Findings of the International Subarachnoid Aneurysm Trial and the National Study of Subarachnoid Haemorrhage in context.

Concern has been expressed about the applicability of the findings of the International Subarachnoid Aneurysm Trial (ISAT) with respect to the relative effects on outcome of coiling and clipping. It has been suggested that the findings of the National Study of Subarachnoid Haemorrhage may have greater relevance for neurosurgical practice. The objective of this paper was to interpret the findings of these two studies in the context of differences in their study populations, design, execution and analysis. Because of differences in design and analysis, the findings of the two studies are not directly comparable. The ISAT analysed all randomized patients by intention-to-treat, including some who did not undergo a repair, and obtained the primary outcome for 99% of participants. The National Study only analysed participants who underwent clipping or coiling, according to the method of repair, and obtained the primary outcome for 91% of participants. Time to repair was also considered differently in the two studies. The comparison between coiling and clipping was susceptible to confounding in the National Study, but not in the ISAT. The two study populations differed to some extent, but inspection of these differences does not support the view that coiling was applied inappropriately in the National Study. Therefore, there are many reasons why the two studies estimated different sizes of effect. The possibility that there were real, systematic differences in practice between the ISAT and the National Study cannot be ruled out, but such explanations must be seen in the context of other explanations relating to chance, differences in design or analysis, or confounding

A review of the tractive performance of wheeled tractors and soil management in lowland intensive rice production.

This paper reviews the cultivation practices and tractive performance using wheeled tractors, and how these interact with soil management, in lowland intensive rice production. The paper explores the issues of long term sustainable soil use, the energy inputs required, environmental impact and changes in approach to agronomy and links these to the tractor operations carried out as part of rice production. The paddy soil environment demonstrates very significant changes in soil properties with depth, in particular soil density, penetrometer resistance, soil structure and pore interconnectivity, water content and movement, and soil biology. This is related to the management of the soil hard pan in relation to machinery operations and machinery use. One of the issues appears to be that the hard pan can be deeper than required with consequently unnecessarily high energy inputs. The tractive performance of wheeled tractors on different surface conditions is considered with respect to tractive efficiency and maintenance of a soil hard pan that has the required characteristics for sustainable production. Alternatives to conventional tyres, cage wheels and tracks, are considered. The cultivation operations are evaluated in relation to soil management, crop requirements and energy use. Variation in hard pan characteristics may be disadvantageous and provides opportunities for precision operations

Length of carotid stenosis predicts peri-procedural stroke or death and restenosis in patients randomized to endovascular treatment or endarterectomy.

BACKGROUND: The anatomy of carotid stenosis may influence the outcome of endovascular treatment or carotid endarterectomy. Whether anatomy favors one treatment over the other in terms of safety or efficacy has not been investigated in randomized trials. METHODS: In 414 patients with mostly symptomatic carotid stenosis randomized to endovascular treatment (angioplasty or stenting; n = 213) or carotid endarterectomy (n = 211) in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), the degree and length of stenosis and plaque surface irregularity were assessed on baseline intraarterial angiography. Outcome measures were stroke or death occurring between randomization and 30 days after treatment, and ipsilateral stroke and restenosis ≥50% during follow-up. RESULTS: Carotid stenosis longer than 0.65 times the common carotid artery diameter was associated with increased risk of peri-procedural stroke or death after both endovascular treatment [odds ratio 2.79 (1.17-6.65), P = 0.02] and carotid endarterectomy [2.43 (1.03-5.73), P = 0.04], and with increased long-term risk of restenosis in endovascular treatment [hazard ratio 1.68 (1.12-2.53), P = 0.01]. The excess in restenosis after endovascular treatment compared with carotid endarterectomy was significantly greater in patients with long stenosis than with short stenosis at baseline (interaction P = 0.003). Results remained significant after multivariate adjustment. No associations were found for degree of stenosis and plaque surface. CONCLUSIONS: Increasing stenosis length is an independent risk factor for peri-procedural stroke or death in endovascular treatment and carotid endarterectomy, without favoring one treatment over the other. However, the excess restenosis rate after endovascular treatment compared with carotid endarterectomy increases with longer stenosis at baseline. Stenosis length merits further investigation in carotid revascularisation trials

Surgical Trial in Lobar Intracerebral Haemorrhage (STICH II) Protocol

<p>Abstract</p> <p>Background</p> <p>Within the spectrum of spontaneous intracerebral haemorrhage there are some patients with large or space occupying haemorrhage who require surgery for neurological deterioration and others with small haematomas who should be managed conservatively. There is equipoise about the management of patients between these two extremes. In particular there is some evidence that patients with lobar haematomas and no intraventricular haemorrhage might benefit from haematoma evacuation. The STICH II study will establish whether a policy of earlier surgical evacuation of the haematoma in selected patients will improve outcome compared to a policy of initial conservative treatment.</p> <p>Methods/Design</p> <p>an international multicentre randomised parallel group trial. Only patients for whom the treating neurosurgeon is in equipoise about the benefits of early craniotomy compared to initial conservative treatment are eligible. All patients must have a CT scan confirming spontaneous lobar intracerebral haemorrhage (≤1 cm from the cortex surface of the brain and 10-100 ml in volume). Any clotting or coagulation problems must be corrected and randomisation must take place within 48 hours of ictus. With 600 patients, the study will be able to demonstrate a 12% benefit from surgery (2p < 0.05) with 80% power.</p> <p>Stratified randomisation is undertaken using a central 24 hour randomisation service accessed by telephone or web. Patients randomised to early surgery should have the operation within 12 hours. Information about the status (Glasgow Coma Score and focal signs) of all patients through the first five days of their trial progress is also collected in addition to another CT scan at about five days (+/- 2 days). Outcome is measured at six months via a postal questionnaire to the patient. Primary outcome is death or severe disability defined using a prognosis based 8 point Glasgow Outcome Scale. Secondary outcomes include: Mortality, Rankin, Barthel, EuroQol, and Survival.</p> <p>Trial Registration</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/ISRCTN22153967">ISRCTN22153967</a></p

A new MRI rating scale for progressive supranuclear palsy and multiple system atrophy: validity and reliability

AIM To evaluate a standardised MRI acquisition protocol and a new image rating scale for disease severity in patients with progressive supranuclear palsy (PSP) and multiple systems atrophy (MSA) in a large multicentre study. METHODS The MRI protocol consisted of two-dimensional sagittal and axial T1, axial PD, and axial and coronal T2 weighted acquisitions. The 32 item ordinal scale evaluated abnormalities within the basal ganglia and posterior fossa, blind to diagnosis. Among 760 patients in the study population (PSP = 362, MSA = 398), 627 had per protocol images (PSP = 297, MSA = 330). Intra-rater (n = 60) and inter-rater (n = 555) reliability were assessed through Cohen's statistic, and scale structure through principal component analysis (PCA) (n = 441). Internal consistency and reliability were checked. Discriminant and predictive validity of extracted factors and total scores were tested for disease severity as per clinical diagnosis. RESULTS Intra-rater and inter-rater reliability were acceptable for 25 (78%) of the items scored (≥ 0.41). PCA revealed four meaningful clusters of covarying parameters (factor (F) F1: brainstem and cerebellum; F2: midbrain; F3: putamen; F4: other basal ganglia) with good to excellent internal consistency (Cronbach α 0.75-0.93) and moderate to excellent reliability (intraclass coefficient: F1: 0.92; F2: 0.79; F3: 0.71; F4: 0.49). The total score significantly discriminated for disease severity or diagnosis; factorial scores differentially discriminated for disease severity according to diagnosis (PSP: F1-F2; MSA: F2-F3). The total score was significantly related to survival in PSP (p<0.0007) or MSA (p<0.0005), indicating good predictive validity. CONCLUSIONS The scale is suitable for use in the context of multicentre studies and can reliably and consistently measure MRI abnormalities in PSP and MSA. Clinical Trial Registration Number The study protocol was filed in the open clinical trial registry (http://www.clinicaltrials.gov) with ID No NCT00211224

Emerging mechanisms of dynein transport in the cytoplasm versus the cilium

Two classes of dynein power long-distance cargo transport in different cellular contexts. Cytoplasmic dynein-1 is responsible for the majority of transport toward microtubule minus ends in the cell interior. Dynein-2, also known as intraflagellar transport dynein, moves cargoes along the axoneme of eukaryotic cilia and flagella. Both dyneins operate as large ATP-driven motor complexes, whose dysfunction is associated with a group of human disorders. But how similar are their mechanisms of action and regulation? To examine this question, this review focuses on recent advances in dynein-1 and -2 research, and probes to what extent the emerging principles of dynein-1 transport could apply to or differ from those of the less well-understood dynein-2 mechanoenzyme