Assessment of the intrasinusidal volume before and after maxillary sinus augmentation using mri - a pilot study of eight patients

PURPOSE

The purpose of this study was to evaluate the suitability, accuracy, and reliability of a non-invasive 3-Tesla magnetic resonance imaging technique (3 T-MRI) for the visualization of maxillary sinus grafts in comparison to conventional, X-ray-based, established standard imaging techniques.

METHODS

A total of eight patients with alveolar bone atrophy who required surgical sinus floor augmentation in the course of dental implantation were included in this pilot study. Alongside pre-operative cone-beam computed tomography (CBCT), 3 T-MRI was performed before and 6 months after sinus floor augmentation. Two investigators measured the maxillary sinus volume preoperatively and after bone augmentation.

RESULTS

In all cases, MRI demonstrated accurately the volumes of the maxillary sinus grafts. Following surgery, the bony structures suitable for an implant placement increased at an average of 4.89 cm3, corresponding with the decrease of the intrasinusidal volumes. In general, interexaminer discrepancies were low and without statistical significance.

CONCLUSION

In this preliminary study, we could demonstrate the feasibility of MRI bone volume measurement as a radiation-free alternative with comparable accuracy to CT/CBCT before procedures like sinus floor augmentation. Nevertheless, costs and artifacts, also present in MRI, have to be taken into account. Larger studies will be necessary to justify the practicability of MRI bone volume evaluation.

AB0139 DEEP IMMUNE PHENOTYPING OF T LYMPHOCYTE SUBSETS IN SYSTEMIC SCLEROSIS PATHOPHYSIOLOGY AND FOLLOWING RESPONSE TO TARGETED CYTOTOXIC TREATMENT

Background

Abnormalities in T lymphocyte populations are associated with the pathogenesis of many autoimmune diseases, such as systemic sclerosis (SSc). Various studies report on the aberrations of different T cell cytotoxic (CTL) and helper (Th) subsets that appear to be linked with inflammatory and/or fibrotic manifestations of patients with SSc. Since T cells seem to play a pivotal role in the pathophysiology of SSc, targeting the pathogenic T cell subsets might be a promising therapeutic option.

Objectives

Here we set out to comprehensively compare T lymphocyte phenotypes between SSc patients and healthy donors. We further test the in-vitro efficacy of a combination of anti-CD3/CD7 immunotoxins (CD3/CD7-IT), that have been developed to eliminate activated CD4+ and CD8+ T cells, to study specific sensitivity of T-cell subpopulations to CD3/CD7-IT.

Methods

30 SSc patients and 15 age and sex matched healthy donors were included. Of these patients, lymphocyte populations were quantified by 17-parameter flow cytometry of peripheral blood mononuclear cells (PBMCs) to identify CD4+ T helper cells (Th1, Th2, Th17, T peripheral helper), CD8+ naïve, memory, effector CTLs and senescent/exhausted subsets. We next developed a cell killing assay to evaluate the effect of T cell depletion. To address this, patients’ (N=6) PBMCs were first activated for 24 hours in the presence of phytohemagglutinin, followed by CD3/CD7-IT addition for 48 hours. Subset-specific T cell depletion was assessed by using a combination of CellTiter-Glow luminescent cell viability assay and multi-parameter flow cytometric (FCM) quantification of CD3/CD7-IT-induced cell death.

Results

Frequencies of effector CD8+ CTLs,Th2 and T peripheral helper cells were elevated in SSc patients compared to healthy controls. Furthermore, SSc patients exhibited lower percentages of the anti-fibrotic Th1 subset. A striking expansion of the senescent CD4+CD28- and CD8+CD28- populations was noted in patients, while these subsets were barely detectable in healthy controls. In-vitro adittion of anti-T cell immunotoxins effectively depleted 50 % of patients’ CD8+ T cells (including the CD8 effector subset) and 62% of CD4+ T cells (including Th2 and T peripheral helper cells). No difference in cytolytic sensitivity between different T cell subsets was observed.

Conclusion

Our findings demonstrate that deep FCM immunephenotyping reveals pathophysiological differences in peripheral T cell subsets of SSc patients. Strikingly, the developed cytolytic assays show that CD3/CD7-IT is able to target the potential disease-associated T cell subsets in an in-vitro setting.

References

Not applicable

Disclosure of Interests

None declared

Living systematic reviews in rehabilitation science can improve evidence-based healthcare

Although systematic reviews are considered as central components in evidence-based practice, they currently face an important challenge to keep up with the exponential publication rate of clinical trials. After initial publication, only a minority of the systematic reviews are updated, and it often takes multiple years before these results become accessible. Consequently, many systematic reviews are not up to date, thereby increasing the time-gap between research findings and clinical practice. A potential solution is offered by a living systematic reviews approach. These types of studies are characterized by a workflow of continuous updates which decreases the time it takes to disseminate new findings. Although living systematic reviews are specifically designed to continuously synthesize new evidence in rapidly emerging topics, they have also considerable potential in slower developing domains, such as rehabilitation science. In this commentary, we outline the rationale and required steps to transition a regular systematic review into a living systematic review. We also propose a workflow that is designed for rehabilitation science.

POS1096 THE EFFECT OF ONE DRY NEEDLING SESSION ON PAIN AND CENTRAL PAIN PROCESSING IN PATIENTS WITH KNEE OSTEOARTHRITIS: A RANDOMIZED CONTROLLED TRIAL

Background:

Osteoarthritis (OA) is the leading cause of chronic disability in the elderly1,2. Abnormal central pain processing (CPP) is present in around 30% of the knee OA patients3 and can be partly induced by peripheral nociception through long term potentiation4. An attempt to resolve abnormal CPP can be to eliminate this nociception5. Myofascial trigger points (MTrPs) are often present in knee OA6, can lead to nociception7 and therefore abnormal CPP if prolonged present8. These are usually defined as hypersensitive tender spots within taut bands of a muscle9. Additionally, both MTrPs and knee OA can induce disturbed motor control, increased co-antagonist activation and modified gait pattern10,11. Dry needling (DN) is often used to deactivate the MTrP and thus resolve the source of nociception, which normally results in reducing pain and restoring muscle dysfunction12. However, studies about the effect of DN on CPP and other outcomes than pain are very limiting. Therefore, more high-quality studies concerning DN and its effects on CPP, muscle features and gait are needed13,14.

Objectives:

The aim of this randomized controlled trial is to assess the effect of one DN session compared to one sham needling (SN) session on pain (processing), muscle activity and gait in patients with knee OA.

Methods:

61 patients participated of which 31 were allocated to the DN and 30 to the SN group. Each patient underwent one treatment session. Primary outcomes were pain intensity, measured with questionnaires; and CPP, measured with quantitative sensory testing. Secondary outcomes included muscle co-activation, measured with electromyography; and spatiotemporal parameters, measured with gait analysis. Patients were assessed at baseline, 15 minutes (post 1) and 3 days after intervention (post2- only for the outcome pain). Linear mixed models was used to identify the possible differences over time between the two therapy modalities.

Results:

The following significant within group differences were observed: decreased pain, stride- and step time and increased widespread pain pressure threshold and step length. A significant between group difference of the conditioned pain modulation score was found, whereas the SN group showed a decrease in difference between the pain pressure threshold scores (with and without conditioning stimulus) and the DN group remained stable. No other significant between or within group differences were detected. However, if we compared both interventions, the change over time for the visual analogue scale (VAS) behaved different in the DN (p<0.05, post 2 - baseline) and SN group (p<0.05, post 1 - baseline and post 2 - post 1).

Conclusion:

One DN session has no larger effect on all outcome measurements compared to SN. Both therapies seem to be useful to improve pain and widespread pain pressure threshold in short term, however the improvement of pain differs in the groups. Although improvements in some spatiotemporal parameters were observed, it is uncertain they are of clinical relevance or related to treatment. More research is necessary to reveal the ideal number of sessions of DN to improve outcomes and to reveal the effect of DN compared to no treatment, as SN could have hide the real treatment effect.

References:

[1]Reginster, J. Y. Rheumatol. Oxf. 41 Supp 1, 3–6 (2002)

[2]Lespasio, M. J. et al. Perm J 21, 16–183 (2017)

[3]Lluch, E. et al. Eur J Pain 18, 1367–75 (2014)

[4]Mease, P. J. et al. J. Rheumatol. 38, 1546–1551 (2011)

[5]Nijs, J. et al. Expert Opin Pharmacother 15, 1671–83 (2014)

[6]Bajaj, P. et al. J. Musculoskelet. Pain 9, 17–33 (2001)

[7]Jafri, M. S. Int. Sch. Res. Not. 2014, (2014)

[8]Cagnie, B. et al. Curr Pain Headache Rep 17, 348 (2013)

[9]Borg-Stein, J. et al. Arch. Phys. Med. Rehabil. 83, S40–S47 (2002)

[10]Childs, J. D. et al. Clin. Biomech. 19, 44–9 (2004)

[11]Ibarra, J. M. et al. J Pain 12, 1282–8 (2011)

[12]Rahou-El-Bachiri, Y. et al. J. Clin. Med. 9, (2020)

[13]Stieven, F. F. et al. J. Manipulative Physiol. Ther. (2021)

[14]Dor, A. et al. J Bodyw Mov Ther 21, 642–647 (2017)

Figure 1.

Mean and standard error of VAS scores over time in the DN and SN group

Acknowledgements:

I like to thank and acknowledge the contribution of the other executive researchers (Lise Brosens, Ayoub El Bouchaoni, Ben Ceusters, Sven Huybrechts and Mathias Van Loon), the participated dry needling therapists, Dry Needling Ghent, Trigger and the University Hospital of Antwerp.

Disclosure of Interests:

None declared.

Comparative analysis of biofilm models to determine the efficacy of antimicrobials

Biofilms are one of the greatest challenges in today's treatment of chronic wounds. While antimicrobials kill platonic bacteria within seconds, they are rarely able to harm biofilms. In order to identify effective substances for antibacterial therapy, cost-efficient, standardized and reproducible models that aim to mimic the clinical situation are required. In this study, two 3D biofilm models based on human plasma with immune cells (lhBIOM) or based on sheep blood (sbBIOM) containing S. aureus or P. aeruginosa, are compared with the human biofilm model hpBIOM regarding their microscopic structure (scanning electron microscopy; SEM) and their bacterial resistance to octenidine hydrochloride (OCT) and a sodium hypochlorite (NaOCl) wound-irrigation solution. The three analyzed biofilm models show little to no reaction to treatment with the hypochlorous solution while planktonic S. aureus and P. aeruginosa cells are reduced within minutes. After 48 h, octenidine hydrochloride manages to erode the biofilm matrix and significantly reduce the bacterial load. The determined effects are qualitatively reflected by SEM. Our results show that both ethically acceptable human and sheep blood based biofilm models can be used as a standard for in vitro testing of new antimicrobial substances. Due to their composition, both fulfill the criteria of a reality-reflecting model and therefore should be used in the approval for new antimicrobial agents.

Return to work guidance within cardiac rehabilitation: content and costs of two settings compared

Background

Of those who survived a cardiac event and participated in cardiac rehabilitation (CR), many experience labor participation restrictions. The Dutch CR guideline includes return to work (RTW) guidance but no directives on where CR has to be offered. The aim was to compare rehabilitation centre and hospital based CR regarding 1) how RTW guidance was organised, 2) changes after CR in sickness absence and quality of life, 3) costs.

Methods

The study was designed as an exploratory cost-outcome description with naturalistic design. Care was assessed at the level of CR in a specialised rehabilitation centre and a hospital. The study population consisted of 116 employed cardiovascular patients (19-63 years of age) of one hospital referred to out-patient level II CR (for complex pathology), either at a rehabilitation centre (n = 53) or at the hospital (n = 63). Information on RTW guidance was obtained by interviews with the CR coordinators. Survey data from patients were collected at baseline, six and twelve months.

Results

At baseline, patient groups did not differ apart from sickness absence being higher in the rehabilitation centre group (76 versus 19 days in previous half year). RTW guidance within CR consisted of individual-based therapy including occupational therapy in the rehabilitation centre, and group-based therapy in the hospital. Costs of RTW guidance in the rehabilitation centre were estimated at €1,892.30, versus €296.82 in the hospital (net difference of €1,595.48). Sickness absence increased during CR for the hospital group, and decreased for both groups after twelve months (with 55 and 7 days, respectively); Quality of Life did not change.

Conclusions

Costs of CR at the rehabilitation centre were more than six times higher than in the hospital. Patients in the rehabilitation centre might have needed the more intensive RTW guidance. Cost-effectiveness research is needed to confirm if the guideline should include stricter targeting.

Key messages

Costs of return to work guidance within cardiac rehabilitation are higher at a rehabilitation centre than in a hospital. Further research on whether costs outweigh effects of return to work guidance at rehabilitation centres and hospitals is needed.

Practitioner experience with sonic osteotomy compared to bur and ultrasonic saw: a pilot in vitro study

The aim of the present study was to compare subjective experiences using bur, ultrasonic, and sonic osteotomy systems. Ten novice (N) and 10 expert (E) practitioners performed osteotomies on bovine ribs with each system. They scored ease of handling and sense of accuracy on visual analogue scales. The duration of the osteotomy procedure and the amount of noise were recorded objectively. Learning experience was evaluated in a second run. The Mann-Whitney U-test, Wilcoxon signed rank tests, and Spearman's rank correlation coefficient were used for the statistical analyses. The sonic system was significantly slower, with the worst noise impact (92.9dB; standard deviation (SD) 7.1). However, both user groups improved significantly in the second run (N 7.9, E 7.6). There were no significant differences in handling. The sense of accuracy was evaluated to be significantly best for the sonic system (N 8.4, E 8.4), compared to the ultrasonic system (N 7.1, E 7.1; both P=0.043) and bur system (N 5.5, P=0.002; E 6.0, P=0.006). The practitioners had a promising experience with the application of the ultrasonic system and particularly with the sonic system.

Oral cytology revisited

During the last decade, oral cytology has once again become the focus of scientific research. This new interest is due to the introduction of a cytobrush for cell collection as well as a computer-assisted analysis (Oral CDx). Although promising, the sensitivity and specificity of conventional oral brush cytology remains limited. To circumvent the problems and improve the accuracy, various adjunctive analytical methods have been attempted. DNA analysis, immunocytochemical and molecular analysis are suggested methodological cytology approaches to improve the validity of oral brush cytology. An increase in sensitivity (up to 100%) and specificity (up to 100%) of oral brush biopsy has been reported on localized pre-malignant and malignant lesions. Oral brush biopsy probably will not replace histopathology in the definitive diagnosis of oral cancer, but it might be valuable for the prevention of misdiagnosis of clinically doubtful oral lesions and for the monitoring of lesions that might proceed on to oral cancer.

Single nucleotide polymorphism in esophageal cancer related gene 1: an analysis in resected oral squamous cell carcinoma patients

Esophageal cancer related gene 1 (ECRG1) is a novel candidate tumor suppressor gene in human esophageal squamous cells. Overexpression of ECRG1 protein inhibits tumor cell proliferation. Genetic polymorphisms in coding sequences of the gene may cause functional alterations of the gene product and be associated with higher cancer risk and disease phenotypes. A single nucleotide polymorphism (SNP) (Arg290Gln) found in the coding region of ECRG1 might play a role in susceptibility to esophageal squamous cell carcinoma. This study examined SNPs in ECRG1 in a similar tumor type (oral squamous cell carcinoma; OSCC) and investigated the relationship between SNPs in ECRG1 and the clinical outcome of patients with OSCC. DNA samples of 137 OSCC patients were analyzed for SNP genotypes Arg/Arg, Arg/Gln and Gln/Gln in the coding region (exon 8) of ECRG1. SNP genotypes Arg/Arg were found in 70 (51%), Arg/Gln in 60 (43%) and Gln/Gln in 7 (5%) patients. There was no significant association between genotypes and survival (p=0.77) or relapse free survival (p=0.32). The Gln/Gln genotype had the best survival (not significant) probably due to rare cases of SNP Gln/Gln genotype. Genotype Arg/Arg might be a potential negative prognostic marker in OSCC, but more studies with higher patient numbers are required.

Beneficial effect of corticosteroids in catecholamine-dependent septic burn patients

Recent studies indicated the benefit of hydrocortisone in septic patients based on the significant reduction of catecholamines and improved outcome in common intensive care patients. The treatment of intensive care burn patients with corticosteroids was discussed with great caution due to the especially compromised immune status of severely burned patients. The purpose of this study was to investigate the influence of corticosteroids in burn patients during septic shock. In our burn unit, we started with the administration of cortisol in 2001. In this retrospective study, 10 severely burned patients received, > or = 24h after norepinephrine dependency, hydrocortisone infusions of 200 mg/24 h. The course of norepinephrine dose, hemodynamic measurements (Swan-Ganz-Catheter) and daily Sequential Organ Failure Assessment (SOFA-Score) were analyzed and compared to nine (catecholamine-dependent) burn patients without cortisol therapy. Statistical analysis by means of Fisher's Exact Test revealed beneficial effects (morbidity and mortality) of low dose cortisol therapy compared to control patients. However, the results of this study must be interpreted with caution because of its limited number of patients and its retrospective character. Further randomized prospective controlled studies are necessary to determine the efficacy and safety of cortisol therapy in burn patients.

Analysis of mitochondrial DNA sequences in patients with isolated or combined oxidative phosphorylation system deficiency

BACKGROUND

Enzyme deficiencies of the oxidative phosphorylation (OXPHOS) system may be caused by mutations in the mitochondrial DNA (mtDNA) or in the nuclear DNA.

OBJECTIVE

To analyse the sequences of the mtDNA coding region in 25 patients with OXPHOS system deficiency to identify the underlying genetic defect.

RESULTS

Three novel non-synonymous substitutions in protein-coding genes, 4681T-->C in MT-ND2, 9891T-->C in MT-CO3 and 14122A-->G in MT-ND5, and one novel substitution in the 12S rRNA gene, 686A-->G, were found. The definitely pathogenic mutation 3460G-->A was identified in an 18-year-old woman who had severe isolated complex I deficiency and progressive myopathy.

CONCLUSIONS

Bioinformatic analyses suggest a pathogenic role for the novel 4681T-->C substitution found in a boy with Leigh's disease. These results show that the clinical phenotype caused by the primary Leber's hereditary optic neuropathy mutation 3460G-->A is more variable than has been thought. In the remaining 23 patients, the role of mtDNA mutations as a cause of the OXPHOS system deficiency could be excluded. The deficiency in these children probably originates from mutations in the nuclear genes coding for respiratory enzyme subunits or assembly factors.

Fumarase deficiency presenting with periventricular cysts

A fumarase-deficient patient expressed a novel phenotype of congenital cerebral ventricular dilatation and periventricular cysts. The patient was a compound heterozygote for two mutations that are the only ones among the 12 published mutations that have been found in multiple, unrelated, fumarase-deficient patients.

Mutation detection in four candidate genes (OXA1L, MRS2L, YME1L and MIPEP) for combined deficiencies in the oxidative phosphorylation system

Mitochondria are the main energy-producing organelles of the cell. Five complexes embedded in the mitochondrial inner membrane, together constituting the oxidative phosphorylation (OXPHOS) system, comprise the final steps in cellular energy production. Many patients with a mitochondrial defect suffer from a so-called combined deficiency, meaning that the enzymatic activities of two or more complexes of the OXPHOS system are decreased. Numerous mutations have been described in nuclear genes that are involved in the functioning of a single complex of the OXPHOS system. However, little attention has been paid to patients with a deficiency of more than one complex of this particular system. In this study we have investigated four nuclear genes (OXA1L, MRS2L, YME1L and MIPEP) that might be involved in the pathology of combined enzymatic deficiencies of the OXPHOS system. Based on the results of yeast knockouts of these four proteins, we have sequenced the open reading frame of OXA1L in eight patients with an enzymatic deficiency of complexes I and IV. MRS2L, YME1L and MIPEP have been sequenced in three patients with a combined defect of complexes III and IV. No mutations were detected in these patients, showing that at least in these patients the OXPHOS system deficiency cannot be explained by a mutation in these four genes.

Human mitochondrial complex I deficiency: investigating transcriptional responses by microarray

NADH:ubiquinone oxidoreductase (complex I) deficiency is one of the most frequently encountered defects of the mitochondrial energy generating system. A deficiency of this enzyme complex leads to a wide variety in clinical disease expression. The cell biological consequences of such mutations, however, are poorly understood. We investigated transcriptional responses in fibroblast cell lines harboring mutations in the five different nuclear DNA encoded subunits using a mitochondria-targeting microarray. Expression profiles of cell lines cultured under conditions that favor glycolytic metabolism were compared to profiles when cultured under conditions favoring oxidative metabolism. Approximately 60 genes displayed differential expression under these conditions in either all mutated cell lines or selected cell lines only. A marked induction of metallothioneins as well as ATP1G1 transcripts was detected in all patient cell lines. Transcriptional responses such as the induction of heat shock protein transcripts, decreased PDK1,BNIP3 and mitochondrial genome encoding gene transcripts occurred in selected patient cell lines. The observed transcript profile points to a common, putative defensive, response relating to oxidative stress. Although further investigations of other human OXPHOS system diseases is warranted, these results clearly underline that functional genomics holds for the study of inherited metabolic disease.

Effects of oral bovine colostrum supplementation on serum insulin-like growth factor-I levels

OBJECTIVES

We investigated whether supplementation with 60 g/d of bovine colostrum affects blood levels of insulin-like growth factor-I (IGF-I) and IGF binding protein-3 in relation to doping testing. Nine endurance-trained men ingested 60 g/d of bovine colostrum for 4 wk.

METHODS

Blood and urine were sampled before starting supplementation. After 4 wk urine and blood samples were taken after an overnight fast and 2 h after ingestion of the last portion to study possible acute effects.

RESULTS

Blood IGF-I levels before supplementation were (mean +/- standard deviation) 31 +/- 13 nM/L, and no acute effects were observed after 4 wk of supplementation (33 +/- 9 nM/L). Levels of IGF-binding protein-3 were 136 +/- 11 nM/L before supplementation and 135 +/- 16 nM/L after 4 wk of supplementation. Two hours after ingestion of the last portion, the level of IGF binding protein-3 was 131 +/- 19 nM/L, which was not different from baseline values. Drug testing in a laboratory accredited by the International Olympic Committee did not show any forbidden substance before or after 4 wk of supplementation.

CONCLUSIONS

Daily supplementation with 60 g of bovine colostrum for 4 wk does not change blood IGF-I or IGF binding protein-3 levels and does not elicit positive results on drug tests.

Mutations in the complex I NDUFS2 gene of patients with cardiomyopathy and encephalomyopathy

Human complex I is built up and regulated by genes encoded by the mitochondrial DNA (mtDNA) as well as the nuclear DNA (nDNA). In recent years, attention mainly focused on the relation between complex I deficiency and mtDNA mutations. However, a high percentage of consanguinity and an autosomal-recessive mode of inheritance observed within our patient group as well as the absence of common mtDNA mutations make a nuclear genetic cause likely. The NDUFS2 protein is part of complex I of many pro- and eukaryotes. The nuclear gene coding for this protein is therefore an important candidate for mutational detection studies in enzymatic complex I deficient patients. Screening of patient NDUFS2 cDNA by reverse transcriptase-polymerase chain reaction (RT-PCR) in combination with direct DNA sequencing revealed three missense mutations resulting in the substitution of conserved amino acids in three families.

Characterization of the human complex I NDUFB7 and 17.2-kDa cDNAs and mutational analysis of 19 genes of the HP fraction in complex I-deficient-patients

Deficiency of NADH:ubiquinone oxidoreductase, the first enzyme complex of the mitochondrial respiratory chain, is one of the most frequent causes of human mitochondrial encephalomyopathies. A relatively small percentage of human complex I deficiency is associated with mitochondrial DNA mutations. cDNA characterization and mutational analysis of the structural complex I genes in 19 complex I-deficient patients, in whom common mtDNA mutations have been excluded, has so far revealed five patients with alterations in evolutionary conserved nuclear-encoded proteins. In order to complete our knowledge about the expected 36 structural nuclear complex I genes, we characterized the NDUFB7 and the 17.2-kDa cDNA sequences of the hydrophobic (HP) fraction of the complex. Subsequently, we screened all subunits of this fraction for the presence of mutations in those 14 patients of our initial patient cohort in whom the underlying genetic cause had not been elucidated. Strikingly, no pathogenic mutations were found in the HP subunits that would explain the complex I deficiency in our patients. Other strategies are needed to unravel proteins involved in the pathogenesis of the complicated cellular network of transcription until correct assemblage of complex I.

Validating a decision support system for anti-epileptic drug treatment. Part I: initiating anti-epileptic drug treatment

In this contribution the validation of a prototype decision support system that implements a model of expertise for initiating anti-epileptic drug treatment is described. Since domain experts were of the opinion that prescribing was a rather straightforward process we used only one expert neurologist for knowledge elicitation. To determine the correctness of the system we intended to compare the contents of the system's prescriptions with the majority decision of three neurologists. Because of a large variation in prescribing a majority decision could not be obtained in many cases. Even a Delphi procedure did not yield a majority decision in a large number of cases. Therefore a consensus meeting was organised to discuss cases where discrepancies remained. In the process the participating neurologists formulated prescription guidelines. These guidelines were used as a reference to determine the correctness of the prescriptions of both the system and of the neurologists. The acceptability of all prescriptions for each case was rated by the two neurologists who did not write a prescription for that case. From both comparisons it could be concluded that the system was at least as good in prescribing as individual neurologists.

Validating a decision support system for anti-epileptic drug treatment. Part II: adjusting anti-epileptic drug treatment

A model of expertise for monitoring antiepileptic drug treatment was implemented in a decision support system. We validated the advice of the system regarding treatment decisions at first follow-up with 265 paper cases based on patient records. The reference for comparison is based on the opinions of neurologists. We found considerable variation among the decisions of five neurologists. It could be shown that the system agreed with (groups of) neurologists at least as often as individual neurologists did. The correctness of the system was consistently higher than that of each of the neurologists, when the majority decision of the remaining neurologists constituted the standard.

Agreement and correctness in adjusting antiepileptic drug treatment: a need for rational drug treatment?

PURPOSE

To study interobserver variation in treatment decisions in a first follow-up contact after initiation of antiepileptic drug (AED) treatment. The results should aid us in the assessment of whether decision support can be of value in this situation.

METHODS

Data from patient records were used to construct 270 different test cases containing information about the course of the disease after initiation of drug treatment. The cases were presented to five neurologists from different general hospitals who previously agreed about the diagnosis and the initial treatment for these cases. They were asked to write a prescription for each test case.

RESULTS

All five neurologists agreed on a treatment decision in 21.9% of the 265 cases available for analysis. Each neurologist made a decision different from the decisions taken by all other neurologists in 14.0-19.6% of the cases. Kappa values for agreement among individual neurologists as well as for agreement between an individual and the group of his peers were low. In 82.6% of the cases, a majority of the neurologists agreed on a treatment decision. Comparing the decisions of individual neurologists with the majority decision reference (219 cases) showed a significant difference in correctness (range, 67.1-82.6%) among the neurologists.

CONCLUSIONS

The fact that a majority decision could be reached in a considerable number of cases, as well as the variability in adjustment of an initiated drug treatment, leads us to the conclusion that decision support can contribute to a rational adjustment of drug treatment.

The human nuclear-encoded acyl carrier subunit (NDUFAB1) of the mitochondrial complex I in human pathology

We present the cDNA sequence of the human mitochondrial acyl carrier protein NDUFAB1, a nuclear-encoded subunit of complex I of the mitochondrial respiratory chain. We obtained the NDUFAB1 cDNA using the cDNA sequence of the bovine mitochondrial acyl carrier protein. The human cDNA contains two putative translation initiation codons. The human NDUFAB1 protein contains a phosphopantetheine attachment site (DLGLDSLDQVEIIMAM), unique for acyl carrier proteins, and an EF-hand calcium binding domain (DIDAEKLMCPQEI). Transcripts of this gene are found in a wide range of human tissues. The highests expression levels were observed, in descending order, in adult heart, skeletal muscle and fetal heart. We subjected NDUFAB1 fibroblast cDNA of 20 patients with an isolated enzymatic complex I deficiency to mutational detection. No mutations in the NDUFAB1 open reading frame were observed. Future studies will answer whether mutations in the NDUFAB1 promoter or transcription elements are responsible for the observed complex I deficiency.

The human NADH: ubiquinone oxidoreductase NDUFS5 (15 kDa) subunit: cDNA cloning, chromosomal localization, tissue distribution and the absence of mutations in isolated complex I-deficient patients

We have cloned the cDNA of the NDUFS5 subunit (15 kDa) of the human mitochondrial respiratory chain complex NADH: ubiquinone oxidoreductase (complex I). The open reading frame consists of 321 base-pairs, coding for 106 amino acids, with a calculated molecular mass of 12.5 kDa. There is an 81.0% identity with the bovine equivalent on cDNA level and 74.5% identity on amino acid basis. PCR analysis of rodent-human somatic cell hybrids revealed that the human NDUFS5 gene maps to chromosome 1. The NDUFS5 mRNA is expressed ubiquitously in human tissues, with a relative higher expression in human heart, skeletal muscle, liver, kidney and fetal heart. A mutation detection study of twenty isolated enzymatic complex I-deficient patients revealed no mutations, nor polymorphisms.

The first nuclear-encoded complex I mutation in a patient with Leigh syndrome

Nicotinamide adenine dinucleotide (NADH):ubiquinone oxidoreductase (complex I) is the largest multiprotein enzyme complex of the respiratory chain. The nuclear-encoded NDUFS8 (TYKY) subunit of complex I is highly conserved among eukaryotes and prokaryotes and contains two 4Fe4S ferredoxin consensus patterns, which have long been thought to provide the binding site for the iron-sulfur cluster N-2. The NDUFS8 cDNA contains an open reading frame of 633 bp, coding for 210 amino acids. Cycle sequencing of amplified NDUFS8 cDNA of 20 patients with isolated enzymatic complex I deficiency revealed two compound heterozygous transitions in a patient with neuropathologically proven Leigh syndrome. The first mutation was a C236T (P79L), and the second mutation was a G305A (R102H). Both mutations were absent in 70 control alleles and cosegregated within the family. A progressive clinical phenotype proceeding to death in the first months of life was expressed in the patient. In the 19 other patients with enzymatic complex I deficiency, no mutations were found in the NDUFS8 cDNA. This article describes the first molecular genetic link between a nuclear-encoded subunit of complex I and Leigh syndrome.