Frequency and Significance of HIV Infection among Patients Diagnosed with Thrombotic Thrombocytopenic Purpura

Background. Case series of patients with a diagnosis of thrombotic thrombocytopenic purpura (TTP) have reported different frequencies of human immunodeficiency virus (HIV) infection; some series suggest that HIV infection may cause TTP. Methods. We systematically reviewed all reports of HIV infection in case series of patients with TTP. We analyzed data from the Oklahoma TTP-HUS (hemolytic uremic syndrome) Registry, an inception cohort of 362 consecutive patients, for 1989-2007. Results. Nineteen case series reported the occurrence of HIV infection at the time of diagnosis of TTP in 0%-83% of patients; individual patient data were rarely described. The Oklahoma TTP-HUS Registry determined the HIV status at the time of diagnosis of TTP in 351 (97%) of 362 patients. HIV infection was documented in 6 (1.84%; 95% CI, 0.68%-4.01%) of 326 adult patients (age, 26-51 years); follow-up data were complete for all 6 patients. The period prevalence of HIV infection among all adults in the Oklahoma TTP-HUS Registry region for 1989-2007 was 0.30%. One patient had typical features of TTP with 5 relapses. Five patients had single episodes; in 4, the clinical features that had initially suggested the diagnosis of TTP were subsequently attributed to malignant hypertension (in 3 patients) and disseminated Kaposi sarcoma (in 1 patient). Conclusions. HIV infection, similar to other inflammatory conditions, may trigger acute episodes of TTP in susceptible patients. More commonly, acquired immunodeficiency syndrome-related disorders may mimic the clinical features of TTP. If the diagnosis of TTP is suggested in a patient with HIV infection, there should be careful evaluation for alternative diagnoses and cautious consideration of plasma exchange, the required treatment for TT

Standardized Management Protocol in Severe Postpartum Hemorrhage: A Single-Center Study.

Severe postpartum hemorrhage (sPPH) is an obstetric emergency that needs prompt and effective therapy to reduce the risk of complications. In this study, women who developed sPPH (study cohort, n = 27) were treated according to a standardized management protocol prescribing sequential administration of uterotonic drugs, crystalloids, tranexamic acid, labile blood products, low-dose fibrinogen, and recombinant activated factor VII (rFVIIa). This group was compared to patients treated with different strategies during 2 preceding periods: an in-house guideline regulating the administration of rFVIIa (historical cohort 1, n = 20) and no specific guideline (historical cohort 2, n = 27). The management protocol was used over 33 months. The study cohort had a lower estimated blood loss ( P = .004) and required less red blood cell concentrates ( P = .007), fresh frozen plasma units ( P = .004), and platelet concentrates ( P = .020) compared to historical cohort 1 and historical cohort 2, respectively. The necessity of emergency postpartum hysterectomy was lower in the study group ( P = .012). In conclusion, in patients with sPPH treated with this standardized management protocol, we observed a decreased requirement of labile blood products and lower need to proceed to emergency postpartum hysterectomy

Consensus on the standardization of terminology in thrombotic thrombocytopenic purpura and related thrombotic microangiopathies.

BACKGROUND Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are two important acute conditions to diagnose. Thrombotic Microangiopathy is a broad pathophysiological process that leads to microangiopathic hemolytic anemia, thrombocytopenia and involves capillary and small vessel platelet aggregates. The most common cause being disseminated intravascular coagulation (DIC), which may be differentiated by abnormal coagulation. Clinically, a number of conditions present with microangiopathic hemolytic anemia and thrombocytopenia (MAHAT), including cancer, infection, transplantation, drugs, autoimmune disease and pre-eclampsia and HELLP (Hemolysis, Elevated Liver enzymes, Low Platelet count) syndrome in pregnancy. Despite overlapping clinical presentations, TTP and HUS have distinct pathophysiology and treatment pathways. OBJECTIVES Presented is a consensus document from an international working group on TTP and associated TMAs (thrombotic microangiopathies). METHODS The international working group has proposed definitions and terminology based on published information and consensus based recommendations. CONCLUSION The consensus aims to aid clinical decisions but also future studies and trials, utilizing standardized definitions. It presents classification of the causes of TMA, and criteria for clinical response, remission and relapse of congenital and immune mediated TTP. This article is protected by copyright. All rights reserved

Using metallic noncontact atomic force microscope tips for imaging insulators and polar molecules: tip characterization and imaging mechanisms

We demonstrate that using metallic tips for noncontact atomic force microscopy (NC-AFM) imaging at relatively large (>0.5 nm) tip-surface separations provides a reliable method for studying molecules on insulating surfaces with chemical resolution and greatly reduces the complexity of interpreting experimental data. The experimental NC-AFM imaging and theoretical simulations were carried out for the NiO(001) surface as well as adsorbed CO and Co-Salen molecules using Cr-coated Si tips. The experimental results and density functional theory calculations confirm that metallic tips possess a permanent electric dipole moment with its positive end oriented toward the sample. By analyzing the experimental data, we could directly determine the dipole moment of the Cr-coated tip. A model representing the metallic tip as a point dipole is described and shown to produce NC-AFM images of individual CO molecules adsorbed onto NiO(001) in good quantitative agreement with experimental results. Finally, we discuss methods for characterizing the structure of metal-coated tips and the application of these tips to imaging dipoles of large adsorbed molecules. © 2014 American Chemical Society

The great screen anomaly—a new frontier in product discovery through functional metagenomics

Functional metagenomics, the study of the collective genome of a microbial community by expressing it in a foreign host, is an emerging field in biotechnology. Over the past years, the possibility of novel product discovery through metagenomics has developed rapidly. Thus, metagenomics has been heralded as a promising mining strategy of resources for the biotechnological and pharmaceutical industry. However, in spite of innovative work in the field of functional genomics in recent years, yields from function-based metagenomics studies still fall short of producing significant amounts of new products that are valuable for biotechnological processes. Thus, a new set of strategies is required with respect to fostering gene expression in comparison to the traditional work. These new strategies should address a major issue, that is, how to successfully express a set of unknown genes of unknown origin in a foreign host in high throughput. This article is an opinionating review of functional metagenomic screening of natural microbial communities, with a focus on the optimization of new product discovery. It first summarizes current major bottlenecks in functional metagenomics and then provides an overview of the general metagenomic assessment strategies, with a focus on the challenges that are met in the screening for, and selection of, target genes in metagenomic libraries. To identify possible screening limitations, strategies to achieve optimal gene expression are reviewed, examining the molecular events all the way from the transcription level through to the secretion of the target gene product

Unambiguous determination of the adsorption geometry of a metal--organic complex on a bulk insulator.

Individual molecules of Co-Salen, a small chiral paramagnetic metal--organic Schiff base complex, were deposited on NaCl(001) and subsequently imaged with noncontact atomic force microscopy employing Cr coated tips in a cryogenic ultrahigh vacuum environment. Images were obtained in which both the position and orientation of the adsorbed molecules and the atomic structure of the surface are resolved simultaneously, enabling the determination of the exact adsorption site. Density functional theory calculations were used to identify the ionic sublattice resolved with the Cr tip and also to confirm the adsorption site and orientation of the molecule on the surface. These calculations show that the central Co atom of the molecule physisorbs on top of a Cl ion and is aligned along 110-directions in its lowest energy configuration. In addition, a local energy minimum exists along 100-directions. Due to the chirality of the molecule, two mirror symmetric configurations rotated by approximately +/-5 degrees away from these directions are energetically equivalent. The resulting 16 low energy configurations are observed in the experimental images

Evaluation of a Platelet Function Analyser (PFA-100) in patients with a bleeding tendency

To investigate pre-analytical variables and the diagnostic performance of the platelet function analyser (PFA-100), a new device to test primary haemostasis in vitro by simulating platelet adhesion and aggregation under high shear stress. Venous whole citrated blood is aspirated through a capillary towards an aperture of a collagen coated membrane containing either adenosine diphosphate (ADP) or epinephrine (EPI). The time needed for occluding this aperture by plug formation is called closure time (CT) and was assessed in 70 healthy subjects and 43 patients with a suspected mild bleeding disorder. The reference range for the PFA-100 was found to be 82-159 s for EPI-CT and 62.5-120.5 s for ADP-CT. Duplicate analyses revealed a mean coefficient of variations of 7.1% (EPI-CT) and 5.7% (ADP-CT). The EPI- and ADP-CT of blood samples collected in the evening were significantly longer (p = 0.002 and p = 0.004, respectively) than the CT of blood samples collected in the morning. Acetylsalicylic acid(100 mg, 300 mg or 500 mg) administered as a single dose or daily on 10 consecutive days resulted in a prolongation of the EPI-CT, whereas the ADP-CT was not affected. EPI-CT was more sensitive in detecting acetylsalicylic acid (ASA) ingestion than was the bleeding time (BT). Sensitivity and specificity of the PFA-100 to detect von Willebrand disease (vWD) were comparable to the results obtained with the BT. The PFA-100 represents a simple and easy to use test for investigation of primary haemostasis. Limitations of the system are: special citrated whole blood has to be proceeded within 0.5 to 4 h after sampling, duplicate measurements are necessary, and the results differ between blood sampled in the morning or in the afternoon. The data indicate that the test is sensitive to ASA intake and vWD. Its use is preferable to BT determination, because it is less invasive and more sensitive to abnormalities of primary haemostasi

Unambiguous determination of the adsorption geometry of a metal--organic complex on a bulk insulator.

Individual molecules of Co-Salen, a small chiral paramagnetic metal--organic Schiff base complex, were deposited on NaCl(001) and subsequently imaged with noncontact atomic force microscopy employing Cr coated tips in a cryogenic ultrahigh vacuum environment. Images were obtained in which both the position and orientation of the adsorbed molecules and the atomic structure of the surface are resolved simultaneously, enabling the determination of the exact adsorption site. Density functional theory calculations were used to identify the ionic sublattice resolved with the Cr tip and also to confirm the adsorption site and orientation of the molecule on the surface. These calculations show that the central Co atom of the molecule physisorbs on top of a Cl ion and is aligned along 110-directions in its lowest energy configuration. In addition, a local energy minimum exists along 100-directions. Due to the chirality of the molecule, two mirror symmetric configurations rotated by approximately +/-5 degrees away from these directions are energetically equivalent. The resulting 16 low energy configurations are observed in the experimental images