High resolution of heterogeneity among human neutrophil granules: physical, biochemical, and ultrastructural properties of isolated fractions

Previous studies on the fractionation of human neutrophil granules have identified two major populations: myeloperoxidase (MPO)-containing azurophil, or primary, granules and MPO-deficient specific, or secondary, granules. Peripheral blood neutrophils from individual donors were lysed in sucrose-free media by either hypotonic shock or nitrogen cavitation. Using a novel two-gradient Percoll density centrifugation system, the granule-rich postnuclear supernatant was rapidly (ten minutes) and reproducibly resolved into 13 granule fractions (L1 through L8 and H1 through H5). Granule flotation and recentrifugation experiments on both continuous, self-generated and multiple-step gradients using individual and mixed isolated fractions demonstrated that the banding patterns were isopycnic and nonartifactual. Isolated granules were intact based on the findings that biochemical latency of several granule enzymes was greater than 95%, and thin-sectioned electron micrographs demonstrated intact granule profiles. Biochemical analyses of the granule marker proteins MPO, beta-glucuronidase, lysozyme, and lactoferrin indicated that a number of the fractions were related to the major azurophil and specific granule populations. Lactoferrin was found in ten of 13 fractions (L1 through L8, H1 to H2), whereas MPO was found in every fraction. Consistent with these biochemical data, all fractions exhibited varying degrees of heterogeneity based on ultrastructural morphology and cytochemistry, including diaminobenzidine (DAB) reactivity for peroxidase and periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining for complex glycoconjugates. A variable but significant percentage (23% to 70%) of the granules in fractions L1 through L8 and H1 and H2 showed DAB reactivity, while about 90% of the granules in fractions H3 through H5 were peroxidase positive. These results demonstrated that DAB-reactive granules spanned the entire range of granule size and density. Ultrastructural PA-TCH-SP staining of isolated granule fractions revealed patterns similar to those of granules in intact neutrophils at different stages of development. Granules from human acute promyelocytic leukemia cells (HL-60) exhibited a surprisingly low density compared with typical azurophil granules from normal, mature neutrophils. The data suggest that both functional and maturational differences contribute to granule heterogeneity, and provide a new practical and conceptual framework for further defining the phenomenon of neutrophil granule heterogeneity.     

Nucleotide metabolic mismatches in mammalian hearts: implications for transplantation

Introduction

Human donor organ shortages have led surgeons and scientists to explore the use of animals as alternative organ sources. Acute thrombovascular rejection (AVR) is the main hurdle in xenotransplantation. Disparities in nucleotide metabolism in the vessels of different species may contribute significantly to the microvascular component of AVR.

Methods

We evaluated the extent of nucleotide metabolism mismatch in selected organs and endothelial cells of different mammals with particular focus on the changes in activity of ecto-5’-nucleotidase (E5’N) elicited by exposure of porcine hearts or endothelial cells to human blood (ex vivo) or human plasma (in vitro).

Results

E5’N activity in the rat heart was significantly higher than in other species. We noted a significant difference (p<0.001) in E5’N activity between human and pig endothelial cell lines. Initial pig aortic endothelial E5’N activity decreased in vitro after a three-hour exposure to human and porcine plasma while remaining constant in controls. Ex vivo perfusion with fresh human blood for four hours resulted in a significant decrease of E5’N activity in both wild type and transgenic pig hearts overexpressing human decay accelerating factor (p<0.001).

Conclusions

This study provides evidence that mismatches in basal mammalian metabolic pathways and humoral immunity interact in a xenogeneic environment. Understanding the role of nucleotide metabolism and signalling in xenotransplantation may identify new targets for genetic modifications and may lead to the development of new therapies extending graft survival.     

Limitation of repeated radiofrequency ablation in hepatocellular carcinoma: proposal of a three (times) × 3 (years) index

Background and Aim: Percutaneous radiofrequency ablation (RFA) has been shown to be a highly effective treatment for hepatocellular carcinoma (HCC). We investigated the controllability of HCC and explored the algorithm of therapeutic strategy for HCC in patients who met the RFA criteria. Methods: We enrolled 472 patients with HCC who met the RFA criteria (≤ 3 nodules, ≤ 3 cm) and underwent RFA for initial therapy. Patients who underwent repeated RFA were evaluated retrospectively when HCC exceeded the RFA criteria, or the functional hepatic reserve progressed to Child–Pugh grade C. Results: Overall survival rates were: 1 year, 96%; 3 years, 79%; and 5 years, 56%. In 5 years, 14% of patients progressed to Child–Pugh grade C. Meanwhile, 47% of patients exceeded the RFA criteria. Annually, 8% of patients deviated from the RFA criteria. The percentage of patients who were able to receive RFA significantly decreased at the fourth session compared with up to the third session. The survival rates decreased at the rate of 7% annually until the third year after the initial RFA. Afterwards, it shifted to a decrease at the rate of 12% annually. In a multivariate analysis, the presence of hepatitis C virus infection and the existence of a single tumor were identified as significant independent factors contributing to probabilities exceeding the RFA criteria. Conclusions: HCC was controlled by RFA up to three RFA treatments and 3 years from the initial therapy. On this basis, we propose a “three (times) × 3 (years) index” for considering a shift from RFA to other treatment modalities.     

Donor–acceptor random regioregular π-conjugated copolymers based on poly(3-hexylthiophene) with unsymmetrical monothienoisoindigo units

Donor–acceptor π-conjugated random copolymers based on regioregular poly(3-hexylthiophene), rr-P3HT, with unsymmetrical monothienoisoindigo moieties were obtained by direct arylation polycondensation of 2-bromo-3-hexylthiophene with unsymmetrical monothienoisoindigo motifs under the optimized conditions [palladium-immobilized on thiol-modified silica gel with chloride counter anions, PITS-Cl (2.5 mol%), PivOH (1.0 equiv.), K₂CO₃ (3.0 equiv.), DMAc, 100 °C, 24 h]. Incorporation of unsymmetrical monothienoisoindigo electron-acceptor units into the polymers tuned their highest occupied and lowest unoccupied molecular orbital levels, which were close to those of the hole transport material (PEDOT) and electron transport material (PCBM), respectively, in thin-film organic solar cells. Alkyl chains of the unsymmetrical monothienoisoindigo units in the polymers tuned their macrostructural order, resulting in the observation of crystalline patterns and specific absorption peaks in thin films. An organic solar cell containing the most crystalline random copolymer showed an efficiency of 1.91%.

Donor–acceptor π-conjugated random copolymers based on regioregular poly(3-hexylthiophene) with unsymmetrical monothienoisoindigo moieties were obtained by direct arylation polycondensation.