A blueprint of the topology and mechanics of the human ovary for next-generation bioengineering and diagnosis.

Although the first dissection of the human ovary dates back to the 17th century, the biophysical characteristics of the ovarian cell microenvironment are still poorly understood. However, this information is vital to deciphering cellular processes such as proliferation, morphology and differentiation, as well as pathologies like tumor progression, as demonstrated in other biological tissues. Here, we provide the first readout of human ovarian fiber morphology, interstitial and perifollicular fiber orientation, pore geometry, topography and surface roughness, and elastic and viscoelastic properties. By determining differences between healthy prepubertal, reproductive-age, and menopausal ovarian tissue, we unravel and elucidate a unique biophysical phenotype of reproductive-age tissue, bridging biophysics and female fertility. While these data enable to design of more biomimetic scaffolds for the tissue-engineered ovary, our analysis pipeline is applicable for the characterization of other organs in physiological or pathological states to reveal their biophysical markers or design their bioinspired analogs.

The role of ultrasound in front-of-neck access for cricothyroid membrane identification: A systematic review.

PURPOSE: Conventional palpation techniques for cricothyroid membrane (CTM) identification are inaccurate and unreliable. Ultrasound plays a multi-faceted role in airway management, however there is limited literature around its use for CTM identification prior to cricothyrotomies. This review sought to compare ultrasound to palpation in the general population, identify its indications in subjects with ill-defined neck anatomy, and determine its role in defining neck anatomy. METHODS: Two reviewers independently assessed titles, abstracts and full-text English articles through the Ovid Medline and EMBASE databases. Studies related to ultrasound for CTM assessment and/or cricothyrotomy in subjects older than 12 years were included. RESULTS: Fourteen studies were selected. Compared to palpation, ultrasound has greater accuracy, but longer CTM identification times in those with normal airway anatomy. Interestingly, ultrasound offers comparable times to palpation in patients with difficult airways. Ultrasound also helps define anatomical parameters in the neutral and extended neck positions thereby underscoring the importance of neck positioning during cricothyrotomies and confirming consensus-based incision recommendations set by the Difficult Airway Society. CONCLUSION: Ultrasound appears to be superior to palpation for CTM localization especially in those with difficult airway anatomy and objectively defines neck anatomy. Its pre-emptive use should be incorporated during difficult airway management.

Estimating the amount of collagen and elastic fibres in bovine teats.

The amount of collagen and elastic fibres near the Fürstenberg's rosette in histological sections of bovine teats was estimated using the ImageJ image processing software. This method holds promise for comparing tissue types within and between sections but it was not a reliable way to quantify the absolute amount of tissue types in a sample. The amount of elastic fibres and collagen was similar in cow teats with a history or acute case of mastitis infection and in non-infected cows, but this could not be statistically tested due to limitations in the study material.

Structural topography of the interosseous membrane of the human forearm.

The aim of this study was to evaluate the morphology of the six different parts of the interosseous membrane (IOM) in 11 human cadaver forearms, including the distal oblique bundle (DOB), the distal accessory band (DAB), the central band (CB), the proximal accessory band (PAB), the dorsal oblique accessory cord (DOAC), and the proximal oblique cord (POC). Hematoxylin-eosin and Elastica van Gieson stained slices were used to investigate the tissue morphology. The DOB and DOAC were absent in one IOM and the POB in two IOMs, respectively. The CB and DAB were longer than all other structures except for each other. The DOAC was longer than the DOB. The DAB, CB, and PAB, were broader than the DOB, DOAC, and POC. No significant differences were observed regarding structure thickness. All structures were found to consist of densely packed parallel collagen fiber arrangement. The DOB and POC had a higher amount of elastic fibers in the fascicular collagen tissue than the other structures. Elastic fibers were more often equally distributed throughout the structures than condensed epifascicular or at the insertion into bone. The tight parallel collagen composition within the different structures reflects the central stabilizing role of the IOM in the forearm. The higher amount of elastic fibers within the DOB and POC can be attributed to their location close to the distal and proximal radioulnar joints, respectively. Here elastic fibers allow adaption to forearm rotation, whereas the structures of the central part of IOM have less elasticity reflecting the predominant stabilizing function.

Bilaminar Structure of the Human Optic Nerve Sheath.

PURPOSE/AIM: We aimed to characterize the connective tissue microanatomy, elastin abundance, and fiber orientation in the human optic nerve sheath, also known as the optic nerve dura mater, for correlation with its biomechanical properties. MATERIALS AND METHODS: Seven whole human orbits aged 4-93 years, and five isolated human optic nerve sheaths aged 26-75 years were formalin fixed, paraffin embedded, coronally sectioned, stained by Masson trichrome and van Gieson's elastin methods, and analyzed quantitatively for elastin fiber abundance and orientation. Elastin area fraction was defined as area stained for elastin divided by total area. RESULTS: While unilaminar in children, the adult ON sheath exhibited distinct inner and outer layers. Collagen was denser and more compact in the inner layer. Elastin area fraction was significantly greater at 6.0 ± 0.4% (standard error of mean) in the inner than outer layer at 3.6 ± 0.4% (P < 10-5). Elastin fibers had three predominant orientations: longitudinal, diagonal, and circumferential. Of circumferential fibers, 63 ± 4.7% were in the inner and 37 ± 4.7% in the outer layer (P < 10-4). Longitudinal and diagonal fibers were uniformly distributed in both layers. Elastin density and sheath thickness increased significantly with age (P < .01). CONCLUSIONS: The adult human optic nerve sheath is bilaminar, with each layer containing elastin fibers oriented in multiple directions consistent with isotropic properties. Differences in laminar elastin density and orientation may reflect greater tensile loading in the inner than in the outer layer.

The vocal organ of hummingbirds shows convergence with songbirds.

How sound is generated in the hummingbird syrinx is largely unknown despite their complex vocal behavior. To fill this gap, syrinx anatomy of four North American hummingbird species were investigated by histological dissection and contrast-enhanced microCT imaging, as well as measurement of vocalizations in a heliox atmosphere. The placement of the hummingbird syrinx is uniquely located in the neck rather than inside the thorax as in other birds, while the internal structure is bipartite with songbird-like anatomical features, including multiple pairs of intrinsic muscles, a robust tympanum and several accessory cartilages. Lateral labia and medial tympaniform membranes consist of an extracellular matrix containing hyaluronic acid, collagen fibers, but few elastic fibers. Their upper vocal tract, including the trachea, is shorter than predicted for their body size. There are between-species differences in syrinx measurements, despite similar overall morphology. In heliox, fundamental frequency is unchanged while upper-harmonic spectral content decrease in amplitude, indicating that syringeal sounds are produced by airflow-induced labia and membrane vibration. Our findings predict that hummingbirds have fine control of labia and membrane position in the syrinx; adaptations that set them apart from closely related swifts, yet shows convergence in their vocal organs with those of oscines.

Expression of stromal elements of prostatic adenocarcinoma in different gleason scores.

PURPOSE: To quantify and compare the expression of stromal elements in prostate adenocarcinoma of different Gleason scores with non-tumor area (control). METHODS: We obtained 132 specimens from samples of prostate peripheral and transition zone. We analyzed the following elements of the extracellular matrix: collagen fibers, elastic system, smooth muscle fibers and blood vessels. The tumor area and non-tumor area (control) of the TMA (tissue microarray) were photographed and analyzed using the ImageJ software. RESULTS: The comparison between the tumor area and the non-tumor area showed significant differences between stromal prostate elements. There was an increase of collagen fibers in the tumor area, mainly in Gleason 7. Elastic system fibers showed similar result, also from the Gleason 7. Blood vessels showed a significant increase occurred in all analyzed groups. The muscle fibers exhibited a different behavior, with a decrease in relation to the tumor area. CONCLUSIONS: There is a significant difference between the extracellular matrix in prostate cancer compared to the non-tumor area (control) especially in Gleason 7. Important modifications of the prostatic stromal elements strongly correlate with different Gleason scores and can contribute to predict the pathological staging of prostate cancer.

Effects of tadalafil to prevent injury on corpus cavernosum after vascular or nervous peri-prostatic bundle injury. Experimental model in rats.

PURPOSE: To evaluate the effects of tadalafil (TD) in preventing histological alterations of the corpus cavernosum caused by isolated lesions of cavernous nerve (ILCN) and artery (ILCA) in rats. METHODS: Fifty male Wistar rats were randomly assigned in five groups: G1: control; G2: bilateral ILCN; G3: bilateral ILCA; G4: ILCN+TD; G5: ILCA+TD. The cavernous bodies were submitted to histomorphometry, immunohistochemistry and biochemical analysis. RESULTS: Nerve density was significantly higher in G2 and G4 compared to control (22.62±2.84 and 19.53±3.47 vs. 15.72±1.82; respectively, p<0.05). Smooth muscle density was significantly lower in G2 and G3 in comparison to G1 (12.87±1.90 and 18.93±1.51 vs. 21.78±1.81, respectively; p<0.05). A significant decrease in the sinusoidal lumen area was observed in G2 compared to controls (5.01±1.62 vs. 9.88±3.66, respectively; p<0.05) and the blood vessel density was increased in G2 and G3 (29.32±4.13 e 20.80±2.47 vs. 10.13±2.71, p<0.05). Collagen density was higher in G3 compared to G1 (93.76±15.81 vs. 64.59±19.25; p<0.05). CONCLUSIONS: Histomorphometric alterations caused by ILCN were more intense than those produced by vascular injury, but the collagen analyses showed more fibrosis in animals with ILCA. TD was effective in preventing the majority of the alterations induced by the periprostatic bundle injury.

Expression of stromal elements of prostatic adenocarcinoma in different gleason scores

Abstract Purpose: To quantify and compare the expression of stromal elements in prostate adenocarcinoma of different Gleason scores with non-tumor area (control). Methods: We obtained 132 specimens from samples of prostate peripheral and transition zone. We analyzed the following elements of the extracellular matrix: collagen fibers, elastic system, smooth muscle fibers and blood vessels. The tumor area and non-tumor area (control) of the TMA (tissue microarray) were photographed and analyzed using the ImageJ software. Results: The comparison between the tumor area and the non-tumor area showed significant differences between stromal prostate elements. There was an increase of collagen fibers in the tumor area, mainly in Gleason 7. Elastic system fibers showed similar result, also from the Gleason 7. Blood vessels showed a significant increase occurred in all analyzed groups. The muscle fibers exhibited a different behavior, with a decrease in relation to the tumor area. Conclusions: There is a significant difference between the extracellular matrix in prostate cancer compared to the non-tumor area (control) especially in Gleason 7. Important modifications of the prostatic stromal elements strongly correlate with different Gleason scores and can contribute to predict the pathological staging of prostate cancer.

Morphohistometric study of the ligamentum flavum in cervical, thoracic and lumbar vertebrae: comparative approach

Anatomic characterization and fine structure of the human ligamentum flavum (LF), especially at different spinal levels, represent an attractive focus for the scientific and surgical application. Descriptive anatomical and structural study of LF at the cervical, thoracic and lumbar levels of the vertebral column in human cadavers is carried out here. The aim of the work is to clarify the anatomical features and fine structural differences in the human LF at different vertebral levels (cervical, thoracic and lumbar). Specimens of vertebral column were obtained from 34 human preserved cadavers. Their average age ranged between 56 and 69 years. Morphometric parameters including height, width and thickness of the ligament flavum at the midlevels of cervical, thoracic and lumbar regions were measured. Sections obtained from different levels were stained with different stains. Morphometric measurements involved the relative elastic area, relative collagen area, elastic area and collagen area% were measured.The results of the height, width and thickness of the LF at different spinal levels showed gradual increase in their mean values respectively. The LF midline gaps were found in the cervical, thoracic and lumbar regions. The morphometrical measurements showed that the average elastic area was highest in the cervical region and lowest in the thoracic region. In the lumbar region, the percentages of both elastic area and the collagen area were nearly the same. The characterization of morphological and histological aspects of the LF at different spinal levels will be of great importance for applications in spinal surgery, biomechanical and physical rehabilitation of vertebral column

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Study of morphological structure in human fetus Wharton's duct opening area.

OBJECTIVES: Not many morphological studies have been reported regarding the human salivary main duct, especially those based on observations of the fetal salivary main duct at various developmental stages. The relationships between fetal structural development and its function, functional disorders and diseases certainly have clinical significance. METHODS: In this study, we conducted a morphological observation of seven 5-9 month old human fetal sublingual caruncula, the common opening between the submandibular (Wharton's) duct and the sublingual (Bartholin's) duct. After seven specimens were removed and paraffin sections were prepared, HE and EVG staining were used for histological study of structural differences in the various developmental stages. Furthermore, anti-α-SMA staining was used to observe the distribution of the smooth muscle inside of the Wharton's duct wall. RESULTS: An abundance of elastic fibers were observed in the duct walls of both five and nine month old specimens with EVG staining. The smooth muscle fibers of five month old fetus were immature and were starting to distribute throughout the duct wall, whereas nine month old fetus' smooth muscle fibers were further developed and composed in layers. CONCLUSION: In this study, we confirmed that the Wharton's duct wall structure of nine month old fetuses was close to its adult structural formation, while the inner structure consisted of an ample distribution of elastic fibers and smooth muscle fibers. Based on the distribution pattern of the smooth muscle, we speculate that the Wharton's duct's opening area does not possess a sphincter-like function in the regulation of salivary flow.

Effects of tadalafil to prevent injury on corpus cavernosum after vascular or nervous peri-prostatic bundle injury. Experimental model in rats

Abstract Purpose: To evaluate the effects of tadalafil (TD) in preventing histological alterations of the corpus cavernosum caused by isolated lesions of cavernous nerve (ILCN) and artery (ILCA) in rats. Methods: Fifty male Wistar rats were randomly assigned in five groups: G1: control; G2: bilateral ILCN; G3: bilateral ILCA; G4: ILCN+TD; G5: ILCA+TD. The cavernous bodies were submitted to histomorphometry, immunohistochemistry and biochemical analysis. Results: Nerve density was significantly higher in G2 and G4 compared to control (22.62±2.84 and 19.53±3.47 vs. 15.72±1.82; respectively, p<0.05). Smooth muscle density was significantly lower in G2 and G3 in comparison to G1 (12.87±1.90 and 18.93±1.51 vs. 21.78±1.81, respectively; p<0.05). A significant decrease in the sinusoidal lumen area was observed in G2 compared to controls (5.01±1.62 vs. 9.88±3.66, respectively; p<0.05) and the blood vessel density was increased in G2 and G3 (29.32±4.13 e 20.80±2.47 vs. 10.13±2.71, p<0.05). Collagen density was higher in G3 compared to G1 (93.76±15.81 vs. 64.59±19.25; p<0.05). Conclusions: Histomorphometric alterations caused by ILCN were more intense than those produced by vascular injury, but the collagen analyses showed more fibrosis in animals with ILCA. TD was effective in preventing the majority of the alterations induced by the periprostatic bundle injury.

Quantitative analysis of the elastic fiber in the tunica media at the carotid bifurcation.

In this study, the results of our previously reported technique of quantitative analysis by using microscopic image analysis of tissue image slices to calculate the proportion of the area of the tunica media occupied by of elastic fibers was compared with Janzen et al.'s technique at the carotid bifurcation. This particularly analyzed the area of transition between the common carotid and the internal carotid, to observe the quantitative changes in elastic fiber content. The data obtained from our quantitative analysis of elastic fibers were clearly at variance with those obtained by counting the number of elastic fibers. The amount of elastic fibers in the tunica media (the elastic fiber ratio) decreased from the proximal carotid artery (the common carotid) to the bifurcation, then peaked in the internal carotid immediately after the bifurcation before declining again.

Morphological analysis of the elastic and collagen fibers in the ram penis / Análise morfológica de fibras elásticas e colágenas no pênis de ovinos

The penis represents the organ of the male's copulation. It is essential to know the reproductive biology and the morphology of the reproductive organs to increase animal production. In order to contribute to this knowledge and provides information on the ram reproductive morphology, the purpose of this work was to describe the distribution, based on light microscopy, of the collagen and elastic fibers in the ram penis. For that, were collected transverse fragments of the penis (root, sigmoid flexure, body and glans) of seven rams. The specimens were fixed in paraformaldehyde for 24h and destined for the histological routine. The extracellular matrix of the ram penis was composed of collagen and elastic fibers. The penis was enveloped by the tunica albuginea, consisting essentially of collagen fibers, which were arranged in two layers: an outer longitudinal and an inner circular. This tunic emitted septa that penetrated the corpus cavernosum. The elastic fibers appeared transversely and longitudinally in the corpus cavernosum, corpus spongiosum, and next to the neurovascular bundle of the penis. This structure was not different to that reported for other domestic ruminants such as cattle and buffaloes.(AU)

O pênis representa o órgão da cópula do macho. É fundamental que se conheça a biologia reprodutiva e a morfologia dos órgãos reprodutores para o incremento da produção animal. Com o objetivo de contribuir para este conhecimento e fornecer informações sobre a morfologia reprodutiva de ovinos, o propósito deste trabalho foi descrever a distribuição, com base na microscopia de luz, das fibras colágenas e elásticas no pênis de ovinos. Para tanto, foram coletados fragmentos transversais do pênis (raiz, flexura sigmoide, corpo e glande) de sete ovinos. Os exemplares foram fixados em paraformaldeído por 24h e destinados à rotina histológica. A matriz extracelular do pênis de ovinos estava constituída por fibras colágenas e elásticas. O pênis estava envolvido pela túnica albugínea, formada essencialmente por fibras colágenas, que estavam arranjadas em duas camadas: longitudinal externa e circular interna. Esta túnica emitiu septos que penetraram no corpo cavernoso. As fibras elásticas apareceram de modo transversal e longitudinal nos corpos cavernoso e esponjoso e junto ao feixe vásculo-nervoso do pênis de ovinos. Esta estrutura mostrou-se similar ao encontrado em outros ruminantes domésticos como bovinos e bubalinos.(AU)

A comparative study of the elastic fibre system within the mouse and human cornea.

The cornea relies on its organised extracellular matrix for maintaining transparency and biomechanical strength. Studies have identified an elastic fibre system within the human posterior cornea, thought to allow for slight deformations in response to internal pressure fluctuations within the eye. However, the type of elastic fibres that exist within the cornea and their roles remain elusive. The aim of this study was to compare the distribution and organisation of the elastic fibres within the posterior peripheral mouse and human cornea, and elucidate how these fibres integrate with the trabecular meshwork, whilst characterising the distribution of their main likely components (fibrillin-1, elastin and type VI collagen) in different parts of the cornea and adjacent sclera. We identified key differences in the elastic fibre system between the human and mouse cornea. True elastic fibres (containing elastin) were identified within the human posterior peripheral cornea. Elastic fibres appeared to present as an extensive network throughout the mouse corneal stroma, but as fibrillin-rich microfibril bundles rather than true elastic fibres. However, tropoelastin staining indicated the possibility that true elastic fibres had yet to develop in the young mice studied. Differences were also apparent within the anatomy of the trabecular meshwork. The human trabecular meshwork appeared to insert between the corneal stroma and Descemet's membrane, with elastic fibres continuing into the stroma from the trabecular meshwork anterior to Descemet's membrane. Within the mouse cornea, no clear insertion point of the trabecular meshwork was seen, instead the elastic fibres within the trabecular meshwork continued into Descemet's membrane, with the trabecular meshwork joining posterior to Descemet's membrane.

Histological characterization of umbilical cord in alpaca (Vicugna pacos).

The histomorphometric features of umbilical cord constituents in seven foetuses of alpaca (Vicugna pacos) from Cerro de Pasco, Department, Peru, were determined. Sections of 2-5 cm of umbilical cord were fixed in 10% neutral buffered formalin and processed for light microscopy. Standard histological slides stained with haematoxylin and eosin, Masson's trichrome and Van Gieson's trichrome were obtained. Histologically, common features of umbilical artery and vein were observed as well as mucous connective tissue, some cell features that compound this tissue constituted by cells presented features of myofibroblasts. Among most important findings that were observed, the lumen of umbilical vein was obliterated into star-shaped form with the thinner umbilical artery wall; the smooth muscles and fibroblast were comparatively more in number in umbilical artery than that of umbilical vein, and the tunica media was larger in dimension than the tunica adventitia in umbilical vein. Conclusively, this histological study features an observation of the umbilical cord of alpaca foetuses and shows the similarity between them and those of other mammal species, including dromedaries and South American camelids.

Organization of the dermal matrix impacts the biomechanical properties of skin.

BACKGROUND: Human skin has the crucial roles of maintaining homeostasis and protecting against the external environment. Skin offers protection against mechanical trauma due to the reversible deformation of its structure; these biomechanical properties are amenable to dynamic testing using noninvasive devices. OBJECTIVES: To characterize the biomechanical properties of young, black African/African-Caribbean and white Northern European skin from different anatomical sites, and to relate underlying skin architecture to biomechanical function. METHODS: Using cutometry and ballistometry, the biomechanical properties of buttock and dorsal forearm skin were determined in black African/African-Caribbean (n = 18) and white Northern European (n = 20) individuals aged 18-30 years. Skin biopsies were obtained from a subset of the volunteers (black African/African-Caribbean, n = 5; white Northern European, n = 6) and processed for histological and immunohistochemical detection of the major elastic fibre components and fibrillar collagens. RESULTS: We have determined that healthy skin from young African and white Northern European individuals has similar biomechanical properties (F3): the skin is resilient (capable of returning to its original position following deformation, R1), exhibits minimal fatigue (R4) and is highly elastic (R2, R5 and R7). At the histological level, skin with these biomechanical properties is imbued with strong interdigitation of the rete ridges at the dermoepidermal junction (DEJ) and candelabra-like arrays of elastic fibres throughout the papillary dermis. Dramatic disruption to this highly organized arrangement of elastic fibres, effacement of the rete ridges and alterations to the alignment of the fibrillar collagens is apparent in the white Northern European forearm and coincides with a marked decline in biomechanical function. CONCLUSIONS: Maintenance of skin architecture - both epidermal morphology and elastic fibre arrangement - is essential for optimal skin biomechanical properties. Disruption to underlying skin architecture, as observed in the young white Northern European forearm, compromises biomechanical function.

How many Layers has the Adventitia? - Structure of the Arterial Tunica Externa Revisited.

Tunica adventitia or tunica externa is the outer layer of the blood vessel wall. It consists of connective tissue with vasa and nervi vasorum and plays a key role in vascular health. The aim of our study was to compare the wall layers beyond tunica media in arteries of different type and location. The following arteries of pig, dog and cat were processed histologically and analysed by light microscopy: aorta ascendens, arcus aortae, aorta thoracica, aorta abdominalis, arteria (a.) femoralis, a. tibialis cranialis, a. carotis communis, a. lingualis, a. basilaris, a. cerebralis media, a. testicularis and aa. jejunales. We found two layers of connective tissue outside the media: (1) a compact layer with many elastic fibres in muscular and few in elastic arteries and (2) an outer layer of loose connective tissue. The compact layer was missing in aorta ascendens, arcus aortae and intracranial vessels. Adventitial stripping removed only the loose connective tissue layer. In spite of the still present compact layer, stripped arteries were very flimsy. We suggest using the term 'tunica externa' for the compact connective tissue layer and 'tunica adventitia' for the outermost loose connective tissue layer as in other organs. The presence of the tunica externa differs between species, arteries and arterial side, as well as the removability of tunica adventitia and tunica externa by anatomical dissection.

Histological investigation of common insensate flaps obtained from the hand and forearm regions for use in fingertip reconstruction.

OBJECTIVE: Many skin flaps have been described for fingertip reconstruction; however, they have not been compared histologically. The aim of this study is to compare the histological features of common insensate flaps that are used for fingertip reconstruction. METHOD: Skin from fingertips and common flap donor sites on the hand and forearm of cadavers were harvested. This study investigated four histological characteristics, namely thickness of the epidermis and dermis; the ratio of collagen to elastic fibres (C/E ratio) in subdermal tissues, and distribution densities of Merkel cells and Meissner's corpuscles. It then compared the values obtained to determine which flap donor site best matched the fingertip. RESULTS: Epidermal thickness of the reverse digital artery island flap, thenar flap, and hypothenar flap was similar to that of fingertip tissue; dermal thickness of the hypothenar flap was similar to that of fingertip tissue. The C/E ratio of the reverse digital artery island flap was similar to that of fingertip tissue. Merkel cells were abundant in the reverse digital artery island flap, but Meissner's corpuscles were few in each of the flaps compared with fingertip tissue. CONCLUSION: The flap donor site with histological properties most similar to fingertip tissue was the palmar lateral aspect at the finger base, representative of the reverse digital artery island flap with respect to epidermal thickness, C/E ratio, and presence of Merkel cells. The thenar and hypothenar flaps also showed similar properties.