Tulane University

About: Tulane University is a education organization based out in New Orleans, Louisiana, United States. It is known for research contribution in the topics: Population & Blood pressure. The organization has 24478 authors who have published 47205 publications receiving 1944993 citations. The organization is also known as: University of Louisiana.

Sensitive and Specific Serodiagnosis of Lyme Disease by Enzyme-Linked Immunosorbent Assay with a Peptide Based on an Immunodominant Conserved Region of Borrelia burgdorferi VlsE

Abstract: VlsE, the variable surface antigen of Borrelia burgdorferi, contains an immunodominant conserved region named IR6. In the present study, the diagnostic performance of a peptide enzyme-linked immunosorbent assay (ELISA) based on a 26-mer synthetic peptide (C6) with the IR6 sequence was explored. Sensitivity was assessed with serum samples (n = 210) collected from patients with clinically defined Lyme disease at the acute (early localized or early disseminated disease), convalescent, or late disease phase. The sensitivities for acute-, convalescent-, and late-phase specimens were 74% (29 of 39), 85 to 90% (34 of 40 to 35 of 39), and 100% (59 of 59), respectively. Serum specimens from early neuroborreliosis patients were 95% positive (19 of 20), and those from an additional group of patients with posttreatment Lyme disease syndrome yielded a sensitivity of 62% (8 of 13). To assess the specificity of the peptide ELISA, 77 serum samples from patients with other spirochetal or chronic infections, autoimmune diseases, or neurologic diseases and 99 serum specimens from hospitalized patients in an area where Lyme disease is not endemic were examined. Only two potential false positives from the hospitalized patients were found, and the overall specificity was 99% (174 of 176). Precision, which was assessed with a panel of positive and negative serum specimens arranged in blinded duplicates, was 100%. Four serum samples with very high anti-OspA antibody titers obtained from four monkeys given the OspA vaccine did not react with the C6 peptide. This simple, sensitive, specific, and precise ELISA may contribute to alleviate some of the remaining problems in Lyme disease serodiagnosis. Because of its synthetic peptide base, it will be inexpensive to manufacture. It also will be applicable to serum specimens from OspA-vaccinated subjects.

Treatment of acute patellar dislocation

Abstract: To determine the effectiveness of nonoperative and operative treatment of initial acute patellar dislocation, we reviewed the charts of 399 patients with the diagnosis of an acute dislocation, seen during a 30 year period. One hundred patients (103 knees) met the criteria for inclusion in the study. The average age of the patient at injury was 21.7 years (range, 9 to 72 years). Length of followup averaged 8 years (range, 2 to 26 years). Retrospectively, we divided the patients into two groups, according to the examination of their unaffected knee. Group I (69 knees) showed evidence on examination of congenital abnormality of the extensor mechanism in the unaffected knee, indicating a predisposition to dislocate with less significant trauma. Group II (34 knees) showed no clinically perceptible congenital predisposition to dislocate based on examination of the unaffected knee. In the nonoperatively treated knees in Group I, there was a 52% (28/54) incidence of good or excellent results. The nonoperatively treated knees in Group II had a 75% (15/20) incidence of good or excellent results. Acute dislocation occurred more frequently in males than in females. Recurrence was rarer in patients whose initial dislocation had occurred when they were over 15 years old. Contrary to recently published reports, primary acute traumatic patellar dislocations can be treated with nonoperative therapy with good or excellent results. Initial evaluation should include examination of the uninvolved knee which, if found to have signs of congenital abnormality, would indicate a worse prognosis.

Platform Ecosystems: How Developers Invert the Firm

Abstract: For a period starting in 2015, Apple, Google, and Microsoft became the most valuable companies in the world. Each was marked by an external developer ecosystem. Anecdotally, at least, developers matter. Using a formal model of code spillovers, we show how a rising number of developers can invert the firm. That is, firms will choose to innovate using open external contracts in preference to closed vertical integration. The locus of value creation moves from inside the firm to outside. Distinct from physical goods, digital goods afford firms the chance to optimize spillovers. Further, firms that pursue high risk innovations with more developers can be more profitable than firms that pursue low risk innovations with fewer developers. More developers give platform firms more chances at success. Our contribution is to show why developers might cause a shift in organizational form and to provide a theory of how platform firms optimize their own intellectual property regimes in order to maximize growth. We use stylized facts from multiple platform firms to illustrate our theory and results.

Rapid Glucocorticoid-Mediated Endocannabinoid Release and Opposing Regulation of Glutamate and γ-Aminobutyric Acid Inputs to Hypothalamic Magnocellular Neurons

Abstract: Glucocorticoids secreted in response to stress activation of the hypothalamic-pituitary-adrenal axis feed back onto the brain to rapidly suppress neuroendocrine activation, including oxytocin and vasopressin secretion. Here we show using whole-cell patch clamp recordings that glucocorticoids elicit a rapid, opposing action on synaptic glutamate and γ-aminobutyric acid (GABA) release onto magnocellular neurons of the hypothalamic supraoptic nucleus and paraventricular nucleus, suppressing glutamate release and facilitating GABA release by activating a putative membrane receptor. The glucocorticoid effect on both glutamate and GABA release was blocked by inhibiting postsynaptic G protein activity, suggesting a dependence on postsynaptic G protein signaling and the involvement of a retrograde messenger. Biochemical analysis of hypothalamic slices treated with dexamethasone revealed a glucocorticoid-induced rapid increase in the levels of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG)...