Ophthalmic diagnoses in the ED: optic neuritis

Optic neuritis is the most common cause of decreased vision due to optic nerve dysfunction in patients who are 20 to 40 years of age. Optic neuritis, or inflammation of the optic nerve, is primarily due to idiopathic demyelination. Demyelinative lesions seen in optic neuritis are not unlike those seen in plaque associated with multiple sclerosis. In fact, acute inflammatory demyelination of the optic nerve commonly occurs as an initial manifestation of multiple sclerosis. Key features of optic neuritis include a vision loss occurring over 1 to 10 days, color vision impairment, eye pain with motility, and an afferent pupillary defect. This significant diagnosis can be challenging to an emergency physician as it is relatively infrequently observed.     

Impact of infusion speed on the safety and effectiveness of prothrombin complex concentrate

Prothrombin complex concentrate (PCC) infusion is preferred for emergency reversal of coumarin therapy. Rapid infusion can potentially save crucial time; however, the possible impact of high infusion speed on PCC safety and effectiveness has not been delineated. In a prospective multinational clinical trial with 43 patients receiving PCC (Beriplex® P/N) for emergency reversal of coumarin therapy, infusion speeds were selected by the investigators. In a two-phase statistical analysis, the influence of baseline patient variables and dose on selected infusion speed was assessed. Then, the effect of infusion speed on reduction in international normalized ratio (INR) and on thrombogenicity marker pharmacokinetics was evaluated. Infusion speed ranged widely from 2.0 to 40.0 mL min^?1 with a median of 7.5 mL min^?1. Selection of infusion speed was not significantly influenced by gender, age, body mass index, presence of acute bleeding, indication for coumarin therapy, baseline INR, or PCC dose. Infusion speed was higher by a median of 2.2 mL min^?1 (95% confidence interval, 1.0–4.3 mL min^?1) among patients receiving Beriplex P/N volumes ≥80 mL compared with smaller infusion volumes. Infusion speed did not affect INR attained 30 min following PCC infusion. None of the evaluated thrombogenicity marker pharmacokinetic parameters was affected by infusion speed. Infusions in one patient with questionable hemostatic efficacy and another with a possibly PCC-related thromboembolic event were at moderate and slow speeds, respectively. This study provides the first direct evidence that Beriplex® P/N can be rapidly infused for emergency coumarin therapy reversal without altering safety or effectiveness.     

Classification of neural tumors in laboratory rodents, emphasizing the rat

Neoplasms of the nervous system, whether spontaneous or induced, are infrequent in laboratory rodents and very rare in other laboratory animal species. The morphology of neural tumors depends on the intrinsic functions and properties of the cell type, the interactions between the neoplasm and surrounding normal tissue, and regressive changes. The incidence of neural neoplasms varies with sex, location, and age of tumor onset. Although the onset of spontaneous tumor development cannot be established in routine oncogenicity studies, calculations using the time of diagnosis (day of death) have revealed significant differences in tumor biology among different rat strains. In the central nervous system, granular cell tumors (a meningioma variant), followed by glial tumors, are the most common neoplasms in rats, whereas glial cell tumors are observed most frequently in mice. Central nervous system tumors usually affect the brain rather than the spinal cord. Other than adrenal gland pheochromocytomas, the most common neoplasms of the peripheral nervous system are schwannomas. Neural tumors may develop in the central nervous system and peripheral nervous system from other cell lineages (including extraneural elements like adipose tissue and lymphocytes), but such lesions are very rare in laboratory animals.     

Neues Knochen-Band-Knochen-Transplantat aus plantaren Platten der Fußzehen und die mögliche Anwendung in der SL-Band-Rekonstruktion

Background

Various treatment options have been proposed for reconstruction of the scapholunate ligament. However, none of these methods prevent patients with scapholunate instability from developing wrist arthritis. This study was performed to investigate a new bone-ligament-bone autograft from the plantar plate of the toes for suitable reconstruction of the scapholunate interosseus ligament. The anatomical properties and the technical feasibility were investigated.

Methods

The plantar plates of the metatarso-phalangeal joints and the proximal interphalangeal joints of the 2nd–5th toes were examined in 20 cadaver feet and measurements such as length, thickness and width were recorded.

Results

The average lengths of the plantar ligaments of the proximal interphalangeal joint were 0.63 cm (D3) and 0.62 cm (D4), respectively and were therefore found to be similar to that of the scapholunate ligament. Bone-ligament-bone autografts of the plantar plates were designed and intercalated between the scaphoid and lunate bones and, contrary to all previous methods, not simply superimposed upon them.

Conclusions

It can be concluded from the data that this new graft of the proximal interphalangeal joint of the 3rd and 4th toes can be a suitable replacement for the scapholunate ligament.     

Comparison of piece‐wise linear,linear, and nonlinear atlas‐to‐patient warping techniques: Analysis of the labeling of subcortical nuclei for functional neurosurgical applications

Digital atlases are commonly used in pre‐operative planning in functional neurosurgical procedures performed to minimize the symptoms of Parkinson's disease. These atlases can be customized to fit an individual patient's anatomy through atlas‐to‐patient warping procedures. Once fitted to pre‐operative magnetic resonance imaging (MRI) data, the customized atlas can be used to plan and navigate surgical procedures. Linear, piece‐wise linear and nonlinear registration methods have been used to customize different digital atlases with varying accuracies. Our goal was to evaluate eight different registration methods for atlas‐to‐patient customization of a new digital atlas of the basal ganglia and thalamus to demonstrate the value of nonlinear registration for automated atlas‐based subcortical target identification in functional neurosurgery. In this work, we evaluate the accuracy of two automated linear techniques, two piece‐wise linear techniques (requiring the identification of manually placed anatomical landmarks), and four different automated nonlinear atlas‐to‐patient warping techniques (where two of the four nonlinear techniques are variants of the ANIMAL algorithm). Since a gold standard of the subcortical anatomy is not available, manual segmentations of the striatum, globus pallidus, and thalamus are used to derive a silver standard for evaluation. Four different metrics, including the kappa statistic, the mean distance between the surfaces, the maximum distance between surfaces, and the total structure volume are used to compare the warping techniques. The results show that nonlinear techniques perform statistically better than linear and piece‐wise linear techniques. In addition, the results demonstrate statistically significant differences between the nonlinear techniques, with the ANIMAL algorithm yielding better results. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.     

Aortic and mitral prosthetic valve replacement in age groups 61-65 & 66-70 years

Prosthesis choice for aortic and mitral valve replacements in patients aged 61-70 years is difficult. We evaluated prostheses in age groups 61-65 and 66-70 years. Freedom from major thromboembolism and hemorrhage was greater for bioprostheses than mechanical prostheses in both age groups after aortic valve replacement, but only in the younger age group after mitral valve replacement. Freedom from valve-related re-operation was greater after mitral valve replacement with mechanical prostheses in both age groups, but no difference after aortic valve replacement. Valve type was predictive of major thromboembolism and hemorrhage, except in older patients undergoing mitral valve replacement. Bioprostheses are favored for aortic valve replacement in both age groups, but the risk of re-operation with a bioprosthesis in the mitral position in patients aged 61-65 years favors a mechanical prosthesis. Prosthesis choice is less definite in those aged 66-70 years.     

Advances in the analysis of hepatitis C virus specific T cell responses

There is a growing consensus that cellular immune responses are associated with the clinical outcome of hepatitis C virus infection (HCV). The development of Tetramer staining, ELISpot, flow cytometry and epitope mapping technologies make it possible to enumerate, phenotype and assess the proliferation and function of HCV specific T cells; as well as map and predict T cell epitopes and track the evolution of T cell epitopes. Such information is essential for the development of effective therapeutic and prophylactic HCV vaccines. This article summarizes the technical advances relevant to HCV specific T cell responses.     

Revealing modular architecture of human brain structural networks by using cortical thickness from MRI

Modularity, presumably shaped by evolutionary constraints, underlies the functionality of most complex networks ranged from social to biological networks. However, it remains largely unknown in human cortical networks. In a previous study, we demonstrated a network of correlations of cortical thickness among specific cortical areas and speculated that these correlations reflected an underlying structural connectivity among those brain regions. Here, we further investigated the intrinsic modular architecture of the human brain network derived from cortical thickness measurement. Modules were defined as groups of cortical regions that are connected morphologically to achieve the maximum network modularity. We show that the human cortical network is organized into 6 topological modules that closely overlap known functional domains such as auditory/language, strategic/executive, sensorimotor, visual, and mnemonic processing. The identified structure-based modular architecture may provide new insights into the functionality of cortical regions and connections between structural brain modules. This study provides the first report of modular architecture of the structural network in the human brain using cortical thickness measurements.