Atrial myocarditis as a cause of sinus arrest in a dog

A 10-year-old male cairn terrier cross was presented with a history of myxomatous mitral valve disease diagnosed six months previously and with a four-week history of intermittent collapse. On 24 hour electrocardiograph (Holter) analysis, periods of no discernable electrical cardiac activity, which coincided with three collapsing episodes, were identified. Unfortunately, on re-presentation for removal of the Holter monitor, the dog collapsed and died. A post-mortem examination was conducted, and histology of the right and left atrium showed evidence of myocarditis. This is the first reported case, to our knowledge, of collapse because of electrical asystole in a dog with atrial myocarditis.

Low-dose lenograstim is as effective as standard dose in shortening neutrophil engraftment time following myeloablative chemotherapy and peripheral blood progenitor cell rescue

Granulocyte colony-stimulating factor (G-CSF) is widely used following myeloablative chemotherapy (high-dose therapy; HDT) and peripheral blood progenitor cell rescue (PBPCR) to reduce neutrophil engraftment time. The dose and duration required to gain maximum clinical and economic benefit has not been fully investigated. This double blind placebo-controlled randomised trial was performed to determine whether short course low-dose or standard-dose Lenograstim (L) would influence recovery of haematopoiesis following HDT and PBPCR. Sixty-one patients were randomised between May 1999 and November 2004, to receive standard-dose lenograstim (263 microg/d), low-dose lenograstim (105 microg/d) or placebo injections. These commenced on day +5 following PBPCR and continued until neutrophil engraftment [absolute neutrophil count (ANC)] > or = 0.5 x 10(9)/l. Patients received standard supportive care until haemopoietic recovery. Both standard- and low-dose lenograstim resulted in a significantly shorter median time to neutrophil recovery (ANC > or = 0.1 x 10(9)/l:10.0 vs. 11.0 d, P = 0.025; ANC > or = 0.5 x 10(9)/l:11.0 vs. 14.0 d, P = 0.0002) compared with placebo. There was no significant difference in blood product support, antibiotic usage, documented infection, overall survival or relapse-free survival between the groups. Short course low-dose lenograstim is as effective as standard-dose in reducing neutrophil engraftment time following HDT and PBPCR.

Randomised, placebo-controlled, trial comparing low dose versus standard dose Lenograstim (L) following myeloablative chemotherapy (HDT) and peripheral blood progenitor cell rescue (PBPCR) for lymphoma

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Background: This trial was performed to determine whether low-dose or standard dose L would influence recovery of haematopoiesis following HDT and PBPCR. Methods: 61 patients (pts) with non-Hodgkin lymphoma (40) or Hodgkin’s disease (21) undergoing HDT were randomised. Pts had normal peripheral blood counts prior to HDT (Hb ≥100g/L, total white cell count ≥ 3.0, neutrophils (N) ≥ 1.0 and platelets ≥ 50, and had a minimum 2.5 million CD34+ cells/kg PBPC previously collected following mobilisation with Cyclophosphamide 3g/m2 and G-CSF. All received HDT with BCNU 300mg/m2 d-7, Etoposide 200mg/m2 od d-5-d-2, Cytosine arabinoside 200mg/m2 bd d-5-d-2 and Melphalan 140mg/m2 d-1 before return of PBPC on D0. Pts were allocated standard dose L 263mcg daily (20 pts), low dose L 105mcg daily (21 pts) or placebo injections (20 pts). These commenced on day +5 following PBPCR and continued until N≥0.5. Pts received standard supportive care including prophylactic Fluconazole and Acyclovir, but not routine antibacterial prophylaxis, until haemopoietic recovery. Results: L at any dose resulted in a significantly shorter median time to N recovery ≥0.1 (10.0 vs 11.0 days, P=0.02) and ≥0.5 (11.0 vs 14.0 days, p=0.0003) compared to placebo. The only significant difference between standard- and low-dose L was in hospital stay (21.0 vs 22.0 days, p=0.04), however L at any dose showed a significant reduction over placebo (22.0 vs 23.0 days, p=0.01). Conclusions: Short course low dose L is as effective as standard dose in reducing neutrophil engraftment time following HDT and PBSCR. L at any dose reduces hospital stay when compared to placebo. This approach should be considered for those patients in whom growth factor support is indicated. Long-term follow-up data will be presented.

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No significant financial relationships to disclose.

Anti-tumour activity in non-small cell lung cancer models and toxicity profiles for novel ruthenium(II) based organo-metallic compounds

Novel ruthenium(II) organo-metallic compounds are active in ovarian cancer models [Aird RE, Cummings J, Ritchie AA, Muir M, Morris RE, Chen H, et al. In vitro and in vivo activity and cross resistance profiles of novel ruthenium(II) organometallic arene complexes in human ovarian cancer. Br J Cancer 2002;86(10):1652-7]. [(eta6-C6H5C6H5)Ru(en)Cl]+ (as a PF6 salt, where en=ethylenediamine (RM175)) has been evaluated in a 13-cell line panel. Particular sensitivity (approximately 10-fold lower than mean IC50) was noted in breast cancer and non-small cell lung cancer cell lines. In addition, IC50 in the A549 was 2 microM and RM175 (25 mg kg-1, days 1 and 5, i.p.) caused a significant (p=0.004) growth delay in a xenograft model. HC11 [(eta6-tetrahydroanthracene)Ru(en)Cl]PF6 was more potent in the A549 cell line (IC50 0.5 microM). HC11 (25 mg kg-1, days 1, 8 and 15, i.p.) was also active in vivo. Following RM175 25 mg kg-1, days 1 and 5, and 15 mg kg-1, days 1-5, HC11 25 and 40 mg kg-1, day 1, elevated alanine transaminase levels were detected, suggesting hepatotoxicity. No changes were observed in kidney or haematological parameters. In liver sections, multi-focal hepatic necrosis was seen, becoming confluent at high doses of HC11. In vitro studies confirmed that HC11 was more toxic than RM175 to fresh human hepatocytes and equitoxic to mithramycin. Liver toxicity may be related to the arene ligand and modification may reduce the potential for hepatic toxicity, while maintaining the anti-tumour activity seen.