The embryogenesis of the equine femorotibial joint: The equine interzone

REASONS FOR PERFORMING STUDY

Articular cartilage regeneration is the focus and goal of considerable research effort. Since articular chondrocytes descend from a distinct cohort of progenitor cells located in embryonic nascent joints (interzones), establishing the timing of equine interzone formation is an essential first step towards understanding equine joint and articular cartilage development.

OBJECTIVES

To establish the time frame during which the equine femorotibial interzone forms.

STUDY DESIGN

Descriptive anatomical study.

METHODS

Equine embryos were harvested at 37 (E37), 40, 42, 45, 50 and 65 days' gestation. The femorotibial interzone was examined using high-resolution episcopic microscopy of E37, E42, E45, E50 and E65. Additional histology and collagen-II-immunohistochemistry were performed on E42.

RESULTS

At E37, the femorotibial interzone is first visible as a uniform layer, while at E42 the interzone is fully formed and consists of 3 morphologically distinct layers. The first evidence of cavitation was seen at E45. At E50, the cruciate ligaments were well formed and by E65, joint formation appeared complete.

CONCLUSIONS

The embryogenesis of the equine femorotibial joint is similar to the developmental timeline of stage-matched human and murine embryos. Further studies looking at interzone formation on a cellular and molecular level may further our understanding of the intricate developmental patterns and pathways of articular cartilage development.

GENERATION OF RABBIT PLURIPOTENT STEM CELL LINES

Pluripotent stem cells have the capacity to divide indefinitely and to differentiate to all the somatic tissues. They can be genetically manipulated in vitro by knocking in and out genes, therefore they serve as an excellent tool for gene-function studies and for the generation of models for human diseases. Since 1981, when the first mouse embryonic stem cell (ESC) line was generated, several attempts have been made to generate pluripotent stem cells from other species as it would help us to understand the differences and similarities of signaling pathways involved in pluripotency and differentiation, and would reveal whether the fundamental mechanism controlling self-renewal of pluripotent cells is conserved among different species. This review gives an overlook of embryonic and induced pluripotent stem cell (iPSCs) research in the rabbit which is one of the most relevant non-rodent species for animal models. To date, several lines of putative ESCs and iPSCs have been described in the rabbit. All expressed stem cell-associated markers and exhibited longevity and pluripotency in vitro, but none have been proven to exhibit full pluripotency in vivo. Moreover, similarly to several domestic species, markers used to characterize the putative ESCs are not fully adequate because studies in domestic species have revealed that they are not specific to the pluripotent inner cell mass. Future validation of rabbit pluripotent stem cells would benefit greatly from a reliable panel of molecular markers specific to pluripotent cells of the developing rabbit embryo. The status of isolation and characterization of the putative pluripotency genes in rabbit will be discussed. Using rabbit specific pluripotency genes we might be able to reprogram somatic cells and generate induced pluripotent stem cells more efficiently thus overcome some of the challenges towards harnessing the potential of this technology. This study was financed by EU FP7 (PartnErS, PIAP-GA-2008-218205; InduHeart, PEOPLE-IRG-2008-234390; InduVir, PEOPLE-IRG-2009-245808; RabPstem, PERG07-GA-2010-268422; PluriSys, HEALTH-2007-B-223485; AniStem, PIAP-GA-2011-286264), NKTH-OTKA-EU-7KP HUMAN-MB08-C-80-205; Plurabbit, OMFB-00130-00131/2010 ANR-NKTH/09-GENM-010-01.

Improved cryopreservability of stallion sperm using a sorbitol-based freezing extender

Cryopreservation of stallion semen is often associated with poor post-thaw sperm quality. Sugars are among the important components of a freezing extender and act as non-permeating cryoprotectants. This study aimed to compare the quality of stallion sperm frozen with glucose, fructose or sorbitol-containing freezing extenders. Semen was collected from six stallions of proven fertility and cryopreserved using a freezing extender containing different types of monosaccharide sugars (glucose, fructose or sorbitol). After thawing, the semen was examined for sperm motility, viability, acrosome integrity, plasma membrane functionality and sperm longevity. The fertility of semen frozen in the presence of sorbitol was also tested by artificial insemination. Sperm quality was significantly decreased following freezing and thawing (P < 0.05). Fructose was inferior for protecting sperm during cryopreservation when compared to sorbitol and glucose (P < 0.05). Although the viability, motility and acrosome integrity of sperm cryopreserved with a glucose-containing extender did not significantly differ from sperm frozen in the sorbitol-based extender when examined at 2 and 4 h post-thaw, all of these parameters plus plasma membrane functionality were improved for sperm frozen in the sorbitol extender than in the glucose extender when examined 10 min post-thaw. Two of four mares (50%) inseminated with semen frozen with a sorbitol-containing freezing extender became pregnant. It is concluded that different sugars have different abilities to protect against cryoinjury during freezing and thawing of stallion sperm. This study demonstrated that an extender containing sorbitol as primary sugar can be used to successfully cryopreserve equine sperm; moreover, the quality of frozen-thawed sperm appeared to be better than when glucose or fructose was the principle sugar in the freezing extender.

Etanercept therapy in children with treatment-resistant uveitis

OBJECTIVE

To evaluate the safety and efficacy of the tumor necrosis factor fusion protein etanercept in children with treatment-resistant uveitis.

METHODS

Ten children with chronic active uveitis (7 girls and 3 boys, mean age 7.5 years [range 3-12 years]) were enrolled in this prospective study. In 7 children, uveitis was associated with pauciarticular juvenile rheumatoid arthritis. Five children were antinuclear antibody positive. All patients had failed previous therapy with topical steroids and methotrexate and/or cyclosporine. All were treated with etanercept at a dosage of 0.4 mg/kg twice weekly for the first 3 months, and then, if eyes did not improve, with 25 mg twice weekly (mean 1.1 mg/kg) for at least 3 additional months.

RESULTS

At the beginning of the trial, uveitis affected 18 eyes in the 10 children. Within 3 months, 10 of 16 affected eyes (63%; P = 0.017) showed a rapid decrease in anterior chamber cell density, including remission of uveitis in 4 eyes. In children with visual acuity of less than 20/25, 4 of 10 eyes (40%) improved. An exacerbation of uveitis during etanercept therapy occurred in only 1 child (1 of 14 eyes [7%]). Other ocular outcome parameters, such as intraocular pressure, synechia formation, and lens clarity, remained unchanged. Following a dosage increase to an average of 1.1 mg/kg after 3 months in 7 children, no further improvement was noted.

CONCLUSION

Our data suggest that etanercept injected subcutaneously twice a week has a beneficial effect on treatment-resistant chronic uveitis in children. Further controlled studies with etanercept in systemic or topical form are necessary to confirm its efficacy and optimal mode of administration.

The influence of cognition and age on accommodation, detection rate and response times when using a car head-up display (HUD)

Car head-up displays (HUDs), which portray information in the form of a virtual image reflected off a combiner, allow the viewing of complex information, such as route guidance, without the need for the driver to look away from the road ahead. The cognitive demand required by the HUD task may distract drivers from the outside world scene and cause reaction times to slow. Cognitive capacity also decreases with age. The aim of the present study was to determine the effect of cognitive demand and age on the use of a car HUD. Subjects (young, middle or older age drivers, each group n = 8) performed a HUD-assisted driving task, with three levels of cognitive demand, whilst accommodation was simultaneously measured using a dynamically recording infra-red optometer. Response times to, and the detection rate of, changes in both the HUD image and the outside world scene were analysed. Increasing the cognitive demand associated with the HUD image increased over-accommodation (greatest in the young, 0.34 +/- 0.05 D, p < 0.001). Response times to and detection of changes in the HUD image and outside world scene were significantly worse with increased cognitive demand. Response times to and detection of changes in the HUD image and outside world scene also increased with age. The implication of the results with respect to car HUD design and safety are discussed.

A system for classifying mechanical injuries of the eye (globe). The Ocular Trauma Classification Group

PURPOSE

To develop a classification system for mechanical injuries of the eye.

METHODS

The Ocular Trauma Classification Group, a committee of 13 ophthalmologists from seven separate institutions, was organized to discuss the standardization of ocular trauma classification. To develop the classification system, the group reviewed trauma classification systems in ophthalmology and general medicine and, in detail, reports on the characteristics and outcomes of eye trauma, then established a classification system based on standard terminology and features of eye injuries at initial examination that have demonstrated prognostic significance.

RESULTS

This system classifies both open-globe and closed-globe injuries according to four separate variables: type of injury, based on the mechanism of injury; grade of injury, defined by visual acuity in the injured eye at initial examination; pupil, defined as the presence or absence of a relative afferent pupillary defect in the injured eye; and zone of injury, based on the anteroposterior extent of the injury. This system is designed to be used by ophthalmologists and nonophthalmologists who care for patients or conduct research on ocular injuries. An ocular injury is classified during the initial examination or at the time of the primary surgical intervention and does not require extraordinary testing.

CONCLUSIONS

This classification system will categorize ocular injuries at the time of initial examination. It is designed to promote the use of standard terminology and assessment, with applications to clinical management and research stud ies regarding eye injuries.

A pupil-sparing oculomotor palsy from a contralateral giant intracavernous carotid aneurysm

A patient presenting with a left pupil-sparing oculomotor palsy and periorbital pain was subsequently found to have a giant saccular aneurysm of the right internal carotid artery within the cavernous sinus. The aneurysm was of the contralateral artery compared to the side of all presenting neuro-ophthalmic signs and symptoms. Diagnosis was achieved by bilateral carotid arteriography and surgical treatment with a Crutchfield arterial clamp and bypass graft has returned the patient essentially to normalcy.