Identification of an enhancer that increases miR-200b~200a~429 gene expression in breast cancer cells

The miR-200b~200a~429 gene cluster is a key regulator of EMT and cancer metastasis, however the transcription-based mechanisms controlling its expression during this process are not well understood. We have analyzed the miR-200b~200a~429 locus for epigenetic modifications in breast epithelial and mesenchymal cell lines using chromatin immunoprecipitation assays and DNA methylation analysis. We discovered a novel enhancer located approximately 5.1kb upstream of the miR-200b~200a~429 transcriptional start site. This region was associated with the active enhancer chromatin signature comprising H3K4me1, H3K27ac, RNA polymerase II and CpG dinucleotide hypomethylation. Luciferase reporter assays revealed the upstream enhancer stimulated the transcription of the miR-200b~200a~429 minimal promoter region approximately 27-fold in breast epithelial cells. Furthermore, we found that a region of the enhancer was transcribed, producing a short, GC-rich, mainly nuclear, non-polyadenylated RNA transcript designated miR-200b eRNA. Over-expression of miR-200b eRNA had little effect on miR-200b~200a~429 promoter activity and its production did not correlate with miR-200b~200a~429 gene expression. While additional investigations of miR-200b eRNA function will be necessary, it is possible that miR-200b eRNA may be involved in the regulation of miR-200b~200a~429 gene expression and silencing. Taken together, these findings reveal the presence of a novel enhancer, which contributes to miR-200b~200a~429 transcriptional regulation in epithelial cells.

c-Rel controls multiple discrete steps in the thymic development of Foxp3+ CD4 regulatory T cells

The development of natural Foxp3⁺ CD4 regulatory T cells (nTregs) proceeds via two steps that involve the initial antigen dependent generation of CD25⁺GITR^hiFoxp3⁻CD4⁺ nTreg precursors followed by the cytokine induction of Foxp3. Using mutant mouse models that lack c-Rel, the critical NF-κB transcription factor required for nTreg differentiation, we establish that c-Rel regulates both of these developmental steps. c-Rel controls the generation of nTreg precursors via a haplo-insufficient mechanism, indicating that this step is highly sensitive to c-Rel levels. However, maintenance of c-Rel in an inactive state in nTreg precursors demonstrates that it is not required for a constitutive function in these cells. While the subsequent IL-2 induction of Foxp3 in nTreg precursors requires c-Rel, this developmental transition does not coincide with the nuclear expression of c-Rel. Collectively, our results support a model of nTreg differentiation in which c-Rel generates a permissive state for foxp3 transcription during the development of nTreg precursors that influences the subsequent IL-2 dependent induction of Foxp3 without a need for c-Rel reactivation.

'Ready-access' CT imaging for an orthopaedic trauma clinic

'Ready-Access' to CT imaging facilities in Orthopaedic Trauma Clinics is not a standard facility. This facility has been available at the regional trauma unit, in Merlin Park Hospital, Galway for the past four years. We reviewed the use of this facility over a 2-year period when 100 patients had CT scans as part of their trauma clinic assessment. The rate of CT scan per clinic was 0.6. The mean waiting time for a CT scan was 30 minutes. 20 (20%) new fractures were confirmed, 33 (33%) fractures were out-ruled, 25 (25%) fractures demonstrated additional information and 8 (8%) had additional fractures. 20 (20%) patients were discharged and 12 (12%) patients were admitted as a result of the CT scan. It adds little time and cost to CT scanning lists.

Non-union of the capitate with associated triangular fibrocartilage tear

We report a case of a 19-year-old boy who presented with a painful wrist 3 months after a fall. Plain radiographs demonstrated a non-union of a capitate fracture which was unrecognised at the time of injury. Magnetic resonance imaging confirmed the diagnosis and also demonstrated a tear of the triangular fibrocartilage complex. This combination of injuries has not been previously described.

K-wire position in tension band wiring of the olecranon - a comparison of two techniques

Tension band wiring is a recognised standard treatment for olecranon fractures. We studied the effect of K-wire position on backing out of the wire in a group of 80 patients with closed transverse olecranon fractures with a minimum follow-up time of 9 months. The rate of wires backing out as seen on X-ray was three times greater in patients who had K-wires passed down the long axis of the ulna rather than across the anterior cortex as recommended by the AO group. There was a corresponding higher rate of local complications in these patients. 42% of this group had to have the metal removed compared with 11.4% of the transcortical group. We compared the biomechanical properties of both K-wires positions in a human cadaveric model. The maximum pull-out strength for each configuration was recorded in 20 elbow joints. The average maximum pullout strength for the intramedullary wires was 56.3 N (range 27. 7-95.6 N) and 122.7 N for the transcortical wires (range 56.7-201.2). The results of both the clinical study and biomechanical data support the routine use of transcortical placement of K-wires in tension-band wiring of transverse olecranon fractures.

SPARING OF SENSATION TO PIN PRICK PREDICTS RECOVERY OF A MOTOR SEGMENT AFTER INJURY TO THE SPINAL CORD

We have reviewed 59 patients with injury to the spinal cord to assess the predictive value of the sparing of sensation to pin prick in determining motor recovery in segments which initially had MRC grade-0 power.

There were 35 tetraplegics (18 complete, 17 incomplete) and 24 paraplegics (19 complete, 5 incomplete), and the mean follow-up was 29.6 months. A total of 114 motor segments initially had grade-0 power but sparing of sensation to pin prick in the corresponding dermatome. Of these, 97 (85%) had return of functional power (≥ grade 3) at follow-up. There were 479 motor segments with grade-0 power but no sparing of sensation to pin prick and of these only six (1.3%) had return of functional power. Both of the above associations were statistically significant (chi-squared test, p < 0.0001).

After injury to the spinal cord, the preservation of sensation to pin prick in a motor segment with grade-0 power indicated an 85% chance of motor recovery to at least grade 3.

Sparing of sensation to pin prick predicts recovery of a motor segment after injury to the spinal cord

We have reviewed 59 patients with injury to the spinal cord to assess the predictive value of the sparing of sensation to pin prick in determining motor recovery in segments which initially had MRC grade-0 power. There were 35 tetraplegics (18 complete, 17 incomplete) and 24 paraplegics (19 complete, 5 incomplete), and the mean follow-up was 29.6 months. A total of 114 motor segments initially had grade-0 power but sparing of sensation to pin prick in the corresponding dermatome. Of these, 97 (85%) had return of functional power (> or = grade 3) at follow-up. There were 479 motor segments with grade-0 power but no sparing of sensation to pin prick and of these only six (1.3%) had return of functional power. Both of the above associations were statistically significant (chi-squared test, p < 0.0001). After injury to the spinal cord, the preservation of sensation to pin prick in a motor segment with grade-0 power indicated an 85% chance of motor recovery to at least grade 3.

An evaluation of the factors affecting neurological recovery following spinal cord injury

We reviewed 71 consecutive spinal cord injuries to determine the factors influencing neurological recovery. Sixty-three (35 tetraplegics and 28 paraplegics) were available for follow-up at a mean of 29.6 months. The American Spinal Injury Association (ASIA) scoring system was used on admission and at follow-up to determine change in neurological status. Treatment with corticosteroids or surgical intervention had no significant effect on outcome. Tetraplegics, both complete and incomplete, had a significantly better outcome than paraplegics (p < 0.02). Incomplete cord injury carried a better prognosis of motor recovery (p < 0.0001). Pattern of injury was an important determinant of recovery in the complete tetraplegia group. We conclude that many factors influence recovery following spinal cord injury and the effect of treatment may be difficult to demonstrate.

Timing of coronary artery bypass grafting after acute myocardial infarction

Appropriate timing for coronary artery bypass grafting (CABG) after acute myocardial infarction (AMI) remains controversial. We retrospectively examined 423 patients who underwent CABG within 21 days of an AMI between 1992 and 1995, mainly for postinfarction angina and complex anatomy. The operative mortality rates associated with increasing time intervals between AMI and CABG were 17.4, 9.1, 4.0, and 5.8 per cent, for less than 6 hours, 6 to 24 hours, 1 to 7 days, and 7 to 21 days, respectively. There were 25 (5.9%) deaths overall. Statistical analysis was performed to evaluate the following preoperative parameters: age, sex, reoperation, previous myocardial infarction (MI), MI type and location, anatomy, cardiogenic shock, unstable angina, ventricular arrhythmias, extending MI, ejection fraction, indications for surgery, cardiac index, and interval from infarction to CABG. Interval between operation and AMI did not have a significant impact on patient outcome. Factors associated with an increased hospital mortality were ejection fraction < 30 per cent, age > 70 years, presence of cardiogenic shock, and cardiac index < 1.5. Only cardiac index proved to be a significant predictor of mortality (P < 0.001). We conclude that the timing of CABG, in and of itself, has no significant effect on hospital mortality of symptomatic patients within 3 weeks of AMI.

'No more exercises'

Squadron Leader Shannon PMRAFNS discusses the preparation leading up to and including the days of the Iraqi conflict carried out by the Royal Air Force Hospital at Muharraq in the state of Bahrain.