Life-threatening bleeding from arterial-oesophageal fistula following oesophagectomy.

Oesophageal carcinoma remains one of the most common forms of cancer. Resection in the form of oesophagectomy and gastric interposition remains the standard surgical treatment and is associated with a high rate of post-operative morbidity. We report a case of a 71-year old male who underwent successful Ivor-Lewis oesophageal resection and developed life-threatening haemorrhage 2 weeks post-op, attributed to an arterial-oesophageal fistula. The patient was transferred to a specialist ENT centre with ligation of branches of the carotid artery, but intermittent bleeding continued. Following transfer to a specialist oesophago-gastric unit, repeated angiography was required to image the point of bleeding, which was embolised via percutaneous technique. The etiology, presentation, diagnosis and management of arterial-oesophageal fistulae are discussed, along with review of existing reports of similar complications and treatment options. A multidisciplinary approach, along with timely and often repeated imaging, is required in the management of arterial-oesophageal fistulae.

Colonization of Sitka spruce stumps by decay-causing hymenomycetes in paired inoculations.

Sitka spruce stumps were inoculated with decay fungi using colonized sawdust or dowel inoculum to investigate colonization in paired combinations. Estimates of domain sizes were made in the top 15cm of stump after 13-14 or 21-23 months with sawdust or dowel inoculations, respectively. None of the co-inoculated species prevented colonization by Heterobasidion annosum; sapwood colonization by Resinicium bicolor may limit growth of H. annosum colonies out of heartwood, reducing the incidence of disease transfer at root contacts. H. annosum colonized stumps despite the presence of competing inoculum. Reduced colonization occurred in paired inoculations with R. bicolor, but not with other fungi. Co-inoculations with Stereum sanguinolentum increased colonization by H. annosum. R. bicolor largely remained in the upper 3-4cm of stumps and reduced colonization by Melanotus proteus; growth of S. sanguinolentum was completely prevented. The results are discussed in relation to the colonization strategies of the decay fungi, their ability to colonize stumps in the presence of competitors and factors influencing development of communities of decay fungi in stumps.

Synthesis and characterization of a hemoglobin-ribavirin conjugate for targeted drug delivery.

A novel conjugate of human hemoglobin (Hb) and the nucleoside analogue ribavirin (RBV) was synthesized to demonstrate the utility of Hb as a biocompatible drug carrier for improved drug delivery in the treatment of liver disease. RBV is used in combination with interferon for the treatment of hepatitis C, but its side effects can result in dose limitation or discontinuation of treatment. Targeted delivery of RBV may help to prevent or minimize its toxicity. The hemoglobin-ribavirin conjugate (Hb-RBV) was designed to release bioactive drug upon endocytosis by cells and tissues involved in extracellular Hb catabolism and clearance. Ribavirin-5'-monophosphate (RBV-P) was prepared from RBV and activated as the 5'-monophosphorimidazolide (RBV-P-Im) for reaction with carbonmonoxyhemoglobin to yield Hb-RBV consisting of multiple RBV drugs covalently attached as physiologically labile phosphoramidates via their 5'-hydroxyl groups. A molar drug ratio of six to eight RBV molecules per Hb tetramer was obtained with near complete haptoglobin (Hp) binding of the drug modified Hb maintained. The conjugate complex (Hp-Hb-RBV) was selectively taken up in vitro by cells that express the hemoglobin-haptoglobin receptor, CD163. Recovered ribavirin enzymatically cleaved from Hb-RBV showed equipotent antiproliferative activity compared to control unconjugated RBV against human HepG2 and mouse AML12 liver cell lines. Based upon the reported high level of Hb uptake in the liver, Hb-RBV may be useful in the treatment of certain liver diseases, as well as inflammatory disorders associated with CD163-positive macrophages.

Expression of the hemoglobin-haptoglobin receptor CD163 on hematopoietic progenitors.

CD163, the hemoglobin-haptoglobin receptor, has been reported to be expressed exclusively on monocyte/ macrophages. Here we demonstrate that CD163 is also expressed by a subpopulation of hematopoietic stem/progenitor cells. Flow cytometric analysis shows that 1.9 +/- 1.3% (+/-SD, n = 16) of adult bone marrow and 2.0 +/- 1.8% (n = 8) of umbilical cord blood CD34(+) cells express cell-surface CD163, and 69.1 +/- 16.9% (n = 9) and 79.7 +/- 22.4% (n = 8) of the respective cells contain the CD163 protein intracellularly. The expression of CD163 by CD34(+) cells was confirmed by western blot analysis of cell lysates. Transcripts corresponding to the known predominant and variant 1 forms of CD163 were amplified via RT-PCR from CD34(+) cell-derived mRNA. A new variant (K11) with a deletion at the start of exon 15 was also detected. The deleted region contains a PKCalpha phosphorylation site and an amino acid sequence (YREM) that may support efficient receptor endocytosis. The addition of activating anti-CD163 antibodies increased the growth and differentiation of erythroid progenitors in colony-forming assays. These data suggest that hemoglobin may mediate a stimulatory effect on erythropoiesis through the activation of CD163 on hematopoietic progenitor cells.

Targeted delivery of ribavirin improves outcome of murine viral fulminant hepatitis via enhanced anti-viral activity.

Side effects of interferon-ribavirin combination therapy limit the sustained viral response achievable in hepatitis C virus (HCV) patients. Coupling ribavirin to macromolecular carriers that target the drug to the liver would reduce systemic complications. The aim of this study was to evaluate the efficacy of a hemoglobin-ribavirin conjugate (HRC 203) in murine hepatitis virus strain 3 (MHV-3) induced viral hepatitis. HRC 203 had greater anti-viral activity on both isolated hepatocytes and macrophages, whereas both ribavirin and HRC 203 inhibited production of the pro-inflammatory cytokines interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) by macrophages. In vivo, untreated MHV-3-infected mice all developed clinical and biochemical signs of acute viral hepatitis and died by day 4 post infection. Livers recovered from untreated infected mice showed greater than 90% necrosis. In contrast, survival was enhanced in both ribavirin- and HRC 203-treated mice with a marked reduction in biochemical [ALT(max) 964 +/- 128 IU/L (ribavirin); 848 +/- 212 IU/L (HRC 203)] and histological evidence of hepatic necrosis (<10% in ribavirin/HRC 203 vs. 90% in untreated controls). Clinically, HRC 203-treated mice behaved normally, in contrast to ribavirin-treated mice, which developed lethargy and abnormal fur texture. In conclusion, targeted delivery of ribavirin to the liver alters the course of MHV-3 infection as demonstrated by prolonged survival, improved behavior, and reduced signs of histologically evident disease, as well as inhibition of viral replication and production of inflammatory cytokines in vitro.