Allogenic banking of dental pulp stem cells for innovative therapeutics

Medical research in regenerative medicine and cell-based therapy has brought encouraging perspectives for the use of stem cells in clinical trials. Multiple types of stem cells, from progenitors to pluripotent stem cells, have been investigated. Among these, dental pulp stem cells (DPSCs) are mesenchymal multipotent cells coming from the dental pulp, which is the soft tissue within teeth. They represent an interesting adult stem cell source because they are recovered in large amount in dental pulps with non-invasive techniques compared to other adult stem cell sources. DPSCs can be obtained from discarded teeth, especially wisdom teeth extracted for orthodontic reasons. To shift from promising preclinical results to therapeutic applications to human, DPSCs must be prepared in clinical grade lots and transformed into advanced therapy medicinal products (ATMP). As the production of patient-specific stem cells is costly and time-consuming, allogenic biobanking of clinical grade human leukocyte antigen (HLA)-typed DPSC lines provides efficient innovative therapeutic products. DPSC biobanks represent industrial and therapeutic innovations by using discarded biological tissues (dental pulps) as a source of mesenchymal stem cells to produce and store, in good manufacturing practice (GMP) conditions, DPSC therapeutic batches. In this review, we discuss about the challenges to transfer biological samples from a donor to HLA-typed DPSC therapeutic lots, following regulations, GMP guidelines and ethical principles. We also present some clinical applications, for which there is no efficient therapeutics so far, but that DPSCs-based ATMP could potentially treat.     

Relationship between Fungal Colonisation of the Respiratory Tract in Lung Transplant Recipients and Fungal Contamination of the Hospital Environment

Background

Aspergillus colonisation is frequently reported after lung transplantation. The question of whether aspergillus colonisation is related to the hospital environment is crucial to prevention.

Method

To elucidate this question, a prospective study of aspergillus colonisation after lung transplantation, along with a mycological survey of the patient environment, was performed.

Results

Forty-four consecutive patients were included from the day of lung transplantation and then examined weekly for aspergillus colonisation until hospital discharge. Environmental fungal contamination of each patient was followed weekly via air and surface sampling. Twelve patients (27%) had transient aspergillus colonisation, occurring 1–13 weeks after lung transplantation, without associated manifestation of aspergillosis. Responsible Aspergillus species were A. fumigatus (6), A. niger (3), A. sydowii (1), A. calidoustus (1) and Aspergillus sp. (1). In the environment, contamination by Penicillium and Aspergillus was predominant. Multivariate analysis showed a significant association between occurrence of aspergillus colonisation and fungal contamination of the patient’s room, either by Aspergillus spp. in the air or by A.fumigatus on the floor. Related clinical and environmental isolates were genotyped in 9 cases of aspergillus colonisation. For A. fumigatus (4 cases), two identical microsatellite profiles were found between clinical and environmental isolates collected on distant dates or locations. For other Aspergillus species, isolates were different in 2 cases; in 3 cases of aspergillus colonisation by A. sydowii, A. niger and A. calidoustus, similarity between clinical and environmental internal transcribed spacer and tubulin sequences was >99%.

Conclusion

Taken together, these results support the hypothesis of environmental risk of hospital acquisition of aspergillus colonisation in lung transplant recipients.     

Combining the Estimated Date of HIV Infection with a Phylogenetic Cluster Study to Better Understand HIV Spread: Application in a Paris Neighbourhood

Objectives

To relate socio-demographic and virological information to phylogenetic clustering in HIV infected patients in a limited geographical area and to evaluate the role of recently infected individuals in the spread of HIV.

Methods

HIV-1 pol sequences from newly diagnosed and treatment-naive patients receiving follow-up between 2008 and 2011 by physicians belonging to a health network in Paris were used to build a phylogenetic tree using neighbour-joining analysis. Time since infection was estimated by immunoassay to define recently infected patients (very early infected presenters, VEP). Data on socio-demographic, clinical and biological features in clustered and non-clustered patients were compared. Chains of infection structure was also analysed.

Results

547 patients were included, 49 chains of infection containing 108 (20%) patients were identified by phylogenetic analysis. analysis. Eighty individuals formed pairs and 28 individuals were belonging to larger clusters. The median time between two successive HIV diagnoses in the same chain of infection was 248 days [CI = 176–320]. 34.7% of individuals were considered as VEP, and 27% of them were included in chains of infection. Multivariable analysis showed that belonging to a cluster was more frequent in VEP and those under 30 years old (OR: 3.65, 95 CI 1.49–8.95, p = 0.005 and OR: 2.42, 95% CI 1.05–5.85, p = 0.04 respectively). The prevalence of drug resistance was not associated with belonging to a pair or a cluster. Within chains, VEP were not grouped together more than chance predicted (p = 0.97).

Conclusions

Most newly diagnosed patients did not belong to a chain of infection, confirming the importance of undiagnosed or untreated HIV infected individuals in transmission. Furthermore, clusters involving both recently infected individuals and longstanding infected individuals support a substantial role in transmission of the latter before diagnosis.     

A Simple Dynamic Model of Respiratory Pump

To study the interaction of forces that produce chest wall motion, we propose a model based on the lever system of Hillman and Finucane (J Appl Physiol 63(3):951–961, 1987) and introduce some dynamic properties of the respiratory system. The passive elements (rib cage and abdomen) are considered as elastic compartments linked to the open air via a resistive tube, an image of airways. The respiratory muscles (active) force is applied to both compartments. Parameters of the model are identified in using experimental data of airflow signal measured by pneumotachography and rib cage and abdomen signals measured by respiratory inductive plethysmography on eleven healthy volunteers in five conditions: at rest and with four level of added loads. A breath by breath analysis showed, whatever the individual and the condition are, that there are several breaths on which the airflow simulated by our model is well fitted to the airflow measured by pneumotachography as estimated by a determination coefficient R ² ≥ 0.70. This very simple model may well represent the behaviour of the chest wall and thus may be useful to interpret the relative motion of rib cage and abdomen during quiet breathing.     

The production of fluorescent transgenic trout to study <Emphasis Type="Italic">in vitro</Emphasis> myogenic cell differentiation

Background  

Fish skeletal muscle growth involves the activation of a resident myogenic stem cell population, referred to as satellite cells, that can fuse with pre-existing muscle fibers or among themselves to generate a new fiber. In order to monitor the regulation of myogenic cell differentiation and fusion by various extrinsic factors, we generated transgenic trout (Oncorhynchus mykiss) carrying a construct containing the green fluorescent protein reporter gene driven by a fast myosin light chain 2 (MlC2f) promoter, and cultivated genetically modified myogenic cells derived from these fish.     

Evaluation of two library-independent microbial source tracking methods to identify sources of fecal contamination in French estuaries

In order to identify the origin of the fecal contamination observed in French estuaries, two library-independent microbial source tracking (MST) methods were selected: (i) Bacteroidales host-specific 16S rRNA gene markers and (ii) F-specific RNA bacteriophage genotyping. The specificity of the Bacteroidales markers was evaluated on human and animal (bovine, pig, sheep, and bird) feces. Two human-specific markers (HF183 and HF134), one ruminant-specific marker (CF193'), and one pig-specific marker (PF163) showed a high level of specificity (>90%). However, the data suggest that the proposed ruminant-specific CF128 marker would be better described as an animal marker, as it was observed in all bovine and sheep feces and 96% of pig feces. F RNA bacteriophages were detected in only 21% of individual fecal samples tested, in 60% of pig slurries, but in all sewage samples. Most detected F RNA bacteriophages were from genotypes II and III in sewage samples and from genotypes I and IV in bovine, pig, and bird feces and from pig slurries. Both MST methods were applied to 28 water samples collected from three watersheds at different times. Classification of water samples as subject to human, animal, or mixed fecal contamination was more frequent when using Bacteroidales markers (82.1% of water samples) than by bacteriophage genotyping (50%). The ability to classify a water sample increased with increasing Escherichia coli or enterococcus concentration. For the samples that could be classified by bacteriophage genotyping, 78% agreed with the classification obtained from Bacteroidales markers.     

Earliest Triassic microbialites in the South China block and other areas: controls on their growth and distribution

Earliest Triassic microbialites (ETMs) and inorganic carbonate crystal fans formed after the end-Permian mass extinction (ca. 251.4 Ma) within the basal Triassic Hindeodus parvus conodont zone. ETMs are distinguished from rarer, and more regional, subsequent Triassic microbialites. Large differences in ETMs between northern and southern areas of the South China block suggest geographic provinces, and ETMs are most abundant throughout the equatorial Tethys Ocean with further geographic variation. ETMs occur in shallow-marine shelves in a superanoxic stratified ocean and form the only widespread Phanerozoic microbialites with structures similar to those of the Cambro-Ordovician, and briefly after the latest Ordovician, Late Silurian and Late Devonian extinctions. ETMs disappeared long before the mid-Triassic biotic recovery, but it is not clear why, if they are interpreted as disaster taxa. In general, ETM occurrence suggests that microbially mediated calcification occurred where upwelled carbonate-rich anoxic waters mixed with warm aerated surface waters, forming regional dysoxia, so that extreme carbonate supersaturation and dysoxic conditions were both required for their growth. Long-term oceanic and atmospheric changes may have contributed to a trigger for ETM formation. In equatorial western Pangea, the earliest microbialites are late Early Triassic, but it is possible that ETMs could exist in western Pangea, if well-preserved earliest Triassic facies are discovered in future work.     

Hepatitis B virus subviral envelope particle morphogenesis and intracellular trafficking

Hepatitis B virus (HBV) is unusual in that its surface proteins (small [S], medium, and large [L]) are not only incorporated into the virion envelope but they also bud into empty subviral particles in great excess over virions. The morphogenesis of these subviral envelope particles remains unclear, but the S protein is essential and sufficient for budding. We show here that, in contrast to the presumed model, the HBV subviral particle formed by the S protein self-assembles into branched filaments in the lumen of the endoplasmic reticulum (ER). These long filaments are then folded and bridged for packing into crystal-like structures, which are then transported by ER-derived vesicles to the ER-Golgi intermediate compartment (ERGIC). Within the ERGIC, they are unpacked and relaxed, and their size and shape probably limits further progression through the secretory pathway. Such progression requires their conversion into spherical particles, which occurred spontaneously during the purification of these filaments by affinity chromatography. Small branched filaments are also formed by the L protein in the ER lumen, but these filaments are not packed into transport vesicles. They are transported less efficiently to the ERGIC, potentially accounting for the retention of the L protein within cells. These findings shed light on an important step in the HBV infectious cycle, as the intracellular accumulation of HBV subviral filaments may be directly linked to viral pathogenesis.     

Marking hard-shelled gastropods: tag loss, impact on life-history traits, and perspectives in biology

Abstract. Individual marking has long been used in many fields of biology. However, capture–mark–recapture (CMR) studies are not evenly distributed among taxonomic groups, with most studies focusing on vertebrates. For example, a limited number of studies have been conducted in gastropods, in sharp contrast to their important role as biological models or exploited natural resources. The lack of standard, validated marking techniques certainly contributes to the limited use of CMR. In this article, we evaluate two fundamental requirements for a marking technique to be suitable, i.e., tag loss (two experiments) and impact on life-history traits (survival, growth, and fecundity, in three experiments). Five marking techniques for hard-shelled gastropods were tested in the freshwater snail Physa acuta (Pulmonata). The tag-loss rate per month was lower for glued plastic marks (0.01) than for paint marks (0.03–0.07), and the tag-loss rate varied among colors (gouache paint). Under laboratory conditions, the life-history traits were not significantly affected by marking. We thus recommend using glued plastic marks for long-term studies, and paint marks for mass marking, with double marking to account for tag-loss rate. Based on an extensive literature survey, we also review current CMR practices in gastropod studies and suggest general improvements that would prove useful in both this group and invertebrates in general.