Horst Claassen - Academia.edu (original) (raw)
Papers by Horst Claassen
Kompaktwissen Kopf- und Halsanatomie, 2018
Facharztwissen HNO-Heilkunde
Facharztwissen HNO-Heilkunde
Medicina
Background and Objectives: A rare case of cor triatriatum sinistrum in combination with anomalies... more Background and Objectives: A rare case of cor triatriatum sinistrum in combination with anomalies in the atrial septum and in the right atrium of a 60-year-old female body donor is described here. Materials and Methods: In addition to classical dissection, ultrasound and magnetic resonance imaging, computer tomography and cinematic rendering were performed. In a reference series of 59 regularly formed hearts (33 men, 26 women), we looked for features in the left and right atrium or atrial septum. In addition, we measured the atrial and ventricular wall thickness in 15 regularly formed hearts (7 men, 8 women). Results: In the case described, the left atrium was partly divided into two chambers by an intra-atrial membrane penetrated by two small openings. The 2.5 cm-high membrane originated in the upper level of the oval fossa and left an opening of about 4 cm in diameter. Apparently, the membrane did not lead to a functionally significant flow obstruction due to the broad intra-atria...
PloS one, 2018
Surfactant Proteins (SPs) are well known from lung and form, along with phospholipids, a surface-... more 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. Immunohistochemistry, RT-PCR, qRT-PCR, ELISA, Western blotting were performed in cell cultures and tissue samples to determine localization, regulation, and concentration of SPs. 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...
Zeitschrift für Orthopädie und ihre Grenzgebiete
The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society, 2017
Laryngeal cartilages undergo a slow ossification process during aging, making them an excellent m... more Laryngeal cartilages undergo a slow ossification process during aging, making them an excellent model for studying cartilage mineralization and ossification processes. Pig laryngeal cartilages are similar to their human counterparts in shape and size, also undergo mineralization, facilitating the study of cartilage mineralization. We investigated the processes of cartilage mineralization and ossification and compared these with the known processes in growth plates. Thyroid cartilages from glutaraldehyde-perfused male minipigs and from domestic pigs were used for X-ray, light microscopic, and transmission electron microscopic analyses. We applied different fixation and postfixation solutions to preserve cell shape, proteoglycans, and membranes. In contrast to the ossifying human thyroid cartilage, predominantly cartilage mineralization was observed in minipig and domestic pig thyroid cartilages. The same subset of chondrocytes responsible for growth plate mineralization is also prese...
Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft, 2016
Variations in the brachial plexus are the rule rather than the exception. This fact is of special... more Variations in the brachial plexus are the rule rather than the exception. This fact is of special interest for the anesthetist when planning axillary block of brachial plexus. 167 cadaver arms were evaluated for variations in brachial plexus, with focus on the cords of the plexus, the loop of the median nerve, and the course of the median, musculocutaneous, ulnar, axillary and radial nerves. In addition, concomitant arterial variations were recorded. In 167 arms, variations were detected in 60 cases (36%). With 46 arms (28%) most variations concern the median nerve, followed by 13 cases (8%) which involved the musculocutaneous nerve. Ulnar, axillary and radial nerve variations were rare, amounting to 1.2% for each nerve. In median nerve conditions with a shifted loop of median nerve (12%), a hidden position of the loop or a hidden course of the beginning median nerve (8%) and a doubled loop of median nerve (17%) were observed. In musculocutaneous nerve conditions with a non-perforat...
Ann Anatomy, 2003
While dissecting the body of a 75-year-old male we observed variations in the Mm. flexor digitoru... more While dissecting the body of a 75-year-old male we observed variations in the Mm. flexor digitorum brevis and longus of both feet. In the left foot, the 4 th tendon of the M. flexor digitorum brevis was atrophied and the respective tendon of the M. flexor digitorum longus to the little toe was absent. In the right foot, the 4 th tendons of both the Mm. flexor digitorum brevis and longus to the little toe were absent. The lacking deep flexor tendon to the little toe in the left foot was replaced by an isolated flexor muscle originating from the medial and lateral processes of the calcaneal tuberosity, which additionally had connections to the tendinous plate of the M. flexor digitorum longus and the M. quadratus plantae. The absent superficial and deep flexor tendons to the little toe in the right foot were replaced by an isolated flexor muscle arising from the M. quadratus plantae distal from the medial process of the calcaneal tuberosity. The tendon of both isolated flexor muscles inserted in the distal phalanx of the little toe. The left isolated flexor muscle for the little toe had connections to the M. flexor digitorum longus and the M. quadratus plantae. From these results it seems likely that the M. quadratus plantae could be regarded as additional flexor head (caput breve or plantare) of the M. flexor digitorum longus as is described in classic textbooks. In the individual's lifetime the described variation perhaps led to the possibility of an isolated flexion of the little toe.
Surg Radiol Anatomy, 2008
Background A large patent median artery can be involved in several clinical disorders like carpal... more Background A large patent median artery can be involved in several clinical disorders like carpal tunnel syndrome, anterior interosseous nerve syndrome and pronator syndrome. Methods The frequency and variability in the expression of the median artery and the expression of the other forearm arteries were recorded during two dissection courses. The topography of the arteries with their ramiWcations was documented on diagrams and photographs. The outer diameters of forearm arteries were measured. Results A large median artery was found in 4 of 54 arms (7.4%). The median arteries took their origin from the ulnar artery or the common interosseous artery. In one case, the median artery pierced the median nerve in its course under the pronator teres. The outer diameters of the median arteries varied between 1.5 and 2.0 mm proximally and 1.5 and 2.0 mm distally. The diameters of the radial arteries varied between 3.0 and 5.5 mm proximally and 3.0 and 4.0 mm distally and were not reduced in any of the four cases with a large median artery. Conclusions Surgeons should be aware of other variations in the forearm when a persistent median artery is iden-tiWed, for example high median nerve bifurcations. Furthermore, it should be kept in mind that additional structures leading to nerve compression may be present in the carpal tunnel.
Magnetic resonance imaging, 2000
Non-invasive assessment of cartilage properties, specifically water content, could prove helpful ... more Non-invasive assessment of cartilage properties, specifically water content, could prove helpful in the diagnosis of early degenerative joint diseases. Transverse relaxation times T(2) of human articular cartilage (34 cartilage slices of three donors) were measured on a pixel-by-pixel basis in a clinical whole body MR system in vitro. In vivo feasibility to measure quantitative T(2) maps was shown for human patellar cartilage. The relaxation times of cartilage with collagen in the radial zone oriented perpendicular to the magnetic field increased from approximately 10 ms near the bone to approximately 60 ms near the articular surface. Cartilage water content of the tibial plateau and femoral condyles could be determined from the correlation with T(2) (R(2) = 0.71) with an error of approximately 2 wt.%. In vivo, directional variation would need to be considered. If confirmed in vivo, T(2) measurements could potentially serve as a non-invasive tool for the evaluation of the status and...
![Research paper thumbnail of [Functional anatomy of the larynx from clinical viewpoints. Part I: development, laryngeal skeleton, joints, insertion structures, musculature]](https://attachments.academia-assets.com/74872807/thumbnails/1.jpg)
](HNO, 2007
ENT specialist and phoniatricians are not the only professionals for whom diseases of the larynx ... more ENT specialist and phoniatricians are not the only professionals for whom diseases of the larynx occupy centre stage; this applies to those in all fields involving conservative or surgical treatment of the larynx, such as speech therapists, paediatricians, anaesthetists, oncologists, pulmonologists, radiologists and general practitioners. On the basis of current knowledge and taking account of results yielded by their own research in recent years and of clinical aspects, in this paper the authors give a short overview of basic knowledge on the anatomy and physiology of the larynx. Part 1 deals with its development and division, the laryngeal skeleton and joints, the insertion structures of the vocal folds and the laryngeal musculature and describes new insights into the mineralization and ossification of the laryngeal skeleton and their implications for phonation, arytenoid subluxation, degenerative joint changes and the biomechanics of vocal cord insertion.
![Research paper thumbnail of [Functional anatomy of the larynx from clinical points of view: part II: Laryngeal mucous membrane, blood supply, innervation, lymphatic drainage, age-related changes]](https://attachments.academia-assets.com/74872809/thumbnails/1.jpg)
](HNO, 2007
Diseases of the larynx are of concern not only for ear, nose, and throat physicians and phoniatri... more Diseases of the larynx are of concern not only for ear, nose, and throat physicians and phoniatricians but also for other clinicians who treat the larynx either conservatively or surgically, including speech therapists, pediatricians, anesthetists, oncologists, pulmonologists, radiologists, and general practitioners. Based on today's state of knowledge and taking into account our own research results of the last years as well as clinical points of view, the present contribution gives a short overview of the anatomy and physiology of the larynx. Part 2 discusses the functional anatomy of the laryngeal mucous membrane (glycoconjugates, mucins, trefoil factor family peptides, antimicrobial substances, larynx-associated lymphoid tissue), the vascular supply, innervation, and lymphatic drainage, as well as age-related laryngeal changes and their effects on swallowing, breathing, and phonation.
Arthritis Research & Therapy, 2014
Introduction: Sex hormones, especially estrogens, have been implicated in articular cartilage met... more 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.
Surgical and Radiologic Anatomy, 2013
Compression of the ulnar nerve at Guyon&a... more Compression of the ulnar nerve at Guyon's canal can be caused not only by tumor-like structures, a fibrotic arch, a ganglion, lipoma, aneurysm or thrombosis but also by anomalous hypothenar muscles which are reviewed here. For the search of relevant papers, PubMed and crucial anatomical textbooks were consulted. The abductor digiti minimi is the most variable hypothenar muscle. It can possess one to three muscle bellies. Additional heads can arise from the flexor retinaculum, the palmaris longus tendon, the pronator quadratus tendon or the deep fascia of the palmar side of the forearm. Our own case of an aberrant abductor digiti minimi appearing like connective tissue and originating in the antebrachial fascia is included here. Hematoxylin and eosin staining revealed that macroscopically non-muscle-like tissue contained skeletal muscle tissue. The muscle itself resembled other described cases. In addition, at the flexor digiti minimi accessory heads with origin from the flexor retinaculum, the antebrachial fascia or the long flexor muscles of the forearm can be detected. By contrast, the opponens digiti minimi mostly lacks variations and is sometimes missing. In our opinion, this is due to its hidden location. However, in few cases an additional head can arise from the lower arm aponeurosis. Furthermore, additional (fourth) hypothenar muscles might be expressed. These muscles are characterized by origins in the forearm and insertions on the head of the 5th metacarpal bone or on the 5th proximal phalanx. It must be noted that accessory hypothenar muscles might look like connective tissue at first glance. Often their origin extends to the antebrachial fascia. This can be explained by the phylogenetic fact that all intrinsic muscles of the hand are derived from muscle masses that originated in the forearm. In the opinion of several authors, ulnar nerve compression mostly is evoked by hyper trophied variant hypothenar muscles due to overuse as for example in carpenters. In some rare cases, an aberrant hypothenar muscle can also evoke median nerve compression.
Surgical and Radiologic Anatomy, 2008
Background A large patent median artery can be involved in several clinical disorders like carpal... more Background A large patent median artery can be involved in several clinical disorders like carpal tunnel syndrome, anterior interosseous nerve syndrome and pronator syndrome. Methods The frequency and variability in the expression of the median artery and the expression of the other forearm arteries were recorded during two dissection courses. The topography of the arteries with their ramiWcations was documented on diagrams and photographs. The outer diameters of forearm arteries were measured. Results A large median artery was found in 4 of 54 arms (7.4%). The median arteries took their origin from the ulnar artery or the common interosseous artery. In one case, the median artery pierced the median nerve in its course under the pronator teres. The outer diameters of the median arteries varied between 1.5 and 2.0 mm proximally and 1.5 and 2.0 mm distally. The diameters of the radial arteries varied between 3.0 and 5.5 mm proximally and 3.0 and 4.0 mm distally and were not reduced in any of the four cases with a large median artery. Conclusions Surgeons should be aware of other variations in the forearm when a persistent median artery is iden-tiWed, for example high median nerve bifurcations. Furthermore, it should be kept in mind that additional structures leading to nerve compression may be present in the carpal tunnel.
Journal of Anatomy, 2004
The role of glycosaminoglycans (GAG) in the process of cartilage mineralization, especially in th... more The role of glycosaminoglycans (GAG) in the process of cartilage mineralization, especially in the hypertrophic zone of growth plates, is not yet fully understood. Human thyroid cartilage can serve as a model to observe matrix changes associated with cartilage mineralization because the processes follow a distinct route, progress very slowly and show sexual differences. Histochemical staining for low sulphated GAG (chondroitin-4-and-6-sulphates) was decreased in the interterritorial matrix of thyroid cartilage starting at the beginning of the fifth decade, but not in the pericellular or territorial matrix of chondrocytes. Because cartilage mineralization progressed in the interterritorial matrix it seems likely that a decreasing content of chondroitin-4-and-6-sulphates is involved in the mineralization process. This hypothesis is supported by the observation that immunostaining for chondroitin-4and-6-sulphates was weaker in mineralized cartilage areas than in unmineralized areas, whereas there was no difference in staining for keratan sulphate. In all life decades, female thyroid cartilages contained more chondrocytes with a territorial rim of chondroitin-4-and-6-sulphates probably preventing cartilage mineralization compared with age-matched male specimens. Taken together, the characteristic distribution pattern of chondroitin-4-and-6-sulphates being more concentrated in female than in male thyroid cartilages provided evidence that these macromolecules decrease in cartilage mineralization.
Histochemistry, 1994
In this study the distribution of type X collagen in thyroid cartilages of various ages is descri... more In this study the distribution of type X collagen in thyroid cartilages of various ages is described. Fetal and juvenile thyroid cartilage was negative for type X collagen, but showed a strong staining reaction for type II collagen. Type X collagen and calcium deposition were first detected in thyroid cartilage of 18-to 21-year-old adults. Type X collagen was restricted to large chondrocytes near or in mineralized cartilage, confirming the notion that type X collagen precedes mineralization. From these observations it was concluded that chondrocytes in thyroid cartilage undergo differentiation steps that are similar, but much slower, compared to cells in growth plate and sternal cartilage. Some type X collagen-positive areas also showed staining for type I collagen, suggesting that there is a further differentiation of chondrocytes to cells which are characterized by the simultaneous synthesis of type X and I collagen. However, a dedifferentiation process during aging of thyroid cartilage where cells switch from synthesis of type II to type I collagen cannot be excluded.
Kompaktwissen Kopf- und Halsanatomie, 2018
Facharztwissen HNO-Heilkunde
Facharztwissen HNO-Heilkunde
Medicina
Background and Objectives: A rare case of cor triatriatum sinistrum in combination with anomalies... more Background and Objectives: A rare case of cor triatriatum sinistrum in combination with anomalies in the atrial septum and in the right atrium of a 60-year-old female body donor is described here. Materials and Methods: In addition to classical dissection, ultrasound and magnetic resonance imaging, computer tomography and cinematic rendering were performed. In a reference series of 59 regularly formed hearts (33 men, 26 women), we looked for features in the left and right atrium or atrial septum. In addition, we measured the atrial and ventricular wall thickness in 15 regularly formed hearts (7 men, 8 women). Results: In the case described, the left atrium was partly divided into two chambers by an intra-atrial membrane penetrated by two small openings. The 2.5 cm-high membrane originated in the upper level of the oval fossa and left an opening of about 4 cm in diameter. Apparently, the membrane did not lead to a functionally significant flow obstruction due to the broad intra-atria...
PloS one, 2018
Surfactant Proteins (SPs) are well known from lung and form, along with phospholipids, a surface-... more 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. Immunohistochemistry, RT-PCR, qRT-PCR, ELISA, Western blotting were performed in cell cultures and tissue samples to determine localization, regulation, and concentration of SPs. 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...
Zeitschrift für Orthopädie und ihre Grenzgebiete
The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society, 2017
Laryngeal cartilages undergo a slow ossification process during aging, making them an excellent m... more Laryngeal cartilages undergo a slow ossification process during aging, making them an excellent model for studying cartilage mineralization and ossification processes. Pig laryngeal cartilages are similar to their human counterparts in shape and size, also undergo mineralization, facilitating the study of cartilage mineralization. We investigated the processes of cartilage mineralization and ossification and compared these with the known processes in growth plates. Thyroid cartilages from glutaraldehyde-perfused male minipigs and from domestic pigs were used for X-ray, light microscopic, and transmission electron microscopic analyses. We applied different fixation and postfixation solutions to preserve cell shape, proteoglycans, and membranes. In contrast to the ossifying human thyroid cartilage, predominantly cartilage mineralization was observed in minipig and domestic pig thyroid cartilages. The same subset of chondrocytes responsible for growth plate mineralization is also prese...
Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft, 2016
Variations in the brachial plexus are the rule rather than the exception. This fact is of special... more Variations in the brachial plexus are the rule rather than the exception. This fact is of special interest for the anesthetist when planning axillary block of brachial plexus. 167 cadaver arms were evaluated for variations in brachial plexus, with focus on the cords of the plexus, the loop of the median nerve, and the course of the median, musculocutaneous, ulnar, axillary and radial nerves. In addition, concomitant arterial variations were recorded. In 167 arms, variations were detected in 60 cases (36%). With 46 arms (28%) most variations concern the median nerve, followed by 13 cases (8%) which involved the musculocutaneous nerve. Ulnar, axillary and radial nerve variations were rare, amounting to 1.2% for each nerve. In median nerve conditions with a shifted loop of median nerve (12%), a hidden position of the loop or a hidden course of the beginning median nerve (8%) and a doubled loop of median nerve (17%) were observed. In musculocutaneous nerve conditions with a non-perforat...
Ann Anatomy, 2003
While dissecting the body of a 75-year-old male we observed variations in the Mm. flexor digitoru... more While dissecting the body of a 75-year-old male we observed variations in the Mm. flexor digitorum brevis and longus of both feet. In the left foot, the 4 th tendon of the M. flexor digitorum brevis was atrophied and the respective tendon of the M. flexor digitorum longus to the little toe was absent. In the right foot, the 4 th tendons of both the Mm. flexor digitorum brevis and longus to the little toe were absent. The lacking deep flexor tendon to the little toe in the left foot was replaced by an isolated flexor muscle originating from the medial and lateral processes of the calcaneal tuberosity, which additionally had connections to the tendinous plate of the M. flexor digitorum longus and the M. quadratus plantae. The absent superficial and deep flexor tendons to the little toe in the right foot were replaced by an isolated flexor muscle arising from the M. quadratus plantae distal from the medial process of the calcaneal tuberosity. The tendon of both isolated flexor muscles inserted in the distal phalanx of the little toe. The left isolated flexor muscle for the little toe had connections to the M. flexor digitorum longus and the M. quadratus plantae. From these results it seems likely that the M. quadratus plantae could be regarded as additional flexor head (caput breve or plantare) of the M. flexor digitorum longus as is described in classic textbooks. In the individual's lifetime the described variation perhaps led to the possibility of an isolated flexion of the little toe.
Surg Radiol Anatomy, 2008
Background A large patent median artery can be involved in several clinical disorders like carpal... more Background A large patent median artery can be involved in several clinical disorders like carpal tunnel syndrome, anterior interosseous nerve syndrome and pronator syndrome. Methods The frequency and variability in the expression of the median artery and the expression of the other forearm arteries were recorded during two dissection courses. The topography of the arteries with their ramiWcations was documented on diagrams and photographs. The outer diameters of forearm arteries were measured. Results A large median artery was found in 4 of 54 arms (7.4%). The median arteries took their origin from the ulnar artery or the common interosseous artery. In one case, the median artery pierced the median nerve in its course under the pronator teres. The outer diameters of the median arteries varied between 1.5 and 2.0 mm proximally and 1.5 and 2.0 mm distally. The diameters of the radial arteries varied between 3.0 and 5.5 mm proximally and 3.0 and 4.0 mm distally and were not reduced in any of the four cases with a large median artery. Conclusions Surgeons should be aware of other variations in the forearm when a persistent median artery is iden-tiWed, for example high median nerve bifurcations. Furthermore, it should be kept in mind that additional structures leading to nerve compression may be present in the carpal tunnel.
Magnetic resonance imaging, 2000
Non-invasive assessment of cartilage properties, specifically water content, could prove helpful ... more Non-invasive assessment of cartilage properties, specifically water content, could prove helpful in the diagnosis of early degenerative joint diseases. Transverse relaxation times T(2) of human articular cartilage (34 cartilage slices of three donors) were measured on a pixel-by-pixel basis in a clinical whole body MR system in vitro. In vivo feasibility to measure quantitative T(2) maps was shown for human patellar cartilage. The relaxation times of cartilage with collagen in the radial zone oriented perpendicular to the magnetic field increased from approximately 10 ms near the bone to approximately 60 ms near the articular surface. Cartilage water content of the tibial plateau and femoral condyles could be determined from the correlation with T(2) (R(2) = 0.71) with an error of approximately 2 wt.%. In vivo, directional variation would need to be considered. If confirmed in vivo, T(2) measurements could potentially serve as a non-invasive tool for the evaluation of the status and...
HNO, 2007
ENT specialist and phoniatricians are not the only professionals for whom diseases of the larynx ... more ENT specialist and phoniatricians are not the only professionals for whom diseases of the larynx occupy centre stage; this applies to those in all fields involving conservative or surgical treatment of the larynx, such as speech therapists, paediatricians, anaesthetists, oncologists, pulmonologists, radiologists and general practitioners. On the basis of current knowledge and taking account of results yielded by their own research in recent years and of clinical aspects, in this paper the authors give a short overview of basic knowledge on the anatomy and physiology of the larynx. Part 1 deals with its development and division, the laryngeal skeleton and joints, the insertion structures of the vocal folds and the laryngeal musculature and describes new insights into the mineralization and ossification of the laryngeal skeleton and their implications for phonation, arytenoid subluxation, degenerative joint changes and the biomechanics of vocal cord insertion.
HNO, 2007
Diseases of the larynx are of concern not only for ear, nose, and throat physicians and phoniatri... more Diseases of the larynx are of concern not only for ear, nose, and throat physicians and phoniatricians but also for other clinicians who treat the larynx either conservatively or surgically, including speech therapists, pediatricians, anesthetists, oncologists, pulmonologists, radiologists, and general practitioners. Based on today's state of knowledge and taking into account our own research results of the last years as well as clinical points of view, the present contribution gives a short overview of the anatomy and physiology of the larynx. Part 2 discusses the functional anatomy of the laryngeal mucous membrane (glycoconjugates, mucins, trefoil factor family peptides, antimicrobial substances, larynx-associated lymphoid tissue), the vascular supply, innervation, and lymphatic drainage, as well as age-related laryngeal changes and their effects on swallowing, breathing, and phonation.
Arthritis Research & Therapy, 2014
Introduction: Sex hormones, especially estrogens, have been implicated in articular cartilage met... more 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.
Surgical and Radiologic Anatomy, 2013
Compression of the ulnar nerve at Guyon&a... more Compression of the ulnar nerve at Guyon's canal can be caused not only by tumor-like structures, a fibrotic arch, a ganglion, lipoma, aneurysm or thrombosis but also by anomalous hypothenar muscles which are reviewed here. For the search of relevant papers, PubMed and crucial anatomical textbooks were consulted. The abductor digiti minimi is the most variable hypothenar muscle. It can possess one to three muscle bellies. Additional heads can arise from the flexor retinaculum, the palmaris longus tendon, the pronator quadratus tendon or the deep fascia of the palmar side of the forearm. Our own case of an aberrant abductor digiti minimi appearing like connective tissue and originating in the antebrachial fascia is included here. Hematoxylin and eosin staining revealed that macroscopically non-muscle-like tissue contained skeletal muscle tissue. The muscle itself resembled other described cases. In addition, at the flexor digiti minimi accessory heads with origin from the flexor retinaculum, the antebrachial fascia or the long flexor muscles of the forearm can be detected. By contrast, the opponens digiti minimi mostly lacks variations and is sometimes missing. In our opinion, this is due to its hidden location. However, in few cases an additional head can arise from the lower arm aponeurosis. Furthermore, additional (fourth) hypothenar muscles might be expressed. These muscles are characterized by origins in the forearm and insertions on the head of the 5th metacarpal bone or on the 5th proximal phalanx. It must be noted that accessory hypothenar muscles might look like connective tissue at first glance. Often their origin extends to the antebrachial fascia. This can be explained by the phylogenetic fact that all intrinsic muscles of the hand are derived from muscle masses that originated in the forearm. In the opinion of several authors, ulnar nerve compression mostly is evoked by hyper trophied variant hypothenar muscles due to overuse as for example in carpenters. In some rare cases, an aberrant hypothenar muscle can also evoke median nerve compression.
Surgical and Radiologic Anatomy, 2008
Background A large patent median artery can be involved in several clinical disorders like carpal... more Background A large patent median artery can be involved in several clinical disorders like carpal tunnel syndrome, anterior interosseous nerve syndrome and pronator syndrome. Methods The frequency and variability in the expression of the median artery and the expression of the other forearm arteries were recorded during two dissection courses. The topography of the arteries with their ramiWcations was documented on diagrams and photographs. The outer diameters of forearm arteries were measured. Results A large median artery was found in 4 of 54 arms (7.4%). The median arteries took their origin from the ulnar artery or the common interosseous artery. In one case, the median artery pierced the median nerve in its course under the pronator teres. The outer diameters of the median arteries varied between 1.5 and 2.0 mm proximally and 1.5 and 2.0 mm distally. The diameters of the radial arteries varied between 3.0 and 5.5 mm proximally and 3.0 and 4.0 mm distally and were not reduced in any of the four cases with a large median artery. Conclusions Surgeons should be aware of other variations in the forearm when a persistent median artery is iden-tiWed, for example high median nerve bifurcations. Furthermore, it should be kept in mind that additional structures leading to nerve compression may be present in the carpal tunnel.
Journal of Anatomy, 2004
The role of glycosaminoglycans (GAG) in the process of cartilage mineralization, especially in th... more The role of glycosaminoglycans (GAG) in the process of cartilage mineralization, especially in the hypertrophic zone of growth plates, is not yet fully understood. Human thyroid cartilage can serve as a model to observe matrix changes associated with cartilage mineralization because the processes follow a distinct route, progress very slowly and show sexual differences. Histochemical staining for low sulphated GAG (chondroitin-4-and-6-sulphates) was decreased in the interterritorial matrix of thyroid cartilage starting at the beginning of the fifth decade, but not in the pericellular or territorial matrix of chondrocytes. Because cartilage mineralization progressed in the interterritorial matrix it seems likely that a decreasing content of chondroitin-4-and-6-sulphates is involved in the mineralization process. This hypothesis is supported by the observation that immunostaining for chondroitin-4and-6-sulphates was weaker in mineralized cartilage areas than in unmineralized areas, whereas there was no difference in staining for keratan sulphate. In all life decades, female thyroid cartilages contained more chondrocytes with a territorial rim of chondroitin-4-and-6-sulphates probably preventing cartilage mineralization compared with age-matched male specimens. Taken together, the characteristic distribution pattern of chondroitin-4-and-6-sulphates being more concentrated in female than in male thyroid cartilages provided evidence that these macromolecules decrease in cartilage mineralization.
Histochemistry, 1994
In this study the distribution of type X collagen in thyroid cartilages of various ages is descri... more In this study the distribution of type X collagen in thyroid cartilages of various ages is described. Fetal and juvenile thyroid cartilage was negative for type X collagen, but showed a strong staining reaction for type II collagen. Type X collagen and calcium deposition were first detected in thyroid cartilage of 18-to 21-year-old adults. Type X collagen was restricted to large chondrocytes near or in mineralized cartilage, confirming the notion that type X collagen precedes mineralization. From these observations it was concluded that chondrocytes in thyroid cartilage undergo differentiation steps that are similar, but much slower, compared to cells in growth plate and sternal cartilage. Some type X collagen-positive areas also showed staining for type I collagen, suggesting that there is a further differentiation of chondrocytes to cells which are characterized by the simultaneous synthesis of type X and I collagen. However, a dedifferentiation process during aging of thyroid cartilage where cells switch from synthesis of type II to type I collagen cannot be excluded.