Primary Amyloidosis With Renal Involvement: Outcomes in 77 Consecutive Patients at a Single Center.

BACKGROUND: Outcomes in primary amyloid renal patients are of interest as the era of monoclonal antibody therapies begins. PATIENTS AND METHODS: We studied 77 consecutive primary amyloid renal patients (58% men) for renal progression (end stage renal disease [ESRD]), renal response (RR), and overall survival (OS). RESULTS: At diagnosis median age was 63 (range, 35-81) years, estimated glomerular filtration rate 70 mL/min (range, 5-114), difference between involved and uninvolved free light chains 127 mg/L (range, 1-9957), ESRD 4%, renal stage 2 and 3 78%, and cardiac stage 2 and 3 56%. Ninety-six percent received bortezomib and 44% stem cell transplantation as well as bortezomib, 68% achieved complete or very good partial hematologic response (CR/VGPR), 34% had ESRD, and 39% RR. Median times to ESRD and RR were 18 (range, 3-81) and 12 (range, 2-30) months, respectively. Median OS was not reached in this cohort and was not reached from onset of ESRD. More than two-thirds of patients with ESRD also achieved CR/VGPR. In those without ESRD at diagnosis, baseline creatinine and absent RR predicted progression to ESRD in multivariate Cox regression analysis, whereas CR/VGPR predicted RR. In multivariate Cox regression analysis, cardiac stage and achievement of CR/VGPR predicted OS, enabling construction of a prognostic model. CONCLUSION: Anti-plasma cell therapies provide a definite albeit limited benefit and new approaches to amyloid-related organ dysfunction are needed.

Carcinoid syndrome from small bowel endocrine carcinoma in the absence of hepatic metastasis.

An 80-year-old male patient presented with abdominal pain, paroxysmal diaphoresis, diarrhoea and vomiting. CT scan revealed a small bowel endocrine carcinoma (or 'carcinoid' tumour), but the absence of hepatic disease. The lesion was excised 'en-bloc'. Intra-operatively, there was wide fluctuation in blood pressure associated with tumour manipulation, with hyper- and hypotension. Carcinoid syndrome usually occurs from gastrointestinal tumours when hepatic metastases occur, causing flushing, diarrhoea, bronchoconstriction and murmurs from cardiac valvular lesions. This patient did not have radiological evidence of hepatic metastasis, but the syndrome could still occur with midgut tumours via local invasion of the retroperitoneal circulation, or by action of substances other than serotonin that do not undergo hepatic metabolism.

Marine-derived metabolites of S-adenosylmethionine as templates for new anti-infectives.

S-Adenosylmethionine (AdoMet) is a key biochemical co-factor whose proximate metabolites include methylated macromolecules (e.g., nucleic acids, proteins, phospholipids), methylated small molecules (e.g., sterols, biogenic amines), polyamines (e.g., spermidine, spermine), ethylene, and N-acyl-homoserine lactones. Marine organisms produce numerous AdoMet metabolites whose novel structures can be regarded as lead compounds for anti-infective drug design.

Microwave synthesis and evaluation of phenacylhomoserine lactones as anticancer compounds that minimally activate quorum sensing pathways in Pseudomonas aeruginosa.

The bacterial quorum sensing (QS) signal molecule 3-oxo-dodecanoyl-L-homoserine lactone (OdDHL) is produced by the opportunistic pathogen Pseudomonas aeruginosa and controls expression of virulence factors associated with life threatening infections in immune compromised individuals. OdDHL has also demonstrated anticancer activity, yet its ability to enhance pathogenicity of P. aeruginosa compromises further consideration as a potential anticancer agent. In search of acylhomoserine lactones that selectively inhibit cancer cell growth, a library of phenacylhomoserine lactone analogues has been prepared by microwave synthesis and evaluated for cancer growth inhibition and quorum sensing activation. Comparative SAR analysis demonstrates that both anticancer and QS signaling systems require long acyl side chains with a 3-oxo substitution for maximum activity. Compound 12b, 3-oxo-12-phenyldodecanoyl-L-homoserine lactone, was identified as a lead compound with strong cancer growth inhibitory activity that minimizes activation of QS signaling pathways in a P. aeruginosa reporter assay.

A new class of homoserine lactone quorum-sensing signals.

Quorum sensing is a term used to describe cell-to-cell communication that allows cell-density-dependent gene expression. Many bacteria use acyl-homoserine lactone (acyl-HSL) synthases to generate fatty acyl-HSL quorum-sensing signals, which function with signal receptors to control expression of specific genes. The fatty acyl group is derived from fatty acid biosynthesis and provides signal specificity, but the variety of signals is limited. Here we show that the photosynthetic bacterium Rhodopseudomonas palustris uses an acyl-HSL synthase to produce p-coumaroyl-HSL by using environmental p-coumaric acid rather than fatty acids from cellular pools. The bacterium has a signal receptor with homology to fatty acyl-HSL receptors that responds to p-coumaroyl-HSL to regulate global gene expression. We also found that p-coumaroyl-HSL is made by other bacteria including Bradyrhizobium sp. and Silicibacter pomeroyi. This discovery extends the range of possibilities for acyl-HSL quorum sensing and raises fundamental questions about quorum sensing within the context of environmental signalling.