Muscular and neuronal control of voice production - forgotten findings, current concepts, and new developments

Voice production has been an area of interest in science since ancient times, and although advancing research has improved our understanding of the anatomy and function of the larynx, there is still little general consensus on these two topics. This review aims to outline the main developments in this field and highlight the areas where further research is needed. The most important hypotheses are presented and discussed highlighting the four main lines of research in the anatomy of the human larynx and their most important findings: (1) the arrangement of the muscle fibers of the thyroarytenoid muscle is not parallel to the vocal folds in the internal part (vocalis muscle), leading to altered properties during contraction; (2) the histological structure of the human vocal cords differs from other striated muscles; (3) there is a specialized type of heavy myosin chains in the larynx; and (4) the neuromuscular system of the larynx has specific structures that form the basis of an intrinsic laryngeal nervous system. These approaches are discussed in the context of current physiological models of vocal fold vibration, and new avenues of investigation are proposed.

A New Immortalized Human Lacrimal Gland Cell Line

The lacrimal gland is crucial for maintaining ocular health by producing the aqueous component of the tear film, which hydrates and nourishes the ocular surface. Decreased production of this component results in dry eye disease, a condition affecting over 250 million people worldwide. However, the scarcity of primary human material for studying its underlying mechanisms and the absence of a cell model for human lacrimal gland epithelial cells present significant challenges. Here, we describe the generation of immortalized human lacrimal gland cell lines through the introduction of an SV40 antigen. We successfully isolated and characterized three cell clones from a female lacrimal gland donor, confirming their epithelial identity through genomic and protein analyses, including PCR, RNAseq, immunofluorescence and cultivation in a 3D spheroid model. Our findings represent a significant advancement, providing improved accessibility to investigate the molecular pathogenesis mechanisms of dry eye disease and potential therapeutic interventions. We identified the expression of typical epithelial cell marker genes and demonstrated the cells' capability to form 2D cell sheets and 3D spheroids. This establishment of immortalized human lacrimal gland cells with epithelial characteristics holds promise for future comprehensive studies, contributing to a deeper understanding of dry eye disease and its cellular mechanisms.

Internal vascular anatomy of the human lacrimal gland: A protocol based on cadaver dissection and three-dimensional micro-computed tomography

PURPOSE

To evaluate the feasibility of studying the vascular supply of the orbital and palpebral lobes of the human lacrimal gland using micro-computed tomography (micro-CT) and microscopic dissection.

METHODS

The lacrimal gland artery of a fresh parasagittalized cadaver head (male, aged 76 years) was infused with a lead oxide-latex mixture near the occipital pole of the gland. The entire lacrimal gland was imaged using micro-CT and 3D cinematic rendering (CR) and then dissected under a surgical microscope.

RESULTS

Micro-CT and CR images showed well-demarcated internal vascular branches of the lacrimal artery and their distribution within the orbital and palpebral lobes. The entire course of the artery and its branches could be visualized by CR and microscopic dissection, with the former showing better spatial orientation and finer branching. The main artery runs along the free edge of the aponeurosis of the levator palpebrae superior muscle and lies in the isthmus portion of the gland (between the orbital and palpebral lobes). The branches of the main lacrimal artery include one branch to the orbital adipose tissue just before entering the gland, two branches to the orbital lobe (medial and lateral), and two branches to the palpebral lobe (medial and lateral). The main artery terminates as palpebral and orbital lobe branches in the lateral half of the lacrimal gland.

CONCLUSION

Latex and contrast-enhanced micro-CT is very well suited to visualize the vascular anatomy of the lacrimal artery within the gland. A large number of lacrimal gland examinations using the method presented here are required to demonstrate and understand the variability of the vascular anatomy of the human lacrimal gland.

Historical Profiling of Dry Eye Patients - Potential Trigger Factors and Comorbidities

PURPOSE

Dry eye syndrome (DES) is one of the most common diseases of the ocular surface. Affected persons suffer from different subjective complaints, with sometimes severe impairment in the quality of life. The aetiology and pathogenesis are multifactorial, multifaceted, and not yet fully understood. The present study is intended to provide deeper insights into possible triggering factors and correlating comorbidities.

MATERIALS AND METHODS

In German ophthalmological practices, 306 persons (174 women, 132 men, age: 18 - 87 years) were interviewed by questionnaire on concomitant diseases and possible further triggering factors. DES was diagnosed by an ophthalmologist in 170 cases. The statistical comparative analysis between persons with and without DES was carried out using the chi-squared test (SPSS statistical software).

RESULTS

DES occurred with significantly (p < 0.05) increased frequency in women over 40 years of age, as well as in persons exposed to screen work, air conditioning, persons with chronic ocular inflammation, myomas (hysterectomy), dry skin, arterial hypertonicity in need of medication, cardiac arrhythmias, fatty liver, gastric ulcer, appendicitis, cholecystectomy, depression, hyperlipidaemia, hyperuricaemia, osteoporosis, and nephrolithiasis.

CONCLUSION

Some of the known comorbidities and DES risk factors, e.g., computer work or depression, were confirmed. In contrast, the higher prevalence of hyperlipidaemia, hyperuricaemia, osteoporosis, nephrolithiasis, and fibroids among DES patients has not previously been reported. Additional studies should be performed on causal connections between DES and specific comorbidities.

Inverse identification of region-specific hyperelastic material parameters for human brain tissue

The identification of material parameters accurately describing the region-dependent mechanical behavior of human brain tissue is crucial for computational models used to assist, e.g., the development of safety equipment like helmets or the planning and execution of brain surgery. While the division of the human brain into different anatomical regions is well established, knowledge about regions with distinct mechanical properties remains limited. Here, we establish an inverse parameter identification scheme using a hyperelastic Ogden model and experimental data from multi-modal testing of tissue from 19 anatomical human brain regions to identify mechanically distinct regions and provide the corresponding material parameters. We assign the 19 anatomical regions to nine governing regions based on similar parameters and microstructures. Statistical analyses confirm differences between the regions and indicate that at least the corpus callosum and the corona radiata should be assigned different material parameters in computational models of the human brain. We provide a total of four parameter sets based on the two initial Poisson's ratios of 0.45 and 0.49 as well as the pre- and unconditioned experimental responses, respectively. Our results highlight the close interrelation between the Poisson's ratio and the remaining model parameters. The identified parameters will contribute to more precise computational models enabling spatially resolved predictions of the stress and strain states in human brains under complex mechanical loading conditions.

New insights into lacrimal gland anatomy using 7T MRI and electron microscopy: Relevance for lacrimal gland targeted therapies and bioengineering

PURPOSE

To study the tissue architecture, isthmus (connection between two lobes) of the lacrimal gland using preclinical 7T MRI in combination with histology and electron microscopy.

METHODS

Ten lacrimal glands from Caucasian body donors (mean age 78.7 years) were studied using 7T-MRI (N = 5; scanned at 75-μm intervals), histology, and electron microscopy (N = 5) and 3D cinematic rendering (CR) techniques.

RESULTS

3D CR images showed uniform-sized lobules (widest lobule diameter, 1.68 ± 0.19 mm in orbital lobe, 1.68 ± 0.17 mm in palpebral lobe) in both lobes, separated by septae (size, 0.29 ± 0.09 mm). The internal framework of the gland resembled a honeycoomb pattern. In CR and histology, the isthmus contained glandular acini, large blood vessels, nerves, and no more than two ducts having a tortuous course towards the conjunctival surface. On assigning a color display to the rendered lacrimal gland, all glands showed a blood vessel originating from the main lacrimal artery just 5 mm beyond the hilum and making it course to the palpebral lobe via isthmus. The distance between the conjunctiva and the central substance of the orbital and palpebral lobe was 9.4 ± 0.2 mm and 2.8 ± 0.7 mm, respectively. Electron microscopy of the palpebral lobe revealed compact subepithelial layer in the overlying conjunctiva, followed by loosely scattered collagen bundles that contained the gland lobules.

CONCLUSION

3D-CR can be used to study the lacrimal gland microstructure, help fabricate a 3D scaffold for lacrimal gland bioprinting, and serve as guide for transconjunctival lacrimal gland targeted therapies i.e., 2.9 & 9 mm long needle to reach the orbital and palpebral lobe center, respectively in normal-size glands.

The chemicals between us-First results of the cluster analyses on anatomy embalming procedures in the German-speaking countries

Hands-on courses utilizing preserved human tissues for educational training offer an important pathway to acquire basic anatomical knowledge. Owing to the reevaluation of formaldehyde limits by the European Commission, a joint approach was chosen by the German-speaking anatomies in Europe (Germany, Austria, Switzerland) to find commonalities among embalming protocols and infrastructure. A survey comprising 537 items was circulated to all anatomies in German-speaking Europe. Clusters were established for "ethanol"-, formaldehyde-based ("FA"), and "other" embalming procedures, depending on the chemicals considered the most relevant for each protocol. The logistical framework, volumes of chemicals, and infrastructure were found to be highly diverse between the groups and protocols. Formaldehyde quantities deployed per annum were three-fold higher in the "FA" (223 L/a) compared to the "ethanol" (71.0 L/a) group, but not for "other" (97.8 L/a), though the volumes injected per body were similar. "FA" was strongly related to table-borne air ventilation and total fixative volumes ≤1000 L. "Ethanol" was strongly related to total fixative volumes >1000 L, ceiling- and floor-borne air ventilation, and explosion-proof facilities. Air ventilation was found to be installed symmetrically in the mortuary and dissection facilities. Certain predictors exist for the interplay between the embalming used in a given infrastructure and technical measures. The here-established cluster analysis may serve as decision supportive tool when considering altering embalming protocols or establishing joint protocols between institutions, following a best practice approach to cater toward best-suited tissue characteristics for educational purposes, while simultaneously addressing future demands on exposure limits.

AB0113 A MINIMAL-INVASIVE METHOD TO RETRIEVE AND IDENTIFY ENTHESEAL TISSUE FROM PSORIATIC ARTHRITIS PATIENTS

Background

Enthesitis represents a hallmark feature of spondyloarthritis, including psoriatic arthritis (PsA).1 So far, most of the data on enthesitis in PsA are based on clinical assessment of tenderness as well as MRI or ultrasound examinations.2 These approaches, however, do not allow molecular analysis of entheses, which will require acquisition of entheseal tissue. Up today, it is unknown, which entheseal structure in humans would qualify for a feasible biopsy and how correct sampling of entheseal structures could be ascertained within such biopsy material. These technical challenges have led to substantial lack of knowledge on human entheseal tissues.

Objectives

To establish a minimally invasive biopsy technique of human entheses for the analysis of entheseal tissue in patients with PsA.

Methods

Human cadavers were used for establishing the technique to retrieve tissue from the lateral humeral epicondyle enthesis (cadaveric biopsies). After biopsy, the entire entheses was surgically resected (cadaveric resections). Biopsies and resections were assessed by label-free second-harmonic-generation (SHG) microscopy. The same biopsy technique was then applied in PsA patients with subsequent definition of entheseal tissue by SHG.

Results

Entheseal biopsies were performed in five cadavers and allowed the retrieval of entheseal tissue, validated by analysis of the resection material. Thus, microscopy of biopsy and resection sections allowed differentiation of entheseal, tendon and muscle tissue by SHG and definition of specific intensity thresholds for entheseal tissue. The same method was then successfully applied to 10 PsA patients. Hence, the fraction of entheseal tissue within the PsA biopsy specimens was high (65%) and comparable to the fraction retrieved in cadaveric biospies (68%) as assessed by SHG microscopy.

Conclusion

Entheseal biopsy of the tendon plate of the lateral epicondyle is feasible in PsA patients allowing reliable retrieval of entheseal tissue and its identification by SHG microscopy.

References

[1]Schett, G, Lories D, D´Agostino MA, Elewaut E, Kirkham B, Soriano ER, McGonagle D. Enthesitis: from pathophysiology to treatment Nat Rev Rheumatol 2017 Nov 21;13(12):731-741.

[2]Groves C, Chandramohan M, Chew NS, et al. Clinical Examination, Ultrasound and MRI Imaging of The Painful Elbow in Psoriatic Arthritis and Rheumatoid Arthritis: Which is Better, Ultrasound or MR, for Imaging Enthesitis? Rheumatol Ther 2017;4:71-84.

Disclosure of Interests

None declared

Unraveling the Local Relation Between Tissue Composition and Human Brain Mechanics Through Machine Learning

The regional mechanical properties of brain tissue are not only key in the context of brain injury and its vulnerability towards mechanical loads, but also affect the behavior and functionality of brain cells. Due to the extremely soft nature of brain tissue, its mechanical characterization is challenging. The response to loading depends on length and time scales and is characterized by nonlinearity, compression-tension asymmetry, conditioning, and stress relaxation. In addition, the regional heterogeneity-both in mechanics and microstructure-complicates the comprehensive understanding of local tissue properties and its relation to the underlying microstructure. Here, we combine large-strain biomechanical tests with enzyme-linked immunosorbent assays (ELISA) and develop an extended type of constitutive artificial neural networks (CANNs) that can account for viscoelastic effects. We show that our viscoelastic constitutive artificial neural network is able to describe the tissue response in different brain regions and quantify the relevance of different cellular and extracellular components for time-independent (nonlinearity, compression-tension-asymmetry) and time-dependent (hysteresis, conditioning, stress relaxation) tissue mechanics, respectively. Our results suggest that the content of the extracellular matrix protein fibronectin is highly relevant for both the quasi-elastic behavior and viscoelastic effects of brain tissue. While the quasi-elastic response seems to be largely controlled by extracellular matrix proteins from the basement membrane, cellular components have a higher relevance for the viscoelastic response. Our findings advance our understanding of microstructure - mechanics relations in human brain tissue and are valuable to further advance predictive material models for finite element simulations or to design biomaterials for tissue engineering and 3D printing applications.

Polytetrafluoroethylene (PTFE) suture vs fiberwire and polypropylene in flexor tendon repair

BACKGROUND

In this study, we evaluate the value of novel suture material based on monofilamentous-extruded polyfluoroethylene (PTFE) compared to polypropylene (PPL) and Fiberwire (FW).

MATERIALS AND METHODS

60 flexor tendons were harvested from fresh cadaveric upper extremities. 4-0 sutures strands were used in the PPL, FW and PTFE group. Knotting properties and mechanical characteristics of the suture materials were evaluated. A 4-strand locked cruciate (Adelaide) or a 6-strand (M-Tang) suture technique was applied as core sutures for a tendon repair. Two-way ANOVA tests were performed with the Bonferroni correction.

RESULTS

Stable knotting was achieved with 5 throws with the PPL material, 7 throws for FW and 9 throws for PTFE. In the PPL group, linear tensile strength was 45.92 ± 12.53 N, in the FW group 80.11 ± 18.34 N and in the PTFE group 76.16 ± 29.10 N. FW and PTFE are significantly stronger than PPL but show no significant difference among each other. Similar results were obtained in the subgroup comparisons for different repair techniques. The Adelaide and the M-Tang knotting technique showed no significant difference.

CONCLUSION

Fiberwire showed superior handling and knotting properties in comparison to PTFE. However, PTFE allows easier approximation of the stumps. In both, M-Tang and Adelaide repairs, PTFE was equal to FW in terms of repair strength. Both PTFE and FW provide for a robust tendon repair so that early active motion regimens for rehabilitation can be applied.

Complex mechanical behavior of human articular cartilage and hydrogels for cartilage repair

The mechanical behavior of cartilage tissue plays a crucial role in physiological mechanotransduction processes of chondrocytes and pathological changes like osteoarthritis. Therefore, intensive research activities focus on the identification of implant substitute materials that mechanically mimic the cartilage extracellular matrix. This, however, requires a thorough understanding of the complex mechanical behavior of both native cartilage and potential substitute materials to treat cartilage lesions. Here, we perform complex multi-modal mechanical analyses of human articular cartilage and two surrogate materials, commercially available ChondroFiller_liquid, and oxidized alginate-gelatin (ADA-GEL) hydrogels. We show that all materials exhibit nonlinearity and compression-tension asymmetry. However, while hyaline cartilage yields higher stresses in tension than in compression, ChondroFiller^liquid and ADA-GEL exhibit the opposite trend. These characteristics can be attributed to the materials' underlying microstructure: Both cartilage and ChondroFiller^liquid contain fibrillar components, but the latter constitutes a bi-phasic structure, where the 60% nonfibrillar hydrogel proportion dominates the mechanical response. Of all materials, ChondroFiller^liquid shows the most pronounced viscous effects. The present study provides important insights into the microstructure-property relationship of cartilage substitute materials, with vital implications for mechanically-driven material design in cartilage engineering. In addition, we provide a data set to create mechanical simulation models in the future.

[Is there a new salivary gland? - Rather not!]

In October 2020, the lay press, but also some medical journals and websites reported the putative discovery of a new salivary gland in the nasopharynx based on prostate-specific membrane antigen positron emission tomography computed tomography (PSMA-PET/CT) examinations. As an interdisciplinary group from the fields of anatomy, pathology, nuclear medicine and otorhinolaryngology, we come to the view that an accumulation of minor salivary glands has been described here. Minor salivary glands in the nasopharynx and in the peritubar region have been described at least since 1866. The current description in PSMA-PET/CT does not justify the definition of a new, independent salivary gland. The PSMA-PET/CT could, however, be suitable to better protect salivary glands in the nasopharynx when planning radiation therapy. This should be evaluated in clinical trials.

Examining the role of the surfactant family member SFTA3 in interneuron specification

The transcription factor NKX2.1, expressed at high levels in the medial ganglionic eminence (MGE), is a master regulator of cortical interneuron progenitor development. To identify gene candidates with expression profiles similar to NKX2.1, previous transcriptome analysis of human embryonic stem cell (hESC)-derived MGE-like progenitors revealed SFTA3 as the strongest candidate. Quantitative real-time PCR analysis of hESC-derived NKX2.1-positive progenitors and transcriptome data available from the Allen Institute for Brain Science revealed comparable expression patterns for NKX2.1 and SFTA3 during interneuron differentiation in vitro and demonstrated high SFTA3 expression in the human MGE. Although SFTA3 has been well studied in the lung, the possible role of this surfactant protein in the MGE during embryonic development remains unexamined. To determine if SFTA3 plays a role in MGE specification, SFTA3-/- and NKX2.1 -/- hESC lines were generated using custom designed CRISPRs. We show that NKX2.1 KOs have a significantly diminished capacity to differentiate into MGE interneuron subtypes. SFTA3 KOs also demonstrated a somewhat reduced ability to differentiate down the MGE-like lineage, although not as severe relative to NKX2.1 deficiency. These results suggest NKX2.1 and SFTA3 are co-regulated genes, and that deletion of SFTA3 does not lead to a major change in the specification of MGE derivatives.

Evaluation of surfactant proteins A, B, C, and D in articular cartilage, synovial membrane and synovial fluid of healthy as well as patients with osteoarthritis and rheumatoid arthritis

OBJECTIVE

Surfactant Proteins (SPs) are well known from lung and form, along with phospholipids, a surface-active-layer at the liquid-air-interface of the alveolar lining. They play a major protective role by lowering surface tension, activating innate and adaptive immune defense at the lung mucosal interface, especially during infection. We analyzed the regulation of SPs in human and mouse articular chondrocytes, synoviocytes, and synovial fluid under healthy and inflammatory conditions, as well as in tissues of patients suffering from osteoarthritis and rheumatoid arthritis.

METHODS

Immunohistochemistry, RT-PCR, qRT-PCR, ELISA, Western blotting were performed in cell cultures and tissue samples to determine localization, regulation, and concentration of SPs.

RESULTS

All four SPs, were expressed by healthy human and mouse articular chondrocytes and synoviocytes and were also present in synovial fluid. Treatment with inflammatory mediators like IL-1β and TNF-α led to short-term upregulation of individual SPs in vitro. In tissues from patients with osteoarthritis and rheumatoid arthritis, protein levels of all four SPs increased significantly compared to the controls used.

CONCLUSION

These results show the distribution and amount of SPs in tissues of articular joints. They are produced by chondrocytes and synoviocytes and occur in measurable amounts in synovial fluid. All four SPs seem to be differently regulated under pathologic conditions. Their physiological functions in lowering surface tension and immune defense need further elucidation and make them potential candidates for therapeutic intervention.

SFTA3 - a novel surfactant protein of the ocular surface and its role in corneal wound healing and tear film surface tension

The study aimed to characterize the expression and function of SFTA3 at the ocular surface and in tears. Ocular tissues, conjunctival (HCjE) and human corneal (HCE) epithelial cell lines as well as tearfilm of patients suffering from different forms of dry eye disease (DED) were analyzed by means of RT-PCR, western blot, immunohistochemistry, and ELISA. A possible role of recombinant SFTA3 in corneal wound healing was investigated performing in vitro scratch assays. Tear film regulatory properties were analyzed with the spinning drop method and the regulation of SFTA3 transcripts was studied in HCE and HCjE after incubation with proinflammatory cytokines as well as typical ocular pathogens by real-time RT-PCR and ELISA. The results reveal that human ocular tissue as well as tears of healthy volunteers express SFTA3 whereas tears from patients with DED showed significantly increased SFTA3 levels. In vitro wounding of HCE cell cultures that had been treated with recombinant SFTA3 demonstrated a significantly increased wound closure rate and rSFTA3 reduced the surface tension of tear fluid. The results indicate that SFTA3 at the ocular surface seemed to be involved in wound healing and the reduction of surface tension.

[Anatomy and physiology of the nasolacrimal ducts]

Ophthalmologists and interventional radiologists are not the only professionals for whom diseases of the efferent tear duct system occupy centre stage; this applies also to ENT specialists involving endonasal conservative or surgical treatment. On the basis of current knowledge and taking account of results yielded by own research in recent years and of clinical aspects, we here give an overview of basic knowledge on the anatomy and physiology of the nasolacrimal system. In doing so functional aspects regarding tear transport as well as embryological and pathophysiological issues are integrated.

Palate Lung Nasal Clone (PLUNC), a Novel Protein of the Tear Film: Three-Dimensional Structure, Immune Activation, and Involvement in Dry Eye Disease (DED)

PURPOSE

Palate Lung Nasal Clone (PLUNC) is a hydrophobic protein belonging to the family of surfactant proteins that is involved in fluid balance regulation of the lung. Moreover, it is known to directly act against gram-negative bacteria. The purpose of this study was to investigate the possible expression and antimicrobial role of PLUNC at the healthy ocular surface and in tears of patients suffering from dry eye disease (DED).

METHODS

Bioinformatics and biochemical and immunologic methods were combined to elucidate the structure and function of PLUNC at the ocular surface. Tissue-specific localization was performed by using immunohistochemistry. The PLUNC levels in tear samples from non-Sjögren's DED patients with moderate dry eye suffering either from hyperevaporation or tear deficiency were analyzed by ELISA and compared with tears from healthy volunteers.

RESULTS

Palate Lung Nasal Clone is expressed under healthy conditions at the ocular surface and secreted into the tear film. Protein modeling studies and molecular dynamics simulations performed indicated surface activity of PLUNC. In vitro experiments revealed that proinflammatory cytokines and bacterial supernatants have only a slight effect on the expression of PLUNC in HCE and HCjE cell lines. In tears from DED patients, the PLUNC concentration is significantly increased (7-fold in evaporative dry eye tears and 17-fold in tears from patients with tear deficiency) compared with healthy subjects.

CONCLUSIONS

The results show that PLUNC is a protein of the tear film and suggest that it plays a role in fluid balance and surface tension regulation at the ocular surface.

Somatostatin supports corneal wound healing in vivo

PURPOSE

To evaluate the influence of somatostatin (SST) and its analog octreotid (Oct) on corneal wound healing processes.

METHODS

The wound healing rate in C57BL/6 mice eyes under SST and Oct treatment was analyzed using an alkali-induced corneal wounding model. Effects of SST and Oct on cell proliferation, migration and quantified protein expression of vascular endothelial growth factor (VEGF) on human corneal epithelial cells (HCE, cell line) were evaluated by means of electric cell-substrate impedance sensing, scratch migration assays and ELISA. ERK1/2 and p38 phosphorylation was investigated by semi-quantitative western blot analysis.

RESULTS

Ten nanograms per microliters of SST significantly accelerated the wound closure rate of corneal defects in vivo. SST and Oct had no influence on HCE cell proliferation and migration and did not activate ERK1/2 or p38 signaling in HCE cells. However, there was increased VEGF protein expression in cytosolic proteins and medium supernatants of HCE upon Oct stimulation for 24h. One and 10ng/ml Oct led to a 2.5-fold and 100ng/ml Oct to a 4-fold upregulation of VEGF protein expression.

CONCLUSION

The data implicate that SST promotes corneal wound healing in a mouse model. However, using a HCE cell line in vitro, the wound healing mechanism does not seem to be supported by proliferation and migration processes or by activation of ERK1/2 and p38 signaling pathways. Other possible mechanisms could be the activation of other pathways and the induction of growth factors such as VEGF that modulate the observed corneal wound healing process.

Strategies against burnout and anxiety in medical education--implementation and evaluation of a new course on relaxation techniques (Relacs) for medical students

Burnout and stress-related mental disorders (depression, anxiety) occur in medical students and physicians with a significantly higher prevalence than in the general population. At the same time, the learning of coping mechanisms against stress is still not an integral part of medical education. In this pilot study we developed an elective course for learning relaxation techniques and examined the condition of the students before and after the course. 42 students participated in the semester courses in 2012 and 2013 as well as in a survey at the start and end of each course. The students were instructed in autogenic training (AT) and progressive muscle relaxation according to Jacobsen (PMR) with the goal of independent and regular exercising. At the beginning and the end of the semester/course the students were interviewed using standardized, validated questionnaires on burnout (BOSS-II) and anxiety (STAI-G), depression (BDI), quality of life (SF-12) and sense of coherence (SOC-L9). We compared the results of our students participating in Relacs with results from eight semester medical students (n = 88), assessed with the same questionnaires at similar points of time within their semester. Participating students showed a significant decline in cognitive and emotional burnout stress and in trait anxiety. Furthermore, they showed a reduction in state anxiety and a conspicuous decrease in mean depression. The sense of coherence increased at the same time. A comparative cohort of medical students of 8^th semester students, showed lower values for the specified measurement parameters at the beginning, but showed no progressive changes. Our course introducing AT and PMR led to a significant reduction of burnout and anxiety within the participating group of medical students. Even the course attendance for just one semester resulted in significant improvements in the evaluated parameters in contrast to those students who did not attend the course.

The novel surfactant protein SP-H enhances the phagocytosis efficiency of macrophage-like cell lines U937 and MH-S

Background

Surfactant proteins (SP) secreted by alveolar type 2 cells, play an essential role in maintaining the air-liquid barrier of the lung and are also involved in the opsonisation and clearance of bacteria by phagocytes. We have recently described a novel surfactant protein, SP-H (SFTA3). Expression of SP-H was earlier demonstrated to be upregulated by LPS and negatively regulated by IL-1β and IL-23 in vitro. The influence of SP-H on phagocytosis was measured using a murine and a human phagocytic cell line and fluorescent latex beads.

Findings

SP-H markedly increases phagocytosis in vitro in the murine-derived alveolar macrophage cell lines MH-S and in human-derived differentiated U937 cells.

Conclusion

It can be assumed that SP-H is involved in regulating phagocytic activity of macrophages. SP-H is a new player in pulmonary host defence.

SFTA3, a novel protein of the lung: three-dimensional structure, characterisation and immune activation

The lung constantly interacts with numerous pathogens. Thus, complex local immune defence mechanisms are essential to recognise and dispose of these intruders. This work describes the detection, characterisation and three-dimensional structure of a novel protein of the lung (surfactant-associated protein 3 (SFTA3/SP-H)) with putative immunological features. Bioinformatics, biochemical and immunological methods were combined to elucidate the structure and function of SFTA3. The tissue-specific detection and characterisation was performed by using electron microscopy as well as fluorescence imaging. Three-dimensional structure generation and analysis led to the development of specific antibodies and, as a consequence, to the localisation of a novel protein in human lung under consideration of cystic fibrosis, asthma and sepsis. In vitro experiments revealed that lipopolysaccharide induces expression of SFTA3 in the human lung alveolar type II cell line A549. By contrast, the inflammatory cytokines interleukin (IL)-1β and IL-23 inhibit expression of SFTA3 in A549. Sequence- and structure-based prediction analysis indicated that the novel protein is likely to belong to the family of lung surfactant proteins. The results suggest that SFTA3 is an immunoregulatory protein of the lung with relevant protective functions during inflammation at the mucosal sites.

Articular cartilage chondrocytes express aromatase and use enzymes involved in estrogen metabolism

Introduction

Sex hormones, especially estrogens, have been implicated in articular cartilage metabolism and the pathogenesis of postmenopausal osteoarthritis. The conversion by aromatase (CYP19A1) of androstenedione into estrone (E1) and of testosterone into 17β-estradiol (E2) plays a key role in the endogenous synthesis of estrogens in tissue.

Methods

We analyzed the expression of aromatase (CYP19A1) in immortalized C-28/I2 and T/C-28a2 chondrocytes, as well as in cultured primary human articular chondrocytes and human articular cartilage tissue, by means of RT-PCR, Western blotting and immunohistochemistry. By means of quantitative RT-PCR and enzyme-linked immunosorbent assay, we also determined whether the aromatase inhibitor letrozole influences estrogen metabolism of cultured chondrocytes in immortalized C-28/I2 chondrocytes.

Results

Aromatase mRNA was detected in both immortalized chondrocyte cell lines, in cultured primary human chondrocytes, and in human articular cartilage tissue. By means of Western blot analysis, aromatase was detected at the protein level in articular cartilage taken from various patients of both sexes and different ages. Cultured primary human articular chondrocytes, C-28/I2 and T/C-28a2, and human articular cartilage tissue reacted with antibodies for aromatase. Incubation of C-28/I2 chondrocytes with 10⁻¹¹ M to 10⁻⁷ M letrozole as an aromatase inhibitor revealed significantly increased amounts of the mRNAs of the enzyme cytochrome P4501A1 (CYP1A1), which is involved in the catagen estrogen metabolism, and of the estrogen receptors ER-α and ER-β. Concomitantly, synthesis of estrone (E1) was significantly downregulated after incubation with letrozole.

Conclusions

We demonstrate that human articular cartilage expresses aromatase at the mRNA and protein levels. Blocking of estrone synthesis by the aromatase inhibitor letrozole is counteracted by an increase in ER-α and ER-β. In addition, CYP1A1, an enzyme involved in catabolic estrogen metabolism, is upregulated. This suggests that articular chondrocytes use ERs functionally. The role of endogenous synthesized estrogens in articular cartilage health remains to be elucidated.

The detection of surfactant proteins A, B, C and D in the human brain and their regulation in cerebral infarction, autoimmune conditions and infections of the CNS

Surfactant proteins (SP) have been studied intensively in the respiratory system. Surfactant protein A and surfactant protein D are proteins belonging to the family of collectins each playing a major role in the innate immune system. The ability of surfactant protein A and surfactant protein D to bind various pathogens and facilitate their elimination has been described in a vast number of studies. Surfactant proteins are very important in modulating the host's inflammatory response and participate in the clearance of apoptotic cells. Surfactant protein B and surfactant protein C are proteins responsible for lowering the surface tension in the lungs. The aim of this study was an investigation of expression of surfactant proteins in the central nervous system to assess their specific distribution patterns. The second aim was to quantify surfactant proteins in cerebrospinal fluid of healthy subjects compared to patients suffering from different neuropathologies. The expression of mRNA for the surfactant proteins was analyzed with RT-PCR done with samples from different parts of the human brain. The production of the surfactant proteins in the brain was verified using immunohistochemistry and Western blot. The concentrations of the surfactant proteins in cerebrospinal fluid from healthy subjects and patients suffering from neuropathologic conditions were quantified using ELISA. Our results revealed that surfactant proteins are present in the central nervous system and that the concentrations of one or more surfactant proteins in healthy subjects differed significantly from those of patients affected by central autoimmune processes, CNS infections or cerebral infarction. Based on the localization of the surfactant proteins in the brain, their different levels in normal versus pathologic samples of cerebrospinal fluid and their well-known functions in the lungs, it appears that the surfactant proteins may play roles in host defense of the brain, facilitation of cerebrospinal fluid secretion and maintenance of the latter's rheological properties.

Effects of keratin and lung surfactant proteins on the surface activity of meibomian lipids

PURPOSE

In vitro studies indicate that surface tension and surface viscosity of the tear film lipid layer (TFLL) are governed by interactions between meibomian lipids and proteins from the aqueous layer. The role of minor tear proteins with strong lipophilic properties or those correlated with pathological states is still unknown. The discovery of lung surfactant proteins (SPs) in tears and keratin in normal and abnormal meibomian gland excretions warrants investigation into their effects on the surface activity of meibomian lipid films.

METHODS

Commercial keratin and bovine lung SPs were used in vitro to assess the surface pressure of meibomian lipid films using a Langmuir trough.

RESULTS

The pressure-area profiles of meibomian lipid films seeded with SPs (2.5 μL; 0.1 μg) demonstrated hybrid characteristics between meibomian lipid films alone and SPs alone but reached much higher maximum surface pressures (approximately 30 vs. 24 mN/m). Microscopically, the appearance of meibomian lipid films was not altered by SPs. Maximum surface pressure of meibomian films premixed with keratin was much higher than meibum alone. The pressure-area isocycles appeared more like those of meibomian lipids with a low concentration of protein and more like pure keratin films at a high concentration.

CONCLUSIONS

The data strongly indicate that SPs and keratin likely interact with the TFLL. SPs are likely to act as strong surfactants and to reduce the surface tension of the lipid layer. Excess concentrations of keratin as identified in patients with meibomian gland dysfunction could disrupt the normal structure of the meibomian lipid film.

Staphylococcus aureus and Pseudomonas aeruginosa express and secrete human surfactant proteins

Surfactant proteins (SP), originally known from human lung surfactant, are essential to proper respiratory function in that they lower the surface tension of the alveoli. They are also important components of the innate immune system. The functional significance of these proteins is currently reflected by a very large and growing number of publications. The objective goal of this study was to elucidate whether Staphylococcus aureus and Pseudomonas aeruginosa is able to express surfactant proteins. 10 different strains of S. aureus and P. aeruginosa were analyzed by means of RT-PCR, Western blot analysis, ELISA, immunofluorescence microscopy and immunoelectron microscopy. The unexpected and surprising finding revealed in this study is that different strains of S. aureus and P. aeruginosa express and secrete proteins that react with currently commercially available antibodies to known human surfactant proteins. Our results strongly suggest that the bacteria are either able to express ‘human-like’ surfactant proteins on their own or that commercially available primers and antibodies to human surfactant proteins detect identical bacterial proteins and genes. The results may reflect the existence of a new group of bacterial surfactant proteins and DNA currently lacking in the relevant sequence and structure databases. At any rate, our knowledge of human surfactant proteins obtained from immunological and molecular biological studies may have been falsified by the presence of bacterial proteins and DNA and therefore requires critical reassessment.

Detection of Surfactant Proteins A, B, C, and D in Human Nasal Mucosa and Their Regulation in Chronic Rhinosinusitis with Polyps

Backround

The nasal mucosa is characterized by a multirow high prismatic ciliated epithelium representing the first barrier of the immune defense system against microbial and other environmental pathogenic influences. A number of nonspecific defense mechanisms, including the presence of lactoferrin, peroxidases, proteases, interferons, and lysozymes in nasal secretions, act to counter inflammatory processes. The surfactant proteins (SPs) known from the lungs are important components of the innate immune system. They also influence the rheology of fluids and reduce the surface tension of gas–fluid interphases. The objective of this study was to investigate the protein expression of all four SPs. A specific aim was detection and characterization of SP-C, which had previously not been confirmed in human nasal mucosa.

Methods

The expression of mRNA for SP-A, -B, -C and -D was investigated using reverse transcriptase polymerase chain reaction on samples of both healthy nasal mucosa and nasal mucosa altered by inflammatory processes (allergic rhinitis and chronic rhinosinusitis). The distribution of all four proteins was determined with monoclonal antibodies using Western blot analysis as well as immunohistochemical methods.

Results

The results show that all four SPs, including SP-C not detected before this, are nasal mucosa components. A shift was also observed in the expression behavior of the SP-A, -B, and -D in nasal mucosa with inflammatory changes.

Conclusion

Based on these results, SPs appear to have an important function in immunologic and rheological process of the nasal mucosa and support the prospective therapeutic use of liposomal nasal sprays.

Schirmer strip vs. capillary tube method: non-invasive methods of obtaining proteins from tear fluid

Human tear fluid is a complex mixture containing over 500 solute proteins, lipids, electrolytes, mucins, metabolites, hormones and desquamated epithelial cells as well as foreign substances from the ambient air. Little is known to date about the function of most tear components. The efficient and gentle collection of tear fluid facilitates closer investigation of these matters. The objective of the present paper was to compare two commonly used methods of obtaining tear fluid, the capillary tube and Schirmer strip methods, in terms of usefulness in molecular biological investigation of tear film. The comparative protein identification methods Bradford and Western Blot were used in the analyses to this end. The surfactant proteins (SP) A-D recently described as present on the eye surface were selected as the model proteins. Both methods feature sufficient uptake efficiency for proteins in or extraction from the sampling means used (capillary tube/Schirmer strip). The total protein concentration can be determined and the proteins in the tears can be detected - besides the hydrophilic SP-A and D also the non-water-soluble proteins of smaller size such as SP-B and C. Thus both methods afford a suitable basis for comparative analysis of the physiological processes in the tear fluid of healthy and diseased subjects. On the whole, the Schirmer strip has several advantages over the capillary tube.

"SP-G", a putative new surfactant protein--tissue localization and 3D structure

Surfactant proteins (SP) are well known from human lung. These proteins assist the formation of a monolayer of surface-active phospholipids at the liquid-air interface of the alveolar lining, play a major role in lowering the surface tension of interfaces, and have functions in innate and adaptive immune defense. During recent years it became obvious that SPs are also part of other tissues and fluids such as tear fluid, gingiva, saliva, the nasolacrimal system, and kidney. Recently, a putative new surfactant protein (SFTA2 or SP-G) was identified, which has no sequence or structural identity to the already know surfactant proteins. In this work, computational chemistry and molecular-biological methods were combined to localize and characterize SP-G. With the help of a protein structure model, specific antibodies were obtained which allowed the detection of SP-G not only on mRNA but also on protein level. The localization of this protein in different human tissues, sequence based prediction tools for posttranslational modifications and molecular dynamic simulations reveal that SP-G has physicochemical properties similar to the already known surfactant proteins B and C. This includes also the possibility of interactions with lipid systems and with that, a potential surface-regulatory feature of SP-G. In conclusion, the results indicate SP-G as a new surfactant protein which represents an until now unknown surfactant protein class.

Characterization of the mucocutaneous junction of the human eyelid margin and meibomian glands with different biomarkers

PURPOSE

To investigate the morphology of the human eyelid margin and the presence of different cytokeratins, mucins and stem cell markers within the skin epithelium, mucocutaneous junction (MCJ) and palpebral conjunctiva.

METHODS

Eyelids of body donors were investigated histologically and ultrastructurally as well as by immunohistochemical methods using antibodies to cytokeratins 1, 4, 7, 8, 10, 13, 14, 15, and 19; mucins MUC1, MUC4, and MUC5AC and potential stem cell markers K15, BCRP/ABCG2, integrin β1, and N-cadherin.

RESULTS

The expression pattern of cytokeratins, mucins and stem cell markers varied across the different epithelia of the human eyelid. Within the MCJ, CK7, 15 and 19 were absent, whereas the epithelium reacted positive to antibodies to CK1, 4, 8, 10, 13 and 14. Reactivity was also observed for MUC1 and MUC4, but not for MUC5AC. No reactivity was determined for K15, BCRP/ABCG2 and integrin β1 in the area of the MCJ epithelium but a strong reactivity was present for N-cadherin.

CONCLUSIONS

The present immunohistochemical findings lead to a better characterization of the MCJ. Additionally, the knowledge of distribution of biomarkers like cytokeratins, mucins and stem cells can be useful in the investigation of MCJ disturbances which occur in several disorders of the meibomian glands and the lid epithelium in the course of dry eye syndrome and especially meibomian gland dysfunction.

Expression profile of aquaporins in human nasolacrimal duct epithelium

PURPOSE

To determine whether the epithelium of the human nasolacrimal ducts contains aquaporins (AQPs), a family of membrane proteins that function as selective pores and are able to transport water, glycerol, and other small solutes across the cell plasma membrane.

METHODS

Expression of AQPs 0 and 1-10 in human nasolacrimal duct tissue was determined by reverse transcription polymerase chain reaction (RT-PCR). Positive PCR amplification products were verified by direct cDNA sequencing. Western blot analysis was used to detect AQPs 3-5. Antisera specific for AQPs were used in immunohistochemical analysis to determine the presence and distribution of ten AQPs (AQP 0 and 1-9) in epithelia and subepithelial glands of the nasolacrimal ducts. All samples investigated originated from human postmortem tissue.

RESULTS

In human nasolacrimal duct samples, AQPs 1, 3, 4, 5, 7, 8, 9, and 10 were identified by RT-PCR. No RT-PCR products were detected for AQPs 0, 2, and 6. All AQPs, which were detected by RT-PCR, were also confirmed by direct sequencing of the cDNA. Immunohistochemical analyses revealed AQPs 1, 3, 5, 7, 8, and 9 in human nasolacrimal duct epithelium and were detected in different cells. Expression of AQP 4 could not be detected immunohistochemically but by Western blot analysis. Protein detection of AQP 10 could not be performed due to the unavailability of an appropriate antibody.

CONCLUSIONS

The results suggest specific roles for AQPs in water transport through the epithelium of the nasolacrimal ducts and underline the presumption that tear fluid components are selectively absorbed in the nasolacrimal passage.

Molecular and structural basis of metabolic diversity mediated by prenyldiphosphate converting enzymes

General thermodynamic calculations using the semiempiric PM3 method have led to the conclusion that prenyldiphosphate converting enzymes require at least one divalent metal cation for the activation and cleavage of the diphosphate-prenyl ester bond, or they must provide structural elements for the efficient stabilization of the intermediate prenyl cation. The most important common structural features, which guide the product specificity in both terpene synthases and aromatic prenyl transferases are aromatic amino acid side chains, which stabilize prenyl cations by cation-pi interactions. In the case of aromatic prenyl transferases, a proton abstraction from the phenolic hydroxyl group of the second substrate will enhance the electron density in the phenolic ortho-position at which initial prenylation of the aromatic compound usually occurs. A model of the structure of the integral transmembrane-bound aromatic prenyl transferase UbiA was developed, which currently represents the first structural insight into this group of prenylating enzymes with a fold different from most other aromatic prenyl transferases. Based on this model, the structure-activity relationships and mechanistic aspects of related proteins, for example those of Lithospermum erythrorhizon or the enzyme AuaA from Stigmatella aurantiaca involved in the aurachin biosynthesis, were elucidated. The high similarity of this group of aromatic prenyltransferases to 5-epi-aristolochene synthase is an indication of an evolutionary relationship with terpene synthases (cyclases). This is further supported by the conserved DxxxD motif found in both protein families. In contrast, there is no such relationship to the aromatic prenyl transferases with an ABBA-fold, such as NphB, or to any other known family of prenyl converting enzymes. Therefore, it is possible that these two groups might have different evolutionary ancestors.

Somatostatin actions via somatostatin receptors on the ocular surface are modulated by inflammatory processes

Recent investigations support the presence of human somatostatin (SS) in the excretory system of the human lacrimal gland. To get deeper insights into a possible role of SS at the ocular surface and in the lacrimal apparatus, we investigated the distribution pattern of SS and its receptors 1-5 (SSTR1-5) by means of RT-PCR, real-time RT-PCR, Western blot and immunodot blot analysis as well as immunohistochemistry in lacrimal gland, tear fluid, conjunctiva, cornea, nasolacrimal duct epithelium, and conjunctival (HCjE) and corneal (HCE) epithelial cell lines. Cell culture experiments with HCjE and HCE were performed to analyze a possible impact of SS and inflammatory mediators on the regulation of SSTR. The results confirmed the presence of SS in lacrimal gland and tear fluid, whereas it was absent at the protein level in all other tissues and cell lines investigated. Expression of SSTR1, -2, and -5 was detectable in lacrimal gland, conjunctiva, cornea, and nasolacrimal ducts. HCjE expressed only hSSTR1 and -2, and HCE revealed only SSTR2. SSTR3 and -4 were not detected in any of the analyzed samples or cell lines. In vitro on cultured immortalized HCjE cells SS leads to a concentration-dependent down-regulation of SSTR1 mRNA but does not affect SSTR2 mRNA expression. Relative expression of SSTR1 and -2 is differentially modulated by proinflammatory cytokines and bacterial components, suggesting that the expression of both receptors is immunomodulated. Our data support an autocrine and paracrine role of SS in the lacrimal system and at the ocular surface and implicate a role of SS in corneal immunology.

Postmortal diagnosis of a Dyke-Davidoff-Masson syndrome in a 75-year-old woman---a case report

The Dyke-Davidoff-Masson syndrome is characterized by various symptoms related to hemiatrophy of the cerebrum and hypertrophy of the ipsilateral calvarium and paranasal sinuses. Clinical findings include hemiparesis or hemiplegia, seizures and/or mental retardation. The present report discusses the very unusual case of a late-diagnosed Dyke-Davidoff-Masson syndrome in a 75-year-old body donor who had suffered a left-sided stroke associated with the internal carotid artery in the course of tonsillitis at the age of 5.