Engineering dissipation with phononic spectral hole burning.

Optomechanics, nano-electromechanics, and integrated photonics have brought about a renaissance in phononic device physics and technology. Central to this advance are devices and materials supporting ultra-long-lived photonic and phononic excitations that enable novel regimes of classical and quantum dynamics based on tailorable photon-phonon coupling. Silica-based devices have been at the forefront of such innovations for their ability to support optical excitations persisting for nearly 1 billion cycles, and for their low optical nonlinearity. While acoustic phonon modes can persist for a similar number of cycles in crystalline solids at cryogenic temperatures, it has not been possible to achieve such performance in silica, as silica becomes acoustically opaque at low temperatures. We demonstrate that these intrinsic forms of phonon dissipation are greatly reduced (by >90%) by nonlinear saturation using continuous drive fields of disparate frequencies. The result is a form of steady-state phononic spectral hole burning that produces a wideband transparency window with optically generated phonon fields of modest (nW) powers. We developed a simple model that explains both dissipative and dispersive changes produced by phononic saturation. Our studies, conducted in a microscale device, represent an important step towards engineerable phonon dynamics on demand and the use of glasses as low-loss phononic media.

Apoptosis as a Mechanism for Keratinocyte Death in Canine Toxic Epidermal Necrolysis.

In humans and dogs, toxic epidermal necrolysis (TEN) is a life-threatening dermatosis characterized by sudden epidermal death resulting in extensive skin detachment. There is little information on the pathogenesis of keratinocyte cell death in canine TEN. We studied the occurrence of apoptosis in skin lesions of dogs with TEN to determine if apoptosis contributes to the pathogenesis of this disease. Immunostaining with antibodies to activated caspase-3 and the terminal deoxynucleotidyl-transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling technique revealed positive apoptotic keratinocytes in basal and suprabasal epidermal compartments in 17 biopsy specimens collected from 3 dogs with TEN and 16 from 3 dogs with erythema multiforme (EM). There was no significant difference in the number of positively stained epidermal cells between TEN and EM. These results suggest that apoptosis of epidermal keratinocytes and lymphocytic satellitosis represent one of the early steps in the pathogenesis of canine TEN, as in the human disease counterpart.

Cytologic Criteria for Mast Cell Tumor Grading in Dogs With Evaluation of Clinical Outcome.

A 2-tiered histologic grading scheme for canine cutaneous mast cell tumors (MCTs) is based on morphologic characteristics of neoplastic cells, including karyomegaly, multinucleation, nuclear pleomorphism, and mitotic figures. Aspirates from MCTs may provide the same information more quickly, inexpensively, and less invasively. This study used these criteria to develop a cytologic grading scheme for canine MCTs to predict outcome. Three anatomic pathologists graded histologic samples from 152 canine MCTs. Three clinical pathologists evaluated aspirates from these masses using similar criteria. A cytologic grading scheme was created based on correlation with histologic grade and evaluated with a kappa statistic. Survival was evaluated with Kaplan-Meier survival curves. Cox proportional hazards regression was used to estimate hazard ratios for tumor grades and individual grading components. Simple logistic regression tested for relationships between risk factors and mortality. The cytologic grading scheme that best correlated with histology (kappa = 0.725 ± 0.085) classified a tumor as high grade if it was poorly granulated or had at least 2 of 4 findings: mitotic figures, binucleated or multinucleated cells, nuclear pleomorphism, or >50% anisokaryosis. The cytologic grading scheme had 88% sensitivity and 94% specificity relative to histologic grading. Dogs with histologic and cytologic high grade MCTs were 39 times and 25 times more likely to die within the 2-year follow-up period, respectively, than dogs with low grade MCTs. High tumor grade was associated with increased probability of additional tumors or tumor regrowth. This study concluded that cytologic grade is a useful predictor for treatment planning and prognostication.

Multimaterial piezoelectric fibres.

Fibre materials span a broad range of applications ranging from simple textile yarns to complex modern fibre-optic communication systems. Throughout their history, a key premise has remained essentially unchanged: fibres are static devices, incapable of controllably changing their properties over a wide range of frequencies. A number of approaches to realizing time-dependent variations in fibres have emerged, including refractive index modulation, nonlinear optical mechanisms in silica glass fibres and electroactively modulated polymer fibres. These approaches have been limited primarily because of the inert nature of traditional glassy fibre materials. Here we report the composition of a phase internal to a composite fibre structure that is simultaneously crystalline and non-centrosymmetric. A ferroelectric polymer layer of 30 mum thickness is spatially confined and electrically contacted by internal viscous electrodes and encapsulated in an insulating polymer cladding hundreds of micrometres in diameter. The structure is thermally drawn in its entirety from a macroscopic preform, yielding tens of metres of piezoelectric fibre. The fibres show a piezoelectric response and acoustic transduction from kilohertz to megahertz frequencies. A single-fibre electrically driven device containing a high-quality-factor Fabry-Perot optical resonator and a piezoelectric transducer is fabricated and measured.

Comparison of CO(2) laser and 4.0 MHz radiosurgery for making incisions in the skin and muscles of green iguanas (Iguana iguana).

Four green iguanas scheduled for euthanasia were used to compare the extent of collateral tissue damage associated with CO(2) laser and 4.0 MHz radiosurgery. The iguanas were anaesthetised and a series of three skin and three muscle incisions was made by 4.0 MHz radiosurgery (0.18 mm wire electrode, 25 W, cut mode) and CO(2) laser (0.3 mm ceramic tip, 15 W focused beam super-pulse mode), and three incisions were made with a scalpel blade as controls. Following euthanasia, a total of 60 skin and 36 muscle sections were evaluated histologically. Radiosurgery and the laser both produced bloodless incisions, but radiosurgery caused significantly less collateral tissue damage in the skin (307 [97] v 386 [108] microm) and the muscle (18 [7] v 91 [15] microm).

Variation among pathologists in the histologic grading of canine cutaneous mast cell tumors with uniform use of a single grading reference.

Ten veterinary pathologists independently assigned histologic grades to the same 60 canine cutaneous mast cell tumors using the Patnaik classifications. The degree of agreement in grading among the pathologists was compared with the degree of agreement among the same pathologists in a previous study, in which each pathologist used the reference for grading that he/she uses routinely. Mean agreement improved significantly from 50.3% to 62.1% with uniform use of the Patnaik classifications (P = 0.00001), suggesting that there is value in uniform application of a single grading scheme for canine cutaneous mast cell tumors. Agreement among pathologists was still not 100%, suggesting that a more objective grading scheme should be developed and that other histologic indicators of prognosis should be investigated.

Responses of red foxes to first and second infection with Sarcoptes scabiei.

The clinical response of red foxes (Vulpes vulpes) to the mange mite, Sarcoptes scabiei, was characterized by infection of five, 4-mo-old red foxes with S. scabiei originally isolated from a wild red fox. The infected foxes and three uninfected control foxes were monitored with weekly complete blood counts and biweekly serum chemistry profiles, hypersensitivity tests, and evaluation of skin biopsies. After 7 wk, the foxes were treated and held free of infection for 2 mo. Six foxes, three previously infected and three with no history of exposure, were then infected with the same isolate of S. scabiei and followed for another 7 wk; two additional previously infected foxes were held as treatment controls, and two foxes with no history of exposure as naive controls. All infected foxes developed significant immediate (Type I) hypersensitivity reactions to a S. scabiei mite extract within 2 wk of exposure and maintained this reaction as long as 4 mo after clearance of mites. Pronounced mast cell hyperplasia and infiltration with eosinophils were the earliest inflammatory cell responses noted in biopsy samples from infected foxes and were maintained throughout infection. Infected foxes also showed significant increases in white blood cell counts, due primarily to increases in numbers of circulating neutrophils and eosinophils. Clinical response, severity of disease, and relative numbers of mites per cm2 of skin of previously infected foxes and foxes undergoing their first infection did not differ. These results show that red foxes develop strong immediate hypersensitivity reactions to S. scabiei but, under our experimental conditions, did not exhibit resistance to reinfection.

Diseases diagnosed in red foxes from the southeastern United States.

Diagnostic findings on 51 red foxes (Vulpes vulpes) from the southeastern United States examined from 1967 to 1995 were reviewed. Etiologic diagnoses included sarcoptic manage (n = 33), traumatic injury and associated complications (n = 5), suspected canine distemper (n = 2), capture myopathy (n = 1), congenital absence of guard hairs (n = 1), intradermal tick infestation (n = 1), otodectic manage (n = 1), and toxicosis (n = 1). The cause of morbidity was not determined for three of the foxes, and three others were classified as normal animals. Sarcoptic manage was diagnosed in 65% of the red foxes, was found in foxes submitted from four of the eight southeastern states represented, and was seen in 19 of 29 yr covered by this study.

Trombidiosis-induced dermatitis in white-tailed deer (Odocoileus virginianus).

During a routine blood collection at a wildlife management checkpoint, several white-tailed deer (Odocoileus virginianus) from Lake Russell Wildlife Management Area, Habersham County, Georgia, were observed to have accumulations of orange granular material around the eyes and mouth accompanied by serous exudate, crusting, and alopecia. Microscopic examination of the granular material disclosed numerous larval mites of the family Trombiculidae. Histologic examination revealed severe chronic diffuse plasmacytic dermatitis with intralesional larval trombiculid mites. Several stylostomes were also identified in the tissue sections. This paper describes the gross and histologic changes associated with severe trombiculid infestation in a white-tailed deer and suggests potential causes for this unusual finding.

Treatment of localized Mycobacterium avium complex infection with clofazimine and doxycycline in a cat.

Mycobacterium avium complex infection resulted in a granuloma that developed at the base of the left ear in a cat. The lesion caused vestibular dysfunction and facial palsy on the left side and protruded into the oral cavity on that side. The cat was treated successfully, with resolution of the lesion and elimination of the organism, by use of combined administration of clofazimine and doxycycline. Adverse effects of the clofazimine treatment included temporary reddish-orange discoloration of the cat's skin and mucous membranes.

Rapid tissue expansion for the development of rotational skin flaps in the distal portion of the hindlimb of dogs: an experimental study.

In phase I, tissue expanders were implanted subcutaneously over the lateral crural region of four dogs. The expanders were inflated daily to maintain a constant intraluminal pressure for 7 days. All animals tolerated the pressurized expanders well. Some animal patient discomfort was associated with repeated injections into the subcutaneous filling port. One dog developed a limited area of tissue loss and exposure of the expander. Tissue response to the expanders included epidermal hyperplasia, dermal collagen compression with early fibroplasia, and subcutaneous granulation tissue formation adjacent to the expander pocket. In phase II, a second group of four dogs underwent rapid skin expansion over 7 days. The pressure applied to the expanding skin was determined daily and adjusted to approximate the value reported for capillary pressure in the dog. Tissue discoloration occurred in two dogs, suggestive of impaired circulation. Skin flaps were developed from expanded skin and rotated over the talocrural region. Wound dehiscence occurred along the distal flap margin in three phase II dogs. These wounds healed by second intention. Branches of the caudal saphenous artery were identified, using angiography, as the primary blood supply to the skin flaps.

Clinical and histologic characterization of cutaneous reactions to stings of the imported fire ant (Solenopsis invicta) in dogs.

Four adult dogs received experimentally controlled stings in the dorsolateral abdominal skin by imported fire ants (Solenopsis invicta). The sites were examined grossly 15 minutes and at 1, 2, 3, 4, 5, 6, 24, 48, and 72 hours and histologically 15 minutes and 6, 24, 48, and 72 hours after stinging. The initial gross lesions at 15 minutes were swelling and erythema, and the microscopic changes were vascular congestion and superficial dermal edema. By 6 hours, the lesions consisted of bright erythematous pruritic papules characterized microscopically by a band of full thickness dermal necrosis and inflammation. By 24 hours and continuing to the end of the study at 72 hours, the sites appeared completely normal grossly. Biopsies taken 24, 48, and 72 hours after stings contained microscopic changes similar to those present at 6 hours after stings. These histologic changes are unlike those described for human beings stung by imported fire ants. In human beings, fire ant stings are characterized histologically by an initial superficial vesicle that evolves into a sterile pustule.

Cryptosporidiosis in four cockatoos with psittacine beak and feather disease.

Cryptosporidiosis was diagnosed in 4 cockatoos with psittacine beak and feather disease. Three of the birds had cryptosporidiosis confined to the epithelium covering the bursa of Fabricius. One bird had generalized parasitism of the small intestine, large intestine, and bursal epithelium. All of the birds had intermittent to protracted diarrhea before death. Presumably, acquired immunodeficiency from psittacine beak and feather disease promoted establishment of cryptosporidiosis and other secondary diseases including septicemia, peritonitis, chlamydiosis, and mycotic ventriculitis.

Comparison of procedures for assessing adequacy of dog foods.

Dog foods with similar claims for nutritional adequacy were tested by chemical analysis and the American Association of Feed Control Officials' growth trial. All foods tested were similar chemically, however, dogs given one regionally marketed food had lower growth rate and food efficiency as well as suboptimal PCV and hemoglobin values during the growth trial. Pups fed this diet also had clinical signs typical of zinc and copper deficiencies. We concluded that American Association of Feed Control Officials' approved feeding tests provide valid assessment of pet food quality, and procedures involving only chemical analysis or calculated values may not.

A novel DNA virus associated with feather inclusions in psittacine beak and feather disease.

The nature of feather inclusions was characterized in 32 psittacine birds (30 cockatoos, one peach-faced lovebird (Agapornis roseicollis), and one red-lored Amazon parrot (Amazona autumnalis autumnalis] with naturally-acquired psittacine beak and feather disease. Intranuclear inclusions within feather epithelial cells and intracytoplasmic inclusions within macrophages in the feather epithelium and pulp cavity contained psittacine beak and feather disease viral antigen when stained by the avidin-biotin complex immunoperoxidase technique. Ultrastructurally, inclusions were observed primarily within macrophages and to a lesser extent within epithelial cell nuclei. Macrophage inclusions appeared as paracrystalline arrays of viral particles. Intranuclear inclusions were less well defined, although scattered viral particles were present. Intracytoplasmic and intranuclear particles in ultrastructural preparations were identified by colloidal gold labeling as psittacine beak and feather disease virus. Feather epithelium was more frequently and severely involved in the disease process than was adjacent follicular epithelium. Plucked feathers with an intact epidermal collar and feather epithelium were preferred to follicular biopsies for histopathologic examination.

Plasma, tissue, and urine carnitine concentrations in healthy adult cats and kittens.

Mean carnitine concentrations [( carnitine]) were higher (P less than 0.05) in adult cats than in kittens for skeletal muscle (total and free carnitine), myocardium (free carnitine), and urine (total and free carnitine). The free/total carnitine ratio was lower (P less than 0.05) in kittens than in adults for liver, myocardium, and urine. Carnitine concentrations were similar between genders in kittens, but in adult cats, [carnitine] in plasma (total, free, and esterified carnitine) and liver (total and free carnitine) were higher (P less than 0.05) in female than in male cats. Total and free plasma [carnitine] were correlated to total and free liver [carnitine], respectively. Skeletal muscle [carnitine] was not correlated to plasma [carnitine]. Correlations in [carnitine] between plasma and myocardium, kidney, or urine were inconsistent.

Comparison of plasma, liver, and skeletal muscle carnitine concentrations in cats with idiopathic hepatic lipidosis and in healthy cats.

Concentrations of total, free, and esterified carnitine were determined in plasma, liver, and skeletal muscle from cats with idiopathic hepatic lipidosis and compared with values from healthy cats. The mean concentrations of plasma, liver, and skeletal muscle total carnitine; plasma and skeletal muscle free carnitine; and plasma and liver esterified carnitine were greater (P less than 0.05) in cats with idiopathic hepatic lipidosis than in control cats. The mean for the ratio of free/total carnitine in plasma and liver was lower (P less than 0.05) in cats with idiopathic hepatic lipidosis than in control cats. These data suggest that carnitine deficiency does not contribute to the pathogenesis of feline idiopathic hepatic lipidosis.

Evaluation of ketoconazole and itraconazole for treatment of disseminated cryptococcosis in cats.

During the first part of a study, cats were inoculated with Cryptococcus neoformans via the following routes: intradermal, intranasal, IV, and intracisternal. Only use of the IV route of inoculation consistently induced disseminated cryptococcosis. In the second part of the study, disseminated cryptococcosis was experimentally induced in cats via IV inoculation of C neoformans. One month after inoculation, 3 cats were treated with ketoconazole (10 mg/kg of body weight/d) and 3 cats were treated with itraconazole (10 mg/kg/d) for 3 months. One of the ketoconazole-treated and 2 of the itraconazole-treated cats also had cryptococcosis of the CNS when treatment was begun. During treatment, serum cryptococcal antigen titer progressively decreased in all cats. Abnormalities in CBC values or the serum biochemical profile were not found in any cat during treatment. However, all ketoconazole-treated cats became anorectic and lost weight. Side effects were not seen in itraconazole-treated cats. During the 3-month posttreatment observation period, all cats remained healthy. At necropsy, histologic evidence of cryptococcosis was not found in the 3 ketoconazole-treated cats or in 2 of the itraconazole-treated cats. In the third itraconazole-treated cat, cryptococcal organisms were found in the kidneys.