Feasibility of EPID Based In Vivo Dosimetry for On-Couch Adaptive Radiotherapy

PURPOSE/OBJECTIVE(S)

CBCT-based online adaptive radiotherapy allows treatment plans to be tailored to the anatomy of the day. For this purpose, dose optimization and computation are performed on a synthetic CT (sCT), i.e., a density map of the planning CT deformably registered onto the acquired CBCT. Plan-specific quality assurance of adaptive treatment sessions is currently limited to the vendors own secondary dose calculation on the sCT. The use of EPID recordings promises to detect deviations in beam delivery or patient position, incorrect sCT data and anatomical changes. The purpose of this research was to evaluate the feasibility of using a new commercial technology available for in-vivo dose reconstruction based on EPID exit beam measurements.

MATERIALS/METHODS

EPID images were recorded from on-couch adapted, hypofractionated treatment plans created for a prostate patient. Secondary dose calculation of the adapted plan and 3D reconstructions from EPID images of the absolute dose delivered to the patient were performed with the in-vivo dosimetry system. Comparison of reconstructed and planned delivery was conducted by means of gamma analysis and DVH metrics.

RESULTS

Comparisons of the intended plan to a second volumetric check (collapsed cone - CC algorithm), and to the EPID in-vivo calculation, produced gamma passing rates averaged over the 7 fractions of 98.3% and 88.8% at TG-218/219 recommended criteria (Table 1). DVH metrics showed average deviations of -2.9% / -3.3% for PTV D95% and -1.2% / -0.2% for PTV D50% between intended dose and secondary / EPID in-vivo dose. The pronounced discrepancies for fraction 3 in terms of both reduced gamma passing rates and increased deviations for the EPID reconstructed dose coincide with a large air cavity in the rectum showing up in the patient's CBCT prior to treatment. Secondary dose calculation based on the density information of the CBCT as an additional option for QA confirmed origin and magnitude of this effect.

CONCLUSION

In-vivo EPID dosimetry of adaptive clinical plans is feasible. It was shown exemplary that it reveals fractions with noticeable anatomical changes between the sCT and the patient anatomy during treatment. As new recommendations were published on in-vivo dosimetry through TG 307, the development of new clinical tools and evaluation of existing commercial solutions is essential, also in the context of the growing use of on-couch adaptive technology.

Endovascular therapy outcome in isolated posterior cerebral artery occlusion strokes: A multicenter analysis of the Swiss Stroke Registry

PURPOSE

There is little data on the safety and efficacy of endovascular treatment (EVT) in comparison with intravenous thrombolysis (IVT) in acute ischemic stroke due to isolated posterior cerebral artery occlusion (IPCAO). We aimed to investigate the functional and safety outcomes of stroke patients with acute IPCAO treated with EVT (with or without prior bridging IVT) compared to IVT alone.

METHODS

We did a multicenter retrospective analysis of data from the Swiss Stroke Registry. The primary endpoint was overall functional outcome at 3 months in patients undergoing EVT alone or as part of bridging, compared with IVT alone (shift analysis). Safety endpoints were mortality and symptomatic intracranial hemorrhage. EVT and IVT patients were matched 1:1 using propensity scores. Differences in outcomes were examined using ordinal and logistic regression models.

FINDINGS

Out of 17,968 patients, 268 met the inclusion criteria and 136 were matched by propensity scores. The overall functional outcome at 3 months was comparable between the two groups (EVT vs IVT as reference category: OR = 1.42 for higher mRS, 95% CI = 0.78-2.57, p = 0.254). The proportion of patients independent at 3 months was 63.2% in EVT and 72.1% in IVT (OR = 0.67, 95% CI = 0.32-1.37, p = 0.272). Symptomatic intracranial hemorrhages were overall rare and present only in the IVT group (IVT = 5.9% vs EVT = 0%). Mortality at 3 months was also similar between the two groups (IVT = 0% vs EVT = 1.5%).

CONCLUSION

In this multicenter nested analysis, EVT and IVT in patients with acute ischemic stroke due to IPCAO were associated with similar overall good functional outcome and safety. Randomized studies are warranted.

Outcomes after reperfusion therapies in patients with ACA stroke: A multicenter cohort study from the EVATRISP collaboration

BACKGROUND

Patients with stroke secondary to occlusions of the anterior cerebral artery (ACA) often have poor outcomes. The optimal acute therapeutic intervention for these patients remains unknown.

METHODS

Patients with isolated ACA-stroke were identified from 10 centers participating in the EndoVascular treatment And ThRombolysis in Ischemic Stroke Patients (EVATRISP) prospective registry. Patients treated with endovascular thrombectomy (EVT) were compared to those treated with intravenous thrombolysis (IVT). Odds ratios with 95% confidence intervals (OR; 95%CI) were calculated using multivariate regression analysis.

RESULTS

Included were 92 patients with ACA-stroke. Of the 92 ACA patients, 55 (60%) were treated with IVT only and 37 (40%) with EVT (±bridging IVT). ACA patients treated with EVT had more often wake-up stroke (24% vs. 6%, p = 0.044) and proximal ACA occlusions (43% vs. 24%, p = 0.047) and tended to have higher stroke severity on admission [NIHSS: 10.0 vs 7.0, p = 0.054). However, odds for favorable outcome, mortality or symptomatic intracranial hemorrhage did not differ significantly between both groups. Exploration of the effect of clot location inside the ACA showed that in patients with A1 or A2/A3 ACA occlusions the chances of favorable outcome were not influenced by treatment allocation to IVT or EVT.

DISCUSSION

Treatment with either IVT or EVT could be safe with similar effect in patients with ACA-strokes and these effects may be independent of clot location within the occluded ACA.

A data-pipeline processing electrocardiogram recordings for use in artificial intelligence algorithms

Introduction

Artificial intelligence (AI) can be used for various tasks in medicine and specifically in cardiology. Medical data such as electrocardiogram recordings (ECGs) are widely used and universally accepted as diagnostic and prognostic tools. It has been shown that deep learning methods using ECGs yield excellent results detecting cardiac pathologies. A significant amount of reliable data is required for supervised learning algorithms such as deep learning models. However, only a small fraction of ECG data generated in daily practice is available in a fully digital and machine-readable format, such as XML. Frequently, used ECG devices produce PDF files or even paper-based print outs, which need to be digitised later for inclusion in clinical information systems. Such ECGs cannot be used without further effort for training or application of deep learning models. Therefore, aim of the present project was to develop a data-pipeline that generates machine-readable ECG data for AI use data irrespective of the initial ECG format.

Methods

We propose an end-to-end pipeline that can not only process data from modern digital ECG devices but is also capable of extracting all necessary information from PDF files (both scanned hard copies and digitally generated PDFs) (see Figure 1). By using different techniques including adaption of open source libraries for vectorisation of image data, and modern computer vision technologies, such as optical character recognition (OCR), our pipeline is able to flexibly process data from different recording devices and read both data in PDF format and data from native digital devices delivered in XML. The processed files from various sources are either saved as a common and easily accessible CSV file format, or are processed directly with deep learning models (see Figure 2).

Results

The developed data-pipeline was validated using data from a set of 113 12-lead ECGs for which data was available in multiple formats. Each format dataset was separately processed by our pipeline and then used for training and validation of a deep learning architecture for myocardial scar detection based on raw ECG signals. The quality of the extraction process by our pipeline was assessed by the respective deep learning models with their prediction capability depicted by receiver operator characteristic analyses (ROC). Comparing the benchmark model that was generated from XML data against a model that was purely trained on PDF data processed by the pipeline shows that both models produced comparable results, reaching area under the curve (AUC) values of 0:79±0:10 (XML) and 0:83±0:07 (PDF).

Conclusion

The data pipeline facilitates acceleration of ECG-based AI research and application of AI algorithms by providing access to ECG data irrespective of the format of the stored ECG. Future work will focus on independent validation as well as expanding this pipeline to include additional ECG types.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Flexi Funds by Forschungscampus Mittelhessen

On the importance of representative datasets in ECG-based artificial intelligence

Background/Introduction

ECG-based artificial intelligence (AI) is an emerging field in digital cardiology. Training on diseased records vs. healthy controls is common practice. We aimed to evaluate if such an approach can lead to unwanted behaviour in real-world settings and thus unnecessarily reduce diagnostic precision of the developed AI model.

Purpose

Several studies have shown that deep neural networks are able to exceed performance of medical experts. However, when these models are applied to different cohorts, results vary strongly. We hypothesise that this is because the datasets used for training were not representative for the target population.

Methods

Based on the public ECG database PTB-XL we sampled three distinct subsets of n=150 records representing ECG groups labelled for diagnoses 'old myocardial infarction' (M), 'normal ECG' (N), or 'other cardiac abnormality' (O). These groups were combined to three datasets ([M, N] (n=300), [M, O] (n=300), [M, N, O] (n=450)), representing different approaches to data sampling. On each dataset, we trained a separate but equally structured deep neural network using 100-fold bootstrapping. The diagnostic performance of each model was validated on unseen data from all datasets with sensitivity, specificity and area under the receiver operator characteristic curve.

Results

Evaluation of the three differently trained models shows best diagnostic performance on the M vs. N records and worst on the M vs. O records. However, in the out-of-dataset setting, the best-performing model (trained on [M, N]) shows weaker performance on the [M, N, O] and [M, O] datasets. Sensitivity for the same model remained equal, as identical M records were used throughout corresponding bootstrapping folds. Detailed results are presented in Table 1.

Conclusions

Our results suggest that the model trained on a dataset including only diseased records vs. healthy controls [M, N] learned to recognise healthy (N) instead of diseased (M) records, which explains why it performed poorly on datasets including records showing other cardiac abnormalities (O). Such behaviour is a common problem in AI and requires special attention in dataset sampling. For small cohorts, it is tempting to increase the amount of training data by using healthy controls. However, we have shown that this can be a poor option, since classifiers can more easily rely on features that are not actually related to the target disease. Training and validation of classifiers should therefore be performed on representative datasets that are as close as possible to the target population.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Forschungscampus Mittelhessen, Flexi Funds Table 1

Predicting mortality in cardiovascular patients using electrocardiogram data and artificial intelligence

Background/Introduction

The electrocardiogram (ECG) is an ubiquitously used non-invasive tool for diagnosis and risk prediction in cardiology, granting deep extensive insights into the heart. Artificial intelligence (AI) is a modern resource allowing the processing of vast complex datasets in a way that is comparable to humans. Risk stratification in cardiovascular patients is mainly based on scoring systems, such as the ESC-SCORE, relying on traditional risk variables like cholesterol levels or arterial hypertension, rather than actual cardiac structure and function. Goal of this project was to predict mortality using AI in patients with cardiovascular risk based on the current cardiac situation represented by a standard 12-lead ECG recording.

Methods

The study population is based on an ongoing registry that started in 2010 and enrolled patients scheduled for an invasive coronary angiography due to suspected chronic coronary syndrome. Data of the following study patients were analysed: enrolment within the first two study years with available long-term follow-up data on the outcome measure overall mortality, availability of an ECG at admission without pacemaker stimulation and availability of all variables needed to calculate the ESC-SCORE (in the version weighed for a German population) as comparison. This led to a cohort of 720 patients, of whom 70 died within the follow-up period. Information on presence of a relevant coronary artery disease (CAD) was available for all patients, to differentiate between primary and secondary prevention. A deep learning architecture that was previously developed to detect myocardial scar in raw ECG time-series data was used. This model was trained with 1400 ECG recordings, from the publicly available PTB-XL dataset with 700 of those ECGs labelled for acute, recent or old myocardial infarction while 700 were labelled as healthy. This pre-trained model was then applied to our study cohort to predict long-term mortality based on a single 12-lead ECG obtained at admission.

Results

For mortality prediction in patients without CAD (primary prevention) the AI model compares to the ESC-SCORE with an AUROC of 0.606 vs 0.584. For CAD patients (secondary prevention) the AI model compares with an AUROC of 0.612 vs 0.658. Detailed results are presented in Table 1.

Conclusion(s)

Our data underlines the potential of an AI based approach, predicting mortality in cardiovascular patients using only single 12-lead ECG recordings. Additionally, our model achieved similar predictive information to established risk classification systems, such as the ESC-SCORE. Since data acquisition is still ongoing, we will continue to improve our model. In future work training AI to specifically predict mortality while also exploring explainable AI could lead to breakthrough findings in ECG interpretation.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): FlexiFunds by Forschungscampus Mittelhessen

Detecting a broader spectrum of cardiac pathologies in electrocardiogram data by applying a deep neural network designed to detect a specific cardiac disease

Background/Introduction

The electrocardiogram (ECG) is a widely used and inexpensive tool that provides extensive insights into the cardiac structure and function. Artificial intelligence (AI) algorithms, especially deep learning (DL) models, are efficient computer based instruments with which large and complex datasets can be processed for identification of e.g. specific diseases. PhysioNet is a NIH research resource for complex signals including a large amount of labelled ECG time-series data. Our aim was to evaluate the diagnostic performance of an AI architecture developed to detect a specific cardiac pathology in a large ECG data set including a broad range of cardiac abnormalities.

Methods

The PhysioNet ECG dataset provided as part of the PhysioNet Challenge 2020 consists of five distinct databases with a total of 43100 12-Lead ECG recordings of varying length stemming from patients from China, Russia, Europe and the United States. Each ECG recording is annotated with diagnoses based on a set of 111 possible labels, which express either a cardiac pathology, e.g. atrial flutter or anterior wall ischemia, or unspecific changes in the ECG, e.g. a prolonged qt interval or low qrs voltages. Based on these labels we defined 10 groups merging PhysioNet labels describing related cardiac abnormalities (see Table 1). We adapted a recently published DL model which used raw ECG time-series data of all 12-leads rather than extracted features as model input. This DL model was adapted to the larger number of output variables and then trained on 80% (n=34480 ECGs) of the PhysioNet dataset. The remaining 20% (n=8620 ECGs) of the PhysioNet dataset were used to evaluate the diagnostic performance of the AI model. Sensitivities, specificities and the areas under the receiver operator characteristic curves (AUROC) were used as performance metrices.

Results

The AI model, that was initially designed to detect a specific cardiac pathology, performed well in the large PhysioNet dataset providing AUROCs ranging from 0.78 to 0.95 to detect the defined 10 cardiac abnormality groups. Interestingly, the AI model was able to detect disease groups with changes in the chronological sequence of the ECG, e.g. arrhythmia, with comparable precision as disease groups associated primarily with changes in the ECG amplitude like e.g. ischemia. Detailed results are presented in Table 2.

Conclusion(s)

Our evaluation shows that an AI model that uses raw ECG time-series data rather than extracted features as model input can be easily transferred to other large datasets with different prediction variables. This might also serve as a proof of concept that raw data instead of pre-selected features should be used as model input if developing AI applications for medical use cases.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): FlexiFunds by Forschungscampus Mittelhessen

Investigating the Association of Wallerian Degeneration and Diaschisis After Ischemic Stroke With BOLD Cerebrovascular Reactivity

Introduction

Wallerian degeneration and diaschisis are considered separate remote entities following ischemic stroke. They may, however, share common neurophysiological denominators, since they are both related to disruption of fiber tracts and brain atrophy over time. Therefore, with advanced multimodal neuroimaging, we investigate Wallerian degeneration and its association with diaschisis.

Methods

In order to determine different characteristics of Wallerian degeneration, we conducted examinations on seventeen patients with chronic unilateral ischemic stroke and persisting large vessel occlusion, conducting high-resolution anatomical magnetic resonance imaging (MRI) and blood oxygenation-level dependent cerebrovascular reactivity (BOLD-CVR) tests, as well as Diamox ¹⁵(O)–H₂O–PET hemodynamic examinations. Wallerian degeneration was determined using a cerebral peduncle asymmetry index (% difference of volume of ipsilateral and contralateral cerebral peduncle) of more than two standard deviations away from the average of age-matched, healthy subjects (Here a cerebral peduncle asymmetry index > 11%). Diaschisis was derived from BOLD-CVR to assess the presence of ipsilateral thalamus diaschisis and/or crossed cerebellar diaschisis.

Results

Wallerian degeneration, found in 8 (47%) subjects, had a strong association with ipsilateral thalamic volume reduction (r² = 0.60) and corticospinal-tract involvement of stroke (p < 0.001). It was also associated with ipsilateral thalamic diaschisis (p = 0.021), No cerebral peduncular hemodynamic differences were found in patients with Wallerian degeneration. In particular, no CBF decrease or BOLD-CVR impairment was found.

Conclusion

We show a strong association between Wallerian degeneration and ipsilateral thalamic diaschisis, indicating a structural pathophysiological relationship.

Predictors for affected stroke territory and outcome of acute stroke treatments are different for posterior versus anterior circulation stroke

Distinct patient characteristics have been proposed for ischaemic stroke in the anterior versus posterior circulation. However, data on functional outcome according to stroke territory in patients with acute stroke treatment are conflicting and information on outcome predictors is scarce. In this retrospective study, we analysed functional outcome in 517 patients with stroke and thrombolysis and/or thrombectomy treated at the University Hospital Zurich. We compared clinical factors and performed multivariate logistic regression analyses investigating the effect of outcome predictors according to stroke territory. Of the 517 patients included, 80 (15.5%) suffered a posterior circulation stroke (PCS). PCS patients were less often female (32.5% vs. 45.5%, p = 0.031), received thrombectomy less often (28.7% vs. 48.3%, p = 0.001), and had lower median admission NIHSS scores (5 vs. 10, p < 0.001) as well as a better median three months functional outcome (mRS 1 vs. 2, p = 0.010). Predictors for functional outcome were admission NIHSS (OR 0.864, 95% CI 0.790–0.944, p = 0.001) in PCS and age (OR 0.952, 95% CI 0.935–0.970, p < 0.001), known symptom onset (OR 1.869, 95% CI 1.111–3.144, p = 0.018) and admission NIHSS (OR 0.840, 95% CI 0.806–0.876, p < 0.001) in ACS. Acutely treated PCS and ACS patients differed in their baseline and treatment characteristics. We identified specific functional outcome predictors of thrombolysis and/or thrombectomy success for each stroke territory.

Embolization of tumor cells is rare in patients with systemic cancer and cerebral large vessel occlusion

BACKGROUND AND PURPOSE

Stroke is a dreaded complication in patients with cancer. Besides paraneoplastic coagulopathy, chemotherapy, radiotherapy and tumor-directed invasive procedures, circulating cancer cells may contribute to thrombus formation and embolic stroke. However, the incidence of tumor cells within the blood clots of cancer patients with stroke is unknown and the role of circulating tumor cells in the formation of cerebrovascular thrombi remains unclear.

METHODS

All patients who had undergone cerebrovascular thrombectomy at the University Hospital Zurich between 2014 and 2017 were screened for history of cancer. Clinical information was retrieved from the local stroke registry and the electronic charts and thrombi underwent a thorough histopathological re-review.

RESULTS

Thirty-two of 182 patients (18%) with thrombectomy had a history of cancer. The majority of patients had advanced stage cancer. However, even after extensive histopathological re-review, only one specimen revealed tumor cells in the thrombus: a 75-year-old patient with acute occlusion of the middle cerebral artery who had been diagnosed with non-small-cell lung cancer 8.1 months prior to stroke.

CONCLUSIONS

The presence of cancer cells in clots from cerebrovascular thrombectomy, indicative of a direct involvement of circulating tumor cells in the causation of stroke, is rare.

Task-Specific Motor Rehabilitation Therapy After Stroke Improves Performance in a Different Motor Task: Translational Evidence

While the stroke survivor with a motor deficit strives for recovery of all aspects of daily life movements, neurorehabilitation training is often task specific and does not generalize to movements other than the ones trained. In rodent models of post-stroke recovery, this problem is poorly investigated as the training task is often the same as the one that measures motor function. The present study investigated whether motor training by pellet reaching translates into enhancement of different motor functions in rats after stroke. Adult rats were subjected to 60-min middle cerebral artery occlusion (MCAO). Five days after stroke, animals received either training consisting of 7 days of pellet reaching with the affected forelimb (n = 18) or no training (n = 18). Sensorimotor deficits were assessed using the sticky tape test and a composite neuroscore. Infarct volumes were measured by T2-weighted MRI on day 28. Both groups of rats showed similar lesion volume and forelimb impairment after stroke. Trained animals improved in the sticky tape test after day 7 post-stroke reaching peak performance on day 14. More reaching attempts during rehabilitation were associated with a better performance in the sticky tape removal time. Task-oriented motor training generalizes to other motor functions after experimental stroke. Training intensity correlates with recovery.

[Cognitive deficits and dementia in patients with multiple sclerosis: status quo and open questions]

Multiple sclerosis (MS) is the most common chronic immune-mediated disease which goes along with serious somatic and psychic symptoms. Whereas recent research rather focussed on the neurological symptoms of MS, there is nowadays an increasing interest among researchers in psychological symptoms of the disease. It is known that about half of the MS patients suffer from cognitive deficits, and that cognitive decline has a disadvantageous impact on lifestyle and quality of life in affected persons. So far, cognitive deficits in subjects with MS have been described as rather isolated, specific cognitive disturbances with otherwise intact intellectual abilities, while global deterioration of mental skills in terms of dementia is considered as being rather rare. In the present article, we describe cognitive domains which are typically impaired in subjects with MS and reflect on the question if the diagnosis of dementia might be underrepresented in MS patients due to several reasons (e.g., progression of cognitive deficits in the course of the disorder, adhering very closely to memory deficits as cardinal symptom of dementia, lack of longitudinal studies of cognitive performance levels). Furthermore, we recommend a multistage neuropsychological diagnostic procedure for clinical practice which aims at diagnosing cognitive deficits already in early stages of the illness. In so doing, practitioners may be able to offer adequate therapies to affected persons in all stages of the disorder in order to improve psychosocial functional levels.

U-HO1, a new cell line derived from a primary refractory classical Hodgkin lymphoma

The Hodgkin cell line U-HO1 was established from a malignant pleural effusion of a 23-year-old male patient during the end stage of refractory nodular sclerosing classical Hodgkin lymphoma (cHL). Since its establishment in 2005, U-HO1 has maintained stable characteristics in vitro and has a doubling time of about 4 days under standard culture conditions. U-HO1 forms typical Reed-Sternberg cells in suspension, is EBV negative, lacks HLA-A, -B, -C but expresses HLA-D proteins/CD74 and exposes CD15 together with CD30 in the absence of CD19 and CD20 on the cell surface. Karyotype analysis of U-HO1 revealed a hyperdiploid karyotype with multiple clonal aberrations. Most significant is an elongated chromosome 2, der(2)t(2;10)(q35; q16.1)add(2)(p13). CGH analysis revealed the following imbalances: ish cgh dim(1)(p13p31)(p12q21), enh(2)(p13p23), dim(4)(q31.3qter), enh(6)(q22q27), enh(12), enh(18), enh(20) (q13.1pter). FISH analysis showed about six-fold amplification of REL and BCL11A, thus, U-HO1 is prototypical for cHL in every aspect tested so far. As an outstanding feature compared to the existing HL cell lines, U-HO1 has high levels of microRNA transcripts of MIRN216 and MIRN217 located in the amplicon 2p16. Compared to other HL cell lines, U-HO1 proved far less genetically aberrant suggesting that U-HO1's imbalances suffice to cause the full-blown phenotype of primary refractory cHL.

Von Igeln auf Menschen

The hedgehog is an in Germany previously unrecognized source of human ringworm. Eight hedgehog caretakers from Göttingen and the surrounding area developed dermatophytosis caused by Trichophyton erinacei. Four patients who handled the animals without gloves developed lesions on the hands that were more in keeping with hand eczema, leading to a delay in diagnosis. The other caretakers who wore gloves presented with typical ringworm on the arms, the big toe, the back, the abdomen, and the thighs. Their typical clinical features led to an early diagnosis and treatment.

Mutations of the tumor suppressor gene SOCS-1 in classical Hodgkin lymphoma are frequent and associated with nuclear phospho-STAT5 accumulation

The suppressors of cytokine signaling (SOCS) are critically involved in the regulation of cellular proliferation, survival, and apoptosis via cytokine-induced JAK/STAT signaling. SOCS-1 silencing by aberrant DNA methylation contributes to oncogenesis in various B-cell neoplasias and carcinomas. Recently, we showed an alternative loss of SOCS-1 function due to deleterious SOCS-1 mutations in a major subset of primary mediastinal B-cell lymphoma (PMBL) and in the PMBL line MedB-1, and a biallelic SOCS-1 deletion in PMBL line Karpas1106P. For both cell lines our previous data demonstrated retarded JAK2 degradation and sustained phospho-JAK2 action leading to enhanced DNA binding of phospho-STAT5. Here, we analysed SOCS-1 in laser-microdissected Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL). We detected SOCS-1 mutations in HRS cells of eight of 19 cHL samples and in three of five Hodgkin lymphoma (HL)-derived cell lines by sequencing analysis. Moreover, we found a significant association between mutated SOCS-1 of isolated HRS cells and nuclear phospho-STAT5 accumulation in HRS cells of cHL tumor tissue (P < 0.01). Collectively, these findings support the concept that PMBL and cHL share many overlapping features, and that defective tumor suppressor gene SOCS-1 triggers an oncogenic pathway operative in both lymphomas.

[Mutations of the tumor suppressor gene SOCS-1 in classical Hodgkin lymphoma are frequent and associated with nuclear phospho-STAT5 accumulation]

AIMS

Suppressors of cytokine signaling (SOCS) negatively regulate Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling involved in proliferation, survival, and apoptosis. We previously showed a loss of SOCS-1 function due to deleterious mutations in a major subset of mediastinal B-cell lymphoma (MBL). In MBL cell lines this leads to retarded JAK2 degradation and sustained phospho-STAT5 action results in enhanced DNA binding of phospho-STAT5.

METHODS

To investigate the SOCS-1 gene we laser-microdissected Hodgkin-and Reed-Sternberg (HRS) cells of 19 classical Hodgkin lymphoma (cHL) and performed sequencing analysis. To assess phospho-STAT5 status immunohistochemistry on the corresponding paraffin-embedded cHL tumor tissue was done.

RESULTS

We detected mutations of the SOCS-1 gene in HRS cells of 8 of 19 cHL samples and in 3 of 5 cHL-derived cell lines. Moreover, we found a significant association between mutated SOCS-1 of isolated HRS cells and nuclear phospho-STAT5 accumulation in HRS cells (P <0.01).

CONCLUSIONS

In conclusion, these findings support the concept that MBL and cHL share overlapping features and that defective tumor suppressor gene SOCS-1 triggers an oncogenic pathway operative in both lymphomas.

[Biallelic mutation of SOCS-1 impairs JAK2 degradation and sustains phospho-JAK2 action in MedB-1 mediastinal lymphoma line]

Primary mediastinal B-cell lymphoma (PMBL) is a well-defined subtype of diffuse large B-cell lymphoma. Molecular cytogenetics revealed frequent gains of 9 p24. JAK2, mapping in this region, is presently regarded as a candidate oncogene since expression profiling showed high JAK2 transcript levels and JAK2 was found to be constitutively phosphorylated in mediastinal B-cell lymphomas. We confirm that in the MedB-1 mediastinal B-cell line, harbouring a trisomy 9, JAK2 transcription is elevated and the product is highly phosphorylated. However, JAK2 is not over-expressed at the protein level. On top, JAK2 protein turnover is even delayed. This unexpected finding coincides with a biallelic mutation of the SOCS-1 gene in this cell, which abrogates SOCS box function of the protein. Ectopic expression of wt-SOCS-1 in MedB-1 leads to growth arrest, dramatic reduction of phospho-JAK2 and its downstream partner phospho-STAT5. We conclude that, in MedB-1, action of phospho-JAK2 is sustained due to defective SOCS-1. Hence, SOCS-1 qualifies as a novel tumor suppressor. Of note, the SOCS-1 mutations are also present in the parental tumor of MedB-1 and were detected in 9 of 20 PMBL.

Sulfonylurea drugs do not influence initial stroke severity and in-hospital outcome in stroke patients with diabetes

BACKGROUND AND PURPOSE

Sulfonylurea drugs inhibit ATP-dependent potassium channels and may increase mortality after myocardial infarction. Sulfonylurea drugs also inhibit ischemic preconditioning in experimental models of brain ischemia and in clinical studies in the human heart.

METHODS

In the present study we examined the impact of sulfonylurea drugs on in-hospital mortality and the immediate neurological deficit of diabetic stroke patients. From a larger stroke data bank, we studied 146 diabetic patients with acute hemispheric ischemic stroke. Sixty patients were using sulfonylurea drugs.

RESULTS

Major baseline characteristics such as age, blood pressure, admission glucose level, HbA(1c), distribution of cardiovascular risk factors, and presumed stroke etiology (Trial of Org 10172 in Acute Stroke Treatment [TOAST] criteria) were not different. Mortality (15% versus 14%; P=0.86) and initial stroke severity (Canadian Neurological Scale score, 7.4 versus 7.5; P=0.79) were not significantly different between patients with and without sulfonylurea drugs. Further end points such as Rankin Scale score, deteriorating stroke, duration of hospital stay, type of infarcts on CT/MRI, requirement of intensive care, and complications were not different. In a stepwise logistic regression model, sulfonylurea drugs were not independent predictors for increased mortality, deteriorating stroke, or stroke severity.

CONCLUSIONS

In the present hospital-based study, sulfonylurea drugs in patients with diabetes and stroke are not associated with increased stroke severity, mortality, or a worse in-hospital outcome.

A gene related to yeast HOS2 histone deacetylase affects extracellular depolymerase expression and virulence in a plant pathogenic fungus

A gene, HDC1, related to the Saccharomyces cerevisiae histone deacetylase (HDAC) gene HOS2, was isolated from the filamentous fungus Cochliobolus carbonum, a pathogen of maize that makes the HDAC inhibitor HC-toxin. Engineered mutants of HDC1 had smaller and less septate conidia and exhibited an approximately 50% reduction in total HDAC activity. Mutants were strongly reduced in virulence as a result of reduced penetration efficiency. Growth of hdc1 mutants in vitro was normal on glucose, slightly decreased on sucrose, and reduced by 30 to 73% on other simple and complex carbohydrates. Extracellular depolymerase activities and expression of the corresponding genes were downregulated in hdc1 mutant strains. Except for altered conidial morphology, the phenotypes of hdc1 mutants were similar to those of C. carbonum strains mutated in ccSNF1 encoding a protein kinase necessary for expression of glucose-repressed genes. These results show that HDC1 has multiple functions in a filamentous fungus and is required for full virulence of C. carbonum on maize.

Penicillin-resistant streptococcus pneumoniae: review of moxifloxacin activity

Streptococcus pneumoniae is a significant pathogen of respiratory tract infections such as pneumonia, sinusitis, meningitis, and acute otitis media. Rising incidences of antimicrobial resistance among pneumococcal strains reported worldwide have led to research into and development of advanced antibacterials with improved gram-positive activity. Moxifloxacin, a new 8-methoxy quinolone, has been tested against a variety of S. pneumoniae strains, including penicillin-sensitive, intermediately resistant to penicillin, and penicillin-resistant strains. We review the preclinical data corroborated by the available clinical experience to demonstrate moxifloxacin's activity against S. pneumoniae strains, irrespective of penicillin susceptibility.

Alternative splicing in the regulatory region of the human phosphatases CDC25A and CDC25C

CDC25 phosphatases play key roles in cell proliferation by activating cell cycle-specific cyclin-dependent kinases (CDKs). We identified four new splice variants in the amino-terminal regulatory region of human cdc25C and one in cdc25A. All variants except one retain an intact catalytic domain. Alternative splicing results in loss of phosphorylation sites for kinases like CDK and the calcium/calmodulin-dependent kinase II (CaMKII), which influence CDC25 activity and compartmental localization. In NT2 teratocarcinoma cells, induced for nerve cell differentiation, the smaller sized variant of cdc25C was upregulated. At the protein level both phosphorylation state and isoform distribution differed between cell lines and cell cycle phases.

RPD3-type histone deacetylases in maize embryos

Posttranslational core histone acetylation is established and maintained by histone acetyltransferases and deacetylases. Both have been identified as important transcriptional regulators in various eukaryotic systems. In contrast to nonplant systems where only RPD3-related histone deacetylases (HD) have been characterized so far, maize embryos contain three unrelated families of deacetylases (HD1A, HD1B, and HD2). Purification, cDNA cloning, and immunological studies identified the two maize histone deacetylase HD1B forms as close homologues of the RPD3-type deacetylase HDAC1. Unlike the other maize deacetylases, HD1A and nucleolar HD2, HD1B copurified as a complex with a protein related to the retinoblastoma-associated protein, Rbap46. Two HD1B mRNA species could be detected on RNA blots, encoding proteins of 58 kDa (HD1B-I) and 51 kDa (HD1B-II). HD1B-I (zmRpd3) represents the major enzyme form as judged from RNA and immunoblots. Levels of expression of HD1B-I and -II mRNA differ during early embryo germination; HD1B-I mRNA and protein are present during the entire germination pathway, even in the quiescent embryo, whereas HD1B-II expression starts when meristematic cells enter S-phase of the cell cycle. In line with previous results, HD1B exists as soluble and chromatin-bound enzyme forms. In vivo treatment of meristematic tissue with the deacetylase inhibitor HC toxin does not affect the expression of the three maize histone deacetylases, whereas it causes downregulation of histone acetyltransferase B.

Genomic sequence and mapping of a methyljasmonate-induced O-methyltransferase from barley (Hordeum vulgare L.)

We have isolated a genomic clone corresponding to a caffeic acid O-methyltransferase (COMT) from barley (Hordeum vulgare L.) using a cDNA for a previously described jasmonate-regulated mRNA showing homology to COMT. Primer extension was used to characterize the 5' end of the mRNA while the 3' end, intron/exon structure and other features of the sequence were deduced by comparison to the cDNA sequence and/or conserved motifs. The gene is mapped to chromosome five and is absent in the barley cultivar Morex. Southern and northern analyses suggest that no differences in genomic structure and jasmonate inducibility exist between the barley cultivar Salome (source of the cDNA clone) and Igri (source of the genomic clone). This genomic clone is thus suitable for promoter studies with respect to jasmonate induction.

[Protein A immunoadsorption al a new apheresis procedure for elimination of HLA antibodies]

The protein A immunoadsorption allows to remove antibodies of the classes IgG, IgM and IgA in special quantities from the plasma. IgG subclasses 1, 2 and 4 will be removed for 100% and IgG of class 3 for nearly 80%. For this reason immunoadsorptions are a useful therapeutic method especially for immunological diseases with antibodies of IgG type. The successful use of immunoadsorption in the removal of HLA antibodies in patients with acute myeloic leukemia and patients after kidney allograft is reported.

Quantitation of soluble HLA-DR antigens in human serum and other body fluids

The existence of soluble forms of MHC class II molecules is well established. To quantify soluble HLA-DR antigens (sHLA-DR) in human serum and other body fluids, we developed an enzyme immunoassay using two non-overlapping HLA-DR-specific monoclonal antibodies (RoDR, BL-la/5) and an immunoaffinity chromatography-purified sHLA-DR standard. In serum of healthy individuals, sHLA-DR levels were found in the range between 0.6 and 3 ng/ml (median 0.85 ng/ml) whereas EDTA plasma samples showed concentrations about 20 times higher (median 21 ng/ml). In tears, saliva, sweat, urine, amniotic fluid, cerebrospinal fluid, and bronchoalveolar lavage, sHLA-DR could also be detected. No association was found between sHLA-DR serum levels and distinct HLA specificities. In the sera of patients with autoimmune diseases, slightly enhanced sHLA-DR values were found (juvenile rheumatoid arthritis: median 2.0 ng/ml, lupus erythematosus: 1.5 ng/ml, diabetes mellitus: 2.1 ng/ml).

[Inline filtration of erythrocyte concentrates with the Leucoflex LCR4 T/B system]

The in-line-filtration of red cell concentrates (RCC) is an effective method to reduce white-cell-induced reactions. SAG-M RCCs were prepared in quadruple top/bottom bag systems and filtered after storage at 4 degrees C (study: n = 12). The mean white blood cell (WBC) reduction was 99.9% with the number of residual WBCs at about 0.67 x 10(6) per unit and with a loss of Hb mass of 10.64%. No cell fragments of WBCs and monocytes were detected (MAIPA). After storage of 42 days, mean values of hemolysis level (0.64%) and ATP concentration (2.27 mumol/g Hb) were improved compared with unfiltered RCCs. Comparably good results of leukocyte depletion were achieved by preparation of about 3,000 in-line filtrated RCCs for clinical use, measured by routine quality control (n = 25). Our experience shows that the systems are easy to handle and to use. The Leucoflex LCR4 in-line T/B system (Maco Pharma) can be recommended in the clinical practice by virtue of the effective leukocyte elimination, particularly in those blood banks with platelet concentrate production from buffy coats beside the RCC in-line filtration.

A muscarinic acetylcholine receptor, present in the epithelial cell line from Chironomus tentans

A muscarinic cholinergic receptor (mAchR) is present in the non-neuronal epithelial cell line from Chironomus tentans. Scatchard plot analysis (KD = 1.4 nM) using the non-selective antagonist quinuclidinylbenzilate (QNB), as well as kinetic data (KD = 1.7 nM), reveals one class of high affinity binding sites. About 2000 binding sites/cell are present. The receptor concentration (54.5 +/- 7.5 fmol/mg protein) is comparable to the values reported from insect brain. The receptor interacts only with muscarinic ligands; nicotinergic acetylcholine receptors are not present. Binding properties are not comparable to any of the muscarinic subtypes known from vertebrate tissues. The rank order of competition of radiolabelled QNB is: QNB > atropine > PrBCM > oxotremorine, pirenzepine > methoctramine. The competition curve obtained with carbamylcholine is shifted to higher ligand concentrations in the presence of Gpp(NH)p and to lower carbamylcholine concentrations by 1 mM NEM. With antibodies against muscarinic receptor from calf brain one band with a molecular weight of about 80 kDa is detected on Western blots. The moulting hormone 20-OH-ecdysone transiently increases the concentration of muscarinic receptor.

Influence of anticoagulants on the level of soluble HLA class I and class II antigens measured in blood samples

The existence of soluble forms of HLA class I and class II antigens in human serum is well established and altered concentrations of these serum proteins have been described to be associated with various diseases. Since soluble HLA antigens (sHLA) can be measured both in serum and plasma samples, we investigated whether anticoagulant treatment influences the determined levels of soluble HLA class I (sHLA-I) or soluble HLA-DR (sHLA-DR). Analyzing paired samples of serum and plasma of 40 healthy individuals we found significantly lower serum levels of sHLA-DR (0.31 +/- 0.15 ng/ml) compared to EDTA plasma levels (0.58 +/- 0.20 ng/ml). By contrast, serum levels of sHLA-I (0.89 +/- 0.74 micrograms/ml) were only slightly lower than EDTA plasma values (0.95 +/- 0.86 micrograms/ml), a situation similar to that of sIL-2R and sCD4 levels. Further experiments intended to clarify the reasons of the reduced sHLA-DR serum levels revealed that (i) the blood storage time before centrifugation did not influence the sHLA-DR level, (ii) treatment of serum with anticoagulant did not augment the measured sHLA-DR concentration, and (iii) the recovery of spiked sHLA-DR was significantly lower when added to native blood than to serum or anticoagulant-treated blood. These results suggest that sHLA-DR is partly removed by the process of blood clotting thus resulting in diminished sHLA-DR serum levels.