Effectiveness of a structured stimulated spontaneous safety monitoring of medicines reporting program in strengthening pharmacovigilance system in Tanzania.

Under-reporting of adverse drug events (ADEs) is a challenge facing developing countries including Tanzania. Given the high magnitude of under-reporting, it was necessary to develop and assess the effectiveness of a 'structured stimulated spontaneous safety monitoring' (SSSSM) reporting program of ADEs which aimed at strengthening pharmacovigilance system in Tanzania. A quasi-experimental design and data mining technique were used to assess the effect of intervention after the introduction of program in seven tertiary hospitals. ADEs reports were collected from a single group and compared for 18 months before (July 2017 to December, 2018) and after the program (January 2019 to June 2020). Out of 16,557 ADEs reports, 98.6% (16,332) were reported after intervention and 0.1% (23) death related to adverse drug reactions (ADRs) were reported. Reports increased from 20 to 11,637 after intervention in Dar es salaam, 49 to 316 in Kilimanjaro and 17 to 77 in Mbeya. The population-based reporting ratio per 1,000,000 inhabitants increased from 2 reports per million inhabitants in 2018 to 85 reports in 2019. The SSSSM program can increase the reporting rate of ADEs and was useful in detecting signals from all types of medicines. This was first effective developed spontaneous program to monitor medicine safety in Tanzania.

A retrospective cross-sectional study to determine chirality status of registered medicines in Tanzania.

Medicines with a stereogenic center (asymmetric carbon) are mainly present as racemates with a mixture of equal amounts of enantiomers. One enantiomer may be active while the other inactive, alternatively one may produce side-effects and even toxicity. However, there is lack of information on the chirality status (either racemates, single active enantiomer or achiral) of medicines circulated on the market particularly in African countries. We established the chirality status of registered medicines in Tanzania by conducting a retrospective cross-sectional study. Registration data for the past 15 years from 2003 to 2018 were extracted from TMDA-IMIS database to Microsoft excel for review and analysis. A total of 3,573 human medicines had valid registration. Out of which 2,150 (60%) were chiral and 1,423 (40%) achiral. Out of the chiral medicines, 1,591 (74%) and 559 (26%) were racemates and single active enantiomers, respectively. The proportion of racemates within chiral medicines was considerably higher than single enantiomer medicines. The use of racemates may cause harm to the public and may contribute to antimicrobial resistance due to potential existence of inactive and toxic enantiomers. In order to protect public health, regulatory bodies need to strengthen control of chiral medicines by conducting analysis of enantiomeric impurity.

Transition from paediatric to adult health services in Scotland for young people with cerebral palsy.

Transition from paediatric to adult health-care services has been characterized as being poorly planned and coordinated, resulting in a reduction in services and may be distressing for families. This study aimed to establish what provisions are currently available in Scotland for transition of young people with cerebral palsy and what some clinicians believe future provisions should involve. Semi-structured interviews were conducted with 13 community paediatricians (or equivalents in health boards without community paediatricians) from 12 different Scottish health boards. Interviews were audio recorded, transcribed and analysed thematically using framework analysis. Both current transition provision and the areas that the clinicians felt needed improvement varied greatly between health boards. Key areas in need of improvement were coordination and communication within health services and also between health services and educational, social services and adult health services to which young people were transitioning. Transition remains problematic and variable. For transition to be improved, further research is needed to explore the effect this variation is having on young people and their families.

Axon behaviour at Schwann cell - astrocyte boundaries: manipulation of axon signalling pathways and the neural adhesion molecule L1 can enable axons to cross.

Axon regeneration in vivo is blocked at boundaries between Schwann cells and astrocytes, such as occur at the dorsal root entry zone and around peripheral nerve or Schwann cell grafts. We have created a tissue culture model of these boundaries in Schwann cell - astrocyte monolayer co-cultures. Axon behaviour resembles that in vivo, with axons showing a strong preference for Schwann cells over astrocytes. At boundaries between the two cell types, axons growing on astrocytes cross readily onto Schwann cells, but only 15% of axons growing on Schwann cells are able to cross onto astrocytes. Treatment with chondroitinase or chlorate to reduce inhibition by proteoglycans did not change this behaviour. The neural adhesion molecule L1 is present on Schwann cells and not astrocytes, and manipulation of L1 by application of an antibody, L1-Fc in solution, or adenoviral transduction of L1 into astrocytes increased the proportion of axons able to cross onto astrocytes to 40-50%. Elevating cAMP levels increased crossing from Schwann cells onto astrocytes in live and fixed cultures, and had a co-operative effect with NT-3 but not with NGF. Inactivation of Rho with a cell-permeant form of C3 exoenzyme also increased crossing from Schwann cells to astrocytes. Our experiments indicate that the preference of axons for Schwann cells is largely mediated by the presence of L1 on Schwann cells but not astrocytes, and that manipulation of growth cone signalling pathways can allow axons to disregard boundaries between the two cell types.

The astrocyte/meningeal cell interface is a barrier to neurite outgrowth which can be overcome by manipulation of inhibitory molecules or axonal signalling pathways.

Invading meningeal cells form a barrier to axon regeneration after damage to the spinal cord and other parts of the CNS, axons stopping at the interface between meningeal cells and astrocytes. Axon behavior was examined using an in vitro model of astrocyte/meningeal cell interfaces, created by plating aggregates of astrocytes and meningeal cells onto coverslips. At these interfaces growth of dorsal root ganglion axons attempting to grow from astrocytes to meningeal cells was blocked, but axons grew rapidly from meningeal cells onto astrocytes. Meningeal cells were examined for expression of axon growth inhibitory molecules, and found to express NG2, versican, and semaphorins 3A and 3C. Astrocytes express growth promoting molecules, including N-Cadherin, laminin, fibronectin, and tenascin-C. We treated cultures in various ways to attempt to promote axon growth across the inhibitory boundaries. Blockade of NG2 with antibody and blockade of neuropilin 2 but not neuropilin 1 both promoted axon growth from astrocytes to meningeal cells. Blockade of permissive molecules on astrocytes with N-Cadherin blocking peptide or anti beta-1 integrin had no effect. Manipulation of axonal signalling pathways also increased axon growth from astrocytes to meningeal cells. Increasing cAMP levels and inactivation of rho were both effective when the cultures were fixed in paraformaldehyde, demonstrating that their effect is on axons and not via effects on the glial cells.

Versican is upregulated in CNS injury and is a product of oligodendrocyte lineage cells.

Chondroitin sulfate proteoglycan (CS-PG) expression is increased in response to CNS injury and limits the capacity for axonal regeneration. Previously we have shown that neurocan is one of the CS-PGs that is upregulated (Asher et al., 2000). Here we show that another member of the aggrecan family, versican, is also upregulated in response to CNS injury. Labeling of frozen sections 7 d after a unilateral knife lesion to the cerebral cortex revealed a clear increase in versican immunoreactivity around the lesion. Western blot analysis of extracts prepared from injured and uninjured tissue also revealed considerably more versican in the injured tissue extract. In vitro studies revealed versican to be a product of oligodendrocyte lineage cells (OLCs). Labeling was seen between the late A2B5-positive stage and the O1-positive pre-oligodendrocyte stage. Neither immature, bipolar A2B5-positive cells, nor differentiated, myelin-forming oligodendrocytes were labeled. The amount of versican in conditioned medium increased as these cells differentiated. Versican and tenascin-R colocalized in OLCs, and coimmunoprecipitation indicated that the two exist as a complex in oligodendrocyte-conditioned medium. Treatment of pre-oligodendrocytes with hyaluronidase led to the release of versican, indicating that its retention at the cell surface is dependent on hyaluronate (HA). In rat brain, approximately half of the versican is bound to hyaluronate. We also provide evidence of a role for CS-PGs in the axon growth-inhibitory properties of oligodendrocytes. Because large numbers of OLCs are recruited to CNS lesions, these results suggest that OLC-derived versican contributes to the inhospitable environment of the injured CNS.