Dogs are more permissive than cats or guinea pigs to experimental infection with a human isolate of Bartonella rochalimae

Bartonella rochalimae was first isolated from the blood of a human who traveled to Peru and was exposed to multiple insect bites. Foxes and dogs are likely natural reservoirs for this bacterium. We report the results of experimental inoculation of two dogs, five cats and six guinea pigs with the only human isolate of this new Bartonella species. Both dogs became bacteremic for 5–7 weeks, with a peak of 10³–10⁴ colony forming units (CFU)/mL blood. Three cats had low bacteremia levels (< 200 CFU/mL) of 6–8 weeks’ duration. One cat that remained seronegative had two bacterial colonies isolated at a single culture time point. A fifth cat never became bacteremic, but seroconverted. None of the guinea pigs became bacteremic, but five seroconverted. These results suggest that dogs could be a reservoir of this strain of B. rochalimae, in contrast to cats and guinea pigs.     

Food-purchasing patterns for home: a grocery store-intercept survey

OBJECTIVES: To identify the most common frequency of food-purchasing patterns and relate this pattern to characteristics of individuals and families.DESIGN: A customer-intercept survey was conducted in the greater Houston area, Texas, USA, in 2002. The frequency of food shopping at supermarkets, convenience stores and restaurants to buy food for eating at home was assessed.SUBJECTS: A total of 823 adults (78.5% female; mean age 37.4 years) who went to any of several grocery or convenience stores, including European, Hispanic and African Americans, and Asian/Pacific Islanders.RESULTS: Major food-shopping patterns were a weekly big trip with a few small trips (34.9%), biweekly big trips with a few small trips (21.9%), no big shopping trips (15.4%), a weekly big trip without small trips (13.9%), a monthly big trip (8.3%), and biweekly big trips without small trips (6.4%). While 61.1% of participants never went to convenience stores to buy fruit and vegetables (F&V) for eating at home, 67% went to restaurants for F&V. African American families shopped for food least frequently, while Asian American families shopped for food most frequently. Educational level was negatively associated with the use of convenience stores and positively associated with take-away from restaurants.CONCLUSIONS: There is substantial variability in the frequency of food shopping. Future research on food shopping should incorporate this variable.     

Production and characterization of recombinant equine prorelaxin

Relaxin is a peptide hormone produced by a wide variety of mammals. In the horse, the placenta is the major source of relaxin. Since pure equine relaxin is difficult to obtain to study its role in the pregnant mare, the objectives of this study were to produce recombinant equine prorelaxin and characterize its immunological and biological activity. First, an equine relaxin gene cassette was transfected into immortalized bovine mammary epithelial (MAC-T) cells. Second, immunological activity of media conditioned by transfected MAC-T cells was tested by Western blotting and quantified using a homologous equine radioimmunoassay. Finally, bioactivity of the conditioned media was tested using the human monocyte cell line, THP-1, which exhibits a rapid and dose-dependent increase in the accumulation of cAMP upon binding relaxin. The results showed that conditioned media, concentrated 5x, yielded 4.11 +/- 0.81 ng/ml recombinant equine prorelaxin. In addition, a 19 kDa immunoreactive band, corresponding to the expected size of equine prorelaxin, was visualized by SDS-PAGE. THP-1 cells incubated with conditioned media (5x) from transfected cells, in the presence of forskolin (1 microM) and isobutylmethylxanthine (50 microM), showed an increase in cAMP production over media from mock-transfected cells alone. In conclusion, recombinant equine prorelaxin secreted by MAC-T cells was both immunologically and biologically active. This study demonstrates the first attempt to produce recombinant equine prorelaxin, important for further study of the role of relaxin in the mare.     

A combination chemotherapy protocol with dose intensification and autologous bone marrow transplant (VELCAP-HDC) for canine lymphoma

Twenty-eight dogs with lymphoma were treated with a 12-week, 5-drug chemotherapy protocol concluding with high-dose cyclophosphamide supported by autologous bone marrow transplants. A dose escalation design was used to determine the maximum tolerated cyclophosphamide dose (MTD) in this setting. Three cyclophosphamide dose levels were given: 300 mg/ m2 IV (groupl, 3 dogs), 400 mg/m2 IV (group 2, 12 dogs), and 500 mg/m2 IV (group 3, 13 dogs); and the MTD was 500 mg/m2 IV. Toxicity was common but mild, and the dose-limiting toxicity was myelosuppression, specifically neutropenia. No dog died as a result of treatment-related toxicity. One dog in group 3 developed fever, neutropenia, and presumed sepsis and responded promptly to routine management. No other dog required hospitalization. Lower stage and higher cyclophosphamide dose (both increasing dose [study groups 1-3], and the highest dose [group 3]) compared with the lower doses combined (groups 1 and 2) were significantly associated with longer remission duration (all P < .0001). Median remission duration for dogs in group 3 was 54 weeks, compared with 21 weeks for dogs in groups 1 and 2 combined. Factors associated with longer survival time were lower stage (P = .042) and higher cyclophosphamide dose (both increasing dose [study groups 1-3], and the highest dose [group 3] compared with the lower doses combined [groups 1 and 2]) (P = .027). Median survival time for dogs in group 3 was 139 weeks, compared with 43 weeks and 68 weeks for dogs in groups 1 and 2, respectively.     

Comparative aspects and clinical outcomes of canine renal hemangiosarcoma

BACKGROUND: Hemangiosarcoma (HSA) is a common solid tumor of the spleen, heart, and skin of dogs. Renal HSA represents an uncommon anatomic variant, with little reported about its biologic behavior and clinical outcome. HYPOTHESIS: That renal HSA is associated with longer survival than other visceral forms of HSA. ANIMALS: 14 dogs with renal HSA. METHODS: Medical records from 1999 to 2004 were searched for dogs with histopathologically confirmed renal HSA, and data relevant to clinical signs, treatments, and outcomes were abstracted. RESULTS: Clinical signs were nonspecific, and the median duration of clinical signs before diagnosis was 60 days. Two dogs presented in cardiovascular collapse secondary to hemoperitoneum. Common hematologic and biochemical abnormalities were anemia (9/14), hematuria (7/14), and proteinuria (7/14). One dog had pulmonary metastasis at diagnosis. All dogs had evidence of a renal mass visualized by abdominal radiography (14/14), ultrasound (9/14), or both. All dogs underwent nephrectomy, and 4/14 dogs also received adjunctive chemotherapy. Median survival time of all dogs was 278 days (range 0-1,005 days), and dogs with hemoperitoneum had significantly shorter survival times than dogs without hemoperitoneum (62 days versus 286 days, P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: These results indicate that hemoperitoneum and distant metastasis at diagnosis appear to occur less frequently in dogs with renal HSA compared with other visceral forms of HSA. Furthermore, dogs with renal HSA have protracted disease progression, with improved 1-year survival rates and longer median survival time compared to dogs with splenic, cardiac, and retroperitoneal HSA.     

Phosphorus and nitrogen limitations to photosynthesis in Rocky Mountain bristlecone pine (Pinus aristata) in Colorado

We examined Pinus aristata Engelm. stands in four locations in Colorado: Almagre Mountain, Black Mountain, Goliath Peak and Quartzville. All stands are located at 3200-3700 m and face south-southeast. We measured maximum mass-based assimilation rates (A(max)) and nitrogen (N) and phosphorus (P) foliar concentrations on six foliar age classes, from which instantaneous photosynthetic N- and P-use efficiencies (PNUE and PPUE, respectively) and P:N ratios were estimated. Leaf mass per area (LMA) was also determined for each foliar age class from each site. Foliar age, P and N concentrations, and the P:N ratio explained the most variation in A(max) when data from all sites were combined. Leaf mass per area did not vary with foliar age class. Both P and N limit A(max), although P appears to be more limiting. The critical P:N ratio is approximately 0.12. Results for Black Mountain differed from the other sites, as A(max) was not correlated with age and was negatively correlated with LMA and P. Current findings showed no evidence of N saturation at the Front Range sites (Almagre Mountain and Goliath Peak); however, because P is a limiting nutrient, increased anthropogenic N availability at sites in the Front Range may cause adverse effects on photosynthesis, and perhaps growth, in the future.