A case of lipogranulomatous conjunctivitis in a horse.

OBJECTIVE: To describe a case of lipogranulomatous conjunctivitis in a horse. ANIMAL STUDIED: A client-owned 12-year-old Standardbred gelding presenting with chronic conjunctivitis and palpebral masses. METHODS: Complete ophthalmic examination, surgical excision, histopathology, and bacterial culture of biopsy samples were performed. RESULTS: Upper and lower eyelids of both eyes were affected, with multiple yellow-to-white nodules on the palpebral conjunctiva, adjacent to the eyelid margin. Nodule removal was achieved via partial tarsal plate excision. Histopathological examination revealed granulomatous inflammation and large droplets of presumed free lipid in the conjunctival lamina propria. The animal was diagnosed with lipogranulomatous conjunctivitis. No postoperative ocular discomfort was observed for months; however, 3 years later, new conjunctival nodules were noticed, requiring a second surgical procedure on three of the eyelids. Transient entropion in the left lower eyelid was observed 2 months after the second surgery, and no recurrence of conjunctival nodules was observed after 18 months of follow-up. CONCLUSION: To our knowledge, this is the first report of lipogranulomatous conjunctivitis in horses.

[Long-term follow-up of a multimodally managed pulmonary mucoepidermoid carcinoma in a cat]. / Langzeitstudie einer multimodalen Behandlung eines mukoepidermoiden Lungenkarzinoms bei einer Katze.

INTRODUCTION: The present case describes the treatment of a mucoepidermoid carcinoma in a 13-year-old female sterilized European domestic cat, using lung lobectomy and -accompanying mitoxantrone chemotherapy. Six, 14, 19 and 27 months after the initial treatment tomodensitometric and radiographic examinations showed no abnormalities. However, the cat had to be euthanized 27 months after the lung lobectomy due to a soft tissue sarcoma in the interscapular area.

INTRODUCTION: Ce cas décrit un carcinome mucoépidermoïde chez un chat européen femelle stérilisée de 13 ans, entité non rapportée jusqu'alors chez cette espèce, pris en charge par lobectomie pulmonaire et chimiothérapie adjuvante avec de la mitoxantrone. L'examen tomodensitométrique et les clichés radiographiques, réalisés respectivement 6 mois, 14, 19 mois, et 27 mois après la chirurgie, ne mettaient en évidence aucune anomalie. Cependant, vingt-sept mois après l'intervention chirurgicale, une euthanasie est réalisée suite à l'aggravation en quelques mois d'un sarcome des tissus mous en région inter-scapulaire.

Leiomyoma in the nasal cavity of a dog.

A 7-year-old, 34-kg, neutered male Labrador retriever was presented with a 1-year history of intermittent sneezing with occasional left-sided epistaxis. CT revealed a mass in the left nasal cavity. Histopathological analysis of rhinoscopy-guided tissue biopsies was consistent with chronic necrotic and ulcerative rhinitis. Surgical debridement by ventral rhinotomy was subsequently performed and histopathological diagnosis was leiomyoma. Complete resolution of the nasal discharge and reduced sneezing frequency were observed after surgery. Fourteen months postoperatively, CT detected no regrowth of the mass.

RACK1 cooperates with NRASQ61K to promote melanoma in vivo.

Melanoma is the deadliest skin cancer. RACK1 (Receptor for activated protein kinase C) protein was proposed as a biological marker of melanoma in human and domestic animal species harboring spontaneous melanomas. As a scaffold protein, RACK1 is able to coordinate the interaction of key signaling molecules implicated in both physiological cellular functions and tumorigenesis. A role for RACK1 in rewiring ERK and JNK signaling pathways in melanoma cell lines had been proposed. Here, we used a genetic approach to test this hypothesis in vivo in the mouse. We show that Rack1 knock-down in the mouse melanoma cell line B16 reduces invasiveness and induces cell differentiation. We have developed the first mouse model for RACK1 gain of function, Tyr::Rack1-HA transgenic mice, targeting RACK1 to melanocytes in vivo. RACK1 overexpression was not sufficient to initiate melanomas despite activated ERK and AKT. However, in a context of melanoma predisposition, RACK1 overexpression reduced latency and increased incidence and metastatic rate. In primary melanoma cells from Tyr::Rack1-HA, Tyr::NRasQ61K mice, activated JNK (c-Jun N-terminal kinase) and activated STAT3 (signal transducer and activator of transcription 3) acted as RACK1 oncogenic partners in tumoral progression. A sequential and coordinated activation of ERK, JNK and STAT3 with RACK1 is shown to accelerate aggressive melanoma development in vivo.

Comparison of 3 Handling Techniques for Endoscopically Obtained Gastric and Duodenal Biopsy Specimens: A Prospective Study in Dogs and Cats.

BACKGROUND: Limited evidence exists in the literature regarding whether a specific mount is preferable to use for processing endoscopically obtained gastrointestinal biopsy specimens. HYPOTHESIS/OBJECTIVES: To compare 3 methods of handling endoscopically obtained gastrointestinal biopsy specimens from collection to laboratory processing and to determine if any technique produced superior results. ANIMALS: Twenty-three dogs and cats presented for gastrointestinal signs. METHODS: Prospective study of dogs and cats presented with gastrointestinal signs to a veterinary teaching referral hospital which underwent upper gastrointestinal endoscopy. Biopsy specimens were taken from the stomach and duodenum and submitted to the laboratory using 3 techniques: mounted on a cucumber slice, mounted on a moisturized synthetic foam sponge, and floating free in formalin. The techniques were compared with regard to the specimens' width, orientation, presence of artifacts, and pathologist's confidence in diagnosis. RESULTS: Twenty-three patients were included, with a total of 528 biopsies collected. Specimens on cucumber slice and on sponge were significantly wider (P < .001 and P = .001, respectively) compared to those floating free in formalin (mean width of 3.81 versus 3.31 and 2.52 mm, respectively). However, specimens on synthetic sponge had significantly fewer artifacts compared to those on cucumber slice (P = .05) and those floating free in formalin (P = .02). Confidence in the diagnosis also was superior with the sponge technique over floating free specimens (P = .002). CONCLUSIONS AND CLINICAL IMPORTANCE: The use of mounted gastrointestinal biopsy specimens was superior over the use of specimens floating free in formalin. This technique improved the quality of the specimens and the pathologist's confidence in their histopathologic interpretation.

Non-Bragg-gap solitons in one-dimensional Kerr-metamaterial Fibonacci heterostructures.

A detailed study of non-Bragg-gap solitons in one-dimensional Kerr-metamaterial quasiperiodic Fibonacci heterostructures is performed. The transmission coefficient is numerically obtained by combining the transfer-matrix formalism in the metamaterial layers with a numerical solution of the nonlinear differential equation in the Kerr slabs, and by considering the loss effects in the metamaterial slabs. A switching from states of no transparency in the linear regime to high-transparency states in the nonlinear regime is observed for both zero-order and plasmon-polariton gaps. The spatial localization of the non-Bragg-gap solitons is also examined, and the symmetry properties of the soliton waves are briefly discussed.

Metric-signature topological transitions in dispersive metamaterials.

The metric signature topological transitions associated with the propagation of electromagnetic waves in a dispersive metamaterial with frequency-dependent and anisotropic dielectric and magnetic responses are examined in the present work. The components of the reciprocal-space metric tensor depend upon both the electric permittivity and magnetic permeability of the metamaterial, which are taken as Drude-like dispersive models. A thorough study of the frequency dependence of the metric tensor is presented which leads to the possibility of topological transitions of the isofrequency surface determining the wave dynamics inside the medium, to a diverging photonic density of states at some range of frequencies, and to the existence of large wave vectors' modes propagating through the metamaterial.

Endogenous endophthalmitis caused by Enterococcus faecalis in a cat.

A three-year-old male neutered domestic shorthair cat was presented for loss of vision associated with hyperthermia, lethargy and anorexia. Ophthalmic examination revealed a bilateral panuveitis. Cytological examination of aqueous and vitreous humours was performed and revealed a suppurative inflammation associated with numerous cocci. Enterococcus faecalis was identified by bacterial culture from aqueous and vitreous humour. No primary infection site was identified. Active uveitis resolved after systemic antibiotic therapy, but the vision loss was permanent. To the authors' knowledge, this is the first reported case of endogenous bacterial endophthalmitis secondary to E. faecalis infection in a cat.

Omnidirectional suppression of Anderson localization of light in disordered one-dimensional photonic superlattices.

The omnidirectional suppression of Anderson localization of light in a disordered one-dimensional normal-metamaterial photonic superlattice is thoroughly investigated. Analytical conditions relating to the electric-permittivity and magnetic-permeability responses of each slab of the heterostructure are established for the omnidirectional divergence of the localization length of the normal-metamaterial superlattice. The robustness of such conditions with respect to the degree of disorder of the superlattice is also analyzed.

Subclinical leishmaniasis associated with infertility and chronic prostatitis in a dog.

A stud dog was presented for acquired infertility. Haematospermia and teratozoospermia were found on two ejaculates 2 weeks apart. A presumptive diagnosis of prostatitis was made follo-wing ultrasound examination. An ultrasound-guided needle core biopsy was performed under general anaesthesia, revealing a mild chronic macrophagic and plasma cell prostatitis with intracytoplasmic amastigotes consistent with Leishmania spp. infection. Presence of Leishmania infantum, Leishmania donovani or Leishmania chagasi was confirmed by polymerase chain reaction in seminal plasma. Serology and serum protein electrophoresis confirmed the diagnosis of a subclinical active systemic leishmaniasis. A meglumine antimoniate and allopurinol treatment was given which clearly improved within 3 months both general condition and the quality of sperm. To the authors' knowledge, this is the first reported case of a prostatitis secondary to a Leishmania spp. infection. Subclinical systemic leishmaniasis should be considered in the differential diagnosis of infertility in dogs suffering from semen alterations.

[A case of feline leishmaniasis in the south of France]. / Un cas de leishmaniose féline disséminée dans le sud de la France.

We report a case of disseminated feline leishmaniasis in a FIV-seropositive 14-year-old male cat (Felis catus) living in the Alpes-Maritimes (south of France). The cat presented with erythematous ulcerated papules on the head and withers, and with an ulcerated proliferative lesion on the left pinnae. The condition was diagnosed, along with a squamous cell carcinoma of the pinnae, after histopathological examination of the cutaneous lesions. Total remission of the cutaneous lesions was obtained after oral administration of 100 mg of allopurinol once a day for four months. Necropsic samples revealed that the parasite was still present in the organism after six months of treatment. This case discusses of the cat sensibility to the leishmaniasis pathology and of his potential ability of being a reservoir host.

Field profiles of bulk plasmon polariton modes in layered systems containing a metamaterial.

Electric and magnetic fields in a one-dimensional layered system that alternates air and a metamaterial are investigated. Special attention is devoted to frequencies of electric and magnetic bulk plasmons. It is shown that plasmon polaritons nearby such frequencies display field profiles concentrated in the metamaterial, where the field component parallel to the stacking direction is essentially uniform and dominates the perpendicular one.

Anderson localization and Brewster anomalies in photonic disordered quasiperiodic lattices.

A comprehensive study of the properties of light propagation through one-dimensional photonic disordered quasiperiodic superlattices, composed of alternating layers with random thicknesses of air and a dispersive metamaterial, is theoretically performed. The superlattices consist of the successive stacking of N quasiperiodic Fibonacci or Thue-Morse heterostructures. The width of the slabs in the photonic superlattice may randomly fluctuate around its mean value, which introduces a structural disorder into the system. It is assumed that the left-handed layers have a Drude-type dispersive response for both the dielectric permittivity and magnetic permeability, and Maxwell's equations are solved for oblique incidence by using the transfer-matrix formalism. The influence of both quasiperiodicity and structural disorder on the localization length and Brewster anomalies are thoroughly discussed.

Zero-(n) non-Bragg gap plasmon-polariton modes and omni-reflectance in 1D metamaterial photonic superlattices.

A theoretical study of the photonic band structure and transmission spectra for 1D periodic superlattices with an elementary cell composed of two layers of refractive indices n(a) and n(b), which may take on positive as well as negative values, has been performed within the transfer-matrix approach. The dependence on the angle of incidence of the electromagnetic wave for excitation of plasmon-polaritons as well as the properties of the (n) = 0 gap were thoroughly investigated. Results are found for the generalized conditions that must be satisfied by the ratio a/b of the layer widths of metamaterial photonic superlattices, for both transverse electric and transverse magnetic polarizations, in order to have an omnidirectional (n) = 0 gap. The present study indicates new perspectives in the design and development of future optical devices.

Plasmon polaritons in photonic metamaterial superlattices: absorption effects.

We discuss the propagation of electromagnetic waves in layered structures made up of alternate layers of air and metamaterials. The role played by absorption on the existence of electric and magnetic plasmon polaritons is investigated. Results show that plasmon-polariton modes are robust even in the presence of rather large absorption.

Chronic traumatic brain injury in a dog.

Chronic traumatic brain injury is rare in man and has not been previously documented in dogs. This report describes a 2-year-old female American Staffordshire bull terrier that was referred with forelimb and hindlimb ataxia, decreased vigilance and disorientation following repeated aggression and physical abuse by its owner. A diffuse cortical lesion was suspected. Cerebrospinal fluid analysis revealed neutrophilic pleocytosis and computed tomography showed marked widening of the cerebral sulci with mild bilateral ventriculomegaly. The dog was humanely destroyed in view of the poor prognosis. Necropsy examination revealed narrowing of the cerebral cortical gyri and consequent widening of the sulci without distortion or displacement of the neural parenchyma. These features were consistent with bilateral diffuse cortical atrophy. Microscopically, there were chronic subarachnoid haemorrhages and the cortical subpial layer displayed spongiosis, capillary hyperplasia, astrocytosis, microgliosis and frequent neuronal necrosis occurring in a characteristic laminar pattern. This histopathological pattern of damage was significantly different from that previously described in people suffering from repeated traumatic brain injuries over a long period of time.

Laser-dressing and magnetic-field effects on shallow-donor impurity states in semiconductor GaAs-Ga(1-x)Al(x)As cylindrical quantum-well wires.

The influence of an intense laser field on shallow-donor states in cylindrical GaAs-Ga(1-x)Al(x)As quantum-well wires under an external magnetic field applied along the wire axis is theoretically studied. Numerical calculations are performed in the framework of the effective-mass approximation, and the impurity energies corresponding to the ground state and 2p(±) excited states are obtained via a variational procedure. The laser-field effects on the shallow-donor states are considered within the extended dressed-atom approach, which allows one to treat the problem 'impurity + heterostructure + laser field + magnetic field' as a renormalized 'impurity + heterostructure + magnetic field' problem, in which the laser effects are taken into account through a renormalization of both the conduction-band effective mass and fundamental semiconductor gap.

Absorption effects on plasmon polaritons in quasiperiodic photonic superlattices containing a metamaterial.

Absorption effects on plasmon-polariton excitations in quasiperiodic (Fibonacci and Thue-Morse) one-dimensional stacks composed of layers of right- and left-handed materials are theoretically investigated. A Drude-type dispersive response for both the dielectric permittivity and magnetic permeability of the left-handed layer is considered. Maxwell's equations are solved for oblique incidence by using the transfer matrix formalism, and the reflection coefficient as a function of the frequency and incidence angle is obtained. The Fibonacci (or Thue-Morse) quasiperiodic structure leads to a Cantor-like photonic spectra for the plasmon-polariton modes. Moreover, results for the photonic band structure, density of states and reflection coefficient indicate that plasmon-polariton modes are robust in the presence of low and moderate levels of absorption.

Effects of hydrostatic pressure on the electron [Formula: see text] factor and g-factor anisotropy in GaAs-(Ga, Al)As quantum wells under magnetic fields.

The hydrostatic-pressure effects on the electron-effective Landé [Formula: see text] factor and g-factor anisotropy in semiconductor GaAs-Ga(1-x)Al(x)As quantum wells under magnetic fields are studied. The [Formula: see text] factor is computed by considering the non-parabolicity and anisotropy of the conduction band through the Ogg-McCombe effective Hamiltonian, and numerical results are displayed as functions of the applied hydrostatic pressure, magnetic fields, and quantum-well widths. Good agreement between theoretical results and experimental measurements in GaAs-(Ga, Al)As quantum wells for the electron g factor and g-factor anisotropy at low values of the applied magnetic field and in the absence of hydrostatic pressure is obtained. Present results open up new possibilities for manipulating the electron-effective g factor in semiconductor heterostructures.

Photonic band structure and symmetry properties of electromagnetic modes in photonic crystals.

Within the Maxwell framework and using a transfer-matrix technique we have determined a general equation which governs the photonic band structure and the density of states of one-dimensional superlattices composed of two alternate layers characterized by different refractive indexes, which may take on positive as well as negative values. Besides the usual well-known results, we have found null-gap points for commensurate values of the optical path lengths of each layer. Furthermore, we have been able to characterize non-Bragg gaps that show up in frequency regions in which the average refractive index is null.