Genotoxic effects of high-energy iron particles in human lymphoblasts differing in radiation sensitivity

The effects of (56)Fe particles and (137)Cs gamma radiation were compared in TK6 and WTK1 human lymphoblasts, two related cell lines which differ in TP53 status and in the ability to rejoin DNA double-strand breaks. Both cell lines were more sensitive to the cytotoxic and clastogenic effects of (56)Fe particles than to those of gamma rays. However, the mutagenicity of (56)Fe particles and gamma rays at the TK locus was the same per unit dose and was higher for gamma rays than for (56)Fe particles at isotoxic doses. The respective RBEs for TK6 and WTK1 cells were 1.5 and 1.9 for cytotoxicity and 2.5 and 1.9 for clastogenicity, but only 1 for mutagenicity. The results indicate that complex lesions induced by (56)Fe particles are repaired less efficiently than gamma-ray-induced lesions, leading to fewer colony-forming cells, a slightly higher proportion of aberrant cells at the first division, and a lower frequency of viable mutants at isotoxic doses. WTK1 cells (mutant TP53) were more resistant to the cytotoxic effects of both gamma rays and (56)Fe particles, but showed greater cytogenetic and mutagenic damage than TK6 cells (TP53(+)). A deficiency in the number of damaged TK6 cells (a) reaching the first mitosis after exposure and (b) forming viable mutants can explain these results.

Inhibition of hepatitis B virus DNA replication by imino sugars without the inhibition of the DNA polymerase: therapeutic implications

Previously we have shown that the imino sugar inhibitor of N-linked glycan processing, N-nonyl-deoxynojirimycin (N-nonyl-DNJ), had antiviral activity in the woodchuck model of chronic hepatitis B virus (HBV) infection. In studying the mechanism of action of this compound, it was discovered that imino sugars could inhibit HBV secretion without inhibiting N-linked glycoprocessing. Although N-nonyl-DNJ is an inhibitor of the endoplasmic reticulum (ER) glucosidase, here it is shown that N-nonyl-DNJ retained antiviral activity at concentrations that had no significant impact on ER glucosidase function. Taken together, these results suggested that N-nonyl-DNJ possessed an antiviral activity attributable to a function other than an impact on glycoprocessing. This hypothesis was confirmed by experiments showing that N-nonyl-deoxygalactojirimycin (N-nonyl-DGJ), an alkyl derivative of galactose with no impact on glycoprocessing, retains anti-HBV activity. The data suggest that N-nonyl-DGJ exerts its antiviral action at a point before viral envelopment and may prevent the proper encapsidation of the HBV pregenomic RNA.

Skp2 is oncogenic and overexpressed in human cancers

Skp2 is a member of the F-box family of substrate-recognition subunits of SCF ubiquitin-protein ligase complexes that has been implicated in the ubiquitin-mediated degradation of several key regulators of mammalian G(1) progression, including the cyclin-dependent kinase inhibitor p27, a dosage-dependent tumor suppressor protein. In this study, we examined Skp2 and p27 protein expression by immunohistochemistry in normal oral epithelium and in different stages of malignant oral cancer progression, including dysplasia and oral squamous cell carcinoma. We found that increased levels of Skp2 protein are associated with reduced p27 in a subset of oral epithelial dysplasias and carcinomas compared with normal epithelial controls. Tumors with high Skp2 (>20% positive cells) expression invariably showed reduced or absent p27 and tumors with high p27 (>20% positive cells) expression rarely showed Skp2 positivity. Increased Skp2 protein levels were not always correlated with increased cell proliferation (assayed by Ki-67 staining), suggesting that alterations of Skp2 may contribute to the malignant phenotype without affecting proliferation. Skp2 protein overexpression may lead to accelerated p27 proteolysis and contribute to malignant progression from dysplasia to oral epithelial carcinoma. Moreover, we also demonstrate that Skp2 has oncogenic potential by showing that Skp2 cooperates with H-Ras(G12V) to malignantly transform primary rodent fibroblasts as scored by colony formation in soft agar and tumor formation in nude mice. The observations that Skp2 can mediate transformation and is up-regulated during oral epithelial carcinogenesis support a role for Skp2 as a protooncogene in human tumors.

TP53-dependent chromosome instability is associated with transient reductions in telomere length in immortal telomerase-positive cell lines

Telomere shortening in telomerase-negative somatic cells leads to the activation of the TP53 protein and the elimination of potentially unstable cells. We examined the effect of TP53 gene expression on both telomere metabolism and chromosome stability in immortal, telomerase-positive cell lines. Telomere length, telomerase activity, and chromosome instability were measured in multiple clones isolated from three related human B-lymphoblast cell lines that vary in TP53 expression; TK6 cells express wild-type TP53, WTK1 cells overexpress a mutant form of TP53, and NH32 cells express no TP53 protein. Clonal variations in both telomere length and chromosome stability were observed, and shorter telomeres were associated with higher levels of chromosome instability. The shortest telomeres were found in WTK1- and NH32-derived cells, and these cells had 5- to 10-fold higher levels of chromosome instability. The primary marker of instability was the presence of dicentric chromosomes. Aneuploidy and other stable chromosome alterations were also found in clones showing high levels of dicentrics. Polyploidy was found only in WTK1-derived cells. Both telomere length and chromosome instability fluctuated in the different cell populations with time in culture, presumably as unstable cells and cells with short telomeres were eliminated from the growing population. Our results suggest that transient reductions in telomere lengths may be common in immortal cell lines and that these alterations in telomere metabolism can have a profound effect on chromosome stability.

Cytomegalovirus maculopapular eruption in a kidney transplant patient

Cytomegalovirus (CMV) is the most important viral agent in kidney transplantation. Clinical manifestations of CMV disease in transplantation include hepatitis, pneumonitis, pancreatitis, kidney allograft dysfunction, colitis, and meningoencephalitis. However, skin involvement is rare. We describe a severely compromised cadaveric-kidney transplant recipient who developed renal failure, colonic ulcers, and a maculopapular rash accompanied by fever and malaise 4 months after transplantation. Only the skin biopsy was diagnostic and consistent with CMV disease. Intravenous ganciclovir administration resulted in clinical improvement of CMV-induced skin lesions; kidney function normalized and the patient became asymptomatic after 14 days of ganciclovir therapy. Nephrologists should consider the diagnosis of CMV disease in the febrile immunosuppressed patient with skin involvement. Skin biopsy must be considered as a useful and safe procedure in patients with a rash to obtain a prompt diagnosis and efficiently treat this immunocompromised population.

Treatments for fatigue in multiple sclerosis: a rapid and systematic review

BACKGROUND

Multiple sclerosis (MS) is an important problem both for people with the disease and for society. There is no cure, and alleviation of symptoms forms the cornerstone of care. Excessive fatigue that severely limits activity is experienced by at least two-thirds of the estimated 60,000 people with MS in the UK.

OBJECTIVES

(1) To identify current treatments for fatigue in MS and their evidence-base. (2) To systematically review the evidence for those treatments that have been investigated in more than one rigorous study, in order to determine their effectiveness and cost-effectiveness.

METHODS

The review was carried out in two stages: a formal scoping review (to assess the range of interventions used by people with MS), and a systematic review for treatments that had been identified as promising and that had been investigated in clinical trials (as identified in the scoping review). A systematic review of research on costs and cost-effectiveness of those interventions identified as promising was also performed. Electronic databases, including MEDLINE and EMBASE, were searched for the period 1991-June 1999 (scoping review) and 1966-December 1999 (systematic review). Reference lists from publications were also searched, and experts were contacted for any additional information not already identified.

RESULTS

Interventions identified for the treatment of fatigue in MS (1) Behavioural advice. This is the main element of initial clinical management and no rigorous research of its effectiveness was identified. (2) Drugs (amantadine, pemoline, potassium-channel blockers and antidepressants). (3) Training, rehabilitation and devices (cooling vests and electromagnetic fields). (4) Alternative therapies (bee venom, cannabis, acupuncture/acupressure and yoga). Only two drugs, amantadine and pemoline, met the criteria for full systematic review. RESULTS - EFFECTIVENESS OF AMANTADINE: One parallel and three crossover trials were found, involving a total of 236 people with MS. All studies were open to bias. All studies showed a pattern in favour of amantadine compared with placebo, but there is considerable uncertainty about the validity and clinical significance of this finding. This pattern of benefit was considerably undermined when different assumptions were used in the sensitivity analysis. RESULTS - EFFECTIVENESS OF PEMOLINE: One parallel and one crossover trial were found involving a total of 126 people with MS. Both studies were open to bias. There was no overall tendency in favour of pemoline over placebo and an excess of reports of adverse effects with pemoline. RESULTS - HEALTH ECONOMIC ANALYSIS: The drug costs of amantadine and pemoline are modest (pound 200 and pound 80 per annum, respectively). No economic evaluations were identified in the systematic review, and available data were insufficient to allow modelling of cost-effectiveness in this rapid review.

CONCLUSIONS

There is insufficient evidence to allow people with MS, clinicians or policy makers to make informed decisions on the appropriate use of the many treatments on offer. Only amantadine appears to have some proven ability to alleviate the fatigue in MS, though only a proportion of users will obtain benefit and then only some of these patients will benefit sufficiently to take the drug in the long term. CONCLUSIONS - RECOMMENDATIONS FOR RESEARCH: The frequency, severity and impact of fatigue, the poverty of available research, and the absence of any ongoing research, suggest that new research is an urgent priority. People with MS, clinicians and policy makers should work together to ensure that the evidence required is collected as quickly as possible by encouraging involvement in rigorous research. Research should not be restricted to the two drugs reviewed in depth in this report. All interventions identified in the scoping review (see above) should be considered, as should basic scientific research into the underlying mechanism of fatigue in MS.

A role for chromosomal instability in the development of and selection for radioresistant cell variants

Chromosome instability is a common occurrence in tumour cells. We examined the hypothesis that the elevated rate of mutation formation in unstable cells can lead to the development of clones of cells that are resistant to the cancer therapy. To test this hypothesis, we compared chromosome instability to radiation sensitivity in 30 independently isolated clones of GM10115 human-hamster hybrid cells. There was a broader distribution of radiosensitivity and a higher mean SF(2)in chromosomally unstable clones. Cytogenetic and DNA double-strand break rejoining assays suggest that sensitivity was a function of DNA repair efficiency. In the unstable population, the more radioresistant clones also had significantly lower plating efficiencies. These observations suggest that chromosome instability in GM10115 cells can lead to the development of cell variants that are more resistant to radiation. In addition, these results suggest that the process of chromosome breakage and recombination that accompanies chromosome instability might provide some selective pressure for more radioresistant variants.

An exploratory investigation into the nursing management of aggression in acute psychiatric settings

The management of aggression in inpatient psychiatric facilities is a major concern for nurses. Despite the prevalence of research on aggression within psychiatric settings, very few studies have tracked the clinical management of identified patients in a systematic manner. The overall aim of this study was to explore the clinical management of patients identified as potentially aggressive in psychiatric inpatient settings. A multimethod approach was used to collect the data. This included surveys, focus groups, and a file audit of patients identified from a random sample of completed aggression incident forms. The findings indicated that 88% of nurses who participated in the survey were assaulted and indicated the need for risk assessment; team management and review; and the importance of the first 5 days of admission as crucial for assessment and review. The development of support structures, formal preceptoring and supervisory arrangements and postincident supports were suggested as part of an overall strategy to support nurses working in acute inpatient settings.

The effectiveness of the levonorgestrel-releasing intrauterine system in menorrhagia: a systematic review

OBJECTIVE

To determine whether the levonorgestrel-releasing intrauterine device (LNG-IUS), licensed at present for contraceptive use, may reduce menstrual blood loss with few side effects. If effective, surgery could be avoided with consequent resource savings.

METHODS

A systematic review addressing the effectiveness and cost effectiveness of the LNG-IUS for menorrhagia was undertaken.

RESULTS

Five controlled trials and five case series were found which measured menstrual blood loss. Nine studies recorded statistically significant average menstrual blood loss reductions with LNG-IUS (range 74%-97%). Another showed reduction in menstrual disturbance score. The LNG-IUS was more effective than tranexamic acid, but slightly less effective than endometrial resection at reducing menstrual blood loss. In one study, 64% of women cancelled surgery at six months, compared with 14% of control group women. In another, 82% were taken off surgical waiting lists at one year. No cost effectiveness studies were found.

DISCUSSION

Small studies of moderate quality indicate the LNG-IUS is an effective treatment for menorrhagia. Costs may be less than for tranexamic acid in primary and secondary care. Although its use may reduce surgical waiting lists, cost effectiveness assessment requires longer follow up.

CONCLUSION

Effectiveness and cost effectiveness relative to other treatments and the effect on surgical waiting lists can only be established in larger trials measuring patient-centred outcomes in women with menorrhagia.

The Rate constant of the Reaction of OH(A2Σ+) with H2O2(X˜1A)

The rate constant of the depletion of OH radicals in the first electronically excited state with hydrogenperoxid:

Mutagen sensitivity as an indicator of soft tissue sarcoma risk

The etiology of soft tissue sarcoma is poorly understood. Exposure to environmental chemicals may play a role, but the data are not clear. We compared a group of soft tissue sarcoma patients with healthy controls to determine whether the mutagen sensitivity assay, a simple chromosome aberration assay using the radiomimetic bleomycin, might be useful to identify patients at risk for soft tissue sarcoma. Patients with a diagnosis of soft tissue sarcoma at Memorial Sloan-Kettering's outpatient clinic signed informed consent and donated 30 ml of blood. Controls were selected from the general population of Connecticut by random digit dialing. Unrepaired DNA damage was assessed for 100 metaphase spreads for each individual, with the number of breaks in chromatids being counted as breaks per cell (b/c). The 20 cases with soft tissue sarcoma had 1.03 mean b/c and the controls had 0.88 b/c (P = 0.16). Patients with soft tissue sarcoma were 5.7 times more likely to be mutagen sensitive than controls (P = 0.01), as determined after dividing subjects into sensitive or not sensitive groups based on the median b/c among controls. As mutagen sensitivity has been shown to be associated with a number of cancers and appears to reflect genetic susceptibility, this assay may be an appropriate biomarker for radiation sensitivity or it may be a marker of susceptibility to soft tissue sarcoma. Larger studies should be undertaken to assess these possibilities.

Influence of the axial ligands on the spectral properties of P700 of photosystem I: a study of site-directed mutants

Two histidines provide the axial ligands of the two chlorophyll a (Chl a) molecules which form the primary electron donor (P700) of photosystem I (PSI). Histidine 676 in the protein subunit PsaA, His(A676), and histidine 656 in subunit PsaB, His(B656), were replaced in the green algae Chlamydomnas reinhardtii by site-directed mutagenesis with nonpolar, uncharged polar, acidic, and basic amino acid residues. Only the substitutions with uncharged polar residues led to a significant accumulation of PSI in the thylakoid membranes. These PSI complexes were isolated and the physical properties of the primary donor characterized. The midpoint potential of P700(+)(*)/P700 was increased in all mutants (up to 140 mV) and showed a dependence on size and polarizability of the residues when His(B656) was substituted. In the light-minus-dark absorbance spectra, all mutations in PsaB exhibited an additional bleaching band at 665 nm at room temperature comparable with the published spectrum for the replacement of His(B656) with asparagine [Webber, A. N., Su Hui, Bingham, S. E., Käss, H., Krabben, L., Kuhn, M., Jordan, R., Schlodder, E., and Lubitz, W. (1996) Biochemistry 35, 12857-12863]. Substitutions of His(A676) showed an additional shoulder around 680 nm. In the low-temperature absorbance difference spectra of P700(+)(*)/P700, a blue shift of the main bleaching band by 2 nm and some changes in the spectral features around 660 nm were observed for mutations of His(B656) in PsaB. The analogous substitution in PsaA showed only a shift of the main bleaching band. Similar effects of the mutations were found in the (3)P700/P700 absorbance difference spectra at low temperatures (T = 2 K). The zero-field splitting parameters of (3)P700 were not significantly changed in the mutated PSI complexes. The electron spin density distribution of P700(+)(*), determined by ENDOR spectroscopy, was only changed when His(B656) was replaced. In all measurements, two general observations were made. (i) The replacement of His(B656) had a much stronger impact on the physical properties of P700 than the mutation of His(A676). (ii) The exchange of His(B656) with glutamine induces the smallest changes in the spectra or the midpoint potential, whereas the other replacements exhibited a stronger but very similar influence on the spectroscopic features of P700. The data provide convincing evidence that the unpaired electron in the cation radical and the triplet state of P700 are mainly localized on the Chl a of the dimer which is axially coordinated by His(B656).

Self-assembled monolayers of rigid thiols

The preparation, structure, properties and applications of self-assembled monolayers (SAMs) of rigid 4-mercapto-biphenyls are briefly reviewed. The rigid character of the biphenyl moiety results in a molecular dipole moment that affects both the adsorption kinetics on gold surfaces, as well as the equilibrium structure of mixed SAMs. Due to repulsive intermolecular interaction, the Langmuir isotherm model does not fit the adsorption kinetics of these biphenyl thiols, and a new Ising model was developed to fit the kinetics data. The equilibrium structures of SAMs and mixed SAMs depend on the polarity of the solution from which they were assembled. Infrared spectroscopy suggests that biphenyl moieties in SAMs on gold have small tilt angles with respect to the surfaces normal. Wetting studies shows that surfaces of these SAMs are stable for months, thus providing stable model surfaces that can be engineered at the molecular level. Such molecular engineering is important for nucleation and growth studies. The morphology of glycine crystals grown on SAM surfaces depends on the structure of the nucleating glycine layer, which, in turn, depends on the H-bonding of these molecules with the SAM surface. Finally, the adhesion of PDMS cross-linked networks to SAM surfaces depends on the concentration of interfacial H-bonding. This non-linear relationship suggests that the polymeric nature of the elastomer results in a collective H-bonding effect.

Evidence for the expression of radiation-induced potentially lethal damage being a p53-dependent process

PURPOSE

To test the hypothesis that the expression of potentially lethal damage (PLD) is a p53-dependent process.

MATERIALS AND METHODS

Previously reported data on radiation sensitivity, DNA double-strand break rejoining, PLD expression and repair (PLDR) were analyzed for a group of 12 human tumor cell lines and three human diploid fibroblast cell lines. Seven of these cell lines had normal p53 gene expression while the other eight were functionally p53-deficient. None of the cell lines was sensitive to radiation-induced apoptosis.

RESULTS

Cell lines with a normal p53 expression were more sensitive to radiation, but only when sensitivity was measured in plateau-phase cultures under conditions where PLDR was minimized. Mutation or functional inactivation of p53 by HPV E6-transformation led to a more radioresistant phenotype under these conditions as well as a significant reduction in PLDR. PLDR was inversely proportional to the percentage of radiation-induced DNA double-strand breaks rejoined in 1 h in the p53 normal cell lines.

CONCLUSIONS

These results suggest that the expression of PLD is primarily a p53-dependent process. In the absence of functional p53 gene expression, the effects of PLD are minimized. These observations help clarify the role of p53 in tumor response to radiation therapy because they suggest that the effects of alterations in p53 are highly dependent on the microenvironment of the tumor, i.e. whether conditions allow for PLDR.

Circadian variation of cell proliferation and cell cycle protein expression in man: clinical implications

Most physiological, biochemical and behavioural processes have been shown to vary in a regular and predictable periodic manner with respect to time. This review focuses on the circadian rhythm in cell proliferation in bone marrow and gut and how this is associated with a circadian expression of cell cycle proteins in human oral mucosa. The control of circadian rhythms by the suprachiasmatic nuclei and the evolving understanding of the genetic and molecular biology of the circadian clock is outlined. Finally, the potential clinical impact of chronobiology in cancer medicine is discussed.

First photosystem II crystals capable of water oxidation

Oxygen evolution and proton release of crystallised photosystem II core complexes isolated from Synechococcus elongatus were measured. The yields show that the crystals themselves are capable of highly active water oxidation. This opens the possibility for the structural analysis of the outstanding water-oxidising apparatus.

Laser resurfacing of the skin for the improvement of facial acne scarring: a systematic review of the evidence

This review presents and evaluates the evidence of the effectiveness of laser resurfacing for facial acne scars. Primary studies of all types of design in any language were identified from MEDLINE, EMBASE, the Cochrane database, Science Citation Index and various internet sites. Studies were accepted if they included patients treated by any laser for atrophic or ice-pick acne scars. The quality of the studies was assessed and data extracted by two independent researchers. There were no controlled trials but 14 case series were found which reported the effects of either the carbon dioxide or erbium:YAG laser. All of the studies were of poor quality. The types and severity of scarring were poorly described and there was no standard scale used to measure scar improvement. There was no reliable or validated measure of patient satisfaction; most improvement was based on visual clinical judgement, in many cases without blinded assessment. The inaccurate use of ordinal scales meant that any improvement was impossible to quantify with any validity, although the evidence suggested that laser treatment had some efficacy (a range in individual patients of 25-90% for both the carbon dioxide laser and the erbium:YAG laser). Changes in pigmentation as a side-effect were common (in up to 44% of patients), although lasting only a few weeks. Laser resurfacing technology is increasingly used in clinical practice to treat acne scars. Despite the poor quality evidence, it is plausible that there is some improvement of acne scarring; there is insufficient information, however, for patients to make informed decisions on whether to opt for treatment and there is not enough evidence to compare the two types of laser. There is a particular lack of information about the psychological effects of acne scar improvement. Good quality randomized controlled trials are needed with standardized scarring scales and validated patient outcome measures in order to assess the effectiveness of laser resurfacing in this group of patients.

Dose-dependent changes in the spectrum of mutations induced by ionizing radiation

We examined the influence of dose on the spectrum of mutations induced at the hypoxanthine guanine phosphoribosyltransferase (Hprt) locus in Chinese hamster ovary (CHO) cells. Independent CHO-K1 cell mutants at the Hprt locus were isolated from cells exposed to 0, 0.5, 1.5, 3.0 and 6.0 Gy (137)Cs gamma rays, and the genetic changes responsible for the mutations were determined by multiplex polymerase chain reaction (PCR)-based exon deletion analysis. We observed dose-dependent changes in mutation spectra. At low doses, the principal radiation-induced mutations were point mutations. With increasing dose, multibase deletion mutations became the predominant mutation type such that by 6.0 Gy, there were almost three times more deletion mutations than point mutations. The dose response for induction of point mutations was linear while that for multibase deletions fit a linear-quadratic response. There was a biphasic distribution of deletion sizes, and different dose responses for small compared to large deletions. The frequency of large (>36 kb) total gene deletions increased exponentially, implying that they develop from the interaction between two independent events. In contrast, the dose response for deletion mutations of less than 10 kb was nearly linear, suggesting that these types of mutations develop mostly from single events and not the interactions between two independently produced lesions. The observation of dose-dependent changes in radiation-induced mutation spectra suggests that the types of alterations and therefore the risks from low-dose radiation exposure cannot be easily extrapolated from high-dose effects.

Self-organization in nonlinear wave turbulence

We present a statistical equilibrium model of self-organization in a class of focusing, nonintegrable nonlinear Schrodinger (NLS) equations. The theory predicts that the asymptotic-time behavior of the NLS system is characterized by the formation and persistence of a large-scale coherent solitary wave, which minimizes the Hamiltonian given the conserved particle number (L2-norm squared), coupled with small-scale random fluctuations, or radiation. The fluctuations account for the difference between the conserved value of the Hamiltonian and the Hamiltonian of the coherent state. The predictions of the statistical theory are tested against the results of direct numerical simulations of NLS, and excellent qualitative and quantitative agreement is demonstrated. In addition, a careful inspection of the numerical simulations reveals interesting features of the transitory dynamics leading up to the long-time statistical equilibrium state starting from a given initial condition. As time increases, the system investigates smaller and smaller scales, and it appears that at a given intermediate time after the coalescense of the soliton structures has ended, the system is nearly in statistical equilibrium over the modes that it has investigated up to that time.

Recall for self and other in autism: children's memory for events experienced by themselves and their peers

Research on memory processing suggests that memory for events that an individual experiences should be superior to that for similar events that someone else experiences (e.g., Baker-Ward et al., 1990). However, such predictions may not be applicable to individuals with autism. There are already suggestions that individuals with autism have specific difficulties in remembering (Boucher & Lewis, 1989). In addition, they are known to have more general difficulties involving processes related to the "self." If children with autism have difficulties in encoding information about themselves this could result in a deficit in personal episodic memory. The studies reported here compare memory for personally experienced events with that of memory for events experienced by a peer. An adaptation of a method devised by Boucher and Lewis has been employed to assess recall. Two separate studies were conducted to investigate whether children with autism are impaired at recalling personal events. Two groups of children took part in Study 1, a group of children with autism and a control group of typical children matched for verbal mental age. A group of children with moderate learning difficulties were employed in the second study to investigate whether the findings also occur in other groups of individuals who have learning disabilities. Findings indicate that, in the group with autism, events performed by the individual were recalled significantly less well than the observed events performed by a peer. However, the results for the nonautistic children in both studies showed that the opposite was true. Theoretical claims are discussed in the light of these findings.

Suicidal patients and special observation

Special observation is a nursing practice utilized in in-patient psychiatric facilities for patients who are suicidal. Special observation is carried out by an allocated registered nurse remaining continuously at arms length from, or within sight of (as specified), the patient; or a registered nurse observing the patient within a 30 min interval. In this exploratory study, we investigated the role of the registered nurse when caring for patients on special observation. Semistructured interviews were conducted with 10 randomly selected registered nurses from 4 acute psychiatric wards. The 9 themes that emerged were: 1) Safety; 2) Therapeutic relationships; 3) Supporting patients and carers; 4) Consequences of special observation for nurses; 5) Continuity of care concerns; 6) Peer support; 7) Suicide indicators; 8) Responsibilities and rights: nurses and patients; and 9) Nurses, doctors and the hospital hierarchy. Recommendations for alleviation of the concerns about the practice of special observation are outlined and discussed.