Internal border zone injury predicts the functional outcome of acute MCA stroke patients

BACKGROUND AND PURPOSE

Classification of deep (D), superficial (S) MCA territories and their junctional vascular area (the internal border zone, IBZ) can help to identify patients most likely to benefit from aggressive reperfusion therapy after stroke. We tested the prognostic value of an IBZ injury compared to DWI-ASPECTS and infarct volume.

MATERIALS AND METHODS

DW lesions of 168 patients with acute (4.2±6.5 h) MCA strokes were retrospectively examined and manually delineated. Patients with haemorrhagic transformation or other neurological diseases were excluded. Clinical data were recorded within 24 h following symptom onset and 48 h for patients who benefited from reperfusion therapy. The occurrence of an IBZ injury was determined using a standardized stereotaxic atlas. Performance to predict a good outcome (mRS<3 at 3 months) was estimated through ROC curves for DWI-ASPECTS≤6, lesion volume≥100 mL and IBZ injury. Logistic regression models were performed to estimate independent outcomes for infarct volume and IBZ injury.

RESULTS

Infarcts involving the IBZ were larger (94.9±98.8 mL vs. 30.2±31.3 mL), had higher NIHSS (13.8±7.2 vs. 7.2±5.7), more frequent MCA occlusions (64.9% vs. 28.3%), and worse outcomes (mRS 3.0±1.8 vs. 1.9±1.7), and were less responsive to IVtPA (34±47% vs. 55±48% of NIHSS improvement). The area under the ROC curves was comparable between the occurrence of IBZ injury (0.651), ASPECTS≤6 (0.657) and volume≥100 mL (0.629). Logistic regression analyses showed an independent effect of an IBZ injury, especially for superficial MCA strokes and for patients who benefited from reperfusion therapy.

CONCLUSION

An IBZ injury is an early and independent marker of stroke severity, functional prognosis and treatment responsiveness.

Spinal Arachnoid Web: A didactic report of two cases with clinical, radiological, surgical and pathological correlations

BACKGROUND

Arachnoid web (AW) is a rare but probably underestimated cause of spinal cord injury that is complex to diagnose due to subtle MRI findings and similarities to other better-known diseases such as arachnoid cyst (AC) or transdural spinal cord herniation (TSCH). Increased recognition of AW is mandatory since delay in diagnosis can lead to potentially serious neurological sequelae.

CASE PRESENTATIONS

We report two additional cases of AW for didactic purposes, with special emphasis on the distinctive MRI and intraoperative findings. Both patients presented with progressively worsening neurological symptoms, including proprioceptive ataxia, motor weakness, numbness and neuropathic pain. The diagnosis of AW was suspected on the basis of specific MRI criteria, especially the so-called "scalpel sign". Formal confirmation of the diagnosis was obtained in two patients that were managed surgically. Postoperative follow-up demonstrated significant functional recovery.

DISCUSSION

There is a need for better recognition of AW by the medical community. Careful analysis of MRI semiology is crucial for the distinction between AW, AC and TSCH. Prompt and accurate diagnosis is mandatory to conserve functional prognosis, since appropriate surgical treatment with AW resection is curative, halting or even resolving the neurological symptoms.

Abortion-prone mating influences placental antioxidant status and adversely affects placental and foetal development

Oxidative stress is associated with decreased female fertility and adversely affects prenatal development. Mammalian cells have developed a network of enzymatic and non-enzymatic antioxidant defence systems to prevent oxidative stress. Little attention has been paid to the antioxidative pathways in placentas of normal and disturbed pregnancies, leaving a gap in our knowledge about the role of antioxidants in the control of foeto-placental development. The challenges in studying early human pregnancy can partly be overcome by designing animal models of abnormal pregnancy. We aimed to determine whether the antioxidant status of placentas from the CBA/J × DBA/2 abortion-prone pregnant mice differed from that of normal pregnant mice. The foetal/placental weight ratio was lower in abortion-prone matings compared with that in non-abortion-prone matings. The increased placental malondialdehyde (MDA) content, the end products of lipid peroxidation, with concomitants alterations in placental antioxidants, namely copper-zinc containing superoxide dismutase (SOD1), manganese containing (SOD2), glutathione peroxidases (GPX), glutathione reductase (GR) and catalase (CAT) activities may be involved in placental and foetal growth restriction. We show that placental oxidative stress is linked with poor prenatal development and pregnancy losses in CBA/J × DBA/2 mice matings. This animal model may be useful in the evaluation of nutritional antioxidant therapies for oxidative stress and associated prenatal developmental disorders.

“When can I return to driving?”

Clinicians are often asked by patients, “When can I drive again?” after lower limb injury or surgery. This question is difficult to answer in the absence of any guidelines. This review aims to collate the currently available evidence and discuss the factors that influence the decision to allow a patient to return to driving. Medline, Web of Science, Scopus, and EMBASE were searched using the following terms: ‘brake reaction time’, ‘brake response time’, ‘braking force’, ‘brake pedal force’, ‘resume driving’, ‘rate of application of force’, ‘driving after injury’, ‘joint replacement and driving’, and ‘fracture and driving’. Of the relevant literature identified, most studies used the brake reaction time and total brake time as the outcome measures. Varying recovery periods were proposed based on the type and severity of injury or surgery. Surveys of the Driver and Vehicle Licensing Agency, the Police, insurance companies in the United Kingdom and Orthopaedic Surgeons offered a variety of opinions.

There is currently insufficient evidence for any authoritative body to determine fitness to drive. The lack of guidance could result in patients being withheld from driving for longer than is necessary, or returning to driving while still unsafe.

Cite this article: Bone Joint J 2013;95-B:290–4.

A haptic guidance tool for CT-directed percutaneous interventions

We have developed a new navigation approach for computer-assisted interventional radiology. Our system combines a virtual reality display with high-fidelity haptic rendering to provide assistance and guidance of the medical gesture. Specifically, the system is designed to improve the accuracy of blind needle placement within tissues. The proposed technique actively helps the surgeon while keeping him in control of the procedure. We have recently developed an experimental setup for CT-guided biopsy. The setup features a high-precision haptic device connected to the biopsy needle, combined with a graphical interface. The haptic system guides the surgeon's hand to the target tissue based on CT data, whereas a real-time, graphical visualization of the tool trajectory provides navigation information. The setup requires rigid registration of the patient with respect to the haptic interface. Tests have been performed in the presence of radiologists to validate the proposed concept, and early results show that the system is easy to use and requires little training. We are planning to conduct clinical testing in the near future to quantitatively assess system performance.

A non-contact mouse for surgeon-computer interaction

We have developed a system that uses computer vision to replace standard computer mouse functions with hand gestures. The system is designed to enable non-contact human-computer interaction (HCI), so that surgeons will be able to make more effective use of computers during surgery. In this paper, we begin by discussing the need for non-contact computer interfaces in the operating room. We then describe the design of our non-contact mouse system, focusing on the techniques used for hand detection, tracking, and gesture recognition. Finally, we present preliminary results from testing and planned future work.

A pharmacokinetic model to predict the PK interaction of L-dopa and benserazide in rats

PURPOSE

To study the PK interaction of L-dopa/benserazide in rats.

METHODS

Male rats received a single oral dose of 80 mg/kg L-dopa or 20 mg/kg benserazide or 80/20 mg/kg L-dopa/benserazide. Based on plasma concentrations the kinetics of L-dopa, 3-O-methyldopa (3-OMD), benserazide, and its metabolite Ro 04-5127 were characterized by noncompartmental analysis and a compartmental model where total L-dopa clearance was the sum of the clearances mediated by amino-acid-decarboxylase (AADC), catechol-O-methyltransferase and other enzymes. In the model Ro 04-5127 inhibited competitively the L-dopa clearance by AADC.

RESULTS

The coadministration of L-dopa/benserazide resulted in a major increase in systemic exposure to L-dopa and 3-OMD and a decrease in L-dopa clearance. The compartmental model allowed an adequate description of the observed L-dopa and 3-OMD concentrations in the absence and presence of benserazide. It had an advantage over noncompartmental analysis because it could describe the temporal change of inhibition and recovery of AADC.

CONCLUSIONS

Our study is the first investigation where the kinetics of benserazide and Ro 04-5127 have been described by a compartmental model. The L-dopa/benserazide model allowed a mechanism-based view of the L-dopa/benserazide interaction and supports the hypothesis that Ro 04-5127 is the primary active metabolite of benserazide.

Moclobemide, a substrate of CYP2C19 and an inhibitor of CYP2C19, CYP2D6, and CYP1A2: a panel study

The reversible monoamine oxidase A inhibitor moclobemide was given in single (300 mg) and multiple doses (600 mg/day) to 11 male and four female healthy volunteers (age range, 23 to 27) who were either poor metabolizers of S-mephenytoin (n = 7) or extensive metabolizers of S-mephenytoin (n = 8). All were extensive metabolizers of sparteine. Poor metabolizers of S-mephenytoin had lower moclobemide clearance values (median, single dose: 16.1 versus 43.2 L.hr-1; steady state: 13.4 versus 22.1 L.hr-1) and longer moclobemide half-life values (median, single dose: 4.0 versus 1.8 hours; steady state: 5.1 versus 2.7 hours) than extensive metabolizers of S-mephenytoin. The plasma levels of a metabolite formed by C-hydroxylation (Ro 12-8095) were lower in poor metabolizers of S-mephenytoin than in extensive metabolizers of S-mephenytoin. Moclobemide thus partially undergoes oxidative metabolism by way of the polymorphic CYP2C19. A combined mephenytoin, sparteine, and caffeine test performed before, during, and after multiple dosing of moclobemide showed changes in the metabolic indexes compatible with a reversible inhibition of oxidation by way of the corresponding CYP enzymes--CYP2C19, CYP2D6, and CYP1A2--during moclobemide treatment.