Emergency computed tomography for acute pelvic trauma: where is the bleeder?

Contrast medium extravasation at computed tomography (CT) is an accurate indicator of active haemorrhage in pelvic trauma. When this is present, potentially lifesaving surgical or endovascular treatment should be considered. Identification of the site or territory of haemorrhage is helpful for the interventional radiologist as it allows for focused angiographic evaluation and expedites haemostatic angio-embolisation. Even with thin-section arterial phase CT, tracing the bleeding vessel is not always possible and is often time consuming. We introduce a technique for predicting the bleeding vessel based on knowledge of the cross-sectional anatomical territory of the vessel as an alternative to tracing the vessel's course. Several case examples with digital subtraction angiography (DSA) correlation will be provided.

Dilemmas and diagnostic difficulties in meningioma.

This article will review the uncommon locations and morphological features of meningiomas, which are important to recognize in order to avoid misdiagnosis. Uncommon locations will be demonstrated at the cerebellopontine angle, pineal, optic, intraventricular, and intradiploic regions. Unusual imaging features including cysts, metaplastic changes, and peritumoural oedema will also be discussed.

Standard virtual biological parts: a repository of modular modeling components for synthetic biology.

MOTIVATION: Fabrication of synthetic biological systems is greatly enhanced by incorporating engineering design principles and techniques such as computer-aided design. To this end, the ongoing standardization of biological parts presents an opportunity to develop libraries of standard virtual parts in the form of mathematical models that can be combined to inform system design. RESULTS: We present an online Repository, populated with a collection of standardized models that can readily be recombined to model different biological systems using the inherent modularity support of the CellML 1.1 model exchange format. The applicability of this approach is demonstrated by modeling gold-medal winning iGEM machines. AVAILABILITY AND IMPLEMENTATION: The Repository is available online as part of http://models.cellml.org. We hope to stimulate the worldwide community to reuse and extend the models therein, and contribute to the Repository of Standard Virtual Parts thus founded. Systems Model architecture information for the Systems Model described here, along with an additional example and a tutorial, is also available as Supplementary information. The example Systems Model from this manuscript can be found at http://models.cellml.org/workspace/bugbuster. The Template models used in the example can be found at http://models.cellml.org/workspace/SVP_Templates200906.

A genomewide suppressor and enhancer analysis of cdc13-1 reveals varied cellular processes influencing telomere capping in Saccharomyces cerevisiae.

In Saccharomyces cerevisiae, Cdc13 binds telomeric DNA to recruit telomerase and to "cap" chromosome ends. In temperature-sensitive cdc13-1 mutants telomeric DNA is degraded and cell-cycle progression is inhibited. To identify novel proteins and pathways that cap telomeres, or that respond to uncapped telomeres, we combined cdc13-1 with the yeast gene deletion collection and used high-throughput spot-test assays to measure growth. We identified 369 gene deletions, in eight different phenotypic classes, that reproducibly demonstrated subtle genetic interactions with the cdc13-1 mutation. As expected, we identified DNA damage checkpoint, nonsense-mediated decay and telomerase components in our screen. However, we also identified genes affecting casein kinase II activity, cell polarity, mRNA degradation, mitochondrial function, phosphate transport, iron transport, protein degradation, and other functions. We also identified a number of genes of previously unknown function that we term RTC, for restriction of telomere capping, or MTC, for maintenance of telomere capping. It seems likely that many of the newly identified pathways/processes that affect growth of budding yeast cdc13-1 mutants will play evolutionarily conserved roles at telomeres. The high-throughput spot-testing approach that we describe is generally applicable and could aid in understanding other aspects of eukaryotic cell biology.

Failure of downward gaze: the site and nature of the lesion.

We report four patients with paralysis of downward gaze but with intact upward gaze, including one with detailed clinico-pathological studies and another with a focal computerized axial tomographic (CT) scan abnormality confirming the presence of bilateral lesions of the dorsomedial red nucleus, including the fasciculus retroflexus. It is suggested that sudden, permanent selective failure of downward gaze accompanied by transient disturbance of consciousness is an embolic syndrome of the posterior thalamosubthalamic or rubral artery.

Painful oculomotor nerve palsy due to dural-cavernous sinus shunt.

Two patients presented with painful unilateral oculomotor nerve palsies without evidence of ocular congestion or hypoxia. They were initially thought to have posterior communicating or distal internal carotid aneurysms, but had, in fact, dural-cavernous sinus shunts, draining posteriorly into the inferior petrosal sinus. One patient later developed a moderately severe congestive ophthalmopathy, and repeated selective carotid arteriograms showed that the shunt was now draining anteriorly into the superior ophthalmic vein. In the other patient, the oculomotor nerve palsy resolved without the development of any further signs. These observations support the concept that dural-cavernous sinus shunts produce symptoms that are dependent on the direction of drainage from the shunt. It is clear that the direction of drainage can change and that thrombosis of the posterior cavernous sinus determines the direction of drainage. The exact mechanism of the cranial neuropathy is, however, unknown.

Clinical manifestations and radiologic findings in craniopharyngiomas in adults.

The clinical and histopathologic findings in two adults with craniopharyngioma emphasized the wide age range and diverse initial manifestations of this tumor. A retrospective clinical review of 49 additional patients substantiated these points and disclosed that over 40% were initially examined by ophthalmologists. The initial manifestations fell into four broad categories: (1) visual system abnormalities (77% of the cases), (2) headache (67%), (3) endocrinologic abnormalities (57%), and (4) mental status abnormalities (19%). The frequency of these manifestations varied slightly among different age groups. The radiologic features in the two patients described (a 75-year-old man and a 38-year-old woman) included a distinct appearance on computed tomographic scans. These craniopharyngioma were not calcified and were isodense without contrast but enhanced densely and uniformly with contrast, simulating an aneurysm of the circle of Willis.

Intravenous digital subtraction angiography in the diagnosis of brain death.

The diagnosis of brain death requires: (1) the performance of all appropriate and therapeutic procedures; (2) the presence of cerebral unresponsivity, apnea, dilated pupils, absent cephalic reflexes, and electrocerebral silence; and (3) if one of these criteria cannot be tested or is met imprecisely, the performance of a confirmatory test to demonstrate the absence of cerebral blood flow. Selective cerebral arteriography has been the most widely used method of assessing cerebral blood flow. Digital intravenous angiography was used as a means of evaluating cerebral blood flow, and it was found to be a useful confirmatory test in the diagnosis of brain death.

Vertebral artery dissection diagnosed with CT.

Vertebral artery dissection after neck manipulation has been well described. A case of bilateral vertebral artery dissection diagnosed with dynamic CT scanning of the neck is reported. The CT appearances and correlative angiographic and MR findings are presented.

Complications of surgery for arteriovenous malformations of the brain.

A series of 112 patients undergoing complete surgical resection of arteriovenous malformations (AVM's) of the brain between 1974 and 1990 were analyzed for complications and 12-month outcomes. The cohort consisted of 44 patients with small AVM's (< 2 cm in diameter), 43 patients with medium-sized AVM's (2 to 4 cm in diameter), and 25 patients with large AVM's (> 4 cm in diameter). There was a 3.6% series mortality rate and an 18% morbidity rate. One of the four deaths was caused by normal perfusion pressure breakthrough. Analysis of logistic regression found that the most important factor influencing the occurrence of complications in this series was AVM size (p = 0.005) and that the occurrence of complications (p < 0.001) and the neurological grade at the time of surgery (p < 0.004) both significantly contributed to the outcome at 12 months. This study stresses the importance of defining complications in terms of rigid criteria when analyzing AVM series in order to allow for a correct evaluation of the risk:benefit ratio of surgery. Furthermore, it emphasizes the need for a separate analysis of the importance of complications upon outcome.

Repair under cardiopulmonary bypass of giant internal carotid aneurysm following GDC embolization.

Endovascular embolization techniques have increased the complexity of aneurysm surgery in those lesions that have been incompletely obliterated. We report a case of giant cerebral aneurysm initially treated with Guglielmi detachable coils which required cardiopulmonary bypass for successful endoaneurysmorrhaphy.

Network approaches to the functional analysis of microbial proteins.

Large amounts of detailed biological data have been generated over the past few decades. Much of these data is freely available in over 1000 online databases; an enticing, but frustrating resource for microbiologists interested in a systems-level view of the structure and function of microbial cells. The frustration engendered by the need to trawl manually through hundreds of databases in order to accumulate information about a gene, protein, pathway, or organism of interest can be alleviated by the use of computational data integration to generated network views of the system of interest. Biological networks can be constructed from a single type of data, such as protein-protein binding information, or from data generated by multiple experimental approaches. In an integrated network, nodes usually represent genes or gene products, while edges represent some form of interaction between the nodes. Edges between nodes may be weighted to represent the probability that the edge exists in vivo. Networks may also be enriched with ontological annotations, facilitating both visual browsing and computational analysis via web service interfaces. In this review, we describe the construction, analysis of both single-data source and integrated networks, and their application to the inference of protein function in microbes.

Antisense transcription in the mammalian transcriptome.

Antisense transcription (transcription from the opposite strand to a protein-coding or sense strand) has been ascribed roles in gene regulation involving degradation of the corresponding sense transcripts (RNA interference), as well as gene silencing at the chromatin level. Global transcriptome analysis provides evidence that a large proportion of the genome can produce transcripts from both strands, and that antisense transcripts commonly link neighboring "genes" in complex loci into chains of linked transcriptional units. Expression profiling reveals frequent concordant regulation of sense/antisense pairs. We present experimental evidence that perturbation of an antisense RNA can alter the expression of sense messenger RNAs, suggesting that antisense transcription contributes to control of transcriptional outputs in mammals.

CT and nuclear medicine in screening for neurological disease.

Unit costs of computerized tomography (CT) in Australian hospital practice are considerably lower than those reported in the United States' literature, and not significantly higher than those of nuclear brain scanning which is at a threefold to fourfold disadvantage in false negative rates. CT is cost-effective not only in defining but in screening for neurological disease, and should replace radionuclide scans in both roles.

Optic neuritis and computed tomography.

A forty year old Lebanese man presented to Royal Prince Alfred Hospital with unilateral visual loss and disc oedema. Computed Tomography (CT) of his orbit demonstrated diffuse thickening and tortuosity consistent with an optic nerve tumour. Surgical exploration of the orbit was averted when the patient reported subjective visual improvement. Two months later, CT demonstrated an optic nerve which was well within normal limits.

Cranial magnetic resonance imaging in chronic demyelinating polyneuropathy.

Twenty one patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and five patients with chronic demyelinating polyneuropathy associated with benign monoclonal paraproteinaemia none of whom had signs or symptoms of central nervous system disease, had cranial magnetic resonance imaging (MRI) on a 1.5 Tesla unit. Areas of increased white matter signal intensity were seen in one of 10 patients aged less than 50 years and in five of 16 patients aged more than 50 years. In only two of the patients (8%), neither of whom had paraproteinaemia, did the appearance strongly suggest demyelination. The only clinical variable that predicted MRI changes was age (p less than 0.01).

Computerized tomographic findings in meningovascular syphilis: a case report.

Although angiographic findings of arterial narrowing have been detailed in several cases of meningovascular syphilis, very few descriptions of abnormal computerized tomographic (CT) findings have been reported. A case of multiple vascular infarcts detected on CT scan is described; syphilis is proposed as the probable cause of the vascular pathology.

Superior sagittal sinus thrombosis.

Seven cases of superior sagittal sinus thrombosis seen at Royal Prince Alfred Hospital over the 10 year period 1979 to 1989 have been reviewed. Diagnosis was confirmed by angiography, CT scan or autopsy. The average age was 33 years (16 to 47 years). Five of the patients were female and 2 male. On CT scan the 'empty delta' sign, present in 4 cases, was the most specific diagnostic feature. The underlying causes included primary thrombocythaemia, homocystinuria, post-angiographic investigation of an arteriovenous malformation, and oral contraceptives. In 2 cases no cause was found. Headache was the commonest and earliest symptom, being followed in frequency by convulsions and hemiparesis. Hemiparesis was the commonest sign observed, followed by papilloedema, cranial nerve palsies and impaired level of consciousness. Five of the patients developed signs and symptoms of raised intracranial pressure prior to the appearance of focal neurological deficits, mostly likely due to propagation of the thrombosis to cortical veins. There have been no controlled trials of therapy; however it is important to treat raised intracranial pressure rapidly and effectively, and although the role of anticoagulants remains controversial, their early use may be indicated when there is no radiological evidence of haemorrhage.