Percutaneous radiofrequency ablation of renal tumours: Case series of 11 tumours and review of published work

Detection of renal cell carcinoma (RCC) is increasing with the greater use of cross‐sectional imaging and up to two‐thirds of RCCs are discovered incidentally in asymptomatic patients. The traditional option of nephrectomy or partial nephrectomy may not always be appropriate. A minimally invasive treatment alternative is radiofrequency ablation (RFA). We retrospectively reviewed the RFA cases for renal tumours at our institution between January 2004 and June 2006. Thirteen RFA treatment sessions were conducted for 11 neoplasms in 11 patients. Mean patient age was 74.4 years (61–88 years). Imaging was carried out after ablation with a mean follow up of 8.0 months (2–26 months). No residual tumour was observed after the first RFA treatment in 82% of patients (nine of 11). Two patients required a second RFA treatment for residual (one) or recurrent tumour (one). RFA is emerging as a useful technique for treatment of small renal tumour. A number of short‐term studies reflect this, however, long‐term findings are still lacking.     

Domain organization and flavin adenine dinucleotide-binding determinants in the aerotaxis signal transducer Aer of Escherichia coli

Aerotactic responses in Escherichia coli are mediated by the membrane transducer Aer, a recently identified member of the superfamily of PAS domain proteins, which includes sensors of light, oxygen, and redox state. Initial studies of Aer suggested that it might use a flavin adenine dinucleotide (FAD) prosthetic group to monitor cellular redox changes. To test this idea, we purified lauryl maltoside-solubilized Aer protein by His-tag affinity chromatography and showed by high performance liquid chromatography, mass spectrometry, and absorbance spectroscopy that it bound FAD noncovalently. Polypeptide fragments spanning the N-terminal 290 residues of Aer, which contains the PAS motif, were able to bind FAD. Fusion of this portion of Aer to the flagellar signaling domain of Tsr, the serine chemoreceptor, yielded a functional aerotaxis transducer, demonstrating that the FAD-binding portion of Aer is sufficient for aerosensing. Aerotaxis-defective missense mutants identified two regions, in addition to the PAS domain, that play roles in FAD binding. Those regions flank a central hydrophobic segment needed to anchor Aer to the cytoplasmic membrane. They might contact the FAD ligand directly or stabilize the FAD-binding pocket. However, their lack of sequence conservation in Aer homologs of other bacteria suggests that they play less direct roles in FAD binding. One or both regions probably also play important roles in transmitting stimulus-induced conformational changes to the C-terminal flagellar signaling domain to trigger aerotactic behavioral responses.     

THE AUSTRALIAN & NEW ZEALAND JOURNAL OF OBSTETRICS & GYNAECOLOGY

During the years 1971-1984 urinary oestriol excretion was tested in 51,427 patients (group 1). One or more low oestriol value was found in 10.7% of patients; in this group the stillbirth rate was 6.8 times higher, the neonatal death rate 3.8 times higher, and fetal growth retardation rate 3.5 times higher than in patients with normal oestriol values (all p less than 0.00001). During the years 1985-1989 a further 20,635 patients were tested (group 2) and 7.6% had one or more low oestriol value. The perinatal mortality rate in patients with normal oestriol excretion fell from 0.8% in group 1 to 0.5% in group 2 (p less than 0.005), and in patients with low oestriol excretion from 4.2% in group 1 to 2.4% in group 2 (p less than 0.002). However, patients in group 2 with low oestriol values still had significantly unfavourable results, compared to those with normal oestriol values--stillbirth rate 3.3 times higher, neonatal death rate 4.6 times higher, and fetal growth retardation rate 3.2 times higher (all p less than 0.00001). Intravenous dextrose and aminoacid infusions were given to 967 patients who had persistently low oestriol values in spite of rest in hospital, in an attempt to correct fetoplacental function; the perinatal mortality rate was 0.9% in the 660 (68.3%) who responded favourably, and 9.8% in the 307 (31.7%) who did not respond (p less than 0.0001).     

Immunity to hepatitis B, poliomyelitis and measles in fully vaccinated Aboriginal and Torres Strait Island children

Objective: To determine the immunity to hepatitis B, poliomyelitis and measles in fully vaccinated Aboriginal and Torres Strait Island children in north Queensland.
Methodology: A cross-sectional survey of immunity in a sample of children; 101 fully vaccinated Aboriginal and Torres Strait Island children, with a median age of 24.5 months, from 10 communities in North Queensland participated in this study. The main outcome measures were the prevalence of adequate antibody levels against hepatitis B, poliomyelitis and measles.
Results: Only 54% (95% Cl 44–63%) of the children had adequate immunity (10 m iu/mL) to hepatitis B, and one child had been infected despite vaccination. Although all the children (95% Cl 96–100%) had adequate immunity (i.e. neutralizing antibodies at a dilution of 1:8) to poliovirus 2, only 93% (95% Cl 86–96%) and 60% (95% Cl 50–69%) had adequate immunity to polioviruses 1 and 3, respectively. Nearly all (96%; 95% Cl 90–98%) of the children had adequate immunity (i.e. detectable IgG antibody) to measles.
Conclusions: Although a relatively low proportion of the children had adequate antibody levels against hepatitis B the clinical significance of this observation is uncertain. Further studies are needed to determine whether fully vaccinated Torres Strait Island children have been adequately protected and whether they require a booster dose of hepatitis B vaccine. A substantial proportion of fully vaccinated Aboriginal and Torres Strait Island children are inadequately protected against poliomyelitis, and therefore any such child with acute flaccid paralysis should be investigated fully for poliomyelitis. Vaccinated Aboriginal and Torres Strait Island children are well protected against measles, as are other Australian children.     

Telomere maintenance as a target for anticancer drug discovery

Maintenance of telomeres--specialized complexes that protect the ends of chromosomes--is undertaken by the enzyme complex telomerase, which is a key factor that is activated in more than 80% of cancer cells that have been examined so far, but is absent in most normal cells. So, targeting telomere-maintenance mechanisms could potentially half tumour growth across a broad spectrum of tumour types, with little cytotoxic effect outside tumours. Here, we describe the current understanding of telomere biology, and the application of this knowledge to the development of anticancer drugs.     

Effects of transient loss of shear stress on blood-brain barrier endothelium: role of nitric oxide and IL-6

Loss of blood-brain barrier (BBB) function may contribute to post-ischemic cerebral injury by yet unknown mechanisms. Ischemia is associated with anoxia, aglycemia and loss of flow (i.e. shearing forces). We tested the hypothesis that loss of shear stress alone does not acutely affect BBB function due to a protective cascade of mechanisms involving cytokines and nitric oxide (NO). To determine the relative contribution of shear stress on BBB integrity we used a dynamic in vitro BBB model based on co-culture of rat brain microvascular endothelial cells (RBMEC) and astrocytes. Trans-endothelial electrical resistance (TEER), IL-6 release and NO levels were measured from the lumenal and ablumenal compartments throughout the experiment. Flow-exposed RBMEC were challenged with 1 h of normoxic-normoglycemic flow cessation (NNFC) followed by reperfusion for 2 to 24 h. NNFC caused a progressive drop in nitric oxide production during flow cessation followed by a time-dependent increase in ablumenal IL-6 associated with a prolonged NO increase during reperfusion. The nitric oxide synthetase (NOS) inhibitor L-NAME (10 microM) abrogated all effects of NNFC, including changes in NO and cytokine production. BBB permeability did not increase during or after NNFC/reperfusion, but was increased by treatment with L-NAME or when the effects of IL-6 were blocked. Flow adapted RBMEC and astrocytes respond to NNFC/reperfusion by overproduction of IL-6, possibly secondary to increased production of NO during the reperfusion. Maintenance of BBB function during and following NNFC appears to depend on intact NO signaling and IL-6 release.