The Mr 95,000 gelatin-binding protein in differentiated human macrophages and granulocytes

Cultured adherent human macrophages and a promonocytic cell line, U 937, were previously shown to produce a Mr 95,000 gelatin-binding protein. The protein has no immunologic cross-reactivity with the well- characterized gelatin-binding protein fibronectin and the Mr 70,000 gelatin-binding protein produced by a variety of mesenchymal or epithelial cell types (T. Vartio et al, J Biol Chem 257:8862, 1982). In the present study the Mr 95,000 protein was found in Triton X-100 extracts of granulocytes purified from human blood buffy coat. The protein, as isolated by gelatin-agarose, was immunologically cross- reactive with the corresponding macrophage protein in immunoblotting assay. When peripheral blood and bone marrow cells were examined for the presence of the Mr 95,000 protein by indirect immunofluorescence, positive staining was detected only in differentiated granulocytes but not to any significant extent in metamyelocytes, myelocytes, promyelocytes, or in normal or leukemic blasts. In granulocytes the protein had a granular cytoplasmic distribution. In freshly prepared monocyte cultures, the Mr 95,000 protein was detected in low amounts in the cytoplasm, while along with differentiation of the cells into macrophages, the immunofluorescence increased in a reticular and vesicular cytoplasmic pattern and in a juxtanuclear cap, probably representing the Golgi complex. In conclusion, the Mr 95,000 gelatin- binding protein was specifically detected in macrophages and granulocytes and may thus serve as a differentiation marker for these phagocytic cells.     

In vitro and in vivo evaluation of heparin mediated growth factor release from tissue‐engineered constructs for anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) rupture is a common injury often necessitating surgical treatment with graft reconstruction. Due to limitations associated with current graft options, there is interest in a tissue‐engineered substitute for use in ACL regeneration. While they represent an important step in translation to clinical practice, relatively few in vivo studies have been performed to evaluate tissue‐engineered ACL grafts. In the present study, we immobilized heparin onto electrospun polycaprolactone scaffolds as a means of incorporating basic fibroblast growth factor (bFGF) onto the scaffold. In vitro, we demonstrated that human foreskin fibroblasts (HFFs) cultured on bFGF‐coated scaffolds had significantly greater cell proliferation. In vivo, we implanted electrospun polycaprolactone grafts with and without bFGF into athymic rat knees. We analyzed the regenerated ACL using histological methods up to 16 weeks post‐implantation. Hematoxylin and eosin staining demonstrated infiltration of the grafts with cells, and picrosirius red staining demonstrated aligned collagen fibers. At 16 weeks postop, mechanical testing of the grafts demonstrated that the grafts had approximately 30% the maximum load to failure of the native ACL. However, there were no significant differences observed between the graft groups with or without heparin‐immobilized bFGF. While this study demonstrates the potential of a regenerative medicine approach to treatment of ACL rupture, it also demonstrates that in vitro results do not always predict what will occur in vivo. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:229–236, 2015.     

Mechanism of inositol monophosphatase, the putative target of lithium therapy.

myo-Inositol monophosphatase (myo-inositol-1-phosphate phosphohydrolase, EC 3.1.3.25) is an attractive target for mechanistic investigation due to its critical role in the phosphatidylinositol signaling pathway and the possible relevance of its inhibition by Li+ to manic depression therapy. The x-ray crystallographic structure of human inositol monophosphatase in the presence of the inhibitory metal Gd3+ showed only one metal bound per active site, whereas in the presence of Mn2+, three ions were present with one being displaced upon phosphate binding. We report here modeling, kinetic, and mutagenesis studies on the enzyme, which reveal the requirement for two metal ions in the catalytic mechanism. Activity titration curves with Zn2+ or Mn2+ in the presence or absence of Mg2+ are consistent with a two-metal mechanism. Modeling studies based on the various x-ray crystallographic structures (including those with Gd3+ and substrate bound) further support a two-metal mechanism and define the positions of the two metal ions relative to substrate. While the first metal ion may activate water for nucleophilic attack, a second metal ion, coordinated by three aspartate residues, appears to act as a Lewis acid, stabilizing the leaving inositol oxyanion. In this model, the 6-OH group of substrate acts as a ligand for this second metal ion, consistent with the reduced catalytic activity observed with substrate analogues lacking the 6-OH. Evidence from Tb3+ fluorescence quenching and the two-metal kinetic titration curves suggests that Li+ binds at the site of this second metal ion.     

Risk of transmission associated with sharing drug injecting paraphernalia: analysis of recent hepatitis C virus (HCV) infection using cross‐sectional survey data

Sharing injecting paraphernalia (containers, filters and water) poses a risk of transmitting the hepatitis C virus (HCV). The prevalence of, and risk of HCV from, such behaviour has not been extensively reported in Europe. People who inject drugs (PWID) were recruited in cross‐sectional surveys from services providing sterile injecting equipment across Scotland between 2008 and 2010. Participants completed a questionnaire and provided a blood spot for anonymous testing. Logistic regression was used to examine the association between recent HCV infection (anti‐HCV negative and HCV‐RNA positive) and self‐reported measures of injecting equipment sharing in the 6 months preceding interview. Twelve per cent of the sample reported sharing needles/syringes, and 40% reported sharing paraphernalia in the previous 6 months. The adjusted odds ratios (AOR) for sharing needles/syringes (+/− paraphernalia), and sharing only paraphernalia in the last 6 months were 6.7 (95% CI 2.6–17.1) and 3.0 (95% CI 1.2–7.5), respectively. Among those who reported not sharing needles/syringes, sharing containers and filters were both significantly associated with recent HCV infection (AOR 3.1, 95% CI 1.3–7.8 and 3.1, 95% CI 1.3–7.5, respectively); sharing water was not. We present the first study to apply a cross‐sectional approach to the analysis of the association between sharing paraphernalia and incident HCV infection and demonstrate consistent results with previous longitudinal studies. The prevalence of paraphernalia sharing in our study population is high, representing significant potential for HCV transmission.     

Alterations in Immune Cells and Mediators in the Brain: It's Not Always Neuroinflammation!

Neuroinflammation was once a clearly defined term denoting pathological immune processes within the central nervous system (CNS). Historically, this term was used to indicate the four hallmarks of peripheral inflammaton that occur following severe CNS injuries, such as stroke, injury or infection. Recently, however, the definition of neuroinflammation has relaxed to the point that it is often now assumed to be present when even only a single classical hallmark of inflammation is measured. As a result, a wide range of disorders, from psychiatric to degenerative diseases, are now assumed to have an integral inflammatory component. Ironically, at the same time, research has revealed unexpected nonclassical immune actions of immune mediators and cells in the CNS in the absence of pathology, increasing the likelihood that homeostatic and adaptive immune processes in the CNS will be mistaken for neuroinflammation. Thus, we suggest reserving the term neuroinflammation for contexts where multiple signs of inflammation are present to avoid erroneously classifying disorders as inflammatory when they may instead be caused by nonimmune etiologies or secondary immune processes that serve adaptive roles.     

Diagnosis of myocardial infarction following hospitalisation for exacerbation of COPD

Cardiovascular disease is common in chronic obstructive pulmonary disease (COPD) and raised troponin is common in exacerbations. However, the prevalence of myocardial infarction following hospitalisation for exacerbation of COPD is unknown. Patients aged ≥ 40 yrs hospitalised with acute exacerbation of COPD (n = 242) with ≥ 10 pack-yrs of cigarette smoking were included in a prospective case series conducted in four hospitals. Patients whose primary presenting complaint was chest pain or who had an alternative diagnosis were excluded. Chest pain histories, serial ECGs and troponin levels were obtained. The mean ± SD age was 69 ± 9 yrs; 108 (45%) patients were male and almost half were current smokers. 124 (51%; 95% CI 48-58%) patients had chest pain, which was exertional in 62 (26%). 24 (10%) had raised troponin, among whom, 20 (8.3%; 95% CI 5.1-12.5%) had chest pain and/or serial ECG changes, fulfilling the 2007 Universal Definition of Myocardial Infarction. Neither chest pain (p = 0.77) nor serial ECG changes (p = 0.39) were associated with raised troponin. Raised troponin, chest pain and serial ECG changes are common in patients admitted to hospital with exacerbation of COPD. Overall, one in 12 patients met the criteria for myocardial infarction. Whether these patients would benefit from further cardiac investigation is unknown.