Local anisotropy in mineralized fibrocartilage and subchondral bone beneath the tendon-bone interface

The enthesis allows the insertion of tendon into bone thanks to several remarkable strategies. This complex and clinically relevant location often features a thin layer of fibrocartilage sandwiched between tendon and bone to cope with a highly heterogeneous mechanical environment. The main purpose of this study was to investigate whether mineralized fibrocartilage and bone close to the enthesis show distinctive three-dimensional microstructural features, possibly to enable load transfer from tendon to bone. As a model, the Achilles tendon-calcaneus bone system of adult rats was investigated with histology, backscattered electron imaging and micro-computed tomography. The microstructural porosity of bone and mineralized fibrocartilage in different locations including enthesis fibrocartilage, periosteal fibrocartilage and bone away from the enthesis was characterized. We showed that calcaneus bone presents a dedicated protrusion of low porosity where the tendon inserts. A spatially resolved analysis of the trabecular network suggests that such protrusion may promote force flow from the tendon to the plantar ligament, while partially relieving the trabecular bone from such a task. Focusing on the tuberosity, highly specific microstructural aspects were highlighted. Firstly, the interface between mineralized and unmineralized fibrocartilage showed the highest roughness at the tuberosity, possibly to increase failure resistance of a region carrying large stresses. Secondly, fibrochondrocyte lacunae inside mineralized fibrocartilage, in analogy with osteocyte lacunae in bone, had a predominant alignment at the enthesis and a rather random organization away from it. Finally, the network of subchondral channels inside the tuberosity was highly anisotropic when compared to contiguous regions. This dual anisotropy of subchondral channels and cell lacunae at the insertion may reflect the alignment of the underlying collagen network. Our findings suggest that the microstructure of fibrocartilage may be linked with the loading environment. Future studies should characterize those microstructural aspects in aged and or diseased conditions to elucidate the poorly understood role of bone and fibrocartilage in enthesis-related pathologies.

Causes of Iris Depigmentation in Young and Middle Age. Clinical Example

The spontaneous change of eyes’ color is a quite rare complain in ophthalmological clinical practice for young and middle-aged patients. We consulted the 18-year-old patient complained that a month ago she noticed a change of the iris’ color. It was symmetrical in both eyes, which had lightened and acquired a “spotty appearance”. Before the appearance of these complaints, the patient had eyes of a rich dark brown color. After a comprehensive examination, the bilateral acute iris depigmentation (BADI) was diagnosed. BADI is bilateral symmetrical iris depigmentation followed by focal or diffuse stromal atrophy and pigment dispersion in the anterior segment. It is more common for young and middle-aged women, and is often asymptomatic. BADI has bilateral symmetrical iris depigmentation followed by focal or diffuse stromal atrophy and pigment dispersion in the anterior eye segment of the eye, which may affect the trabecular network. A feature of this disease is the absence of transillumination, changes in the shape of the pupil, and an inflammatory reaction. In some cases, repigmentation may occur spontaneously during the next few years. Therefore, from a prognostic point this disease has a favorable prognosis. However, patients with BADI syndrome should undergo regular ophthalmological examinations, including measurement of intraocular pressure to exclude the development of secondary open-angle pigmented glaucoma, and use sunglasses when the sun is bright. BADI syndrome must be differentiated with the following diseases: Fuchs heterochromic iridocyclitis, viral iridocyclitis caused by HSV and CMV, pigment dispersion syndrome and pseudo exfoliative glaucoma, as well as bilateral acute iris transillumination (BAIT) syndrome to make a correct diagnosis and apply adequate treatment tactics.

Changing trabecular patterns in panoramic radiographs of Swedish women during 25 years of follow-up

Objectives: The radiographic trabecular pattern on dental radiographs may be used to predict fractures. The aim of this study was to analyze longitudinal changes in the mandibles of 145 females between 1980 and 2005. Methods: Panoramic radiographs were obtained in 1980 and 2005. On 290 radiographs, regions of interest (ROIs) were selected in the ramus, angle and body. In all ROIs, the orientation was measured in 36 directions with the line frequency deviation method. The effects of ageing were analyzed for the fracture and the non-fracture groups separately. Results: During the follow-up, 61 females suffered fractures of the hip, wrist, spine, leg or arm. The fracture and non-fracture groups displayed dissimilar age changes in each investigated ROI. All significant changes pertained to increasing values of line frequency deviation. With increasing age, the trabecular network in the mandible lost details and the trabeculae became more aligned in their main direction. In the “ramus”, the alignment was to the 110–120˚ axis, parallel to the posterior and anterior ramus border. In the “angle”, the alignment was to the 135–150˚ axis, parallel to the oblique line, and in the “body” ROI to the 150–175˚ direction, approximately parallel to the occlusal plane and inferior cortex. Conclusion: Most changes were consistent with the notion that the bone aged less severely in the non-fracture group. In the fracture group, the findings indicate that bone loss leads to redistribution of the remaining bone tissue in such a way that the trabeculae are accentuated perpendicular to the principal loading.

Elastography of the bone-implant interface

The stress distribution around endosseous implants is an important determinant of the surgical success. However, no method developed so far to determine the implant stability is sensitive to the loading conditions of the bone-implant interface (BII). The objective of this study is to investigate whether a quantitative ultrasound (QUS) technique may be used to retrieve information on compressive stresses applied to the BII. An acousto-mechanical device was conceived to compress 18 trabecular bovine bone samples onto coin-shaped implants and to measure the ultrasonic response of the BII during compression. The biomechanical behavior of the trabecular bone samples was modeled as Neo-Hookean. The reflection coefficient of the BII was shown to decrease as a function of the stress during the elastic compression of the trabecular bone samples and during the collapse of the trabecular network, with an average slope of −4.82 GPa−1. The results may be explained by an increase of the bone-implant contact ratio and by changes of bone structure occurring during compression. The sensitivity of the QUS response of the BII to compressive stresses opens new paths in the elaboration of patient specific decision support systems allowing surgeons to assess implant stability that should be developed in the future.

Autonomic Regulation of Penile Erection

Penile erection is a part of the human male sexual response, involving desire, excitation (erection), orgasm (ejaculation), and resolution, and autonomic nerves are involved in all phases. Autonomic innervation of smooth-muscle cells of the erectile tissue is provided by the cavernous nerve. Motor and sensory innervation is derived from the pudendal nerves and their terminal branches, that is, the dorsal nerves of the penis, which carry impulses from receptors harbored in the penile skin, prepuce, and glans. Erection begins with an increased flow in the pudendal arteries and dilatation of the cavernous arteries and helicine arterioles in association with relaxation of the smooth muscles of the trabecular network, causing engorgement of blood in the corpora. This leads to compression of subtunical venules by the resistant tunica albuginea and erection. During detumescence these events are reversed.

The aqueous and methanol extracts of Bambusa vulgaris (Poaceae) improve calcium and phosphorus levels, and bone microstructure in ovariectomized model of osteoporosis

Background Osteoporosis represents the most common metabolic bone disease. Bambusa vulgaris (Poaceae) is a plant with potential antiosteoporotic effects, due to its phytoestrogenic, antioxidative, and anti-inflammatory properties. This study was undertaken to evaluate the effects of aqueous and methanol extracts of B. vulgaris on osteoporosis in rats. Methods Adult female Wistar rats were randomly divided into normal (n = 6) and ovariectomized (n = 42) groups. Twelve weeks after ovariectomy, animals were treated for 4 weeks as follows: distilled water (10 mL/kg, per os (p.o.)), 17β-estradiol (10 μg/kg, intraperitoneal (i.p.)), soya oil (1 mL/kg, i.p.), aqueous or methanol extract of B. vulgaris (55 or 110 mg/kg, p.o.). All rats were weighed daily and sacrificed on day 29. Plasma was collected, and the uterus and femur were dissected out, weighed, and used for biochemical and histological measurements. Results In the untreated ovariectomized females, a non-significant (p > 0.05) increase in body weight and a significant decrease (p < 0.001) in the uterine and bone weights were recorded. Ovariectomy also significantly (p < 0.001) lowered the bone calcium and phosphorus concentrations, and deteriorated the microarchitecture of the femur. Interestingly, B. vulgaris extracts significantly (p < 0.001) improved the bone calcium concentration and femur microarchitecture (increase in trabecular bone density, reorganization of the trabecular network, and increase in bone marrow) with estrogenic-like effects compared to 17β-estradiol. Conclusion These results suggest that B. vulgaris is a potential therapeutic drug for the treatment of osteoporosis. The present findings further justify the ethno-medicinal claims of B. vulgaris.