Ucma, a novel secreted cartilage-specific protein with implications in osteogenesis

Here we report on the structure, expression, and function of a novel cartilage-specific gene coding for a 17-kDa small, highly charged, and secreted protein that we termed Ucma (unique cartilage matrix-associated protein). The protein is processed by a furin-like protease into an N-terminal peptide of 37 amino acids and a C-terminal fragment (Ucma-C) of 74 amino acids. Ucma is highly conserved between mouse, rat, human, dog, clawed frog, and zebrafish, but has no homology to other known proteins. Remarkable are 1-2 tyrosine sulfate residues/molecule and dense clusters of acidic and basic residues in the C-terminal part. In the developing mouse skeleton Ucma mRNA is expressed in resting chondrocytes in the distal and peripheral zones of epiphyseal and vertebral cartilage. Ucma is secreted into the extracellular matrix as an uncleaved precursor and shows the same restricted distribution pattern in cartilage as Ucma mRNA. In contrast, antibodies prepared against the processed C-terminal fragment located Ucma-C in the entire cartilage matrix, indicating that it either diffuses or is retained until chondrocytes reach hypertrophy. During differentiation of an MC615 chondrocyte subclone in vitro, Ucma expression parallels largely the expression of collagen II and decreases with maturation toward hypertrophic cells. Recombinant Ucma-C does not affect expression of chondrocyte-specific genes or proliferation of chondrocytes, but interferes with osteogenic differentiation of primary osteoblasts, mesenchymal stem cells, and MC3T3-E1 pre-osteoblasts. These findings suggest that Ucma may be involved in the negative control of osteogenic differentiation of osteochondrogenic precursor cells in peripheral zones of fetal cartilage and at the cartilage-bone interface.     

Regulation of GABA Metabolism in Discrete Rabbit Brain Regions under Methoxypyridoxine—Regional Differences in Cofactor Saturation and the Preictal Activation of Glutamate Decarboxylase Activity1

Abstract: The activities of the enzymes of the GABA system, glutamate decarboxylase (GAD) and GABA-transaminase, were measured in discrete regions of the rabbit brain before the onset and during the course of sustained epileptiform seizures induced by the vitamin B₆, analogue methoxypyridoxine (MP). GAD activities were measured in a reaction mixture alternatively containing the cofactor pyridoxal-5′-phosphate (PLP) in excess or containing no PLP (holoenzyme of GAD). A comparison between these two estimations showed that the apoenzyme of GAD is only partially saturated with cofactor and that the degree of saturation varied from brain area to brain area, being highest in cerebellar cortex and lowest in substantia nigra. Holoenzyme activity fell steeply after administration of 100 mg/kg MP. The regional degree of enzyme inhibition by MP was a function of the saturation of the apoenzyme with cofactor; i.e., a low rate of saturation resulted in a high degree of inhibition, and vice versa. That GAD from the regio inferior of the hippocampus did not fit into the scheme (strong inhibition is present although the degree of saturation is high) is discussed in view of the role of the hippocampus in seizure genesis and generalization. Inhibition of GAD activity by MP was completely reversible in vitro by excess PLP. Before the onset of seizures but not during their course, apoenzyme activity surpassed control levels. This preictal activation is significant in regio inferior of hippocampus, in superior colliculus, and in cerebellar cortex. GABA-transaminase activities were not significantly altered. The present study demonstrates that only investigation during the preictal period and in regional brain areas can reveal changes specific for the drug and perhaps representing the cause for seizure development, without being masked by additional alterations resulting from the severe functional and metabolic derangement during the ictal events. Thereby, it was disclosed that a decrease in vivo in the level of the enzyme product, GABA, is able to activate GAD.     

Evaluation of a structured treatment discontinuation in patients with inoperable alveolar echinococcosis on long-term benzimidazole therapy: A retrospective cohort study

ObjectivesAlveolar echinococcosis (AE) is an orphan zoonosis of increasing concern in endemic areas, including Europe. It frequently presents in an advanced, inoperable stage, that requires life-long parasitostatic benzimidazole therapy. In some patients, long-term therapy leads to negative anti-Em18 antibody ELISA and PET. It is disputed, whether these patients are truly cured and treatment can be safely discontinued. Our aim was to retrospectively assess long-term outcome of 34 patients with inoperable AE who participated in a previous study to determine feasibility of benzimidazole treatment cessation.MethodsRetrospective analysis of medical charts was undertaken in all 34 AE patients who participated in our previous study. Of particular interest were AE recurrence or other reasons for re-treatment in patients who stopped benzimidazole therapy and whether baseline clinical and laboratory parameters help identify of patients that might qualifiy for treatment cessation. Additionally, volumetric measurement of AE lesions on contrast-enhanced cross-sectional imaging was performed at baseline and last follow-up in order to quantify treatment response.Results12 of 34 patients stopped benzimidazole therapy for a median of 131 months. 11 of these patients showed stable or regressive AE lesions as determined by volumetric measurement. One patient developed progressive lesions with persistently negative anti-Em18 antibody ELISA but slight FDG-uptake in repeated PET imaging. At baseline, patients who met criteria for treatment cessation demonstrated higher lymphocyte count and lower total IgE.ConclusionTreatment cessation is feasible in inoperable AE patients, who demonstrate negative anti-Em18 antibody ELISA and PET on follow-up. Close monitoring including sectional imaging is strongly advised.     

Immobilization of yeast cells in plant cell wall frameworks

Summary Cell-structured support materials (CSM) representing the cell framework of denaturated and extracted mosses, duckweeds or parenchyma tissue particles have been used for the immobilization of Saccharomyces cerevisiae cells. The method consists of inoculation by soaking the dehydrated materials in a yeast suspension and propagation of the yeast cells that reach the relatively closed inner volumes of the cell-structured particles (inter- or intracellular spaces). In spite of high cell densities (up to 2.5 × 10⁹ cells/g wet immobilizate) the velocity of microaerobic glucose consumption was little influenced by intraparticular diffusion resistances, when yeast loaded CSM made from Wolffia arrhiza was incubated in 100 mM glucose at room temperature.     

Current status of clinically available bioresorbable scaffolds in percutaneous coronary interventions

Drug-eluting stents (DES) are widely used as first choice devices in percutaneous coronary interventions. However, certain concerns are associated with the use of DES, i.e. delayed arterial healing with a subsequent risk of neo-atherosclerosis, late stent thrombosis and hypersensitivity reactions to the DES polymer. Bioresorbable vascular scaffolds are the next step in percutaneous coronary interventions introducing the concept of supporting the natural healing process following initial intervention without leaving any foreign body materials resulting in late adverse events. The first-generation devices have shown encouraging results in multiple studies of selected patients up to the point of full bioresorption, supporting the introduction in regular patient care. During its introduction in daily clinical practice outside the previously selected patient groups, a careful approach should be followed in which outcome is continuously monitored.     

Appropriate use of bioresorbable vascular scaffolds in percutaneous coronary interventions: a recommendation from experienced users: A position statement on the use of bioresorbable vascular scaffolds in the Netherlands

Percutaneous coronary interventions (PCI) have become a reliable revascularisation option to treat ischaemic coronary artery disease. Drug-eluting stents (DES) are widely used as first choice devices in many procedures due to their established good medium to long term outcomes. These permanent implants, however, do not have any residual function after vascular healing following the PCI. Beyond this initial healing period, metallic stents may induce new problems, resulting in an average rate of 2 % reinterventions per year. To eliminate this potential late limitation of permanent metallic DES, bioresorbable coronary stents or ‘vascular scaffolds’ (BVS) have been developed. In a parallel publication in this journal, an overview of the current clinical performance of these scaffolds is presented. As these scaffolds are currently CE marked and commercially available in many countries and as clinical evidence is still limited, recommendations for their general usage are needed to allow successful clinical introduction.     

Differential expression of two paralogous genes of Bacillus subtilis encoding single-stranded DNA binding protein

The Bacillus subtilis genome comprises two paralogous single-stranded DNA binding protein (SSB) genes, ssb and ywpH, which show distinct expression patterns. The main ssb gene is strongly expressed during exponential growth and is coregulated with genes encoding the ribosomal proteins S6 and S18. The gene organization rpsF-ssb-rpsR as observed in B. subtilis is found in many gram-positive as well as some gram-negative bacteria, but not in Escherichia coli. The ssb gene is essential for cell viability, and like other SSBs its expression is elevated during SOS response. In contrast, the paralogous ywpH gene is transcribed from its own promoter at the onset of stationary phase in minimal medium only. Its expression is ComK dependent and its gene product is required for optimal natural transformation.