Evaluation of the Stability of Bacteriophages in Different Solutions Suitable for the Production of Magistral Preparations in Belgium.

In Belgium, the incorporation of phages into magistral preparations for human application has been permitted since 2018. The stability of such preparations is of high importance to guarantee quality and efficacy throughout treatments. We evaluated the ability to preserve infectivity of four different phages active against three different bacterial species in five different buffer and infusion solutions commonly used in medicine and biotechnological manufacturing processes, at two different concentrations (9 and 7 log pfu/mL), stored at 4 °C. DPBS without Ca2+ and Mg2+ was found to be the best option, compared to the other solutions. Suspensions with phage concentrations of 7 log pfu/mL were unsuited as their activity dropped below the effective therapeutic dose (6-9 log pfu/mL), even after one week of storage at 4 °C. Strong variability between phages was observed, with Acinetobacter baumannii phage Acibel004 being stable in four out of five different solutions. We also studied the long term storage of lyophilized staphylococcal phage ISP, and found that the titer could be preserved during a period of almost 8 years when sucrose and trehalose were used as stabilizers. After rehydration of the lyophilized ISP phage in saline, the phage solutions remained stable at 4 °C during a period of 126 days.

Rapid and accurate identification of isolates of Candida species by melting peak and melting curve analysis of the internally transcribed spacer region 2 fragment (ITS2-MCA).

Rapid identification of clinically important yeasts can facilitate the initiation of anti-fungal therapy, since susceptibility is largely species-dependent. We evaluated melting peak and melting curve analysis of the internally transcribed spacer region 2 fragment (ITS2-MCA) as an identification tool for distinguishing between 16 Candida spp., i.e. Candida albicans, Candida bracarensis, Candida dubliniensis, Candida famata, Candida glabrata, Candida guilliermondii, Candida inconspicua, Candida kefyr, Candida krusei, Candida lipolytica, Candida lusitaniae, Candida nivariensis, Candida norvegensis, Candida parapsilosis, Candida tropicalis and Candida sojae, and Saccharomyces cerevisiae and one species pair, i.e. Candida metapsilosis/Candida orthopsilosis. Starting from a cultured isolate, ITS2-MCA led to differentiation of these species within 6 h. According to our findings, ITS2-MCA offers a simple, rapid and cost-effective method for identification of cultured isolates of the clinically most relevant and prevalent Candida species. Further studies will be necessary to evaluate how it performs on mixed samples and clinical samples.

Loss-of-function mutations in LEMD3 result in osteopoikilosis, Buschke-Ollendorff syndrome and melorheostosis.

Osteopoikilosis, Buschke-Ollendorff syndrome (BOS) and melorheostosis are disorders characterized by increased bone density. The occurrence of one or more of these phenotypes in the same individual or family suggests that these entities might be allelic. We collected data from three families in which affected individuals had osteopoikilosis with or without manifestations of BOS or melorheostosis. A genome-wide linkage analysis in these families, followed by the identification of a microdeletion in an unrelated individual with these diseases, allowed us to map the gene that is mutated in osteopoikilosis. All the affected individuals that we investigated were heterozygous with respect to a loss-of-function mutation in LEMD3 (also called MAN1), which encodes an inner nuclear membrane protein. A somatic mutation in the second allele of LEMD3 could not be identified in fibroblasts from affected skin of an individual with BOS and an individual with melorheostosis. XMAN1, the Xenopus laevis ortholog, antagonizes BMP signaling during embryogenesis. In this study, LEMD3 interacted with BMP and activin-TGFbeta receptor-activated Smads and antagonized both signaling pathways in human cells.

Cardiac phenotypes in chromosome 4q- syndrome with and without a deletion of the dHAND gene.

PURPOSE: Terminal deletions of chromosome 4q are commonly associated with cardiovascular malformations (CVMs). The dHAND gene (HAND2 heart and neural crest derivative express 2), a basic helix-loop-helix transcription factor expressed in the developing heart, maps to 4q33. A targeted deletion in mouse shows that dHAND plays an important role in heart development, suggesting that haploinsufficiency of in patients with 4q deletions may be causal for CVMs. The purpose of this study is to examine the possible association between dHAND haploinsufficiency with the CVMs that occur in patients with 4q terminal deletions. METHODS: Fluorescence in situ hybridization (FISH) was performed with a dHAND human genomic probe on five patients with terminal deletion at 4q33 or 4q34. RESULTS: Of the three patients with a deletion of the dHAND locus, two had CVM (both valvar pulmonic stenosis). Of the two patients without a deletion of the dHAND gene, one had a small atrial septal defect noted on autopsy. In one of the patients with breakpoint on chromosome 4 assigned to 4q34.2 by GTG-banding, FISH revealed deletion of the dHAND gene. CONCLUSION: The results suggest that cardiac phenotypes are very variable in patients with the terminal deletion of chromosome 4q and that haploinsufficiency of the dHAND is not necessarily associated with CVMs. The correct cytogenetic interpretation of terminal chromosome deletions might be augmented by FISH.