3D microfluidic liver cultures as a physiological preclinical tool for hepatitis B virus infection.

With more than 240 million people infected, hepatitis B virus (HBV) is a major health concern. The inability to mimic the complexity of the liver using cell lines and regular primary human hepatocyte (PHH) cultures pose significant limitations for studying host/pathogen interactions. Here, we describe a 3D microfluidic PHH system permissive to HBV infection, which can be maintained for at least 40 days. This system enables the recapitulation of all steps of the HBV life cycle, including the replication of patient-derived HBV and the maintenance of HBV cccDNA. We show that innate immune and cytokine responses following infection with HBV mimic those observed in HBV-infected patients, thus allowing the dissection of pathways important for immune evasion and validation of biomarkers. Additionally, we demonstrate that the co-culture of PHH with other non-parenchymal cells enables the identification of the cellular origin of immune effectors, thus providing a valuable preclinical platform for HBV research.

Necrotising Scleritis and Peripheral Ulcerative Keratitis Associated with Rheumatoid Arthritis Treated with Rituximab.

Background Rheumatoid arthritis is a chronic and common inflammatory autoimmune disease. This primarily involves the synovia of the joints, but can cause many extra-articular manifestations as well, including peripheral ulcerative keratitis (PUK) and necrotising scleritis. These are often a threat to vision; they significantly compromise not only the eye's structural integrity but are also important for prognosis and need urgent management. History and signs Three cases of peripheral ulcerative keratitis associated with rheumatoid arthritis were recorded in the electronic databank of the Jules Gonin Uveitis Clinic, two with necrotising scleritis and peripheral ulcerative keratitis and one with only peripheral ulcerative keratitis. They were all followed at Jules Gonin Eye Hospital (Lausanne, Switzerland), conjointly with the Department of Rheumatology at the Centre Hospitalier Universitaire Vaudois (Lausanne, Switzerland). Therapy and Outcome Good initial therapeutic response was observed in the two patients who received rituximab therapy. The patient who received only high dose corticosteroid developed massive colon perforation as well as acute renal insufficiency a few days after her ocular event. Conclusion From our limited number of patients, we found that the two patients who received the induction therapy with rituximab were stabilised from an ocular standpoint; however, rituximab had to be switched to other molecules, either due to other systemic symptoms from the disease itself or due to adverse effect of this treatment. This contributes to the increasing number of reports that rituximab can be an effective treatment for refractory ocular complications of rheumatoid arthritis (RA), at least as an induction therapy.

Reduced Myxobolus cerebralis actinospore production in a Colorado reservoir may be linked to changes in Tubifex tubifex population structure.

Elucidating the dynamics of a parasitic infection requiring two hosts in a natural ecosystem can be a daunting task. Myxobolus cerebralis (Mc), the myxozoan parasite that causes whirling disease in some salmonids, was detected in the Colorado River upstream of Windy Gap Reservoir (WGR) in 1988. Subsequently, whirling disease was implicated in the decline of wild Rainbow Trout Oncorhynchus mykiss in the river when WGR was identified as a point source of Mc triactinomyxons (TAMs). Between 1997 and 2004, numerous investigations began to elucidate the etiology of Mc in WGR. During this period, Mc TAM production in WGR declined more than 90%. Explanations for the decline have included differences in stream discharge between years, changes in the thermal regime of the lake, severe drought, changes in the fish population structure in WGR, and reductions in the prevalence and severity of Mc infection in salmonids in the Colorado and Fraser rivers upstream of WGR. All of these have been discredited as explanations for the reduced TAM production. In 2005, a new study was conducted to replicate the studies completed in 1998. In this paper, the results of a new real-time polymerase chain reaction assay utilized to quantify the mitochondrial 16S rDNA specific to each of four lineages of Tubifex tubifex in pooled samples of 50 oligochaetes are presented. These results suggest that compared with 1998, the densities of aquatic oligochaetes and T. tubifex have increased, TAM production has been greatly reduced, and the decline is congruent with the dominance of lineages I, V, and VI of T. tubifex-three lineages that are refractory or highly resistant to Mc infection-in the oligochaete population. While it is possible that the resistant lineages function as biofilters that deactivate Mc myxospores, the reason for the decline in TAM production in WGR remains an enigma.

[Anterior segment analysis using OCT3]. / Méthodologie d'analyse du segment antérieur par OCT-3.

PURPOSE: Optical coherence tomography has been used for many years, in particular in the field of the retinal imaging, and is a promising technique in the analysis of the anterior segment, providing a similar resolution to histology for ocular tissue. MATERIAL AND METHODS: We present a collection of images obtained with the OCT3 (Carl Zeiss Meditec, Dublin, CA), with parameters set to obtain good-quality images of the iris and corneal structures. RESULTS: The OCT provides detailed analysis of the cornea, precise assessment of the dimensions and locations of corneal lesions - in the anterior-posterior plane as well as transversally or obliquely - with 10-microm precision, and the study of the iridocorneal angle and its dynamics. DISCUSSION: Using the highly precise OCT3 for retinal imaging, it is possible to obtain good-quality anterior segment imaging, which makes the device highly versatile and thus increases reasons for acquiring this type of apparatus. CONCLUSIONS: OCT3 users should not neglect this potential of the device, already in wide use for examining the retina.

[Femtosecond-assisted anterior lamellar keratoplasty]. / Kératoplastie lamellaire antérieure assistée par laser femtoseconde.

INTRODUCTION: Automated lamellar keratoplasty remains a challenging surgical technique because of surgical difficulties and is associated with a high rate of complications. The precision of the corneal cut at any corneal depth with the femtosecond laser is an important improvement in this technique. We report the first case of femtosecond-assisted anterior lamellar keratoplasty. MATERIAL AND METHODS: A 63-year-old woman with anterior stromal dystrophy underwent femtosecond laser-assisted ALTK on the left eye. A donor lenticula was prepared from a corneoscleral rim utilizing the Femtec 20/10 Perfectvision femtosecond laser device and an artificial anterior chamber (Moria, Antony, France). The anterior lamellar cut was also performed on the patient's eye with the femtosecond laser. RESULTS: Postoperative examinations showed a well-adapted graft with a clear interface. OCT III (Carl Zeiss Meditech, Dublin) measurements showed a corneal pachymetry of 713 microm associated with a regular posterior bed and a central thickness of 132 microm. DISCUSSION: Femtosecond laser corneal cutting may offer greater safety, reproducibility, predictability, and flexibility. The risks of irregular cutting and microperforation are reduced. A better graft congruence can limit the risk of secondary displacement and the smooth interface should improve visual results. CONCLUSION: Donor lenticulae and corneal cuttings performed with the Femtec 20/10 Perfectvision( femtosecond laser device can be used in the successful management of eyes requiring anterior lamellar keratoplasty. Further studies are needed to evaluate outcomes of this procedure.

Evidence for changing of cosmic ray composition between 10(17) and 10(18) eV from multicomponent measurements

The average mass composition of cosmic rays with primary energies between 10(17) and 10(18) eV has been studied using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype and the MIA muon array. Measurements have been made of the change in the depth of shower maximum and the muon density as a function of energy. The results show that the composition is changing from a heavy to lighter mix as the energy increases.

A Rapid X-ray Flare from Markarian 501.

We present X-ray observations of the BL Lacertae object Mrk 501 that were taken with the Rossi X-Ray Timing Explorer in 1998 May as part of a multiwavelength campaign. The X-ray light curve shows a very rapid flare in which the 2-10 keV flux increased by approximately 60% in less than 200 s. This rapid rise is followed by a drop-off in the 2-10 keV flux of approximately 40% in less than 600 s. The 10-15 keV variation in this flare is roughly a factor of 2 on similar timescales. During the rise of the flare, the 3-15 keV spectral index hardened from 2.02+/-0.03 to 1.87+/-0.04, where it remained during the decay of the flare. This is the fastest variation ever seen in X-rays from Mrk 501 and among the fastest seen at any wavelength for this object. The shift in the energy at which the spectral power peaks (from less, similar3 keV before the flare to greater, similar30 keV during the flare) is also among the most rapid shifts seen from this object. This flare occurs during an emission state (2-10 keV flux approximately 1.2x10-10 ergs cm-2 s-1) that is approximately 25% of the peak flux observed in 1997 April from this object but that is still high compared to its historical average X-ray flux. The variations in the hardness ratio are consistent with the low-energy variations leading those at high energies during the development and decay of the flare. This pattern is rare among high-frequency peaked BL Lac objects like Mrk 501, but has been seen recently in two other TeV-emitting BL Lac objects, Mrk 421 and PKS 2155-304. The hard lag is consistent with a flare dominated by the acceleration timescale for a simple relativistic shock model of flaring.

Simultaneous X-Ray and TeV Observations of a Rapid Flare from Markarian 421.

Mrk 421 was observed for about 2 days with BeppoSAX in 1998 April as part of a worldwide multiwavelength campaign. A large, well-defined flare was observed in X-rays. The same flare was observed simultaneously at TeV energies by the Whipple Observatory gamma-ray telescope. These data provide (1) the first evidence that the X-ray and TeV intensities are well correlated on timescales of hours and (2) the first exactly simultaneous X-ray and TeV spectra. The results imply that the X-ray and TeV photons derive from the same region and from the same population of relativistic electrons. The physical parameters deduced from a homogeneous synchrotron self-Compton model for the spectral energy distribution yield electron cooling times close to the observed variability timescales.