Urologic Oncology.

Primary renal tumors are an uncommon diagnosis in small animals. Presentation, treatment, and prognosis depend on tumor type. Surgery with or without chemotherapy are the mainstays of treatment. Transitional cell carcinoma is the most common tumor of the urinary system. Clinical signs include hematuria, stranguria, and pollakiuria. Metastatic disease can develop over time within medial iliac lymph nodes, lungs, and vertebrae. Treatment of transitional cell carcinoma centers on chemotherapy with mitoxantrone, vinblastine, or carboplatin. Other agents used with success, include toceranib phosphate and chlorambucil. Interventional surgery, such as stenting and laser ablation, is used in a palliative setting addressing urinary obstruction.

Mutational analysis of betaCOP (Sec26p) identifies an appendage domain critical for function.

BACKGROUND: The appendage domain of the gammaCOP subunit of the COPI vesicle coat bears a striking structural resemblance to adaptin-family appendages despite limited primary sequence homology. Both the gammaCOP appendage domain and an equivalent region on betaCOP contain the FxxxW motif; the conservation of this motif suggested the existence of a functional appendage domain in betaCOP. RESULTS: Sequence comparisons in combination with structural prediction tools show that the fold of the COOH-terminus of Sec26p is strongly predicted to closely mimic that of adaptin-family appendages. Deletion of the appendage domain of Sec26p results in inviability in yeast, over-expression of the deletion construct is dominant negative and mutagenesis of this region identifies residues critical for function. The ArfGAP Glo3p was identified via suppression screening as a potential downstream modulator of Sec26p in a manner that is independent of the GAP activity of Glo3p but requires the presence of the COOH-terminal ISS motifs. CONCLUSION: Together, these results indicate an essential function for the predicted betaCOP appendage and suggest that both COPI appendages perform a biologically active regulatory role with a structure related to adaptin-family appendage domains.

Genetic analysis of yeast Yip1p function reveals a requirement for Golgi-localized rab proteins and rab-Guanine nucleotide dissociation inhibitor.

Yip1p is the first identified Rab-interacting membrane protein and the founder member of the YIP1 family, with both orthologs and paralogs found in all eukaryotic genomes. The exact role of Yip1p is unclear; YIP1 is an essential gene and defective alleles severely disrupt membrane transport and inhibit ER vesicle budding. Yip1p has the ability to physically interact with Rab proteins and the nature of this interaction has led to suggestions that Yip1p may function in the process by which Rab proteins translocate between cytosol and membranes. In this study we have investigated the physiological requirements for Yip1p action. Yip1p function requires Rab-GDI and Rab proteins, and several mutations that abrogate Yip1p function lack Rab-interacting capability. We have previously shown that Yip1p in detergent extracts has the capability to physically interact with Rab proteins in a promiscuous manner; however, a genetic analysis that covers every yeast Rab reveals that the Rab requirement in vivo is exclusively confined to a subset of Rab proteins that are localized to the Golgi apparatus.

Cisplatin and doxorubicin toxicosis in dogs with osteosarcoma.

Toxicosis associated with doxorubicin and cisplatin administration starting either 2 or 10 days after limb amputation for osteosarcoma was examined retrospectively in dogs. The purpose was to determine whether dosage and timing of chemotherapy affected rates of toxicosis after administration of the 1st treatment. Records of 100 dogs with appendicular osteosarcoma without evidence of metastases or concurrent disease were examined. Dogs received chemotherapy with doxorubicin and cisplatin every 3 weeks for 3 treatments starting 2 days (n = 51) or 10 days (n = 49) after amputation. The dosage of cisplatin was 60 mg/m2 and was given with 6-hour saline diuresis and butorphanol. Doxorubicin was given at 12.5-25 mg/ml during fluid administration. Hematologic data were collected before and weekly after treatment. Client interviews were conducted to assess gastrointestinal toxicosis during the interval between treatments. The reported toxicoses were graded on a scale of 0 to 4. Dogs receiving 25 mg/m2 of doxorubicin experienced greater rates of grade 4 toxicity (67%; n = 6) than dogs in groups receiving 12.5-20 mg/m2 of doxorubicin (< or = 25%; n = 94, P = .03). Dogs in the Day 2 group experienced greater rates (35%) of grade 4 toxicity than dogs in the Day 10 group (12%, P = .007). We concluded that chemotherapy administered 2 days after surgery produced an unacceptable level of toxicoses. except at greatly reduced dosages, and that even with a delay of treatment, 25 mg/m2 of doxorubicin, when given in combination with cisplatin at 60 mg/m2, was too toxic for routine use.