Assessment of the Efficacy of Tranexamic Acid Solution 5% in the Treatment of Melasma in Patients of South Asian Descent.

Melasma is a common dermatologic condition affecting all skin types. Increasing rates of melasma warrant identification of a reliable topical treatment. In recent years, off-label tranexamic acid (TA) has emerged as a potential treatment of melasma. Although the mechanism of action remains unclear, it is thought that TA inhibits melanin synthesis by blocking the interaction between melanocytes and keratinocytes while reversing the abnormal dermal changes associated with melasma. Our study assessed the efficacy of TA solution 5% for the treatment of melasma in patients with darker skin types.

Thirty-three-day storage of dithiothreitol-treated red blood cells used to eliminate daratumumab interference in serological testing.

BACKGROUND AND OBJECTIVES: Daratumumab binds CD38 on red blood cells causing interference with indirect antiglobulin tests. Dithiothreitol is used to eliminate interference allowing detection of alloantibodies. Haemolysis is observed during storage of dithiothreitol-treated antibody identification panel cells. The objective of this study was to develop a modified method for dithiothreitol treatment to reduce the haemolysis during 33 days of storage and still be able to eliminate daratumumab interference. MATERIALS AND METHODS: Panel cells were treated with various volumes of 0·2 m dithiothreitol supplied by various manufacturers. Haemolysis Index of dithiothreitol-treated and untreated panel cells was measured and compared on days 1, 15 and 33. Antibody screening tests with dithiothreitol-treated screening cells were performed on samples from 15 daratumumab-treated patients (dose 16 mg/kg) and 34 patients with known alloantibodies. Antibody identifications with dithiothreitol-treated panel cells were performed on seven additional known alloantibodies. RESULTS: Dithiothreitol treatment with a ratio of 30:25 (red blood cells:dithiothreitol) showed the same degree of haemolysis as with untreated panel cells. Daratumumab interference was eliminated in all 15 samples from daratumumab-treated patients. Twenty-six of 34 alloantibodies were detected, and all seven additional alloantibodies were identified using the modified dithiothreitol treatment. Eight alloantibodies within the Kell system were negative. No decrease in the reaction strength was observed during the 33-day storage period. CONCLUSION: The modified dithiothreitol method was able to reduce haemolysis during storage and to detect and identify alloantibodies in the presence of daratumumab.

Neuroligin-1-dependent competition regulates cortical synaptogenesis and synapse number.

Members of the neuroligin family of cell-adhesion proteins are found at excitatory and inhibitory synapses and are mutated in some familial forms of autism spectrum disorders. Although they display synaptogenic properties in heterologous systems, the function of neuroligins in vivo in the regulation of synapse formation and synapse number has been difficult to establish. We found that neuroligin-1 (NL1), which is located at excitatory postsynaptic densities, regulates activity-dependent synaptogenesis and mature synapse number on cortical layer 2/3 pyramidal neurons in vivo. However, synapse number was not sensitive to absolute NL1 levels but instead depended on transcellular differences in the relative amounts of NL1. These effects were independent of the cell-autonomous regulation of NMDA-type glutamate receptors by absolute levels of NL1. Our data indicate that transcellular competitive processes govern synapse formation and number in developing cortex and that NL1 has a central function in these processes.

Anterograde or retrograde transsynaptic labeling of CNS neurons with vesicular stomatitis virus vectors.

To understand how the nervous system processes information, a map of the connections among neurons would be of great benefit. Here we describe the use of vesicular stomatitis virus (VSV) for tracing neuronal connections in vivo. We made VSV vectors that used glycoprotein (G) genes from several other viruses. The G protein from lymphocytic choriomeningitis virus endowed VSV with the ability to spread transsynaptically, specifically in an anterograde direction, whereas the rabies virus glycoprotein gave a specifically retrograde transsynaptic pattern. The use of an avian G protein fusion allowed specific targeting of cells expressing an avian receptor, which allowed a demonstration of monosynaptic anterograde tracing from defined cells. Synaptic connectivity of pairs of virally labeled cells was demonstrated by using slice cultures and electrophysiology. In vivo infections of several areas in the mouse brain led to the predicted patterns of spread for anterograde or retrograde tracers.