A comment on "A fast L_p spike alignment metric" by A. J. Dubbs, B. A. Seiler and M. O. Magnasco [arXiv:0907.3137]

Measuring the transmitted information in metric-based clustering has become something of a standard test for the performance of a spike train metric. In this comment, the recently proposed L_p Victor-Purpura metric is used to cluster spiking responses to zebra finch songs, recorded from field L of anesthetized zebra finch. It is found that for these data the L_p metrics with p>1 modestly outperform the standard, p=1, Victor-Purpura metric. It is argued that this is because for larger values of p, the metric comes closer to performing windowed coincidence detection.Comment: 9 pages, 3 figures included as late

A Case of Henoch-Schonlein Purpura Associated with Rotavirus Infection in an Elderly Asian Male and Review of the Literature.

BACKGROUND Henoch-Schönlein purpura (HSP), a small vessel vasculitis mediated by deposition of immune-complexes containing IgA in the skin, gut, and glomeruli, often presents with abdominal pain, purpuric rash in the lower extremities and buttocks, joint pain, and hematuria. The disease most commonly targets children but can affect adults who tend to have a worse prognosis. CASE REPORT We discuss a case of HSP in an elderly Chinese male who presented with severe proximal bowel inflammation, vasculitic rash, and proteinuria; he was found to have positive stool rotavirus and giardia. He improved significantly with high dose steroids. We believe rotavirus may have been a triggering event in this patient. A brief review of the literature is also presented. CONCLUSIONS This is the first case report describing a classic presentation of HSP in an adult following a rotavirus infection. HSP can cause significant morbidity and mortality in adult patients predominantly from progressive renal failure; therefore careful management and monitoring is important. GI infections seem to be a common trigger for HSP and this case report suggests that rotavirus may be part of the spectrum

Thrombotic Thrombocytopenic Purpura, Moschcowitz Syndrome

The authors present a case of a 16-year-old boy, who was referred to the hospital due to thrombocytopenia, anemia, proteinuria and hyperbilirubinemia. Based on the clinical picture and the laboratory data, thrombotic thrombocytopenic purpura (TTP) was diagnosed. The adequate therapy was immediately started. TTP is quite a rare entity. The etiology and the pathogenesis are not well defined. The authors summarize the different pathomechanisms, which may play a role in the development of TTP. Similarity to the hemolytic uremic syndrome (HUS), therapeutic possibilities, prognosis and the outcome are also discussed. The importance of the early diagnosis of TTP in childhood, and life-saving effect of the adequate treatment are emphasized

Which spike train distance is most suitable for distinguishing rate and temporal coding?

Background: It is commonly assumed in neuronal coding that repeated presentations of a stimulus to a coding neuron elicit similar responses. One common way to assess similarity are spike train distances. These can be divided into spike-resolved, such as the Victor-Purpura and the van Rossum distance, and time-resolved, e.g. the ISI-, the SPIKE- and the RI-SPIKE-distance. New Method: We use independent steady-rate Poisson processes as surrogates for spike trains with fixed rate and no timing information to address two basic questions: How does the sensitivity of the different spike train distances to temporal coding depend on the rates of the two processes and how do the distances deal with very low rates? Results: Spike-resolved distances always contain rate information even for parameters indicating time coding. This is an issue for reasonably high rates but beneficial for very low rates. In contrast, the operational range for detecting time coding of time-resolved distances is superior at normal rates, but these measures produce artefacts at very low rates. The RI-SPIKE-distance is the only measure that is sensitive to timing information only. Comparison with Existing Methods: While our results on rate-dependent expectation values for the spike-resolved distances agree with \citet{Chicharro11}, we here go one step further and specifically investigate applicability for very low rates. Conclusions: The most appropriate measure depends on the rates of the data being analysed. Accordingly, we summarize our results in one table that allows an easy selection of the preferred measure for any kind of data.Comment: 14 pages, 6 Figures, 1 Tabl

Modern concepts of the platelet in health and disease

Thesis (M.D.)--Boston Universit

How I treat thrombotic thrombocytopenic purpura and atypical haemolytic uraemic syndrome

Thrombotic thrombocytopenic purpura (TTP) and atypical haemolytic uraemic syndrome (aHUS) are acute, rare life-threatening thrombotic microangiopathies that require rapid diagnosis and treatment. They are defined by microangiopathic haemolytic anaemia and thrombocytopenia, with renal involvement primarily in aHUS and neurological and cardiological sequelae in TTP. Prompt treatment for most cases of both conditions is with plasma exchange initially and monoclonal therapy (rituximab in TTP and eculizumab in aHUS) as the mainstay of therapy. Here we discuss the diagnosis and therapy for both disorders

“Ghost tablet” husks excreted in feces in large bupropion XL overdose

Background: Extended-release medications are widely prescribed across the spectrum of medical specialties; however, there is heterogeneity in how they are formulated. Commonly, they consist of an insoluble matrix or shell from which drug elutes, which may then be observed by patients when excreted in feces. We describe the case of a patient who ingested a large amount of extended-release bupropion tablets and subsequently passed a large number of these so-called “ghost tablets” in his stool. Case Details: A 19-year-old male presented in status epilepticus following intentional overdose of an unknown substance. He had prolonged QRS and QT intervals on ECG, hypotension requiring vasopressors, and tachycardia, and progressed to cardiac arrest and respiratory failure. On hospital day 4, he passed several large bowel movements containing apparent tablets. Serum bupropion and hydroxybupropion levels performed on serum taken at time of admission were 1800 ng/mL and 4200 ng/mL, respectively. Case Discussion: “Ghost tablets,” the insoluble remnant of some extended-release dosage forms, have been previously reported to appear in patients' stool in the course of therapeutic dosing. We present the case of a considerable quantity of these ghost tablets recovered from stool following a large bupropion XL overdose. Conclusion: Healthcare providers should be aware of the potential for this phenomenon to occur in poisoned patients. It should be documented as physical evidence of overdose in addition to clinical evidence

Infection frequently triggers thrombotic microangiopathy in patients with preexisting risk factors : a single-institution experience

Thrombotic microangiopathies are rare conditions characterized by microangiopathic hemolytic anemia, microthrombi, and multiorgan insult. The disorders, which include hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, are often acute and life threatening. We report a retrospective analysis of 65 patients presenting to our institution from 1997 to 2008 with all forms of thrombotic microangiopathy. Therapeutic plasma exchange was a requirement for analysis and 65 patients were referred to our institution; 66% of patients were female and median age at presentation was 52 years. Bacterial infection was the most commonly identified etiologic factor and in the multivariate model was the only significant variable associated with survival outcome (odds ratio 5.1, 95% confidence interval, 1.2-21.7). As infection can be considered a common trigger event for thrombotic microangiopathy, patients with hepatobiliary sepsis may benefit from elective cholecystectomy. We conclude that bacterial infection frequently triggers TTP and other thrombotic microangiopathies in patients with preexisting risk factors and propose a model for the development of these syndromes