Carcinoma of the apocrine glands of the anal sac in dogs: 113 cases (1985-1995)

OBJECTIVE: To characterize the signalment, clinical signs, biological behavior, and response to treatment of carcinoma of the apocrine glands of the anal sac in dogs. DESIGN: Retrospective study. ANIMALS: 113 dogs with histologically confirmed carcinoma of the apocrine glands of the anal sac. PROCEDURE: Data on signalment, clinical signs, and staging were reviewed and analyzed along with treatment modality for potential association with survival time. RESULTS: Sex distribution was approximately equal (54% female, 46% male). One hundred four dogs underwent treatment consisting of surgery, radiation therapy, chemotherapy, or multimodal treatment. Median survival for treated dogs was 544 days (range, 0 to 1,873 days). Dogs treated with chemotherapy alone had significantly shorter survival (median, 212 days) than those receiving other treatments (median, 584 days). Dogs not treated with surgery had significantly shorter survival (median, 402 days) than those that underwent surgery as part of their treatment (median, 548 days). Dogs with tumors > or = 10 cm2 had significantly shorter survival (median, 292 days) than dogs with tumors < 10 cm2 (median, 584 days). Hypercalcemia was identified in 27% (n = 29) of dogs, and those dogs had significantly shorter survival (median, 256 days), compared with those that were normocalcemic (median, 584 days). Dogs with pulmonary metastasis had significantly shorter survival (median, 219 days) than dogs without evidence of pulmonary metastasis (median, 548 days). CONCLUSIONS AND CLINICAL RELEVANCE: Unlike most previous reports, this study revealed an approximately equal sex distribution, and results suggest a more favorable prognosis.     

Changes in soil N status and N supply rates in agricultural land afforested with eucalypts in south-western Australia

In south-western Australia, plantations of Eucalyptus globulus are being established on land that has previously been used for conventional agriculture. Sustaining the productivity of these tree plantations in second and subsequent rotations will depend partly on maintenance of soil fertility, especially soil nitrogen (N) supply rates. We compared soil N status and supply rates between adjacent pasture and 6-11 year old first-rotation eucalypt plantations at 31 paired sites in south-western Australia. Total soil N varied widely among sites (0.07-0.68% in the fraction <2 mm of the 0-10 cm soil layer), but concentrations averaged over all sites did not differ between land-use types. However, measurements of the indices of mineralization (mineral N produced during incubation of intact cores), potentially available N (from short-term anaerobic incubation) and model-predicted mineralization rates during 28-day aerobic incubations were generally lower in afforested soils than in pasture soils. This finding was supported by in situ field estimates of N mineralization over a full year at two contrasting paired pasture-plantation sites. At each site there was a marked reduction (2-3-fold) in net annual mineral N flux rates in soils under eucalypt plantations. Reduced N mineralization associated with tree plantations was due to both changes in soil organic matter quality and the generally lower soil moisture content under trees in comparison with pasture. These results suggest that N supply rates of pasture soils are likely to decline when the land is planted to successive crops of eucalypts. Eucalypt plantation managers will need to take account of this and implement management strategies to maintain adequate N nutrition to sustain tree growth in future rotations.     

Legume cover cropping effects on early growth and soil nitrogen supply in eucalypt plantations in south-western India

Growth and soil N supply in young Eucalyptus tereticornis stands at two sites in Kerala, India, were examined in response to cover cropping with three legume species (Pueraria phaseoloides, Stylosanthes hamata, and Mucuna bracteata). The effects of legume residues on soil N supply were investigated in a long-term (392 day) laboratory incubation using leaching micro-lysimeters. Residues from the eucalypt and legume species had different rates of net N release during the laboratory incubation. Net N release was significantly related to residue N concentration (R² =0.94), the C:N ratio (R² =0.91), the lignin:N ratio (R² =0.83), and the (lignin + soluble polyphenol):N ratio (R² =0.95). Nitrogen release rates declined in the order Mucuna > Pueraria > Eucalyptus > Stylosanthes. There was no net N release from Stylosanthes residues during the 392-day laboratory incubation, whereas Mucuna and Pueraria released N throughout the incubation period. Net N release from mixtures of legume and eucalypt residues was not additive in the early phase of the incubation, probably because eucalypt residues initially immobilized a portion of the legume-derived N in addition to the soil-derived N. Legume establishment had no significant effect on tree growth at one site (Kayampoovam), but resulted in depressed tree growth at the lower rainfall site (Punnala) at 18 months. There were no significant treatment effects on growth at Punnala after that time. Cover cropping with legumes during the early phase of forest plantation growth may be a useful mechanism to enhance soil N supply and optimize the synchrony between N supply and tree N uptake. Although these effects did not translate into improved plantation growth in the 3 years of this study, improved soil organic matter and N fertility may help ensure sustainable productivity over several rotations in the future. This study showed that the effect of legumes on N dynamics varies markedly with legume species. This, together with other factors (e.g. competition with trees, N fixation capacity), will be important in selecting suitable species for cover cropping in forest plantations.     

Single agent gemcitabine chemotherapy in dogs with spontaneously occurring lymphoma

BACKGROUND: Gemcitabine has been shown to be effective as a single agent in a variety of tumors including nonHodgkin's lymphoma. Its use in veterinary medicine has been limited and to date this drug has not been used as a first-line therapy in dogs with lymphoma. HYPOTHESIS: Gemcitabine as a single agent may be efficacious in dogs presented for the first time with lymphoma. ANIMALS: Twenty-four dogs with spontaneously occurring lymphoma. METHODS: All dogs were clinically staged and given gemcitabine at 400 mg/m(2) over a 30-minute intravenous infusion weekly for 3 weeks and then given 1 week off treatment before starting a second cycle. RESULTS: A single dose of gemcitabine lowered both neutrophil count (decrease in mean neutrophil count from 10,640 cells/ microL to 3,140 cells/microL) and platelet count (decrease in mean platelet count from 201,290 cells/microL to 139,190 cells/microL) 7 days after administration. Consequently gemcitabine dosage was reduced at the second treatment in 8 of 21 dogs or a dose delay of 1-7 days and a reduction of dosage was used in 7 of 21 dogs. Seven dogs completed the assigned 4-week cycle. Two of these dogs had progressive disease and 5 had stable disease. No objective responses were seen in dogs treated with a second cycle of gemcitabine. CONCLUSIONS AND CLINICAL IMPORTANCE: Gemcitabine administration as a single agent resulted in hematologic toxicity and did not reduce lymphoma burden. If gemcitabine is to be used in veterinary medicine, additional prospective pharmacologic studies should be done to determine the appropriate dosage, regimen, and schedule of use before it can be recommended for use in the treatment of dogs with lymphoma as a single agent.     

Esophagitis and esophageal strictures.

Esophagitis and esophageal strictures are important causes of esophageal disease in dogs and cats. Clinical suspicion is created when the clinician recognizes the clinical signs suggestive of esophageal disease and accounts for historical information and physical examination findings. Once suspected, the diagnosis of esophagitis and esophageal strictures is a fairly simple one in most cases. Although the benefit of diminishing secretion of gastric acid in patients with esophagitis is unquestioned, other questions regarding adjunctive medical treatments, such as sucralfate and glucocorticoids for dogs and cats with esophagitis, have not been answered through appropriate clinical studies. Esophageal strictures are readily treated with balloon dilation or esophageal bougienage, and clients can expect most patients to become functional, although dietary change may be necessary.     

Fecal polymerase chain reaction with 16S ribosomal RNA primers can detect the presence of gastrointestinal Helicobacter in dogs

Questions about pathogenesis and therapy for Helicobacter infections in dogs could be answered with a simple, noninvasive, sensitive, and specific diagnostic test. We hypothesized that a fecal polymerase chain reaction (PCR) assay would detect Helicobacter and could be useful for assessing therapeutic responses. Paired gastric biopsies and fecal samples were obtained from 39 random source dogs (group 1). Gastric biopsies from each of these dogs had histologic evidence of gastric spiral bacteria, and paired gastric tissue and fecal samples produced a 375-base pair (bp) product when amplified by PCR with Helicobacter-specific primers. Specificity of the PCR product was confirmed by detection of expected 60-, 119-, and 196-bp products following Hinfl digestion. Direct sequencing of amplicons from paired PCR products from gastric biopsy and fecal samples from 8 group I dogs showed that gastric products had the highest homologies with known gastric Helicobacter species, whereas fecal products had the highest homologies with intestinal species. Healthy mixed-breed dogs (group II; n = 8) with histologically confirmed spiral bacteria infection were treated with a 21-day course of metronidazole, amoxicillin, and famotidine. Fecal samples were collected from group II dogs twice before and within 3 days of completion of treatment. The PCR results correctly identified 15/16 pretreatment samples as positive: 1 pretreatment sample was negative. PCR results identified 8/8 posttreatment samples as Helicobacter negative. Fecal PCR is a useful test for detecting Helicobacter infection in dogs. This assay may be useful as a screening test for infection and could be used to address questions relevant to pathogenesis and therapy.