Dissection of both frontal and parietal branches of the superficial temporal artery for bypass surgery through a single linear skin incision

BACKGROUND

Double superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery has typically involved more than one linear incision. In this report, we demonstrate how the procedure can be performed through a single linear skin incision over the parietal branch of the STA.

METHODS

Initial dissection of the parietal branch and creation of a subcutaneous cavity along the frontal branch were performed using the conventional microscopic method. Detailed additional dissection and isolation of the frontal branch were accomplished with the aid of an endoscopic retractor.

RESULTS

This procedure was performed in five patients for harvesting of approximately 8- and 5-cm lengths of the parietal and frontal branches, respectively. The resultant lengths of the harvested vessels were sufficient for anastomotic revascularization of MCA recipient arteries in both the frontal and temporal lobes.

CONCLUSION

This method can be safely performed with achievement of a less invasive dissection of the STA and an overall improved cosmetic outcome.

Comparison of two policies for induction of labour postdates

The objective of this study was to compare maternal and midwifery manpower effects of policies for induction of labour (IOL) postdates, using a retrospective cohort design, in a level two maternity unit in a district hospital in South-West England. Primary outcome measures included mode of delivery, admission-delivery interval, midwifery manpower use. Group I consisted of 124 women who underwent IOL at 40+10. Group II were 104 women who underwent IOL at 42 weeks' gestation and 123 women who laboured spontaneously between 40+10 and 42 weeks' gestation. The nulliparous women had a shorter admission-delivery interval when induction was planned for 42 weeks, compared with 40+10 (p = 0.003), and required less frequent use of syntocinon (p = 0.04) and of continuous fetal monitoring (p = 0.02). The caesarean rate was higher in Group I than in Group II (p = 0.04) for nulliparous women only. The earlier induction policy was associated with a higher midwifery manpower requirement for nulliparae (p = 0.002). For parous women, the only difference was the greater use of oxytocin in labour. There was no difference between the groups in duration of labour, analgesia, Apgar scores, admission to neonatal care and meconium aspiration. In conclusion, delaying planned induction by three days was associated with lower medicalisation of labour and manpower needs for nulliparous women.

Stationary digital breast tomosynthesis with distributed field emission X-ray tube

Tomosynthesis requires projection images from different viewing angles. Using a distributed x-ray source this can be achieved without mechanical motion of the source with the potential for faster image acquisition speed. A distributed x-ray tube has been designed and manufactured specifically for breast tomosynthesis. The x-ray tube consists of 31 field emission x-ray sources with an angular range of 30°. The total dose is up to 100mAs with an energy range between 27 and 45 kVp. We discuss the source geometry and results from the characterization of the first prototype. The x-ray tube uses field emission cathodes based on carbon nanotubes (CNT) as electron source. Prior to the manufacturing of the sealed x-ray tube extensive testing on the field emission cathodes has been performed to verify the requirements for commercial tomosynthesis systems in terms of emission current, focal spot size and tube lifetime.

Neurenteric cyst of the lower clivus

OBJECTIVE

Neurenteric cysts (NCs) typically arise as benign ventral intradural extramedullary developmental malformations of the spine which contain heterotopic epithelium resembling the intestinal or respiratory tracts. Intracerebral NCs are extremely rare, though the frequency of symptomatic reports and incidental findings is increasing, perhaps because of advances in neuroimaging. Recognition of the unique radiographic and histopathologic features of this entity is of growing importance in the treatment of cysts of the neural axis. We present an unusual case of an NC arising at the lower clivus.

CLINICAL PRESENTATION

A 58-year-old man presented with occipitalgia, diplopia, a bilateral hearing deficit, and mild dysphagia. Computed tomography and magnetic resonance imaging demonstrated a 5 x 2 x 3-cm extra-axial cystic midline mass anterior to the brainstem at the lower clivus with posterior cyst wall enhancement.

INTERVENTION

The patient underwent a left lateral suboccipital total macroscopic resection of the lesion. Microscopic examination and histopathologic findings were consistent with a diagnosis of NC.

CONCLUSION

We describe the clinical presentation, imaging, and histopathologic characteristics, and discuss the diagnosis and surgical treatment of this rare lesion and related pathologic entities. Because of the remote possibility of delayed recurrence, even in cases of apparent total cyst wall removal, long-term serial imaging and a consideration of reoperation for recurrences is advisable.

Literature-based priors for gene regulatory networks

MOTIVATION

The use of prior knowledge to improve gene regulatory network modelling has often been proposed. In this article we present the first research on the massive incorporation of prior knowledge from literature for Bayesian network learning of gene networks. As the publication rate of scientific papers grows, updating online databases, which have been proposed as potential prior knowledge in past research, becomes increasingly challenging. The novelty of our approach lies in the use of gene-pair association scores that describe the overlap in the contexts in which the genes are mentioned, generated from a large database of scientific literature, harnessing the information contained in a huge number of documents into a simple, clear format.

RESULTS

We present a method to transform such literature-based gene association scores to network prior probabilities, and apply it to learn gene sub-networks for yeast, Escherichia coli and Human organisms. We also investigate the effect of weighting the influence of the prior knowledge. Our findings show that literature-based priors can improve both the number of true regulatory interactions present in the network and the accuracy of expression value prediction on genes, in comparison to a network learnt solely from expression data. Networks learnt with priors also show an improved biological interpretation, with identified subnetworks that coincide with known biological pathways.

Spontaneous epidural pneumocephalus

A 20-year-old male presented with an extremely rare spontaneous epidural pneumocephalus which was successfully treated by a single neurosurgical intervention. The patient had a habit of nose blowing and a 1-year history of progressive headache and nausea. Cranial computed tomography (CT) revealed a 2 x 7 cm right temporo-occipital epidural pneumocephalus with extensive hyperpneumatization of the mastoid cells. Right temporo-occipital craniotomy with a right superficial temporal artery and vein flap repair resulted in radiographic resolution of the pneumocephalus, and he remained neurologically free of symptoms at 1-year follow-up examination. Early identification and monitoring of symptomatic pneumocephalus followed by decompression and prevention of infection via closure of the bone defect can avoid possible serious consequences. The underlying mechanisms may involve a congenital petrous bone defect and a ball-valve effect due to excessive nose blowing in our case.

Does patient position influence Doppler signal quality from the USCOM ultrasonic cardiac output monitor?

BACKGROUND

The USCOM1A continuous wave cardiac output monitor (USCOM Pty Ltd., Sydney, NSW, Australia) is a novel Doppler-based device used to measure cardiac output noninvasively. The proper alignment of the transducer, and hence the ultrasound beam to the aortic or pulmonary outflow tracts, is essential to acquire accurate measurements and often much time is spent on transducer and/or patient positioning. In this prospective, observational, crossover study, we investigated the effect of patient positioning on the acquisition of cardiac output measurement with USCOM1A.

METHODS

We measured cardiac output using USCOM1A in 30 healthy adult volunteers, each in five different positions: sitting, supine, Trendelenburg (20 degrees), left lateral tilt (20 degrees), and right lateral tilt (20 degrees) and compared the time required to obtain acceptable measurements. We also compared the quality of the Doppler signal obtained in these positions using a scoring system designed for this study.

RESULTS

There was a higher rate of failed measurement, the mean time to obtain the first acceptable measurement was prolonged and the optimal measurement obtained within a 5-min period was of a lower quality in the sitting position compared with the other four positions.

CONCLUSIONS

Our results suggested the sitting position is the least suitable and least reliable position in which to perform cardiac output measurements using USCOM1A compared with the supine, Trendelenburg (20 degrees), left lateral tilt (20 degrees), and right lateral tilt (20 degrees) positions.

Intradural microsurgery and extradural gamma knife surgery for hypoglossal schwannoma: case report and review of the literature

There have been only 26 cases of hypoglossal schwannomas reported to originate intradurally and extend extradurally into the hypoglossal canal. This 31-year-old mother of two children presented with a 5-day history of progressive headache, nausea, vomiting and vertigo. Her neurological exam was significant for nystagmus and left tongue deviation with marked atrophy. An initial head CT revealed extensive left hypoglossal canal erosion with 4th ventricle compression. T1-weighted MR images with contrast revealed a 4x3 cm left cerebellopontine angle non-homogeneously enhancing mass with an intracranial cystic component and prominent extension into the eroded hypoglossal canal. A left lateral suboccipital craniotomy was performed for subtotal microsurgical resection of the intradural posterior fossa mass. A schwannoma was diagnosed after resection and gamma knife surgery (GKS) was performed three months later for the extradural residual tumor without further deficits. This is a rare report of a hypoglossal schwannoma in a young patient who was treated with a multimodality approach in order to minimize risks. A review of the literature and discussion of the respective benefits of microsurgery versus GKS and long-term follow-up issues are presented.

Remote cerebellar hemorrhage after supratentorial unruptured aneurysmal surgery: report of three cases

We report three cases of remote cerebellar hemorrhage that developed after supratentorial unruptured aneurysmal surgery. In all cases, digital subtraction angiography was performed before each operation in order to rule out other vascular abnormalities, especially around the operative field or the posterior circulation. In addition, all patients were screened for any previous history of bleeding tendencies or other related medical disorders. Each patient underwent clipping surgery via the pterional approach. Remote cerebellar hemorrhage was identified on post-operative computed tomographic scans. In all cases, there was no evidence of significant associated long-term morbidity. A consideration of the possible pathophysiologic mechanisms underlying these post-operative remote cerebellar hemorrhages and suggested strategies for avoiding such complications are discussed.

A neurotoxinological approach to the treatment of obstructive sleep apnoea

Current treatment approaches to the problem of obstructive sleep apnoea (OSA) have limitations. Specifically, invasive anatomical-based surgery and dental appliances typically do not alleviate obstruction at an acceptable rate, and compliance to continuous positive airway pressure (CPAP) devices is frequently suboptimal. Neurotoxinological treatment approaches are widespread in the field of medicine, but as yet have not been evaluated as a treatment for sleep-disordered breathing. In this review, it is argued that despite widespread recognition of the loss of upper airway (UA) muscular tone and/or reflexes in the expression of OSA, most treatment interventions to date have focused on anatomical principles alone. Several hypothesised neurotoxinological interventions aimed at either enhancing UA neuromuscular tone and/or reflexes are proposed, and some preliminary data is presented. Although in its early infancy, with considerable toxicity studies in animals yet to be done, a neurotoxinological approach to the problem of OSA holds promise as a future treatment, with the potential for both high effectiveness and patient compliance.

Huge Arachnoid Cyst of the Occipital Cerebral Convexity-Case Report-

A 68-year-old woman presented with a rare huge right occipital cystic lesion manifesting as progressive left hemiplegia. Cranial computed tomography revealed a 4 x 7 cm right occipital lobe thin-walled cyst with midline shift and compression of the ipsilateral ventricle. The patient underwent a single burr hole operation for cystography and delineation of the cyst anatomy, then a separate right parieto-occipital craniotomy with complete cyst evacuation, corticotomy, and ventriculostomy. The presumptive diagnosis was arachnoid cyst. The symptoms had completely resolved by 4 months after surgery with nearly normal neuroimaging appearance after 7 months. Cystography followed by craniotomy and ventriculostomy may be effective for supratentorial arachnoid cysts.

Transient Occipitotemporal Subcortical Diffusion-Weighted Magnetic Resonance Imaging Abnormalities Associated With Status Epilepticus-Case Report-

A 30-year-old man presented with a generalized seizure manifesting as decreased consciousness. Diffusion-weighted magnetic resonance imaging showed transient areas of high intensity in the gray and subcortical white matter of the left occipital and temporal lobes. The lesions did not reflect the vascular territories. After a period of over 2 weeks, his consciousness level improved associated with reduced intensity of the abnormal areas. These findings suggest that seizure induced reversible cytotoxic and vasogenic edema. Transient diffusion-weighted magnetic resonance imaging abnormalities may be associated with generalized seizures and the intensity may reflect the clinical condition.

Organized tooth-specific cellular differentiation stimulated by BMP4

Mammalian teeth develop on the oral surface of the first pharyngeal arch by a series of reciprocal interactions between epithelial and mesenchymal cells. The embryonic first pharyngeal arch oral epithelium is able to induce tooth formation when combined with mesenchymal cells from the second pharyngeal arch, a region devoid of tooth development. Second pharyngeal arch mesenchyme is thus competent to form teeth if provided with the correct signals. First-arch oral epithelium expresses several signaling molecules that could be potential inducers of tooth development, including BMP4. The addition of BMP4 to intact second-arch explants resulted in the development of organized structures containing layers of cells that express marker genes of tooth-specific cells, odontoblasts and ameloblasts. Thus, although overt tooth development did not occur, BMP4 has the ability to stimulate organized differentiation of epithelial- and mesenchymal-derived dental-specific cells from non-dental primordia.

Direct ANP inhibition of hypoxia-induced inflammatory pathways in pulmonary microvascular and macrovascular endothelial monolayers

Atrial natriuretic peptide (ANP) has been shown to reduce hypoxia-induced pulmonary vascular leak in vivo, but no explanation of a mechanism has been offered other than its vasodilatory and natriuretic actions. Recently, data have shown that ANP can protect endothelial barrier functions in TNF-alpha-stimulated human umbilical vein endothelial cells. Therefore, we hypothesized that ANP actions would inhibit pulmonary vascular leak by inhibition of TNF-alpha secretion and F-actin formation. Bovine pulmonary microvascular (MVEC) and macrovascular endothelial cell (LEC) monolayers were stimulated with hypoxia, TNF-alpha, or bacterial endotoxin (LPS) in the presence or absence of ANP, and albumin flux, NF-kappa B activation, TNF-alpha secretion, p38 mitogen-activated protein kinase (MAPK), and F-actin (stress fiber) formation were assessed. In Transwell cultures, ANP reduced hypoxia-induced permeability in MVEC and TNF-alpha-induced permeability in MVEC and LEC. ANP inhibited hypoxia and LPS increased NF-kappa B activation and TNF-alpha synthesis in MVEC and LEC. Hypoxia decreased activation of p38 MAPK in MVEC but increased activation of p38 MAPK and stress fiber formation in LEC; TNF-alpha had the opposite effect. ANP inhibited an activation of p38 MAPK in MVEC or LEC. These data indicate that in endothelial cell monolayers, hypoxia activates a signal cascade analogous to that initiated by inflammatory agents, and ANP has a direct cytoprotective effect on the pulmonary endothelium other than its vasodilatory and natriuretic properties. Furthermore, our data show that MVEC and LEC respond differently to hypoxia, TNF-alpha-stimulation, and ANP treatment.

Assessing inhibitory control: a revised approach to the stop signal task

The stop signal task (stop task) is designed to assess inhibitory control and is a frequently used research tool in clinical disorders such as ADHD and schizophrenia. Previous methods of setting stop signal delay and of assessing inhibitory control are problematic. The current study reports two modifications that improve the task as a measure of inhibitory control. The first modification was to set stop signal delays proportional to go mean reaction time (go MRT) to better account for inter-subject variability in go MRT. Twenty-eight normal children were tested, and all standard, stop task dependent measures were obtained when delays were set by this method. The second modification was to calculate a novel dependent measure called the area of inhibition (AOI) which provides a more complete measure of inhibitory control than the slope of the relative finishing time z-scores (ZRFT-slope). Implications for the assessment of inhibitory control in clinical populations are discussed.