CSF bilirubin-spectrophotometry or direct measurement?

Deficiency of Endothelium-Specific Transcription Factor Sox17 Induces Intracranial Aneurysm

Background—

Intracranial aneurysm (IA) is a common vascular disorder that frequently leads to fatal vascular rupture. Although various acquired risk factors associated with IA have been identified, the hereditary basis of IA remains poorly understood. As a result, genetically modified animals accurately modeling IA and related pathogenesis have been lacking, and subsequent drug development has been delayed.

Methods and Results—

The transcription factor Sox17 is robustly expressed in endothelial cells of normal intracerebral arteries. The combination of Sox17 deficiency and angiotensin II infusion in mice induces vascular abnormalities closely resembling the cardinal features of IA such as luminal dilation, wall thinning, tortuosity, and subarachnoid hemorrhages. This combination impairs junctional assembly, cell-matrix adhesion, regeneration capacity, and paracrine secretion in endothelial cells of intracerebral arteries, highlighting key endothelial dysfunctions that lead to IA pathogenesis. Moreover, human IA samples showed reduced Sox17 expression and impaired endothelial integrity, further strengthening the applicability of this animal model to clinical settings.

Conclusions—

Our findings demonstrate that Sox17 deficiency in mouse can induce IA under hypertensive conditions, suggesting Sox17 deficiency as a potential genetic factor for IA formation. The Sox17 -deficient mouse model provides a novel platform to develop therapeutics for incurable IA.

The UKNEQAS scheme for cerebrospinal fluid haem pigments: a paradigm for service improvement

We describe the programme of an established External Quality Assurance (EQA) provider and a Specialist Advisory Group (SAG) to develop a successful EQA scheme for cerebrospinal fluid (CSF) haem pigments as an example of a professionally led, unfunded initiative with the real potential to benefit patients.

Within three years, we had assured sample stability, stoichiometry, and published best practice guidelines, enabling both analytical results and interpretation to be assessed and reported with an educative summary of the desired responses. Misclassification scoring of analysis and interpretation was introduced. Following audit, guidelines were modified and republished. The outcomes were as follows: Participant numbers increased from 63 at inception to 150 10 years later; The percentage of participants using visual inspection, a poor practice indicator, decreased from 27% to less than 1%; In all, 94–100% of participants consistently detected minor increases in bilirubin over the last four years of the scheme; More than 93% of participants were able to interpret analytical results linked to straightforward clinical scenarios; Misclassification scoring demonstrated that more complex scenarios repeatedly posed problems and is the next challenge to address. Scheme success is attributed to the experience of the operator and the formation of a voluntary expert advisory group, with both concerned to advance science and patient safety and thus contribute unpaid time and effort in order to succeed. In times of fiscal constraint, such resource may not be so readily available, yet is a vital part of continuous quality improvement for the benefit of patients.

What is the role of cerebrospinal fluid ferritin in the diagnosis of subarachnoid haemorrhage in computed tomography-negative patients?

Background

Spectrophotometry of cerebrospinal fluid (CSF) for bilirubin is the recommended method for investigation in suspected cases of subarachnoid haemorrhage (SAH), when a computed tomography (CT) of the head is negative for blood. There is a potential need for a simpler alternative. Measurement of CSF ferritin might fulfil this need.

Method

We have measured ferritin in the CSF from 252 patients with suspected SAH who were negative on a CT of the head for blood, recruited on a consecutive intention to recruit basis from four centres. CSF spectrophotometry was performed on all samples. A positive outcome was taken as an aneurysm found on angiography that was treated or a discharge diagnosis of non-aneurysmal SAH.

Results

A final diagnosis of aneurysmal SAH was made in six patients, an arteriovenous malformation in one and non-aneurysmal SAH in nine. Receiver operating characteristic (ROC) analysis showed that at 6.4 μg/L, sensitivity, specificity, positive and negative predictive values were 1.0, 0.48, 0.12 and 1.0, respectively. At 12 μg/L, these values were 0.81, 0.91, 0.38 and 0.98, respectively.

Conclusions

At an appropriate negative predictive value (1.0) for a rule-out test, ferritin has too low a specificity to function as a stand-alone test and we cannot recommend it as an initial screen to be followed by spectrophotometry.