Characteristics and burden of acute COVID-19 and long-COVID: Demographic, physical, mental health, and economic perspectives

BACKGROUND

COVID-19 infection and its associated consequence, known as long-COVID, lead to a significant burden on the global healthcare system and limitations in people's personal and work lives. This study aims to provide further insight into the impact of acute and ongoing COVID-19 symptoms and investigates the role of patients' gender and vaccination status.

METHODS

416 individuals (73.9% female) between the ages of 16 and 80 years (M = 44.18, SD = 12.90) with self-reported symptoms of long-COVID participated in an online survey conducted between March and May 2022.

RESULTS

6.0%, 74.3%, and 19.7% of all respondents reported having had an asymptomatic, mild, or severe acute illness, respectively. Out of all participants, 7.8% required hospitalization. The most prevalent symptoms during the acute infection (Mdn = 23.50 symptoms, IQR = 13-39) included fatigue, exhaustion, cough, brain fog, and memory problems. The median long-COVID disease duration was 12.10 months (IQR = 2.8-17.4). Among 64 inquired long-COVID symptoms (Mdn = 17.00 symptoms, IQR = 9-27), participants reported fatigue, exhaustion, memory problems, brain fog, and dyspnea as the most common ongoing symptoms, which were generally experienced as fluctuating and deteriorating after physical or cognitive activity. Common consequences of long-COVID included financial losses (40.5%), changes in the participants' profession (41.0%), stress resistance (87.5%), sexual life (38.1%), and mood (72.1%), as well as breathing difficulties (41.3%), or an increased drug intake (e.g., medicine, alcohol; 44.6%). In addition, vaccinated individuals exhibited a shorter acute illness duration and an earlier onset of long-COVID symptoms. In general, women reported more long-COVID symptoms than men.

CONCLUSION

Long-COVID represents a heterogeneous disease and impacts multiple life aspects of those affected. Tailored rehabilitation programs targeting the plurality of physical and mental symptoms are needed.

Goal-directed fluid therapy using uncalibrated pulse contour analysis and balanced crystalloid solutions during hip revision arthroplasty: a quality implementation project

BACKGROUND

To implement a goal-directed fluid therapy (GDFT) protocol using crystalloids in hip revision arthroplasty surgery within a quality management project at a tertiary hospital using a monocentric, prospective observational study.

METHODS

Adult patients scheduled for elective hip revision arthroplasty surgery were screened for inclusion in this prospective study. Intraoperatively stroke volume (SV) was optimized within a previously published protocol using uncalibrated pulse contour analysis and balanced crystalloids. Quality of perioperative GDFT was assessed by protocol adherence, SV increase as well as the rate of perioperative complications. Findings were then compared to two different historical groups of a former trial: one receiving GDFT with colloids (prospective colloid group) and one standard fluid therapy (retrospective control group) throughout surgery. Statistical analysis constitutes exploratory data analyses and results are expressed as median with 25th and 75th percentiles, absolute and relative frequencies, and complication rates are further given with 95% confidence intervals for proportions using the normal approximation without continuity correction.

RESULTS

Sixty-six patients underwent GDFT using balanced crystalloids and were compared to 130 patients with GDFT using balanced colloids and 130 controls without GDFT fluid resuscitation. There was a comparable increase in SV (crystalloids: 65 (54-74 ml; colloids: 67.5 (60-75.25 ml) and total volume infused (crystalloids: 2575 (2000-4210) ml; colloids: 2435 (1760-3480) ml; and controls: 2210 (1658-3000) ml). Overall perioperative complications rates were similar (42.4% (95%CI 30.3-55.2%) for crystalloids and 49.2% (95%CI 40.4-58.1%) for colloids and lower compared to controls: 66.9% (95%CI 58.1-74.9)). Interestingly, a reduced number of hemorrhagic complications was observed within crystalloids: 30% (95%CI 19.6-42.9); colloids: 43% (95%CI 34.4-52.0); and controls: 62% (95%CI 52.6-69.9). There were no differences in the rate of admission to the post-anesthesia care unit or intensive care unit as well as the length of stay.

CONCLUSIONS

Perioperative fluid management using a GDFT protocol with crystalloids in hip revision arthroplasty surgery was successfully implemented in daily clinical routine. Perioperative complications rates were reduced compared to a previous management without GDFT and comparable when using colloids.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01753050.

European study confirms the combination of fever and petechial rash as an important warning sign for childhood sepsis and meningitis

AIM

This study investigated febrile children with petechial rashes who presented to European emergency departments (EDs) and investigated the role that mechanical causes played in diagnoses.

METHODS

Consecutive patients with fever presenting to EDs in 11 European emergency departments in 2017-2018 were enrolled. The cause and focus of infection were identified and a detailed analysis was performed on children with petechial rashes. The results are presented as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

We found that 453/34010 (1.3%) febrile children had petechial rashes. The focus of the infection included sepsis (10/453, 2.2%) and meningitis (14/453, 3.1%). Children with a petechial rash were more likely than other febrile children to have sepsis or meningitis (OR 8.5, 95% CI 5.3-13.1) and bacterial infections (OR 1.4, 95% CI 1.0-1.8) as well as need for immediate life-saving interventions (OR 6.6, 95% CI 4.4-9.5) and intensive care unit admissions (OR 6.5, 95% CI 3.0-12.5).

CONCLUSION

The combination of fever and petechial rash is still an important warning sign for childhood sepsis and meningitis. Ruling out coughing and/or vomiting was insufficient to safely identify low-risk patients.

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration

The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.

Effectiveness and Safety of an Intravenous Immune Globulin (IVIG) Preparation in Post-exposure Prophylaxis (PEP) Against Measles in Infants

Background: Administration of measles virus (MV)-specific IgG as post-exposure prophylaxis (PEP) is known to effectively prevent measles. Since the introduction of active immunization against measles, the levels of MV-specific IgG antibodies in the population have dropped. Therefore, the concentration of MV-specific antibodies in immunoglobulin products derived from human plasma donors has declined as the proportion of vaccinated donors has increased. Literature on the effectiveness of PEP with current available immunoglobulins is limited. Here we examine the effectiveness of 400 mg/kg intravenous immunoglobulin (IVIG) (IgVena®, Kendrion) as PEP in infants during a measles outbreak in Austria, 2019. Methods: After exposure to a highly contagious measles patient, identified infants were evaluated for eligibility for IVIG PEP. Infants were tested for measles maternal antibodies, if the result was expected to be available within 72 h after exposure. IVIG was administered to eligible infants with negative maternal IgG antibody levels (n = 11), infants with protective levels but result beyond 72 h (n = 2) and infants not tested for maternal IgG antibodies (n = 52). Telephone enquiries were made asking for measles infection. Effectiveness was calculated using exact logistic regression. Samples of four out of seven used IVIG batches were tested for MV-neutralizing antibody capacity. Results: In 63 (96.9%) of 65 infants PEP with IVIG was administered. The parents of two infants declined IVIG PEP. None of the infants with IVIG PEP got measles or symptoms suggestive for measles, but both infants who did not receive PEP were infected. Effectiveness of IVIG PEP was calculated to be 99.3% (CI 95%: 88.7-100%). No serious adverse event of IVIG treatment was observed. The investigation on MV-neutralizing antibody capacity showed a geometric mean titer ranging from 10.0 to 12.7 IU/ml, resulting in a 1.57-2.26-fold higher concentration than postulated as minimum level for immunity. Conclusions: Our findings suggest that the used IVIG preparation provided an at least non-inferior protection rate compared to IVIG preparations derived from donors before the global introduction of standard active immunization against measles.

Monitoring anticoagulation of primary haemostasis

This article provides an overview on current commercially available methods to determine primary haemostasis as a target of drug-mediated anticoagulation. It focuses on whole blood methods only, and references the currently major achievements that have been reported with each method in respect to its clinical use. Advantages and disadvantages of the various methods are presented, based on considerations of platelet physiology, and on feasibility of the procedures.

Gut microbiota dysbiosis associated with glucose metabolism disorders and the metabolic syndrome in older adults

Obesity and associated metabolic disorders have become highly prevalent diseases worldwide, and the human gut microbiota, due to its influence on host energy metabolism, has been attributed an important role therein. This pilot study explores host-microbiota relationships in men and women affected by various types of glucose metabolism disorder. Among 20 individuals aged 58 to 71 years with either normal glucose tolerance, prediabetes, or type 2 diabetes mellitus the gut bacterial communities were compared based on barcoded 454 sequencing of 16S rRNA genes amplified from stool samples. We found that specific microbiota groups were relatively enriched or reduced in different metabolic states. Further, positive or negative associations with clinical manifestations of metabolic disease suggest that these organisms indicate and possibly contribute to metabolic impairment or health. For instance, a higher prevalence of Erysipelotrichaceae and Lachnospiraceae was found associated with metabolic disorders, and the Holdemania and Blautia genera correlated with clinical indicators of an impaired lipid and glucose metabolism. The Bacteroidetes and groups therein, by contrast, displayed inverse relationships with metabolic disease parameters and were found relatively enriched in participants not diagnosed with metabolic syndrome or obesity. Further, the prevalence of specific Clostridia and Rikenellaceae members also pointed towards a healthier metabolic state. Links with diet as an intermediate factor included positive and negative associations of Lachnospiraceae with relative consumption rates of fat and carbohydrates, respectively, and positive associations of Turicibacteraceae with the consumption of protein. Identifying critical roles of major gut microbiota components in metabolic disorders has important translational implications regarding the prevention and treatment of metabolic diseases by means of preventing or reversing dysbiosis and by controlling exacerbating diet and life style factors particularly in sensitive population groups.

Isolation of Nocardia mexicana from focal proliferative tenosynovitis and arthritis in a steer

CASE REPORT

An 18-month-old Charolais steer was presented with lameness and fluctuant swelling of the right stifle joint, which yielded neutrophils on fine-needle aspiration. A diagnosis of bacterial proliferative tenosynovitis and arthritis was made on postmortem and histological examination. Culture and 16S rRNA sequencing identified a Nocardia sp. with 99% homology with the corresponding DNA fragment of N. mexicana DSM 44952. Antimicrobial susceptibility testing revealed the isolate was susceptible to co-trimoxazole and third-generation cephalosporins.

CONCLUSION

We report the first case, both in Australia and internationally, of proliferative tenosynovitis and arthritis caused by Nocardia spp. infection in a bovine and the first report of pathology attributed to N. mexicana in a veterinary patient. Given the limited susceptibility of the bacteria, the poor antimicrobial penetration that would be expected and the morphological changes that had taken place in the joint; the steer would have required protracted antimicrobial treatment in addition to invasive debridement of the lesion. This case emphasises the importance of routinely performing cytology and extended incubation of cultures in cases of arthritis in order to make ethical and economically viable treatment decisions.

A systematic review of risk assessment strategies for populations at high risk of engaging in violent behaviour: update 2002-8

BACKGROUND

This review systematically examines the research literature published in the period 2002-8 on structured violence risk assessment instruments designed for use in mental health services or the criminal justice system. It adopted much broader inclusion criteria than previous reviews in the same area in order to capture and summarise data on the widest possible range of available instruments.

OBJECTIVES

To address two questions: (1) what study characteristics are associated with a risk assessment instrument score being significantly associated with a violent outcome? and (2) which risk assessment instruments have the highest level of predictive validity for a violent outcome?

DATA SOURCES

Nineteen bibliographic databases were searched from January 2002 to April 2008, including PsycINFO, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, British Nursing Index, International Bibliography of the Social Sciences, Education Resources Information Centre, The Cochrane Library and Web of Knowledge.

REVIEW METHODS

Inclusion criteria for studies were (1) evaluation of a structured risk tool; (2) outcome measure of interpersonal violence; (3) participants aged 17 years or over; and (4) participants with a mental disorder and/or at least one offence and/or at least one indictable offence. A series of bivariate analyses using either a chi-squared test or Spearman's rank-order correlation were conducted to explore associations between study characteristics and outcomes. Data from a subset of studies reporting area under the curve (AUC) analysis were combined to provide estimates of mean validity.

RESULTS

For the overall set of included studies (n = 959), over three-quarters (77%) were conducted in the USA, Canada or the UK. Two-thirds of all studies were conducted with offenders who had either no formal mental health diagnosis (43%) or forensic samples with a formal diagnosis (25%). The Psychopathy Checklist-Revised was tested in the largest number of studies (n = 192). Most studies (78%) reported a statistically significant (p < 0.05) relationship between the instrument score and a violent outcome. Prospective data collection (chi-squared = 4.4, p = 0.035), number of people recruited (U = 27.8, p = 0.012) and number of participants at end point (U = 26.9, p = 0.04) were significantly associated with predictive validity. For those instruments tested in five or more studies reporting AUC values, the General Statistical Information on Recidivism instrument had the highest mean AUC (0.73).

LIMITATIONS

Agreement between pairs of reviewers in the initial pilot exercises was good but less than perfect, so discrepancies may be present given the complexity and subjectivity of some aspects of violence research. Only five of the seven calendar years (2003-7) are completely covered, with partial coverage of 2002 and 2008. There is no weighting for sample or effect sizes when results from studies are aggregated.

CONCLUSIONS

A very large number of studies examining the relationship between a structured instrument and a violent outcome were published in this relatively short 7-year period. The general quality of the literature is weak in places (e.g. over-reliance on cross-sectional designs) and a vast range of distinct instruments have been tested to varying degrees. However, there is evidence of some convergence around a small number of high-performing instruments and identification of the components of a high-quality evaluation approach, including AUC analysis. The upper limits (AUC ≥ 0.85) of instrument-based prediction have probably been achieved and are unlikely to be exceeded using instruments alone.

FUNDING

The National Institute for Health Research Health Technology Assessment and Research for Patient Benefit programmes.

Factor VIII Bypassing Activity (FEIBA) assays: standardization and development of the 1st NIBSC Working Standard for FEIBA--results from a collaborative study

Factor-Eight-Inhibitor-Bypassing-Activity (FEIBA) is a bypassing-agent used to control spontaneous bleeding or cover surgical interventions in Haemophiliacs who develop neutralizing antibodies against FVIII/FIX. The market lot-release of FEIBA is dependent on specific clot-based assays, carried out by both the manufacturer and regulatory authorities, relative to manufacturer's in-house standards, which are produced on a small-scale and are replaced frequently. We sought to standardize the FEIBA assay by developing a FEIBA primary standard which would be internationally available in sufficiently large quantities, with a predicted lifetime of many years. A collaborative study involving the manufacturer and three regulatory authorities, was carried out in which a candidate material, sample B (06/172), was calibrated by assays relative to the manufacturer's in-house FEIBA standards (C and D). All laboratories used their routine validated methods (16 APTT-assays, 8 ACTIN-FS-assays and 27 DAPTTIN-assays). Intra-laboratory geometric coefficients of variation (GCVs) for candidate B ranged from 3% to 29% (GCVs <9% from majority of labs). Assessment of inter-laboratory variability gave overall GCV values of 6.9% and 4.4% relative to standards C and D, respectively, for all methods. There was good agreement in potency estimation between laboratories using each of the three methods, with the overall potencies by the three methods differing by less than 10% of the overall mean, giving an overall combined potency of 28.0 units per ampoule. All participants agreed that candidate B (06/172) be established as the 1st NIBSC Working Standard for FEIBA with an assigned potency of 28.0 units per ampoule, based on combined results for both methods, relative to either standard C or D.

A systematic review of prevention and intervention strategies for populations at high risk of engaging in violent behaviour: update 2002-8

BACKGROUND

It has been estimated that violence accounts for more than 1.6 million deaths worldwide each year and these fatal assaults represent only a fraction of all assaults that actually occur. The problem has widespread consequences for the individual and for the wider society in physical, psychological, social and economic terms. A wide range of pharmacological, psychosocial and organisational interventions have been developed with the aim of addressing the problem. This review was designed to examine the effectiveness of these interventions when they are developed in mental health and criminal justice populations.

OBJECTIVE

To update a previous review that examined the evidence base up to 2002 for a wide range of pharmacological, psychosocial and organisational interventions aimed at reducing violence, and to identify the key variables associated with a significant reduction in violence.

DATA SOURCES

Nineteen bibliographic databases were searched from January 2002 to April 2008, including PsycINFO (CSA) MEDLINE (Ovid), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Allied and Complementary Medicine Database (AMED), British Nursing Index/Royal College of Nursing, International Bibliography of the Social Sciences (IBSS), Education Resources Information Center (ERIC)/International ERIC, The Cochrane Library (Cochrane reviews, other reviews, clinical trials, methods studies, technology assessments, economic evaluations), Web of Science [Science Citation Index Expanded (SCIE), Social Sciences Citation Index (SSCI), Arts & Humanities Citation Index (A&HCI)].

REVIEW METHODS

The assessment was carried out according to accepted procedures for conducting and reporting systematic reviews, including identification of studies, application of inclusion criteria, data extraction and appropriate analysis. Studies were included in meta-analyses (MAs) if they followed a randomised control trial (RCT) design and reported data that could be converted into odds ratios (ORs). For each MA, both a fixed-effects model and a random-effects model were fitted, and both Q statistic and I2 estimates of heterogeneity were performed.

RESULTS

A total of 198 studies were identified as meeting the inclusion criteria; of these, 51 (26%) were RCTs. Bivariate analyses exploring possible sources of variance in whether a study reported a statistically significant result or not, identified six variables with a significant association. An outcome was less likely to be positive if the primary intervention was something other than a psychological or pharmacological intervention, the study was conducted in an penal institution, the comparator was another active treatment or treatment as usual and if a between-groups design had been used. An outcome was more likely to be positive if it was conducted with people with a mental disorder. The variation attributable to these variables when added to a binary logistic regression was not large (Cox and Snell R(2) = 0.12), but not insignificant given the small number of variables included. The pooled results of all included RCTs suggested a statistically significant advantage for interventions over the various comparators [OR 0.59, 95% confidence interval (CI) 0.53 to 0.65, fixed effects; OR 0.35, 95% CI 0.26 to 0.49 random effects, 40 studies]. However, there was high heterogeneity {I(2) = 86, Q = 279 [degrees of freedom (df) = 39], p < 0.0001}, indicating the need for caution in interpreting the observed effect. Analysis by subgroups showed that most results followed a similar pattern, with statistically significant advantages of treatments over comparators being suggested in fixed- and/or random-effects models but in the context of large heterogeneity. Three exceptions were atypical antipsychotic drugs [OR 0.21, 95% CI 0.16 to 0.27, fixed effects; OR 0.24, 95% CI 0.14 to 0.43, random effects; 10 studies, I(2) = 72.2, Q = 32.4 (df = 9), p < 0.0001], psychological interventions [OR 0.63, 95% CI 0.48 to 0.83, fixed effects; OR 0.53, 95% CI 0.31 to 0.93, random effects; nine studies, I(2) = 62.1, Q = 21.1 (df = 8), p = 0.007] and cognitive behavioural therapy (CBT) as a primary intervention [OR 0.61, 95% CI 0.42 to 0.88, fixed effects; OR 0.61, 95% CI 0.37 to 0.99, random effects; seven studies, I(2) = 21.6, Q = 7.65 (df = 6), p = 0.26].

LIMITATIONS

The heterogenity of the included studies inhibits both robust MA and the clear application of findings to establishing improvements in clinical practice.

CONCLUSIONS

Results from this review show small-to-moderate effects for CBT, for all psychological interventions combined, and larger effects for atypical antipsychotic drugs, with relatively low heterogeneity. There is also evidence that interventions targeted at mental health populations, and particularly male groups in community settings, are well supported, as they are more likely to achieve stronger effects than interventions with the other groups. Future work should focus on improving the quality of evidence available and should address the issue of heterogenity in the literature.

FUNDING

The National Institute for Health Research Health Technology Assessment programme and the Research for Patient Benefit programme.

Near Field Communication-based telemonitoring with integrated ECG recordings

OBJECTIVES

Telemonitoring of vital signs is an established option in treatment of patients with chronic heart failure (CHF). In order to allow for early detection of atrial fibrillation (AF) which is highly prevalent in the CHF population telemonitoring programs should include electrocardiogram (ECG) signals. It was therefore the aim to extend our current home monitoring system based on mobile phones and Near Field Communication technology (NFC) to enable patients acquiring their ECG signals autonomously in an easy-to-use way.

METHODS

We prototypically developed a sensing device for the concurrent acquisition of blood pressure and ECG signals. The design of the device equipped with NFC technology and Bluetooth allowed for intuitive interaction with a mobile phone based patient terminal. This ECG monitoring system was evaluated in the course of a clinical pilot trial to assess the system's technical feasibility, usability and patient's adherence to twice daily usage.

RESULTS

21 patients (4f, 54 ± 14 years) suffering from CHF were included in the study and were asked to transmit two ECG recordings per day via the telemonitoring system autonomously over a monitoring period of seven days. One patient dropped out from the study. 211 data sets were transmitted over a cumulative monitoring period of 140 days (overall adherence rate 82.2%). 55% and 8% of the transmitted ECG signals were sufficient for ventricular and atrial rhythm assessment, respectively.

CONCLUSIONS

Although ECG signal quality has to be improved for better AF detection the developed communication design of joining Bluetooth and NFC technology in our telemonitoring system allows for ambulatory ECG acquisition with high adherence rates and system usability in heart failure patients.

The third generation superconducting 28 GHz electron cyclotron resonance ion source VENUS (invited)

VENUS is a third generation electron cyclotron resonance (ECR) ion source, which incorporates a high field superconducting NbTi magnet structure, a 28 GHz gryotron microwave source and a state of the art closed cycle cryosystem. During the decade from initial concept to regular operation, it has demonstrated both the feasibility and the performance levels of this new generation of ECR ion sources and required innovation on magnet construction, plasma chamber design, and beam transport. In this paper, the development, performance, and major innovations are described as well as a look to the potential to construct a fourth generation ECR ion source.

A tandem-based compact dual-energy gamma generator

A dual-energy tandem-type gamma generator has been developed at E. O. Lawrence Berkeley National Laboratory and Sandia National Laboratories. The tandem accelerator geometry allows higher energy nuclear reactions to be reached, thereby allowing more flexible generation of MeV-energy gammas for active interrogation applications. Both positively charged ions and atoms of hydrogen are created from negative ions via a gas stripper. In this paper, we show first results of the working tandem-based gamma generator and that a gas stripper can be utilized in a compact source design. Preliminary results of monoenergetic gamma production are shown.

Tissue reaction to implants of different metals: a study using guide wires in cannulated screws

Cannulated screws, along with guide wires, are typically used for surgical fracture treatment in cancellous bone. Breakage or bending deformation of the guide wire is a clinical concern. Mechanically superior guide wires made of Co-Cr alloys such as MP35N and L605 may reduce the occurrence of mechanical failures when used in combination with conventional (316L stainless steel) cannulated screws. However the possibility of galvanic or crevice corrosion and adverse tissue reaction, exists when using dissimilar materials, particularly in the event that a guide wire breaks, and remains in situ. Therefore, we designed an experiment to determine the tissue reaction to such an in vivo environment. Implant devices were designed to replicate a clinical situation where dissimilar metals can form a galvanic couple. Histological and SEM analyses were used to evaluate tissue response and corrosion of the implants. In this experiment, no adverse in vivo effects were detected from the use of dissimilar materials in a model of a broken guide wire in a cannulated screw.

Monitoring anticoagulation of primary haemostasis--estimation of platelet function in whole blood assays

This article provides an overview on current commercially available methods to determine primary haemostasis as a target of drug-mediated anticoagulation. It focuses on whole blood methods only, and references the currently major achievements that have been reported with each method in respect to its clinical use. Advantages and disadvantages of the various methods are presented, based on considerations of platelet physiology, and on feasibility of the procedures.

Drift compression of an intense neutralized ion beam

Longitudinal compression of a velocity-tailored, intense neutralized beam at 300 keV, 25 mA has been demonstrated. The compression takes place in a 1-2 m drift section filled with plasma to provide space-charge neutralization. An induction cell produces a head-to-tail velocity ramp that longitudinally compresses the neutralized beam, enhancing the beam peak current by a factor of 50 and producing a pulse duration of about 3 ns. This measurement has been confirmed independently with two different diagnostic systems.

Sertindole for schizophrenia

BACKGROUND

Sertindole is an atypical antipsychotic, which is thought to give a lower incidence of extrapyramidal side effects at clinically effective doses than typical antipsychotic drugs. In December 1998, Lundbeck Ltd., the manufacturers of sertindole, voluntarily suspended the availability of the drug due to concerns about cardiac arrhythmia and sudden cardiac death associated with its use. However, based on the advice of an appointed expert group, the Committee for Proprietary Medicinal Products (CPMP) lifted the suspension of sertindole in October 2001, a decision that was ratified by the European Commission on the 26th of June 2002. Lundbeck have committed to the CPMP to carry out two post-marketing surveillance (PMS) studies (which were initiated in July 2002) to provide additional epidemiological data under conditions of normal drug usage. Initial marketing of the product will be restricted and Lundbeck is currently in discussions with the US health authorities (FDA) to investigate whether, and if so when, it would be possible to launch Serdolect in the US market.

OBJECTIVES

To determine the effects of sertindole compared with placebo, typical and other atypical antipsychotic drugs for schizophrenia and related psychoses.

SEARCH STRATEGY

Our Initial searches included electronic searches of Biological Abstracts (1980-1999), The Cochrane Library (Issue 1, 1999), The Cochrane Schizophrenia Group's Register (August 2000), EMBASE (1980-1999), LILACS (1982-1996), MEDLINE (1966-1999), PSYNDEX (1977-1995) and PsycLIT (1974-1999). In addition, we searched pharmaceutical databases on the Dialog Corporation Datastar and Dialog services. We searched references of all identified studies for further trials. We contacted the manufacturer of sertindole and authors of trials. We updated the literature search by searching the Cochrane Schizophrenia Group's Trials Register in April 2003.

SELECTION CRITERIA

All randomised controlled trials that compared sertindole to placebo or other antipsychotic (atypical or typical) drug treatments for patients with schizophrenia or related psychosis .

DATA COLLECTION AND ANALYSIS

We independently inspected citations and, where possible abstracts; ordered papers for re-inspection and quality assessment and independently extracted data. For homogeneous dichotomous data, we calculated the risk ratio (RR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) or number needed to harm (NNH) on an intention-to-treat basis. For continuous data, we calculated weighted mean differences (WMD). We inspected all data for heterogeneity.

MAIN RESULTS

Currently the review includes three studies with a total of 1,104 participants. One was a medium term (eight weeks) placebo controlled study that examined three different doses of sertindole (8, 12 and 20mg/day). The remaining two studies compared the use of sertindole with haloperidol (10mg/day). One was a short term study (six weeks) that looked at four different doses of sertindole (8, 16, 20, 24mg/day) and the other was a long term study (one year) that evaluated the use of sertindole 24mg/day in participants attending outpatients. We excluded two large important studies because they did not report any usable data. (Both had greater than 50% loss to follow-up and data on 'leaving the study early' was inadequately reported). SERTINDOLE VERSUS PLACEBO: Sertindole at 20mg/day was found to be more effective than placebo in terms of BPRS total scores (1 study, n=78, MD 6.2, CI -11.8 to -0.6) and CGI total end point scores (1 study, n=78, MD -0.9, CI -1.6 to -0.2). A marginally statistically significantly greater number of participants that were treated with 20 mg of sertindole were reported to have been 'very much improved' as compared to those taking placebo (1 study, n=102, RR 7.6, CI 1.0 to 57.9, NNT 7.9, CI 4.3 to 41.1). There was no statistically significant difference between sertindole at 8 or 12 mg/day and placebo for these three outcome measures. There were no statistically significant differences between sertindole (8, 12 or 20 mg) and placebo for the incidence of extrapyramidal symptoms, extrapyramidal related events or use of medication to avoid extrapyramidal symptoms. There were no statistically significant differences found between sertindole and placebo for the movement disorders akathisia, cogwheel rigidity, hypertonia and tremor or somnolence. At eight weeks a statistically significant difference between placebo and all sertindole groups (8, 12 and 20 mg) for mean change from baseline in the QT and QTc intervals were observed (p values and SD were not reported). There was a statistically significant greater mean weight gain among participants taking sertindole (20 mg, mean weight gain of 3.3 kg) as compared to placebo (mean weight gain of 0.8 kg; p<0.05). SERTINDOLE VERSUS HALOPERIDOL: At one year, a greater number of participants who were treated with haloperidol as compared to sertindole (24mg/day) were leaving the study early due to any reason (1 study, n=282, RR 0.6, CI 0.4 to 1.0, NNH 8.8, CI 4.7 to 74.0) or non-compliance (1 study, n=282, RR 0.2, CI 0.0 to 0.7, NNH 12.8, CI 7.7 to 37.8). However, at six weeks, there was no statistically significant difference between sertindole (at 8, 16, 20, or 24mg) and haloperidol for this latter outcome. The incidence of EPS was higher among those treated with haloperidol than sertindole at 8, 16, 20 or 24mg/day (8mg: 1 study, n=245, RR 0.1, CI 0.0 to 0.7, NNH 11.4, CI 7.1 to 29.8; 16mg: 1 study, n=252, RR 0.3, CI 0.1 to 1.0, NNH 15.5, CI 8.0 to 217.9; and 20mg: 1 study, n=253, RR 0.2, CI 0.1 to 0.8, NNH 13.7, CI 7.7 to 68.3; 24mg: 2 studies, n=524, RR 0.6, CI 0.4 to 0.8, NNH 8.7, CI 5.4 to 23.0). More participants treated with haloperidol experienced akathisia, tremor and hypertonia than those treated with sertindole (Akathisia - 8mg: 1 study, n=245, RR 0.2, CI 0.1 to 0.5, NNH 6.0, CI 4.1 to 11.2; 16mg: 1 study, n=252, RR 0.1, CI 0.0 to 0.3, NNH 5.4, CI 3.9 9.0; 20mg: 1 study, n=253, RR 0.3, CI 0.2 to 0.7, NNH 7.3, CI 4.6 to 17.9; 24mg: 2 studies, n=524, RR 0.5, CI 0.3 to 0.7, NNH 8.6, CI 5.6 to 18.3. Tremor - 8mg: 1 study, n=245, RR 0.3, CI 0.1 to 0.7, NNH 8.5, CI 5.2 to 24.0; 16mg: 1 study, n=252, RR 0.2, CI 0.1 to 0.5, NNH 7.3, 4.8 to 15.6; 20mg: 1 study, n=253, RR 0.2, CI 0.1 to 0.6, NNH 7.8, CI 4.9 to 18.1; 24mg: 2 studies, n=524, RR 0.4, CI 0.2 to 0.6, NNH 8.2, CI 5.6 to 15.3. For Hypertonic - 24mg: 2 studies, n=524, RR 0.5, CI 0.3 to 0.8, NNH 12.4, CI 7.5 to 35.0; for sertindole 8, 16 and 20mg there was no statistically significant differences between the treatment groups). One study reported that at six weeks, there was a statistically significant greater increase from baseline to final value in mean QTc interval in the sertindole 16, 20 and 24mg groups (20, 26, and 24msec, respectively) than in the haloperidol group (0msec; p value was not reported), but no SD or any other measure of variance for the effect sizes were reported. For one long term study only one participant from the sertindole group (24mg) had a QT interval that exceeded 500msec (1 study, n=282, RR 3.0 CI 0.1 to 73.0), but 11participants treated with Sertindole had QTc intervals of at least 500msec, compared to none in the haloperidol treated group (1 study, n=282, RR 23.0, CI 1.4 to 386.6, NNH 12.8, CI 8.2 to 29.6). At six weeks, fewer participants treated with sertindole at 8mg or 24mg were affected by somnolence than those treated with haloperidol (sertindole 8mg: 1 study, n=245, RR 0.1, CI 0.0 to 0.7, NNH 11.4, CI 7.1 to 29.8; 24mg: 2 studies, n=524, RR 0.6, CI 0.4 to 1.0, NNH 14.8, CI 7.7 to 205.2). The incidence of rhinitis was found to be statistically significantly higher among those taking sertindole at 16 or 24mg as compared to haloperidol (16mg: 1 study, n=252, RR 10.8, CI 1.4 to 82.6, NNH 12.7, CI 7.7 to 36.7; 24mg: 2 studies, n= 524, RR 2.1, CI 1.4 to 3.1, NNH 8.7, CI 5.6 to 18.6). At one year, 33 participants treated with sertindole (24mg) had experienced the sexual adverse event of decreased ejaculatory volume, compared with six participants treated with haloperidol. However the number of included male participants was not reported and therefore the RR could not be calculated. At one year, more participants taking sertindole (24mg/day) had put on weight compared to those taking haloperidol (1 study, n=282, RR 6.3, CI 1.9 to 20.9, NNH 8.8, CI 5.7 to 19.1). At six weeks, all of the sertindole groups showed an increase in body weight from baseline to final evaluation ranging from 1.3kg to 1.9kg, all of which represented a statistically significantly different weight change than that recorded for the haloperidol treatment group (-0.1Kg). However, the actual weight gain for each sertindole dosage group was not reported and no SD or any other measure of variance was given.

AUTHORS' CONCLUSIONS

Sertindole at a dose of 20mg/day was found to be more antipsychotic than placebo. When used at 8, 12 or 20mg/day it appears to be as acceptable as placebo (in terms of various adverse events including movement disorders and somnolence), but seems to be associated with more cardiac problems (8, 12 or 20mg/day) and an increase in weight gain (20mg/day) than placebo. Sertindole at a dose of 24mg/day was better tolerated than haloperidol (in terms of participants leaving the study early). It was also found to be was associated with fewer movement disorders (at 8, 16, 20 or 24mg/day) and sedation (8 or 24mg/day) than haloperidol. However, it was shown to cause more cardiac anomalies (16, 20 or 24mg/day), weight gain (all doses combined), rhinitis (16 or 24mg/day), and problems with sexual functioning (24mg/day) than haloperidol. One short term study reported that sertindole 16mg/day was the most optimal dose.

Psychosocial assessment of patients who attend an accident and emergency department with self-harm

It has been recommended that all patients attending hospital accident and emergency departments in the United Kingdom (UK) with self-harm should be offered adequate psychosocial assessment to identify those at risk of completed suicide or repeated self-harm. This paper focuses on the extent to which this recommendation has been implemented in a large district general hospital in Wales, and compares the characteristics and hospital management of patients who received no specialist assessment with those who were assessed by a psychiatric liaison nurse or a psychiatrist. Data were routinely collected as part of the hospital annual audit procedure and confirm previous findings that guidelines for the general hospital management of self-harm patients have not been well implemented. Whilst we found some evidence that certain high risk patient groups were more likely to receive specialist assessment, this was far from universal. We conclude that if there is to be a reduction in the rate of suicide in Wales and the UK as a whole, it is crucial that services for people who self-harm are more appropriately targeted on patients who are at greatest risk.

Short shrift for the sane? The hospital management of self-harm patients with and without mental illness

In recent years the British government has sought to target service provision both on people with severe enduring mental illness and on those considered to be at risk of suicide. The study reported here suggests these policies may have had unforeseen repercussions on services for people who self-harm but have no identifiable mental illness. This paper compares the hospital management of self-harm patients with and without mental illness. Over the years 1996-2000, a total of 4,329 self-harm patient attendances were recorded at the accident and emergency department of a British hospital. Whilst patients in 63.7% of attendances could reasonably have been considered to have some form of mental illness, we found that in the remaining 36.3% of attendances (where patients had no indicator of mental illness) a particularly poor standard of service was given. We suggest that if government targets for a reduction in the suicide rate are to be met, it is crucial that there should be marked improvements in services for all self-harm patients presenting at accident and emergency departments. However, in improving services we must be vigilant to the danger that targeting those with a mental illness may mean we fail to provide even basic levels of care for others.

Morphological changes of the endometrial epithelium in the bitch during metoestrus and anoestrus

Although cyclic changes of the endometrium in dogs involving both stromal and glandular compartments have been described, the fate of the surface epithelium after progressive growth and secretion is still unclear. In the present study, uteri of 43 healthy bitches in metoestrus and anoestrus were examined macroscopically and histologically. Tissue biopsies were taken from three different locations (cranial and middle parts of uterine horns and bifurcation). The stage of the oestrous cycle was determined by evaluation of progesterone and oestradiol levels in plasma hormone and was also confirmed clinically. Crypts formed in the luteal phase were covered with a columnar epithelium which gradually underwent fatty degeneration. In addition, the stromal part of the crypts disappeared and finally, in early anoestrus, epithelial sheaths desquamated and shed off into the uterine lumen. The surface epithelium was replaced by new cuboidal cells proliferating and migrating from the glandular openings. These findings were confirmed by oil red O staining and immunohistochemical detection of proliferation with Ki-67 marker.

Lectin binding patterns in normal canine endometrium and in bitches with pyometra and cystic endometrial hyperplasia

Cystic endometrial hyperplasia (CEH) and pyometra in the bitch are dioestral syndromes, supposed to be caused by hormonal disturbances and changes in endometrial steroid hormone receptor levels. Histologically, the endometria show cystic dilated glands and, if bacteria succeed in invading the uterus, pyometra may develop in the following metoestrus. In this study, lectin histochemistry was performed on paraffin sections to compare carbohydrate expression of uterine glands and surface epithelium in healthy dogs and in dogs with CEH and pyometra. Lectin binding is a useful tool to identify glycoconjugates, especially of the glycocalyx, which has essential functions in the endometrium during reproduction. Uterine tissue was obtained from 18 healthy bitches in metoestrus or anoestrus and 18 bitches with a clinical diagnosis of CEH or pyometra. Normal endometria showed cycle-dependent changes in SBA, PNA, HPA and UEA binding during metoestrus and anoestrus. LCA did not show cycle-dependent changes and WGA bound to Golgi regions in the apical parts of surface epithelial cells only in metoestrous. Endometria with inflammatory alterations lost cycle-specific lectin binding patterns and, with increasing severity of pathological changes, showed a marked decrease in binding intensity to the glandular and surface epithelial glycocalyx and secretions. In dogs with CEH, unaltered glands with generally strong lectin binding to the glycocoalyx and Golgi regions were found adjacent to altered glands. The decrease of lectin binding in pyometra cases is supposed to be a result of glandular exhaustion after cystic hyperplasia. In addition, bacterial adhesion to sugar residues on the uterine surface epithelium might impede lectin binding.

Combined phase locking and beam shaping of a multicore fiber laser by structured mirrors

We present a novel mirror geometry combining the two features of phase locking and simultaneous beam shaping of the emission of a multicore fiber (MCF) laser. In the experiments we applied a Talbot cavity to a diode-pumped MCF laser with 18 microcores placed on a ring. The feedback mirror consisted of a highly reflecting structure with 18 spokes and a circle in the center deposited on a glass substrate. The spokes increased the discrimination between the supermodes and suppressed independent lasing of the individual emitters. The central dot caused strong diffraction of the output radiation, leading to a shaped beam profile. The output power of the phase-locked MCF laser exceeded 5 W.

Phase locking in a multicore fiber laser by means of a Talbot resonator

We report phase locking of a diode-pumped multicore fiber laser with a circular array of 18 Nd-doped emitters (microcores) acting as an active medium. Phase locking was achieved in a Talbot resonator configuration. We present calculations of the effective reflection coefficients that are due to self-imaging. Far-field distributions and near-field pattern of several supermodes are calculated and compared with experimental results.

Attenuated nontoxinogenic and nonencapsulated recombinant Bacillus anthracis spore vaccines protect against anthrax

Several highly attenuated spore-forming nontoxinogenic and nonencapsulated Bacillus anthracis vaccines differing in levels of expression of recombinant protective antigen (rPA) were constructed. Biochemical analyses (including electrospray mass spectroscopy and N terminus amino acid sequencing) as well as biological and immunological tests demonstrated that the rPA retains the characteristics of native PA. A single immunization of guinea pigs with 5 x 10(7) spores of one of these recombinant strains, MASC-10, expressing high levels of rPA (>/=100 microgram/ml) from a constitutive heterologous promoter induced high titers of neutralizing anti-PA antibodies. This immune response was long lasting (at least 12 months) and provided protection against a lethal challenge of virulent (Vollum) anthrax spores. The recombinant B. anthracis spore vaccine appears to be more efficacious than the vegetative cell vaccine. Furthermore, while results clearly suggest a direct correlation between the level of expression of PA and the potency of the vaccine, they also suggest that some B. anthracis spore-associated antigen(s) may contribute in a significant manner to protective immunity.

Loxapine for schizophrenia

BACKGROUND

Loxapine is a drug with D2/D3 receptor antagonist activity and a higher affinity for D3 than D2. Some authors have suggested that loxapine is more effective than typical antipsychotics in reducing the negative symptoms of schizophrenia, that extrapyramidal side-effects are not usually seen at clinically effective antipsychotic doses and that it should therefore be classed as atypical.

OBJECTIVES

To determine the effects of loxapine compared with placebo, typical and other atypical antipsychotic drugs for schizophrenia and related psychoses.

SEARCH STRATEGY

Electronic searches of Biological Abstracts (1980-1999), The Cochrane Library (Issue 1, 1999), The Cochrane Schizophrenia Group's Register (January 1999), EMBASE (1980-1999), MEDLINE (1966-1999), LILACS (1982-1996), PSYNDEX (1977-1995) and PsycLIT (1974-1999) were undertaken. In addition, pharmaceutical databases on the Dialog Corporation Datastar and Dialog services were searched. References of all identified studies were searched for further trials. Pharmaceutical companies and authors of trials were contacted.

SELECTION CRITERIA

All randomised controlled clinical trials relevant to the care of schizophrenia that compared loxapine to other treatments.

DATA COLLECTION AND ANALYSIS

Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were independently extracted but excluded if loss to follow up was greater than 50%. For homogeneous dichotomous data the risk ratio (RR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) were calculated on an intention-to-treat basis. For continuous data, weighted mean differences were calculated (WMD). All data were inspected for heterogeneity.

MAIN RESULTS

Compared to placebo, loxapine is antipsychotic (Global effect - not improved at 6 weeks, n=66, RR 0.6 CI 0.4-0.9 NNT 4 CI 2-62) with similar adverse effect profile to typical drugs. Is as effective as typical drugs in the short term (4-12 weeks) (Global effect - not improved, n=411, RR 0.89 CI 0.7-1.2). Very limited heterogeneous data suggest that, given intramuscularly (IM), loxapine may be at least as sedating as IM haloperidol and thiothixene.

REVIEWER'S CONCLUSIONS

Loxapine is antipsychotic but its effects are under researched. It is not clearly different from typical drugs in either its positive or adverse effects.

Sertindole for schizophrenia

BACKGROUND

Sertindole is an atypical antipsychotic, which is thought to give a lower incidence of extrapyramidal side effects at clinically effective doses than typical antipsychotic drugs. In December 1998, Lundbeck Ltd., the manufacturers of sertindole, voluntarily suspended the availability of the drug due to concerns about cardiac arrhythmia and sudden cardiac death associated with its use. Sertindole has therefore been withdrawn from the market pending discussion with the European Regulatory Authority over cardiac safety.

OBJECTIVES

To determine the effects of sertindole compared with placebo, typical and other atypical antipsychotic drugs for schizophrenia and related psychoses.

SEARCH STRATEGY

Electronic searches of Biological Abstracts (1980-1999), The Cochrane Library (Issue 1, 1999), The Cochrane Schizophrenia Group's Register (January 1999), EMBASE (1980-1999), LILACS (1982-1996), MEDLINE (1966-1999), PSYNDEX (1977-1995) and PsycLIT (1974-1999) were undertaken. In addition, pharmaceutical databases on the Dialog Corporation Datastar and Dialog services were searched. References of all identified studies were searched for further trials. The manufacturer of sertindole and authors of trials were contacted.

SELECTION CRITERIA

All randomised controlled trials that compared sertindole to placebo or other antipsychotic drug treatments were included by independent assessment.

DATA COLLECTION AND ANALYSIS

Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were independently extracted. For homogeneous dichotomous data the risk ratio (RR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) or numbers needed to harm (NNH) were calculated on an intention-to-treat basis. For continuous data, weighted mean differences (WMD) were calculated. All data were inspected for heterogeneity.

MAIN RESULTS

Two large important studies were excluded, because they did not report any usable data. The two that were included suggested that sertindole was more antipsychotic than placebo, as acceptable as placebo and better tolerated than haloperidol (NNT=9, RR 0.63 CI 0.41 to 0.96). Sertindole was associated with fewer movement disorders than haloperidol but was shown to cause more weight gain (NNH=9 RR 6.33, CI 1.92 to 20.92), rhinitis (NNH=8, RR 1.74, CI 1,28 to 2.36) and possibly male sexual dysfunction. Cardiac problems (QTc intervals of at least 500msec) were evident even in the randomised trials (NNH=13 RR 23, CI 1.37 to 386.60).

REVIEWER'S CONCLUSIONS

Because of the cardiac problems, even evident within poorly reported studies, at present sertindole should, if possible, be avoided. If sertindole is to be reintroduced, gold-standard evidence of its clinical benefits will need to far outweigh its real risks.

Zotepine for schizophrenia

BACKGROUND

Typical antipsychotic drugs are widely used as first line treatment for people with schizophrenia. The atypical class of antipsychotic drugs, however, is making important inroads into this approach and zotepine is one such compound. It is a dopamine antagonist and claimed to be to be particularly effective for negative symptoms

OBJECTIVES

To determine the effects of zotepine compared with placebo, typical and other atypical antipsychotic drugs for schizophrenia and related psychoses.

SEARCH STRATEGY

Electronic searches of Biological Abstracts (1980-1999), CINAHL (1982-1999), The Cochrane Library (Issue 1, 1999), The Cochrane Schizophrenia Group's Register (January 1999), EMBASE (1980-1999), Dialog Corporation Datastar service (1999), MEDLINE (1966-1999), and PsycLIT (1974-1999) were undertaken. References of all identified studies were searched for further trials. Knoll Pharmaceuticals and authors of trials were contacted.

SELECTION CRITERIA

All randomised clinical trials that compared zotepine to other treatments for people with schizophrenia or other psychoses were included.

DATA COLLECTION AND ANALYSIS

Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were independently extracted. Data were excluded if loss to follow up was greater than 50%. For homogeneous dichotomous data the relative risk (RR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) and numbers needed to harm (NNH), were calculated on an intention-to-treat basis. For continuous data, weighted mean differences were calculated (WMD). All data were inspected for heterogeneity.

MAIN RESULTS

All outcomes were short term (4-12 weeks). Limited data suggest that zotepine is an antipsychotic, at least as effective as typical drugs. Mental state measures of 'no clinically important improvement' favour zotepine when compared to other active drugs (n=356, RR 0.8 CI 0.7-0.9, NNT 7 CI 4-22). About one third of people in both zotepine and control groups left the studies before trial completion. Zotepine may result in less movement disorder adverse effects than typical antipsychotic drugs. Trials have not highlighted clear differences between zotepine and other atypical drugs.

REVIEWER'S CONCLUSIONS

Zotepine may be a valuable addition to the increasing ranks of atypical antipsychotic drugs. More data from already existing studies is urgently needed to increase the confidence in the findings of this review. New data from well planned, conducted and reported long term pragmatic randomised trials are necessary. Otherwise clinical use of zotepine will be based on speculation on the meaning of the findings of short explanatory trials for everyday practice.

Self-starting mode locking of a Nd:glass fiber laser by use of the third-order nonlinearity of low-temperature-grown GaAs

We present a diode-pumped Nd:glass fiber laser, emitting at 1060 nm, that is passively mode locked by fast nonlinear loss in low-temperature-grown GaAs (LT-GaAs). This new mode-locking mechanism is based on intensity-dependent defocusing in LT-GaAs that occurs after nonresonant generation of free carriers by two-photon absorption. Mode locking is self-starting and produces pulses as short as 4.1 ps.

Diode-pumped 1-W Er-doped fluoride glass M-profile fiber laser emitting at 2.8 mum

We report a novel short-length diode-pumped cw fiber laser with high output power at a wavelength of 2.8mum . The system combines continuous-wave diode pumping at 970 nm, a high doping concentration (5-mol. % ErF(3)) of the active fiber, and an annular geometry of the laser medium, an M-profile fiber. Output powers in excess of 1 W with a slope efficiency of 25% were obtained.

Structural modifications of the omega loop in human acetylcholinesterase

Conformational mobility of the surface omega loop (Cys-69-Cys-96) in human acetylcholinesterase (HuAChE) was recently implicated in substrate accessibility to the active center and in the mechanism of allosteric modulation of enzymatic activity. We therefore generated and kinetically evaluated the following modifications or replacements in HuAChE: (a) residues at the loop ends, (b) residues involved in putative hydrogen-bond interactions within the loop and between the loop and the protein core, (c) ChEs conserved proline residues within the loop and (d) a deletion of a conserved segment of 5 residues. All the residue replacements, including those of the prolines, had either limited or no effect on enzyme reactivity. These results suggest that unlike the case of lipase, the omega loop in the HuAChE is not involved in large lid-like displacements. In cases where modifications of the loop sequence had some effect on reactivity, the effects could be attributed to an altered position of residue Trp-86 supporting the proposed coupling between the structure of the omega loop and the positioning of the Trp-86 indole moiety, in catalytic activity and in allosterism.

N-glycosylation of human acetylcholinesterase: effects on activity, stability and biosynthesis

The role of N-glycosylation in the function of human acetylcholinesterase (HuAChE) was examined by site-directed mutagenesis (Asn to Gln substitution) of the three potential N-glycosylation sites Asn-265, Asn-350 and Asn-464. Analysis of HuAChE mutants, defective in a single or multiple N-glycosylation sites, by expression in transiently or stably transfected human embryonal 293 kidney cells suggests the following. (a) All three AChE glycosylation signals are utilized, but not all the secreted molecules are fully glycosylated. (b) Glycosylation at all sites is important for effective biosynthesis and secretion; extracellular AChE levels in mutants defective in one, two or all three sites amounted to 20-30%, 2-4% and about 0.5% of wild-type level respectively. (c) Some glycosylation mutants display impaired stability, as reflected by increased susceptibility to heat inactivation; substitution of Asn-464 has the most pronounced effect on thermostability. (d) Abrogation of N-glycosylation has no detectable effect on the enzyme activity of HuAChE; all glycosylation mutants, including the triple mutant, hydrolyse acetylthiocholine efficiently, displaying Km, kcat. and kcat./Km values similar to those of the wild-type enzyme. (e) In most mutants, inhibition profiles with edrophonium and bisquaternary ammonium ligands are identical with those of wild-type enzyme; the Asn-350 mutants, however, exhibit a slight decrease in their affinity towards these ligands. (f) Elimination of oligosaccharide side chains has no detectable effect on the surface-related 'peripheral-site' functions; like the wild-type enzyme, all mutants were inhibited by propidium and by increased concentrations of acetylthiocholine.

Dissection of the human acetylcholinesterase active center determinants of substrate specificity. Identification of residues constituting the anionic site, the hydrophobic site, and the acyl pocket

Substrate specificity determinants of human acetylcholinesterase (HuAChE) were identified by combination of molecular modeling and kinetic studies with enzymes mutated in residues Trp-86, Trp-286, Phe-295, Phe-297, Tyr-337, and Phe-338. The substitution of Trp-86 by alanine resulted in a 660-fold decrease in affinity for acetythiocholine but had no effect on affinity for the isosteric uncharged substrate (3,3-dimethylbutylthioacetate). The results demonstrate that residue Trp-86 is the anionic site which binds, through cation-pi interactions, the quaternary ammonium of choline, and that of active center inhibitors such as edrophonium. The results also suggest that in the non-covalent complex, charged and uncharged substrates with a common acyl moiety (acetyl) bind to different molecular environments. The hydrophobic site for the alcoholic portion of the covalent adduct (tetrahedral intermediate) includes residues Trp-86, Tyr-337, and Phe-338, which operate through nonpolar and/or stacking interactions, depending on the substrate. Substrates containing choline but differing in the acyl moiety (acetyl, propyl, and butyryl) revealed that residues Phe-295 and Phe-297 determine substrate specificity of the acyl pocket for the covalent adducts. Phe-295 also determines substrate specificity in the non-covalent enzyme substrate complex and thus, the HuAChE F295A mutant exhibits over 130-fold increase in the apparent bimolecular rate constant for butyrylthiocholine compared with wild type enzyme. Reactivity toward specific butyrylcholinesterase inhibitors is similarly dependent on the nature of residues at positions 295 and 297. Amino acid Trp-286 at the rim of the active site "gorge" and Trp-86, in the active center, are essential elements in the mechanism of inhibition by propidium, a peripheral anionic site ligand. Molecular modeling and kinetic data suggest that a cross-talk between Trp-286 and Trp-86 can result in reorientation of Trp-86 which may then interfere with stabilization of substrate enzyme complexes. It is proposed that the conformational flexibility of aromatic residues generates a plasticity in the active center that contributes to the high efficiency of AChE and its ability to respond to external stimuli.

Production and secretion of high levels of recombinant human acetylcholinesterase in cultured cell lines: microheterogeneity of the catalytic subunit

To allow for structural analysis of the human acetylcholinesterase (hAChE) subunit, a series of eukaryotic vectors was designed for efficient expression. Several eukaryotic multicistronic expression vectors were tested in various mammalian cell lines. All expression vectors contained the selectable neo gene under control of a weak promoter, while the hAChE cDNA was under control of the cytomegalovirus (CMV) immediate-early or Rous sarcoma virus long terminal repeat (RSV LTR) or simian virus 40 (SV40) early promoters. Optimal production and secretion of recombinant hAChE (rehAChE) was achieved in the embryonal kidney 293 cell line transfected either with the RSV-hAChE or with CMV-hAChE expression vectors. Clones expressing and secreting as much as 5-25 pg of enzyme per cell per 24 h were obtained without resorting to coamplification techniques or continuous maintenance of cells under selective pressure. The purified (specific activity of 6000 units per mg protein) homodimer and tetramer enzyme molecules displayed typical AChE biochemical properties: a Km value of 120 microM for acetylthiocholine; a kcat value of 3.9 x 10(5)/min, and selective by AChE-specific inhibitors. Catalytic subunit dimers (130 kDa) exhibit differential N-glycosylation patterns, and upon reduction resolve into 67- and 70-kDa monomeric subunits. These two forms appear as a single discrete 62-kDa band following deglycosylation by N-glycanase. The N-terminal amino acid sequence analysis of the purified mature enzyme suggests the existence of two alternative cleavage sites for the removal of the signal peptide, in which the 'mature' position 1 is either Ala31 or Gly33. Both of these positions conform with the consensus signal peptide recognition sequences and demonstrate bidirected processing of signal peptides on a native molecule.

Substrate inhibition of acetylcholinesterase: residues affecting signal transduction from the surface to the catalytic center

Amino acids located within and around the 'active site gorge' of human acetylcholinesterase (AChE) were substituted. Replacement of W86 yielded inactive enzyme molecules, consistent with its proposed involvement in binding of the choline moiety in the active center. A decrease in affinity to propidium and a concomitant loss of substrate inhibition was observed in D74G, D74N, D74K and W286A mutants, supporting the idea that the site for substrate inhibition and the peripheral anionic site overlap. Mutations of amino acids neighboring the active center (E202, Y337 and F338) resulted in a decrease in the catalytic and the apparent bimolecular rate constants. A decrease in affinity to edrophonium was observed in D74, E202, Y337 and to a lesser extent in F338 and Y341 mutants. E202, Y337 and Y341 mutants were not inhibited efficiently by high substrate concentrations. We propose that binding of acetylcholine, on the surface of AChE, may trigger sequence of conformational changes extending from the peripheral anionic site through W286 to D74, at the entrance of the 'gorge', and down to the catalytic center (through Y341 to F338 and Y337). These changes, especially in Y337, could block the entrance/exit of the catalytic center and reduce the catalytic efficiency of AChE.

Mutagenesis of human acetylcholinesterase. Identification of residues involved in catalytic activity and in polypeptide folding

Evidence for the involvement of Ser-203, His-447, and Glu-334 in the catalytic triad of human acetylcholinesterase was provided by substitution of these amino acids by alanine residues. Of 20 amino acid positions mutated so far in human acetylcholinesterase (AChE), these three were unique in abolishing detectable enzymatic activity (less than 0.0003 of wild type), yet allowing proper production, folding, and secretion. This is the first biochemical evidence for the involvement of a glutamate in a hydrolase triad (Schrag, J.D., Li, Y., Wu, M., and Cygler, M. (1991) Nature 351, 761-764), supporting the x-ray crystal structure data of the Torpedo californica acetylcholinesterase (Sussman, J.L., Harel, M., Frolow, F., Oefner, C., Goldman, A., Toker, L. and Silman, I. (1991) Science 253, 872-879). Attempts to convert the AChE triad into a Cys-His-Glu or Ser-His-Asp configuration by site-directed mutagenesis did not yield effective AChE activity. Another type of substitution, that of Asp-74 by Gly or Asn, generated an active enzyme with increased resistance to succinylcholine and dibucaine; thus mimicking in an AChE molecule the phenotype of the atypical butyrylcholinesterase natural variant (D70G mutation). Mutations of other carboxylic residues Glu-84, Asp-95, Asp-333, and Asp-349, all conserved among cholinesterases, did not result in detectable alteration in the recombinant AChE, although polypeptide productivity of the D95N mutant was considerably lower. In contrast, complete absence of secreted human AChE polypeptide was observed when Asp-175 or Asp-404 were substituted by Asn. These two aspartates are conserved in the entire cholinesterase/thyroglobulin family and appear to play a role in generating and/or maintaining the folded state of the polypeptide. The x-ray structure of the Torpedo acetylcholinesterase supports this assumption by revealing the participation of these residues in salt bridges between neighboring secondary structure elements.