Characteristics of clinical-pharmacological recommendations in psychiatry in Germany

OBJECTIVE

Psychiatric patients in general, and elderly psychiatric patients in particular, are at risk of adverse drug reactions due to comorbidities and inappropriate polypharmacy. Interdisciplinary and clinical-pharmacologist-led medication reviews may contribute to medication safety in the field of psychiatry. In this study, we reported the frequency and characteristics of clinical-pharmacological recommendations in psychiatry, with a particular focus on geriatric psychiatry.

METHOD

A clinical pharmacologist, in collaboration with the attending psychiatrists and a consulting neurologist, conducted interdisciplinary medication reviews in a general psychiatric ward with a geropsychiatric focus at a university hospital over a 25-week period. All clinical and pharmacological recommendations were recorded and evaluated.

RESULTS

A total of 316 recommendations were made during 374 medication reviews. Indications/contraindications of drugs were the most frequently discussed topics (59/316; 18.7 %), followed by dose reductions (37/316; 11.7 %), and temporary or permanent discontinuation of medications (36/316; 11.4 %). The most frequent recommendations for dose reduction involvedbenzodiazepines (9/37; 24.3 %). An unclear or absent indication was the most common reason for recommending temporary or permanent discontinuation of the medication (6/36; 16.7 %).

CONCLUSION

Interdisciplinary clinical pharmacologist-led medication reviews represented a valuable contribution to medication management in psychiatric patients, particularly the elderly ones.

Drug safety in older patients with alcohol use disorder: a retrospective cohort study

Background

Older patients with alcohol use disorder are at particular risk of developing adverse drug reactions due to multimorbidity, polypharmacy, and altered organ function.

Objectives

In this study, we investigated the frequency and characteristics of potentially serious alcohol-medication interactions, potentially inappropriate medications (PIMs) for older adults, and potential drug-drug interactions (pDDIs) in a population of older patients with alcohol use disorder over a 10-year period.

Design

Retrospective monocentric cohort study.

Methods

Prescribed medications were screened for potentially serious alcohol-medication interactions, PIMs, and pDDIs using the POSAMINO (POtentially Serious Alcohol-Medication INteractions in Older adults) criteria, the PRISCUS 2.0 list, the FORTA (Fit fOR The Aged) classification, and the drug interaction program AiDKlinik®.

Results

We enrolled 114 patients aged ⩾65 years with alcohol use disorder, who were treated in an addiction unit of a university hospital in Germany. About 80.7% of the study population had at least one potentially serious alcohol-medication interaction. Potentially serious alcohol-medication interactions most commonly affected the cardiovascular (57.7%) and the central nervous system (32.3%). A total of 71.1% of the study population received at least one prescription of a FORTA C or D drug, compared with 42.1% who received at least one PIM prescription according to the PRISCUS 2.0 list. A total of 113 moderate and 72 severe pDDIs were identified in the study population.

Conclusion

Older patients with alcohol use disorders are frequently exposed to potentially serious alcohol-medication interactions, PIMs, and pDDIs. Improvements in the quality of prescribing should primarily target the use of cardiovascular and psychotropic drugs.

Potentially inappropriate prescriptions of antibiotics in geriatric psychiatry-a retrospective cohort study

Introduction

Older patients are frequently affected by infectious diseases and adverse drug reactions (ADRs) of consecutively prescribed antibiotics. Particularly within geriatric psychiatry, high rates of potentially inappropriate prescriptions (PIPs) have been described, significantly complicating pharmacological treatment. Therefore, this study aimed to investigate the frequency and characteristics of antibiotic PIPs in geriatric psychiatry.

Methods

Medication charts of 139 patient cases (mean age 78.8 years; 69.8% female) receiving antibiotic treatment on a geriatric psychiatric ward were analyzed. Utilizing previously published definitions of antibiotic PIPs, adequacy of the antibiotic prescriptions was subsequently assessed.

Results

16.3% of all screened patient cases (139/851) received an antibiotic treatment during their inpatient stay. 59.5% of antibiotic prescriptions were due to urinary tract infections, followed by pulmonary (13.3%) and skin and soft tissue infections (11.3%). 46.7% of all antibiotic prescriptions fulfilled at least one PIP criterium, with the prescription of an antibiotic course for more than seven days as the most common PIP (15.3%).

Discussion

Antibiotic PIPs can be considered as a frequent phenomenon in geriatric psychiatry. Especially the use of fluoroquinolones and cephalosporins should be discussed critically due to their extensive side effect profiles. Due to the special characteristics of geriatric psychiatric patients, international guidelines on the use of antibiotics should consider frailty and psychotropic polypharmacy of this patient population more closely.

Preinterventional Third-Molar Assessment Using Robust Machine Learning

Machine learning (ML) models, especially deep neural networks, are increasingly being used for the analysis of medical images and as a supporting tool for clinical decision-making. In this study, we propose an artificial intelligence system to facilitate dental decision-making for the removal of mandibular third molars (M3M) based on 2-dimensional orthopantograms and the risk assessment of such a procedure. A total of 4,516 panoramic radiographic images collected at the Center of Dental Medicine at the University of Zurich, Switzerland, were used for training the ML model. After image preparation and preprocessing, a spatially dependent U-Net was employed to detect and retrieve the region of the M3M and inferior alveolar nerve (IAN). Image patches identified to contain a M3M were automatically processed by a deep neural network for the classification of M3M superimposition over the IAN (task 1) and M3M root development (task 2). A control evaluation set of 120 images, collected from a different data source than the training data and labeled by 5 dental practitioners, was leveraged to reliably evaluate model performance. By 10-fold cross-validation, we achieved accuracy values of 0.94 and 0.93 for the M3M-IAN superimposition task and the M3M root development task, respectively, and accuracies of 0.9 and 0.87 when evaluated on the control data set, using a ResNet-101 trained in a semisupervised fashion. Matthew's correlation coefficient values of 0.82 and 0.75 for task 1 and task 2, evaluated on the control data set, indicate robust generalization of our model. Depending on the different label combinations of task 1 and task 2, we propose a diagnostic table that suggests whether additional imaging via 3-dimensional cone beam tomography is advisable. Ultimately, computer-aided decision-making tools benefit clinical practice by enabling efficient and risk-reduced decision-making and by supporting less experienced practitioners before the surgical removal of the M3M.

Controlling cleaning agent residues in pharmaceutical manufacturing: A harmonized scientific strategy

This paper proposes a scientifically justified and harmonized strategy to control cleaning agent ingredients' (CAIs) residues in pharmaceutical manufacturing. Firstly, we demonstrate that worst-case cleaning validation calculations on CAI residuals with representative GMP standard cleaning limits (SCLs) are enough to control CAI residues of low concern to safe levels. Secondly, a new harmonized strategy for the toxicological assessment of CAI residuals is presented and validated. The results establish a framework applicable to cleaning agent mixtures based on hazard and exposure considerations. This framework is primarily based on the hierarchy of a single CAI's critical effect, where the lowest resulting limit may become the driver of the cleaning validation process. The six critical effect groups are: (1) CAIs of low concern based on safe exposure reasoning; (2) CAIs of low concern based on the mode of action reasoning; (3) CAIs with local concentration-dependent critical effects; (4) CAIs with dose-dependent systemic critical effects for which a route-specific PDE should be calculated; (5) poorly characterized CAIs with unknown critical effect for which a default value of 100 μg/day is proposed; (6) poorly characterized CAIs which should be avoided because of potential mutagenicity and/or potency.

Determinants of severe QTc prolongation in a real-world gerontopsychiatric setting

Introduction

QT_c prolongation carries the risk of ventricular tachyarrhythmia (Torsades de Pointes) and sudden cardiac death. Psychotropic drugs can affect ventricular repolarization and thus prolong the QT_c interval. The present study sought to investigate the risk factors (pharmacological and non-pharmacological) of severe QT_c prolongation in gerontopsychiatric patients.

Methods

Electrocardiograms of patients on a gerontopsychiatric ward were screened for QT_c prolongation. Medication lists were examined utilizing the AzCERT classification. Potential drug interactions were identified with the electronic drug interaction program mediQ.

Results

The overall prevalence of QT_c prolongation was 13.6%, with 1.9% displaying severe QT_c prolongation (≥ 500 ms). No statistically significant differences between patients with moderate and severe QT_c prolongation were identified; however, patients with severe QT_c prolongation tended to take more drugs (p = 0.063). 92.7% of patients with QT_c prolongation took at least one AzCERT-listed drug, most frequently risperidone and pantoprazole. Risperidone and pantoprazole, along with pipamperone, were also most frequently involved in potential drug interactions. All patients displayed additional risk factors for QT_c prolongation, particularly cardiac diseases.

Conclusion

In addition to the use of potentially QT_c-prolonging drugs, other risk factors, especially cardiac diseases, appear to be relevant for the development of QT_c prolongation in gerontopsychiatric patients. Pantoprazole was frequently involved in potential drug interactions and should generally not be used for more than 8 weeks in geriatric populations. As clinical consequences of QT_c prolongation were rare, potentially QT_c-prolonging drugs should not be used overcautiously; their therapeutic benefit should be considered as well. It is paramount to perform diligent benefit-risk analyses prior to the initiation of potentially QT_c-prolonging drugs and to closely monitor their clinical (side) effects.

PDE concept for controlling cleaning agent residues in pharmaceuticals- A critical analysis

Cleaning agents (CAs) are used in multipurpose facilities to control carryover contamination of active pharmaceutical ingredients (APIs) to scientifically justified limits. While this is often done with the PDE methodology used for API impurities, it is unclear if it is justifiable and necessary for cleaning agents, which generally represent a comparatively lower health risk. Comparing calculated oral PDE values for CA ingredients (CAIs) from four companies with PDEs of a selected number of small-molecule APIs showed that the toxicity of CAIs is several orders of magnitude lower. Furthermore, a critical review of the toxicity and everyday exposure to the general population of the main CAIs functional groups showed that the expected health risks are generally negligible. This is particularly true if the associated mode of actions cause local toxicity that is usually irrelevant at the concentration of potential residue carryover. This work points towards alternative approaches to the PDE concept to control CAIs' contamination and provides some guidance on grouping and identifying compounds with lower health risks based on exposure and mode of action reasoning. In addition, this work supports the concept that limit values should only be set for CAIs of toxicological concern.

Vaginal-perineal cultures for detecting group B streptococci and extended spectrum β-lactamase producing bacteria in pregnancy

OBJECTIVE

To compare the detection rates of vaginal-perineal cultures for group B streptococci (GBS) with the standard vaginal and rectal cultures and evaluate the diagnostic yield of vaginal-perineal vs. rectal swabs for extended spectrum β-lactamase producing Enterobacterales (ESBL-E) during the third trimester of pregnancy.

STUDY DESIGN

Vagino-perineal and rectal swabs were collected cross-sectionally from pregnant women between 35-37 weeks gestation and tested for the presence of GBS and ESBL-E. Accuracy of the vagino-perineal swab was compared to the combined vagino-perineal/rectal swab. Risk factors for ESBL carriage were examined. Degrees of pain, discomfort and stress related to the rectal swab were analyzed on visual analogue scales.

RESULTS

48 out of 250 participants (19.2%) were GBS positive. The vagino-perineal swab was positive in 44 of 48 women (91.7%) yielding a negative predictive value of 98.1%. Agreement (kappa) between the two methods was 0.95. Six out of 190 women with additional ESBL-E screening (3.2%) tested positive by rectal swab. Of these, only two had also a positive vagino-perineal swab. The rectal swab caused overall little subjective discomfort, pain or stress, as indicated by low scores indicated on the visual scales.

CONCLUSIONS

The GBS detection rate of the vagino-perineal swab was lower compared to the reference standard. However, agreement between the two screening methods was high and there were no cases of GBS neonatal sepsis in the recruited population, supporting this less invasive screening strategy. In contrast, the vaginal-perineal swab was inferior to the rectal swab for detecting ESBL-E, indicating that this less invasive method for detecting antibiotic resistant bacteria that may be potentially transferred to the neonate during labor and delivery would be inappropriate for ESBL-E screening in pregnant women. The low ESBL-E carriage rate among pregnant women likely reflects the prevalence in the general population.

[Linkage to care after first hospitalisation for psychosis]

BACKGROUND

First hospitalisation for a psychotic episode causes intense distress to patients and families, but offers an opportunity to make a diagnosis and start treatment. However, linkage to outpatient psychiatric care remains a notoriously difficult step for young psychotic patients, who frequently interrupt treatment after hospitalisation. Persistence of symptoms, and untreated psychosis may therefore remain a problem despite hospitalisation and proper diagnosis. With persisting psychotic symptoms, numerous complications may arise: breakdown in relationships, loss of family and social support, loss of employment or study interruption, denial of disease, depression, suicide, substance abuse and violence. Understanding mechanisms that might promote linkage to outpatient psychiatric care is therefore a critical issue, especially in early intervention in psychotic disorders.

OBJECTIVE

To study which factors hinder or promote linkage of young psychotic patients to outpatient psychiatric care after a first hospitalisation, in the absence of a vertically integrated program for early psychosis. Method. File audit study of all patients aged 18 to 30 who were admitted for the first time to the psychiatric University Hospital of Lausanne in the year 2000. For statistical analysis, chi2 tests were used for categorical variables and t-test for dimensional variables; p<0.05 was considered as statistically significant.

RESULTS

230 patients aged 18 to 30 were admitted to the Lausanne University psychiatric hospital for the first time during the year 2000, 52 of them with a diagnosis of psychosis (23%). Patients with psychosis were mostly male (83%) when compared with non-psychosis patients (49%). Furthermore, they had (1) 10 days longer mean duration of stay (24 vs 14 days), (2) a higher rate of compulsory admissions (53% vs 22%) and (3) were more often hospitalised by a psychiatrist rather than by a general practitioner (83% vs 53%). Other socio-demographic and clinical features at admission were similar in the two groups. Among the 52 psychotic patients, 10 did not stay in the catchment area for subsequent treatment. Among the 42 psychotic patients who remained in the catchment area after discharge, 20 (48%) did not attend the scheduled or rescheduled outpatient appointment. None of the socio demographic characteristics were associated with attendance to outpatient appointments. On the other hand, voluntary admission and suicidal ideation before admission were significantly related to attending the initial appointment. Moreover, some elements of treatment seemed to be associated with higher likelihood to attend outpatient treatment: (1) provision of information to the patient regarding diagnosis, (2) discussion about the treatment plan between in- and outpatient staff, (3) involvement of outpatient team during hospitalisation, and (4) elaboration of concrete strategies to face basic needs, organise daily activities or education and reach for help in case of need.

CONCLUSION

As in other studies, half of the patients admitted for a first psychotic episode failed to link to outpatient psychiatric care. Our study suggests that treatment rather than patient's characteristics play a critical role in this phenomenon. Development of a partnership and involvement of patients in the decision process, provision of good information regarding the illness, clear definition of the treatment plan, development of concrete strategies to cope with the illness and its potential complications, and involvement of the outpatient treating team already during hospitalisation, all came out as critical strategies to facilitate adherence to outpatient care. While the current rate of disengagement after admission is highly concerning, our finding are encouraging since they constitute strategies that can easily be implemented. An open approach to psychosis, the development of partnership with patients and a better coordination between inpatient and outpatient teams should therefore be among the targets of early intervention programs. These observations might help setting up priorities when conceptualising new programs and facilitate the implementation of services that facilitate engagement of patients in treatment during the critical initial phase of psychotic disorders.

Laser Doppler distance sensor using phase evaluation

This paper presents a novel optical sensor which allows simultaneous measurements of axial position and tangential velocity of moving solid state objects. An extended laser Doppler velocimeter setup is used with two slightly tilted interference fringe systems. The distance to a solid state surface can be determined via a phase evaluation. The phase laser Doppler distance sensor offers a distance resolution of 150 nm and a total position uncertainty below 1 microm. Compared to conventional measurement techniques, such as triangulation, the distance resolution is independent of the lateral surface velocity. This advantage enables precise distance and shape measurements of fast rotating surfaces.

Renal tolerability of intermittent intravenous ibandronate treatment for patients with postmenopausal osteoporosis: a review

While intravenous (IV) bisphosphonates are well established in managing metastatic bone disease and hypercalcemia of malignancy, oral bisphosphonates are the primary treatment for postmenopausal osteoporosis. The availability of a well-tolerated, effective, IV bisphosphonate regimen for postmenopausal osteoporosis would increase physicians' options, allowing treatment of patients who cannot tolerate oral therapy, for whom oral bisphosphonates should be avoided or patients who are unable to comply with the oral dosing recommendations. Ibandronate is a potent, nitrogen-containing bisphosphonate, with proven efficacy and good tolerability when administered intermittently either orally or intravenously. Preclinical experience in animal models with IV ibandronate indicated that it had good renal tolerability. These data are supported by clinical pharmacology studies. Prolonged follow-up of patients receiving intermittent IV 15-30 second injections of 0.5-3 mg IV ibandronate has demonstrated no clinical evidence of renal toxicity in patients with postmenopausal osteoporosis. What is seen in controlled studies is not always the case in uncontrolled studies, however, no reports of renal failure have been received in post-marketing surveillance of >500,000 patients receiving IV ibandronate infusions in various indications including metastatic breast and prostate cancer. The good renal tolerability of IV ibandronate in patients with osteoporosis with glomerular filtration rates >30 mL/minute and without renal co-morbid conditions is reassuring.

Polypeptide p41 of a Norwalk-like virus is a nucleic acid-independent nucleoside triphosphatase

Southampton virus (SHV) is a member of the Norwalk-like viruses (NLVs), one of four genera of the family Caliciviridae. The genome of SHV contains three open reading frames (ORFs). ORF 1 encodes a polyprotein that is autocatalytically processed into six proteins, one of which is p41. p41 shares sequence motifs with protein 2C of picornaviruses and superfamily 3 helicases. We have expressed p41 of SHV in bacteria. Purified p41 exhibited nucleoside triphosphate (NTP)-binding and NTP hydrolysis activities. The NTPase activity was not stimulated by single-stranded nucleic acids. SHV p41 had no detectable helicase activity. Protein sequence comparison between the consensus sequences of NLV p41 and enterovirus protein 2C revealed regions of high similarity. According to secondary structure prediction, the conserved regions were located within a putative central domain of alpha helices and beta strands. This study reveals for the first time an NTPase activity associated with a calicivirus-encoded protein. Based on enzymatic properties and sequence information, a functional relationship between NLV p41 and enterovirus 2C is discussed in regard to the role of 2C-like proteins in virus replication.

A cysteine-rich motif in poliovirus protein 2C(ATPase) is involved in RNA replication and binds zinc in vitro

Protein 2C(ATPase) of picornaviruses is involved in the rearrangement of host cell organelles, viral RNA replication, and encapsidation. However, the biochemical and molecular mechanisms by which 2C(ATPase) engages in these processes are not known. To characterize functional domains of 2C(ATPase), we have focused on a cysteine-rich motif near the carboxy terminus of poliovirus 2C(ATPase). This region, which is well conserved among enteroviruses and rhinoviruses displaying an amino acid arrangement resembling zinc finger motifs, was studied by genetic and biochemical analyses. A mutation that replaced the first cysteine residue of the motif with a serine was lethal. A mutant virus which lacked the second of four potential coordination sites for zinc was temperature sensitive. At the restrictive temperature, RNA replication was inhibited whereas translation and polyprotein processing, assayed in vitro and in vivo, appeared to be normal. An intragenomic second-site revertant which reinserted the missing coordination site for zinc and recovered RNA replication at the restrictive temperature was isolated. The cysteine-rich motif was sufficient to bind zinc in vitro, as assessed in the presence of 4-(2-pyridylazo)resorcinol by a colorimetric assay. Zinc binding, however, was not required for hydrolysis of ATP. 2C(ATPase) as well as its precursors 2BC and P2 were found to exist in a reduced form in poliovirus-infected cells.

Characterization of the nucleoside triphosphatase activity of poliovirus protein 2C reveals a mechanism by which guanidine inhibits poliovirus replication

The highly conserved non-structural protein 2C of picornaviruses is involved in viral genome replication and encapsidation and in the rearrangement of intracellular structures. 2C binds RNA, has nucleoside triphosphatase activity, and shares three motifs with superfamily III helicases. Motifs "A" and "B" are involved in nucleotide triphosphate (NTP) binding and hydrolysis, whereas a function for motif "C" has not yet been demonstrated. Poliovirus RNA replication is inhibited by millimolar concentrations of guanidine hydrochloride (GdnHCl). Resistance and dependence to GdnHCl map to 2C. To characterize the nucleoside triphosphatase activity of 2C, we purified poliovirus recombinant 2C fused to glutathione S-transferase (GST-2C) from Escherichia coli. GST-2C hydrolyzed ATP with a Km of 0.7 mM. Other NTPs, including GTP, competed with ATP for binding to 2C but were poor substrates for hydrolysis. Mutation of conserved residues in motif A and B abolished ATPase activity, as did mutation of the conserved asparagine residue in motif C, an observation indicating the involvement of this motif in ATP hydrolysis. GdnHCl at millimolar concentrations inhibited ATP hydrolysis. Mutations in 2C that confer poliovirus resistant to or dependent on GdnHCl increased the tolerance to GdnHCl up to 100-fold.

Effects of music on exercise and perceived symptoms in patients with chronic obstructive pulmonary disease

BACKGROUND

The purpose of this study was to examine the effects of music on exercise tolerance and perceived symptoms during treadmill walking in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Nineteen patients with COPD recruited from a pulmonary rehabilitation program participated in treadmill walking sessions on three separate days. The first session consisted of a practice walk. The second and third walking sessions were 6-minute timed tests in which the subjects were asked to walk as fast as possible under two conditions: a control walk and a music walk. Subjective assessments of perceived dyspnea and effort were obtained during the walks by the modified Borg scale.

RESULTS

Distances walked were 331m +/- 19 (SE) for the music walk and 321m +/- 21 (SE) for the control walk (P = .25). Within each condition, ratings of perceived exertion and dyspnea increased from minute 1 to minute 6 (P < 0.05).

CONCLUSION

There were no statistically significant differences observed between treatment conditions for distance walked, perceived dyspnea or ratings of perceived exertion. It should be noted that 60% of the subjects voluntarily commented that they enjoyed listening to music while they exercised.

A protein linkage map of the P2 nonstructural proteins of poliovirus

The yeast two-hybrid system was used to catalog all detectable interactions among the P2 nonstructural cleavage products of poliovirus type 1 (Mahoney). Evidence has been obtained for specific associations among 2A(pro), 2BC, 2C, and 2B. Specifically, 2A(pro) can interact with itself and 2BC and its cleavage products (2B and 2C) interact in all possible combinations, with the exception of 2C/2C. Detected interactions were confirmed in vitro by a glutathione S-transferase pulldown assay, which allowed us to detect 2C/2C association. transdominant-negative mutants of 2B (K. Johnson and P. J. Sarnow, J. Virol. 65:4341-4349, 1991) were examined and were found to retain interaction with wild-type 2B, perhaps reflecting a need for 2B multimerization in viral RNA replication. The multimerization of 2B was examined further by screening a mutagenized library for 2B variants that have lost the ability to bind wild-type 2B. The screen identified two nonconservative missense mutations within a central hydrophobic region, as well as truncations and frameshifts that implicate the C terminus in homointeraction. Introduction of the missense mutations into the genome of the virus conferred a quasi-infectious phenotype, an observation strongly suggesting that the 2B/2B interaction is required for replication of the viral genome.

Parathyroid hormone increases the concentration of insulin-like growth factor-I and transforming growth factor beta 1 in rat bone

Intermittent treatment with parathyroid hormone (PTH) increases bone mass in experimental animals and humans. In vitro studies have suggested that the anabolic effect of PTH may be mediated by local growth factors. However, the relevance of these findings to in vivo situations remains unclear. In this study, we examined a time course of daily s.c. injections of hPTH (1-34) on the skeletal concentration of insulin-like growth factor (IGF)-I, IGF-II, and transforming growth factor beta (TGF-beta) in the proximal tail vertebrae of male rats. PTH caused a time and dose-dependent increase in the bone mineral density of the lumbar spine. This anabolic effect on bone mass was accompanied by progressive increases in bone matrix-associated IGF-I and TGF-beta 1. Increases in IGF-I and TGF-beta 1 became apparent after four and eight weeks of PTH treatment respectively and persisted through week 12. PTH had no effect on circulating IGF-I, suggesting that the increase of bone matrix IGF-I was due to the local effect of PTH on bone tissue directly rather than to an increase of circulating IGF-I. These data are consistent with the hypothesis that IGF-I and TGF-beta 1 may play a role as local mediators of the anabolic effects of PTH on bone metabolism.

Poliovirus subviral particles associated with progeny RNA in the replication complex

The poliovirus replication complex (RC), the site of genomic 36S RNA synthesis, was previously shown to contain subviral particles of 5S protomer and 14S pentamer antigenicity. The present investigation demonstrates that 5S/14S antigenic subviral particles can be cross-linked to viral RNA by UV irradiation of a subcellular fraction containing the poliovirus RC. Each capsid protein of the subviral particles, i.e. VP0, VP1 and VP3, was cross-linked to viral RNA. SDS-PAGE analysis of the cross-linked capsid proteins revealed a bandshift for VP1, whereas VP0 migrated in several bands, which were interpreted to be multimers of VP0 linked by short stretches of RNA. It was found that 36S RNA rather than replicative intermediate RNA was cross-linked to capsid proteins. Our results indicate that encapsidation of poliovirus RNA starts in the RC and is initiated by 14S pentamers.

Characteristics of the poliovirus replication complex

In the infected cell, the poliovirus replication complex (RC) is found in the center of a rosette formed by many virus-induced vesicles. The RC is attached to the vesicular membranes and contains a compact central part which encloses the replication forks of the replicative intermediate and all proteins necessary for strand elongation. The growing plus strands of the replicative intermediate protrude from the central part of the RC, but are still enclosed by membraneous structures of the rosette. After completion, progeny 36S RNA is set free at the surface of the rosette. In an in vitro transcription system, isolated replication complex-containing rosettes are active in initiation, elongation and maturation (release) of plus strand progeny RNA. Full functionality of the RC depends on an intact structural framework of all membraneous components of the rosette.

Intracellular localization of poliovirus RNA by in situ hybridization at the ultrastructural level using single-stranded riboprobes

Polioviral RNA was localized by electron microscopic in situ hybridization on sections of poliovirus-infected HEp-2 cells. Viral plus-strand RNA was found accumulated in the close surroundings of the membrane-bound replication complex. Two different regions of the viral genome were detected with the same frequency, which indicates the predominant presence of full-length genomic RNA. Viral proteins of the P2 and the P3 genomic region were detected mainly over the core of the replication complex, whereas the hybridization signal was present rather at the peripheral parts of the complex. A more than 100-fold excess of viral plus- over minus-strand RNA was found by strand-specific hybridization to RNA extracted from isolated replication complexes. These findings support the idea of a pool of viral plus-strand RNA set free from the replication complex and accumulating in the close vicinity of the replication complex possibly before encapsidation.

Immunocytochemical localization of capsid-related particles in subcellular fractions of poliovirus-infected cells

The structural proteins of poliovirus can assemble into a series of different configurations (capsid-related particles, CRP). Only some seem to be true capsid precursors and the role of most CRP in morphogenesis is unclear. We used electron microscopic immunocytochemistry with monoclonal antibodies recognizing different CRP [protomers, pentamers, 65S empty capsids (EC), 74S-EC, and virions] to locate CRP in subcellular fractions containing virus-induced vesicles associated with the viral replication complex. We found pentamer antigenic CRP to be associated with the replication complex. The same pentamer antigenicity was exhibited by novel, "capsid-like" structures attached to the surface of the virus-induced vesicles. Upon solubilization of the vesicular fraction, mainly 65S-EC and only negligible amounts of pentamers were found by sucrose gradient analysis and by immunoprecipitation. We show that the pentamer antigenic particles are converted into 65S-EC when their membranous support is dissolved. We propose that the vesicular membrane prevents the assembly of 65S-EC and keeps the pentamer antigenic CRP in the appropriate concentration and configuration for association with the nascent progeny RNA.

Structural and functional characterization of the poliovirus replication complex

Two populations of membrane-bound replication complexes were isolated from poliovirus-infected HEp-2 cells by sucrose gradient centrifugation. The two fractions show similar ultrastructural features: the replication complex is enclosed in a rosettelike shell of virus-induced vesicles and contains a very tightly packed second membrane system (compact membranes). The vesicular fraction, which bands in 30% sucrose, contains replicative intermediate (RI) and 36S RNA. The fraction banding in 45% sucrose contains only minute amounts of RI and contains mainly 36S RNA, two-thirds of which is encapsidated. In vitro, the two fractions show similar RNA synthesizing capacities and produce 36S plus-strand RNA. Dissolving the membranes within and around synthetically active replication complexes with sodium deoxycholate abolishes the completion of 36S RNA but still allows elongation in the RI. Our findings suggest an architecture of the replication complex that has the nascent plus strands on the RI enclosed in the compact membranes and the replication forks wrapped additionally in protein. Plus-strand RNA can be localized by in situ hybridization with a biotinylated riboprobe between the replication complex and the rosette of the virus-induced vesicles. It was found that the progeny RNA strands are set free soon after completion from the replication complex at the sites where the compact membranes within the replication complex are in close contact with the surrounding virus-induced vesicles.

Cloning and characterisation of an immunodominant major surface antigen of Echinococcus multilocularis

A lambda gt11 cDNA expression library from mRNA of Echinococcus multilocularis protoscolices has been constructed in Escherichia coli Y1090. Immunoscreening with pooled sera obtained from patients suffering from E. multilocularis disease revealed 5 reactive clones. By partial DNA sequence comparison all clones proved to encode the same gene. The complete cDNA sequence of the clone pEM10 with the largest insert of 2.2 kb was determined and an open reading frame of 1.7 kb could be described. The derived amino acid sequence shares 42.6% identity with human microvillar cytovillin found in the membranes of placenta and carcinoma tissues. The coding region of the cDNA of pEM10 was amplified by polymerase chain reaction (PCR) and cloned in frame into expression vector pGEX-3X. Immunoblot analysis revealed the expression of a recombinant antigen of 65 kDa and a protein with the same molecular weight was also found in the lysate of E. multilocularis protoscolices. In contrast, the protein was absent from hydatid fluid or larvae of Echinococcus granulosus. By means of immunofluorescence studies this immunodominant antigen could be located in the germinal layer of brood capsules and in the tegument of E. multilocularis protoscolices. The fusion protein was purified and used for diagnostic purposes in immunoblot. The diagnostic value of this antigen is discussed.

[Toxic epidermal necrolysis (Lyell syndrome)]

Toxic epidermal necrolysis, a serious allergically triggered skin reaction, has a mortality of about 30% largely due to internal diseases. The management involves several specialties. Clinical picture and therapy are described in a case probably induced by allopurinol, with 70% involvement of body surface.