Field comparisons of photosynthesis and leaf conductance in Ziziphus mauritiana and other fruit tree species in Zimbabwe

 Data are presented for gas exchange in exposed leaves in field grown Ziziphus mauritiana (Lamk.) at a highland site and potted seedlings at a hotter lowland site in tropical Zimbabwe, together with indigenous and locally-grown commercial fruit crops. The field trial at the highland site included local Ziziphus mauritiana, introduced Indian Z. mauritiana (cv. Umran), fig and peach. In all species assimilation was highest early in the morning, followed by a gradual decline throughout the remainder of the day. Leaf conductance followed the same trend as assimilation for fig and peach, but in Ziziphus cv. Umran and Ziziphus Musau, conductance tracked irradiance, reaching a maximum in the middle of the day. In all species, sub-stomatal CO₂ concentrations increased with declining assimilation indicating that during high irradiance, assimilation was mainly controlled by mesophyll limitations rather than conductance. At the highland site both Ziziphus cv. Umran and Musau were highly productive, with light saturated assimilation significantly higher than in either fig or peach (P < 0.01). At the warmer lowland site, assimilation and conductance in Ziziphus Musau were also higher than in other indigenous fruit tree species growing under similar conditions. Despite increased assimilation in Ziziphus, when compared to the other species, there was no increase in the assimilation ratio (ratio of assimilation/conductance) which was offset by the high conductance values. The data indicate that under conditions where water was not limiting, young Ziziphus showed no enhanced stomatal control over water loss, but was highly productive (per unit leaf area) relative to the other species. Received: 17 October 1996 / Accepted: 8 January 1997     

Anti-cooperativity in the two electron oxidation of the S118C disulfide dimer of azurin

We have constructed a disulfide dimer of S118C azurin, in which two copper centers are coupled through a relatively short covalent pathway, and studied its electron transfer properties. The dimer exhibits intriguing mechanistic properties. Due to the strain in the molecule, caused by the limited accessibility of Cys118, anti-cooperativity occurs in the two step oxidation of the dimer with a difference in redox potential between the two half reactions of 33 mV. Upon oxidation, the dimer favours the semi-reduced over the fully oxidized state, as the Cu(I) site in the semi-reduced dimer is able to stabilize the strained dimer complex. The internal electron transfer is surprisingly slow, which could be partially due to an increase in reorganization energy.     

Difference in Aneurysm Characteristics between Patients with Familial and Sporadic Aneurysmal Subarachnoid Haemorrhage

ObjectPatients with familial intracranial aneurysms (IA) have a higher risk of rupture than patients with sporadic IA. We compared geometric and morphological risk factors for aneurysmal rupture between patients with familial and sporadic aneurysmal subarachnoid hemorrhage (aSAH) to analyse if these risk factors contribute to the increased rupture rate of familial IA.MethodsGeometric and morphological aneurysm characteristics were studied on CT-angiography in a prospectively collected series of patients with familial and sporadic aSAH, admitted between September 2006 and September 2009, and additional patients with familial aSAH retrieved from the prospectively collected database of familial IA patients of our center. Odds ratios (OR) with corresponding 95% confidence intervals (95% CI) were calculated to compare the aneurysm characteristics between patients with familial and sporadic aSAH.ResultsWe studied 67 patients with familial and 184 with sporadic aSAH. OR’s for familial compared with sporadic aSAH were for oval shape 1.16(95%CI:0.65–2.09), oblong shape 0.26(95%CI:0.03–2.13), irregular shape 0.83(95%CI:0.47–1.49), aspect ratio ≥ 1.6 0.94(95%CI:0.54–1.66), contact with the perianeurysmal environment (PAE) 1.15(95%CI:0.56–2.40), deformation by the PAE 1.05(95%CI:0.47–2.35) and for dominance of the posterior communicating artery (PCoA) in case of PCoA aneurysms 1.97(95% CI:0.50–7.83).ConclusionsThe geometric and morphological risk factors for aneurysm rupture do not have a higher prevalence in familial than in sporadic aSAH and thus do not explain the increased risk of IA rupture in patients with familial IA. We recommend further search for other potential risk factors for rupture of familial IA, such as genetic factors.     

Generation and characterization of a novel recombinant scFv antibody specific for Campylobacter jejuni

Applied Microbiology and Biotechnology - Campylobacter jejuni is a leading cause of foodborne illness worldwide, mainly due to consumption and handling of contaminated raw chicken. Rapid detection...     

Optimisation of a potency assay for the assessment of immunomodulative potential of clinical grade multipotent mesenchymal stromal cells

Clinical use of multipotent Mesenchymal Stromal Cell (MSC)-based medicinal products requires their production in compliance with Good Manufacturing Practices, thus ensuring that the final drug product meets specifications consistently from batch to batch in terms of cell viability, identity, purity and potency. Potency relates to the efficacy of the medicine in its target clinical indication, so adequate release tests need to be defined and validated as quality controls. Herein we report the design and optimisation of parameters affecting the performance of an in vitro cell-based assay for assessing immunomodulatory potential of clinical grade MSC for human use, based on their capacity to inhibit proliferation of T lymphocytes under strong polyclonal stimuli. The resulting method was demonstrated to be reproducible and relatively simple to execute. Two case studies using clinical grade MSC are presented as examples to illustrate the applicability of the methodology described in this work.     

Eight-Year Follow-Up of Neuropsychiatric Symptoms and Brain Structural Changes in Fabry Disease

Brain structural alterations and neuropsychiatric symptoms have been described repeatedly in Fabry disease, yet cognitive deficits have been shown to be only mild. Here, we aimed to investigate neuropsychiatric symptoms and brain structure longitudinally. We expected no clinically relevant increase of neuropsychiatric symptoms in parallel to increased brain structural alterations. We assessed 14 Fabry patients (46.1 ± 10.8 years) who had participated in our investigation eight years ago. Patients engaged in neuropsychiatric testing, as well as structural magnetic resonance imaging and angiography to determine white matter lesions, hippocampal volume, and the diameter of the larger intracranial arteries. While Fabry patients did not differ on cognitive performance, they showed progressive and significant hippocampal volume loss over the 8-year observation period. White matter lesions were associated with older age and higher white matter lesion load at baseline, but did not reach statistical significance when comparing baseline to follow-up. Likewise, intracranial artery diameters did not increase significantly. None of the imaging parameters were associated with the neuropsychiatric parameters. Depression frequency reduced from 50% at baseline to 21% at follow-up, but it did not reach significance. This investigation demonstrates clinical stability in cognitive function, while pronounced hippocampal atrophy is apparent throughout the 8 years. Our middle-aged Fabry patients appeared to compensate successfully for progressive hippocampal volume loss. The hippocampal volume decline indicates brain regional neuronal involvement in Fabry disease.