G-quadruplex structural variations in human genome associated with single-nucleotide variations and their impact on gene activity.

G-quadruplexes (G4s) formed by guanine-rich nucleic acids play a role in essential biological processes such as transcription and replication. Besides the >1.5 million putative G-4-forming sequences (PQSs), the human genome features >640 million single-nucleotide variations (SNVs), the most common type of genetic variation among people or populations. An SNV may alter a G4 structure when it falls within a PQS motif. To date, genome-wide PQS-SNV interactions and their impact have not been investigated. Herein, we present a study on the PQS-SNV interactions and the impact they can bring to G4 structures and, subsequently, gene expressions. Based on build 154 of the Single Nucleotide Polymorphism Database (dbSNP), we identified 5 million gains/losses or structural conversions of G4s that can be caused by the SNVs. Of these G4 variations (G4Vs), 3.4 million are within genes, resulting in an average load of >120 G4Vs per gene, preferentially enriched near the transcription start site. Moreover, >80% of the G4Vs overlap with transcription factor-binding sites and >14% with enhancers, giving an average load of 3 and 7.5 for the two regulatory elements, respectively. Our experiments show that such G4Vs can significantly influence the expression of their host genes. These results reveal genome-wide G4Vs and their impact on gene activity, emphasizing an understanding of genetic variation, from a structural perspective, of their physiological function and pathological implications. The G4Vs may also provide a unique category of drug targets for individualized therapeutics, health risk assessment, and drug development.

Addition of oligosaccharide decreases the freezing lesions on human red blood cell membrane in the presence of dextran and glucose.

Although incubation with glucose before freezing can increase the recovery of human red blood cells frozen with polymer, this method can also result in membrane lesions. This study will evaluate whether addition of oligosaccharide (trehalose, sucrose, maltose, or raffinose) can improve the quality of red blood cell membrane after freezing in the presence of glucose and dextran. Following incubation with glucose or the combinations of glucose and oligosaccharides for 3h in a 37°C water bath, red blood cells were frozen in liquid nitrogen for 24h using 40% dextran (W/V) as the extracellular protective solution. The postthaw quality was assessed by percent hemolysis, osmotic fragility, mean corpuscle volume (MCV), distribution of phosphatidylserine, the postthaw 4°C stability, and the integrity of membrane. The results indicated the loading efficiency of glucose or oligosaccharide was dependent on their concentrations. Moreover, addition of trehalose or sucrose could efficiently decrease osmotic fragility of red blood cells caused by incubation with glucose before freezing. The percentage of damaged cell following incubation with glucose was 38.04±21.68% and significantly more than that of the unfrozen cells (0.95±0.28%, P<0.01). However, with the increase of the concentrations of trehalose, the percentages of damaged cells were decreased steadily. When the concentration of trehalose was 400mM, the percentage of damaged cells was 1.97±0.73% and similar to that of the unfrozen cells (P>0.05). Moreover, similar to trehalose, raffinose can also efficiently prevent the osmotic injury caused by incubation with glucose. The microscopy results also indicated addition of trehalose could efficiently decrease the formation of ghosts caused by incubation with glucose. In addition, the gradient hemolysis study showed addition of oligosaccharide could significantly decrease the osmotic fragility of red blood cells caused by incubation with glucose. After freezing and thawing, when both glucose and trehalose, sucrose, or maltose were on the both sides of membrane, with increase of the concentrations of sugar, the percent hemolysis of frozen red blood cells was firstly decreased and then increased. When the total concentration of sugars was 400mM, the percent hemolysis was significantly less than that of cells frozen in the presence of dextran and in the absence of glucose and various oligosaccharides (P<0.01). However, when both glucose and trehalose were only on the outer side of membrane, with increase of the concentrations of sugars, the percent hemolysis was increased steadily. Furthermore, addition of oligosaccharides can efficiently decrease the osmotic fragility and exposure of phosphatidylserine of red blood cells frozen with glucose and dextran. In addition, trehalose or raffinose can also efficiently mitigate the malignant effect of glucose on the postthaw 4°C stability of red blood cells frozen in the presence of dextran. Finally, addition of trehalose can efficiently protect the integrity of red blood cell membrane following freezing with dextran and glucose. In conclusion, addition of oligosaccharide can efficiently reduce lesions of freezing on red blood cell membrane in the presence of glucose and dextran.

Manganese superoxide dismutase gene therapy protects against irradiation- induced intestinal injury.

Radiation-induced intestinal injury is a common complication in radiotherapy for solid organ malignancies in abdomen or pelvis. However, currently there are no approved medical countermeasures for radiation-induced intestinal injury. Therefore, it is urgent to develop new treatments for radiation-induced intestinal injury. In the present study, we demonstrated that bone marrow derived mesenchymal stem cells (MSCs) and overexpression of human manganese superoxide dismutase (MnSOD) could ameliorate radiation-induced intestinal syndrome. NOD/SCID mice received abdominal irradiation at a selected dose of 5 Gy, and then infused intravenously with MnSOD-MSCs. Mice body weight, survival and diarrhea were monitored for 30-days. Colonization and differentiation of MnSOD-MSCs in the irradiated intestine were analyzed by histological and immunohistochemical methods. Consequently, our data demonstrated that intravenous administration of MnSOD-MSCs improved survival, decreased diarrhea occurrence and protected the small intestinal structural integrity of irradiated mice. Moreover, intravenously transplanted MnSOD-MSCs could colonize the irradiated intestine and repair injured sites. These findings suggested that MnSOD-MSCs may be an attractive and potential option for radiation-induced intestinal injury.

[Effects of loaded buffer with epigallocatechin gallate on physiological functions of platelets].

This study was aimed to explore the change of aggregation and activation of platelets loaded with epigallocatechin gallate (EGCG). The platelets were treated by loading buffer with different concentrations of EGCG (0, 2.5, 5, 7.5, 10, 12.5, 15, 20 and 30 mmol/L) and were divided into 2.5, 5, 10 mmol/L groups and control group. The physiological and biochemical functions of platelets were observed, including recovery rate, aggregation and activation of platelets. The platelet counts were determined by Counter Cell-DYN 1200. The aggregation activities were tested through turbidimetry, the platelet apoptosis was detected by flow cytometry. The results showed that the concentrations of EGCG loading in platelets of 2.5, 5 and 10 mmol/L groups were 0.4006 ± 0.12, 1.0527 ± 0.1503, 1.6902 ± 0.1112 mmol/L respectively. Along with the increasing of EGCG concentrations in loading-buffer, the EGCG absorbed by platelets increased too. When the concentration of EGCG in loading-buffer exceeded 15 mmol/L, the EGCG absorbed by platelets did not increase. The recovery rate in 2.5 mmol/L loading buffer group was 82.45 ± 0.360% which was lower than that in control group (90.33 ± 1.115%) (p < 0.05). As compared with control group, the recovery rate in 5 mmol/L loading buffer group (57.51 ± 2.468)% and 10 mmol/L loading buffer group (47.45 ± 2.030)% were even significantly lower (p < 0.01). When ADP was used as the inducer, the maximal aggregation rate (MAR) in control group was (63.6 ± 4.037)%, which was higher than that in other EGCG-loading groups (p < 0.01). And the aggregation activity of platelets negatively correlated with the concentration of EGCG in loading-buffer. When THR was used as the inducer, the MAR in control group was (89.3 ± 6.533)% and higher than that those in other groups (p < 0.05), especially in groups with loading-buffer higher than 10 mmol/L EGCG (70.1 ± 5.400%) (p < 0.01). In the experiment of cellular apoptosis, the early apoptosis easy appeared in platelets loaded with EGCG. It is concluded that the EGCG loading in platelets markedly influences the physiological and biochemical functions of platelets, the apoptosis easy occurs in platelets loaded with EGCG. The EGCG accelerates the course of platelet apoptosis.

[Healing effect of lyophilized platelets on rat chronic wound model].

Platelets carry over 20 growth factors, which all have been shown to improve wound healing, particularly recalcitrant wound healing. The aim of this study was to investigate the healing effect of lyophilized platelets on the chronic wounds through establishing diabetic rat chronic wound model. Healthy male SD rats were intraperitoneally injected with streptozotocin (STZ) solution at the dose of 65 mg/kg. The blood glucose and weights were observed every week. The re-epithelialization rates of normal control group (NDR), diabetic group (DR) and diabetic treatment group (TLP) was analysed. Two full thickness skin wounds were incised in the back of the rats. The re-epithelialization rates were observed at 1, 3, 5, 7 and 12 days. The results showed that after induced by streptozotocin for 72 hours, the blood glucose of the DR group was higher than 16.7 mmol/L. 1 week after induced by STZ, the weight of the DR group was significant lighter than that of the NDR group (p < 0.05). The re-epithelialization rate of DR group were lower than that of NDR. After 12 day treatment, the re-epithelialization rates of NDR and TLP groups were 88.1% and 81.8%, which were significantly higher than that of DR group (62.8%). It is concluded that diabetic rat model established by the intraperitoneal injection of streptozotocin can be used as a better diabetic chronic wound model. And the lyophilized platelets have healing effect on diabetic chronic wounds.

Gene therapy for human nasopharyngeal carcinoma by adenovirus-mediated transfer of human p53, GM-CSF, and B7-1 genes in a mouse xenograft tumor model.

Incidence of nasopharyngeal carcinoma (NPC) remains high in endemic regions. Prevention of tumor recurrences and metastases is a crucial approach to improve therapeutic outcome in NPC patients. In this study, we investigated the effects of the cotransfer of the tumor suppressor gene, p53, in combination with the immunostimulatory genes, GM-CSF and B7-1, on tumor regression and subsequent tumor recurrence. We constructed a recombinant adenovirus carrying human wild-type p53, granulocyte-macrophage colony-stimulating factor (GM-CSF), and B7-1 genes (Ad-p53/GM-CSF/B7-1), which mediated high-level expression of these three genes in NPC CNE-1 cells. Ad-p53/GM-CSF/B7-1 infection inhibited the growth of CNE-1 cells and induced tumor-specific cytotoxic T-lymphocytes (CTLs) in vitro. In CNE-1 xenograft tumor models in huPBL-nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice, an intratumoral injection of Ad-p53/GM-CSF/B7-1 resulted in a reduced tumor burden, compared to normal saline (NS) and Ad-p53 controls. Tumors in the Ad-p53/GM-CSF/B7-1 group displayed diffuse necrosis and infiltration of human T-cells. Further, the tumor occurrence of CNE-1 cell rechallenge largely decreased after the primary tumor was intratumorally injected with Ad-p53/GM-CSF/B7-1 in the HuPBL-NOD/SCID mice model. Only 2 of 8 (25%) animals in the Ad-p53/GM-CSF/B7-1 group had developed measurable tumors, which demonstrated extensive necrosis and much more human T-cell infiltration, compared to 5 of 7 (71%) in the NS and Ad-p53 groups. Therefore, the adenovirus-mediated introduction of p53, GM-CSF, and B7-1 genes could improve local control and prevent the recurrence or metastases of NPC tumors, which suggests a potential therapeutic value in NPC treatment.

Changes of phosphatidylserine distribution in human red blood cells during the process of loading sugars.

The plasma membrane of red blood cells permits sugars to be loaded into the cytoplasm simply by incubation in a suitable buffer solution containing the sugar. This may provide some hope for the freeze-drying of human red blood cells. However, the effect of the loading process on red blood cells has not been fully investigated. The exposure of phosphatidylserine (PS) on the surface of the cell can be recognized by macrophages and result in shortened circulation in vivo. This study evaluates the effects of the concentration, the incubation time, and the temperature of exposure of human red blood cells to extracellular trehalose or glucose. Exposure of PS was demonstrated by annexin V labeling. It was shown that the efficiency of loading of glucose was significantly greater than that of trehalose. The loading efficiency of both sugars increased with increase in extracellular sugar concentration, prolongation of incubation time, and increase of incubation temperature. The percentages of cells with exposed PS and of damaged cells were dependent on the extracellular sugar concentration, the incubation time, and the temperature. With an extracellular glucose concentration of 0.8M, the percentage of cells with exposed PS was more than 80% and significantly higher than that of red blood cells loaded with trehalose (approximate 20%, P<0.01). As the incubation time was prolonged, the percentage of PS exposure and of damaged cells also increased. After incubation for 5h, the percentage of red cells with exposed PS following loading with glucose was more than 80% and significantly higher than that of cells loaded with trehalose (40%, P<0.01). In addition, the incubation temperature had a major effect on PS exposure. The percentage of cells with PS exposure and the proportion of damaged cells increased with increase of incubation temperature. At 37 degrees C, the percentage of cells with exposed PS and of damaged cells after loading with glucose was more than 80% and significantly higher than that of cells loaded with trehalose (P<0.01). However, when the temperature was below 25 degrees C, the percentage of cells with exposed PS and of damaged cells after loading with glucose or trehalose were both less than 10%. In conclusion, the loading efficiency for glucose was higher than that for trehalose, but the lesser effect of trehalose on exposure of PS suggests that it can maintain the asymmetrical distribution of membrane phospholipids and the intracellular trehalose can increase the osmotic tolerance of cells.

Adenoviral-mediated transfer of human wild-type p53, GM-CSF and B7-1 genes results in growth suppression and autologous anti-tumor cytotoxicity of multiple myeloma cells in vitro.

Multiple myeloma (MM) remains incurable despite the use of high-dose chemotherapy and stem cell transplantation. However, immunotherapy is expected to offer long-term disease control, or even possibly a cure. We have previously demonstrated the suppressive effect of a recombinant adenovirus carrying human wild-type p53, granulocyte-macrophage colony-stimulating factor, and B7-1 genes (Ad-p53/GM-CSF/B7-1) on the growth of laryngeal cancer cells. In the present study, we evaluated the effects of an Ad-p53/GM-CSF/B7-1-modified myeloma cell vaccine strategy aimed to induce apoptosis and to augment the immunogenicity of MM cells. Both MM cell lines and purified primary myeloma cells were infected with Ad-p53/GM-CSF/B7-1. High expression levels of these three genes were confirmed separately by Western blot, enzyme-linked immunosorbent assay (ELISA), and flow cytometry. When wild-type p53, GM-CSF and B7-1 genes were introduced, the growth of MM cells was inhibited via enhanced apoptosis and the immunogenicity of tumor cells was augmented. The combinatorial effect of these three genes on inducing cytotoxic T lymphocytes (CTLs) was more evident than that of p53 individually or any combinations of two (p53 plus GM-CSF or p53 plus B7-1). Furthermore, significant proliferation of autologous peripheral blood lymphocytes (PBLs) and specific cytotoxicity against autologous primary MM cells were induced in vitro. These results suggest that myeloma cell vaccination co-transferred with p53, GM-CSF and B7-1 genes may be a promising immunotherapeutic approach against MM.

Genetically modified myeloma cell vaccine inducing antitumor immune response in vivo.

This study was aimed to evaluate the in vivo antitumor effect of genetically modified myeloma cell vaccine on human myeloma xenografts implanted into nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. Human immune system was established in NOD/SCID mice by intraperitoneal injection of human peripheral blood lymphocytes (PBLs). After being inoculated subcutaneously with irradiated myeloma cell line sko-007, adenovirally transferred with GFP or p53, granulocyte-macrophage colony-stimulating factor (GM-CSF) and B7-1 genes, huPBL-NOD/SCID mice were challenged by subcutaneous injection of non-transferred sko-007 cells. The results indicated that Ad-p53/GM-CSF/B7-1-infected sko-007 cell vaccination significantly reduced local tumor growth compared with controls. Histopathological and immunohistochemical analysis showed that tumor tissues increasingly displayed diffuse necrosis, mainly caused by apoptosis, accompanied with significant fibroplasias and blood vessel hyperplasia, and human T cells infiltrated into the tumor tissues. It is concluded that transgenic p53, GM-CSF and B7-1 expression produces an immune response against myeloma cells and may be of therapeutic value for multiple myeloma in human being.

[Tendency and mathematical model of relationship of blood ATP content with temperature and time of preservation].

To investigate the relationship of blood ATP content with temperature and time of preservation and to establish its mathematical model, adenosine triphosphate (ATP) concentration was applied as the index of the quality of erythrocytes; systematical study on variation of blood preserved in a series of different temperatures from 4 degrees C to 32 degrees C was performed, and a series of experimental data were obtained. The results showed that when the ATP concentration y = f (d, t, s) in preserved blood was given as the continuous function of the time (d), the temperature (t) and the initiate ATP concentration (s), the model was fitted with the theory of linearity regression in symbolic statistics, and the general mathematical physical equation of the variation of preserved blood quality was deduced. According to the equation, the whole blood in CPDA-1 solution could be efficiently stored for 35, 35, 29, 22, 18, 18, 13, 8, 7, 6, 6, 5, 4, 4 and 3 days in 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 and 32 degrees C, respectively. In conclusion, the general tendency of the variation of preserved blood quality according to the temperature and the time was systematically disclosed for the first time, which would be propitious to estimate the blood quality in various temperatures and to instruct clinical blood transfusion.

[Analysis on ultrastructure of lyophilized red blood cells].

The objective of the present study was designed to evaluate lyophilized red blood cells of the ultrastructure. Blood was drawn from healthy adult. In group 1, sample was fresh blood; in group 2, sample was added 35% glycerine, stored at -80 degrees C for 24 hours; in group 3, red blood cells stored at 4 degrees C for 5 hours, then were lyophilized for 16 hour. The sample was resuspended for measurements of count and electron microscopy study. The result showed that lyophilized red blood cells possessed relative integrated structure, red blood cell recovery was 53%. The mean diameter, optical density and integral optical density of red blood cell were 4.7 +/- 0.4, 0.14 +/- 0.03 and 1.58 +/- 0.46 in group 1; 4.6 +/- 0.7, 0.14 +/- 0.02 and 2.35 +/- 0.64 in group 2; 4.4 +/- 0.4, 0.17 +/- 0.05 and 2.35 +/- 0.46 in group 3, respectively. There was no significant difference in lyophilized and frozen group, but there was significant difference in lyophilized group and normal group. In conclusion, human red blood cells could be successfully lyophilized and possess relative integrated structure. The mean diameter, optical density and integral optical density of lyophilized red blood cells were similar to that of cryopreservation red cells.

[Dynamic changes of ultrastructure of erythrocytes in prolonged preservation at 4 degrees C].

To study the dynamic changes of ultrastructure of erythrocytes in prolonged preservation of blood with preservative fluid containing superoxide dismutase (SOD), the whole blood samples were preserved at 4 degrees C in SOD-containing solution, the morphologic changes of erythrocyte were dynamically ob served by transmission microscopy after preservation for 42, 75 and 85 days, an d the blood samples preserved in GMA solution served as control. Three variance was applied to analyze the data with SAS software. The results showed that the metamorphotic rates of erythrocyte preserved in SOD-containing solution for 42, 75 and 85 days were lower than those of erythrocytes preserved in GMA solution. Most of metamorphotic rates of erythrocyte preserved in SOD-containing solution for 42, 75 and 85 days were correspond to those of erythrocytes preserved in GMA solution for 42 days, or even lower. It is concluded that SOD-containing preservative fluid might help to maintain the normal morphology of erythrocytes in prolonged preservation at 4 degrees C.

[A simple and convenient method for assaying human RBCs glycolysis rate without oxygen].

AIM: To convenience of the methods for assaying red blood cell glycolysis without oxygen condition in the studies. METHODS: Reagent kit of glucose, perchloric acid, visible light prismatic photometer, battle of nitrogen and rocking bed are used in the studies. The process includes 4 steps prepare Tris- HCI solution and so on, assay of red blood cell glycolysis without oxygen condition and account of glycolysis rate. RESULTS: Human red blood cells stored at 4 degrees C for 75 d, in SOD solution, the glycolysis rate is 86.2% +/- 5.0%, distinctly better than GMA solution (39.2% +/- 8.9%). CONCLUSION: The methods of assaying glycolysis without oxygen condition not use Habea's apparatus. The operation is convenient and simple and its determinations can be performed in ordinary laboratory and is is accurate.

[Labeling and survival studies on rabbit RBC].

AIM: To establish a simple and effective method for RBCs labeling and survival assays, and the qualities of rabbit RBCs preserved in GMA solution at 4 degrees C were verified. METHODS: The bloods were taken through the ear arteries of the rabbits. The RBCs were labeled by fluorescein isothiocyanate (FITC), and were reinjected to the same rabbit through ear veins. The percentage of FITC labeled RBCs was assayed by FACS at a series of times after injection. The SAS software was employed to analyze the data and establish the regression equations. The 24-hour recovery and the half-life span of the labeled RBCs were calculated according to the equations. RESULTS: The 24-hour recovery and the half-life span of the labeled RBCs in the control group were 93.76% +/- 5.40% and 22.50% +/- 4.37 days respectively, which was in agreement with the previous papers. The 24-hour recovery and the half-life span of the labeled RBCs in the GMA group were 89.13% +/- 7.10% and 11.41% +/- 1.63 days respectively, which was coincident with the infusion conditions. CONCLUSION: Compared with other methods of RBCs labeling in vivo, FITC labeling was thought to be easier and cheaper to use, which could facilitate the analysis of the biological character of the labeled cells, and could be used to trace the fate of labeled cells.

[Studies of protective effect of SOD on damage of human RBCs stored at 4 degrees C].

AIM: To investigate the mechanism of protective effect of SOD (superoxide dismutase) on damage of RBCs stored at 4 degrees C, the studies of erythrocyte glucose and energy metabolism were performed. METHODS: whole blood collected from healthy donors and stored at 4 degrees C in ACD, GMA and SOD solutions. Before and post storage, some parameters were assayed. Standard methods were used for the in vitro tests. The 24-hour in vivo recoveries were measured by FTTC (Fluorescein 5-isothiocyanate) from SIGMA Company. RESULTS: All parameters of red blood cell glucolysis rate without oxygen condition, ATP, PK (pyruvic kinase) and 24 h recoveries level were 86.2%, 56.4%, 64.3% and 86.2% of normal respectively stored in SOD solution at 4 degrees C for 75 days, distinctly more than in ACD and GMA groups at 75 days stored. The 24 h recovery at 75d in group SOD was near the recovery at 42d in group GMA. CONCLUSION: Whole blood in SOD solution can be stored satisfactorily for 75 days at 4 degrees C, and furnished theoretical evidence for RBCs survival.

[New tactics of human red blood cells stored at 4 degrees C-protective effect of antioxidant solution on red blood cells damage].

Aliquots of venous blood from healthy donor were collected in plastic blood storage bags with ACD, GMA or antioxidant solution (superoxide dismutase, SOD), respectively, and stored at 4 degrees C. After storage for varying periods, the parameters of the blood were detected in the blood samples. Results showed that the parameters of the blood stored at 4 degrees C for 75 days in SOD group were following: the recovery of RBC-Hb was 87.2%, plasma-Hb (mg/L) was 193.2, P50 (mmHg) was 34.0 (normal value was 33.1); deformability (DImax) was 0.2413 (74.3% of normal value). There was no evident hemolysis, color change, air bubble and clots. It was concluded that human RBC stored at 4 degrees C for 75 days with SOD solution, recovery of levels of RBC-Hb and plasma-Hb were accorded with the requirements of "Basic Demands of Blood Station" in China.