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After about 120 days of circulation in the blood stream, erythrocytes are cleared by macrophages in the spleen and the liver. The “eat me” signal of this event is thought to be the translocation of phosphatidylserine from the inner to the outer membrane leaflet due to activation of the scramblase, while the flippase is inactivated. Both processes are triggered by an increased intracellular Ca2+ concentration. Although this is not the only mechanism involved in erythrocyte clearance, in this minireview, we focus on the following questions: Is the intracellular-free Ca2+ concentration and hence phosphatidylserine exposure dependent on the erythrocyte age, i.e. is the Ca2+ concentration, progressively raising during the erythrocyte aging in vivo? Can putative differences in intracellular Ca2+ and exposure of phosphatidylserine to the outer membrane leaflet be measured in age separated cell populations? Literature research revealed less than dozen of such publications with vastly contradicting results for the Ca2+ concentrations but consistency for a lack of change for the phosphatidylserine exposure. Additionally, we performed reanalysis of published data resulting in an ostensive illustration of the situation described above. Relating these results to erythrocyte physiology and biochemistry, we can conclude that the variation of the intracellular free Ca2+ concentration is limited with 10 μM as the upper level of the concentration. Furthermore, we propose the hypothesis that variations in measured Ca2+ concentrations may to a large extent depend on the experimental conditions applied but reflect a putatively changed Ca2+ susceptibility of erythrocytes in dependence of in vivo cell age.

Aim Epidermal growth factor receptor (EGFR) mutational status is a crucial biomarker for prediction of response to tyrosine kinase inhibitors in patients with non–small cell lung cancer (NSCLC). Although these mutations have been well characterized in other countries, little is known about the frequency or spectrum of EGFR mutations in Vietnamese NSCLC patients. Methods Using Sanger DNA sequencing, we investigated mutations in EGFR exons 18–21 from 332 patients diagnosed with NSCLC at University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam. DNA was extracted from formalin-fixed, paraffin-embedded tissues, followed by PCR amplification and sequencing. Results EGFR mutations were detected in 135 samples (40.7%), of which eight samples carried double mutations. In total, 46 different types of EGFR mutations were found, including six novel mutations (p.K713E, p.K714R, p.P794S, p.R803W, p.P848S, and p.K867E). Among the four exons investigated, exon 19 was most frequently mutated (63 out of 332 patients, 19%), with the p.E746_A750del appearing in 43 samples. Exon 21 was mutated in 56 samples (16.9%), of which 47 were p.L858R. Each of exons 18 and 20 was mutated in 12 samples (3.6%). The frequency of EGFR mutations was higher in females than in males (48.9% vs 35%, P = 0.012), but not statistically different between adenocarcinomas and other histological types of NSCLC (41.3% vs 34.5%, P = 0.478). Conclusion DNA sequencing detected EGFR mutations with high frequency and revealed a broad spectrum of mutation type in Vietnamese patients with NSCLC.

Microvesicles (MVs) are small spherical fragments of plasma membrane between 50 and 1000 nm in diameter. MVs arise through direct outward budding and fission of the plasma membrane. As almost all cells, human red blood cells (RBCs) are able to release MVs into extracellular environment under stimulating or storage conditions. Recently, it has been known that MVs not only play a role in homeostasis but also have diverse functions in cell-cell interactions and in the pathogenesis of diseases. In this chapter, the formation and release of MVs from human RBCs have been described. In addition, MVs have demonstrated to be potential vehicle for transport of nucleic acid and other molecules to the target cells. Although RBC-derived MVs are potential material for the development of delivery systems, it is still a great challenge to the clinical application. Future research should pay more attention to MVs as biological targets for diagnosis and practical therapeutics of cancer and other diseases.

Epidermal growth factor receptor (EGFR) mutational status is a crucial biomarker for prediction of response to tyrosine kinase inhibitors in patients with non-small cell lung cancer (NSCLC). Although these mutations have been well characterized in other countries, little is known about the frequency or spectrum of EGFR mutations in Vietnamese NSCLC patients.Using Sanger DNA sequencing, we investigated mutations in EGFR exons 18-21 from 332 patients diagnosed with NSCLC at University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam. DNA was extracted from formalin-fixed, paraffin-embedded tissues, followed by PCR amplification and sequencing.EGFR mutations were detected in 135 samples (40.7%), of which eight samples carried double mutations. In total, 46 different types of EGFR mutations were found, including six novel mutations (p.K713E, p.K714R, p.P794S, p.R803W, p.P848S, and p.K867E). Among the four exons investigated, exon 19 was most frequently mutated (63 out of 332 patients, 19%), with the p.E746_A750del appearing in 43 samples. Exon 21 was mutated in 56 samples (16.9%), of which 47 were p.L858R. Each of exons 18 and 20 was mutated in 12 samples (3.6%). The frequency of EGFR mutations was higher in females than in males (48.9% vs 35%, P = 0.012), but not statistically different between adenocarcinomas and other histological types of NSCLC (41.3% vs 34.5%, P = 0.478).DNA sequencing detected EGFR mutations with high frequency and revealed a broad spectrum of mutation type in Vietnamese patients with NSCLC.

Genetic resources are important for the development of every country and for humanity. Collection, conservation and reasonable utilization of genetic resource is required mission. Understanding the importance of genetic resource, especially rice germplasm, since 2001, Center for conservation and development of crop genetic resources (CCD-CGR) of Hanoi University of Agriculture (Vietnam National University of Agriculture) has been collected, conserved and evaluated rice germplasm from different provinces of Vietnam for breeding programs. So far, 1090 accessions of local rice of Vietnam have been collected. Evaluation of agronomic properties and screening of some important genes using DNA molecular markers have revealed that Vietnamese rice germplasm has high level diversity and containing important genes for quality and resistance for disease and pests. These genetic resources are potential materials for national breeding programs. Based on the collected germplasm, 3 new glutinous rice varieties have been successfully created with high yield and good quality. In addition, the degradation of local rice varieties is also a matter of concern. So far, 4 specialty rice varieties Deo Dang, Ble chau, Pu de and Khau dao have been successfully restored for the north provinces of Vietnam. The main results of this study are germplasms for rice breeding programs and new improved varieties that bring economic benefits to farmers and the country. Nguồn gene là tài nguyên sống còn của mỗi quốc gia và của toàn nhân loại. Vì vậy thu thập, bảo tồn, đánh giá và khai thác hợp lý nguồn tài nguyên này có ý nghĩa rất lớn. Nhận thức được tầm quan trọng của nguồn gen nhất là nguồn gen cây lúa, ngay từ đầu những năm 2000, Trung tâm bảo tồn và phát triển nguồn gene cây trồng thuộc Trường Đại học nông nghiệp, nay là Học Viện nông nghiệp Việt Nam đã tiến hành thu thập, lưu giữ, đánh giá và khai thác nguồn gene lúa. Kết quả đã thu thập, lưu giữ được 1090 mẫu giống lúa địa phương Việt Nam. Đánh giá đặc điểm nông sinh học và phát hiện một số gene quy định các tính trạng chất lượng và kháng sâu bệnh bằng chỉ thị phân tử DNA. Đây là nguồn gene quan trọng cho chọn tạo giống. Dựa vào nguồn gene thu thập được, cho đến nay, Trung tâm bảo tồn và phát triển nguồn gene cây trồng đã lai và chọn tạo được thành công 03 giống lúa nếp chất lượng cao. Ngoài ra, thoái hóa giống cũng là vấn đề đang được quan tâm. Cho đến nay 4 giống lúa đặc sản Đèo đàng, Ble châu, Pu đe và Khẩu dao đã được phục tráng và đưa vào sản xuất. Kết quả của những nghiên cứu này là ngân hàng các giống lúa làm nguồn gene để chọn tạo giống mới đem lại lợi ích kinh tế cho người nông dân và đất nước.

Traditionally, the activity of most polysulfanes has been associated with the redox behaviour of the sulfur-sulfur bond. Here we show that polysulfanes, such as diallyltri- and tetrasulfide, also interact with cellular membranes and certain metalloproteins. Together, multiple interactions with various biological targets may explain best the biological activity of such compounds.

In the presented work the question about the role of Ca2+ in PS exposure process in RBCs has been clarified. Treatment of RBCs with LPA, A23187 and PMA in the presence of extracellular Ca2+ leads to an increase of the intracellular Ca2+ level, PS on the outer leaflet of the membrane, membrane blebbing, and microvesicle formation. These effects are influenced by the function of the phospholipid scramblase, flippase, protein kinase C and Gardos channel. It is also demonstrated that the exposure of PS does not only depend on the increase of the intracellular Ca2+ content but also on the function of protein kinase C. A model has been developed to contribute to our understanding of the mechanisms of this process. The RBCs showing PS exposure can adhere together. This may explain why RBCs adhere together during blood clot formation. It seems likely that the interaction of PS with its receptors and PS-PS in the presence of Ca2+ play a substantial role. A model to explain the process of cell-cell adhesion is presented. The hypothesis of the blood clot formation cascade developed by Kaestner and Bernhardt is also supported by experiments. The PS exposure on the outer leaflet of RBCs is an important factor for propagation the signal in clot formation process. A model in which the RBCs play an active role in blood clot formation is developed. The question about the Ca2+ content in RBCs is also answered. There is no significant difference of the free Ca2+ content in young and old RBCs. In der vorliegenden Arbeit wurde die Rolle, die Ca2+ bei der PS-Exposition spielt, geklärt. Die Behandlung roter Blutzellen mit LPA, A23187 und PMA in Gegenwart von extrazellulärem Ca2+ führt zu einem Anstieg des intrazellulären Ca2+, PS-Exposition, "Membrane Blebbing" und der Bildung von Mikrovesikeln. Diese Effekte werden beeinflusst durch die Funktion der Phospholipid Scramblase, der Flippase, der Proteinkinase C und des Gardos Kanal. Auch wurde gezeigt, dass die PS-Exposition nicht nur vom Anstieg des intrazellulären Ca2+ abhängig ist sondern auch von der Funktion der Proteinkinase C. Rote Blutzellen mit PS-Exposition können aneinander haften. Dies kann eine Erklärung dafür sein, weshalb rote Blutzellen bei der Bildung eines Gerinnsels adhärieren. Die Interaktion von PS mit seinen Rezeptoren und eine PS-PS-Interaktion in Gegenwart von Ca2+ übernehmen hierbei wahrscheinlich eine wichtige Rolle. Die vorgeschlagene Kaskade von Kaestner und Bernhardt, die eine aktive Beteiligung roter Blutzellen an der Thrombusentstehung beschreibt, wird durch Experimente gestützt. Die Exposition von PS an die Außenseite der Membran ist hierbei ein wichtiger Faktor, welcher der Signalweiterleitung während der Thrombusentstehung dient. Die Frage bezüglich des intrazellulären Ca2+-Gehalts in roten Blutzellen wurde beantwortet. Es gibt keinen signifikanten Unterschied im Gehalt an freiem intrazellulärem Ca2+ zwischen jungen und alten roten Blutzellen.

The chapter describes the likely molecular mechanisms leading to the aggregation of human red blood cells (RBCs) under conditions of physiological coagulation when prostaglandin E2 (PGE2) or lysophosphatidic acid (LPA) is released from activated platelets and under pathophysiological conditions, in particular thrombi formation in sickle cell disease when patients are in a vaso-occlusive crisis. In both scenarios cation channels are activated. This leads to an increase of the free intracellular Ca2+ concentration resulting in an activation of the lipid scramblase, which in turn mediates a movement of phosphatidylserine (PS) from the inner to the outer membrane leaflet. In addition, the increased Ca2+ concentration leads to the activation of the Gardos channel. Experiments suggesting this mechanism have been performed with fluorescence microscopy, flow cytometry as well as single-cell force spectroscopy. The Ca2+-triggered RBC aggregation force has been identified to be close to 100 pN, a value large enough to play a significant role during thrombus formation or in pathological situations.