In Vivo Thickness of the Healthy Tympanic Membrane Determined by Optical Coherence Tomography

OBJECTIVE

Tympanic membrane (TM) thickness is an important parameter for differentiation between a healthy and a pathologic TM. Furthermore, it is needed for modeling the middle ear function. Endoscopic optical coherence tomography (eOCT) provides the opportunity to measure the TM thickness of the entire TM in vivo.

MATERIALS AND METHODS

A total of 27 healthy ears were examined by eOCT. The system uses a light source with a central wavelength of 1,300 nm. The endoscope with an outer diameter of 3.5 mm provides a field of view of 10 mm and a working distance of 10 mm. Thickness measurements were carried out at 8 points on the TM. Additionally, the existing literature was analyzed, and a mean TM thickness value was determined.

RESULTS

The mean thickness of the TM over all measurement points of the pars tensa was 120.2 μm, and the pars flaccida was significantly thicker with a mean thickness of 177.9 μm. Beyond that, there were no significant differences between the single quadrants. The mean TM thickness in the literature was 88.8 μm.

DISCUSSION

EOCT provides the possibility for in vivo thickness determination of the TM. The mean thickness seems to be higher than in the previous studies, which were mostly carried out ex vivo. Our study takes the three-dimensional refraction into account and provides a method for the refraction correction.

Polarization-Sensitive Optical Coherence Tomography for Monitoring De- and Remineralization of Bovine Enamel In Vitro

Early caries diagnosis still challenges dentistry. Polarization-sensitive optical coherence tomography (PS-OCT) is promising to detect initial lesions non-invasively in depth-resolved cross-sectional visualization. PS-OCT with determined degree of polarization (DOP) imaging provides an intuitive demineralization contrast. The aim of this study is to evaluate the suitability of DOP-based PS-OCT imaging to monitor controlled de- and remineralization progression for the first time and to introduce it as a valid, non-destructive in vitro detection method. Twelve standardized bovine enamel specimens were divided in different groups and demineralized with hydrochloric acid (HCl) as well as partly remineralized with fluoride over a 14-day pH-cycling experiment. The specimens were stored in artificial saliva and sodium chloride (NaCl), respectively. Progress measurements with PS-OCT were made with polarization-sensitive en faceand B-scan mode for qualitative evaluation. The specimens demineralized in HCl showed the most pronounced surface change (lowest DOP) and the most significant increase in depolarization. Additional fluoride treatment and the storage in artificial saliva resulted in the opposite (highest DOP). Therefore, DOP-based PS-OCT imaging appears to be a valuable technique for visualization and monitoring of enamel demineralization and remineralization processes in vitro. However, these findings need to be confirmed in human teeth ex vivo or in situ.

Characteristics of Clinically Classified Oral Lichen Planus in Optical Coherence Tomography: A Descriptive Case-Series Study

Malignant transformation of oral lichen planus (OLP) into oral squamous cell carcinoma is considered as one of the most serious complications of OLP. For the early detection of oral cancer in OLP follow-up, accurate localization of the OLP center is still difficult but often required for confirmatory biopsy with histopathological examination. Optical coherence tomography (OCT) offers the potential for more reliable biopsy sampling in the oral cavity as it is capable of non-invasively imaging the degenerated oral layer structure. In this case-series study with 15 patients, features of clinically classified forms of OLP in OCT cross-sections were registered and correlated with available histologic sections. Besides patients with reticular, atrophic, erosive and plaque-like OLP, two patients with leukoplakia were included for differentiation. The results show that OCT yields information about the epithelial surface, thickness and reflectivity, as well as the identifiability of the basement membrane and the vessel network, which could be used to complement the visual clinical appearance of OLP variants and allow a more accurate localization of the OLP center. This forms the basis for further studies on OCT-assisted non-invasive clinical classification of OLP, with the aim of enabling decision support for biopsy sampling in the future.

Improving patient pathways for systemic lupus erythematosus: a multistakeholder pathway optimisation study

Objective

Among the most significant challenges in SLE are the excessive diagnosis delay and the lack of coordinated care. The aim of the study was to investigate patient pathways in SLE in order to improve clinical and organisational challenges in the management of those with suspected and confirmed SLE.

Methods

We conducted a cross-sectional study of patients with SLE, healthcare providers and other representative stakeholders. Focus groups were conducted, and based on the collected data the most impactful disruption points in SLE patient pathways were identified. A novel framework to improve individual patient pathways in SLE was developed, discussed and validated during a consensus meeting with representative stakeholders.

Results

Six thematic clusters regarding disruption in optimal patient pathways in SLE were identified: appropriate and timely referral strategy for SLE diagnosis; the need for a dedicated consultation during which the diagnosis of SLE would be announced, and following which clarifications and psychological support offered; individualised patient pathways with coordinated care based on organ involvement, disease severity and patient preference; improved therapeutic patient education; prevention of complications such as infections, osteoporosis and cancer; and additional patient support. During the consensus meeting, the broader panel of stakeholders achieved consensus on these attributes and a framework for optimising SLE patient pathways was developed.

Conclusions

We have identified significant disruption points and developed a novel conceptual framework to improve individual patient pathways in SLE. These data may be of valuable interest to patients with SLE, their physicians, health organisations as well as policy makers.

A handheld fiber-optic probe to enable optical coherence tomography of oral soft tissue

This study presents a highly miniaturized, handheld probe developed for rapid assessment of soft tissue using optical coherence tomography (OCT). OCT is a non-invasive optical technology capable of visualizing the sub-surface structural changes that occur in soft tissue disease such as oral lichen planus. However, usage of OCT in the oral cavity has been limited, as the requirements for high-quality optical scanning have often resulted in probes that are heavy, unwieldy and clinically impractical. In this paper, we present a novel probe that combines an all-fiber optical design with a light-weight magnetic scanning mechanism to provide easy access to the oral cavity. The resulting probe is approximately the size of a pen (10 mm 140 mm) and weighs only 10 grams. To demonstrate the feasibility and high image quality achieved with the probe, imaging is performed on the buccal mucosa and alveolar mucosa during routine clinical assessment of six patients diagnosed with oral lichen planus. Results show the loss of normal tissue structure within the lesion, and contrast this with the clear delineation of tissue layers in adjacent inconspicuous regions. The results also demonstrate the ability of the probe to acquire a three-dimensional data volume by manually sweeping across the surface of the mucosa. The findings of this study show the feasibility of using a small, lightweight probe to identify pathological features in oral soft tissue.

OP0282 RITUXIMAB ASSOCIATED WITH SEVERE COVID-19 AMONG PATIENTS WITH INFLAMMATORY ARTHRITIDES: A 1-YEAR MULTICENTER STUDY IN 1116 SUCCESSIVE PATIENTS RECEIVING BIOLOGIC AGENTS

Background:

At a time when vaccines are being prioritized for individuals most at risk, there is currently no clear evidence that risk of SARS-CoV-2 infection is higher for patients with than without inflammatory arthritides (IA). Biologic use was not associated with worse COVID-19 outcomes for yet but the case of rituximab (RTX) remains an issue, given its immunological long term effect, the role of humoral response against SARS-CoV-2 and its indirect effect on T-cell response. A potential association between rituximab and worse COVID-19 outcomes was raised by case reports and retrospective, declarative studies (with few data on the total number of patients exposed).

Objectives:

To address differently the issue of the risk of COVID-19 related to RTX and limit biases, we examined the occurrence of severe COVID-19 in all patients receiving intravenous biologic agents at day-hospitals during the pandemic in France.

Methods:

From 1st September 2019 to 1st January 2021, we analyzed patients with IA prospectively treated with intravenous biologic agents (RTX, abatacept, infliximab or tocilizumab) in 7 clinical centers in France. We obtained the list of patients receiving intravenous biologic agents in each center from the pharmacist of the hospitals. Therefore, all consecutive patients receiving 1 of the 4 drugs at the time of the study were included in each center. Patients with no follow-up after September 2020 were systematically contacted by phone. The occurrence of a severe COVID -19 (i.e. resulting in death, hospitalization or increase in length of hospitalization related to COVID-19) was the primary outcome criteria.

Results:

In total, 1116 patients receiving intravenous biologic agents were included: 449 with infliximab, 392 RTX, 170 tocilizumab and 105 abatacept. From 1st September 2019, the median follow-up time was 15 months (interquartile range 14-16). In total, 10 cases of severe COVID-19 occurred, 9 treated with RTX and 1 with infliximab (supplementary Table 1). Four deaths occurred in our cohort during follow-up but none was related to COVID-19 (1 patient treated by tocilizumab, 1 by RTX and 2 by infliximab). In univariate analysis, the proportion of severe COVID-19 was significantly higher for patients receiving RTX than other biologic agents (9/392 vs 1/724, p=0.0003, OR [95%CI] 17.0 [2.1-134.6]). To take into account potential confounders, we performed multivariate analysis accounting for baseline parameters that differed between RTX and other biologic groups. RTX remained significantly associated with risk of severe COVID-19 (p=0.019) (Table 1).

Patient characteristicsRituximab (n= 392)Other bDMARDs (n= 724)Univariate analysis, p-valueMultivariate analysis, p-valueMedian age (years), — [IQR]64 [56-71]57.3 [47.0-67.0]< 0.00010.51Female — n (%)285 (72.7)426 (58.8)< 0.00010.58IA diagnosis< 0.00010.12Median follow-up from 1st September to last news14 [13-15]15 [14-16]< 0.00010.86Confirmed severe COVID-19 cases —n (%)9 (2.3)1 (0.1)0.00030.019Comorbidities** (history of) — n (%) Cardiovascular disease60 (15.4)167 (23.1)0.00250.77 Chronic lung disease,92 (23.5)84 (11.6)0.00010.88Median BMI (kg/m2) — [IQR]25.8 [23.2-29.4]27.3 [23.4-31.2]0.0150.80Treatments — n (%) Methotrexate179 (45.8)322 (44.5)0.71 Leflunomide41 (10.5)39 (5.4)0.00230.43 Hydroxychloroquine35 (8.9)24 (3.3)0.00010.15 Glucocorticoids127 (41.8)100 (19.4)< 0.00010.36 Median dose (mg/day) — [IQR]1 [0-5]0 [0-0]< 0.0001

No significant difference in terms of baseline gammaglobulins (p=0.46) or number of previous RTX infusions (p=0.57) was observed among patients receiving RTX with or without a severe COVID-19.

Conclusion:

The present results highly indicate increased risk of severe COVID-19 with RTX. Among patients with inflammatory arthritides, those receiving RTX should be prioritized for vaccination against SARS-CoV-2, sufficiently long before infusion/reinfusion and the immunization checked, or an alternative targeted therapy proposed.

Acknowledgements:

We thank Dr. Karine Demesmay and all the pharmacists who helped us for this study.

Disclosure of Interests:

Renaud FELTEN Speakers bureau: Abbvie, Biogen, BMS, Lilly, Novartis, Pfizer, Pierre-Marie Duret: None declared, Elodie BAUER: None declared, Marc Ardizzone: None declared, H Julien Djossou: None declared, Jean-Hugues Salmon: None declared, Cassandre Fabre: None declared, Julia Walther: None declared, Isabelle CHARY VALCKENAERE: None declared, marion geoffroy: None declared, Laurent Messer: None declared, Francis Berenbaum: None declared, Martin SOUBRIER: None declared, Jérémie SELLAM Speakers bureau: MSD, Pfizer, Abbvie, Roche, BMS, Lilly, Janssen, Novartis, Galapagos, Sandoz, Fresenius Kabi, Grant/research support from: Roche, MSD, Pfizer, Jacques-Eric Gottenberg: None declared

Does DDI-Predictor Help Pharmacists to Detect Drug-Drug Interactions and Resolve Medication Issues More Effectively?

The characterization of drug-drug interactions (DDIs) may require the use of several different tools, such as the thesaurus issued by our national health agency (i.e., ANSM), the metabolic pathways table from the Geneva University Hospital (GUH), and DDI-Predictor (DDI-P). We sought to (i) compare the three tools’ respective abilities to detect DDIs in routine clinical practice and (ii) measure the pharmacist intervention rate (PIR) and physician acceptance rate (PAR) associated with the use of DDI-P. The three tools’ respective DDI detection rates (in %) were measured. The PIRs and PARs were compared by using the area under the curve ratio given by DDI-P (R_AUC) and applying a chi-squared test. The DDI detection rates differed significantly: 40.0%, 76.5%, and 85.2% for ANSM (The National Agency for the Safety of Medicines and Health Products), GUH and DDI-P, respectively (p < 0.0001). The PIR differed significantly according to the DDI-P’s R_AUC: 90.0%, 44.2% and 75.0% for R_AUC ≤ 0.5; R_AUC 0.5–2 and R_AUC > 2, respectively (p < 0.001). The overall PAR was 85.1% and did not appear to depend on the R_AUC category (p = 0.729). Our results showed that more pharmacist interventions were issued when details of the strength of the DDI were available. The three tools can be used in a complementary manner, with a view to refining medication adjustments.

Immunosuppressive agents for rheumatoid arthritis: a systematic review of clinical trials and their current development stage

Aims

With the arrival of conventional synthetic (csDMARDs), biological (bDMARDS) and then targeted synthetic (tsDMARDs) disease-modifying anti-rheumatic drugs, the therapeutic arsenal against rheumatoid arthritis (RA) has recently expanded. However, there are still some unmet needs for patients who do not achieve remission and continue to worsen despite treatments. Of note, most randomized controlled trials show that, for methotrexate-inadequate responders, only 20% of patients are ACR70 responders. With our better understanding of RA pathogenesis, finding new treatments is a necessary challenge. The objective of our study was to analyse the whole pipeline of immunosuppressive and immunomodulating drugs evaluated in RA and describe their mechanisms of action and stage of clinical development.

Methods

We conducted a systematic review of all drugs in clinical development in RA, in 17 online registries of clinical trials.

Results

The search yielded 4652 trials, from which we identified 243 molecules. Those molecules belong to csDMARDs (n = 22), bDMARDs (n = 118), tsDMARDs (n = 103). Twenty-four molecules are already marketed in RA in at least one country: eight csDMARDs, 10 bDMARDs and six tsDMARDs. Molecules under current development are mainly bDMARDs (n = 34) and tsDMARDs (n = 33). Seven of those have reached phase III. A large number of molecules (150/243, 61.7%) have been withdrawn.

Conclusion

Despite the availability of 24 marketed molecules, the development of new targeted molecules is ongoing with a total of 243 molecules in RA. With seven molecules currently reaching phase III, we can expect an increase in the armamentarium in the years to come.

Prescribing practices of lopinavir/ritonavir, hydroxychloroquine and azithromycin during the COVID-19 epidemic crisis and pharmaceutical interventions in a French teaching hospital

Objective

The aims of this study were to describe prescribing practices of lopinavir/ritonavir, hydroxychloroquine and azithromycin during the COVID-19 epidemic crisis (primary endpoint), then to characterise pharmaceutical interventions (PIs) targeted to these medications and evaluate the impact of these PIs on prescribers’ practices (secondary end-points).

Methods

This retrospective observational study was carried out at the University Hospital of Strasbourg (France) from March to April 2020. The analysed population excluded patients from intensive care units but included all other adult patients with COVID-19 who received at least one dose of lopinavir/ritonavir combination, hydroxychloroquine or azithromycin, while inpatients. Analyses were performed by using data extracted from electronic medical records.

Result

During the study period, 278 patients were included. A rapid decrease in lopinavir/ritonavir prescriptions was observed. This was accompanied by an increase in hydroxychloroquine and azithromycin prescriptions until the end of March, followed by a decrease leading to the disappearance of these two medications in April. The pharmaceutical analysis of the prescriptions resulted in 59 PIs of which 21 were associated with lopinavir/ritonavir, 32 with hydroxychloroquine and 6 with azithromycin. Regarding the medication-related problems, the most frequent ones were incorrect treatment durations (n=32 (54.2%)), drug interactions with potential torsadogenic reactions (n=14 (23.7%)) and incorrect dosing (n=6 (10.2%)). From the 59 PIs, 48 (81.4%) were accepted and physicians adjusted the medication regimens in a timely manner.

Conclusion

This study demonstrated the value—even more meaningful in a crisis situation—of a strong synergy between physicians and pharmacists for patient-safety focused practices.

In Vivo Endoscopic Optical Coherence Tomography of the Healthy Human Oral Mucosa: Qualitative and Quantitative Image Analysis

To date, there is still a lack of reliable imaging modalities to improve the quality of consultation, diagnostic and medical examinations of the oral mucosa in dentistry. Even though, optical technologies have become an important element for the detection and treatment of different diseases of soft tissue, for the case of oral screenings the evidence of the benefit in comparison to conventional histopathology is mostly still pending. One promising optical technology for oral diagnostics is optical coherence tomography (OCT). To prove the potential of OCT, even the amount of freely accessible OCT data is not sufficient to describe the variance of healthy human oral soft tissue in vivo. In order to remedy this deficiency, the present study provides in vivo OCT cross sections of the human oral mucosa of the anterior and posterior oral cavity as well as the oropharynx of 47 adult volunteers. A collection of representative OCT cross sections forms the basis for a randomized blinded image analysis by means of seven criteria to assess the main features of the superficial layers of the human oral mucosa and to determine its correlation to regional features known from hematoxylin and eosin (HE) stained histology.

Towards quantitative demineralization imaging for the assessment of carious lesions based on PS-OCT

Assessing the stage and progression of enamel demineralization non-invasively is of high interest in conservative dentistry. By examining tooth samples with suspected occlusal lesions, we show the potential of depolarization imaging based on polarization-sensitive optical coherence tomography for the assessment of carious lesions and validate the results by co-registered X-ray micro-computed tomography volumes.

AB0332 IMMUNOSUPPRESSIVE AND IMMONOMODULATING AGENTS IN RHEUMATOID ARTHRITIS: A SYSTEMATIC REVIEW OF CLINICAL TRIALS AND THEIR CURRENT DEVELOPMENT STAGE

Background:

Rheumatoid arthritis (RA) is the most frequent chronic inflammatory diseases with an incidence of 0.5% to 1%. Therapeutic arsenal of RA has continuously expanded in recent years with the recent therapeutic progress with the arrival of conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), biological (bDMARDs) and targeted synthetic (tsDMARDs), JAK inhibitors. However, there are still some unmet needs for patients who do not achieve remission and who continue to worsen despite treatments. Of note, only approximately 40% of patients are ACR70 responders, in most randomized controlled trials. For these patients, finding new therapeutic avenues is challenging.

Objectives:

The objective of our study was to analyze the whole pipeline of immunosuppressive and immunomodulating drugs evaluated in RA and describe their mechanisms of action and stage of clinical development.

Methods:

We conducted a systematic review of all drug therapies in clinical development in RA in 17 databases of international clinical trials. Inclusion criterion: study from one of the databases using the keywords “Rheumatoid arthritis” (search date: June 1, 2019). Exclusion criteria: non-drug trials, trials not related to RA or duplicates. We also excluded dietary regimen or supplementations, cellular therapies, NSAIDs, glucorticoids or their derivatives and non-immunosuppressive or non-immunomodulating drugs. For each csDMARD, bDMARD and tsDMARD, we considered the study at the most advanced stage. For bDMARDs, we did not take into account biosimilars.

Results:

The research identified 4652 trials, of which 242 for 243 molecules met the inclusion and exclusion criteria. The developed molecules belong to csDMARDs (n=21), bDMARDs (n=117), tsDMARDs (n=105).

Among the 21 csDMARDs molecules: 8 (38%) has been withdrawn, 4 (19%) are already labelled in RA (hydroxychloroquine, leflunomide, methotrexate and sulfasalazine) and 9 (43%) are in development: 1 (11%) is in phase I/II, 5 (56%) in phase II, 3 (33%) in phase IV.

Among the 117 bDMARDs molecules: 69 (59%) has been withdrawn, 9 (8%) are labeled in RA (abatacept, adalimumab, anakinra, certolizumab, etanercept, golimumab, infliximab, rituximab, sarilumab, tocilizumab) and 39 (33%) are in development: 9 (23%) in phase I, 3 (8%) in phase I/II, 21 (54%) in phase II, 5 (12%) are in phase III, 1 (3%) in phase IV. bDMARDs currently under development target B cells (n=4), T cells (n=2), T/B cells costimulation (n=2),TNF alpha (n=2), Interleukine 1 or his receptor (n=3), Interleukine 6 or his receptor (n=7), Interleukine 17 (n=4), Interleukine 23 (n=1), GM-CSF (n=1), other cytokines or chemokines (n=5), integrins or adhesion proteins (n=3), interferon receptor (n=1) and various other targets (n=4).

Among the 105 tsDMARDs molecules: 64 (61%) has been withdrawn, 6 (6%) JAK inhibitors, have just been or will probably soon be labelled (baricitinib, filgotinib, peficitinib, tofacitinib and upadacitinib), 35 (33%) are in development: 8 (24%) in phase I, 26 (74%) in phase II, 1 (3%) in phase III and. tsDMARDs currently under development target tyrosine kinase (n=12), janus kinase (JAK) (n=3), sphingosine phostate (n=3), PI3K pathway (n=1), phosphodiesterase-4 (n=3) B cells signaling pathways (n=3) and various other targets (n=10).

Conclusion:

A total of 242 therapeutic trials involving 243 molecules have been or are being evaluated in RA. This development does not always lead to new treatments since 141 (58%) have already been withdrawn. Hopefully, some of the currently evaluated drugs will contribute to improve the therapeutic management of RA patients, requiring a greater personalization of therapeutic strategies, both in the choice of molecules and their place in therapeutic sequences.

Disclosure of Interests:

Julien Blaess: None declared, Julia Walther: None declared, Jacques-Eric Gottenberg Grant/research support from: BMS, Pfizer, Consultant of: BMS, Sanofi-Genzyme, UCB, Speakers bureau: Abbvie, Eli Lilly and Co., Roche, Sanofi-Genzyme, UCB, Jean Sibilia: None declared, Laurent Arnaud: None declared, Renaud FELTEN: None declared

[Conservative treatment of periprosthetic humeral fractures years after cemented fracture prostheses : A case series]

BACKGROUND

The exact incidence of postoperative periprosthetic humeral fractures (PPHF) months or years after fracture-related implantation of a hemiprosthesis is unknown. The currently available literature is predominantly concerned with operative treatment approaches. As a rule, these involved older patients and severe fracture conditions so that severe complications and unsatisfactory healing results were described. This article presents an alternative conservative treatment approach which is discussed based on the results of treatment.

PATIENTS AND METHODS

Between 2011 and 2016 a conservative treatment of 5 female patients with PPHF could be carried out. Of the patients 4 were clinically and radiologically controlled at a mean follow-up time of 23 months. The fifth patient died 2 months after the trauma and only partial information of the treatment was available.

RESULT

There were no intrahospital complications and just one posthospital complication. In the case of the patient who later died, repeated and unauthorized removal of the upper arm brace occurred in the nursing institution resulting in a lesion of the radial nerve. Of the four patients who completed treatment, three were very satisfied with the outcome of treatment. The mean DASH (Disabilities of Arm, Shoulder and Hand) and Oxford shoulder scores were on average 74 and 25 points, respectively. At the time of the follow-up examination all patients were free of pain, without the use of analgesics; however, there were still some limitations in the activities of daily life, which in three of the four patients was similar to the results following implantation of the fracture prosthesis.

CONCLUSION

The conservative treatment of PPHF can be a safe treatment option in multimorbid and chronically ill patients. A close outpatient control and good patient compliance are important. In incompliant and dementia patients, the risk of failure of conservative treatment is increased.

Depth-resolved birefringence imaging of collagen fiber organization in the human oral mucosa in vivo

Stromal collagen organization has been identified as a potential prognostic indicator in a variety of cancers and other diseases accompanied by fibrosis. Changes in the connective tissue are increasingly considered for grading dysplasia and progress of oral squamous cell carcinoma, investigated mainly ex vivo by histopathology. In this study, polarization-sensitive optical coherence tomography (PS-OCT) with local phase retardation imaging is used for the first time to visualize depth-resolved (i.e., local) birefringence of healthy human oral mucosa in vivo. Depth-resolved birefringence is shown to reveal the expected local collagen organization. To demonstrate proof-of-principle, 3D image stacks were acquired at labial and lingual locations of the oral mucosa, chosen as those most commonly affected by cancerous alterations. To enable an intuitive evaluation of the birefringence images suitable for clinical application, color depth-encoded en-face projections were generated. Compared to en-face views of intensity or conventional cumulative phase retardation, we show that this novel approach offers improved visualization of the mucosal connective tissue layer in general, and reveals the collagen fiber architecture in particular. This study provides the basis for future prospective pathological and comparative in vivo studies non-invasively assessing stromal changes in conspicuous and cancerous oral lesions at different stages.

Endoscopic optical coherence tomography with wide field-of-view for the morphological and functional assessment of the human tympanic membrane

An endoscopic optical coherence tomography (OCT) system with a wide field-of-view of 8 mm is presented, which combines the image capability of endoscopic imaging at the middle ear with the advantages of functional OCT imaging, allowing a morphological and functional assessment of the human tympanic membrane. The endoscopic tube has a diameter of 3.5 mm and contains gradient-index optics for simultaneous forward-viewing OCT and video endoscopy. The endoscope allows the three-dimensional visualization of nearly the entire tympanic membrane. In addition, the oscillation of the tympanic membrane is measured spatially resolved and in the frequency range between 500 Hz and 5 kHz with 125 Hz resolution, which is realized by phase-resolved Doppler OCT imaging during acoustical excitation with chirp signals. The applicability of the OCT system is demonstrated in vivo. Due to the fast image acquisition, structural and functional measurements are only slightly affected by motion artifacts.

Imaging of the human tympanic membrane by endoscopic optical coherence tomography

Endoscopic optical coherence tomography is a non-invasive and contactless imaging technique based on white light interferometry. It enables high-resolution three-dimensional imaging of scattering tissue up to a depth of about 2 mm. In addition, Doppler-OCT can detect sub-resolution movements. These features can be used to examine the tympanic membrane, the surrounding tissue and nearby areas of the tympanic cavity. For this purpose, we present an endoscopic OCT system, which provides access to the tympanic membrane. The design of the endoscope is based on a gradientindex (GRIN) lens system. This allows a broad field of view and a large working distance. An additional VIS beam path allows visual imaging and orientation inside the auditory canal. Therefore, illumination fibers are attached a round the GRIN-system. The resulting endoscope has a length of 55 mm and a diameter of 3.5 mm. By attaching an earphone and a probe microphone, the oscillation of the tympanic membrane can be measured under acoustic stimulation. With the endoscopic OCT system, we provide an examination tool for the diagnosis of a broad number of diseases like conductive hearing loss.

Cross-sectional and en-face depolarization imaging for the assessment of dental lesions

Dental caries is one of the most widespread diseases and the early and non-invasive detection of carious lesions remains an ongoing topic in biomedical research. In contrast, optical coherence tomography (OCT) is an emerging, non-invasive imaging technique for near-surface structures, that has already proved its capability for manifold biomedical applications and can be extended by several modalities such as polarization sensitivity. We have recently shown that polarization sensitive OCT combined with an algorithm for depolarization imaging, visualizing the degree of polarization uniformity (DOPU), is a promising tool for the detection and assessment of carious lesions. In this paper, we evaluate different visualization approaches based on both the intensity and DOPU data with cross-sectional and en-face representations and discuss limitations and the potential of the proposed method for the assessment of dental lesions on the example of a molar tooth with a brown spot.

Visualization of interfacial adhesive defects at dental restorations with spectral domain and polarization sensitive optical coherence tomography

Restoration loss based on interfacial adhesive defects and associated caries at the restoration margin are the main causes for invasive replacement of dental restorations. Assessment of the interfacial quality based on clinical inspection and radiographic examination is often difficult and not reliable. In this work, we present spectral domain optical coherence tomography (SDOCT) and polarization sensitive optical coherence tomography (PSOCT) for the evaluation of tooth-composite bond failure. Imaging of two composite restorations at the occlusal surface are presented using intensity-based images obtained by SDOCT and PSOCT based degree of polarization uniformity (DOPU). Both modalities revealed several defects beneath the surface such as inhomogeneous adhesive layers, marginal gaps and bubbles. In addition, DOPU representation showed an inhomogeneous structure within the composite material. OCT based imaging of dental restorations could add a valuable diagnostic tool for the evaluation of structural defects in clinical practice. The representation of polarization characteristics with the DOPU algorithm provides further information on the homogeneity of the restoration.

Application of optical and spectroscopic technologies for the characterization of carious lesions in vitro

The detection of the beginning demineralization process of dental hard tissue remains a challenging task in dentistry. As an alternative to bitewing radiographs, optical and spectroscopic technologies showed promising results for caries diagnosis. The aim of the present work is to give an overview of optical and spectroscopic properties of healthy and carious human teeth in vitro by means of Raman spectroscopy (RS), optical coherence tomography (OCT) and hyperspectral imaging (HSI). OCT was able to represent microstructural changes below the enamel surface and revealed increased scattering for white spot lesions and a white scattering trail for deeper lesions. HSI showed similar absorbance characteristics for healthy and demineralized enamel over the entire spectrum and a characteristic absorbance peak at 550 nm for discolored lesions. Already at early carious stages (white spot), we found a distinct loss of hydroxylapatite-related intensity at 959 cm−1 in demineralized regions with RS. Healthy and demineralized tooth surfaces can be distinguished at different signal levels by means of RS, OCT and HSI. The presented modalities provide additional information to the current clinical diagnosis of caries such as microstructural changes, quantification of the demineralization and imaging of caries-related chemical changes.

Inhibition of the PI3K but not the MEK/ERK pathway sensitizes human glioma cells to alkylating drugs

Background

Intrinsic chemoresistance of glioblastoma (GBM) is frequently owed to activation of the PI3K and MEK/ERK pathways. These signaling cascades are tightly interconnected however the quantitative contribution of both to intrinsic resistance is still not clear. Here, we aimed at determining the activation status of these pathways in human GBM biopsies and cells and investigating the quantitative impact of both pathways to chemoresistance.

Methods

Receptor tyrosine kinase (RTK) pathways in temozolomide (TMZ) treatment naive or TMZ resistant human GBM biopsies and GBM cells were investigated by proteome profiling and immunoblotting of a subset of proteins. Resistance to drugs and RTK pathway inhibitors was assessed by MTT assays. Apoptotic rates were determined by Annexin V staining and DNA damage with comet assays and immunoblotting.

Results

We analyzed activation of RTK pathways by proteome profiling of tumor samples of patients which were diagnosed a secondary GBM and underwent surgery and patients which underwent a second surgery after TMZ treatment due to recurrence of the tumor. We observed substantial activation of the PI3K and MEK/ERK pathways in both groups. However, AKT and CREB phosphorylation was reduced in biopsies of resistant tumors while ERK phosphorylation remained unchanged. Subsequent proteome profiling revealed that multiple RTKs and downstream targets are also activated in three GBM cell lines. We then systematically describe a mechanism of resistance of GBM cell lines and human primary GBM cells to the alkylating drugs TMZ and cisplatin. No specific inhibitor of the upstream RTKs sensitized cells to drug treatment. In contrast, we were able to restore sensitivity to TMZ and cisplatin by inhibiting PI3K in all cell lines and in human primary GBM cells. Interestingly, an opposite effect was observed when we inhibited the MEK/ERK signaling cascade with two different inhibitors.

Conclusions

Temozolomide treatment naive and TMZ resistant GBM biopsies show a distinct activation pattern of the MEK/ERK and PI3K signaling cascades indicating a role of these pathways in resistance development. Both pathways are also activated in GBM cell lines, however, only the PI3K pathway seems to play a crucial role in resistance to alkylating agents and might serve as drug target for chemosensitization.

In vivo imaging in the oral cavity by endoscopic optical coherence tomography

The common way to diagnose hard and soft tissue irregularities in the oral cavity is initially the visual inspection by an experienced dentist followed by further medical examinations, such as radiological imaging and/or histopathological investigation. For the diagnosis of oral hard and soft tissues, the detection of early transformations is mostly hampered by poor visual access, low specificity of the diagnosis techniques, and/or limited feasibility of frequent screenings. Therefore, optical noninvasive diagnosis of oral tissue is promising to improve the accuracy of oral screening. Considering this demand, a rigid handheld endoscopic scanner was developed for optical coherence tomography (OCT). The novelty is the usage of a commercially near-infrared endoscope with fitting optics in combination with an established spectral-domain OCT system of our workgroup. By reaching a high spatial resolution, in vivo images of anterior and especially posterior dental and mucosal tissues were obtained from the oral cavity of two volunteers. The convincing image quality of the endoscopic OCT device is particularly obvious for the imaging of different regions of the human soft palate with highly scattering fibrous layer and capillary network within the lamina propria.

Quantitative analysis of receptor-mediated uptake and pro-apoptotic activity of mistletoe lectin-1 by high content imaging

Ribosome inactivating proteins (RIPs) are highly potent cytotoxins that have potential as anticancer therapeutics. Mistletoe lectin 1 (ML1) is a heterodimeric cytotoxic protein isolated from European Mistletoe and belongs to RIP class II. The aim of this project was to systematically study ML1 cell binding, endocytosis pathway(s), subcellular processing and apoptosis activation. For this purpose, state of the art cell imaging equipment and automated image analysis algorithms were used. ML1 displayed very fast binding to sugar residues on the membrane and energy-dependent uptake in CT26 cells. The co-staining with specific antibodies and uptake blocking experiments revealed involvement of both clathrin-dependent and -independent pathways in ML1 endocytosis. Co-localization studies demonstrated the toxin transport from early endocytic vesicles to Golgi network; a retrograde road to the endoplasmic reticulum. The pro-apoptotic and antiproliferative activity of ML1 were shown in time lapse movies and subsequently quantified. ML1 cytotoxicity was less affected in multidrug resistant tumor cell line 4T1 in contrast to commonly used chemotherapeutic drug (ML1 resistance index 6.9 vs 13.4 for doxorubicin; IC₅₀: ML1 1.4 ng/ml vs doxorubicin 24000 ng/ml). This opens new opportunities for the use of ML1 as an alternative treatment in multidrug resistant cancers.

Detection of carious lesions utilizing depolarization imaging by polarization sensitive optical coherence tomography

As dental caries is one of the most common diseases, the early and noninvasive detection of carious lesions plays an important role in public health care. Optical coherence tomography (OCT) with its ability of depth-resolved, high-resolution, noninvasive, fast imaging has been previously recognized as a promising tool in dentistry. Additionally, polarization sensitive imaging provides quantitative measures on the birefringent tissue properties and can be utilized for imaging dental tissue, especially enamel and dentin. By imaging three exemplary tooth samples ex vivo with proximal white spot, brown spot, and cavity, we show that the combination of polarization sensitive OCT and the degree of polarization uniformity (DOPU) algorithm is a promising approach for the detection of proximal carious lesions due to the depolarization contrast of demineralized tissue. Furthermore, we investigate different sizes of the DOPU evaluation kernel on the resulting contrast and conclude a suitable value for this application. We propose that DOPU provides an easy to interpret image representation and appropriate contrast for possible future screening applications in early caries diagnostics.

In vivo imaging of human oral hard and soft tissues by polarization-sensitive optical coherence tomography

Since optical coherence tomography (OCT) provides three-dimensional high-resolution images of biological tissue, the benefit of polarization contrast in the field of dentistry is highlighted in this study. Polarization-sensitive OCT (PS OCT) with phase-sensitive recording is used for imaging dental and mucosal tissues in the human oral cavity in vivo. An enhanced polarization contrast of oral structures is reached by analyzing the signals of the co- and crosspolarized channels of the swept source PS OCT system quantitatively with respect to reflectivity, retardation, optic axis orientation, and depolarization. The calculation of these polarization parameters enables a high tissue-specific contrast imaging for the detailed physical interpretation of human oral hard and soft tissues. For the proof-of-principle, imaging of composite restorations and mineralization defects at premolars as well as gingival, lingual, and labial oral mucosa was performed in vivo within the anterior oral cavity. The achieved contrast-enhanced results of the investigated human oral tissues by means of polarization-sensitive imaging are evaluated by the comparison with conventional intensity-based OCT.

Functional and morphological imaging of the human tympanic membrane with endoscopic optical coherence tomography

In this ex vivo feasibility study, endoscopic structural and functional optical coherence tomography (OCT) imaging with a field of view of 8 mm is presented allowing the inspection of nearly the entire tympanic membrane through the ear canal. The endoscope utilizes a gradient index optics for simultaneous OCT and video endoscopy. Additionally, Doppler-OCT allows the measurement of the tympanic membrane oscillation. Due to the fast image acquisition, only minor motion artifacts have been observed, which don’t affect the image quality. In conclusion, endoscopic OCT is considered as a promising tool for the comprehensive examination of the human middle ear.

In vivo imaging of murine vasodynamics analyzing different mouse strains by optical coherence tomography

BACKGROUND AND AIMS

We tried to circumvent the limitations of standard organ chamber experiments using in vivo optical coherence tomography (OCT) to analyze the vascular function of small arteries in different mouse strains.

METHODS

OCT images were acquired with a two-axis galvanometer scanner head. Time series (3 frames per second, 300 × 512 pixel per frame) of cross-sectional images were analyzed with image processing software measuring the time course of vessel lumen dynamics. Vascular function of murine saphenous artery of male C57BL/6 (wild-type) and hypercholesterolemic LDLR knockout (LDLR^-/-) mice was analyzed at 6 weeks and after 14 weeks feeding a control or high-fat diet containing 21.2% butter fat and 2.1 mg/kg cholesterol. Vasoconstriction and vasodilation was analyzed by OCT in response to 80 mM K⁺ and 1 mM SNP.

RESULTS

The OCT technique allowed determination of inner diameter, flow resistance, maximal velocity of diameter change and time to half-maximal diameter change in murine saphenous arteries of wild-type and LDLR^-/- mice. LDLR^-/- had impaired vasodilation and changes in vasodynamics after 14 weeks on control or high-fat diet, compared to wild-type mice. The diameter of the saphenous artery of LDLR^-/- mice was reduced after vasoconstriction (38 ± 7 μm vs 12 ± 6 μm) and vasodilation (245 ± 8 μm vs 220 ± 10 μm) (P < 0.05 vs C57BL/6).

CONCLUSION

OCT was used as an innovative method to image vascular function of small arteries of wild-type and hypercholesterolemic LDLR^-/- mice after high-fat diet. The method offers the ability to display differences in the vasodynamics at early stages of endothelial dysfunction in vivo.

Impact of a detector dead time in phase-resolved Doppler analysis using spectral domain optical coherence tomography

For any oblique sample movement containing a transverse velocity component, the commonly used linear relationship between the phase shift and the axial velocity component is erroneous for spectrometer-based optical coherence tomography (spectral domain OCT, SD-OCT). We recently proposed a new Doppler model that assumes a continuous integration of the photocurrent. In this research, we extend the model for detectors with a shutter control by taking detector dead time into account. We present the new relation between phase shift and oblique sample displacement as well as the correlation of the phases of consecutive depth scans, in dependency on the detector dead times ranging from 5% to 90%, as numerically calculated universal contour plots, which are valid for any center wavelength and sample beam size. We found that detector dead time is recommended, especially for oblique sample motion. The reason for this recommendation is the achieved linear relation between the phase shift and the axial velocity component in the velocity range relevant for in vivo measurements, despite the signal damping due to shorter exposure time of the line detector. The theoretical Doppler model is verified using a 1% Intralipid flow phantom model. Because of the results of this research, we believe future measurements in Doppler SD-OCT can be more simple and more accurate by setting a shutter control for the line detector used.

Imaging of nanoparticle-labeled stem cells using magnetomotive optical coherence tomography, laser speckle reflectometry, and light microscopy

Cell transplantation and stem cell therapy are promising approaches for regenerative medicine and are of interest to researchers and clinicians worldwide. However, currently, no imaging technique that allows three-dimensional in vivo inspection of therapeutically administered cells in host tissues is available. Therefore, we investigate magnetomotive optical coherence tomography (MM-OCT) of cells labeled with magnetic particles as a potential noninvasive cell tracking method. We develop magnetomotive imaging of mesenchymal stem cells for future cell therapy monitoring. Cells were labeled with fluorescent iron oxide nanoparticles, embedded in tissue-mimicking agar scaffolds, and imaged using a microscope setup with an integrated MM-OCT probe. Magnetic particle-induced motion in response to a pulsed magnetic field of 0.2 T was successfully detected by OCT speckle variance analysis, and cross-sectional and volumetric OCT scans with highlighted labeled cells were obtained. In parallel, fluorescence microscopy and laser speckle reflectometry were applied as two-dimensional reference modalities to image particle distribution and magnetically induced motion inside the sample, respectively. All three optical imaging modalities were in good agreement with each other. Thus, magnetomotive imaging using iron oxide nanoparticles as cellular contrast agents is a potential technique for enhanced visualization of selected cells in OCT.

Relation of joint spectral and time domain optical coherence tomography (jSTdOCT) and phase-resolved Doppler OCT

A variety of promising approaches for quantitative flow velocity measurement in OCT have been proposed in recent years. The question is: Which method gets the most precise flow velocity out of the interference signals detected. We have compared the promising joint spectral and time domain optical coherence tomography (jSTdOCT) and the commonly used phase-resolved Doppler OCT (DOCT) and describe the link between these two proven methods for OCT in the Fourier domain (FD OCT). First, we show that jSTdOCT can be significantly improved by calculating the center of gravity via an unbiased complex algorithm instead of detecting the maximum intensity signal of the broadened Doppler frequency spectrum. Secondly, we introduce a unified mathematical description for DOCT and jSTdOCT that differs only in one exponent and call it enhjSTdOCT. Third, we present that enhjSTdOCT has the potential to significantly reduce the noise of the velocity measurement by choosing an exponent depending on the transverse sample velocity component and the signal-to-noise ratio. EnhjSTdOCT is verified numerically and experimentally to find the optimal parameters for maximal velocity noise reduction.

[Photodynamic therapy of bladder cancer. A new option]

BACKGROUND

Bladder cancer (BCa) is the third most common tumor in Germany. Currently, resection therapy for superficial BCa (Ta, CIS) includes photodynamic diagnostics (PDD) using HEXVIX® for improved assessment of tumor spread. Trials using these photosensitizers for photodynamic therapy (PDT) showed only limited success. Especially low tissue penetration due to short-wave excitation was a limiting factor.

METHODS

This study which was funded by the German Research Foundation (DFG) examined the feasibility of the novel photosensitizer tetrahydroporphyrin-tetratosylate (THPTS) for PDT in a rat bladder cancer model.

RESULTS

As THPTS is very effectively excitable at a near infrared wavelength of 760 nm it is within the so-called phototherapeutic window and allows tissue penetration of up to 15 mm. Thus THPTS can also be used for PDT of larger, solid tumors as was previously demonstrated for other tumor entities. Therefore, effective treatment of even muscle-invasive bladder cancer (≥T2) may become an option using THPTS. In this current study the effectiveness and safety of THPTS-PDT was examined in an orthotopic bladder cancer rat model.

[Multidisciplinary health care needs of psychologically distressed cancer patients in a Comprehensive Cancer Center]

BACKGROUND AND OBJECTIVE

Considering the prolonged life-expectancies and the resulting demands that are placed on cancer patients and their relatives, the importance of specific counseling and support services including psycho-oncology, social services, nutritional, and exercise counseling has profoundly increased. The main focus of the current study was to evaluate the multidisciplinary health care needs of emotionally distressed cancer patients whoe were treated in a Comprehensive Cancer Center. METHODS AND STUDYGROUP: 831 out-patients were evaluated with regard to their psychological distress level and their multidisciplinary health care needs for specialist services of psycho-oncology, social services, nutritional, and exercise counseling using a tablet-PC assisted screening questionnaire. Separate analyses were completed for patients with and without psychological distress.

RESULTS

One third of the screened patients showed clinically relevant psychological distress. Health care needs for all specialist services were significantly greater among these patients compared to patients without psychological distress (all p-values < 0.005). The higher needs were foremost presented by the number of needed specialist services (p < 0.001): two thirds of the psychologically distressed patients demonstrated, besides the need for a psycho-oncological service, a need for two or three further specialist services, whereas among patients without psychological distress more than 70% showed a need for at most one specialist service.

CONCLUSION

Multidisciplinary health care needs of psychologically distressed cancer patients should be systematically addressed in a Comprehensive Cancer Center, and patients should be offered a coordinated and integrated health care program.

Nutrition, lifestyle factors, and mental health in adolescents and young adults living in Austria

BACKGROUND

Due to an alarming trend of overweight and obesity in children and adolescents, along with the sparse data on dietary habits and lifestyle factors, the present study aims to analyze the current nutritional behavior as well as the lifestyle and mental health of adolescents and young adults living in Austria.

MATERIALS AND METHODS

In this cross-sectional study, a total of 500 respondents (aged between 14 and 24 years) completed an anonymous questionnaire on nutrition behavior, mental health, and lifestyle factors by Internet survey.

RESULTS

Only 50% of the participants ate breakfast daily and 10% did not eat breakfast at all. About 47% of the respondents consumed milk and milk products daily. Furthermore, only 31% ate fruit and 21% ate vegetables at least once a day, and 46% ate fish seldom or never. Nearly 28% of young people liked to eat fast food twice or thrice a week and more, with males more often replacing a meal with a fast food product (36%) than females (21%). About 46% of the respondents engaged in physical activity only once a week (or more rarely). A fifth of our respondents (23%) spent more than 2 h a day using various social networks, with Facebook being the most popular social network among the respondents. Around 27% claimed to be smokers, with more female (33%) than male (20%) smoker. In terms of sleeping habits, 19% slept <6 h a day. Regarding well-being, 44% were more likely to feel stressed, 35% stated that they were tense, and 43% felt tired and listless. Eating together, physical activity, and sleep patterns showed positive effects on well-being, whereas higher consumption of fast food/snacks/soft drinks and alcoholic drinks/energy drinks was associated with relatively lower well-being.

CONCLUSIONS

Unhealthy eating habits, suboptimal physical activity, and smoking are still prominent in a sample of Austrian adolescents and young people. In addition, stress and tiredness are also relevant problems in this collective.