for Assessment of Neuropsychological Status (RBANS), Squire Subjective Memory Questionnaire (SSMQ), Beck Depression Inventory-II (BDI-II), and WHO Disability Assessment Schedule (WHODAS-2).

Results

Overall cognitive performance (total RBANS scaled scores) did not improve from baseline to 2-6 weeks post-ECT (p = 0.156), significantly improved from baseline to 6-months post-ECT (t(22) = -2.34, p = .026, CI: = -8.93– -0.63), but were not maintained at 12-months post-ECT (p = 0.20). SSMQ scores significantly worsened from baseline to mid-ECT (t(75) = -5.04, p < .001, CI: -17.53– -7.60), but returned to baseline levels by 2–6-weeks post-ECT. Depressive symptoms (BDI-II) significantly improved by the 4th ECT session and gains were maintained across all timepoints (p < 0.004). WHODAS-2 scores significantly improved from baseline and were maintained across follow-up (t < 0.05).

Conclusion

ECT was effective at improving depressive symptoms in a naturalistic setting with diverse patient presentations. Preliminary findings show minimal, if any, gains in cognitive performance–although, functioning did not appear to worsen following ECT. RBANS may not be sufficiently sensitive. Developing recommendations for conducting and evaluating ECT in naturalistic settings marks an essential next step.

Communicating biosecurity information to Australian-registered veterinarians

OBJECTIVE

Updating veterinarians (vets) on the latest biosecurity resources, information and alerts is important to ensure protection of domesticated and native animals. This preliminary questionnaire aimed to better understand the communication preferences of Australian-registered vets for biosecurity information, and their trust of these sources.

METHODS

An online questionnaire asking vets about their current communication preferences for biosecurity information, and their level of trust of these was created and distributed to Australian-registered vets.

RESULTS

Survey respondents (158) use and highly trust communication from (in order) vet and animal health organisations, vet surgeons' boards, the scientific literature, and government agencies.

CONCLUSIONS

This preliminary study identifies that using vet surgeon's boards, government agencies and vet and animal health organisations may be an effective means for communicating biosecurity information to vets. Future research should consider which sources vets trust and why, to facilitate effective communication to them and the clients they serve.

Congenital Hypothalamic "Hamartoblastoma" Versus "Hamartoma": Suggestions for Neuropathologic Terminology Emanating From a Mid-gestational Autopsy Case of Pallister-Hall Syndrome

Pallister-Hall syndrome (PHS) is a rare malformative disorder that is due to truncating functional repressor mutations in GLI3. Since the seminal publication in 1980, hypothalamic tumors have been recognized to be a cardinal feature of PHS. In their original description of the neuropathologic features of PHS, Clarren et al. coined the term "hamartoblastoma" to characterize what they deemed to be a dual malformative and neoplastic mass of the hypothalamus. In subsequent published cases/series of PHS, the term "hamartoma" was often substituted for hamartoblastoma given what appeared to be a benign natural history of this lesion. Additional confusion in the literature has ensued since most hypothalamic hamartomas (HH) encountered on the clinical neuropathology service are "isolated" in nature (ie, no other congenital malformations) and present in a very different and stereotypical fashion with gelastic seizures and/or precocious puberty. While genomic investigations of isolated HH have begun to uncover a mutational profile of these cases, GLI3 mutations have only been recognized in a small subset of isolated HH. Herein, we describe the autopsy findings from a 21-week gestational age fetus with features of PHS. Moreover, we provide a detailed description of the hypothalamic tumor affecting this fetus and propose a novel subclassification of HH, distinguishing syndromic from isolated forms based upon the presence or absence of neocortical-like areas.

Practice and documentation of palliative sedation: a quality improvement initiative

BACKGROUND

Palliative sedation (ps), the continuous use of sedating doses of medication to intentionally reduce consciousness and relieve refractory symptoms at end of life, is ethically acceptable if administered according to standards of best practice. Procedural guidelines outlining the appropriate use of ps and the need for rigorous documentation have been developed. As a quality improvement strategy, we audited the practice and documentation of ps on our palliative care unit (pcu).

METHODS

A pharmacy database search of admissions in 2008 identified, for a subsequent chart review, patients who had received either a continuous infusion of midazolam (≥10 mg/24 h), regular parenteral dosing of methotrimeprazine (≥75 mg daily), or regular phenobarbital. Documentation of the decision-making process, consent, and medication use was collected using a data extraction form based on current international ps standards.

RESULTS

Interpretation and comparison of data were difficult because of an apparent lack of a consistent operational definition of ps. Patient records had no specific documentation in relation to ps initiation, to clearly identified refractory symptoms, and to informed consent in 60 (64.5%), 43 (46.2%), and 38 (40.9%) charts respectively. Variation in the medications used was marked: 54 patients (58%) were started on a single agent and 39 (42%), on multiple agents. The 40 patients (43%) started on midazolam alone received a mean daily dose of 21.4 mg (standard deviation: 24.6 mg).

CONCLUSIONS

The lack of documentation and standardized practice of ps on our pcu has resulted in a quality improvement program to address those gaps. They also highlight the importance of conducting research and developing clinical guidelines in this area.

Theory of mind performance in women with posttraumatic stress disorder related to childhood abuse

OBJECTIVE

Key questions remain unaddressed concerning the nature of interpersonal functioning in trauma survivors, including the ability to understand and interpret other people's thoughts and feelings. Here, we investigate theory of mind (ToM) performance of women with PTSD related to childhood abuse in comparison to healthy controls.

METHOD

Participants completed two ToM tasks, the Interpersonal Perception Task-15 (IPT-15) and the Reading the Mind in the Eyes Task - Revised (RMET).

RESULTS

Relative to controls, women with a history of childhood trauma had difficulty recognizing familial relationships depicted in the IPT-15 (P = 0.005). No other category of the IPT-15 showed significant group differences. In addition, while healthy women displayed faster RMET reaction times to emotionally valenced mental states (positive: P = 0.003; negative: P = 0.016) compared with neutral mental states, the PTSD group showed similar reaction times across all valences. The presence of dissociative symptoms (e.g., disengagement, amnesia, identity dissociation) was strongly associated with hindered accuracy of complex mental state identification and altered perception of kinship interactions.

CONCLUSION

Women with PTSD stemming from childhood trauma show changes in ToM abilities particularly those often involved in the interpretation of family interactions. In addition, individuals with PTSD showed slower reaction times during the recognition of complex mental states from emotionally salient facial/eye expressions in comparison with healthy subjects.

University students' notebook computer use: lessons learned using e-diaries to report musculoskeletal discomfort

The objective of this pilot study was to identify if notebook accessories (ergonomic chair, desktop monitor and notebook riser) combined with a wireless keyboard, mouse and participatory ergonomics training would have the greatest impact on reducing self-reported upper extremity musculoskeletal discomfort in university students. In addition to pre-post computing and health surveys, the Ecological Momentary Assessment was used to capture change in discomfort over time using a personal digital assistant (PDA) as the e-diary. The PDA was programmed with a survey containing 45 questions. Four groups of university students were randomised to either intervention (three external computer accessories) or to control. Participants reported less discomfort with the ergonomic chair and notebook riser based on the pre-post survey data and the e-diary/PDA ANOVA analysis. However, the PDA data, adjusted for the effect of hours per day of computer use, showed no benefit of the chair and limited benefit from the riser. Statement of Relevance:University students' use of notebook computers has increased. This study found evidence of a positive effect of an adjustable chair or notebook riser when combined with ergonomic training on reducing discomfort. Daily notebook computer use of 4 h was confirmed as a risk factor. Without some form of ergonomic intervention, these students are likely to enter the workforce with poor computing habits, which places them on the road to future injuries as technology continues to play a dominant role in their lives.

A collaborative hit-to-lead investigation leveraging medicinal chemistry expertise with high throughput library design, synthesis and purification capabilities

High throughput screening (HTS) campaigns, where laboratory automation is used to expose biological targets to large numbers of materials from corporate compound collections, have become commonplace within the lead generation phase of pharmaceutical discovery. Advances in genomics and related fields have afforded a wealth of targets such that screening facilities at larger organizations routinely execute over 100 hit-finding campaigns per year. Often, 10(5) or 10(6) molecules will be tested within a campaign/cycle to locate a large number of actives requiring follow-up investigation. Due to resource constraints at every organization, traditional chemistry methods for validating hits and developing structure activity relationships (SAR) become untenable when challenged with hundreds of hits in multiple chemical families per target. To compound the issue, comparison and prioritization of hits versus multiple screens, or physical chemical property criteria, is made more complex by the informatics issues associated with handling large data sets. This article describes a collaborative research project designed to simultaneously leverage the medicinal chemistry and drug development expertise of the Novartis Institutes for Biomedical Research Inc. (NIBRI) and ArQule Inc.'s high throughput library design, synthesis and purification capabilities. The work processes developed by the team to efficiently design, prepare, purify, assess and prioritize multiple chemical classes that were identified during high throughput screening, cheminformatics and molecular modeling activities will be detailed.

A new siglec family member, siglec-10, is expressed in cells of the immune system and has signaling properties similar to CD33

The siglecs (sialic acid-binding Ig-like lectins) are a distinct subset of the Ig superfamily with adhesion-molecule-like structure. We describe here a novel member of the siglec protein family that shares a similar structure including five Ig-like domains, a transmembrane domain, and a cytoplasmic tail containing two ITIM-signaling motifs. Siglec-10 was identified through database mining of an asthmatic eosinophil EST library. Using the Stanford G3 radiation hybrid panel we were able to localize the genomic sequence of siglec-10 within the cluster of genes on chromosome 19q13.3-4 that encode other siglec family members. We have demonstrated that siglec-10 is an immune system-restricted membrane-bound protein that is highly expressed in peripheral blood leukocytes as demonstrated by Northern, RT-PCR and flow cytometry. Binding assays determined that the extracellular domain of siglec-10 was capable of binding to peripheral blood leukocytes. The cytoplasmic tail of siglec-10 contains four tyrosines, two of which are embedded in ITIM-signaling motifs (Y597 and Y667) and are likely involved in intracellular signaling. The ability of tyrosine kinases to phosphorylate the cytoplasmic tyrosines was evaluated by kinase assay using wild-type siglec-10 cytoplasmic domain and Y-->F mutants. The majority of the phosphorylation could be attributed to Y597 andY667. Further experiments with cell extracts suggest that SHP-1 interacts with Y667 and SHP-2 interacts with Y667 in addition to another tyrosine. This is very similar to CD33, which also binds the phosphatases SHP-1 and SHP-2, therefore siglec-10, as CD33, may be characterized as an inhibitory receptor.

Cytokine-specific transcriptional regulation through an IL-5Ralpha interacting protein

Cytokine receptors consist of multiple subunits, which are often shared between different receptors, resulting in the functional redundancy sometimes observed between cytokines. The interleukin 5 (IL-5) receptor consists of an IL-5-specific alpha-subunit (IL-5Ralpha) and a signal-transducing beta-subunit (betac) shared with the IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors. In this study, we sought to find a role for the cytoplasmic domain of IL-5Ralpha. We show that syntenin, a protein containing PSD-95/Discs large/zO-1 (PDZ) domains, associates with the cytoplasmic tail of the IL-5Ralpha. Syntenin was found to directly associate with the transcription factor Sox4. Association of syntenin with IL-5Ralpha was required for IL-5-mediated activation of Sox4. These studies identify a mechanism of transcriptional activation by cytokine-specific receptor subunits.

Modified peptide antagonists of interleukin 5 exhibit extended in vivo persistence but restricted species specificity

AF18748 is disulphide-linked homodimeric peptide with 19 amino acids in each chain that antagonises the action of the eosinophil-specific cytokine, interleukin 5 (IL-5). We have generated a set of N-terminally truncated peptides derived from AF18748 and demonstrated that the first five amino acids of the peptide do not contribute to receptor binding activity. The shortened peptide blocked IL-5-dependent adhesion of eosinophils with an IC(50)of 350 pM, and had no effect on stimulation by IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor (TNF)-alpha or fMet-Leu-Phe. The peptides were rapidly broken down in mouse plasma through cleavage of a single chain of the dimer. However, this breakdown did not correlate with loss of biological activity, indicating that the asymmetric peptide fragment retains full receptor binding capacity. The activity of AF18748 disappeared rapidly from the blood following intravenous injection into mice. Coupling of polyethylene glycol to the N-terminus of AF18748 resulted in a moderate loss in biological potency (IC(50)30 nM), but the resulting conjugate persisted in the circulation for more than 8 h after injection. Despite its high potency at the human IL-5 receptor, AF18748 was unable to antagonise the activity of IL-5 on murine B13 cells, or on canine eosinophils, indicating that the peptide is highly specific for the human IL-5 receptor.

A potent dimeric peptide antagonist of interleukin-5 that binds two interleukin-5 receptor alpha chains

Two series of peptides that specifically bind to the extracellular domain of the alpha chain of the human interleukin-5 receptor (IL-5Ralpha), but share no primary sequence homology to IL-5, were identified from libraries of random recombinant peptides. Affinity maturation procedures generated a 19-aa peptide that binds to the IL-5 receptor alpha/beta heterodimer complex with an affinity equal to that of IL-5 and is a potent and specific antagonist of IL-5 activity in a human eosinophil adhesion assay. The active form of the peptide is a disulfide-crosslinked dimer that forms spontaneously in solution. Gel filtration analysis, receptor-binding studies, and analytical ultracentrifugation reveal that the dimeric peptide binds simultaneously to two receptor alpha chains in solution. Furthermore, the dimer peptide, but not IL-5, can activate a chimeric receptor consisting of the IL-5Ralpha extracellular domain fused to the intracellular domain of the epidermal growth factor receptor, thus demonstrating that the peptide also promotes receptor dimerization in a cellular context. The functional antagonism produced by the bivalent interaction of the dimeric peptide with two IL-5R alpha chains represents a distinctive mechanism for the antagonism of cytokines that use heteromeric receptors.

Birthweights and growth of infants in five Aboriginal communities

OBJECTIVES

To improve, by culturally appropriate means, birthweights and growth of children up to three years of age over 14 months in five Aboriginal communities in north-western Australia.

METHODS

Frequent individual nutritional assessment of infants and children with counselling of mothers and carers and of pregnant women and the introduction of the Aboriginal-controlled Strong Women, Strong Babies, Strong Culture maternal support program. Outcomes compared with those in the same communities for the five years preceding intervention.

RESULTS

By international standards, pre-intervention birthweights of full-term infants (37-42 weeks) were only moderately depressed and recovered to exceed standard weight-for-age within two weeks of birth. Growth of full-term infants slowed abruptly after six months. Prevalence and duration of breastfeeding were very high. Prevailing low average birthweight was chiefly attributable to a prevalence of pre-term birth approaching 20%. Intervention was not accompanied by any change in full-term birth weight but was associated with increased weight gain after six months. From 12 to 36 months growth rose by 30 g per month (p = 0.001). Average birthweights of pre-term infants were < 2,500 g and average weight-for-age did not improve during intervention.

CONCLUSIONS

Both low birthweight and a disproportionate part of intransigent failure to grow by Aboriginal infants were associated with pre-term birth. Depressed average growth of full-term infants appeared to respond to nutritional counselling accompanied by a community support program.

IMPLICATIONS

Investigation of the causes of the exceptionally high rate of Aboriginal pre-term birth in the region is urgently required.

Shared care for high-dependency patients: mental illness, neurological disorders and terminal care--a review

Changes in the structure of health services in the UK have increased the need to identify and formalize shared responsibilities between primary and secondary care for patients with chronic conditions. There are well-established schemes for the management of patients with some chronic diseases but very little for other high-dependency groups. This review examines the extent of systematic and shared care for some of the less well served groups: these are mental illness, neurological disorders and terminal care. Examples of good practice are highlighted.

Primary care: past and future

There is anecdotal evidence of a crisis in the recruitment and retention of general practitioners nationwide and particularly in inner cities. The relationship between quality of service and single-handed or group practice is uncertain and confounded by other aspects of practice structure and populations. The review examines the factors that influence doctors to enter and remain in general practice. It explores whether initiatives designed to address problems of recruitment and retention have been evaluated in the past and suggests how could they inform current initiatives.

Clinical importance of identifying coagulase-negative staphylococci isolated from blood cultures: evaluation of MicroScan Rapid and Dried Overnight Gram-Positive panels versus a conventional reference method

We evaluated the clinical usefulness of species identification of blood isolates of coagulase-negative staphylococci as a predictor of the clinical significance of the isolates. In addition, we compared results of species identification obtained with MicroScan Rapid Gram-Positive Identification panels and Dried Overnight (Conventional) Gram-Positive Identification panels with those obtained by a tube reference method. Two hundred eighty-five blood isolates were tested, including 92 judged to represent true bacteremia and 193 judged to represent contamination. The most common species detected were Staphylococcus epidermidis, Staphylococcus hominis, and Staphylococcus haemolyticus. These three species accounted for nearly 98% of the clinically significant isolates and 89% of the contaminants. The isolation of other species almost always represented contamination. However, identification of the three most common species did not help distinguish pathogens from contaminants. Both the Rapid and the Dried Overnight Gram-Positive panels identified S. epidermidis strains accurately, but the panels performed less well for the other species. Analysis revealed that S. hominis was frequently misidentified due to the presence of a previously unknown subspecies. Based on the initial results, revised investigational Dried Overnight Gram-Positive Identification panels (CPID-2) were prepared and tested. The CPID-2 panels identified 85 to 95% of S. epidermidis strains, 76 to 86% of S. hominis strains, and 88 to 92% of S. haemolyticus strains with high probability (>85%) and, overall, represented a significant improvement over the other panels for identification of these staphylococcal species.

Non-mydriatic fundus photography: a viable alternative to fundoscopy for identification of diabetic retinopathy in an Aboriginal population in rural Western Australia?

PURPOSE

To evaluate the Canon CR5-45NM non-mydriatic fundus camera (Canon, Kanagawa, Japan) for identifying retinopathy and the need for laser treatment in a population of Aboriginal patients with diabetes mellitus in rural Western Australia.

METHODS

Diabetic Aboriginal patients were photographed through undilated pupils using a Canon CR5-45NM non-mydriatic fundus camera, after which ophthalmoscopy was performed using indirect ophthalmoscopy through dilated pupils. The examining ophthalmologist recorded the presence of retinopathy and the need for laser treatment. A proportion of patients were rephotographed through dilated pupils. Photographs were reviewed by a second ophthalmologist who evaluated the quality of the image, the presence of retinopathy and the need for laser treatment. Results of fundus photographs and ophthalmoscopy were compared.

RESULTS

Three hundred and twenty-eight eyes in 164 Aboriginal patients were examined. The mean patient age was 48.2 years (range 16-81 years) and the mean duration of diabetes was 7.5 years (range 1-35 years). Seventy-four eyes (22.6%) were diagnosed with retinopathy using combined examination techniques, 44 (59.5%) of which were identified by ophthalmoscopy and 55 (74.3%) by photography. Thirty-five eyes were deemed to need treatment, 18 (51.4%) of which were identified by ophthalmoscopy and 30 (85.7%) by photography. Kappa coefficient measurement for agreement for presence of retinopathy and need for referral was 0.41 and 0.53, respectively. Photograph quality was significantly improved following pupil dilation.

CONCLUSIONS

The Canon CR5-45NM non-mydriatic fundus camera was relatively good at identifying diabetic retinopathy and could usefully be applied within a screening programme for treatable disease within this population.

Tissues of MSH2-deficient mice demonstrate hypermutability on exposure to a DNA methylating agent

The mutational response of mismatch repair-deficient animals to the alkylating agent N-methyl-N-nitrosourea was evaluated by using a transgenic lacI reporter system. Although the mutations detected in MSH2 heterozygotes were similar to those of controls, MSH2-/- animals demonstrated striking increases in mutation frequency in response to this agent. G:C to A:T transitions at GpG sites, as opposed to CpG sites, dominated the mutational spectrum of both MSH2+/+ and MSH2-/- N-methyl-N-nitrosourea -treated animals. Extrapolating to humans with hereditary non-polyposis colorectal cancer, the results suggest that MSH2 heterozygotes are unlikely to be at increased risk of mutation, even when exposed to potent DNA methylating agents. In contrast, mismatch repair-deficient cells spontaneously arising within individuals with hereditary non-polyposis colorectal cancer would likely exhibit hypermutability in response to such mutagens, an outcome predicted to accelerate the pace of tumorigenesis.

Reliability of a comorbidity measure: the Index of Co-Existent Disease (ICED)

The reliability of an established comorbidity index (the Index of Co-Existent Disease) was tested using retrospective data from the case notes of elderly patients who had undergone total hip replacement. Inter-rater reliability was examined twice, first with two raters (n = 39) and then with three (n = 49). Intra-rater reliability was assessed using one rater (n = 45). Reasons for any lack of reliability were explored. The inter-rater reliability of the ICED was moderate (kappa 0.5-0.6). While the Functional Severity index performed well (kappa 0.6-1.0), the Index of Disease Severity subindex was less reliable (kappa 0.4-0.5). Differences between raters had an impact on the observed association between comorbidity and serious post-operative complications. Intra-rater reliability was excellent (kappa 0.9). Several reasons why inter-rater reliability was only moderate were identified, mostly related to uncertainties in applying the ICED. The reliability of the ICED needs to be improved before it is used more widely with retrospective data. This might be achieved by further clarification of the instructions for its use.

Spatial orientation of the alpha and betac receptor chain binding sites on monomeric human interleukin-5 constructs

Interleukin-5 (IL-5), a disulfide-linked homodimer, can be induced to fold as a biological active monomer by extending the loop between its third and fourth helices (Dickason, R. R., and Huston, D. P. (1996) Nature 379, 652-655). We have designed eight monomeric IL-5 proteins to optimize biological activity and stability of the monomer. This was achieved by (i) inserting the joining loop at three different positions, (ii) by introducing an additional intramolecular disulfide bridge onto these backbones, and (iii) by creating circular permutations to fix the position of the carboxyl-terminal helix relative to the three other helices. The proteins dimerize with Kd values ranging from 20 to 200 microM and are therefore monomeric at the picomolar concentrations where they are biologically active. Introduction of a second disulfide confers increased stability, but this increased rigidity results in lower activity of the protein. Contrary to wild type IL-5, mutation of the betac contact residue on the first helix, Glu12, to Lys, into the circularly permutated constructs, did not abolish TF-1 proliferative and eosinophil activation activities. These results indicate that activation of the IL-5 receptor complex is not mediated solely by Glu12 on the first helix, and alternative mechanisms are discussed.

Base transitions dominate the mutational spectrum of a transgenic reporter gene in MSH2 deficient mice

Tumors derived from individuals with hereditary nonpolyposis colorectal cancer syndrome frequently demonstrate mutations in both alleles of hMSH2, a key gene in DNA mismatch repair (MMR). Sporadic tumors also frequently exhibit MMR deficiency. In keeping with the role of MMR in the maintenance of genome integrity, mice deficient in MSH2 via gene targeting demonstrate a high incidence of thymic lymphomas and small intestinal adenocarcinomas. To investigate the effects of MSH2 deficiency in normal tissues, mice containing a retrievable transgenic lacI reporter gene for mutation detection were crossed with MSH2-/- mice. Mice homozygous for MSH2 deficiency revealed 4.8, 11.0 and 15.2-fold elevations in spontaneous mutation frequency in DNA obtained from brain, small intestine, and thymus, respectively, as compared to heterozygous or wild-type mice. Mutations most frequently recovered from MSH2-/- mice were single base substitutions (77%), particularly base transitions (64%). Frameshifts occurred less frequently (19%) and fell within very short (3-5 bp) mononucleotide runs. Thus the number of key growth control genes potentially impacted by MMR deficiency extends beyond those containing repetitive sequences. These results highlight the capacity for MSH2 deficiency to serve as a potent driving force during the multi-step evolution of tumors.

An interleukin 5 mutant distinguishes between two functional responses in human eosinophils

Interleukin 5 (IL-5) is the key cytokine involved in regulating the production and many of the specialized functions of mature eosinophils including priming, adhesion, and survival. We have generated a point mutant of human IL-5, IL-5 (E12K), which is devoid of agonist activity in both a TF-1 cell proliferation assay and a human eosinophil adhesion assay. However, IL-5 (E12K) is a potent and specific antagonist of both these IL-5-dependent functional responses. In both receptor binding and cross-linking studies the wild-type and IL-5 (E12K) mutant exhibit virtually identical properties. This mutant protein was unable to stimulate tyrosine phosphorylation in human eosinophils, and blocked the phosphorylation stimulated by IL-5. In contrast, IL-5 (E12K) is a full agonist in a human eosinophil survival assay, although with reduced potency compared to the wild-type protein. This IL-5 mutant enables us to clearly distinguish between two IL-5-dependent functional responses and reveals distinct mechanisms of receptor/cellular activation.

The carboxy-terminal region of human interleukin-5 is essential for maintenance of tertiary structure but not for dimerization

The C-terminal region of interleukin-5 has previously been suggested to be important for biological activity [Mackenzie et al., (1991), Mol. Immunol. 28, 155-158; Kodama et al. (1991), Biochem. Biophys. Res. Commun. 178, 514-519]. We have investigated this region by making a series of truncation mutants. The proteins were expressed in Escherichia coli, purified from inclusion bodies, and were able to refold with the disulfide homodimeric topology typical of interleukin-5. Analysis of the truncated carboxy-terminal proteins in an interleukin-5-dependent proliferation assay on TF-1 cells showed a rapid loss of activity as the C-terminal was shortened by more than two amino acids. This loss of biological activity correlated with a drop in binding affinity to both the alpha chain of the receptor and the high-affinity complex consisting of the alpha and beta subunits. Analysis of the proteins by 1H-NMR showed that the truncated mutants have higher exchange rates with solvent, indicating a less rigid structure. The carboxy-terminal region is therefore necessary to maintain the stability of the four-helix bundle and to orient correctly the important residues of the fourth helix. Inspection of the structure determined by X-ray crystallography shows that Trp-110 acts as the major residue in anchoring the fourth helix.

Soluble interleukin-5 receptor alpha-chain binding assays: use for screening and analysis of interleukin-5 mutants

Interleukin-5 (IL-5) is a key cytokine for the production, differentiation, and activation of eosinophils. IL-5 is a member of the four helical bundle family of cytokines, and in common with many members of the cytokine family it binds to a heterodimeric receptor composed of a ligand binding alpha-chain and a signal-transducing beta-chain. We have established two receptor/ligand binding assays based on the extracellular domain of the receptor alpha-chain which we have produced as a fusion protein. One assay is based on scintillation proximity fluoromicrospheres and radiolabeled ligand and the other on detection of biotinylated ligand binding to immobilized receptor using a chemiluminescent substrate in a 96-well microtiter plate format. Both receptor binding assays have been optimized for high throughput screening for receptor antagonists. These assays were also used for analytical purposes and the binding of ligand to the receptor alpha-chain was compared directly to receptor binding assays performed on TF-1 cells which express the receptor alpha beta-heterodimer. These three assays have been used to study site-directed mutants of IL-5 to determine the important residues for interaction of the cytokine with each chain of the receptor (P. Graber et al. (1995) J. Biol. Chem. 270, 15762-15769).

Identification of key charged residues of human interleukin-5 in receptor binding and cellular activation

Interleukin-5 (IL-5) is a cytokine that plays a major role in the differentiation and activation of eosinophils. In order to identify which charged residues of human IL-5 are important in binding to its receptor and subsequent cellular activation, we have systematically replaced all of the clusters of charged amino acids with alanine residues. The mutants have been expressed in Escherichia coli, renatured, and purified. They were assayed for ability to cause proliferation of the erythroleukaemic cell line TF-1 and the up-regulation of eosinophil adhesion to ICAM-1. In addition, we studied receptor binding using either immobilized recombinant IL-5 receptor alpha-chain or the alpha/beta-receptor complex expressed on TF-1 cells. The key charged residue involved in binding to the beta-chain of the receptor is Glu-12. This residue is in an identical position to those previously identified in IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) involved in binding to the receptor beta-chain. The alpha-chain binding site is shown to involve the side chains Arg-90 and Glu-109, located in the second beta sheet and after the end of the fourth helix, respectively. It is unique to IL-5 and does not occur in IL-3 or GM-CSF. Understanding the topology of the interaction of IL-5 with its receptor chains will help in the search for rationally designed antagonists of IL-5 function.

Does the Hawksley random zero sphygmomanometer underestimate blood pressure, and by how much?

The study objective was to compare blood pressure (BP) measurement by the Hawksley random-zero sphygmomanometer and the standard mercury sphygmomanometer. Comparison of simultaneous 'blind' BP measurements were made using the Hawksley random-zero sphygmomanometer and the standard mercury sphygmomanometer linked by a Y-connector to a single cuff, in the general practice and office environments. Sixty five healthy volunteers and general practice patients, aged between 20 and 50 years (SBP range 82-184 mm Hg, DBP range 38-112 mm Hg), were studied. Each had three blood pressure measurements taken. Mean BPs recorded by the Hawksley random-zero sphygmomanometer were lower than those recorded by the standard mercury sphygmomanometer. The Hawksley random-zero sphygmomanometer underestimated SBP by 1.3 mm Hg (95% CI 0.9-1.8 mm Hg) and DBP by 1.7 mm Hg (95% CI 1.1-2.3 mm Hg). These differences between instruments were independent of BP level both for systolic and diastolic measurements. An overview including this study and six other published reports describing nine studies examining the performance of the Hawksley random-zero sphygmomanometer suggested a similar degree of underestimation for SBP (mean difference 1.35 mm Hg, 95% CI 1.24-1.46 mm Hg). Underestimation of DBP appeared greater (mean difference 2.54 mm Hg, 95% CI 2.43-2.65 mm Hg) but was reduced when two outlying studies were removed from analysis (mean 1.97, 95% CI 1.85-2.09 mm Hg). We conclude that the Hawksley random-zero sphygmomanometer underestimates systolic and diastolic pressure, when compared with the standard mercury sphygmomanometer. However, the degree of underestimation is small and appears consistent across a wide range of blood pressure levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Hospital admissions and social deprivation of patients with diabetes mellitus

This study examined the relationship between hospital admissions for patients with diabetes mellitus and residence in an area of social deprivation. Admissions of patients with diabetes mellitus were identified during a 5-year period between 1987 and 1992 using the district patient information service. All persons admitted were assigned to an electoral ward on the basis of their postcode. Age standardized admission rates were compared to the Townsend Deprivation Score for each electoral ward. A positive correlation was found between age standardized admission rate and Townsend Score (r = 0.76, p < 0.001). We believe this has significance for planning health care resources.

An approach to manageable datasets in diabetes care. British Diabetic Association

A proposal is made to help the implementation of the British Diabetic Association dataset for diabetes care in those sites of care where information technology has yet to be established, or is in need of modification. A stepped approach is suggested and priorities identified.

Phospholipase-D activation can be negatively regulated through the action of protein kinase C

Transient activation of COS-1 cell phospholipase-D (PLD) in response to the protein kinase C (PKC) agonist tetradecanoyl phorbol acetate (TPA) was demonstrated by monitoring the ethanol-dependent accumulation of phosphatidylethanol (PtdEth). Transfection of COS-1 cells with PKC-alpha (wild type and constitutively activated mutants) produced no detectable ptdEth on incubation of transfected cells in the presence of ethanol. However, the response of transfected cells to subsequent TPA stimulation was inhibited, consistent with a role for the PKC-alpha in the suppression of PLD activity.

A comparison of demethoxyviridin and wortmannin as inhibitors of phosphatidylinositol 3-kinase

The mammalian Ptdlns 3-kinase is shown to be inhibited by low nanomolar concentrations of demethoxyviridin, an antifungal agent structurally related to wortmannin. The inhibitory potency of both compounds could be observed in purified Ptdlns 3-kinase whether or not the regulatory subunit (p85 alpha) was present, suggesting that the inhibitors bind to the catalytic subunit (p110) of the Ptdlns 3-kinase. These inhibitors also show similar potency against the intrinsic p85-phosphorylating activity of the p110-kinase. However, the structurally related Ptdlns 3-kinase from Saccharomyces cerevisiae (Vps34p) is not inhibited by either compound. Both inhibitors target the mammalian Ptdlns 3-kinase in vitro and in vivo, implying that these compounds should be useful in suppressing Ptdlns 3-kinase in mammalian systems. The inhibitors did not affect the mammalian Ptdlns 4-kinase, but they are able to inhibit a membrane-associated Ptdlns 4-kinase from Schizosaccharomyces pombe.

Midline cervical cleft

Midline cervical cleft is a rare congenital anomaly of the ventral neck. A series of 12 cases of midline cervical clefts over a 30-year period is reported. This anomaly is part of a spectrum of midline branchiogenic syndromes resulting from abnormal migration of cells derived from the branchial arches. The preferred operative correction requires complete excision of the cleft with its underlying fibrous cord and closure with multiple Z-plasties.

Geographic distribution of peptic ulcer disease in Western Samoa

A survey of peptic ulcer disease in Western Samoa is described. As compared with New Zealand experience, an unusually high prevalence of peptic ulceration is documented. A remarkable and significant variation in the geographic distribution of cases is reported. Regions of high prevalence were significantly associated with disease onset at an earlier age and with increased frequency of a family history of ulcer disease. It is concluded that this genetic predisposition is unlikely to sufficiently account for the regional localisation of cases observed and environmental causes are under study.