Spinal Motion and Muscle Activity during Active Trunk Movements – Comparing Sheep and Humans Adopting Upright and Quadrupedal Postures

Sheep are used as models for the human spine, yet comparative in vivo data necessary for validation is limited. The purpose of this study was therefore to compare spinal motion and trunk muscle activity during active trunk movements in sheep and humans. Three-dimensional kinematic data as well as surface electromyography (sEMG) of spinal flexion and extension was compared in twenty-four humans in upright (UR) and 4-point kneeling (KN) postures and in 17 Austrian mountain sheep. Kinematic markers were attached over the sacrum, posterior iliac spines, and spinous and transverse processes of T5, T8, T11, L2 and L5 in humans and over the sacrum, tuber sacrale, T5, T8, T12, L3 and L7 in sheep. The activity of erector spinae (ES), rectus abdominis (RA), obliquus externus (OE), and obliquus internus (OI) were collected. Maximum sEMG (MOE) was identified for each muscle and trial, and reported as a percentage (MOE%) of the overall maximally observed sEMG from all trials. Spinal range of motion was significantly smaller in sheep compared to humans (UR / KN) during flexion (sheep: 6–11°; humans 12–34°) and extension (sheep: 4°; humans: 11–17°). During extension, MOE% of ES was greater in sheep (median: 77.37%) than UR humans (24.89%), and MOE% of OE and OI was greater in sheep (OE 76.20%; OI 67.31%) than KN humans (OE 21.45%; OI 19.34%), while MOE% of RA was lower in sheep (21.71%) than UR humans (82.69%). During flexion, MOE% of RA was greater in sheep (83.09%) than humans (KN 47.42%; UR 41.38%), and MOE% of ES in sheep (45.73%) was greater than KN humans (14.45%), but smaller than UR humans (72.36%). The differences in human and sheep spinal motion and muscle activity suggest that caution is warranted when ovine data are used to infer human spine biomechanics.     

The MsK family of alfalfa protein kinase genes encodes homologues of shaggy/glycogen synthase kinase-3 and shows differential expression patterns in plant organs and development

This paper reports on the isolation of a novel class of plant serine/threonine protein kinase genes, MsK-1 , MsK-2 and MsK-3 . They belong to the superfamily of cdc2 -like genes, but show highest identity to the Drosophila shaggy and rat GSK-3 proteins (66–70%). All of these kinases share a highly conserved catalytic protein kinase domain. Different amino-terminal extensions distinguish the different proteins. The different plant kinases do not originate from differential processing of the same gene as is found for shaggy , but are encoded by different members of a gene family. Similarly to the shaggy kinases, the plant kinases show different organ-specific and stage-specific developmental expression patterns. Since the shaggy kinases play an important role in intercellular communication in Drosophila development, the MsK kinases are expected to perform a similar function in plants.     

Applicability of the WHO Maternal Near Miss Criteria in a Low-Resource Setting

Background

Maternal near misses are increasingly used to study quality of obstetric care. Inclusion criteria for the identification of near misses are diverse and studies not comparable. WHO developed universal near miss inclusion criteria in 2009 and these criteria have been validated in Brazil and Canada.

Objectives

To validate and refine the WHO near miss criteria in a low-resource setting.

Methods

A prospective cross-sectional study was performed in a rural referral hospital in Tanzania. From November 2009 until November 2011, all cases of maternal death (MD) and maternal near miss (MNM) were included. For identification of MNM, a local modification of the WHO near miss criteria was used, because most laboratory-based and some management-based criteria could not be applied in this setting. Disease-based criteria were added as they reflect severe maternal morbidity. In the absence of a gold standard for identification of MNM, the clinical WHO criteria were validated for identification of MD.

Results

32 MD and 216 MNM were identified using the locally adapted near miss criteria; case fatality rate (CFR) was 12.9%. WHO near miss criteria identified only 60 MNM (CFR 35.6%). All clinical criteria, 25% of the laboratory-based criteria and 50% of the management-based criteria could be applied. The threshold of five units of blood for identification of MNM led to underreporting of MNM. Clinical criteria showed specificity of 99.5% (95%CI: 99.4%–99.7%) and sensitivity of 100% (95%CI: 91.1%–100%). Some inclusion criteria did not contribute to the identification of cases and therefore may be eligible for removal.

Conclusion

The applicability of the WHO near miss criteria depends on the local context, e.g. level of health care. The clinical criteria showed good validity. Lowering the threshold for blood transfusion from five to two units in settings without blood bank and addition of disease-based criteria in low-resource settings is recommended.     

Abi1 is essential for the formation and activation of a WAVE2 signalling complex

WAVE2 belongs to a family of proteins that mediates actin reorganization by relaying signals from Rac to the Arp2/3 complex, resulting in lamellipodia protrusion. WAVE2 displays Arp2/3-dependent actin nucleation activity in vitro, and does not bind directly to Rac. Instead, it forms macromolecular complexes that have been reported to exert both positive and negative modes of regulation. How these complexes are assembled, localized and activated in vivo remains to be established. Here we use tandem mass spectrometry to identify an Abi1-based complex containing WAVE2, Nap1 (Nck-associated protein) and PIR121. Abi1 interacts directly with the WHD domain of WAVE2, increases WAVE2 actin polymerization activity and mediates the assembly of a WAVE2-Abi1-Nap1-PIR121 complex. The WAVE2-Abi1-Nap1-PIR121 complex is as active as the WAVE2-Abi1 sub-complex in stimulating Arp2/3, and after Rac activation it is re-localized to the leading edge of ruffles in vivo. Consistently, inhibition of Abi1 by RNA interference (RNAi) abrogates Rac-dependent lamellipodia protrusion. Thus, Abi1 orchestrates the proper assembly of the WAVE2 complex and mediates its activation at the leading edge in vivo.     

Serum-free generation of antigen presenting cells from acute myeloid leukaemic blasts for active specific immunisation

PURPOSE: Immunotherapy holds promise as a new strategy for the eradication of residual cells in acute myeloid leukaemia (AML). Leukaemic antigen presenting cells (APCs) combining optimal antigen presentation and tumour antigenicity could be used as potent T cell activators. For clinical purposes it is desirable to culture APCs under serum-free conditions. Therefore, we compared morphological, immunophenotypical and functional outcome of the serum-free culture of AML-APCs to their serum-enriched culture. METHODS: AML blasts (n=19) were cultured in the presence of either a cytokine mix or calcium ionophore (CI) for 14 and 2 days, respectively, in FCS-containing medium (FCS), StemSpan serum-free medium (SP) and CellGro serum-free medium (CG). After culture relative yields were calculated and immunophenotypic analysis of APC markers was performed. The mixed leukocyte reaction (MLR) was used to determine T cell stimulating capacity. RESULTS: Serum-free culture of AML-APCs resulted in comparable morphology, relative yields and immunophenotype to serum-enriched culture. By comparing both serum-free media we observed a trend towards a more mature phenotype of CI-cultured AML-APCs in SP. MLR showed that serum-free cultured cells have equal T cell stimulatory capacity in comparison with serum-enriched culture. CONCLUSION: These data show that the serum-free culture of AML-APCs is feasible and that these APCs are comparable to serum-enriched cultured AML-APCs with regard to morphological, immunophenotypical and functional characteristics. These AML-APCs are suitable for the development of active specific immunisation protocols which meet the criteria for good clinical practise (GCP).