Cooperative changes in GABA, glutamate and activity levels: the missing link in cortical plasticity

Different intracortical mechanisms have been reported to contribute to the substantial topographic reorganization of the mammalian primary visual cortex in response to matching lesions in the two retinas: an immediate expansion of receptive fields followed by a gradual shift of excitability into the deprived area and finally axonal sprouting of laterally projecting neurons months after the lesion. To gain insight into the molecular mechanisms of this adult plasticity, we used immunocytochemical and bioanalytical methods to measure the glutamate and GABA neurotransmitter levels in the visual cortex of adult cats with binocular central retinal lesions. Two to four weeks after the lesions, glutamate immunoreactivity was decreased in sensory-deprived cortex as confirmed by HPLC analysis of the glutamate concentration. Within three months normal glutamate immunoreactivity was restored. In addition, the edge of the unresponsive cortex was characterized by markedly increased glutamate immunoreactivity 2-12 weeks postlesion. This glutamate immunoreactivity peak moved into the deprived area over time. These glutamate changes corresponded to decreased spontaneous and visually driven activity in unresponsive cortex and to strikingly increased neuronal activity at the border of this cortical zone. Furthermore, the previously reported decrease in glutamic acid decarboxylase immunoreactivity was found to reflect decreased GABA levels in sensory-deprived cortex. Increased glutamate concentrations and neuronal activity, and decreased GABA concentrations, may be related to changes in synaptic efficiency and could represent a mechanism underlying the retinotopic reorganization that occurs well after the immediate receptive field expansion but long before the late axonal sprouting.

Rapid identification of Mycobacteria to the species level using INNO-LiPA Mycobacteria, a reverse hybridization assay

INNO-LiPA Mycobacteria (LiPA; Innogenetics, Zwijnaarde, Belgium) is a kit for the simultaneous detection and identification of Mycobacterium species in culture and identifies the Mycobacterium tuberculosis complex, the M. avium complex (MAC), and the following Mycobacterium species: M. kansasii, M. avium, M. intracellulare, M. scrofulaceum, M. gordonae, M. xenopi, and the M. chelonae-M. abscessus complex. The assay, which targets the 16S-23S rRNA spacer region, was evaluated on 157 mycobacterial strains that had been identified by conventional techniques and PCR-restriction enzyme analysis of the hsp65 gene (PRA). Forty-seven reference strains consisting of 37 different species and 110 human clinical isolates were submitted to the test, and all were hybridized with the Mycobacterium genus probe (MYC) on the LiPA strip (100% sensitivity). Ninety-four isolates hybridized to their corresponding species- or complex-specific probes; only one isolate phenotypically identified as M. gordonae did not react with its specific probe (99.4% accuracy). Thirty-seven MAC strains were phenotypically identified to the complex level and to the species level by LiPA as M. avium (n = 18) or M. intracellulare (n = 7) or as belonging to the M. avium-M. intracellulare-M. scrofulaceum complex (n = 12). Of the last 12 strains, 10 had M. avium PRA patterns and 2 had M. intracellulare PRA patterns. Three isolates that had been identified as a single species by conventional identification were proven to be mixed cultures by the LiPA assay. The whole procedure can be performed in 1 working day, starting with the supernatant of a small amount of bacterial mass that had been treated by freezing and then boiling.

Epidemiological study of lathyrism in northwestern districts of Bangladesh

Two northwestern districts of Bangladesh with a population of 629,752 were surveyed from June 1991 to March 1993 to detect and follow up lathyrism patients. Out of 2,567 neurological patients, 882 were diagnosed as having lathyrism, giving a prevalence rate of 14.0/10,000. This prevalence was higher among young males: only 12.9% of the patients were female, and only 19.3% of the patients were over 30 years of age at onset of the disease. The average family size was 4.6 members. In the surveyed area, 730 families were evaluated: 622 families had only 1 affected member, and 108 families had 2-8 affected members. Most of the patients were working, while only 4% were not. The majority of the patients had a very low intake of animal protein. A few cases of human T-lymphotropic virus infection and osteolathyrism were found during this study.

Biological and Physicochemical Characterization of a Serum-and Xeno-Free Chemically Defined Cryopreservation Procedure for Adult Human Progenitor Cells

While therapeutic cell transplantations using progenitor cells are increasingly evolving towards phase I and II clinical trials and chemically defined cell culture is established, standardization in biobanking is still in the stage of infancy. In this study, the EU FP6-funded CRYSTAL (CRYo-banking of Stem cells for human Therapeutic AppLication) consortium aimed to validate novel Standard Operating Procedures (SOPs) to perform and validate xeno-free and chemically defined cryopreservation of human progenitor cells and to reduce the amount of the potentially toxic cryoprotectant additive (CPA) dimethyl sulfoxide (DMSO). To achieve this goal, three human adult progenitor and stem cell populations—umbilical cord blood (UCB)-derived erythroid cells (UCB-ECs), UCB-derived endothelial colony forming cells (UCB-ECFCs), and adipose tissue (AT)-derived mesenchymal stromal cells (AT-MSCs)—were cryopreserved in chemically defined medium supplemented with 10% or 5% DMSO. Cell recovery, cell repopulation, and functionality were evaluated postthaw in comparison to cryopreservation in standard fetal bovine serum (FBS)-containing freezing medium. Even with a reduction of the DMSO CPA to 5%, postthaw cell count and viability assays indicated no overall significant difference versus standard cryomedium. Additionally, to compare cellular morphology/membrane integrity and ice crystal formation during cryopreservation, multiphoton laser-scanning cryomicroscopy (cryo-MPLSM) and scanning electron microscopy (SEM) were used. Neither cryo-MPLSM nor SEM indicated differences in membrane integrity for the tested cell populations under various conditions. Moreover, no influence was observed on functional properties of the cells following cryopreservation in chemically defined freezing medium, except for UCB-ECs, which showed a significantly reduced differentiation capacity after cryopreservation in chemically defined medium supplemented with 5% DMSO. In summary, these results demonstrate the feasibility and robustness of standardized xeno-free cryopreservation of different human progenitor cells and encourage their use even more in the field of tissue-engineering and regenerative medicine.

Cryopreservation of hematopoietic stem and progenitor cells amplified ex vivo from cord blood CD34+ cells

BACKGROUND

Our ex vivo expansion procedure starting from cord blood (CB) CD34+ cells enabled expansion of committed progenitors (CPs) without a negative impact on hematopoietic stem cells (HSCs) exhibiting both short- and long-term repopulating capacity. Upgraded to clinical scale (Macopharma HP01 in the presence of stem cell factor, FLT3-L [100 ng/mL each], granulocyte-colony-stimulating factor [10 ng/mL], and thrombopoietin [20 ng/mL]), it is being used for an ongoing clinical trial (adult allogeneic context) yielding promising preliminary results. Transplantation of ex vivo expanded CB cells is becoming a reality, while the issue of expanded cells' cryopreservation emerges as an option that allows the conservation of the product for transportation and future use. Here, we investigated whether it is possible to maintain the functional HSC and CP properties after freezing and thawing of expanded cells.

STUDY DESIGN AND METHODS

We compared cryopreservation efficiency of the ex vivo expanded CB cells using the standard protocol (freezing solution human serum albumin (HSA)-dimethyl sulfoxide [DMSO]) with the newly designed protocol based on an enriched freezing solution (HP01-DMSO) with respect to the viability index, number of CD34+ and total cells, and recovery of CPs (colony-forming units) and HSCs (NOG/Scid/gamma-null mice engraftment).

RESULTS

Cryopreservation and thawing of expanded CB cells using the "standard" procedure (HSA-DMSO) reduced recovery of the CPs (40%) and HSCs (drastically decreasing engraftment capacity). HP01-based protocol resulted in improvement of preservation of both CPs (>60%) and HSCs (nonaltered engraftment capacities).

CONCLUSION

Functional maintenance of the expanded graft by cryopreservation is feasible in conditions compatible with human cell therapy requirements.

Hybridization model for Rhipicephalus appendiculatus and R. zambeziensis by glucose-P-isomerase isoenzymes

Hybrids between Rhipicephalus appendiculatus and R. zambeziensis were reared and glucose-phosphate-isomerase isoenzymes were resolved by agarose electrophoresis. By phenotyping hybrids in F1 and F2 generations autosomal transmission of 2 GPI genes was demonstrated. Identification of a hybrid phenotype provides a method for identifying hybrids in field collections.

Study of HTLV-I antibodies in CSF and serum of neurolathyrism patients in Bangladesh

Neurolathyrism is a form of human spastic paraparesis related to the overconsumption of the legume Lathyrus sativus or grass pea (Khesari in Bangladesh) containing the neurotoxin 3-N-oxalyl-2,3-diaminopropanoic acid (beta-ODAP). The clinical symptoms of neurolathyrism are similar to those of Tropical Spastic Paraparesis. In order to eliminate the proposed causative agent of TSP (HTLV-I) as a potential cause of the symptoms ascribed to neurolathyrism, a total of 444 diagnosed lathyrism patients were screened for HTLV-I antibodies. 50 CSF and 394 serum samples were collected from male (415) and female (29) patients. Only 4 serum samples were found sero-positive for HTLV-I. This agrees with the assumption that overconsumption of beta-ODAP containing Lathyrus seeds, and not HTLV infection, is the causative agent for neurolathyrism.

No correlation between remifentanil blood, cerebrospinal fluid and cerebral extracellular fluid levels and TCI prediction: a pharmacokinetic study

BACKGROUND

The aims of this paper were to elucidate the difference in concentration among remifentanil blood, cerebrospinal fluid and cerebral extracellular fluid levels, and to verify the presumable existence of a correlation between arterial and cerebral remifentanil. We used brain microdialysis to shed light on this aspect of the pharmacokinetic and to correlate these findings with Minto's model.

METHODS

The study population was formed by 9 patients scheduled for elective intracranial surgery for cerebral supratentorial neoplasia. All patients received general anaesthetic; 100 microliters of dialysate were collected. Furthermore, arterial blood samples of 3 mL each were collected, respectively one at the beginning and one at the end of the sampling period. We determined the concentration of remifentanil and its main metabolite, remifentanil acid, in the blood and in the brain. The predictive performance of the Minto pharmacokinetic parameter set was evaluated by examining the performance error.

RESULTS

The mean Performance Error was -45.13% (min -21.80, max -88.75) for the first series of arterial samples, -38.29% (min -6.57, max -79.17) for the second one and 67.73% (min 7, max -93.12) for the extra cellular fluid sample. The concentration of remifentanil set pumps was correlated with blood concentration for both series of samples. Neither the set concentration, nor the arterial samples were correlated with extra cellular fluid values.

CONCLUSION

There was a wide interindividual variability with regard both to blood and cerebral remifentanil concentration. Moreover, the ratio between arterial blood and cerebral remifentanil was not consistent among our patients in spite of a stable infusion rate of remifentanil; at the end we found a trend of over prediction in the ratio between the various compartments examined.

Mechanobiological Strategies to Enhance Ovine (Ovis aries) Adipose-Derived Stem Cells Tendon Plasticity for Regenerative Medicine and Tissue Engineering Applications

Adipose-derived stem cells (ADSCs) hold promise for tendon repair, even if their tenogenic plasticity and underlying mechanisms remain only partially understood, particularly in cells derived from the ovine animal model. This study aimed to characterize oADSCs during in vitro expansion to validate their phenotypic properties pre-transplantation. Moreover, their tenogenic potential was assessed using two in vitro-validated approaches: (1) teno-inductive conditioned media (CM) derived from a co-culture between ovine amniotic stem cells and fetal tendon explants, and (2) short- (48 h) and long-term (14 days) seeding on highly aligned PLGA (ha-PLGA) electrospun scaffold. Our findings indicate that oADSCs can be expanded without senescence and can maintain the expression of stemness (Sox2, Oct4, Nanog) and mesenchymal (CD29, CD166, CD44, CD90) markers while remaining negative for hematopoietic (CD31, CD45) and MHC-II antigens. Of note, oADSCs' tendon differentiation potential greatly depended on the in vitro strategy. oADSCs exposed to CM significantly upregulated tendon-related genes (COL1, TNMD, THBS4) but failed to accumulate TNMD protein at 14 days of culture. Conversely, oADSCs seeded on ha-PLGA fleeces quickly upregulated the tendon-related genes (48 h) and in 14 days accumulated high levels of the TNMD protein into the cytoplasm of ADSCs, displaying a tenocyte-like morphology. This mechano-sensing cellular response involved a complete SOX9 downregulation accompanied by YAP activation, highlighting the efficacy of biophysical stimuli in promoting tenogenic differentiation. These findings underscore oADSCs' long-term self-renewal and tendon differentiative potential, thus opening their use in a preclinical setting to develop innovative stem cell-based and tissue engineering protocols for tendon regeneration, applied to the veterinary field.