Biomedical subjects

R A Rosychuk

Publications and source records attributed to R A Rosychuk.

At least 19 recordsLinked to original sources

PubMed2001

Clinicopathologic findings, sensitivity to house dust mites and efficacy of milbemycin oxime treatment of dogs with Cheyletiella sp. infestation.

Twenty-three dogs with positive skin scrapings for Cheyletiella sp. were treated with milbemycin oxime using a protocol approximating 2 mg kg-1 orally once weekly for three weeks. Nineteen of these dogs belonged to a household of 41 dogs and two dogs were in households with one other dog. All in-contact dogs were treated. Pre-treatment intradermal skin tests showed positive reactions to D. farinae in 13 dogs and to D. pteronyssinus in 12 dogs; these became negative post-treatment in four and seven dogs, respectively. All dogs showed a dramatic reduction in clinical signs one week after the third treatment. Eighteen dogs no longer had mites on skin scrapings, three had dead mites and two had deformed eggs. Recurrence of clinical signs necessitated two additional courses of the protocol in the multiple dog household and for a dog receiving immunosuppressive treatment for pemphigus foliaceus. Possible adverse reactions to the milbemycin (vomiting, lethargy) were noted once in two dogs.

Animals↗

PubMed2001

Zinc-responsive dermatosis in dogs: 41 cases and literature review.

Forty-one cases of zinc-responsive dermatosis in the dog are described. The Siberian husky was the predominant breed affected. Periocular crusts were the most common clinical sign and parakeratosis was noted in the skin biopsy specimens of all dogs. Treatment with oral zinc ameliorated the clinical signs in most dogs, but cases necessitating other treatments such as parenteral zinc or retinoids are reported. The authors recommend a starting dose of 2-3 mg kg-1 elemental zinc per day in the treatment of this disorder.

Administration, Oral↗

PubMed1998

Pharmacokinetics of exogenous corticotropin in normal dogs, hospitalized dogs with non adrenal illness and adrenopathic dogs.

Corticotropin (ACTH) pharmacokinetics was assessed in 10 normal dogs receiving exogenous ACTH (0.5 U/kg, i.v.). A two-compartment open model was most appropriate for description of exogenous ACTH pharmacokinetics. The apparent distribution and elimination rate constants (alpha and beta) were 7.4 +/- 2.7 x 10(-2) min(-1) and 5.5 +/- 3.8 x 10(-3) min(-1), respectively. Area under the concentration-time curve (AUC) was 2.91 +/- 0.78 x 10(4) pg x min/mL, mean residence time (MRT) was 45.0 +/- 12.2 min, the distribution half-life (t1/2alpha) was 9.4 min (harmonic mean), and the elimination half-life (t1/2beta) was 128 min (harmonic mean). The total body clearance of ACTH (ClB) was 1.83 +/- 0.46 x 10(4) mL x min/kg and volume of distribution (Vd(area)) was 30 +/- 15 L/kg. Corticotropin pharmacokinetics was also assessed in 12 client owned dogs, six dogs with non adrenal illness (NAI) and six dogs with hyperadrenocorticism (HAC), receiving exogenous ACTH (0.5 U/kg, i.v.). For these patients, data was best fitted to a one-compartment open model. In dogs with NAI, the AUC was 6.23 +/- 0.62 x 10(5) pg x min/mL, MRT was 38.7 +/- 12 min, the apparent elimination rate constant (k(el)) was 0.26 +/- 0.0017 min(-1) elimination half-life was 26.7 min, ClB was 0.84 +/- 0.1 x 10(4) mL/min/kg, and Vd(area) was 31.9 +/- 5.7 L/kg. In dogs with HAC, AUC was 4.74 +/- 0.23 x 10(5) pg x min/mL, MRT was 20.4 min, k(el) was 0.034 +/- 0.009 min(-1), half-life was 20.4 min, CIB was 1.06 +/- 6.0 x 10(4) mL/min/kg and Vd(area) was 29.7 +/- 6.7 L/kg. Dogs with pituitary-dependent hyperadrenocorticism showed more rapid elimination and clearance of exogenous corticotropin than dogs with NAI.

Adrenal Cortex Diseases↗

PubMed1995

Sebaceous adenitis in dogs and results of treatment with isotretinoin and etretinate: 30 cases (1990-1994).

Medical records of 30 dogs with histologically confirmed sebaceous adenitis that were treated with isotretinoin or etretinate were reviewed. Akitas and Standard Poodles were overrepresented, compared with the general hospital population. Thirteen dogs had concurrent pyoderma. The retinoids were administered for a minimum of 2 months. Dosage for the 13 dogs treated with isotretinoin only ranged from 0.8 to 3.5 mg/kg of body weight/d (mean, 1.4 mg/kg/d). Dosage for the 10 dogs treated with etretinate only ranged from 0.7 to 1.8 mg/kg/d (mean, 1.1 mg/kg/d). Two dogs were first given isotretinoin (mean dosage, 1.5 mg/kg/d) and, when they did not respond, were subsequently given etretinate (mean dosage, 0.85 mg/kg/d). Five dogs were first given etretinate (mean dosage, 1 mg/kg/d) and, when they did not respond, were subsequently given isotretinoin (mean dosage, 1.6 mg/kg/d). For the 20 dogs treated with isotretinoin, 1 was lost to follow-up; 9 of the remaining 19 had a successful outcome (> 50% reduction in severity of scaling and extent of alopecia, compared with pretreatment appearance). For the 17 dogs treated with etretinate, 9 had a successful outcome. Outcome could not be predicted on the basis of clinical signs or histologic findings, and a prognosis could not be determined on the basis of whether sebaceous glands were evident histologically.

Alopecia↗

PubMed1994

Management of otitis externa.

Otitis externa represents one of the most common reasons that pets are presented for veterinary attention. They are also some of the more frustrating entities practitioners are called on to deal with. Successful management depends on an understanding of the primary, predisposing, and perpetuating factors involved in the pathogenesis of otitis externa. Emphasis is then placed on establishing a diagnosis through physical examination, cytologic examination, culture and sensitivity testing, radiographs and biopsies. The general goals of management are to resolve, remove, or control primary factors, clean and dry the ear, reduce inflammation and resolve secondary infections. These goals are achieved through various cleaning techniques, topical, and systemic therapies. Therapeutic alternatives are given for otitis involving bacteria, Malassezia, otodectes, demodex, allergies, ceruminous disorders, the idiopathic inflammatory/hyperplastic otitis externa of cocker spaniels, "Swimmer's Ear", contact/irritant reactions, overtreatment, and concurrent otitis media.

Animals↗

PubMed1994

Llama dermatology.

The purpose of this article is to add information to the many dermatologic topics initially discussed in the 1989 issue on llama medicine (normal anatomy; bacterial, fungal, ectoparasitic, immune-mediated, and zinc-responsive disease) and make mention of newly recognized diseases. Since 1989, it appears that one of the most common and perplexing groups of dermatoses seen at Colorado State University are hyperkeratotic/inflammatory dermatoses. These remain poorly understood. Idiopathic hyperkeratosis (zinc-responsive dermatosis) may be a true zinc deficiency or a keratinizing disorder responsive to supraphysiologic dosages of zinc supplementation. Idiopathic nasal/perioral hyperkeratotic/ inflammatory dermatosis (munge) and idiopathic necrolytic/neutrophilic/hyperkeratotic dermatosis bear clinical, histologic, and therapeutic similarities, and may be subsets of the same disease. Further studies (e.g., looking for metabolic derangements) are necessary to better answer these questions.

Animals↗

PubMed1993

Use of isotretinoin and etretinate for the treatment of benign cutaneous neoplasia and cutaneous lymphoma in dogs.

The purpose of this study was to evaluate the synthetic retinoids isotretinoin and etretinate to treat dogs with intracutaneous cornifying epitheliomas (ICE), other benign skin neoplasias, and cutaneous lymphoma. Twenty-four dogs were used. All tumors were diagnosed by histologic examination. Ten dogs with multiple (at least 5) benign skin tumors (7 with ICE, 1 each with inverted papillomas, sebaceous adenomas and epidermal cysts) were treated with isotretinoin (n = 7) and/or etretinate (n = 5). Twelve dogs with cutaneous lymphoma were treated with isotretinoin, and 2 dogs with cutaneous lymphoma were initially treated with etretinate. Successful treatment with isotretinoin was achieved in 1 dog with ICE, 1 with inverted papillomas, and 1 with epidermal cysts. Partial improvement with isotretinoin was seen in 2 dogs with ICE. Successful treatment was achieved with etretinate in 4 dogs with ICE (Norwegian Elkhound was the predominant breed with ICE). Remission was achieved in 6 of the 14 dogs with cutaneous lymphoma. Adverse effects developed in 7 of the 24 dogs, so treatment was stopped in 2 dogs.

Animals↗

PubMed1993

Feline gingivitis-stomatitis-pharyngitis.

Inflammatory conditions of the feline mouth are commonly encountered in small animal practice. Although the majority can be attributed to dental disease and a small percentage are due to autoimmune diseases, the eosinophilic granuloma complex, neoplasia, and other miscellaneous syndromes, many cases appear to be due to a gingivitis-stomatitis-pharyngitis complex, which is likely multifactorial in origin. Viruses, bacterial infection, diet, dental disease, oral conformation, genetic predisposition, hypersensitivities, immunoinsufficiencies, and other defects in oral defense mechanisms may all be contributory. The complexities of this syndrome have made it one of the most challenging diagnostic and therapeutic problems in feline medicine.

Animals↗

PubMed1992

Use of tetracycline and niacinamide for treatment of autoimmune skin disease in 31 dogs.

A combination of niacinamide and tetracycline was used to treat 31 dogs with various autoimmune skin diseases (discoid lupus erythematosus, pemphigus foliaceus, pemphigus erythematosus, and bullous pemphigoid). Of the 20 dogs with discoid lupus erythematosus, 70% had excellent or good response to treatment. Serious side effects were not noticed in any dog.

Animals↗

PubMed1992

Plasma cell stomatitis-pharyngitis in cats: 40 cases (1973-1991).

Clinical signs, laboratory findings, and treatment results of 40 cats with the histologic diagnosis of plasma cell stomatitis-pharyngitis are discussed. Median age was 7.1 years, with no discernable sex predilection. Anorexia and difficulty prehending food were the most common clinical signs. Hyperproteinemia with associated hyperglobulinemia was the most common laboratory finding. Of various treatments, administration of corticosteroids or injectable gold (aurothioglucose) proved most effective in controlling the clinical signs.

Adrenal Cortex Hormones↗

PubMed1992

Investigation of antibodies to extractable nuclear antigens in dogs.

Determination of antibodies to specific nuclear antigens, termed extractable nuclear antigen (ENA), was investigated in healthy dogs and in dogs with autoimmune, inflammatory, and neoplastic diseases. Using a counterimmunoelectrophoresis method, the dogs' sera were tested for antibodies against the nuclear antigens single-stranded DNA, Sm, Ro, La, ribonucleoprotein, Scl, and proliferating cell nuclear antigen. Antibodies to the Ro antigen were found in 1 dog with discoid lupus erythematosus, in 1 dog with pemphigus erythematosus, and in 1 dog with facial pyoderma and chronic superficial keratitis. In 15 dogs, antibodies were detected to ENA, but the precipitin lines were too weak to identify the specific ENA. These antibodies were found in some dogs with systemic lupus erythematosus, discoid lupus erythematosus, pemphigus erythematosus, dermatomyositis, vitiligo, lymphoma; in the dog with facial pyoderma and chronic superficial keratitis; and in 1 healthy dog. The highest percentage of dogs with antibodies to ENA in a large series (greater than 8) of this study was in dogs with systemic lupus erythematosus (4 of 13; 31%).

Animals↗

PubMed1990

Effects of flunixin and flunixin plus prednisone on the gastrointestinal tract of dogs.

Flunixin meglumine has been reported to induce gastrointestinal lesions in dogs when administered at therapeutic dosages. We administered flunixin meglumine to dogs daily for 10 days to assess the effect of this drug on the gastrointestinal tract. We also evaluated the possibility of corticosteroid potentiation of gastrointestinal toxicosis by concurrent administration of prednisone to 1 group of dogs. Dogs were monitored for gastrointestinal toxicosis by means of serial endoscopic evaluation, measurement of fecal occult blood, PCV, and total solid concentration, and by physical examination. There were 3 treatment groups of 5 dogs each. Group-1 dogs were given 2.2 mg of flunixin meglumine/kg daily, in 2 divided doses IM; group-2 dogs were given 4.4 mg of flunixin meglumine/kg daily, in 2 divided doses IM; and group-3 dogs were given 2.2 mg of flunixin meglumine/kg daily, in 2 divided doses IM plus 1.1 mg of prednisone/kg/d orally, in 2 divided doses. A fourth group of 5 dogs served as a control group. Endoscopically visible gastric mucosal lesions developed in all treated dogs within 4 days of initiating treatment. Lesions first developed in the gastric pylorus and antrum and lesions at these sites were more severe than those observed elsewhere. Dogs treated with flunixin meglumine plus prednisone developed the earliest and most severe lesions; lesion scores in group-2 dogs were higher than those in group-1 dogs. All dogs treated had occult blood in their feces by day 5 and its presence appeared to correlate more closely with endoscopic findings than did physical examination findings or changes in values for PCV or total solids.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Juvenile cellulitis in dogs: 15 cases (1979-1988).

The records of 15 dogs diagnosed as having juvenile cellulitis (juvenile pyoderma, puppy strangles) were evaluated for clinical, laboratory, and therapeutic results. Mandibular lymphadenopathy was observed in 14 dogs, and was not associated with skin lesions in 5 dogs. Edema, pustules, papules, or crusts were noticed periorally, periocularly, on the chin or muzzle, or in the ears of those dogs with skin lesions. Eight dogs were lethargic; fever and anorexia were inconsistent findings. Four dogs had signs of pain on manipulation of their joints. Complete blood counts revealed leukocytosis with neutrophilia in 4 dogs, and normocytic, normochromic anemia in 6 dogs. Three dogs had suppurative lymphadenitis with many neutrophils. Cytology of the aspirate of pustules or abscesses in 6 dogs revealed many neutrophils without bacteria. Coagulase-positive Staphylococcus spp were isolated from draining lesions in 2 dogs. Intact abscesses and lymph nodes were negative for bacterial growth in 4 dogs. Three of these dogs were being administered antibiotics at the time of bacterial culturing. Cytology of the aspirates of joints in 3 of the 4 dogs with joint pain revealed suppurative arthritis with no bacteria, and the aspirates were negative for bacterial growth on culturing, although all 3 dogs were being administered antibiotics at the time of culturing. Of 12 dogs initially treated with antibiotics, only 4 (33%) responded favorably; the other 8 dogs were then given antibiotics and corticosteroids. Three dogs were initially given antibiotics and corticosteroids. All dogs treated concurrently with antibiotics and corticosteroids responded favorably. One of these dogs had a relapse after treatment was discontinued. The concurrent arthritis in 4 of the dogs resolved with treatment of the juvenile cellulitis and did not redevelop once the medication was discontinued. Concurrent treatment with antibiotics (cephalosporins) and prednisone (2.2 mg/kg of body weight/day) was the most consistently effective treatment in the dogs in this study.

Adrenal Cortex Hormones↗

PubMed1989

Pulmonary thromboembolism associated with immune-mediated hemolytic anemia in dogs: ten cases (1982-1987).

Pulmonary thromboembolism was confirmed at necropsy in 10 (32.2%) of 31 dogs treated for immune-mediated hemolytic anemia. Radiographic findings associated with thromboembolism included pronounced interstitial lung pattern and small amounts of pleural effusion. Variables associated with significantly higher incidence of pulmonary thromboembolism included hyperbilirubinemia (P = 0.023), negative Coombs test result (P = 0.032), and presence of an indwelling catheter (P = 0.04). There was a tendency (P = 0.06) for association of higher number of whole blood transfusions with pulmonary thromboembolism.

Anemia, Hemolytic, Autoimmune↗

PubMed1989

Llama dermatology.

As llamas become more common in North America, veterinarians will be called on ever more frequently to deal with their dermatologic problems. Adherence to the basic tenets of the thorough dermatologic work up, including history, physical examination, skin scrapings, cytological examinations, fungal culture, skin biopsies, and assessing response to judiciously chosen trial therapies will offer the best opportunity of arriving at proper diagnoses. Special attention must be paid to the fact that llama skin bears some histological differences that may prove confusing to the uninitiated. A mild degree of hyperkeratosis, a prominent vascular plexus in the superficial dermis that is associated with mild perivascular mononuclear cell accumulations, and regional differences in sebaceous gland size and numbers, all are considered normal findings. Ectoparasites, including sarcoptic mange, chorioptic manage, and pediculosis, appear to be the most common causes of pruritus in the llama. Although ivermectin therapy would appear to be very effective for the treatment of scabies and, indeed, may work well against sucking lice, chorioptic mange and biting lice usually do not respond to this medication. Corticosteroids can be used to treat pruritus in the llama nonspecifically, using the anti-inflammatory dosages established in other species. These drugs are used most appropriately for the management of the allergies that we suspect occur in this species, until better alternative therapies can be developed. Variably pruritic focal areas of alopecia, exudation, and crusting suggest differential diagnoses including bacterial folliculitis and furunculosis, dermatophilosis, dermatophytosis, and coccidioimycosis. The diagnosis of bacterial problems often is made by assessing response to antibiotic therapy. Topical disinfectants and/or systemic penicillin or trimethoprim-sulfadiazine are indicated. Dermatophilosis is treated by cleaning and drying the leasions, applying topical antibiotics, and, occasionally, using parenteral penicillin and streptomycin. Dermatophytosis usually is treated with topical antibiotics only. Captan is one of several therapies of choice. There is no therapy presently available for coccidioidomycosis in the llama. Perhaps most perplexing is the fact that one of the most common dermatopathies seen in the llama is an idiopathic keratinizing disorder that, in some cases, is responsive to zinc supplementation. We have no real idea of the pathogenesis of this problem and recognize that some affected animals will not respond to supplementation.(ABSTRACT TRUNCATED AT 400 WORDS)

Alopecia↗

PubMed1988

Perianal adenomas and hypertestosteronemia in a spayed bitch with pituitary-dependent hyperadrenocorticism.

Hypertestosteronemia was diagnosed in a spayed bitch with pituitary-dependent hyperadrenocorticism and perianal adenomas. Serum concentrations of cortisol and testosterone decreased after treatment with mitotane was instituted. Excessive testosterone in this dog was thought to have been produced by the adrenal cortex, possibly in response to excessive ACTH concentrations. Development of androgen- or estrogen-responsive tumors in castrated dogs may be an early indication of adrenocortical hyperfunction.

Adenoma↗

PubMed1988

Endocrine, metabolic, internal, and neoplastic causes of pruritus in the dog and cat.

Many of the etiologies of pruritus presented herein have been discussed with a view to promoting an awareness of less common causes of pruritus in the dog and cat. For those differential diagnoses that have as yet not been described in our companion animals, the purpose is to stimulate us to look. Of particular interest are the diseases that may cause pruritus without obvious cutaneous pathology. In these instances, the challenge is to make the association. To this end, Table 1 lists those differential diagnoses that would be considered in human beings who have generalized pruritus unassociated with significant cutaneous pathology. Those diseases described to date in the dog and cat have been identified.

Animals↗

PubMed1988

Serum concentrations of thyroxine and 3,5,3'-triiodothyronine in dogs before and after administration of freshly reconstituted or previously frozen thyrotropin-releasing hormone.

Concentrations of serum thyroxine (T4) and 3,5,3'-triiodothyronine (T3) were determined after the administration of freshly reconstituted thyrotropin-releasing hormone (TRH), reconstituted TRH that had been previously frozen, or thyrotropin (TSH) to 10 mature dogs (6 Greyhounds and 4 mixed-breed dogs). Thyrotropin-releasing hormone (0.1 mg/kg) or TSH (5 U/dog) was administered IV; venous blood samples were collected before and 6 hours after administration of TRH or TSH. Concentrations of the T4 and T3 were similar (P greater than 0.05) in serum after administration of freshly reconstituted or previously frozen TRH, indicating that TRH can be frozen at -20 C for at least 1 week without a loss in potency. Concentrations of T4, but not T3, were higher after the administration of TSH than they were after the administration of TRH (P less than 0.01). Concentrations of T4 increased at least 3-fold in all 10 dogs given TSH, whereas a 3-fold increase occurred in 7 of 10 dogs given freshly reconstituted or previously frozen TRH. Concentrations of T4 did not double in 1 dog given freshly reconstituted TRH and in 1 dog given previously frozen TRH. Concentrations of T3 doubled in 5 of 10, 2 of 10, and 5 of 10 dogs given TSH, freshly reconstituted TRH, or previously frozen TRH, respectively. Results suggested that concentrations of serum T4 are higher 6 hours after the administration of TSH than after administration of TRH, using dosage regimens of 5 U of TSH/dog or 0.1 mg of TRH/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗