Lasing in strained germanium microbridges.

Germanium has long been regarded as a promising laser material for silicon based opto-electronics. It is CMOS-compatible and has a favourable band structure, which can be tuned by strain or alloying with Sn to become direct, as it was found to be required for interband semiconductor lasers. Here, we report lasing in the mid-infrared region (from λ = 3.20 µm up to λ = 3.66 µm) in tensile strained Ge microbridges uniaxially loaded above 5.4% up to 5.9% upon optical pumping, with a differential quantum efficiency close to 100% with a lower bound of 50% and a maximal operating temperature of 100 K. We also demonstrate the effect of a non-equilibrium electron distribution in k-space which reveals the importance of directness for lasing. With these achievements the strained Ge approach is shown to compare well to GeSn, in particular in terms of efficiency.

Proteolytic activity of gut bacteria isolated from the velvet bean caterpillar Anticarsia gemmatalis.

The development of proteinase inhibitors as potential insect control agents has been constrained by insect adaptation to these compounds. The velvet bean caterpillar (Anticarsia gemmatalis) is a key soybean pest species that is well-adapted to proteinase inhibitors, particularly serine-proteinase inhibitors, which are abundant in the caterpillar host. The expression of diverse proteolytic enzymes by gut symbionts may allow the velvet bean caterpillar to circumvent proteinase inhibitors produced by the host plant. In this study, we characterized the proteolytic activity of the four nonpathogenic species of gut bacteria isolated from the velvet bean caterpillar-Bacillus cereus, Enterococcus gallinarum, Enterococcus mundtii and Staphylococcus xylosus. Two proteinase substrates, N-α-benzoyl-L-Arg-p-nitroanilide (L-BApNA) and N-α-p-tosyl-L-Arg methyl ester (L-TAME) and five proteinase inhibitors [aprotinin, E-64, ethylenediamine tetraacetic acid (EDTA), pepstatin and N-α-tosyl-L-lysine chloromethyl ketone (TLCK)] as well as CaCl2, pH and temperature profiles were used to characterize the expressed proteolytic activity of these bacterial strains in vitro. Kinetic parameters for proteolytic activity were also estimated. The results of these experiments indicated that serine- and cysteine-proteinase activities were expressed by all four gut bacteria symbionts of the velvet bean caterpillar. The cysteine- and serine-proteinase activities of these gut symbionts were distinct and different from that of gut proteinases of the caterpillar itself. This finding provides support for the potential involvement of gut symbionts in the mitigation of the negative effects of serine-proteinase inhibitors in the velvet bean caterpillar.

Plasma lipids and inflammation in active inflammatory bowel diseases.

BACKGROUND: Ulcerative colitis (UC) and Crohn's disease (CD) can cause metabolic and inflammatory alterations. AIM: To evaluate the relationships between inflammatory parameters, plasma lipids and phospholipid fatty acid (FA) composition in patients with active UC and CD. METHODS: Diet, the Harvey-Bradshaw Activity Index (HBAI), inflammatory parameters, lipoproteins and FA composition were assessed in 60 CD and 34 UC. RESULTS: No differences in clinical parameters were observed in the two groups. Total cholesterol correlated inversely with the number of bowel movements in both groups and directly with BMI in UC. Arachidonic acid correlated inversely with HBAI in UC and total and HDL cholesterol were inversely related to C-reactive protein (CRP) in CD while HDL correlated with CRP in UC. Docosapentaenoic acid was the only polyunsaturated n-3 FA that was correlated to CRP in both groups. Total cholesterol was independently associated in the multiple regression analysis with the number of bowel movements and systemic inflammation. CONCLUSIONS: Total and LDL cholesterol were lower in the active UC and CD than in the healthy subjects and were correlated with the systemic inflammatory status. Phospholipid FA composition was correlated to the systemic inflammatory status, but was unrelated to dietary intake and intestinal disease activity.

Morphological and functional modifications of the aneurysm-endograft complex following endoluminal treatment of abdominal aortic aneurysms.

PURPOSE: The aim of the study was to evaluate quantitatively the main morphological changes of the abdominal aortic aneurysm (AAA)-endograft (EG) complex following endovascular repair of infrarenal AAA and to evaluate the functional consequences of these changes in terms of rate of complications (endoleaks and thrombosis). We also assessed whether these morphological and functional changes were related to the size of the AAA and to the type of EG used. MATERIALS AND METHODS: Eighty-five patients (M/F=82/3; mean age at time of operation 70.5+/-3.5 years, range 49.9-89.6 years) who underwent endovascular treatment of infrarenal AAA between April 1997 and October 2004 with a follow-up of at least 1 month were considered. All images of 408 preoperative and postoperative computed tomography (CT) studies were reviewed. Statistical analysis was performed with log-rank test on the 85 patients grouped according to AAA diameter <50 mm or < or =50 mm, and on 75 patients grouped according to EG device used (AneuRx, Talent or Excluder). RESULTS: Morphological and dimensional changes involved the diameter (six cases) and length (14 cases) of AAA proximal neck, diameter (36 cases) and length (51 cases) of the aneurysm sac and shape of the stent-graft (47 cases). The prevalence of endoleaks was 37.6% whereas endoluminal thrombosis was observed in 27.1% of patients. AAA growth was significantly correlated (p=0.002) with the preprocedural diameter of the aneurysm sac whereas shrinkage was significantly correlated (p=0.0005) with the EG used. CONCLUSIONS: AAA growth was correlated with the diameter of the aneurysm sac while shrinkage was correlated with the EG used. During follow-up after endovascular repair, patients require careful evaluation of the morphological and dimensional features of the AAA and EG to promptly identify any changes that can anticipate major complications and even conversion to conventional surgery.

Polishing-induced contamination of fused silica optics and laser induced damage density at 351 nm.

In this paper we study the effect of contamination induced by fabrication process on laser damage density of fused silica polished parts at 351 nm in nanosecond regime. We show, owing to recent developments of our raster scan metrology, that a good correlation exists between damage density and concentration of certain contaminants for the considered parts.

[Solitary fibrous tumor of the orbit: an unusual cause of unilateral proptosis. Case report with a review of the literature]. / Tumeur fibreuse solitaire de l'orbite: une cause inhabituelle d'exophtalmie unilatérale. A propos d'un cas avec revue de la littérature.

BACKGROUND: The solitary fibrous tumor (SFT) is a spindle-cell tumor that very rarely involves the orbit. We report a new case that we compare to reports in the literature. CASE: A 72-year-old woman presented a conjunctival inflammation of the right eye developing over 5 months with progressive proptosis. Magnetic resonance imaging revealed an extraconal and homogeneous mass, which showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images, without specificity. Histological examination of the lesion removed by anterior orbitotomy confirmed the diagnosis of the SFT of the orbit. The patient was doing well without recurrence after 9 months. DISCUSSION: The diagnosis of SFT is histological. It is a mesenchymal tumor. Immunohistochemically, the tumor cells are strongly positive for CD34 and vimentin. CONCLUSION: The SFT of the orbit is a very rare and generally benign tumor. It must be immunohistochemically differentiated from other spindle-cell tumors of the orbit. The treatment is a complete surgical excision, and long-term follow-up is necessary because recurrence may appear long after treatment.

[Ocular tolerance of a new formulation of nonpreserved diclofenac]. / Intérêt d'une nouvelle formulation de diclofénac sans conservateur pour la surface oculaire.

AIM: To compare the ocular tolerance of nonpreserved diclofenac versus thiomersal-preserved diclofenac in healthy volunteers. MATERIALS AND METHODS: Forty healthy volunteers instilled Dicloabak in the randomised eye and thiomersal-preserved diclofenac in the other eye, according to a strictly identical dosing regimen, for 28 days. Each volunteer thus served as his or her own control. The dose regimen was five drops/day for 7 days followed by three drops/day for 20 days. Ocular tolerance was assessed by the discomfort upon instillation (measured on a visual analogue scale [VAS]), subjective ocular symptoms following instillation (irritation/burning/stinging, eye dryness and foreign body sensation) and finally by an objective examination of the ocular surface. These criteria were evaluated on days 0, 14, 21 and 28. RESULTS: The subjective ocular symptoms following instillation were significantly lower in the nonpreserved group at Day 7 and nearly significantly lower until the end of the study. The biomicroscopy exam confirmed that there was better tolerance without thiomersal. There was less follicular-papillary conjunctivitis and a significantly better lissamine green score in the Dicloabak group. CONCLUSION: The results of this study demonstrate that the nonpreserved formulation of diclofenac is better tolerated by the ocular surface and thus constitutes a therapeutic benefit.

[Phototherapeutic keratectomy in the treatment of lattice corneal dystrophy type I]. / La photokératectomie thérapeutique dans le traitement de la dystrophie grillagée de type I.

PURPOSE: Lattice corneal dystrophy type I is an autosomal dominant corneal dystrophy caused by allelic mutations of the BIGH3 gene. Type I dystrophy is recognized clinically by the characteristic net of linear opacities within the corneal stroma that results from an accumulation of amyloid. This study was designed to evaluate the therapeutic potential of phototherapeutic keratectomy (PTK) for the treatment of lattice corneal dystrophy type I. PATIENTS AND METHODS: PTK was performed with the Chiron Technolas Chiron Keracor 217c on a series of 19 eyes of 13 patients with lattice dystrophy type I. Mean patient age was 38.9 years. The mean follow-up period was 36 months. Localization of central opacities was determined by analyzing Scheimpflug images. The changes in spherical equivalent and best corrected visual acuity were evaluated at 1, 3, 6, 9, 12, 18, 24 and 36 months. RESULTS: The central depth of the deposits measured with the Scheimpflug camera was on average 74.14+/-31.03 microm in the primary dystrophies and 30.1+/-10 microm in graft recurrence. We noted a clear improvement in visual acuity, which increased by 0.257+/-0.120 to 0.600+/-0.178 as of the 3rd month and stabilized at 0.684+/-0.257 until the 36th month. A disappearance of repeating ulcerations was observed at month 30. We found a statistically significant correlation (R=0.6776; p=0.0109) between the improvement in vision (in lines) and the depth of opacities (with the Scheimpflug camera). The mean hyperopic shift caused by photoablation (69+/-15 microm) was +0.71+/-1 D at 36 months. CONCLUSION: These results confirm that PTK is an effective method of managing corneal lattice dystrophy type I.

[Early recurrence of Groenouw type I corneal dystrophy after phototherapeutic keratectomy. Molecular biology study suggests epithelial genesis]. / Récidive d'une dystrophie de Groenouw de type I après photokératectomie thérapeutique. Etude en biologie moléculaire du rôle de l'épithélium cornéen.

PURPOSE: Granular corneal dystrophy Groenouw type 1 (GGI) is a rare autosomal dominant disease caused by allelic mutations of the BIGH3 gene. The specific phenotype is characterized by granular opacities (white, sharply demarcated spots resembling bread crumbs) in corneal stroma, which cause recurrent corneal erosions and blurred vision. Phototherapeutic keratectomy (PTK) is an effective procedure that improves visual acuity, but recurrences are unavoidable. Though GGI deposits are well described, their origin is not completely known. The production of mutated keratoepithelin protein (a product of the BIGH3 gene) is the first step necessary for deposits to appear. Molecular biology experiments were conducted to determine the role of corneal cell types in the genesis of early recurrent deposits of post-PTK GGI. METHODS: Tissue specimens from a patient undergoing penetrating keratoplasty for recurrence of GGI (12 months after PTK) and five normal corneas were examined by hybridization in situ and immunohistology to study the expression of BIGH3 and location of keratoepithelin. RESULTS: Only one healthy cornea expressed BIGH3 mainly in the epithelium and less in keratinocytes and endothelial cells. In the GGI corneas, BIGH3 was highly expressed in the modified, hyperplastic epithelium. The keratoepithelin was accumulated under the epithelium where deposits were formed. CONCLUSION: This observation confirms that corneal epithelium is the main producer of mutated keratoepithelin on the cellular scale and thus constitutes the principal source of dystrophic deposit formation during recurrence.

[Implantation of preserved human amniotic membrane for the treatment of shield ulcers and persistent corneal epithelial defects in chronic allergic keratoconjunctivitis]. / Greffe de membrane amniotique et traitement des ulcères de cornée lors des kératoconjonctivites chroniques allergiques.

PURPOSE: To determine whether amniotic membrane implantation is a safe and effective alternative treatment for shield ulcers and persistent corneal epithelial defects associated with ulcers in chronic allergic keratoconjunctivitis (vernal or atopic keratoconjunctivitis). METHODS: Amniotic membrane implantation was performed in four consecutive patients with persistent corneal epithelial defects or vernal plaques unresponsive to conventional medical treatment lasting an average of 18 weeks. Surgery was done under general anesthesia using amniotic membrane as a therapeutic contact lens. RESULTS: A significant decrease in symptoms and complete reepithelialization of the corneal ulcers were observed in all cases within the first 7 days. These remained stable during a mean follow-up of 12 weeks, with no intraoperative or postoperative complications. Early detachment occurred in all cases with no negative consequences on ulcer healing. CONCLUSION: Patients with severe chronic allergic keratoconjunctivitis derive benefits from amniotic membrane implantation used as a therapeutic contact lens in the treatment of persistent corneal epithelial defects and vernal plaques unresponsive to conventional medical treatment.

[Treatment of conjunctival epithelial tumors: brachytherapy with ruthenium-106]. / Traitement des tumeurs épithéliales de la conjonctive: intérêt de la curiethérapie au ruthénium-106.

INTRODUCTION: Treatment of conjunctival epithelial tumors is not standardized because it is difficult to compare large series in this rare disease. Surgical excision is usual, but the recurrence rate has led several authors to propose alternative therapies. PATIENTS AND METHODS: During the past 20 years, brachytherapy using ophthalmic applicators has been developed and the results of different studies have confirmed the usefulness of this therapy. We report a retrospective study of 13 patients presenting with a conjunctival epithelial tumor treated with ruthenium106 applicators and followed up in our department since 1987. RESULTS AND CONCLUSION: There was no recurrence during a mean follow-up of 48 months. Complications depended on the size of the area treated and the dose of radiation.

[Bilateral uveitis with definitive hypotony caused by systemic cidofovir]. / Uvéite bilatérale et hypotonie définitive due au cidofovir intraveineux. A propos d'un cas.

We report the case of a 52-year-old man with AIDS and CMV bilateral retinitis, treated first with ganciclovir (cymevan) and then with cidofovir. During the treatment, the patient complained of a sharp decrease in visual acuity. Cycloplegics and topical corticosteroids were given. Then cidofovir was stopped and replaced with intravenous Foscavir because of the clinical inefficacy. The anterior uveitis resolved but the ciliary secretion has not stopped after 12 months of follow-up. The patient presented +11 hypermetropia with a choroidal edema and bilateral cataract. This case is interesting for its permanent hypotony and bilateral uveitis. A literature search has brought out a rate of only 3% of chronic hypotony. We hypothesize bilateral iatrogenic ciliary body necrosis, as described in the animal models.

Bone formation in hydroxyapatite tricalcium phosphate ceramic implants used in the treatment of the postenucleation socket syndrome.

PURPOSE: To determine the histopathologic changes in coralline hydroxyapatite tricalcium phosphate (HA-TCP) blocks used in the treatment of the postenucleation socket syndrome (PESS). METHODS: Twenty-four patients were treated with HA-TCP blocks placed directly into the orbital fat to correct the PESS. Eight of these patients required partial removal of the material for various reasons between 32 and 371 days after the initial operation. The orbital implants were decalcified and processed for light and electron microscopic examination. RESULTS: Light microscopy demonstrated fibrovascular ingrowth into the pores of the implant in all cases. Osteogenesis was observed in three cases in the periphery of the implant. Ossification occurred in the implants after a mean implantation duration of 276 days versus 67 days in cases without ossification. CONCLUSION: Implants of HA-TCP, a new material used in ophthalmology, demonstrate the presence of fibrovascular ingrowth, reflecting the excellent biointegration of this material.

Anterior coracoscapular ligament and suprascapular nerve entrapment.

A reduction in the height of the suprascapular foramen may predispose to entrapment of the suprascapular nerve. In this study, 16 of 27 cadavers (60%) demonstrated a heretofore unreported ligament located on the anterior aspect of the suprascapular foramen. In 11 of the 27 cadavers (41%), the ligament was observed bilaterally. The ligament decreased the foraminal height from the normative value of 5.6 +/- 0.4 to 2.3 +/- 0.4 mm (mean +/- SEM). Because this ligament, for which we propose the term anterior coracoscapular ligament (ACSL), substantially narrows the suprascapular foramen, it should be considered as a possible etiologic factor in suprascapular nerve entrapment.

[Definitive internal tamponade with silicone oil in certain cases of retinal detachment]. / Tamponnement interne définitif par huile de silicone dans certains cas de décollement de rétine.

PURPOSE: The aim of this study was to analyze the effect of definitively maintaining silicone oil in the treatment of certain cases of retinal detachment. MATERIAL AND METHODS: Sixteen cases of retinal detachment seen from July 1995 to April 1999 were retrospectively studied. For these eyes with residual visual acuity, we voluntarily maintained silicone oil. There were 11 men and 5 women, mean age 56 (range 24 - 82). Followup ranged from 18 to 45 months. RESULTS: We analyzed visual acuity outcome, complications, and main reasons for maintaining longterm silicone oil CONCLUSION: This study provided interesting insight concerning certain clinical situations where silicone oil has to be maintained definitively. In some cases, low, but useful, visual acuity can be achieved for long periods of time. This therapeutic approach would be particularly helpful for mono-ophthalmic patients.

[Lacrimal sac cyst: apropos of a case]. / Kyste du sac lacrymal: à propos d'un cas.

A 17-year-old girl presented a unilateral cyst of the lacrimal sac. Epiphora was induced by compression of the patent lacrimal duct. The bony nasolacrimal canal was enlarged on the affected side. At pathology examination, the epithelium of the cyst wall was identical to the sac epithelium.