Efficient formation and maintenance of humoral and CD4 T-cell immunity targeting the viral capsid in acute-resolving hepatitis E infection

BACKGROUND & AIMS

CD4 T cells shape the neutralizing antibody (nAb) response and facilitate viral clearance in various infections. Knowledge of their phenotype, specificity and dynamics in hepatitis E virus (HEV) infection is limited. HEV is enterically transmitted as a naked virus (nHEV) but acquires a host-derived quasi-envelope (eHEV) when budding from cells. While nHEV is composed of the open reading frame (ORF)-2-derived capsid, eHEV particles also contain ORF3-derived proteins. We aimed to longitudinally characterize the HEV-specific CD4 T cells targeting ORF1, 2 and 3 and antibodies against nHEV or eHEV in immunocompetent individuals with acute and resolved HEV infection.

METHODS

HEV-specific CD4 T cells were analyzed by intracellular cytokine staining after stimulation with in silico-predicted ORF1- and ORF2-derived epitopes and overlapping peptides spanning the ORF3 region. Ex vivo multiparametric characterization of capsid-specific CD4 T cells was performed using customized MHC class II tetramers. Total and neutralizing antibodies targeting nHEV or eHEV particles were determined.

RESULTS

HEV-specific CD4 T-cell frequencies and antibody titers are highest in individuals with acute infection and decline in a time-dependent process with an antigen hierarchy. HEV-specific CD4 T cells strongly target the ORF2-derived capsid and ORF3-specific CD4 T cells are hardly detectable. NAbs targeting nHEV are found in high titers while eHEV particles are less efficiently neutralized. Capsid-specific CD4 T cells undergo memory formation and stepwise contraction, accompanied by dynamic phenotypical and transcriptional changes over time.

CONCLUSION

The viral capsid is the main target of HEV-specific CD4 T cells and antibodies in acute-resolving infection, correlating with efficient neutralization of nHEV. Capsid-specific immunity rapidly emerges followed by a stepwise contraction several years after infection.

IMPACT AND IMPLICATIONS

The interplay of CD4 T cells and neutralizing antibody responses is critical in the host defense against viral infections, yet little is known about their characteristics in hepatitis E virus (HEV) infection. We conducted a longitudinal study of immunocompetent individuals with acute and resolved HEV infection to understand the characteristics of HEV-specific CD4 T cells and neutralizing antibodies targeting different viral proteins and particles. We found that HEV-specific CD4 T cells mainly target capsid-derived epitopes. This correlates with efficient neutralization of naked virions while quasi-enveloped particles are less susceptible to neutralization. As individuals with pre-existing liver disease and immunocompromised individuals are at risk for fulminant or chronic courses of HEV infection, these individuals might benefit from the development of vaccination strategies which require a detailed knowledge of the composition and longevity of HEV-specific CD4 T-cell and antibody immunity.

Behavioural responses of beef cattle to different grazing systems and the influence of these responses on water productivity of livestock in a tropical savannah

Environmental conditions and available forage on pastures greatly differ between different farming systems, which can affect the behaviour of grazing cattle. The interplay between environment-, forage-, and animal-related variables may affect the use of feed and water resources in grazing-based systems. Hence, our objectives were (i) to study the differences between grazing-based systems and seasons in environment- and pasture-related variables as well as the behaviour, feed intake, performance, and water productivity of Nellore heifers, and (ii) to understand the interrelationships between these variables. The measurements were performed in a conventional grazing system (CON), an integrated crop-livestock (ICL), and a crop-livestock-forestry (ICLF) systems in the Brazilian Cerrado during the rainy and dry seasons. Ambient temperature and relative air humidity were hourly measured in both seasons. Forage biomass and sward height were determined every month. Forage samples were taken to determine the proportions of alive leaves, alive stems, and dead plant material and to analyse their nutritive value. Forage intake, drinking water intake, and liveweight changes were quantified in 12 Nellore heifers per system and season. Feeding behaviour was recorded by chewing sensors on nine continuous days in each season. Drinking water intake was measured by water meters attached to drinking water troughs, whereby trial cameras at the troughs recorded the frequency of drinking events of individual animals. Feed conversion efficiency and water productivity were estimated. The ICLF reduced the exposure time to high ambient temperatures so that heifers even grazed during the hottest hours. Forage biomass in ICL and CON had greater proportions of stem and dead plant material than in ICLF. Forage intake rate was greater and grazing events were longer for animals in ICLF than those in CON, whereas the daily number of grazing events was greater in CON. Feed conversion efficiency and water productivity were greater in integrated systems than in CON. Amongst studied variables, thermal environment and forage canopy structure with its proportions of dead plant material are the main driving factors for animal behaviour, forage intake rate, and animal performance. These variables reduce feed conversion efficiency and water productivity in grazing cattle. Further research should analyse strategies for promoting thermal comfort for the animals, increasing the proportions of alive biomass, and enhancing the nutritional value of pastures for more efficient use of forage and water resources in grazing-based systems.

In-vitro model to mimic T cell subset change in human PDAC organoid co-culture

PURPOSE

Immunotherapies have largely failed as treatment options for pancreatic ductal adenocarcinoma (PDAC). In this field, clinical translational studies into personalized treatment are of fundamental importance. In our study, we model tumor-cell immune-cell interactions in a co-culture of primary human PDAC organoids and matched peripheral blood mononuclear cells (PBMCs).

METHODS

Using flow cytometry, we evaluated changes in T cell subtypes upon co-culture of patient-derived PDAC organoids and matched PBMCs.

RESULTS

After co-culturing PDAC organoids with PBMCs, we observed changes in CD4+, CD8+ and Treg cell populations. We observed favorable clinical outcome in patients whose PBMCs reacted to the co-culture with organoids.

CONCLUSION

This experimental model allows to investigate interactions between patient derived PDAC organoids and their PBMCs. This co-culture system could serve as a preclinical platform to guide personalized therapeutic strategies in the future.

Advances in rectal cancer: Real-world evidence suggests limited gains in prognosis for elderly patients

BACKGROUND

Rectal cancer treatment has improved considerably due to the introduction of total meso-rectal excision, radio-chemotherapy, and high-resolution imaging. The aim of this observational cohort study was to quantify the effectiveness of these advances using high-quality data from a representative cohort of patients.

METHODS

20 281 non-metastasized cases retrieved from the Munich Cancer Registry database were divided into three time periods corresponding to before (1988-1997), partial (1998-2007), and full implementation (2008-2019) of clinical advances. Early-onset (<50 yrs.), middle-aged, elderly patient subgroups (> 70 yrs.) were compared. The overall effectiveness of evidence-based guideline adherence was also examined.

RESULTS

Median survival improved by 1.5 yrs. from the first to the last time period. Relative survival increased from 74.9% (5-yr 95%CI[73.3 - 76.6]) to 79.2% (95%CI[77.8 - 80.5]). The incidence of locoregional recurrences was reduced dramatically by more than half (5-yr 17.7% (95%CI[16.5 - 18.8]); 6.7% (95%CI[6.1 - 7.3])). Gains in 5-yr relative survival were limited to early-onset and middle-aged patients with no significant improvement seen in elderly patients (Female 68.6% [63.9 - 73.3] to 67.6% [64.0 - 71.2]; Male 71.7% [65.9 - 77.4] to 74.0% [70.8 - 77.2]).

CONCLUSIONS

Real-world evidence suggests that recent treatment advances have lead to an increase in prognosis for rectal cancer patients. However, more effort should be made to improve the implementation of new developments in elderly patients. Especially considering, that these cases represent a growing majority of diagnosed patients.

[Treatment of pancreatic injuries after blunt abdominal trauma]

Pancreatic injuries resulting from blunt abdominal trauma are uncommon but carry a high risk of morbidity and mortality for patients. Prompt diagnosis and management are critical to optimize patient outcomes. This review article provides an overview of the different types of pancreatic injuries and the various management strategies available, based on the severity of the injury. In unstable patients with a positive focused assessment with sonography for trauma (FAST), immediate trauma laparotomy is required. Stable patients should be assessed with contrast-enhanced computed tomography (CT) imaging. Low-grade injuries can be managed with irrigation and drainage. In cases of left-sided ductal injury below the level of the portal vein, left-sided pancreatic resection is often necessary. Higher grade injuries to the pancreatic head need to be evaluated in the context of other accompanying injuries, where damage control may be required. Pancreaticoduodenectomy is a rare intervention and is usually only required in the later course in these cases.

On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslands

The objective of the present on-farm study was to evaluate the adequacy of existing models in predicting the pasture herbage DM intake (PDMI) of lactating dairy cows grazing semi-natural grasslands. The prediction adequacy of 13 empirical and semi-mechanistic models, which were predominantly developed to represent stall-fed cows or cows grazing high-quality pastures, were evaluated using the mean bias, relative prediction error (RPE), and partitioning of mean square error of prediction, where models with an RPE ≤ 20% were considered adequate. The reference dataset comprised n = 233 individual animal observations from nine commercial farms in South Germany with a mean milk production, DM intake, and PDMI (arithmetic means ± one SD) of 24 kg/d, (±5.6), 21 kg/d (±3.2), and 12 kg/d (±5.1), respectively. Despite their adaptation to grazing conditions, the behaviour-based and semi-mechanistic grazing-based models had the lowest prediction adequacy among the evaluated models. Their underlying empirical equations likely did not fit the grazing and production conditions of low-input farms using semi-natural grasslands for grazing. The semi-mechanistic stall-based model Mertens II with slight modifications achieved the highest and a satisfactory modelling performance (RPE = 13.4%) when evaluated based on the mean observed PDMI, i.e., averaged across animals per farm and period (n = 28). It also allowed for the adequate prediction of PDMI on individual cows (RPE = 18.5%) that were fed < 4.8 kg DM of supplement feed per day. Nevertheless, when used to predict PDMI of individual animals receiving a high supplementation level, the model Mertens II also did not meet the threshold for an acceptable adequacy (RPE = 24.7%). It was concluded that this lack of prediction adequacy for animals receiving greater levels of supplementation was due to a lack of modelling precision, which mainly could be related to inter-animal and methodological limitations such as the lack of individually measured supplement feed intake for some cows. The latter limitation is a trade-off of the on-farm research approach of the present study, which was chosen to represent the range in feed intake of dairy cows across the diverse low-input farming systems using semi-natural grasslands for grazing.

Stem and leaf xylem of angiosperm trees experiences minimal embolism in temperate forests during two consecutive summers with moderate drought

Drought events may increase the likelihood that the plant water transport system becomes interrupted by embolism. Yet our knowledge about the temporal frequency of xylem embolism in the field is frequently lacking, as it requires detailed, long-term measurements. We measured xylem embolism resistance and midday xylem water potentials during the consecutive summers of 2019 and 2020 to estimate maximum levels of embolism in leaf and stem xylem of ten temperate angiosperm tree species. We also studied vessel and pit membrane characteristics based on light and electron microscopy to corroborate potential differences in embolism resistance between leaves and stems. Apart from A. pseudoplatanus and Q. petraea, eight species experienced minimum xylem water potentials that were close to or below those required to initiate embolism. Water potentials corresponding to ca. 12% loss of hydraulic conductivity (PLC) could occur in six species, while considerable levels of embolism around 50% PLC were limited to B. pendula and C. avellana. There was a general agreement in embolism resistance between stems and leaves, with leaves being equally or more resistant than stems. Also, xylem embolism resistance was significantly correlated to intervessel pit membrane thickness (T_PM ) for stems, but not to vessel diameter and total intervessel pit membrane surface area of a vessel. Our data indicate that low amounts of embolism occur in most species during moderate summer drought, and that considerable levels of embolism are uncommon. Moreover, our experimental and T_PM data show that leaf xylem is generally no more vulnerable than stem xylem.

P11.53.B Efficacy and tolerability of regorafenib in pretreated patients with progressive CNS grade 3 or 4 gliomas

Background

The phase 2 REGOMA trial suggested an encouraging overall survival benefit in glioblastoma patients at first relapse treated with the multikinase inhibitor regorafenib. Here, we evaluated the efficacy and side effects of regorafenib in a real-life setting.

Material and Methods

From 2018-2021, 30 patients with progressive WHO CNS grade 3 or 4 gliomas treated with regorafenib (160 mg/d; first 3 weeks of each 4-week cycle) with individual dose adjustment depending on toxicity were retrospectively identified. Side effects were evaluated according to the Common Terminology Criteria for Adverse Events (version 5.0). MRI was obtained at baseline and after every second cycle. Tumor progression was assessed according to RANO criteria. After regorafenib initiation, the median progression-free survival (PFS) and overall survival (OS) were calculated.

Results

The median number of treatment lines before regorafenib was 2 (range, 1-4). The majority of patients (73%) had two or more pretreatment lines. At first relapse, 27% of patients received regorafenib. A total of 94 regorafenib cycles were administered (median number of cycles, 2; range, 1-9 cycles). Grade 3 and 4 side effects were observed in 47% and 7% of patients, respectively, and were not significantly increased in patients with two or more pretreatments (P&gt;0.05). The most frequent grade 3 or 4 side effects were laboratory abnormalities (62%). PFS was 2.6 months (range, 0.8-8.2 months), and the OS was 6.2 months (range, 0.9-24 months).

Conclusion

In patients with progressive WHO grade 3 or 4 gliomas, predominantly with two pretreatment lines or more, regorafenib seems to be effective despite considerable grade 3 or 4 side effects.

KS02.7.A Impact of FET PET on multidisciplinary neurooncological tumor board decisions in patients with brain tumors

Background

Following neurooncological treatment of brain tumors, neurooncologists are often confronted with equivocal MRI findings (e.g., treatment-related changes such as pseudoprogression, non-measurable contrast-enhancing lesions, T2/FLAIR signal alterations, pseudoresponse). Especially in Europe, amino-acid PET is increasingly integrated into multidisciplinary neurooncological tumor boards (MNTB) to overcome these diagnostic uncertainties. We evaluated the correctness of MNTB decisions, in which amino acid PET findings were taken into account.

Material and Methods

In a single-university center study, we retrospectively evaluated 182 MNTB decisions of 154 patients with histomolecularly defined WHO grade 3 or 4 gliomas (n=123), including glioblastoma (n=80), anaplastic glioma (n=42), and gliosarcoma (n=1), or brain metastases (n=31) secondary to lung cancer, melanoma, breast cancer, or colorectal cancer presenting equivocal MRI findings following anticancer treatment. All patients underwent O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET imaging as an adjunct for decision-making. Additionally, the patients’ clinical status, pretreatment, and conventional MRI findings were considered for decision-making. The presence of neoplastic tissue was considered if the mean FET uptake as assessed by tumor-to-brain ratios was &gt; 2.0. MNTB decisions were validated using the neuropathological result in 42% (n=77) or clinicoradiologically in 58% (n=105). The diagnostic performance of MTNB decisions was evaluated using 2x2 contingency tables.

Results

The validation of all 182 MNTB recommendations, which integrated FET PET in the decision-making process, were correct in 95% (sensitivity, 97%; specificity, 75%; positive predictive value, 96%). Due to tumor progression, MNTB recommendations prompted a treatment change in 88% (n=160 of 182 decisions). When FET PET findings suggested progressive disease (n=157), MNTB decisions were correct in 96% (positive predictive value, 97%). In 22 MNTB decisions with the recommendation to continue the current treatment regimen, 82% were correctly identified as treatment-related changes.

Conclusion

FET PET seems to have a significant impact on MNTB decisions. A prospective evaluation of MNTB decisions with and without the integration of FET PET is warranted to define the added value of FET PET.

P15.05.A Prediction of response to lomustine-based chemotherapy in glioma patients at relapse using MRI and FET PET

Background

This study evaluates O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET and contrast-enhanced MRI for early response assessment in glioma patients at relapse treated with lomustine-based chemotherapy.

Material and Methods

Thirty-seven adult patients with WHO CNS Grade 3 or 4 gliomas at relapse (glioblastoma, 70%; median number of relapses, 1) were retrospectively identified. Besides MRI, serial FET PET scans were performed at baseline and early after chemotherapy initiation (median number of cycles, 2). Mean and maximum tumor-to-brain ratios (TBR), metabolic tumor volumes (MTV), the occurrence of distant hotspots with a mean TBR &gt; 1.6 at follow-up, and dynamic parameters (i.e., time-to-peak and slope) were derived from all FET PET scans. Threshold values of PET parameters were defined using receiver operating characteristic analyses to predict progression-free survival (PFS) of ≥6 months and overall survival (OS) of ≥12 months. MRI response assessment was based on RANO criteria. The predictive value of FET PET parameters and RANO criteria were subsequently evaluated using univariate and multivariate survival estimates.

Results

After treatment initiation, the median follow-up time was 11 months (range, 3-71 months). Maximum TBR and MTV (threshold, ≤0%) and RANO criteria predicted a significantly longer PFS (all P&lt;0.001) and OS (all P&lt;0.03). At follow-up FET PET imaging, the occurrence of new distant hotspots (n≥1) predicted a worse outcome, with significantly shorter PFS (P=0.001) and OS (P&lt;0.001). Dynamic PET parameters did not predict a significantly longer PFS or OS (P&gt;0.05). Multivariate survival analyses revealed that new distant hotspots at follow-up had the highest level of significance to predict non-response (P=0.002; hazard ratio, 5.722), independent of RANO criteria, IDH mutation status, and O6-methylguanine-DNA-methyltransferase promoter methylation.

Conclusion

FET PET seems to be a powerful tool for identifying responders to lomustine-based chemotherapy early after treatment initiation.

Preservation of the round ligament to accommodate transient portal hypertension after major hepatectomy

Purpose

Posthepatectomy liver failure (PHLF) remains a leading cause of death after extensive liver resection. Apart from the size and function of the remaining liver remnant, the development of postresection portal hypertension (pHT) plays a crucial role in the development of PHLF. We hypothesize that the umbilical vein in the preserved round ligament (RL) may recanalize in response to new-onset pHT after extended hepatectomy, thus providing a natural portosystemic shunt.

Methods

In this exploratory study, RL was preserved in 10 consecutive patients undergoing major liver resection. Postoperative imaging was pursued to obtain evidence of reopened umbilical vein in the RL. The postoperative course, including the occurrence of PHLF, as well as the rate of procedure-specific complications were recorded.

Results

None of the 10 cases presented with an adverse event due to preservation of the RL. In 6 cases, postoperative imaging demonstrated reopening of the umbilical vein with hepatofugal flow in the RL. The rates of procedure-related surgical complications were lower than would be expected in this population; in particular, the rate of occurrence of PHLF as defined by the International Study Group of Liver Surgery (ISGLS) was low.

Conclusion

Our results support the theoretical concept of portosystemic pressure relief via a preserved umbilical vein after major liver surgery. As preservation of the RL is easily done, we suggest keeping it intact in extended hepatectomy cases and in patients with preexistent pHT.

0625 Characterization of Obstructive Sleep Apnea in Active-Duty US Military Personnel Receiving Interdisciplinary Care at the National Intrepid Center of Excellence

Introduction

Among active-duty service members (ADSMs), obstructive sleep apnea (OSA) is associated with decreased quality of life and military readiness/retention. Limited evidence suggests mild traumatic brain injury (mTBI) patients have increased OSA incidence, but little is known about the underlying physiology. This study aims to characterize OSA in treatment-seeking ADSMs with a history of remote mTBI and/or persistent neurobehavioral symptoms to improve detection and early intervention.

Methods

This is a retrospective analysis of data collected from ADSMs attending the National Intrepid Center of Excellence Intensive Outpatient Program for persistent symptoms associated with mTBI. Sleep assessment included overnight polysomnography and self-report assessments of sleep quality, somatic and mood symptoms. OSA severity was determined by apnea-hypopnea index (negative: &lt;5, mild: 5-15, moderate/severe: ≥15). Group differences were assessed using analysis of covariance and pairwise least squares regression, controlling for age and body mass index, and corrected for multiple comparisons.

Results

Analyses included 574 ADSMs, mostly male (99%), with a mean age of 39.7. The majority (n=288; 50.2%) were OSA negative (OSA-neg); a third had mild OSA (m-OSA) (n=216; 38%); and a tenth were diagnosed with moderate/severe OSA (mod/s-OSA) (n=70; 12%). Mod/s-OSA patients had increased arousal index (p&lt;0.01), hypoxia time (p&lt;0.001), reduced total sleep time (p&lt;0.01) and sleep efficiency (p&lt;0.001) compared to m-OSA and OSA-neg patients. M-OSA patients had an increased arousal index compared to OSA-neg patients (p&lt;0.01). Patient groups did not significantly differ on subjective measures of sleep (i.e., quality, sleepiness), post-concussive, or behavioral health symptoms (anxiety, depression, post-traumatic stress symptoms, alcohol misuse).

Conclusion

In our sample of treatment-seeking ADSMs, nearly half presented with OSA according to cut-scores derived for AHI, greater than that expected in the general population. As reported in civilian populations, mod/s-OSA patients demonstrated worse objective sleep measures compared to m-OSA and OSA-neg patients, yet in our sample their self-reported symptom severity did not differ. These findings suggest a low threshold for OSA screening is needed in the symptomatic mTBI population and that multiple factors other than OSA likely contribute to perceived sleep disturbances and neurobehavioral symptoms.

Support (If Any)

None.

Prognosis and tumor biology of pancreatic cancer patients with isolated lung metastases: translational results from the German multicenter AIO-YMO-PAK-0515 study

Background

Pulmonary metastasis (M1-PUL) as first site of dissemination in pancreatic ductal adenocarcinoma (PDAC) is a rare event and may define a distinct biological subgroup.

Patients and methods

Arbeitsgemeinschaft Internistische Onkologie-Young Medical Oncologists-Pankreas-0515 study (AIO-YMO-PAK-0515) was a retrospective German multicenter study investigating clinical and molecular characteristics of M1-PUL PDAC patients; 115 M1-PUL PDAC patients from 7 participating centers were included. Clinical characteristics and potential prognostic factors were defined within the M1-PUL cohort. Archival tumor samples were analyzed for Her2/neu, HNF1A and KRT81 expression. Additionally, messenger RNA (mRNA) expression analysis (using a 770-gene immune profiling panel) was carried out in the M1-PUL and in a control cohort (M1-ANY).

Results

Median overall survival in the entire M1-PUL cohort was 20 months; the most favorable prognosis (median survival: 28 months) was observed in the subgroup of 66 PDAC patients with metachronous lung metastases after previous curative-intent surgery. The number of metastatic lesions, uni- or bilateral lung involvement as well as metastasectomy were identified as potential prognostic factors. Her2/neu expression and PDAC subtyping (by HNF1A and KRT81) did not differ between the M1-PUL and the M1-ANY cohort. mRNA expression analysis revealed significant differentially expressed genes between both cohorts: CD63 and LAMP1 were among the top 20 differentially expressed genes and were identified as potential mediators of organotropism and favorable survival outcome of M1-PUL patients.

Conclusion

M1-PUL represents a clinically favorable cohort in PDAC patients. Site of relapse might already be predetermined at the time of surgery and could potentially be predicted by gene expression profiling.

•

The retrospective multicenter AIO-YMO-PAK-0515 study defines M1-PUL as a clinically favorable subgroup in PDAC.

•

The number of metastatic lesions, bilateral lung involvement and surgical metastasectomy may serve as prognostic factors.

•

Immune-related gene expression differs between patients with isolated pulmonary relapse versus other sites of relapse.

Lactational performance and plasma and muscle amino acid concentrations in dairy cows fed diets supplying 2 levels of digestible histidine and metabolizable protein

The objective of this experiment was to investigate the effect of dietary levels of digestible histidine (dHis) and MP on lactational performance and plasma and muscle concentrations of free AA in dairy cows. A randomized block design experiment was conducted with 48 Holstein cows, including 20 primiparous, averaging (±SD) 103 ± 22 d in milk and 45 ± 9 kg/d milk yield at the beginning of the experiment. A 2-wk covariate period preceded 12 experimental wk, of which 10 wk were for data and sample collection. Experimental treatments were (1) MP-adequate (MPA) diet with 2.1% dHis of MP (MPA2.1), (2) MPA with 3.0% dHis (MPA3.0), (3) MP-deficient (MPD) diet with 2.1% dHis (MPD2.1), and (4) MPD with 3.0% dHis (MPD3.0). Actual dHis supply was estimated at 64, 97, 57, and 88 g/d, respectively. Diets supplied MP at 110% (MPA) and 96% (MPD) of NRC 2001 dairy model requirements calculated based on DMI and production data during the experiment. Dry matter intake and milk yield data were collected daily, milk samples for composition and blood samples for AA analysis were collected every other week, and muscle biopsies at the end of covariate period, and during wk 12 of the experiment. The overall DMI was not affected by dHis or MP level. Milk yield tended to be increased by 3.0% dHis compared with 2.1% dHis. Milk true protein concentration and yield were not affected by treatments, whereas milk urea nitrogen concentration was lower for MPD versus the MPA diet. Milk fat concentration was lower for MPD versus MPA. There was a MP × dHis interaction for milk fat yield and energy-corrected milk; milk fat was lower for MPD3.0 versus MPD2.1, but similar for cows fed the MPA diet regardless of dHis level whereas energy-corrected milk was greater for MPA3.0 versus MPA2.1 but tended to be lower for MPD3.0 versus MPD2.1. Plasma His concentration was greater for cows fed dHis3.0, and concentration of sum of essential AA was greater, whereas carnosine, 1-Methyl-His and 3-Methyl-His concentrations were lower for cows fed MPA versus MPD diet. Muscle concentration of His was greater for cows fed dHis3.0 treatment. The apparent efficiency of His utilization was increased at lower MP and His levels. Overall, cows fed a corn silage-based diet supplying MP at 110% of NRC (2001) requirements tended to have increased ECM yield and similar milk protein yield to cows fed a diet supplying MP at 96% of requirements. Supplying dHis at 3.0% of MP (or 86 and 96 g/d, for MPD3.0 and MPA3.0, respectively) tended to increase milk yield and increased plasma and muscle concentrations of His but had minor or no effects on other production variables in dairy cows.

Structural and functional consequences of NEDD8 phosphorylation

Ubiquitin (Ub) and Ub-like proteins (Ubls) such as NEDD8 are best known for their function as covalent modifiers of other proteins but they are also themselves subject to post-translational modifications including phosphorylation. While functions of phosphorylated Ub (pUb) have been characterized, the consequences of Ubl phosphorylation remain unclear. Here we report that NEDD8 can be phosphorylated at S65 - the same site as Ub - and that S65 phosphorylation affects the structural dynamics of NEDD8 and Ub in a similar manner. While both pUb and phosphorylated NEDD8 (pNEDD8) can allosterically activate the Ub ligase Parkin, they have different protein interactomes that in turn are distinct from those of unmodified Ub and NEDD8. Among the preferential pNEDD8 interactors are HSP70 family members and we show that pNEDD8 stimulates HSP70 ATPase activity more pronouncedly than unmodified NEDD8. Our findings highlight the general importance of Ub/NEDD8 phosphorylation and support the notion that the function of pUb/pNEDD8 does not require their covalent attachment to other proteins.

Both ubiquitin and NEDD8 can be phosphorylated, but the biological role of NEDD8 phosphorylation remains unclear. Here, the authors identify similarities and differences of ubiquitin and NEDD8 phosphorylation, showing that phosphorylated NEDD8 has a distinct interactome and regulates HSP70 proteins.

P14.79 Differentiation of treatment-related changes from tumor progression following brachytherapy in patients with WHO II and III gliomas using FET PET

BACKGROUND

Following brachytherapy, the differentiation of radiation-induced changes (e.g., radiation necrosis) from actual tumor progression using MRI is challenging. To overcome this diagnostic uncertainty, we evaluated the diagnostic value of O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in glioma patients treated with brachytherapy.

MATERIAL AND METHODS

From 2006–2019, we retrospectively identified WHO grade II or III glioma patients (i) treated with brachytherapy using Iodine-125 seeds, (ii) equivocal or progressive MRI findings inside the radiation field, and (iii) additional FET PET imaging for diagnostic evaluation. Static FET PET parameters such as maximum and mean tumor-to-brain ratios (TBR) and dynamic FET PET parameters (i.e., time-to-peak, slope) were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses and Fisher’s exact test. Diagnoses were confirmed histologically or clinicoradiologically.

RESULTS

Following brachytherapy, suspect MRI findings occurred after a median time of 33 months (range, 5–111 months). In 10 of 21 patients (WHO grade II, n=5; WHO grade III, n=16), treatment-related changes were diagnosed. The best diagnostic performance for identification of treatment-related changes was obtained using maximum TBRs (threshold &lt;3.20; accuracy, 86%; sensitivity, 100%; specificity, 73%; P=0.007). Mean TBRs reached an accuracy of 76% (threshold &lt;2.05; sensitivity, 89%; specificity, 64%; P=0.010). Dynamic PET parameters did not reach statistically significant results.

CONCLUSION

Our data suggest that static FET PET parameters add valuable diagnostic information to diagnose radiation-induced changes in glioma patients treated with brachytherapy.

OS03.3.A Characterization of long-term metabolic changes of irradiated brain metastases using serial dynamic FET PET imaging

BACKGROUND

In the present study, we characterized the long-term metabolic changes of brain metastases irradiated with stereotactic radiosurgery (SRS) by sequential dynamic PET imaging using the radiolabeled amino acid O-(2-[18F]-fluoroethyl)-L-tyrosine (FET). We hypothesized that this approach is of considerable clinical value to diagnose delayed radiation-induced changes.

MATERIAL AND METHODS

From 2010–2021, we retrospectively identified patients with brain metastases from solid extracranial primary tumors who (i) were treated with SRS with or without concurrent immunotherapy using checkpoint inhibitors, (ii) had equivocal or progressive MRI findings after SRS, and (iii) subsequently underwent at least two additional dynamic FET PET scans during follow-up for long-term evaluation. Mean tumor-to-brain ratios (TBR) and the dynamic FET PET parameter time-to-peak were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses. Diagnoses were confirmed histologically or clinicoradiologically.

RESULTS

We identified 36 patients with 98 FET PET scans (median number, 3; range, 2–6). Concurrent to SRS, 8 patients (22%) were treated with checkpoint inhibitors. Following SRS, suspicious MRI findings occurred after a median time of 11 months (range, 2–64 months). Subsequently, FET PET scans were acquired over a median period of 13 months (range, 5–60 months). The overall median follow-up time was 26 months (range, 8–101 months). Twenty-one patients (58%) had delayed radiation-induced changes. TBRs calculated from the last available FET PET scan showed the highest accuracy (92%) to identify delayed radiation-induced changes (threshold, 1.95; P&lt;0.001).

CONCLUSION

FET PET has a high diagnostic accuracy for characterizing the long-term changes of irradiated brain metastases.

Influence of Klebsiella pneumoniae and quinolone treatment on prognosis in patients with pancreatic cancer

BACKGROUND

An increasing body of evidence suggests that microbiota may promote progression of pancreatic ductal adenocarcinoma (PDAC). It was hypothesized that gammaproteobacteria (such as Klebsiella pneumoniae) influence survival in PDAC, and that quinolone treatment may attenuate this effect.

METHODS

This was a retrospective study of patients from the Massachusetts General Hospital (USA) and Ludwig-Maximilians-University (Germany) who underwent preoperative treatment and pancreatoduodenectomy for locally advanced or borderline resectable PDAC between January 2007 and December 2017, and for whom a bile culture was available. Associations between tumour characteristics, survival data, antibiotic use and results of intraoperative bile cultures were investigated. Survival was analysed using Kaplan-Meier curves and Cox regression analysis.

RESULTS

Analysis of a total of 211 patients revealed that an increasing number of pathogen species found in intraoperative bile cultures was associated with a decrease in progression-free survival (PFS) (-1·9 (95 per cent c.i. -3·3 to -0·5) months per species; P = 0·009). Adjuvant treatment with gemcitabine improved PFS in patients who were negative for K. pneumoniae (26·2 versus 15·3 months; P = 0·039), but not in those who tested positive (19·5 versus 13·2 months; P = 0·137). Quinolone treatment was associated with improved median overall survival (OS) independent of K. pneumoniae status (48·8 versus 26·2 months; P = 0·006) and among those who tested positive for K. pneumoniae (median not reached versus 18·8 months; P = 0·028). Patients with quinolone-resistant K. pneumoniae had shorter PFS than those with quinolone-sensitive K. pneumoniae (9·1 versus 18·8 months; P = 0·001).

CONCLUSION

K. pneumoniae may promote chemoresistance to adjuvant gemcitabine, and quinolone treatment is associated with improved survival.

Liver stiffness assessed by shear-wave elastography declines in parallel with immunoregulatory proteins in patients with chronic HCV infection during DAA therapy

BACKGROUND

A rapid decline of liver stiffness (LS) was detected by non-invasive methods in patients with chronic hepatitis C (HCV) infection during treatment with direct-acting antivirals (DAA).

OBJECTIVE

To investigate the influence of inflammation on LS.

METHODS

We prospectively examined LS by sonographic shear-wave elastography in 217 patients during DAA therapy from treatment initiation (BL) to 12 weeks after end of therapy (SVR12). Demographic data, laboratory findings and serum levels of cytokines were determined.

RESULTS

Values of LS decreased from 1.86 m/s to 1.68 m/s (p = 0.01) which was most pronounced in patients who had F4 fibrosis at BL (3.27 m/s to 2.37 m/s; p <  0.001). Initially elevated values of aminotransferases, ferritin, IgG (p <  0.001 each) and international normalized ratio (p <  0.003) declined, thrombocyte count (p = 0.007) increased. Correlations of these laboratory parameters with BL levels of LS measurement (LSM) were most apparent in patients with F1-F3 fibrosis. Tumor necrosis factor (TNF)-α (p = 0.031), interleukin (IL)-10 (p = 0.005) and interferon y inducible protein (IP)-10 (p <  0.001) decreased in parallel with LSM under DAA therapy and corelated with BL values.

CONCLUSION

Decrease of systemic inflammatory parameters correlated with LSM under DAA therapy. We conclude that regression of LSM is attributable to the decline of inflammation rather than reflecting fibrosis.

Alterations in regulatory T cells and immune checkpoint molecules in pancreatic cancer patients receiving FOLFIRINOX or gemcitabine plus nab-paclitaxel

Purpose

This pilot study aimed on generating insight on alterations in circulating immune cells during the use of FOLFIRINOX and gemcitabine/nab-paclitaxel in pancreatic ductal adenocarcinoma (PDAC).

Patients and methods

Peripheral blood mononuclear cells were isolated before and 30 days after initiation of chemotherapy from 20 patients with advanced PDAC. Regulatory T cells (FoxP3+) and immune checkpoints (PD-1 and TIM-3) were analyzed by flow cytometry and immunological changes were correlated with clinical outcome.

Results

Heterogeneous changes during chemotherapy were observed in circulating T-cell subpopulations with a pronounced effect on PD-1+ CD4+/CD8+ T cells. An increase in FoxP3+ or PD-1+ T cells had no significant effect on survival. An increase in TIM3+/CD8+ (but not TIM3+/CD4+) T cells was associated with a significant inferior outcome: median progression-free survival in the subgroup with an increase of TIM-3+/CD8+ T cells was 6.0 compared to 14.0 months in patients with a decrease/no change (p = 0.026); corresponding median overall survival was 13.0 and 20.0 months (p = 0.011), respectively.

Conclusions

Chemotherapy with FOLFIRNOX or gemcitabine/nab-paclitaxel induces variable changes in circulating T-cell populations that may provide prognostic information in PDAC.

Effect of platelet inhibition with perioperative aspirin on survival in patients undergoing curative resection for pancreatic cancer: a propensity score matched analysis

BACKGROUND

The importance of platelets in the pathogenesis of metastasis formation is increasingly recognized. Although evidence from epidemiologic studies suggests positive effects of aspirin on metastasis formation, there is little clinical data on the perioperative use of this drug in pancreatic cancer patients.

METHODS

From all patients who received curative intent surgery for pancreatic cancer between 2014 and 2016 at our institution, we identified 18 patients that took aspirin at time of admission and continued to throughout the inpatient period. Using propensity score matching, we selected a control group of 64 patients without aspirin intake from our database and assessed the effect of aspirin medication on overall, disease-free, and hematogenous metastasis-free survival intervals as endpoints.

RESULTS

Aspirin intake proved to be independently associated with improved mean overall survival (OS) (46.5 vs. 24.6 months, *p = 0.006), median disease-free survival (DFS) (26 vs. 10.5 months, *p = 0.001) and mean hematogenous metastasis-free survival (HMFS) (41.9 vs. 16.3 months, *p = 0.005). Three-year survival rates were 61.1% in patients with aspirin intake vs. 26.3% in patients without aspirin intake. Multivariate cox regression showed significant independent association of aspirin with all three survival endpoints with hazard ratios of 0.36 (95% CI 0.15-0.86) for OS (*p = 0.021), 0.32 (95% CI 0.16-0.63) for DFS (**p = 0.001), and 0.36 (95% CI 0.16-0.77) for HMFS (*p = 0.009).

CONCLUSIONS

Patients in our retrospective, propensity-score matched study showed significantly better overall survival when taking aspirin while undergoing curative surgery for pancreatic cancer. This was mainly due to a prolonged metastasis-free interval following surgery.

Association of Pre-diagnostic Antibody Responses to Escherichia coli and Bacteroides fragilis Toxin Proteins with Colorectal Cancer in a European Cohort

Experimental evidence has implicated genotoxic Escherichia coli (E. coli) and enterotoxigenic Bacteroides fragilis (ETBF) in the development of colorectal cancer (CRC). However, evidence from epidemiological studies is sparse. We therefore assessed the association of serological markers of E. coli and ETBF exposure with odds of developing CRC in the European Prospective Investigation into Nutrition and Cancer (EPIC) study.Serum samples of incident CRC cases and matched controls (n = 442 pairs) were analyzed for immunoglobulin (Ig) A and G antibody responses to seven E. coli proteins and two isoforms of the ETBF toxin via multiplex serology. Multivariable-adjusted conditional logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of sero-positivity to E. coli and ETBF with CRC.The IgA-positivity of any of the tested E. coli antigens was associated with higher odds of developing CRC (OR: 1.42; 95% CI: 1.05-1.91). Dual-positivity for both IgA and IgG to E. coli and ETBF was associated with >1.7-fold higher odds of developing CRC, with a significant association only for IgG (OR: 1.75; 95% CI: 1.04, 2.94). This association was more pronounced when restricted to the proximal colon cancers (OR: 2.62; 95% CI: 1.09, 6.29) compared to those of the distal colon (OR: 1.24; 95% CI: 0.51, 3.00) (pheterogeneity = 0.095). Sero-positivity to E. coli and ETBF was associated with CRC development, suggesting that co-infection of these bacterial species may contribute to colorectal carcinogenesis. These findings warrant further exploration in larger prospective studies and within different population groups.

[Surgery for isolated local recurrence and metachronous oligometastasis in pancreatic cancer]

BACKGROUND

Most patients with pancreatic cancer suffer a relapse, which occurs either locally or systemically in the sense of liver and the lung metastases. Surgery for pancreatic cancer has become more radical due to the increased use of multimodal treatment concepts; however, the role of surgery in cases of recurrence remains controversial.

OBJECTIVE

This review summarizes the surgical treatment options for isolated local recurrence and metachronous oligometastatic pancreatic cancer.

MATERIAL AND METHODS

A selective literature search was carried out and the current evidence for surgical treatment is summarized.

RESULTS

There are currently no randomized studies on surgery for metastatic pancreatic cancer. Currently available data, however, show that after surgery long-term survival of up to 32-47 months after metastasectomy can be achieved, especially in patients with local recurrence or isolated pulmonary metastases with low morbidity and mortality. Individualized treatment concepts including surgical resection after initial systemic therapy seem promising even for liver metastases. The greatest survival benefits are consistently shown for all localizations in patients with a long as possible disease-free interval after the first operation.

CONCLUSION

The treatment of isolated local recurrence or metachronous oligometastatic pancreatic cancer is an interdisciplinary challenge that should be performed in specialized pancreatic treatment centers only. Surgical resection embedded in a multimodal treatment concept can be meaningful in selected cases.

Epstein-Barr virus and human papillomavirus serum antibodies define the viral status of nasopharyngeal carcinoma in a low endemic country

Epstein-Barr virus (EBV) causes nasopharyngeal carcinoma (NPC) in endemic regions, where almost every tumor is EBV-positive. In Western populations, NPC is rare, and human papillomavirus infection (HPV) has been suggested as another viral cause. We validated multiplex serology with molecular tumor markers, to define EBV-positive, HPV-positive and EBV-/HPV-negative NPCs in the United Kingdom, and analyzed survival differences between those groups. Sera from NPC cases (n = 98) and age- and sex-matched controls (n = 142) from the Head and Neck 5000 clinical cohort study were analyzed. IgA and IgG serum antibodies against 13 EBV antigens were measured and compared with EBER in situ hybridization (EBER-ISH) data of 41 NPC tumors (29 EBER-ISH positive, 12 negative). IgG antibodies to EBV LF2 correctly diagnosed EBV-positive NPCs in 28 of 29 cases, while all EBER-ISH negative NPCs were seronegative to LF2 IgG (specificity = 100%, sensitivity = 97%). HPV early antigen serology was compared to HPV molecular markers (p16 expression, HPV DNA and RNA) available for 41 NPCs (13 positive, 28 negative). Serology matched molecular HPV markers in all but one case (specificity = 100%, sensitivity = 92%). EBV and HPV infections were mutually exclusive. Overall, 67% of the analyzed NPCs were defined as EBV-positive, 18% as HPV-positive and 14% as EBV/HPV-negative. There was no statistical evidence of a difference in survival between the three groups. These data provide evidence that both, EBV-positive and HPV-positive NPCs are present in a low incidence country, and that EBV and HPV serum antibodies correlate with the viral status of the tumor.

Effect of Chemotherapeutic Agents on the Expression of Retinoid Receptors and Markers of Cancer Stem Cells and Epithelial-Mesenchymal Transition

A large body of evidence suggests that cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT), as well as expression and function of retinoid receptors, are pivotal features of tumor initiation, progression, and chemoresistance. This is also true for pancreatic ductal adenocarcinoma (PDAC), which represents a clinical challenge due to poor prognosis and increasing incidence. Understanding the above features of cancer cells could open new avenues for PDAC treatment strategies. The aim of this study was to investigate the relation between CSCs, EMT, and retinoid receptors in PDAC after treatment with the chemotherapeutic agents - gemcitabine and 5-fluorouracil. First, we demonstrated the difference in the expression levels of CSC and EMT markers and retinoid receptors in the untreated Mia PaCa-2 and Panc1 cells that also differed in the frequency of spontaneous apoptosis and distribution between the cell cycle phases. Chemotherapy reduced the number of cancer cells in the S phase. Gemcitabine and 5-fluorouracil modulated expression of CSC markers, E-cadherin, and RXRβ in Panc1 but not in Mia PaCa-2 cells. We suggest that these effects could be attributed to the difference in the basal levels of expression of the investigated genes. The obtained data could be interesting in the context of future preclinical research.

Determination of Ochratoxin A in Wine and Beer by Immunoaffinity Column Cleanup and Liquid Chromatographic Analysis with Fluorometric Detection: Collaborative Study

The accuracy, repeatability, and reproducibility characteristics of a liquid chromatographic method for the determination of ochratoxin A (OTA) in white wine, red wine, and beer were established in a collaborative study involving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, and naturally contaminated materials at levels ranging from ≤0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted with a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liquid chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ranging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging from 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative standard deviations for between-laboratories reproducibility (RSDR) ranged from 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were ≤0.4 for the 3 matrixes.

P14.32 Spatial discrepancies between FET PET and conventional MRI in patients with newly diagnosed glioblastoma

BACKGROUND

In patients with glioblastoma, the tissue showing contrast enhancement (CE) in MRI is usually the target for resection or radiotherapy. However, the solid tumor mass typically extends beyond the area of CE. Amino acid PET can detect tumor parts that show no CE. We systematically investigated tumor volumes delineated by amino acid PET and MRI in newly diagnosed, untreated glioblastoma patients.

MATERIAL AND METHODS

Preoperatively, 50 patients with subsequently neuropathologically confirmed glioblastoma underwent O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET, fluid-attenuated inversion recovery (FLAIR), and CE MRI. Areas of CE were manually delineated. FET PET tumor volumes were segmented using a tumor-to-brain ratio ≥ 1.6. The percentage of overlapping volumes (OV), as well as Dice and Jaccard spatial similarity coefficients (DSC; JSC), were calculated. FLAIR images were evaluated visually.

RESULTS

In 86% of patients (n = 43), the FET PET tumor volume was significantly larger than the volume of CE (21.5 ± 14.3 mL vs. 9.4 ± 11.3 mL; P < 0.001). Forty patients (80%) showed both an increased uptake of FET and CE. In these 40 patients, the spatial similarity between FET and CE was low (mean DSC, 0.39 ± 0.21; mean JSC, 0.26 ± 0.16). Ten patients (20%) showed no CE, and one of these patients showed no FET uptake. In 10% of patients (n = 5), increased FET uptake was present outside of areas of FLAIR hyperintensity.

CONCLUSION

Our results show that the metabolically active tumor volume delineated by FET PET is significantly larger than tumor volume delineated by CE. The data strongly suggest that the information derived from FET PET should be integrated into the management of newly diagnosed glioblastoma patients.

FUNDING

This work was supported by the Wilhelm-Sander Stiftung, Germany

P14.17 Differentiation of treatment-related changes from tumor progression: A direct comparison between dynamic FET PET and ADC values obtained from DWI MRI

BACKGROUND

Following brain cancer treatment, the capacity of anatomical MRI to differentiate neoplastic tissue from treatment-related changes (e.g., pseudoprogression) is limited. This study compared apparent diffusion coefficients (ADC) obtained by diffusion-weighted MRI (DWI) with static and dynamic parameters of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET for the differentiation of treatment-related changes from tumor progression.

MATERIAL AND METHODS

Forty-eight pretreated high-grade glioma patients with anatomical MRI findings suspicious for progression (median time elapsed since last treatment, 16 weeks) were investigated using DWI and dynamic FET PET. Maximum and mean tumor-to-brain ratios (TBRmax, TBRmean) as well as dynamic parameters (time-to-peak and slope values) of FET uptake were calculated. For mean ADC calculation, regions-of-interest analyses were performed on ADC maps calculated from DWI co-registered with the contrast-enhanced MR image. Diagnoses were confirmed neuropathologically (21%) or clinicoradiologically. Diagnostic performance was evaluated using receiver-operating-characteristic analyses or Fisher’s exact test for a combinational approach.

RESULTS

Ten of 48 patients had treatment-related changes (21%). The diagnostic performance of FET PET was significantly higher (threshold for both TBRmax and TBRmean, 1.95; accuracy, 83%; AUC, 0.89±0.05; P<0.001) than that of ADC values (threshold ADC, 1.09x10-3 mm2/s; accuracy, 69%; AUC, 0.73±0.09; P=0.13). The addition of static FET PET parameters to ADC values increased the latter’s accuracy to 89%. The highest accuracy was achieved by combining static and dynamic FET PET parameters (93%).

CONCLUSION

Data suggest that static and dynamic FET PET provide valuable information concerning the differentiation of early treatment-related changes from tumor progression and outperform ADC measurement for this highly relevant clinical question.

P14.18 Prognostic value of serial dynamic O-(2-[18F]-fluoroethyl)-L-tyrosine PET in patients with non-resectable malignant glioma undergoing chemoradiation

BACKGROUND

A complete resection of high-grade gliomas (HGG) is associated with improved survival, which, however, cannot be achieved in a considerable number of patients. We here evaluated the prognostic value of serial O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in patients with newly diagnosed, non-resectable astrocytic HGG undergoing chemoradiation with temozolomide.

MATERIAL AND METHODS

Serial dynamic FET PET scans were performed in 18 newly diagnosed patients with molecularly defined, non-resectable HGG at baseline and after chemoradiation (8±3 weeks). Both static (tumor/brain ratios, FET tumor volumes) and dynamic FET PET parameters (time-to-peak, slope), as well as MRI changes according to RANO criteria at first follow-up after chemoradiation (8±3 weeks), were obtained. The predictive ability of FET PET parameters and RANO criteria was evaluated with regard to the progression-free survival (PFS). Using ROC analyses, threshold values for FET PET parameters were obtained. Subsequently, univariate and multivariate survival analyses were performed to assess their predictive power for PFS.

RESULTS

ROC analysis revealed that the mean tumor/brain ratio (AUC, 0.84), FET tumor volume (AUC, 0.89), and slope (AUC, 0.72) at baseline were predictive for a prolonged PFS (9.3 vs. 5.7 months, P=0.05; 10.3 vs. 5.9 months; P=0.03; 13.5 vs. 6.2 months, P=0.02, respectively). Furthermore, FET tumor volume and slope remained significant in the multivariate survival analysis (both P<0.05). In contrast, relative changes of static or dynamic FET PET parameters at follow-up and MRI changes according to RANO criteria were not significant in this albeit small series of patients.

CONCLUSION

Results suggest that before initiation of chemoradiation FET PET parameters at baseline can be used to predict PFS in patients with non-resectable HGG.

Feasibility of single-use 3D-printed instruments for total knee arthroplasty

Aims

This aim of this study was to assess the feasibility of designing and introducing generic 3D-printed instrumentation for routine use in total knee arthroplasty.

Materials and Methods

Instruments were designed to take advantage of 3D-printing technology, particularly ensuring that all parts were pre-assembled, to theoretically reduce the time and skill required during surgery. Concerning functionality, ranges of resection angle and distance were restricted within a safe zone, while accommodating either mechanical or anatomical alignment goals. To identify the most suitable biocompatible materials, typical instrument shapes and mating parts, such as dovetails and screws, were designed and produced.

Results

Before and after steam sterilization, dimensional analysis showed that acrylonitrile butadiene styrene could not withstand the temperatures without dimensional changes. Oscillating saw tests with slotted cutting blocks produced debris, fractures, or further dimensional changes in the shape of Nylon-12 and polymethylmethacrylate (MED610), but polyetherimide ULTEM 1010 was least affected.

Conclusion

The study showed that 3D-printed instrumentation was technically feasible and had some advantages. However, other factors, such as whether all procedural steps can be accomplished with a set of 3D-printed instruments, the logistics of delivery, and the economic aspects, require further study. Cite this article: Bone Joint J 2019;101-B(7 Supple C):115–120

[Endoscopic and surgical treatment of chronic pancreatitis]

With an increasing number of hospital admissions, an average of 16-to 20 days in hospital per year, 34% of patients constantly taking pain medication, 57% in need of enzyme supplementation, and 29% with diabetes mellitus, chronic pancreatitis is a debilitating disease of high socio-economic relevance. In total, 33% of all patients suffering from chronic pancreatitis can no longer practice their original profession. The number of unemployed chronic pancreatitis patients due to prolonged stays in hospital or continued alcohol abuse is known to be as high as 40%. Continued alcohol abuse with a hazard ratio (HR) of 1.6, smoking with a HR of 1.4, and the presence of liver cirrhosis with a HR of 2.5 negatively affects the prognosis of chronic pancreatitis. In a patient cohort burdened with high co-morbidity, endoscopic therapy can provide short-term relief of symptoms. Endotherapy is the first line of management in chronic pancreatitis with symptomatic pancreatobiliary ductal obstruction. Further studies are required in certain key areas such as the use of fully covered self-expanding metallic stents for pancreatic ductal and biliary strictures. Long-term success rates can mainly be achieved by surgical procedures, which can be performed with acceptable morbidity in pancreatic centers. The current review focuses on the advantages and disadvantages of endoscopic and surgical treatment of chronic pancreatitis.

Design of perovskite/crystalline-silicon monolithic tandem solar cells

We present an optical model implemented in the commercial software SETFOS 4.6 for simulating perovskite/silicon monolithic tandem solar cells that exploit light scattering structures. In a first step we validate the model with experimental data of tandem solar cells that either use front- or rear-side textures and extract the internal quantum efficiency of the methyl-ammonium lead iodide (MALI) perovskite sub-cell. In a next step, the software is used to investigate the potential of different device architectures featuring a monolithic integration between the perovskite and silicon sub-cells and exploiting rear- as well as front-side textures for improved light harvesting. We find that, considering the available contact materials, the p-i-n solar cell architecture is the most promising with respect to achievable photocurrent for both flat and textured wafers. Finally, cesium-formamidinium-based perovskite materials with several bandgaps were synthetized, optically characterized and their potential in a tandem device was quantified by simulations. For the simulated layer stack and among the tested materials with bandgaps of 1.7 and 1.6 eV, the one with 1.6 eV bandgap was found to be the most promising, with a potential of reaching a power conversion efficiency of 31%. In order to achieve higher efficiencies using higher band-gap materials, parasitic absorptance in the blue spectral range should be further reduced.

Data Acquisition and Processing in Medicine: Contribution of the Microprocessor

Microprocessor systems facilitate to an increasing extent economical laboratory and process automation in the field of medicine.

The general aspects of hardware architecture and the software problems of the microprocessor are briefly demonstrated. Boundary lines to hardware logic on the one hand and to minicomputers on the other hand and the significance and position of the microprocessor in the biomedical EDP spectrum are discussed. As a reasonable concept for biosignal processing and laboratory automation we propose the »distributed microprocessor system« making use of parallel »basic systems«, which may operate independently or may be controlled by a supervisory processor. By way of a concrete example from our laboratory, some of the problems of realization of microprocessor systems are demonstrated.