[Clinical characteristics of pertussis in hospitalized children under 3 months].

Demographic data and clinical data were collected retrospectively from patients with pertussis at the Children's Hospital Affiliated to the Capital Institute of Pediatrics between March 2011 and February 2023. Among the 270 hospitalized patients, 151 cases were male and 119 were female. The youngest age of admission was 10 days and the eldest age of admission was 11 years. The 270 hospitalized patients were divided into two groups according to onset age: <3 months (n=143) and≥3 months (n=127). For those in the <3-month-old group, the incidence of severe pneumonia and severe pertussis were 21.0% and 38.5%, respectively, both were significantly higher than those in≥3-month-old group (7.9% and 11.0%, both P<0.05). For those in the <3-month-old group, paroxysmal spasmodic cough, post-tussive vomiting, paroxysmal cyanosis, apnea, and decreased heart rate after coughing were 86.7%, 25.2%, 38.5%, 7.0% and 16.8%, respectively, all were significantly higher than those in ≥3-month-old group (76.4%, 10.2%, 15.7%, 1.6% and 1.6%, all P<0.05). For those in the<3-month-old group, the incidence of hypoxemia, respiratory failure, were 36.4%, 16.8%, respectively, and both were significantly higher than those in≥3-month-old group (10.2%, 7.1%, P<0.05). It indicated that among the infants under 3 months, the incidence of vomiting after coughing, paroxysmal cyanosis, apnea, hypoxemia, respiratory failure, decreased heart rate after coughing and severe pneumonia were significantly higher than those above 3 months. Infants under 3 months were prone to severe pertussis.

[Clinical characteristics of paroxysmal nocturnal hemoglobinuria (PNH) complicated with ischemic bowel disease].

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired hematopoietic stem cell disease. Gastrointestinal involvement is rarely seen in PNH. This study aims to analyze the clinical features in PNH patients complicated with ischemic bowel disease. Clinical date of 6 patients were collected at Peking Union Medical College Hospital from January 2010 to December 2020. The clinical manifestations, laboratory tests,imaging, endoscopic,and histopathological features and treatment were analyzed.Five in 6 patients were men, with a median age of 31 years old at onset. Most of disease course were recurrent episodes of chronic disease, with abdominal pain (5/6) and gastrointestinal bleeding (5/6). Laboratory examinations showed pancytopenia, reticulocytosis, elevated serum lactate dehydrogenase, high D-dimer and C-reactive protein levels in all patients. Multiple segments of small intestine were the most commonly involved and colon was also affected. Abdominal CT scan showed thickening and roughness or exudation of the intestinal wall (6/6), increased mesenteric density or "comb sign"(4/6), and cholestasis or gallbladder stones (5/6). Endoscopic manifestations included irregular shallow ulcers in the annular cavity (5/6), swelling mucosa with well-defined margins (6/6). Pathological biopsy revealed chronic inflammation of mucosa. The efficacy of steroids combined with anticoagulant therapy was better than that of steroids alone. Ischemic bowel disease in PNH patients is different from typical ischemic enteritis. Young patients, involvement of intestine with multiple segments are common characteristics. The anticoagulant is an essential agent for these patients.

[Value of procalcitonin in predicting the severity and prognosis of neonates with septicemia].

Objective: To explore the value of procalcitonin(PCT) in predicting the severity and prognosis of neonates with septicemia. Methods: The clinical data of the hospitalized neonates over the age of 72 hours with double positive blood cultures from December 1st, 2011 to September 30, 2017 at the neonatal intensive care unit of Children's Hospital Affiliated to Capital Institute of Pediatrics was analyzed retrospectively. Results: A total of 75 neonates were included in the study. There was a significant negative correlation between PCT and neonatal critical illness score (r=-0.440, P<0.05). Among the groups of non-critical, critical and extremely critical, the levels of PCT had significant difference [0.27(0.10-2.55), 4.34(1.24-20.32), 19.49(1.92-106.49)µg/L, H=20.717, P<0.01]. At a cut-off point of 0.56 µg/L, PCT showed 88.6% sensitivity and 61.3% specificity for critical group diagnosis, with optimal area under the curve of 0.804 (P<0.05). At a cut-off point of 11.45 µg/L, PCT showed 65.2% sensitivity and 82.7% specificity for extremely critical group diagnosis, with optimal area under the curve of 0.735 (P<0.05). Among the groups of none organ dysfunction, single organ dysfunction and shock or multiple organ dysfunction, the levels of PCT had significant difference[0.10(0.43-2.56), 3.18(0.67-20.95), 18.97(1.92-82.90) µg/L, H=20.299, P<0.01]. At a cut-off point of 2.64 µg/L, PCT showed 70.0% sensitivity and 77.1% specificity for single organ dysfunction diagnosis, with optimal area under the curve of 0.793 (P<0.05). At a cut-off point of 9.06 µg/L, PCT showed 61.3% sensitivity and 86.4% specificity for shock or multiple organ dysfunction diagnosis, with optimal area under the curve of 0.782 (P<0.05). PCT levels were significantly higher in the death group than the survival group. At a cut-off point of 75.65 µg/L, PCT showed 80.0% sensitivity and 90.0% specificity for the judgment of death, with optimal area under the curve of 0.886 (P<0.05). C-reactive protein (CRP), white blood cell (WBC) and neutrophil lymphocyte ratio (NLR) had no significant difference in the severity and the degree of organ dysfunction of neonates with septicemia(all P>0.05). Conclusion: Compared to CRP, WBC and NLR, PCT has high value in predicting the severity, the degree of organ dysfunction and the prognosis of neonates with septicemia.

[A clinic analysis of thoracolumbar vertebral fracture cascade].

Objective: To observe the clinical characteristics of thoracolumbar vertebral fracture cascade, analyze the relationship between the baseline fractures and the subsequent fractures and compare the distribution differences of subsequent fractures following vertebral augmentation or non-operation. Methods: From July 2012 to August 2016, 1 363 patients admitted to the First Affiliated Hospital of Soochow University with vertebral augmentation for the treatment of vertebral fractures were retrospectively analyzed.There were 190 cases of vertebral fracture cascade, 160 females and 30 males, with an average age of (74±9) years.The location and sequence of all vertebral fractures were recorded.The relationships between the baseline and the subsequent fractures were analyzed.According to different treatment on the baseline vertebral fractures, 190 cases were divided into vertebral augmentation group and non-operation group.The distribution differences of the subsequent fractures following vertebral augmentation and non-operation were compared with chi-square test. Results: Vertebral fracture cascade mainly located in the thoracolumbar spine T(11)-L(2) with an incidence of 52.0%.According to the direction of fracture development, the fracture cascade could be divided into up, down, centrifugation and concentration, and the incidence was 39.8%, 39.2%, 8.4% and 12.6%, respectively.The closer the vertebral body to the baseline fractures, the subsequent fractures incidence was higher.For distance with zero, one, two, three and four vertebrae, the incidence of subsequent vertebral fractures was 36.5%, 26.2%, 15.2%, 11.5% and 3.7%, respectively.A linear relationship was found between the subsequent fractures and the baseline fractures with a correlation coefficient of 0.90.The distribution difference of subsequent fractures between vertebral augmentation and non-operation group was not significant (χ(2)=17.16, P>0.05). Conclusions: The main directions of vertebral fracture cascade is up or down spiral development.The closer the vertebral body to the baseline fractures, the subsequent fractures incidence is higher.Vertebral augmentation doesn't affect the distribution of subsequent fractures.

Stimulation of dendritic cell maturation and induction of apoptosis in lymphoma cells by a stable lectin from buckwheat seeds.

The present study aims to purify and characterize lectin from tartary buckwheat seeds and study its properties as well as biological activities to determine its possible biomedical applications in promoting maturation and proliferation of peripheral blood DCs derived from healthy donors and to study the effect of inducing apoptosis in human leukemia U937 cells. A novel tartary buckwheat lectin (TBL) protein, purified from tartary buckwheat seeds, showed a single band with a molecular mass of 65 kDa in SDS-PAGE. The purified TBL hemagglutinated both human and animal erythrocytes and showed preference for blood type O and the rabbit blood type. TBL is active at up to 60°C, and it is acid- and alkali-stable. TBL (25 µg/mL) combined with 5 x 10(-5) M rhIL-4 promotes maturation and proliferation of peripheral blood dendritic cells (DCs), which is stronger than that promoted by rhTNF-α (20 ng/mL). Exposure of DCs to 50 µg/mL TBL for 48 h resulted in extensive upregulation of maturation markers CD83 and CD40. These TBL-DCs were capable of producing several pro-inflammatory cytokines such as interleukin-10 (IL-10) and interleukin-12 (IL-12). The results of the treatment of human leukemia U937 cells with TBL in doses of 12.5, 25, 50, and 100 µg/mL showed that tartary buckwheat-derived lectin induces apoptosis in a dose-dependent manner. Our results encourage the use of tartary buckwheat and tartary buckwheat-derived lectins as immunopotentiating foods, targeted to strengthen immune responses and display a potential dietary supplement for cancer prevention.

[Preventing and treating anterior commissure adhesion with mucosal flap: a study in canines and clinical cases].

Objective: To evaluate the effectiveness of mucosal flap combined with silicone keel for preventing and treating anterior commissure adhesion in canines and clinical cases. Methods: A prospective experiment was performed from November 2019 to June 2021. Twenty five canines were randomly divided into 5 groups(A, B, C, D, E). Group A, B, C, D received anterior commissure injury by CO2 laser, then separately treated with free mucosal flap-keel complex,intralaryngeal mucosal flap-keel complex, silicone keels and without treatment, group E didn't injure the vocal cord after intubation. The keel was removed after 2 weeks, the larynx was harvested after 4 weeks. The effectiveness of anterior commissure adhesion prevention was evaluated by manifestation under laryngoscope, standard vocal cord length and standard glottic area. A retrospective analysis was performed on sixteen patients with anterior commissure lesion, who underwent mucosal flap-keel technique in Huashan Hospital of Fudan University from January 2019 to January 2021 (10 cases with free mucosal flap-keel complex and 6 cases with intralaryngeal mucosal flap-keel complex). All the patients underwent evaluation of laryngeal function included manifestation under laryngoscope each month and voice analysis before and 3 month after surgery. SPSS 20.0 software was used for statistical analysis. Results: No surgery accident or complication happened in canines and patients. The standard vocal cord length and standard glottic area after 4 weeks in group B were significantly higher than those in group A, C, D (Hstandard vocal cord length=31.688, Hstandard glottic area=16.444, P<0.05). The standard vocal cord length and standard glottic area after 4 weeks in group A were also significantly higher than those in group C, D(Hstandard vocal cord length=20.936, Hstandard glottic area=11.786, P<0.05). The standard vocal cord length and standard glottic area after 4 weeks in group A, B, E were not significantly different to that before surgery(tA left standard vocal cord length=2.636, tA right standard vocal cord length=2.582, tB left standard vocal cord length=2.707, tB right standard vocal cord length=2.673, tE left standard vocal cord length=0.370, tE right standard vocal cord length=0.821, tA standard glottic area=2.731, tB standard glottic area=2.753, tE standard glottic area=-0.529, P>0.05). The standard vocal cord length and standard glottic area after 4 weeks in group C, D were significantly lower than those before surgery(tC left standard vocal cord length=16.137, tC right standard vocal cord length=13.984, tD left standard vocal cord length=11.903, tD right standard vocal cord length=14.587, tC standard glottic area=10.280, tD standard glottic area=22.974, P<0.05). During 6-18 months of follow-up in clinical patients, no one developed a glottic web. Three months after surgery, Jitter, Shimmer, noise to harmonic ratio(NHR), the maximum phonation time(MPT)in all patients were significantly different from preoperative(tintralaryngeal mucosal flap jitter=24.885, tintralaryngeal mucosal flap shimmer=22.643, tintralaryngeal mucosal flap NHR=6.202, tintralaryngeal mucosal flap MPT=-9.661, tfree mucosal flap jitter=25.459, tfree mucosal flap shimmer=18.683, tfree mucosal flap NHR=5.705, tfree mucosal flap MPT=-20.840, P<0.05). Conclusion: Mucosal flap combined with silicone keel is an effective technique for preventing and treating anterior commissure adhesion. The effect of pedicled intralaryngea lmucosal flap is better.

Reproducible measurement of single-molecule conductivity.

A reliable method has been developed for making through-bond electrical contacts to molecules. Current-voltage curves are quantized as integer multiples of one fundamental curve, an observation used to identify single-molecule contacts. The resistance of a single octanedithiol molecule was 900 +/- 50 megohms, based on measurements on more than 1000 single molecules. In contrast, nonbonded contacts to octanethiol monolayers were at least four orders of magnitude more resistive, less reproducible, and had a different voltage dependence, demonstrating that the measurement of intrinsic molecular properties requires chemically bonded contacts.

[Relationship between plasma fibroblast growth factor-23 and subclinical cardiovascular damages in children with primary hypertension].

Objective: To examine the plasma fibroblast growth factor-23 (FGF-23) concentration in children with primary hypertension and to investigate the association between plasma FGF-23 and subclinical cardiovascular damages,and to identify its predictive value for diagnosis. Methods: With prospective study,77 patients (61 males and 16 females) who were diagnosed as primary hypertension with the average age of (11.8±2.2) years were enrolled with informed consent in Children's Hospital,Capital Institute of Pediatrics from October 2016 to December 2017. Carotid wall intima-media thickness (cIMT) measured by Doppler ultrasound and left ventricular hypertrophy (LVH) identified by echocardiography were assessed as parameters of subclinical cardiovascular damages. Patients were divided into increased cIMT group (n=18) and normal cIMT group (n=46) (64 patients with complete data of cIMT). According to left ventricular geometry,patients were divided into LVH group (n=27) and normal geometry group (n=50). Concentration of plasma FGF-23 was detected in all children by enzyme linked immunosorbent assay test. Mann-Whitney U test was used to compare plasma levels of FGF-23 between groups. Kendall's tau-b correlation coefficient was used to analyze the correlation between plasma FGF-23 and cIMT/LVH. Receiver operating characteristic (ROC) curve was used to analyze the value of plasma FGF-23 in the prediction of subclinical cardiovascular damage. Results: The concentration of plasma FGF-23 in the increased cIMT group was higher than that in the normal cIMT group (55.6 (46.2,63.5) vs. 48.6 (39.4, 57.3) ×10(3) RU/L, Z=-2.143, P=0.032) . Also, plasma FGF-23 showed positive correlation with cIMT(r=0.222, P=0.032). According to ROC curve analysis,the cutoff value of plasma FGF-23 for prediction of increased cIMT was 53.9×10(3) RU/L (55.6% sensitivity and 71.7% specificity). The concentration of plasma FGF-23 in the LVH group was significantly higher than that in normal geometry group (55.0 (46.8, 65.7) vs. 48.2 (39.5, 56.0)×10(3) RU/L, Z=-2.375, P=0.018). And,plasma FGF-23 was correlated positively with LVH (r=0.224, P=0.018). The concentration of plasma FGF-23 in patients with concentric remodeling (n=10) was significantly higher than that of the normal geometry group (56.9 (49.6, 66.3) vs. 48.2 (39.5,56.0) ×10(3) RU/L, Z=-2.093, P=0.036). According to ROC curve analysis,the cutoff value of plasma FGF-23 for prediction of LVH was 49.1×10(3) RU/L (70.4% sensitivity and 60.0% specificity). Conclusion: The concentration of plasma FGF-23 in children with primary hypertension was correlated positively with LVH and cIMT and had certain predictive value of diagnosis for subclinical cardiovascular damages.

Cryopreservation of human adipose tissues.

Scientific studies on cryopreservation of adipose tissues have seldom been performed. The purpose of our present study is conducted both in vitro and in vivo to develop a novel cryopreservation method that can be used successfully for long-term preservation of human adipose tissues for possible future clinical application. In this study, samples of adipose aspirates were obtained from 36 adult white female patients after liposuction and collected from the middle layer after centrifugation. In the in vitro study, suitable cryoprotectant agents (CPAs) and their concentrations and possible combinations were selected from our preliminary experiment. A combination of dimethyl sulfoxide (Me(2)SO) and trehalose as CPA with the optimal concentration (0.5M Me(2)SO and 0.2M trehalose) was chosen and then used throughout the study. In addition, maximal recovery of adipose tissues was achieved after cryopreservation using slow cooling without seeding (1-2 degrees C/min to -30 degrees C, followed by plunging to -196 degrees C for storage) and fast warming (in 40 degrees C water bath, averaging 35 degrees C/min). Fresh adipose aspirates (Group 1), cryopreserved adipose aspirates without CPAs (Group 2), or cryopreserved adipose aspirates with CPAs (Group 3) were evaluated by integrated adipocyte counts and histology. In the in vivo study, fresh adipose aspirates (Group 1), cryopreserved adipose aspirates without CPAs (Group 2), or cryopreserved adipose aspirates with CPAs (Group 3) were injected into a nude mouse. The retained adipose aspirates (fat grafts) were harvested in each animal at 4 months and their weight, volume, and histology was assessed. In the in vitro study, significantly higher integrated viable adipocyte count (2.06+/-0.54 x 10(6)mL(-1) vs. 1.07+/-0.41 x 10(6)mL(-1), p<0.0011) of adipose aspirates was found in Group 3 compared with Group 2. Group 3 had only a marginally lower integrated viable adipocyte count compared with Group 1 (2.06+/-0.54 x 10(6)mL(-1) vs. 2.57+/-0.56 x 10(6)mL(-1), p=0.083). Histologically, more tissue shrinkage was evident in Group 2 compared with Group 3. In the in vivo study, various degrees of absorption of injected fat grafts were seen in all 3 groups. However, Group 3 had significantly more retained weight and volume of the injected fat grafts than Group 2 (both p<0.0001) but had significantly less retained weight and volume than Group 3 (weight, p=0.009178; volume, p=0.007836). Histologically, a large amount of tissue fibrosis was seen in Group 2, and reasonably well maintained fatty tissue with only a small amount of tissue fibrosis was seen in Group 3. The results from the present in vitro and in vivo studies, for the first time, demonstrate that our preferred cryopreservation method, the combination of 0.5M Me(2)SO and 0.2M trehalose as CPA in addition to the controlled slow cooling and fast rewarming protocol, appears to provide the maximum recovered results in cryopreservation of human adipose tissues and may become a real option after further refinements for cryopreservation of human adipose aspirates in a clinical setting.

lncRNA HOXA11-AS is involved in fracture healing through regulating mir-124-3p.

OBJECTIVE: Long noncoding RNAs (lncRNAs) have been reported to participate in many diseases. Fracture healing is one of these ordinary diseases. This study aims to identify how lncRNA HOXA11-AS affects the progression of fracture healing. MATERIALS AND METHODS: RT-qPCR was performed to detect the level of HOXA11-AS. Moreover, function assays including cell growth assay and cell apoptosis assay were performed to explore how HOXA11-AS functions in fracture healing. Furthermore, the interaction between HOXA11-AS and mir-124-3p was studied by RT-qPCR, luciferase assay, and RNA immunoprecipitation assay. Rescue experiments were performed to verify the interaction between HOXA11-AS and mir-124-3p in vitro. RESULTS: In the research, function assays revealed that HOXA11-AS overexpression inhibited cell proliferation, while HOXA11-AS knockdown promoted cell proliferation in vitro. Moreover, HOXA11-AS overexpression promoted cell apoptosis, while HOXA11-AS knockdown inhibited cell apoptosis in vitro. Furthermore, mechanism assays demonstrated that HOXA11-AS acts a ceRNA via sponging mir-124-3p. Rescue assay demonstrated that HOXA11-AS suppressed cell proliferation and promoted cell apoptosis via targeting mir-124-3p. CONCLUSIONS: These results indicate that HOXA11-AS could inhibit cell proliferation and promote cell apoptosis of osteoblast via sponging mir-124-3p, which may offer a new vision for interpreting the mechanism of fracture healing.

[Predicting value of thrombospondin-2 for coronary artery dilatation in patients with Kawasaki disease].

OBJECTIVE: To investigate the predictive value of thrombospondin-2 in children with coronary artery dilatation secondary to Kawasaki disease. METHOD: This study was a retrospective controlled study, the patients were divided into Kawasaki disease group and control group.Patients first time hospitalized in Children's Hospital Affiliated to Capital Institute of Pediatrics during the acute phase of Kawasaki disease were enrolled in Kawasaki disease group from May 2013 to August 2014.Sixty-four Kawasaki disease patients were enrolled into the Kawasaki disease group based on inclusion and exclusion criteria, including 39 males and 25 females, with an average age of 2.3 years.According to the results of echocardiography of children with Kawasaki disease, patients were divided into coronary artery dilatation group and non-coronary artery dilatation group, there were 33 cases in the coronary dilatation (CAD) group, 26 males and 7 females, the average age was 2.0 years, and 31 cases in the non-coronary dilatation (NCAD) group, 13 males and 18 females, the average age was 2.6 years.The control group consisted of children with fever but excluding vascular inflammatory diseases and healthy children, 32 cases in fever group, 19 males and 13 females, mean age was 4.5 years; in which healthy group had 32 cases, 18 males and 14 females and the average age was 3.3 years. Enzyme linked immunosorbent assay (ELISA) method was used to measure the levels of thrombospondin-1 (TSP-1) and TSP-2 in the plasma of each group, and the related laboratory parameters, and general information was analyzed.Multiple sets of normal distribution of data were compared by analysis of unifactorial analysis of variance and the two groups were compared by two independent samples t-test.Analysis of covariance was used to remove the effect of age.The χ(2) test was used to analyze categeorical data and receiver operating characteristic (ROC) curve for evaluating the predictive value of TSP-2. RESULT: Compared with the febrile group and healthy group, plasma TSP-2 and TSP-1 of Kawasaki disease group was significantly elevated ((33.6±12.5) vs. (21.4±8.8) and (16.4±2.9) µg/L, (10 949±7 241) vs. (7 174±4 807) and (3 661±2 672) µg/L, F=36.861 and 17.339, P both<0.01). The TSP-2 concentration in the group with coronary artery dilatation was significantly higher than the group without it ((36.7±13.1) vs. (30.4±11.1)µg/L, t=2.062, P=0.043). Regarding the predictive effect of TSP-2 for coronary artery dilatation, sensitivity was 54.5%, specificity was 80.6%, and the cut-off point was 33.9 µg/L.When TSP-2 was combined with albumin<35 g/L to predict coronary artery dilatation, the area under the ROC curve was 0.701, sensitivity was 60.0%, specificity was 82.4%, and the cut-off point was 33.8 µg/L. CONCLUSION: During the acute phase of Kawasaki disease, TSP-2 levels were significantly elevated.It could be used to predict the occurrence of coronary artery dilatation.The predictive value of TSP-2 was significantly improved when combined with albumin.

Bias-induced forces in conducting atomic force microscopy and contact charging of organic monolayers.

Contact electrification, a surface property of bulk dielectric materials, has now been observed at the molecular scale using conducting atomic force microscopy (AFM). Conducting AFM measures the electrical properties of an organic film sandwiched between a conducting probe and a conducting substrate. This paper describes physical changes in the film caused by the application of a bias. Contact of the probe leads to direct mechanical stress and the applied electric field results in both Maxwell stresses and electrostriction. Additional forces arise from charge injection (contact charging). Electrostriction and contact charging act oppositely from the normal long-range Coulomb attraction and dominate when a charged tip touches an insulating film, causing the tip to deflect away from the film at high bias. A bias-induced repulsion observed in spin-coated PMMA films may be accounted for by either mechanism. In self-assembled monolayers, however, tunnel current signals show that the repulsion is dominated by contact charging.

[Research on development of gold immunochromagraphic assay test kit for serum Coxsackievirus IgM antibody.].

BACKGROUND: To develop gold immunochromatographic assay (GICA) test kit for serum Coxsackievirus IgM antibody and optimize the key experiment conditions. METHODS: Colloidal gold particles of 20 nm were prepared and coupled with sheep anti-human IgM, the gold immunochromatography assay test kit was setup for serum Coxsackievirus IgM antibody. RESULTS: The spheroidal colloid gold particles of 20 nm showed bright red in color. The minimal stable concentration (MSC) of gold sheep anti-human IgM was 1 ug/ml, and the suitable stable concentration (SSC) was 1.5 ug/ml. The pH 8.2 was appropriate; 30 sera samples were tested by GICA and ELISA, there was no significant difference between the two methods. CONCLUSION: The quality of gold immunochromatography assay test kit is associated with such factors as the quality and quantity of antigen or antibody, colloid gold particles, buffers, etc.

Development of optimal techniques for cryopreservation of human platelets. I. Platelet activation during cold storage (at 22 and 8 degrees C) and cryopreservation.

Using the current blood bank storage conditions at 22 degrees C, the viability and function of human platelets can be maintained for only 5 days. This does not allow for the necessary and extensive banking of platelets needed to treat patients afflicted with thrombocytopenia, a side effect of many invasive surgeries such as cardiopulmonary bypass or bone marrow transplantation. The development of optimal techniques for long-term cryopreservation and banking of human platelets would provide the ability to greatly extend the viable life of the platelet and would fulfill an increasing and urgent need in many clinical applications. To determine the optimal techniques for platelet preservation, the expression of an activation marker, phosphatidylserine, on the platelet membrane during storage at 22 and 8 degrees C as well as during the different freezing preservation processes was examined using flow cytometry and annexin V binding assay. Human platelets were identified by both CD41 and light scatter in flow cytometry. In cryopreservation experiments, effects of the following factors on platelet activation were evaluated: (a) cryoprotective agents (CPAs) type: dimethyl sulfoxide (Me2SO), ethylene glycol (EG), and propylene glycol (PG), (b) CPA concentration ranging from 0 to 3 M, and (c) ending temperatures of a slow cooling process at -1 degrees C/min. Our results demonstrated that (a) approximately 50% of platelets were activated on days 7 and 16 at 22 and 8 degrees C, respectively; (b) platelets were not significantly activated after 30-min exposure to 1 M Me2SO, EG, and PG at 22 degrees C, respectively, and (c) there was a significant difference in cryoprotective efficacy among these three CPAs in preventing platelets from cryoinjury. After being cooled to -10 degrees C, 74% of the cryopreserved platelets survived (nonactivated) in 1 M Me2SO solution, while in 1 M EG and 1 M PG solutions, 62 and 42% of the platelets survived, respectively. Using the information that Me2SO consistently yields higher percentages of nonactivated platelets and does not seem to be cytotoxic to platelets for 30-min exposure time, this was found to be the optimal cryoprotective agent for platelets. In addition, significant Me2SO toxicity to platelets was not noted until Me2SO concentrations exceeded 2 M. Finally, a concentration of 1 M Me2SO proved to be the most effective at all cryopreservation ending temperatures tested (-10, -30, -60, and -196 degrees C). In conclusion, under the present experimental conditions, a storage temperature of 8 degrees C appeared to be much better than 22 degrees C. Although the potential chemical toxicity of 1 M Me2SO, EG, or PG is negligible, 1 M Me2SO was found to be optimum for cryopreservation of human platelets. PG has the least cryoprotective function for low-temperature platelet survival.